It uses a high-energy laser to intercept aerial targets such as photoelectric guidance equipment, drones, guided bombs and mortars.
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While Albert Einstein did pathbreaking work on special relativity and the photoelectric effect at 26, such early discoveries aren't typical.
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While Albert Einstein did pathbreaking work on special relativity and the photoelectric effect at 26, such early discoveries aren't typical.
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The two products affected by the defect are the Kidde dual-sensor (photoelectric and ionization) smoke alarms, models PI2010 and PI9010.
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The Kidde Smoke Alarm Dual Sensor Detector has both photoelectric and ionization sensors to protect you from smoldering and flaming fires.
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It predicts, with dense mathematics, that devices as simple as a thermostat or a photoelectric diode might have glimmers of consciousness, a subjective self.
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But the company, Suzhou Osaitek Photoelectric Technology, is now speeding up plans to produce the components itself, according to He Zhongya, its chief engineer.
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The First Alert Hardwire Photoelectric and Ionization Smoke Alarm is an excellent detector that relies on hardwiring and can detect the two main types of fires.
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Lithium-ion batteries can charge when the wind turns turbines and the sun drops photons on photoelectric cells, and then discharge when they don't—maintaining even distribution on the electrical grid.
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Albert Einstein was a German-born physicist who developed the special and general theories of relativity and won the Nobel Prize for Physics in 1921 for his explanation of the photoelectric effect.
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Way back in 1905, Albert Einstein described a process he called the photoelectric effect (or photoemission), in which electrons get knocked out of the atoms that held them after being struck by light.
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When Einstein set out on his journey, he was in his 40s, already renowned for his work on the photoelectric effect and on relativity, and developing a second reputation as a progressive public figure.
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"The five components of RECOMP II—compute and memory, photoelectric tape reader, typewriter, tape punch, and console—work together to produce problem solutions previously reserved for only the most expensive system," a brochure for the device stated.
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The photoelectric smoke alarm and electrochemical carbon monoxide detector components work as intended, and the Onelink lets out a piercing alarm paired with a too-pleasant voice declaring the source of the fire, which is basically the user-defined location of the Onelink itself.
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Yantai Raytron Technology Co, a Chinese developer of imaging and sensor technology, has already completed pre-listing tutoring from Citic Securities, while several other technology companies, including Venus Medtech (Hangzhou) Inc and Xinguang Photoelectric Technology Co, are receiving tutoring from underwriters, according to regulatory filings.
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The so-called "cross-eyed electronic umpire" introduced that day used mirrors, lenses and photoelectric cells beneath home plate that would, after detecting a strike through three slots around the plate, emit electric impulses that illuminated what The Brooklyn Eagle called a "saucy red eye" in a nearby cabinet.
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Here are the best smoke detectors you can buy:Best smoke detector overall: First Alert Smoke and Carbon Monoxide AlarmBest hardwired smoke detector: Kidde Smoke Alarm Dual SensorBest dual-sensor smoke detector: First Alert Photoelectric and Ionization Smoke AlarmBest smart smoke detector: Nest Protect Smoke and Carbon Monoxide AlarmBest affordable smoke detector: Kidde Hardwire Smoke AlarmUpdated on 07/23/2019 by Les Shu: Updated prices, links, and formatting.
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The investigation of the photoelectric effect laid the foundation for the development of the photoelectric cell, photo electricity and Albert Einstein's quantum light hypothesis.
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The main scientific activity of Yelpidifor Kirillov was in the field of optics. It contains a study of optical and photoelectric effects in silver halides, internal photoelectric effect, the physical basis of the photographic process. During his time at the Institute of Physics Professor Kirilov has created the scientific school of photography and problems associated to the optical and photoelectric properties of crystals. In 1930 Kirillov discovered the negative photoelectric effect (a decrease of current when exposed to light), studied its spectrum and showed that it is associated with the formation of the latent image, thereby establishing the connection between photoelectric and photochemical processes.
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Dome of the Photoelectric Meridian Circle The Tokyo Photoelectric Meridian Circle is a fully automated photoelectric meridian circle at the Mitaka campus of the National Astronomical Observatory of Japan (formerly of the Tokyo Astronomical Observatory) in Tokyo, Japan. It was manufactured by Carl Zeiss Oberkochen, Germany, and installed in Mitaka in 1982. The telescope is equipped with a double-slit photoelectric micrometer, a photomultiplier with a photon counting device, and a set of filters. Systematic observations with the PMC began in December 1985 for about 33,000 stars selected from several source catalogs.
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Photoelectric diode in forward bias configuration, used for measuring the work function We of the illuminated emitter. The photoelectric work function is the minimum photon energy required to liberate an electron from a substance, in the photoelectric effect. If the photon's energy is greater than the substance's work function, photoelectric emission occurs and the electron is liberated from the surface. Similar to the thermionic case described above, the liberated electrons can be extracted into a collector and produce a detectable current, if an electric field is applied into the surface of the emitter.
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Studies by Texas A&M; and the NFPA cited by the City of Palo Alto, California state, "Photoelectric alarms react slower to rapidly growing fires than ionization alarms, but laboratory and field tests have shown that photoelectric smoke alarms provide adequate warning for all types of fires and have been shown to be far less likely to be deactivated by occupants." Although photoelectric alarms are highly effective at detecting smoldering fires and do provide adequate protection from flaming fires, fire safety experts and the National Fire Protection Agency recommend installing what are called combination alarms, which are alarms that either detect both heat and smoke or use both the ionization and photoelectric processes. Some combination alarms may include a carbon monoxide detection capability. The type and sensitivity of light source and photoelectric sensor and type of smoke chamber differ between manufacturers.
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In 1914, Millikan's experiment supported Einstein's model of the photoelectric effect. Einstein was awarded the 1921 Nobel Prize in Physics for "his discovery of the law of the photoelectric effect", and Robert Millikan was awarded the Nobel Prize in 1923 for "his work on the elementary charge of electricity and on the photoelectric effect". In quantum perturbation theory of atoms and solids acted upon by electromagnetic radiation, the photoelectric effect is still commonly analyzed in terms of waves; the two approaches are equivalent because photon or wave absorption can only happen between quantized energy levels whose energy difference is that of the energy of photon. Albert Einstein's mathematical description of how the photoelectric effect was caused by absorption of quanta of light was in one of his Annus Mirabilis papers, named "On a Heuristic Viewpoint Concerning the Production and Transformation of Light".
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The input was done using a photoelectric paper tape reader; the output was provided by a teletype.
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Illinois physics professor Jakob Kunz suggested that Stebbins try a photoelectric cell. Kunz had been doing experimentation on an improved photoelectric cell which was alkali based. Kunz's cell was the predecessor of the modern day "electric eye." Stebbins left for a sabbatical in Europe in fall of 1912.
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The television equipment WRNY used was designed by Pilot Electric's chief engineer, John Geloso. It was similar to the system designed by Uilses A. Sanabria that was used in a demonstration on WCFL in Chicago in June 1928. Both systems used photoelectric cells made by Lloyd Preston Garner; a researcher at the University of Illinois at Urbana Champaign. Paper on photoelectric cells by Lloyd Preston Garner A September 1928 Radio News article about these photoelectric cells noted "their cost is rather staggering".
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In 1905, Albert Einstein published a paper that explained experimental data from the photoelectric effect as being the result of light energy being carried in discrete quantized packets, energising electrons. This discovery led to the quantum revolution. Einstein was awarded the Nobel Prize in Physics in 1921 for "his discovery of the law of the photoelectric effect". The photoelectric effect is also employed in photocells such as can be found in solar panels and this is frequently used to make electricity commercially.
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In June 2010 the City of Albany, California, enacted photoelectric-only legislation after a unanimous decision by the Albany City Council; several other Californian and Ohioan cities enacted similar legislation shortly afterwards. In November 2011, the Northern Territory enacted Australia's first residential photoelectric legislation mandating the use of photoelectric smoke alarms in all new Northern Territory homes. In the Australian State of Queensland, from 1 January 2017, all smoke alarms in new dwellings (or where a dwelling is substantially renovated) must be photoelectric, not also contain an ionisation sensor, be hardwired to the mains power supply with a secondary power source (i.e. battery) and be interconnected with every other smoke alarm in the dwelling so all activate together.
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Video camera tubes in the early days of television used the photoelectric effect, for example, Philo Farnsworth's "Image dissector" used a screen charged by the photoelectric effect to transform an optical image into a scanned electronic signal.Burns, R. W. (1998) Television: An International History of the Formative Years, IET, p. 358, .
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Because of technological progress, self-contained photoelectric sensors have become increasingly smaller. Remote photoelectric sensors used for remote sensing contain only the optical components of a sensor. The circuitry for power input, amplification, and output switching is located elsewhere, typically in a control panel. This allows the sensor, itself, to be very small.
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The early edition of 1968 by Blanco, sometimes referred as simply the "Photoelectric Catalogue" or UBV was replaced by the Mermilliod edition UBV M in 1987 and extended in 1993. As the atmospheric extinction problem associated with the UBV photometric system became evident, the UBV Photoelectric Photometry Catalogue was phased-out in 2000.
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Head Of Department –Prof.Anuradha Hugar Infrastructure / Facilities: Major instruments available in the department: 1\. Photoelectric Colorimeter 2\. Digital Conductivity meter 3\.
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By the effect of gamma-ray photoelectric or the behavior of tangently rub of tungsten needles, the debris powered is charged.
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High-Z materials, e.g. inorganic crystals, are best suited for the detection of gamma rays. The three basic ways that a gamma ray interacts with matter are: the photoelectric effect, Compton scattering, and pair production. The photon is completely absorbed in photoelectric effect and pair production, while only partial energy is deposited in any given Compton scattering.
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Those photoelectric converters are composed of X-ray absorber and electron collector sheets nested concentrically in an onion-like array. Indeed, since X-rays can go through far greater thickness of material than electrons can, many layers are needed to absorb most of the X-rays. LPP announces an overall efficiency of 81% for the photoelectric conversion scheme.
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Conceptual through-beam system to detect unauthorized access to a secure door. If the beam is interrupted, the detector triggers an alarm. A photoelectric sensor, is an equipment used to discover the distance, absence, or presence of an object by using a light transmitter, often infrared, and a photoelectric receiver. They are largely used in industrial manufacturing.
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During the years 1886–1902, Wilhelm Hallwachs and Philipp Lenard investigated the phenomenon of photoelectric emission in detail. Lenard observed that a current flows through an evacuated glass tube enclosing two electrodes when ultraviolet radiation falls on one of them. As soon as ultraviolet radiation is stopped, the current also stops. This initiated the concept of photoelectric emission.
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The invention of the photomultiplier is predicated upon two prior achievements, the separate discoveries of the photoelectric effect and of secondary emission.
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This is due to the usage in the photoelectric effect of all the electrons excited (sufficiently) by the primary electrons of I_1.
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The telescope had an off-axis equatorial mount and was equipped for direct photography, spectroscopy, and photoelectric photometry. Most of the 80 research papers produced over the 11-years life of the observatory used a multicolor single-channel photometer.Olson, E.C. (1984) "Photoelectric Photometry in the Flat Midwest", International Amateur-Professional Photoelectric Photometry Communication, No. 15, p.5. The photographic glass slides produced by the camera and the spectrograph are now stored in the university archives (series number 15/3/13). In addition to the 40-inch telescope, a smaller dome housed a 4-inch Ross-Fecker camera.
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Different types of electromagnetic radiation The total absorption coefficient of lead (atomic number 82) for gamma rays, plotted versus gamma energy, and the contributions by the three effects. Here, the photoelectric effect dominates at low energy. Above 5 MeV, pair production starts to dominate. Even though photons are electrically neutral, they can ionize atoms directly through the photoelectric effect and the Compton effect.
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The observatory additionally has a Cassegrain reflector dedicated to photoelectric measurements of star brightness, and received a pair of astrographs from the Carnegie Corporation.
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Manual third-party lenses are being produced in L-mount by 7Artisans (Photoelectric series), Meyer-Optik (Gorlitz series), and Kipon HandeVision (IBELUX and IBERIT series').
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The UBV Photoelectric Photometry Catalogue, or UBV M, is the star brightness catalogue that complies to the UBV photometric system developed by astronomer Harold Johnson.
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The reflected light would be picked up by a photoelectric cell whose electrical output would vary with the intensity of the light. This system was often called a "flying spot scanner". The early photoelectric cells were not very sensitive, so three or four would be used with the subject in a darkened booth. Another reason for multiple cells is even pickup of reflected light from the subject.
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More accurate sensors can often have minimum detectable objects of minuscule size. Certain types of smoke detector use a photoelectric sensor to warn of smouldering fires.
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In 1992 they won the Amateur Achievement Award of the Astronomical Society of the Pacific for their work in the field of photoelectric photometry of variable stars.
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Background radiation doses in the immediate vicinity of particles of high atomic number materials, within the human body, have a small enhancement due to the photoelectric effect.
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With Jesse Beams from the University of Virginia, Lawrence continued to research the photoelectric effect. They showed that photoelectrons appeared within 2 x 10−9 seconds of the photons striking the photoelectric surface—close to the limit of measurement at the time. Reducing the emission time by switching the light source on and off rapidly made the spectrum of energy emitted broader, in conformance with Werner Heisenberg's uncertainty principle.
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The Tokyo Photoelectric Meridian Circle (PMC) is a meridian circle that observes and records the positions of stars and planets, which are then reported in the PMC catalogs.
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He has an A.B. in Astronomy from Harvard University (1954), and Ph.D. in Astronomy from the California Institute of Technology (1958) where he wrote his dissertation on photoelectric photometry.
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Whitford was born in Milton, Wisconsin, the son of Alfred and Mary Whitford. He earned his B.A. from Milton College (1926) and his Ph.D. from the University of Wisconsin (1932). While studying physics at the University of Wisconsin–Madison, he worked as an assistant to astronomer Joel Stebbins helping him in his study of photoelectric photometry. Whitford developed a device for measuring small currents from photoelectric cells, which allowed them to measure fainter stars.
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The cell array includes cells in a window formation: One or more cells above, below and on each side of the subject. The television receiver would use the output of the photoelectric cell to drive a neon lamp. When the photoelectric cell was detecting a bright spot, the neon lamp would be bright. The receiver also had a scanning disk with the same hole-pattern as the camera and it spun at the same speed.
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Stebbins' photoelectric photometer mounted on the refractor in 1913. When Robert Baker arrived he continued a photoelectric photometry program focusing on variable stars. He continued to use the 12-inch refractor until 1927 when a new photometer was constructed and attached it to the 30-inch reflector telescope in the Observatory annex.The many transformations of the University of Illinois annex, Svec, Michael, 21 (1) 81-93, 2018 Journal of Astronomical History and Heritage.
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Page proposed an emission theory that successfully explained blackbody radiation and other phenomena in electrodynamic terms, but was eventually abandoned in favor of later theories of quantum mechanics. He reported on the photoelectric effect in 1913.L. Page (Nov. 1913) The Photoelectric Effect, American Journal of Science 36: 501–8, link from HathiTrust The theory of relativity generally concerns inertial frames of reference while students of dynamics must consider accelerations due to force.
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In 1905, Albert Einstein provided an explanation of the photoelectric effect, an experiment that the wave theory of light failed to explain. He did so by postulating the existence of photons, quanta of light energy with particulate qualities. In the photoelectric effect, it was observed that shining a light on certain metals would lead to an electric current in a circuit. Presumably, the light was knocking electrons out of the metal, causing current to flow.
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The physics behind the PES technique is an application of the photoelectric effect. The sample is exposed to a beam of UV or XUV light inducing photoelectric ionization. The energies of the emitted photoelectrons are characteristic of their original electronic states, and depend also on vibrational state and rotational level. For solids, photoelectrons can escape only from a depth on the order of nanometers, so that it is the surface layer which is analyzed.
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This activates a photoreceptor channel, leading to a change in membrane potential and cellular calcium ion concentration. Photoelectric signal transduction ultimately triggers changes in flagellar strokes and thus cell movement.
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These have largely been replaced with CCD cameras that can simultaneously image multiple objects, although photoelectric photometers are still used in special situations, such as where fine time resolution is required.
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He was able to establish a theoretical correlation between the Volta Effect and the Peltier Effect. In 1928 he discovered that Enrico Fermi's theory on free electrons could be used to predict the constants of the photoelectric effect and thermionic effect in Volta's and Peltier's equations. In 1930 Perucca turned his attention to the photoelectric effect. He developed a new type of electric-current/voltage measuring device called the Elettrometro di Perucca which was highly sensitive.
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If the frequency and the intensity of the incident radiation are fixed, the photoelectric current I increases with an increase in the positive voltage, as more and more electrons are directed onto the electrode. When no additional photoelectrons can be collected, the photoelectric current attains a saturation value. This current can only increase with the increase of the intensity of light. An increasing negative voltage prevents all but the highest-energy electrons from reaching the collector.
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The photoelectric effect will cause spacecraft exposed to sunlight to develop a positive charge. This can be a major problem, as other parts of the spacecraft are in shadow which will result in the spacecraft developing a negative charge from nearby plasmas. The imbalance can discharge through delicate electrical components. The static charge created by the photoelectric effect is self-limiting, because a higher charged object doesn't give up its electrons as easily as a lower charged object does.
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Heiland Densitometer TRDZ 1 A densitometer is a device that measures the degree of darkness (the optical density) of a photographic or semitransparent material or of a reflecting surface. The densitometer is basically a light source aimed at a photoelectric cell. It determines the density of a sample placed between the light source and the photoelectric cell from differences in the readings. Modern densitometers have the same components, but also have electronic integrated circuitry for better reading.
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69, p. 141, 1964 Wehlau, A., Wehlau, William, "Photoelectric photometry of Comet Arend-Roland (1956h)", AJ Vol. 64, p. 463, 1959 Wehlau, William, "Photometry of γ Equulei and HD 140728", PASP Vol.
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Intensity-dependent phenomena have now been studied in detail with such lasers. Einstein was awarded the Nobel Prize in Physics in 1921 for his discovery of the law of the photoelectric effect.
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The 10-year-lithium-battery-powered smoke alarm was introduced in 1995. The photoelectric (optical) smoke detector was invented by Donald Steele and Robert Emmark of Electro Signal Lab and patented in 1972.
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Apker followed up his work on the photoelectric effect with an investigation of the photoelectric properties of the alkali halides, particularly potassium iodide. In potassium iodide, an ionic crystal, some iodide ions can be removed and their vacant places will be filled by electrons. Called "F-Centers," these defects absorb visible and ultraviolet light, coloring the crystals at photon energies where they are usually transparent. Additionally, the absorption of visible radiation can free trapped electrons inside the crystal and produce photoconductivity.
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Xiamen Bay is an important economic region for Xiamen as well as the whole of Fujian Province.Y. M. Yeung, Jianfa Shen, 2008, The Pan-Pearl River Delta: an emerging regional economy in a globalizing China, Chinese University Press, , , pp. 125–126 The bay has numerous port, transport infrastructure, shipbuilding and petrochemical industries.ChinaCSR.com, July 25, 2008 - Xiamen Bay Photoelectric Industrial City Launched The local government has set up various development areas such as the Xiamen Bay Photoelectric Industrial City to promote economic development.
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The observatory holds significance in astronomy because of its association with the development of selenium and photoelectric cell. The cell revolutionized the science of astronomical photoelectric photometry by the use of electricity to measure the brightness of stars by providing a more precise and accurate measurement compared to the visual and photographic methods common at that time. This branch of astronomy measures stellar magnitude. The research regarding photometry was conducted on a Warner and Swasey refractor telescope in the second-story equatorial room.
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Gentex was founded in 1974 by Fred Bauer as a manufacturer of fire protection products. The company created the first dual-sensor photoelectric smoke detector, considered to be less prone to false alarms, while still quickly detecting smoldering fires. In the early 1990s, Gentex introduced a smoke detector equipped with a strobe light designed to alert the deaf and hard of hearing individuals. Today, Gentex manufactures a complete line of photoelectric detectors for fire alarm systems, standalone, and interconnect systems.
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This idea only became universally accepted in 1919, with Robert Millikan's detailed experiments on the photoelectric effect, and with the measurement of Compton scattering. Einstein concluded that each wave of frequency f is associated with a collection of photons with energy hf each, where h is Planck's constant. He does not say much more, because he is not sure how the particles are related to the wave. But he does suggest that this idea would explain certain experimental results, notably the photoelectric effect.
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A 2004 NIST report concluded that "Smoke alarms of either the ionization type or the photoelectric type consistently provided time for occupants to escape from most residential fires," and, "Consistent with prior findings, ionization type alarms provided somewhat better response to flaming fires than photoelectric alarms (57 to 62 seconds faster response), and photoelectric alarms provided (often) considerably faster response to smoldering fires than ionization type alarms (47 to 53 minutes faster response)." Regular cleaning can prevent false alarms caused by the build-up of dust and insects, particularly on optical type alarms as they are more susceptible to these factors. A vacuum cleaner can be used to clean domestic smoke detectors to remove detrimental dust. Optical detectors are less susceptible to false alarms in locations such as near a kitchen producing cooking fumes.
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The main building has solar panels on its rooftop, which have a capacity of around 50 kilowatt hour (kWh) and photoelectric capacity of 5 kWh, which secures the continuous operation of the whole system.
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He worked from 1918 to develop a system of recording and reproducing synchronized sound on motion picture film.Tykociner, Joseph T., "Photographic recording and photoelectric reproduction of sound," Trans. SMPE, no. 16, 90-119, 1923.
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B.) and master of science (S.M.) degrees. During the summer breaks he worked at General Electric's laboratories in Lynn, Massachusetts and Schenectady, New York. While there he obtained three patents related to photoelectric tubes.
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The sum of the scattering, photoelectric, and pair-production cross-sections (in barns) is charted as the "atomic attenuation coefficient" (narrow-beam), in barns.Nondestructive Testing Handbook Volume 4 Radiographic Testing, ASNT, 2002, chapter 22.
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Geitel and Elster published works on meteorology, nuclear physics, and the photoelectric effects. Geitel recognized the law of radioactive decay in 1899 and coined the term atomic energy. In 1893 he invented the photocell.
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For gamma rays (uncharged), their energy is converted to an energetic electron via either the photoelectric effect, Compton scattering or pair production. The chemistry of atomic de-excitation in the scintillator produces a multitude of low-energy photons, typically near the blue end of the visible spectrum. The quantity is proportional to the energy deposited by the ionizing particle. These can be directed to the photocathode of a photomultiplier tube which emits at most one electron for each arriving photon due to the photoelectric effect.
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Unfortunately, this principle was too complex to use. The method was abandoned a few years after its discovery. One aspect of the Lippmann concept that was ignored at that time relates to spectroscopic applications. Early in 1933, Herbert E. Ives proposed to use a photoelectric device to probe stationary waves to make spectrometric measurements.Herbert E. Ives, Standing light waves, repetition of an experiment by Wiener, using a photoelectric probe surface, JOSA, 1933, 23, pp. 73–83 In 1995, P. ConnesP. Connes, E. le Coarer, 3-D spectroscopy: The historical and logical viewpoint. IAU Colloquium, vol.
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He wrote a paper on `Photoelectric astrometry',Photoelectric astrometry: a comparison of methods for precise image location a subject I had proposed, where he systematically discussed the performance of methods for precise image location from observations. It remains a classical paper. The second paper to mention is about the rigidity of the celestial coordinate system obtained by the one-dimensional observations in a scanning satellite as TYCHO/Option A/Hipparcos. The question was asked in 1976 as mentioned above, but it took years before we had the answer which was affirmative.
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Hertz helped establish the photoelectric effect (which was later explained by Albert Einstein) when he noticed that a charged object loses its charge more readily when illuminated by ultraviolet radiation (UV). In 1887, he made observations of the photoelectric effect and of the production and reception of electromagnetic (EM) waves, published in the journal Annalen der Physik. His receiver consisted of a coil with a spark gap, whereby a spark would be seen upon detection of EM waves. He placed the apparatus in a darkened box to see the spark better.
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The development of electron spectroscopy can be considered to have begun in 1887 when the German physicist Heinrich Rudolf Hertz discovered the photoelectric effect but was unable to explain it. In 1900, Max Planck (1918 Nobel Prize in Physics) suggested that energy carried by electromagnetic waves could only be released in "packets" of energy. In 1905 Albert Einstein (1921 Nobel Prize of Physics) explained Planck's discovery and the photoelectric effect. He presented the hypothesis that light energy is carried in discrete quantized packets (photons), each with energy hν to explain the experimental dobservations.
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Flame photometer FP8800 for simultaneous determination of up to 4 alkali and alkali earth element concentrations in aqueous samples. Courtesy of A.KRÜSS OptronicA photoelectric flame photometer is a device used in inorganic chemical analysis to determine the concentration of certain metal ions, among them sodium, potassium, lithium, and calcium. Group 1 and Group 2 metals are quite sensitive to Flame Photometry due to their low excitation energies. Analysis of samples by Flame photometer In principle, it is a controlled flame test with the intensity of the flame color quantified by photoelectric circuitry.
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The relation accounts for the quantized nature of light and plays a key role in understanding phenomena such as the photoelectric effect and black-body radiation (where the related Planck postulate can be used to derive Planck's law).
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Luo Xiangang (; born December 1970) is a Chinese engineer specializing in photoelectric technology. He is an academician of the Chinese Academy of Engineering currently serves as director of the Institute of Optics and Electronics, Chinese Academy of Sciences.
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This was fitted with a tail made from Bakelite which broke up on impact. It had a photoelectric cell beneath a cover which detonated the bomb if exposed to light to counteract the work of bomb disposal units.
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COSMOS: The SAO Encyclopedia of Astronomy. Swinburne University of Technology. Retrieved May 19, 2017. In 1946, W. W. Morgan and William P. Bidelman published a paper on interstellar reddening using the MK system of spectral classifications and photoelectric photometry.
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Photovoltaic detectors contain a p-n junction on which photoelectric current appears upon illumination. An infrared detector is hybridized by connecting it to a readout integrated circuit with indium bumps. This hybrid is known as a focal plane array.
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In physics, the Dember effect is when the electron current from a cathode (I_3) subjected to both illumination and a simultaneous electron bombardment is greater than the sum of the photoelectric current (I_1) and the secondary emission current (I_2).
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The Institute of Optics and Electronics of the Chinese Academy of Sciences () is a Chinese science research institute located in the town of Wenxing, Shuangliu District of Chengdu, in southwest China's Sichuan province. It is the largest institute of Chinese Academy of Sciences (CAS) in southwest China, founded in 1970. It is a diversified organization with operations in photoelectric tracking measurement, beam control, adaptive optics, astronomical target photoelectric observation and recognition, advanced optical manufacturing, aerospace photoelectric equipment, micro nano optics, microelectronics optics, and biomedical optics. It has more than 1,200 staff, including 2 academicians of the Chinese Academy of Engineering (CAE), 1 winner of National Science Fund for Outstanding Young Scholars, 1 recruitment program of global experts, 1 chief scientist of National 973 Program, 8 state-level experts in the field of opto-electronics, 13 academic and technological research leaders in Sichuan, and 350 senior S&T; personnel.
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The Harvard Concise Dictionary of Music and Musicians. . In 1968, Duchamp and John Cage appeared together at a concert entitled "Reunion", playing a game of chess and composing Aleatoric music by triggering a series of photoelectric cells underneath the chessboard.
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Bradner graduated from Ohio's Miami University in 1936 and later received his doctorate from California Institute of Technology in Pasadena, California, in 1941, writing his thesis on "Electron-optical studies of the photoelectric effect" under the supervision of William Vermillion Houston.
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The first demonstration of the photoelectric effect was carried out in 1887 by Heinrich Hertz using ultraviolet light. Significant for practical applications, Elster and Geitel two years later demonstrated the same effect using visible light striking alkali metals (potassium and sodium). The addition of caesium, another alkali metal, has permitted the range of sensitive wavelengths to be extended towards longer wavelengths in the red portion of the visible spectrum. Historically, the photoelectric effect is associated with Albert Einstein, who relied upon the phenomenon to establish the fundamental principle of quantum mechanics in 1905, an accomplishment for which Einstein received the 1921 Nobel Prize.
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Gamma decay review Accessed Sept. 29, 2014 An emitted gamma ray from any type of excited state may transfer its energy directly to any electrons, but most probably to one of the K shell electrons of the atom, causing it to be ejected from that atom, in a process generally termed the photoelectric effect (external gamma rays and ultraviolet rays may also cause this effect). The photoelectric effect should not be confused with the internal conversion process, in which a gamma ray photon is not produced as an intermediate particle (rather, a "virtual gamma ray" may be thought to mediate the process).
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The electronic properties of ordered, crystalline solids are determined by the distribution of the electronic states with respect to energy and momentum—the electronic band structure of the solid. Theoretical models of photoemission from solids show that this distribution is, for the most part, preserved in the photoelectric effect. The phenomenological three-step model for ultraviolet and soft X-ray excitation decomposes the effect into these steps: # Inner photoelectric effect in the bulk of the material that is a direct optical transition between an occupied and an unoccupied electronic state. This effect is subject to quantum-mechanical selection rules for dipole transitions.
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The density log measures the bulk density of a formation by bombarding it with a radioactive source and measuring the resulting gamma ray count after the effects of Compton Scattering and Photoelectric absorption. This bulk density can then be used to determine porosity.
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A self-contained photoelectric sensor contains the optics, along with the electronics. It requires only a power source. The sensor performs its own modulation, demodulation, amplification, and output switching. Some self-contained sensors provide such options as built-in control timers or counters.
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Light from the Sun hitting lunar dust causes it to become positively charged from the photoelectric effect. The charged dust then repels itself and lifts off the surface of the Moon by electrostatic levitation.Bell, Trudy E., "Moon fountains", NASA.gov, 2005-03-30.
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A joint venture with Foshan Plastic Group Co Ltd and BYD (H.K) Co Ltd,Foshan Plastic Group starts special cell production.(NEWSDESK: Cooperation)(Foshan Jinhui High-Tech Photoelectric Material Co. Ltd.) China Chemical Reporter, 26 February 2006 it manufactures material ion exchange membranes.
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Avalanche multiplication during Townsend discharge is naturally used in gas phototubes, to amplify the photoelectric charge generated by incident radiation (visible light or not) on the cathode: achievable current is typically 10~20 times greater respect to that generated by vacuum phototubes.
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ANS is a box set by Coil. The album uses a strange and esoteric photoelectric synthesizer known as the ANS synthesizer. It was built around half a century ago and still to this day sits where it was originally conceived; in the Moscow State University.
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After the work of Blodgett the field was relatively inactive for several years until in 1971 Hans Kuhn began performing optical and photoelectric experiments with monolayer assemblies using the methods of Langmuir and Blodgett.Kuhn, H. (1971). Interaction of chromophores in monolayer assembles. Pure and Appl.
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Louis Dominique Joseph Armand Dunoyer de Segonzac (14 November 1880 – 27 August 1963) was a French physicist. He was awarded the Valz Prize by the French Academy of Sciences in 1929 for research on spirit levels and on photoelectric cells as applied to astronomy.
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Andrew John Hollis (3 February 1947 – 21 November 2005) was a British astronomer, chartered engineer and chartered loss adjuster. He was the founding director of the Asteroids and Remote Planets Section of the British Astronomical Association (BAA) and was a pioneer in astronomical photoelectric photometry.
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Kepler Mission space photometer Photometry, from Greek photo- ("light") and -metry ("measure"), is a technique used in astronomy that is concerned with measuring the flux or intensity of light radiated by astronomical objects. This light is measured through a telescope using a photometer, often made using electronic devices such as a CCD photometer or a photoelectric photometer that converts light into an electric current by the photoelectric effect. When calibrated against standard stars (or other light sources) of known intensity and colour, photometers can measure the brightness or apparent magnitude of celestial objects. The methods used to perform photometry depend on the wavelength regime under study.
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So when physicists first discovered devices exhibiting the photoelectric effect, they initially expected that a higher intensity of light would produce a higher voltage from the photoelectric device. Einstein explained the effect by postulating that a beam of light is a stream of particles ("photons") and that, if the beam is of frequency , then each photon has an energy equal to . An electron is likely to be struck only by a single photon, which imparts at most an energy to the electron. Therefore, the intensity of the beam has no effect and only its frequency determines the maximum energy that can be imparted to the electron.
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In 1905, Albert Einstein published the theory of the photoelectric effect that firmly established the quantization of light itself. The chapter is an English translation of Einstein's 1905 paper on the photoelectric effect. In 1913, Niels Bohr showed that atoms could only emit discrete amounts of energy, thus explaining the discrete lines seen in emission and absorption spectra.. The landmark paper laying the Bohr model of the atom and molecular bonding. The understanding of the interaction between light and matter that followed from these developments not only formed the basis of quantum optics but also was crucial for the development of quantum mechanics as a whole.
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182: These investigations set in train a line of research on atmospheric electricity and aerosols that was continued by the Nolan brothers, and had a profound influence on physics research in Ireland in the twentieth century. Patrick J. Nolan is best remembered for the 1940s development of the Photoelectric Nucleus Counter with his UCD colleague L. W. Pollak.O'Connor (2001) This counter was long the standard instrument for the measurement of cloud condensation nuclei.National Library of Australia Catalogue The photoelectric nucleus counter / Patrick J. Nolan Nolan Served on the Governing Board of the School of Cosmic Physics at the Dublin Institute for Advanced Studies from 1947-1981.
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In 1906 Eugene Bloch became professor of physics in the special mathematics class at the Saint-Louis secondary school in Paris, where he taught for eleven years. In addition to his teaching, Eugene Bloch also carried out research in the physics laboratory of the Ecole Normale Supérieure on the photoelectric effect and spectroscopy. In 1908 Bloch completed the studies that he had pursued following his thesis and devoted himself to studying the photoelectric effect (discovered by Hertz in 1887 and then studied by Lenard around 1902). Unlike Lenard, Bloch understood the importance of distinguishing various colors, or wavelengths of light, instead of using white light.
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Photocurrent is the electric current through a photosensitive device, such as a photodiode, as the result of exposure to radiant power. The photocurrent may occur as a result of the photoelectric, photoemissive, or photovoltaic effect. The photocurrent may be enhanced by internal gain caused by interaction among ions and photons under the influence of applied fields, such as occurs in an avalanche photodiode (APD). When a suitable radiation is used, the photoelectric current is directly proportional to intensity of radiation and increases with the increase in accelerating potential till the stage is reached when photo-current becomes maximum and does not increase with further increase in accelerating potential.
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A photocathode is a negatively charged electrode in a light detection device such as a photomultiplier or phototube that is coated with a photosensitive compound. When this is struck by a quantum of light (photon), the absorbed energy causes electron emission due to the photoelectric effect.
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Marbella Lighthouse (Spanish: Faro de Marbella) is a lighthouse in Marbella, southern Spain. It was built in 1864 and is high. It is automatic and electric, its light controlled by photoelectric cells. Its light signal is two flashes every 14.5 seconds and its maximum visibility range is .
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Korn experimented and wrote on long-distance photography, the phototelautograph. He pioneered the use of light sensitive selenium cells which took over from the function of the stylus,"17.10.1906: First Photoelectric Fax Transmission ", Deutsche Welle, Accessed 20.11.09 and used a Nernst lamp as a light source.
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Nine Chinese state key laboratories are now under the Institute of Optics and Electronics, such as State Key Laboratory of Optical Technologies for Micro fabrication, CAS Key labs on Beam Control, Adaptive Optics, and Chengdu Measurement and Testing laboratory for Geometrical Parameter and CAS Photoelectric Precision Mechanics.
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And in the 1950s and 1960s, he pioneered photoelectric photometry with a novel four-colour system, now called Strömgren photometric system. Apart from the Danish observatory of Brorfelde, Strömgren was active in the early organisation of the joint European observatory of ESO at La Silla in Chile.
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The company’s product portfolio includes photoelectric sensors, light grids, inductive, capacitive and magnetic sensors, opto-electronic protective devices, vision sensors, detection, ranging and identification solutions such as bar code scanners and RFID readers, analyzers for gas and liquid analysis as well as gas flow measuring devices.
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The successful patent application of the invented Photoelectric sensors and Autocollimation by Erwin Sick on 20 October meant a breakthrough in technical devices and based an entire equipment program. On 3 December 1988 Erwin Sick died at the age of 79 years after a heart attack.
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One category of presence sensing devices is Photoelectric Sensors. Light Curtains also fall into this category. Light curtains use many infrared light beams to form a perimeter around machinery. When two or more consecutively adjacent beams are interrupted, a kill-switch stops the machine until the boundary is reset.
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The sound track could be immediately replayed from the same recorder unit, which also contained photoelectric sensors, somewhat similar to the various sound-on-film technologies of the era.Popular Science. Record Of Voice Now Made On Moving Paper Tape, Popular Science, Bonnier Corporation, February 1934, pp.40, Vol.
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Shive held several patents including Selenium rectifier and method of making it, Directly heated thermocouple, Photoresistive translating device, Selenium rectifier including tellurium and method of making it, Apparatus for and method of treating selenium rectifiers, Semiconductor photoelectric device, Conditioning of semiconductor translators, Semiconductor amplifier, and Alternating gate current.
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The internal components of a photoelectric control for a typical American streetlight. The photoresistor is facing rightwards and controls whether current flows through the heater which opens the main power contacts. At night, the heater cools, closing the power contacts, energizing the street light. Photoresistors come in many types.
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By 1913, Henry Norris Russell had developed the theory of eclipsing binaries, and Stebbins realized that there were many undiscovered ones. He soon found that Beta Aurigae and Delta Orionis were eclipsing binaries. Further discoveries followed. The development of the photoelectric cell by Jakob Kunz revolutionized astronomical photometry.
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The Wisconsin Experiment Package had eleven different telescopes for ultraviolet observations.Wisconsin Experiment Package For example, there was a photoelectric photometer fed by a 16-inch (40.64 cm) telescope with a six- position filter wheel. WEP observed over 1200 targets in ultraviolet light before the mission ended in early 1973.
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The original iconoscope was very noisy due to the secondary electrons released from the photoelectric mosaic of the charge storage plate when the scanning beam swept it across. An obvious solution was to scan the mosaic with a low-velocity electron beam which produced less energy in the neighborhood of the plate such that no secondary electrons were emitted at all. That is, an image is projected onto the photoelectric mosaic of a charge storage plate, so that positive charges are produced and stored there due to photo-emission and capacitance, respectively. These stored charges are then gently discharged by a low-velocity electron scanning beam, preventing the emission of secondary electrons.
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Following preliminary work by Roger Griffin in 1967 to show the feasibility of photoelectric measurements of radial velocities, Mayor worked with André Baranne at the Marseille Observatory to develop COREVAL, a photoelectric spectrometer capable of highly accurate radial velocity measurements, which allow measurement of star movements, orbital periods of binary stars, and even the rotational speed of stars. This research led to various fields of interest, including the study of statistical characteristics of solar-type binary stars. With fellow researcher Antoine Duquennoy, they examined the radial velocities of several systems believed to be binary stars in 1991. Their results found that a subset of these may in fact be single star systems with substellar secondary objects.
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In 1839, Alexandre Edmond Becquerel discovered the photovoltaic effect while studying the effect of light on electrolytic cells. Though not equivalent to the photoelectric effect, his work on photovoltaics was instrumental in showing a strong relationship between light and electronic properties of materials. In 1873, Willoughby Smith discovered photoconductivity in selenium while testing the metal for its high resistance properties in conjunction with his work involving submarine telegraph cables. Johann Elster (1854–1920) and Hans Geitel (1855–1923), students in Heidelberg, investigated the effects produced by light on electrified bodies and developed the first practical photoelectric cells that could be used to measure the intensity of light.Asimov, A. (1964) Asimov's Biographical Encyclopedia of Science and Technology, Doubleday, .
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In the late 1940s, Wallace H. Coulter, motivated by a need for better red blood cell counting methods following the bombing of Hiroshima and Nagasaki, attempted to improve on photoelectric cell counting techniques. His research was aided by his brother, Joseph R. Coulter, in a basement laboratory in Chicago. Their results using photoelectric methods were disappointing, and in 1948, after reading a paper relating the conductivity of blood to its red blood cell concentration, Wallace devised the Coulter principle—the theory that a cell suspended in a conductive medium generates a drop in current proportional to its size as it passes through an aperture. That October, Wallace built a counter to demonstrate the principle.
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Photon energy is transferred to matter in a two-step process. First, energy is transferred to charged particles in the medium through various photon interactions (e.g. photoelectric effect, Compton scattering, pair production, and photodisintegration). Next, these secondary charged particles transfer their energy to the medium through atomic excitation and ionizations.
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Stebbins brought photoelectric photometry from its infancy in the early 1900s to a mature technique by the 1950s, when it succeeded photography as the primary method of photometry. He used the new technique to investigate eclipsing binaries, the reddening of starlight by interstellar dust, colors of galaxies, and variable stars.
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Two photoelectric lightcurve observations from 1980 rendered a rotation period of 7.50 and 7.51 hours (), while a more recent light-curve analysis in 2004 gave a period of hours (or half the previously determined period) with a very low brightness variation of 0.03 in magnitude (), which typically indicates a nearly spheroidal shape.
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Each was cooled to cryogenic temperatures by a mechanical cryocooler. Germanium provided not only detections by the photoelectric effect, but inherent spectroscopy through the charge deposition of the incoming ray. The crystals are housed in a cryostat, and mounted with low-conductivity straps. A tubular telescope structure formed the bulk of the spacecraft.
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Hallwachs was a known as a builder of scientific instruments. Among the devices he invented are the electrometer quadrant and a double refractometer of great precision. Hallwachs was an assistant of Heinrich Hertz, in 1886, before the photoelectric effect was discovered. Hallwachs and Hertz, in 1887, carried on the investigations of electromagnetic waves.
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Photoelectron photoion coincidence spectroscopy (PEPICO) is a combination of photoionization mass spectrometry and photoelectron spectroscopy. It is largely based on the photoelectric effect. Free molecules from a gas-phase sample are ionized by incident vacuum ultraviolet (VUV) radiation. In the ensuing photoionization, a cation and a photoelectron are formed for each sample molecule.
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During an asteroid survey conducted at McDonald Observatory and CTIO in the 1980s, a rotational lightcurve of Kukkamäki was obtained by astronomer Richard Binzel. The photoelectric observation gave a well-defined rotation period of 4.06 hours with a brightness variation of 0.32 magnitude (), superseding a previous result based on a fragmentary lightcurve.
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Electrical generators were installed in 1959, supplemented in 1967–1994 by two wind turbines. The light and rotation are activated automatically by a photoelectric sensor. Although the lighthouse is automated, the site is still manned. The island is open to the public from April to September, as is the lighthouse, by appointment.
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The photoelectric effect. Incoming photons on the left strike a metal plate (bottom), and eject electrons, depicted as flying off to the right. In a 1905 paper, Einstein postulated that light itself consists of localized particles (quanta). Einstein's light quanta were nearly universally rejected by all physicists, including Max Planck and Niels Bohr.
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Graphene quantum dots are studied as an advanced multifunctional material due to their unique optical, electronic, spin, and photoelectric properties induced by the quantum confinement effect and edge effect. They have possible applications in bioimaging, cancer therapeutics, temperature sensing, drug delivery, LEDs lighter converters, photodetectors, OPV solar cells, and photoluminescent material, biosensors fabrication.
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Stoletov's law (or the first law of photoeffect) for photoelectric effect establishes the direct proportionality between the intensity of electromagnetic radiation acting on a metallic surface and the photocurrent induced by this radiation. The law was discovered by Aleksandr Stoletov in 1888. (Reprinted in ; abstract in Beibl. Ann. d. Phys. 12, 605, 1888).
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For example, some chemical reactions are provoked only by light of frequency higher than a certain threshold; light of frequency lower than the threshold, no matter how intense, does not initiate the reaction. Similarly, electrons can be ejected from a metal plate by shining light of sufficiently high frequency on it (the photoelectric effect); the energy of the ejected electron is related only to the light's frequency, not to its intensity.Frequency- dependence of luminiscence pp. 276ff., photoelectric effect section 1.4 in At the same time, investigations of black-body radiation carried out over four decades (1860–1900) by various researchers culminated in Max Planck's hypothesis English translation that the energy of any system that absorbs or emits electromagnetic radiation of frequency ν is an integer multiple of an energy quantum . As shown by Albert Einstein, some form of energy quantization must be assumed to account for the thermal equilibrium observed between matter and electromagnetic radiation; for this explanation of the photoelectric effect, Einstein received the 1921 Nobel Prize in physics.Presentation speech by Svante Arrhenius for the 1921 Nobel Prize in Physics, December 10, 1922.
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Einstein from 1905 to 1923 was virtually the only physicist who took light-quanta seriously. Throughout most of this period, the physics community treated the light-quanta hypothesis with "skepticism bordering on derision" and maintained this attitude even after Einstein's photoelectric law was validated. The citation for Einstein's 1922 Nobel Prize very deliberately avoided all mention of light-quanta, instead stating that it was being awarded for "his services to theoretical physics and especially for his discovery of the law of the photoelectric effect". This dismissive stance contrasts sharply with the enthusiastic manner in which Einstein's other major contributions were accepted, including his work on Brownian motion, special relativity, general relativity, and his numerous other contributions to the "old" quantum theory.
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The main distinction is that the term photoelectric effect is now usually used when the electron is ejected out of the material (usually into a vacuum) and photovoltaic effect used when the excited charge carrier is still contained within the material. In either case, an electric potential (or voltage) is produced by the separation of charges, and the light has to have a sufficient energy to overcome the potential barrier for excitation. The physical essence of the difference is usually that photoelectric emission separates the charges by ballistic conduction and photovoltaic emission separates them by diffusion, but some "hot carrier" photovoltaic device concepts blur this distinction. The first demonstration of the photovoltaic effect, by Edmond Becquerel in 1839, used an electrochemical cell.
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By employing Planck's quantization assumption, Einstein's theory accounted for the observed experimental trend for the first time. Together with the photoelectric effect, this became one of the most important pieces of evidence for the need of quantization. Einstein used the levels of the quantum mechanical oscillator many years before the advent of modern quantum mechanics.
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In the 19th century, it was observed that the sunlight striking certain materials generates detectable electric current - the photoelectric effect. This discovery has laid the foundation of solar cells. Solar cells have gone on to be used in many applications. They have historically been used in situations where electrical power from the grid was unavailable.
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In 1888 Hallwachs formulated the hypothesis that a conductive plate on which to focus ultraviolet light carries a positive charge because the electrons are gouged out. This happened with more intensity in selenium. The phenomenon was seen in the same year by A. Righi. The phenomenon was called 'Hallwachs-Effekt', now called the photoelectric effect.
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Usually high density materials have heavy ions in the lattice (e.g., lead, cadmium), significantly increasing the contribution of photoelectric effect (~Z4). The increased photo-fraction is important for some applications such as positron emission tomography. High stopping power for electromagnetic component of the ionizing radiation needs greater photo-fraction; this allows for a compact detector.
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For example, while developing special relativity, Albert Einstein was concerned with the Lorentz transformation which left Maxwell's equations invariant, but was apparently uninterested in the Michelson–Morley experiment on Earth's drift through a luminiferous aether. Conversely, Einstein was awarded the Nobel Prize for explaining the photoelectric effect, previously an experimental result lacking a theoretical formulation.
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The photovoltaic effect is the generation of voltage and electric current in a material upon exposure to light. It is a physical and chemical phenomenon. The photovoltaic effect is closely related to the photoelectric effect. In either case, light is absorbed, causing excitation of an electron or other charge carrier to a higher-energy state.
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542-557 It contained two biaxial sensor units, refereed as AMR (Anisotropic Magnetic Resistor), with two redundant PCBs equipped with radiation-hardened proximity electronics and two photoelectric cells. Although conventional, this solution provided moderate detection sensitivity (around 3 mV/V/G), good resolution (3 µG) and an acceptable operational range for measuring the geomagnetic field (0.1 mT - 1 nT).
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120 His office was equipped with recording devices (on tapes and discs), bugs, detectors, transparent mirrors, periscopes for indirect observation and sensitive photoelectric cells. His powerful Mercedes- Benz had a recording device and a two-way radio. After 1936, Moruzov established schools for preparing specialists, such as radio-telegraph operators, photo and film experts, and fingerprinters.Eşan, p.
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He retired in 1944, and died in 1959. He is buried in Brookwood Cemetery. He also researched the photoelectric effect, the gyromagnetic effect, the emission of electrons by chemical reactions, soft X-rays, and the spectrum of hydrogen. Richardson married Lilian Wilson, sister of his Cavendish colleague Harold Wilson, in 1906, and had two sons and a daughter.
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Ultrafast optical pulses can be used to generate x-ray pulses in multiple ways. An optical pulse can excite an electron pulse via the photoelectric effect, and acceleration across a high potential gives the electrons kinetic energy. When the electrons hit a target they generate both characteristic x-rays and bremsstrahlung. A second method is via laser-induced plasma.
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Cooled photoelectric detectors are employed for situations requiring higher sensitivity or faster response. Liquid nitrogen cooled mercury cadmium telluride (MCT) detectors are the most widely used in the mid-IR. With these detectors an interferogram can be measured in as little as 10 milliseconds. Uncooled indium gallium arsenide photodiodes or DTGS are the usual choices in near-IR systems.
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Other scientific equipment was mounted on the outside, including micrometeoroid and cosmic ray detectors, and the Yenisey-2 imaging system. The gas jets for its attitude control system were mounted on the lower end of the spacecraft. Several photoelectric cells helped maintain orientation with respect to the Sun and the Moon. There were no rocket motors for course corrections.
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Electron separation energy or electron binding energy, the energy required to remove one electron from a neutral atom or molecule (or cation) is called ionization energy. The reaction leads to photoionization, photodissociation, the photoelectric effect, photovoltaics, etc. Bond-dissociation energy is the energy required to break one bond of a molecule or ion, usually separating an atom or atoms.
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A first rotational lightcurve of Beltrovata was obtained from photoelectric observations made by U.S. astronomers Edward Bowell and Schelte Bus in the 1970s (), and gave a rotation period of hours with a brightness variation of 0.84 magnitude (). In 2000, the Near-Earth Objects Follow-up Program published an identical period but with a higher amplitude of 1.05 magnitude.().
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The Tri-Ergon records were made by a partial reversal of the photoelectric process used to encode the sound track in the first place.. NB This article is stuffed full of highly detailed technical diagrams and explanations (in Swedish) about the Tri-Ergon process and how it was used to make records from a previously recorded soundtrack.
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From 1922 to 1926, Fleischmann studied at the Friedrich- Alexander-Universität Erlangen-Nürnberg and the Ludwig-Maximilians-Universität München. He received his doctorate in 1929 under Bernhard Gudden, director of the Physics Institute at Erlangen; the subject of his thesis was on the photoelectric effect in solid-state physics.Hentschel and Hentschel, 1996, Appendix F; see the entry of Fleischmann.
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As a result of Dr. Stebbins' work determining stellar magnitude using photoelectric photometry, it became standard technique. Due to this astronomical importance the observatory was listed on the National Register of Historic Places on November 6, 1986 and on December 20, 1989 the U.S. Department of Interior designated the U of I Observatory a National Historic Landmark.
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Carlos Jaschek received his Ph.D. in astronomy in 1952. After a year in the United States, he became professor in astrophysics at La Plata University and the director of the Astrophysical Department in 1957. Jaschek's initial research at La Plata involved observing minor planets. He began programs in stellar spectroscopy and worked to develop equipment particularly in photoelectric photometry.
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It displayed an absence of hydrogen lines, but broad, diffuse lines of neutral (non-ionized) helium. This was interpreted as a hydrogen-deficient white dwarf. In 1962, this star was observed with a photoelectric detector and was found to vary in magnitude over a period of 18 minutes. The light curve of the variation displayed a double sinusoid pattern.
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This formula defines the photoelectric effect. Not every photon which encounters an atom or ion will photoionize it. The probability of photoionization is related to the photoionization cross-section, which depends on the energy of the photon and the target being considered. For photon energies below the ionization threshold, the photoionization cross-section is near zero.
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From 1997 to 2003 he was the chairman of the theory committee of the Istituto Nazionale di Fisica Nucleare (INFN). Becchi began with investigations on the photoelectric effect in nuclear physics (topic of his thesis). In the 1960s he worked on quarks and the associated unitary symmetries. Since 1971 he has done work on renormalization theory.
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Photomultiplier technology was pursued to enable television camera tubes, such as the iconoscope and (later) the orthicon, to be sensitive enough to be practical. So the stage was set to combine the dual phenomena of photoemission (i.e., the photoelectric effect) with secondary emission, both of which had already been studied and adequately understood, to create a practical photomultiplier.
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There he received the Porter Ogden Jacobus Fellowship, and worked with Owen Willans Richardson and jointly published several papers on electrons released by ultraviolet light, electron theory and on the photoelectric effect. Richardson went on to receive the Nobel Prize in some of the areas where Compton contributed. In 1912, Compton received his Ph.D. from Princeton summa cum laude.
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When Superman returns with the jewels, the Ultra-Humanite sends diamond drills at Superman, but Superman breaks past them. Curtis stops Ultra from pulling the lever that will destroy the city. Superman then disintegrates the photoelectric cell connections. Confronted again with her ultimate foe, the Ultra-Humanite dives to her apparent doom in the volcano's crater.
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The cross section for the photoelectric process is proportional to Z5, that for pair production proportional to Z2, whereas Compton scattering goes roughly as Z. A high-Z material therefore favors the former two processes, enabling the detection of the full energy of the gamma ray. If the gamma rays are at higher energies (>5 MeV), pair production dominates.
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N3F has a density of 1.3 g/cm3. N3F adsorbs on to solid surfaces of potassium fluoride, but not onto lithium fluoride or sodium fluoride. This property was being investigated so that N3F could boost the energy of solid propellants. The ultraviolet photoelectric spectrum shows ionisation peaks at 11.01, 13,72, 15.6, 15.9, 16.67, 18.2, and 19.7 eV.
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Diagram of the setup of a photovoltaic collection array. Photovoltaics (PV) use silicon solar cells to convert the energy of sunlight into electricity. Operates under the photoelectric effect which results in the emission of electrons. Concentrated solar power (CSP) Uses lenses or mirrors and tracking devices to focus a large area of sunlight into a small beam.
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Actuators may be pneumatic or hydraulic cylinders, or some kind of electromechanical device. Because the web may be fragile — particularly at its edge — non-contact sensors are used. These sensors may be pneumatic, photoelectric, ultrasonic, or infrared. The system’s controls must put the output signals from the sensors in to a form that can drive the actuator.
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This minor planet was named after American physicist and astronomer Albert Whitford (1905–2002), who was a pioneer in photoelectric photometry. Whitford was also a director at the Washburn and Lick observatories, as well as a former president of the American Astronomical Society. The official naming citation was published by the Minor Planet Center on 20 December 1983 ().
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PG is fed into a control unit having proportional-integral- differential characteristics (PID). The PID-signal is added to a constant set point (C2), amplified and fed to an electro-pneumatic transducer (EPT). EPT produces a pressure in the cuff, which, again, alters finger blood volume.Peňáz J: Photoelectric Measurement of blood pressure, volume and flow in the finger.
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Yamakoshi K, Shimazu H, Togawa T: Indirect measurement of instantaneous arterial blood pressure in the human finger by the vascular unloading technique. IEEE Trans Biomed Eng, 27, 3M, 150-5 (1980).Yamakoshi K, Kamiya A: Noninvasive measurement of arterial blood pressure and elastic properties using photoelectric plethysmography technique. Medical Progress through Technology, 12, 123-43 (1987).
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The experimental Horten Ho 229 flying wing series was proposed for consideration, with a form of unusual upward-firing armament for testing on the V4 night fighter prototype, photoelectric fired vertically mounted rockets or recoilless guns, instead of cannon armament inspired by the Jagdfaust."Hitler's Stealth Fighter Re- created." National Geographic, 25 June 2009. Retrieved: 30 September 2010.
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The distribution of the electrons in solid materials can be visualized by angle-resolved photoemission spectroscopy (ARPES). This technique employs the photoelectric effect to measure the reciprocal space—a mathematical representation of periodic structures that is used to infer the original structure. ARPES can be used to determine the direction, speed and scattering of electrons within the material.
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At the time all automobiles were run by gasoline engines. Cobb's Sunmobile model had 12 selenium photoelectric cells on top of a balsa wood body. These solar cells were connected in series-parallel and converted the sun light directly into electricity, which in turn ran a small low-inertia electric motor. The motor rotated at 2000 r.p.m.
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Transparent solar panels use a tin oxide coating on the inner surface of the glass panes to conduct current out of the cell. The cell contains titanium oxide that is coated with a photoelectric dye. Most conventional solar cells use visible and infrared light to generate electricity. In contrast, the innovative new solar cell also uses ultraviolet radiation.
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Later the radiation pressure played an important role in the work of Albert Einstein in connection with mass–energy equivalence and the photoelectric effect. Einstein lived in Pavia at that time (1895), when Bartoli held the Physics chair at the local University. However, it is unknown whether Einstein was directly influenced by Bartoli. Bartoli died in Pavia in 1896.
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The photoelectric effect is the emission of electrons (called "photoelectrons") from a surface when light is shone on it. It was first observed by Alexandre Edmond Becquerel in 1839, although credit is usually reserved for Heinrich Hertz,See, e.g., who published the first thorough investigation in 1887. Another particularly thorough investigation was published by Philipp Lenard in 1902.
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While at General Electric, he began to research the photoelectric effect, which causes matter to emit electrons when exposed to some types of electromagnetic radiation. In 1916 Robert Andrews Millikan, while verifying the photoelectric equations of Albert Einstein, had proposed the idea that photoelectrons emitted from semiconductors should behave in a different way than those emitted from other types of matter, and a very similar theory was advanced by Edward Condon in 1938. In 1948 Apker, working with E. A. Taft and J. E. Dickey, he completed experiments that confirmed Condon's theory. The main discovery made was that photoelectrons from some semiconductors moved much slower than photoelectrons from metals with the same work function, an unexpected result which was used to increase understanding of the electronic structure of semiconductors.
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After further refinements included in a 1928 patent application, Tihanyi's patent was declared void in Great Britain in 1930,Tihanyi, Koloman, Improvements in television apparatus. European Patent Office, Patent No. GB313456. Convention date UK application: 1928-06-11, declared void and published: 1930-11-11, retrieved: 2013-04-25. and so he applied for patents in the United States. In 1923, while employed by the Westinghouse Electric Corporation in Pittsburgh, Pennsylvania, Russian- born American engineer Vladimir Zworykin presented a project for a totally electronic television system to the company's general manager. In July 1925, Zworykin submitted a patent application titled Television System that included a charge storage plate constructed of a thin layer of isolating material (aluminum oxide) sandwiched between a screen (300 mesh) and a colloidal deposit of photoelectric material (potassium hydride) consisting of isolated globules. The following description can be read between lines 1 and 9 in page 2: "The photoelectric material, such as potassium hydride, is evaporated on the aluminum oxide, or other insulating medium, and treated so as to form a colloidal deposit of potassium hydride consisting of minute globules. Each globule is very active photoelectrically and constitutes, to all intents and purposes, a minute individual photoelectric cell".
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More light shines through, more electrons move around hence more current flows between. This process is called photovoltaic and photoelectric effect. Photovoltaic systems directly convert sunlight into electricity. Solar panels are made out of layers of different materials, as you can see in Figure 2, in order of glass, encapsulate, crystalline cells, encapsulate, back sheet, junction box and lastly frame.
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Müller- Thomamühl designed directional controllers for torpedoes and torpedo search equipment and in 1915 built the first air cushion torpedo speedboat. He founded the torpedo command of the Austrian navy and in 1918 made experiments with aircraft torpedoes. He was also the inventor of the photoelectric switch. This device was ready for use in 1916 and was patented in Austria in 1924.
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Famous visitors to the DPM Library include Rabindranath Tagore, Robert A. Millikan,(Robert A. Millikan was an American experimental physicist honored with the Nobel Prize for Physics in 1923 for his measurement of the elementary electronic charge and for his work on the photoelectric effect) S.R. Ranganathan, Khan Sahib, C. N. Annadurai, V.V. Giri, M. Karunanithi, Poet Subramaniya Bharati and many others....
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LeRoy W. Apker (June 11, 1915 – July 5, 1970) was an American experimental physicist. Along with his colleagues E. A. Taft and Jean Dickey, he studied the photoelectric emission of electrons from semiconductors and discovered the phenomenon of exciton-induced photoemission in potassium iodide. In 1955, he received the Oliver E. Buckley Condensed Matter Prize of the American Physical Society for his work.
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The Lab he created continued in this manner through the academic year 1955-56, twenty years after he had moved to other assignments at Cornell.Memorial Statement. As a researcher, Murdock undertook early studies of photoelectric reactions and soon focused on new developments in X-ray physics and, in particular, by the use of X-rays in deducing the structure of crystals.
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The second equation represents Einstein's research into the photoelectric effect, for which he was awarded the Nobel Prize in Physics in 1921, hν = P + 1/2 mv². The third is related to his work on the general theory of relativity, Rμν \+ 1/2 gμνR = κTμν. Below these is an autograph of a scientist. Medal executed in gold, silver and bronze.
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Xiamen's new materials industry is dominated by special metal materials and advanced polymer materials, including photoelectric information materials, new energy, energy saving and environmental protection materials, and advanced carbon nanomaterials. The industry reached an output value of 88.9 billion yuan ($12.95 billion) in 2018. Industrial parks include Xiamen Tongan Xiang'an Hi- tech Industrial Base and Xiamen Torch Hi-Tech Industrial Zone (Xiang'an).
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Stebbins and Kunz also travelled to Wyoming to study the Solar eclipse of June 8, 1918. Dr. Elmer Dershem joined the Observatory staff in 1917 and rebuilt the photometer in the summer of 1919. By 1922, Charles Wylie completed the first Illinois astronomy doctorate for his photoelectric studies of the Cepheid Η Aquilae, and Sigma Aquilae noting its variations due to tidal distortions.
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Photoionization is the physical process in which an incident photon ejects one or more electrons from an atom, ion or molecule. This is essentially the same process that occurs with the photoelectric effect with metals. In the case of a gas or single atoms, the term photoionization is more common. The ejected electrons, known as photoelectrons, carry information about their pre-ionized states.
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As of 2017, the only existing lightcurve of Thaïs gives a rotation period of 72 hours with a brightness variation of 0.08 magnitude (). The fragmentary light curve was obtained by Austrian astronomers from photoelectric observations in the early 1980s. While not being a slow rotator, it has a significantly longer-than average rotation period, if future observations confirm the tentative results.
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Hokuyo Automatic Co., Ltd. () is a global manufacturer of sensor and automation technology headquartered in Osaka, Japan. Hokuyo is known for its 2D and 3D scanning laser range finders for use in AGV, UAV, and mobile robot applications. The company also develops photoelectric switches, optical data transceivers, automatic counters, and automatic doors, primarily for use in factory and logistics automation.
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Einstein received numerous awards and honors, and in 1922, he was awarded the 1921 Nobel Prize in Physics "for his services to Theoretical Physics, and especially for his discovery of the law of the photoelectric effect". None of the nominations in 1921 met the criteria set by Alfred Nobel, so the 1921 prize was carried forward and awarded to Einstein in 1922.
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The emission of electrons from a metal plate caused by light quanta – photons. The photoelectric effect is the emission of electrons when electromagnetic radiation, such as light, hits a material. Electrons emitted in this manner are called photoelectrons. The phenomenon is studied in condensed matter physics, and solid state and quantum chemistry to draw inferences about the properties of atoms, molecules and solids.
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Not only does this disturb occupants, it can also reduce lamp life. A variation of this technology is the 'differential switching' or 'dead-band' photoelectric control which has multiple illuminances it switches from to reduce occupants being disturbed.a b c Li D, Cheung K, Wong S, Lam T. An analysis of energy- efficient light fittings and lighting controls. Applied Energy [serial online].
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Xeromammography is a photoelectric method of recording an x-ray image on a coated metal plate, using low-energy photon beams, long exposure time, and dry chemical developers. It is a form of xeroradiography. This process was developed in the late 1960s by Jerry Hedstrom, and used to image soft tissue, and later focused on using the process to detect breast cancer.
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Baird Television: Crystal Palace Television Studios . Previous color television demonstrations in the U.K. had been via closed circuit. Mechanically scanned color television was also demonstrated by Bell Laboratories in June 1929 using three complete systems of photoelectric cells, amplifiers, glow-tubes, and color filters, with a series of mirrors to superimpose the red, green, and blue images into one full color image.
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"1945 RCA CRV-59AAE Iconoscope Camera", LabGuy's World The accumulation and storage of photoelectric charges during each scanning cycle greatly increased the electrical output of the iconoscope relative to non-storage type image scanning devices. In the 1931 version, the electron beam scanned the granules; while in the 1925 version, the electron beam scanned the back of the image plate.
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Y Canum Venaticorum light curve, including RGB photoelectric measurements The angular diameter of La Superba has been measured at . It is expected to be pulsating but this has not been seen in the measurements. At , this corresponds to a radius of . If it were placed at the position of the Sun, the star's surface would extend beyond the orbit of Mars.
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The 1961 ASA standard PH2.12-1961 American Standard General-Purpose Photographic Exposure Meters (Photoelectric Type) specifies that "The symbol for relative apertures shall be f/ or f : followed by the effective f-number." They show the hooked italic f not only in the symbol, but also in the term f-number, which today is more commonly set in an ordinary non-italic face.
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Incandescent lamps were primarily used for street lighting until the advent of high-intensity gas-discharge lamps. They were often operated at high-voltage series circuits. Series circuits were popular since their higher voltage produced more light per watt consumed. Furthermore, before the invention of photoelectric controls, a single switch or clock could control all the lights in an entire district.
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He continued working on photoelectric photometry when he arrived at Illinois. In 1931-1932 and again in 1938-39 he was a Research Associate of Harvard University while on sabbatical working with Bart Bok’s Star Count Circuit. Starting in 1939, he changed his research focus to the Milky Way and Galactic Structure. Dr. Baker’s professional activities extended through many fields.
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Flame lift-off in oil fired pressure jet burners is an unwanted condition in which the flame and burner become separated. This condition is most commonly created by excessive combustion air and often results in the loss of flame as the photoelectric cell fails to register the light of the flame, this in turn results in a safety lockout of the control box.
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Such investigations began in the middle of the 1960s, when the Physical Electronics Department started studying discontinuous films and discovered the effect of cold electronic emission from such structures. Now, most of the departments work with nanoscale systems to investigate their optical, magnetic, transport, and photoelectric properties. Research activity is also directed to improving the methods for synthesis of nanoscale objects.
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Because the web may be fragile — particularly at its edge — non-contact sensors are used. These sensors may be pneumatic, photoelectric, ultrasonic, or infrared. The system’s controls must put the output signals from the sensors in to a form that can drive the actuator. Web guiding systems work at high speed, constantly making small adjustments to maintain the position of the material.
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When Wilson came under attack for laying off photoelectric research staff, Putnam publicly reaffirmed his confidence in him. As Putnam searched for a new director, he almost put the Lowell Observatory under the control of Harvard University. Donald Menzel, director of the Harvard Observatory, offered to move Harvard's telescope to the Lowell Observatory in exchange for naming the next director.
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The Townsend discharge was also instrumental as a base theory for electron multiplication phenomena, (both DC and AC), within both silicon and germanium. However, the major advances in early discovery and utilisation of the avalanche gain mechanism were a product of the study of Zener breakdown, related (avalanche) breakdown mechanisms and structural defects in early silicon and germanium transistor and p–n junction devices. These defects were called 'microplasmas' and are critical in the history of APDs and SPADs. Likewise investigation of the light detection properties of p–n junctions is crucial, especially the early 1940s findings of Russel Ohl. Light detection in semiconductors and solids through the internal photoelectric effect is older with Foster Nix pointing to the work of Gudden and Pohl in the 1920s, who use the phrase primary and secondary to distinguish the internal and external photoelectric effects respectively.
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The N-slit laser interferometer, introduced by Duarte,F. J. Duarte, Electro-optical interferometric microdensitometer system, US Patent 5255069 (1993) . uses prismatic beam expansion to illuminate a transmission grating, or N-slit array, and a photoelectric detector array (such as a CCD or CMOS) at the interference plane to register the interferometric signal.F. J. Duarte, in High Power Dye Lasers (Springer-Verlag, Berlin, 1991) Chapter 2.
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In 1919 the entrepreneur Paul Gossen founded the Paul Gossen Co. K.-G., a factory of electrical measuring instruments in Baiersdorf, which moved its headquarters to Erlangen in the following year. The company mainly manufactured measuring instruments such as the world's first photoelectric exposure meter OMBRUX from 1933 onwards. The company building on Nägelsbachstraße, which still exists today, was erected between 1939 and 1943.
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A rotational lightcurve of Akka was obtained from photoelectric observation made by Polish astronomer Wiesław Wiśniewski of the University of Arizona in August 1992. The ambiguous lightcurve gave a rotation period of hours with a brightness variation of 0.46 in magnitude (). Alternatively, the body rotates once every hours (or half the previous period) with an amplitude of 0.52, as determined by Czech astronomer Petr Pravec ().
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Although a plain metallic cathode will exhibit photoelectric properties, the specialized coating greatly increases the effect. A photocathode usually consists of alkali metals with very low work functions. The coating releases electrons much more readily than the underlying metal, allowing it to detect the low-energy photons in infrared radiation. The lens transmits the radiation from the object being viewed to a layer of coated glass.
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This minor planet was named after the Japanese village of Mitaka, where the discovering Tokyo Astronomical Observatory was located. Nowadays the city of Mitaka hosts the headquarters of the National Astronomical Observatory of Japan with the Tokyo Photoelectric Meridian Circle, public relation and data centers, and several telescopes. The official naming citation was mentioned in The Names of the Minor Planets by Paul Herget in 1955 ().
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Xu Qin was born in Lianyungang, Jiangsu province, in 1961. He was admitted to the Beijing Institute of Technology in October 1978 to study photoelectric engineering. After graduating in 1982, he was assigned by the state to Factory 559 (later part of Norinco), a military contractor, to conduct scientific research with military applications. He returned to BIT two years later to study for a master's degree.
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Data and Lt. Geordi La Forge (LeVar Burton) discover the presence of cadmium in the crystal and suspect it has photoelectric properties. They disable the lights in the medical lab and the crystal immediately begs for life. Picard peacefully negotiates to return the crystal life form to the surface of the planet where Starfleet will institute a quarantine, leaving the life form to live in peace.
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Created by Christopher Janney, it features a mixture of light and sound throughout the pedestrian tunnel. Within each column are photoelectric sensors and an audio speaker. Also, a riddle is etched on plaques on both ends of the tunnel. If a person can decipher the riddle and trigger the columns in the pattern described, the tunnel will “dance” a pattern of light and sound in reply.
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For example, he recast the theory in terms of classical action.Einstein and the Quantum, A.Douglas Stone, Princeton University Press, Princeton and Oxford, chapter 9, Tripping the light heuristic, 2013. Einstein's hypothesis of light quanta (photons), based on Heinrich Hertz's 1887 discovery (and further investigation by Philipp Lenard) of the photoelectric effect, was initially rejected by Planck. He was unwilling to discard completely Maxwell's theory of electrodynamics.
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The old observatory was made into a library and then torn down to make room for Laird Hall in 1905. The observatory acquired a sidereal clock in 1910. In 1922 Carleton professor Edward Fath constructed one of the nation's first photoelectric photometers in Goodsell. The time service was continued until 1931 and the study of astronomy was prominent at Carleton well into the 20th century.
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PS10 concentrates sunlight from a field of heliostats on a central tower. Solar power is the conversion of sunlight into electricity, either directly using photovoltaics (PV), or indirectly using concentrated solar power (CSP). Concentrated solar power systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam. Photovoltaics convert light into electric current using the photoelectric effect.
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This energy turns out to be comparable to that of bulk tungsten trioxide and molybdenum trioxide. The photoelectric signal is also broad which suggests a large difference in conformation between the anion and the neutral species. Computational chemistry shows that the anions and dianions are ideal hexagons with identical metal-to-metal bond lengths. The molecules discussed thus far only exist diluted in the gas phase.
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Together with his friend Hans Geitel, he has well over 100 publications on atmospheric electricity, the intensity of the starlight, ihe problems of ionizing radiation (example: "On the radioactivity of the earth substrate and its possible relationship to the geothermal") and other important areas of research a valuable contribution paid to the development of physics. Together with Geitel Julius Elster invented a modern photoelectric cell.
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He developed a method to carry out calculations of its transition probabilities. He calculated the photoelectric effect for hydrogen and X-rays, obtaining the absorption coefficient at the K-edge. His calculations accorded with observations of the X-ray absorption of the sun, but not helium. Years later it was realized that the sun was largely composed of hydrogen and that his calculations were indeed correct.
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Historically, classical mechanics had been around for nearly a quarter century before quantum mechanics developed. Classical mechanics originated with Isaac Newton's laws of motion in Philosophiæ Naturalis Principia Mathematica, developed over the seventeenth century. Quantum mechanics developed later, over the nineteenth century, precipitated by Planck's postulate and Albert Einstein's explanation of the photoelectric effect. Both fields are commonly held to constitute the most certain knowledge that exists about physical nature.
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Using multiple bandpass filters with relative photometry is termed absolute photometry. A plot of magnitude against time produces a light curve, yielding considerable information about the physical process causing the brightness changes. Precision photoelectric photometers can measure starlight around 0.001 magnitude. The technique of surface photometry can also be used with extended objects like planets, comets, nebulae or galaxies that measures the apparent magnitude in terms of magnitudes per square arcsecond.
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His cousin, Kirill Fedorovich Nesturkh, then a young physicist, invited him to attend the defense of the dissertation of Abram Fedorovich Ioffe. Physics lecturer Vladimir Konstantinovich Lebedinskiy had explained to Theremin the dispute over Ioffe's work on the electron. On 9 May 1913 Theremin and his cousin attended Ioffe's dissertation defense. Ioffe's subject was on the elementary photoelectric effect, the magnetic field of cathode rays and related investigations.
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Sunny Optical Technology (Group) Company Limited, known as Sunny Optical or just Sunny is a Chinese civilian-run enterprise and listed company that produces optical lenses. Headquartered in Yuyao, Ningbo, Zhejiang Province, Sunny Optical Technology designs, manufactures, and sells optical devices, including lens modules, camera modules, photoelectric vision products, microscopic, analytical and surveying instruments. It is a supplier to major Chinese smartphone brands including Huawei, Oppo and Vivo.
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The trigger reacts to a change in the signal within the light sensor. An optical sensor can measure the changes from one or several light beams. When a change occurs, the light sensor operates as a photoelectric trigger and therefore either increases or decreases the electrical output. An optical switch enables signals in optical fibres or integrated optical circuits to be switched selectively from one circuit to another.
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Thallium is used in its elemental form more often than the other boron-group elements. Uncompounded thallium is used in low-melting glasses, photoelectric cells, switches, mercury alloys for low-range glass thermometers, and thallium salts. It can be found in lamps and electronics, and is also used in myocardial imaging. The possibility of using thallium in semiconductors has been researched, and it is a known catalyst in organic synthesis.
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A photodiode is a PIN structure or p–n junction. When a photon of sufficient energy strikes the diode, it creates an electron–hole pair. This mechanism is also known as the inner photoelectric effect. If the absorption occurs in the junction's depletion region, or one diffusion length away from it, these carriers are swept from the junction by the built-in electric field of the depletion region.
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Incident photons strike the photocathode material, which is usually a thin vapor- deposited conducting layer on the inside of the entry window of the device. Electrons are ejected from the surface as a consequence of the photoelectric effect. These electrons are directed by the focusing electrode toward the electron multiplier, where electrons are multiplied by the process of secondary emission. The electron multiplier consists of a number of electrodes called dynodes.
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The Dominion Observatory building, where Burland spent her career as an astronomer. Burland joined the Astrophysics Division at the Dominion Observatory in 1927, and was the first woman on staff at the Observatory. In the 1930s she served in leadership positions at the Ottawa Centre of the Royal Astronomical Society of Canada (RASC), including a term as president. She worked on photoelectric photometry of Cepheid variables, and later studied meteors.
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The light operates photo eyes become operational when the receiver "receives" the transmitter signal. Dark operate photo eyes become operational when the receiver "does not receive" the transmitter signal. The detecting range of a photoelectric sensor is its "field of view", or the maximum distance from which the sensor can retrieve information, minus the minimum distance. A minimum detectable object is the smallest object the sensor can detect.
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His work is also known for its influence on the philosophy of science. He is best known to the general public for his mass–energy equivalence formula , which has been dubbed "the world's most famous equation". He received the 1921 Nobel Prize in Physics "for his services to theoretical physics, and especially for his discovery of the law of the photoelectric effect", a pivotal step in the development of quantum theory.
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The 2501 uses a photoelectric sensor to read the data punched in the card. Cards are read serially (column by column) and the reader uses a simplified "straight through" card path. "Each column is read twice and the two readings are compared to check reading accuracy." In a mainframe environment the 2501 was frequently used for mainframe input in an "open shop" environment where users submitted their own jobs.
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A solar lamp is operated by batteries charged by solar panels during the day. Electric garden lanterns are usually controlled from inside a building by a wall switch, or by a photoelectric sensor attached to the lamp or nearby. Yard lamps intended to provide security lighting may be controlled by a motion sensor. Gas lanterns that burn continually may be prohibited by some jurisdiction's greenhouse gas environmental regulations.
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The wave view did not immediately displace the ray and particle view, but began to dominate scientific thinking about light in the mid 19th century since it could explain polarization phenomena that the alternatives could not. It was not until the early 20th century that the photoelectric effect introduced firm evidence of a particle nature of light as well, therefore, paving the way for the wave-particle duality of light.
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Mk 53 Proximity fuze for an artillery shell, c. 1945 Proximity fuzes cause a missile warhead or other munition (e.g. air-dropped bomb or sea mine) to detonate when it comes within a certain pre-set distance of the target, or vice versa. Proximity fuzes utilize sensors incorporating one or more combinations of the following: radar, active sonar, passive acoustic, infrared, magnetic, photoelectric, seismic or even television cameras.
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These are known as quantum harmonic oscillators. This process of restricting energies to discrete values is called quantization. Building on this idea, Albert Einstein proposed in 1905 an explanation for the photoelectric effect, that light is composed of individual packets of energy called photons (the quanta of light). This implied that the electromagnetic radiation, while being waves in the classical electromagnetic field, also exists in the form of particles.
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Ivan Stranski (1897–1979) developed the molecular-kinetic theory of crystal formation and crystal growth. The results of his work on crystal structure and behaviour have had wide application in the areas of physical chemistry, metallurgy and mining. Georgi Nadjakov was among Bulgaria's top physicists, and became known for his experiments on the photoelectric effect and most notably, the discovery of photoelectrets. Nadjakov's discoveries are now widely employed in photocopier machines.
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During the first half of the 20th century the ROE pursued the new fields of photographic and photoelectric recording of stellar positions, brightnesses and spectra. From the 1950s onwards the ROE has concentrated even more on instrumentation and automation. In 1965 the ROE moved from the responsibility of the Scottish Office into the new Science Research Council (SRC), which in 1981 became the Science and Engineering Research Council (SERC).
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De Forest Audion tube from 1908, the first triode. The flat plate is visible at top, with the zigzag wire grid under it. The filament was originally under the grid but has burned out. Lieben-Reisz tube, another primitive triode developed the same time as the Audion by Robert von Lieben Before thermionic valves were invented, Philipp Lenard used the principle of grid control while conducting photoelectric experiments in 1902.
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He theorized correctly that the explanation of the light emission was in the new science of quantum mechanics, speculating that it was the inverse of the photoelectric effect discovered by Albert Einstein in 1905. He wrote to Einstein about it, but did not receive a reply. Losev designed practical carborundum electroluminescent lights, but found no one interested in commercially producing these weak light sources. Losev died in World War 2.
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Under his directorship, the study of photoelectric photometry was introduced and the study of comets, variable stars, lunar occultation, solar activity and study of motion of clusters was undertaken. It also participated in the solar and seismological observations as part of the International Geophysical Year (1957-58). A K Das was Director of the Observatory in 1960 for a very short time after his retirement as Director of Kodaikanal Observatory.
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Richard D. Lines (April 21, 1916 - June 29, 1992) was an American amateur astronomer. He started as a deep-sky observer and photographer, but later specialized in photometry of variable stars. He was a member of the American Association of Variable Star Observers and International Amateur-Professional Photoelectric Photometry (I.A.P.P.P.). Together with his wife Helen Chambliss Lines, also a keen astronomer, he built a small observatory in Mayer, Arizona.
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Optical smoke detector with the cover removed Optical smoke detector 1: Optical chamber 2: Cover 3: Case moulding 4: Photodiode (transducer) 5: Infrared LED A photoelectric, or optical smoke detector contains a source of infrared, visible, or ultraviolet light — typically an incandescent light bulb or light-emitting diode (LED) — a lens, and a photoelectric receiver — typically a photodiode. In spot-type detectors, all of these components are arranged inside a chamber where air, which may contain smoke from a nearby fire, flows. In large open areas such as atria and auditoriums, optical beam or projected-beam smoke detectors are used instead of a chamber within the unit: a wall-mounted unit emits a beam of infrared or ultraviolet light which is either received and processed by a separate device or reflected to the receiver by a reflector. In some types, particularly optical beam types, the light emitted by the light source passes through the air being tested and reaches the photosensor.
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Development of cast solid fuel rockets began at the Woolwich Arsenal in the years immediately before the opening of World War II. This research was moved to the newly-formed Ministry of Supply Projectile Development Establishment at Fort Halstead. Three designs were initially developed under the name Unrotated Projectile, a diameter short-range weapon, a short-range weapon that carried a large warhead or a wire intended to snag aircraft, and the anti-bomber weapon that triggered by a photoelectric cell intended to fire when it lost illumination by a searchlight as it passed the target. As the development of the UP series continued, in 1941 the idea was raised that the same photoelectric system could be used to guide the rocket, not just trigger it. This idea had been raised on several occasions in the past, and led to similar development efforts in other UK military research establishments, notably the contemporary Royal Aircraft Establishment (RAE) Ben.
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The "photoelectrons" emitted as a result of the photoelectric effect have a certain kinetic energy, which can be measured. This kinetic energy (for each photoelectron) is independent of the intensity of the light, but depends linearly on the frequency; and if the frequency is too low (corresponding to a photon energy that is less than the work function of the material), no photoelectrons are emitted at all, unless a plurality of photons, whose energetic sum is greater than the energy of the photoelectrons, acts virtually simultaneously (multiphoton effect). Assuming the frequency is high enough to cause the photoelectric effect, a rise in intensity of the light source causes more photoelectrons to be emitted with the same kinetic energy, rather than the same number of photoelectrons to be emitted with higher kinetic energy. Einstein's explanation for these observations was that light itself is quantized; that the energy of light is not transferred continuously as in a classical wave, but only in small "packets" or quanta.
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By making changes to Wien's radiation law (not to be confused with Wien's displacement law) consistent with thermodynamics and electromagnetism, he found a mathematical expression fitting the experimental data satisfactorily. Planck had to assume that the energy of the oscillators in the cavity was quantized, i.e., it existed in integer multiples of some quantity. Einstein built on this idea and proposed the quantization of electromagnetic radiation itself in 1905 to explain the photoelectric effect.
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The Potter Instrument Company of Great Neck, New York developed a photoelectric tag reader for the 1952 pilot system. The reader scanned 100 tags per minute. A lens system enlarged the image of a tag's holes projected by a gas-type photoflash tube onto an array of phototubes. The phototubes fired thyratrons that activated relay logic to translate the tag's coded digits into Hollerith code and punch a standard sized punched card.
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A photoelectric sensor protruded from the center of the ring. The sensor was designed with two photocells which would be triggered by the light of the Moon when the probe was within about 30,000 km of the Moon. At the center of the cone was a voltage supply tube and two Geiger–Müller tubes. The Laboratory's Microlock system, used for communicating with earlier Explorer satellites, did not have sufficient range to perform this mission.
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Polish inventor Jan Szczepanik patented a color television system in 1897, using a selenium photoelectric cell at the transmitter and an electromagnet controlling an oscillating mirror and a moving prism at the receiver. But his system contained no means of analyzing the spectrum of colors at the transmitting end, and could not have worked as he described it.R. W. Burns, Television: An International History of the Formative Years, IET, 1998, p. 98. .
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Caesium vapour thermionic generators are low-power devices that convert heat energy to electrical energy. In the two-electrode vacuum tube converter, caesium neutralizes the space charge near the cathode and enhances the current flow. Caesium is also important for its photoemissive properties, converting light to electron flow. It is used in photoelectric cells because caesium-based cathodes, such as the intermetallic compound , have a low threshold voltage for emission of electrons.
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For example, in some fluorescent tubes a momentary high voltage is applied to the electrodes to start the current through the tube; after starting the electrodes are heated enough by the current to keep emitting electrons to sustain the discharge. Cold cathodes may also emit electrons by photoelectric emission. These are often called photocathodes and are used in phototubes used in scientific instruments and image intensifier tubes used in night vision goggles.
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Pump technology hit a plateau until Geissler and Sprengle in the mid 19th century, who finally gave access to the high-vacuum regime. This led to the study of electrical discharges in vacuum, discovery of cathode rays, discovery of X-rays and the discovery of the electron. The photoelectric effect was observed in high vacuum, which was a key discovery that lead to the formulation of quantum mechanics and much of modern physics.
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Shortly after the turn of the millennium several 614's were converted to TAV (technikbasierte Abfertigungsverfahren) automatic door operation. Door control computers were installed, door handles removed and replaced by door opening buttons and photoelectric beams. Because the new door control system was not very reliable and the vehicles were approaching the end of their service life the TAV installation programme was halted after a few years, even before the end of the remotoring programme.
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Because of the preponderance of evidence in favor of the wave theory, Einstein's ideas were met initially with great skepticism. Eventually, however, the photon model became favored. One of the most significant pieces of evidence in its favor was its ability to explain several puzzling properties of the photoelectric effect, described in the following section. Nonetheless, the wave analogy remained indispensable for helping to understand other characteristics of light: diffraction, refraction, and interference.
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A fourth-order Fresnel lens was first exhibited from the new tower on June 30, 1919. The Coast Guard automated the Lime Kiln Lighthouse in August 1962, using photoelectric cells to turn the light on at dusk and off during daylight hours. In 1998, the drum lens was replaced with a modern optic, flashing a white light once every 10 seconds. Sitting on the rocky shoreline at a height of , the beacon is visible for .
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He called these new particles corpuscles but they were later renamed electrons. Thomson also showed that electrons were identical to particles given off by photoelectric and radioactive materials. It was quickly recognized that electrons are the particles that carry electric currents in metal wires. Thomson concluded that these electrons emerged from the very atoms of the cathode in his instruments, which meant that atoms are not indivisible as the name atomos suggests.
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Turbidimetry (the name being derived from turbidity) is the process of measuring the loss of intensity of transmitted light due to the scattering effect of particles suspended in it. Light is passed through a filter creating a light of known wavelength which is then passed through a cuvette containing a solution. A photoelectric cell collects the light which passes through the cuvette. A measurement is then given for the amount of absorbed light.
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It is also equipped with a spectral prism with a prime angle of 6.10 degrees for stellar spectra, a wedge sensitometer and a film recorder. # The Bamberg refractor #: This telescope is used to determine stellar magnitude, stellar distance, and photometric studies of eclipsing stars, solar imaging, and others. It is equipped with a photoelectric photometer, has a lens diameter with meter of focal length. # The Cassegrain GOTO #: This was a gift from the Japanese government.
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The transmitter projects an array of parallel infrared light beams to the receiver which consists of a number of photoelectric cells. When an object breaks one or more of the beams a stop signal is sent to the guarded equipment. The light beams emitted from the transmitter are sequenced, one after the other, and pulsed at a specific frequency. The receiver is designed to only accept the specific pulse and frequency from its dedicated transmitter.
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In 1955, he moved to Arizona to become the director of the Flagstaff Station of the USNO where he worked on several research programs. In 1966, he was appointed director of the stellar division of Kitt Peak National Observatory (KPNO), where he helped develop the 4-meter Nicholas U. Mayall Telescope. In 1977, he became director of the Lowell Observatory in Flagstaff, Arizona. He was noted for his work in photoelectric and photographic photometry.
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Keyence is a fabless manufacturing company that sells a broad range of products, from the photoelectric sensor and proximity sensors to measuring instruments for inspection lines to high precision microscopes used in research institutes. These products are used by more than 200,000 customers globally. Products are shipped from Keyence's warehouses in Japan, U.S. (Chicago), UK, Canada, Germany, Italy, France, Thailand, Malaysia, Singapore, and South Korea, or from 148 agents in 31 countries.
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Electrons that strike the phosphor screen cause the phosphor to produce photons of light viewable through the eyepiece lenses. Image intensifiers convert low levels of light photons into electrons, amplify those electrons, and then convert the electrons back into photons of light. Photons from a low-light source enter an objective lens which focuses an image into a photocathode. The photocathode releases electrons via the photoelectric effect as the incoming photons hit it.
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The Michelson interferometer is a common configuration for optical interferometry and was invented by Albert Abraham Michelson. Using a beam splitter, a light source is split into two arms. Each of those light beams is reflected back toward the beamsplitter which then combines their amplitudes using the superposition principle. The resulting interference pattern that is not directed back toward the source is typically directed to some type of photoelectric detector or camera.
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Tigerstedt also continued developing the electrophtalmoscope. The prototype consisted of vibrating mirrors in both the sending and receiving apparatus, using the photoelectric properties of a selenium element at the sender and a light source at the receiving end which was modulated using a Faraday device. The received picture was supposed to be displayed on a movie screen. Two electrophtalmoscopes were built and an experiment was conducted using an electrical cable running from London to Berlin.
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While there he used a visual photometer at Laws Observatory to study variable stars. In 1922 he left Missouri, frustrated at an inability to obtain a more modern observatory. After a year as Kellogg Fellow at Lick Observatory in California, he was appointed Professor of Astronomy and Director of the University of Illinois Observatory in 1923. While at Lick, he used the photoelectric photometer on the 12-inch telescope to study u Herculis.
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The photoelectric effect. Incoming photons on the left strike a metal plate (bottom), and eject electrons, depicted as flying off to the right. While Planck had solved the ultraviolet catastrophe by using atoms and a quantized electromagnetic field, most contemporary physicists agreed that Planck's "light quanta" represented only flaws in his model. A more-complete derivation of black-body radiation would yield a fully continuous and "wave-like" electromagnetic field with no quantization.
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Joel Stebbins (July 30, 1878 – March 16, 1966) was an American astronomer who pioneered photoelectric photometry in astronomy. He was director of the University of Illinois Observatory from 1903 to 1922 where he performed innovative work with the selenium cell. In 1922 he became director of the Washburn Observatory at the University of Wisconsin–Madison where he remained until 1948. After 1948, Stebbins continued his research at Lick Observatory until his final retirement in 1958.
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Kunz's photoelectric cells were many times more sensitive than what was available commercially and therefore able to detect faint star light. In 1915, Stebbins used the new photometers to examine Beta Lyrae, a more irregular binary system. The new equipment allowed observations of increasingly faint stars. Stebbins work was recognized with the American Academy of Arts and Sciences' Rumford Prize in 1913, and the United States National Academy of Sciences' Henry Draper Medal in 1915.
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He has been one of the featured scientists on the occasion of Albert Einstein Annus Mirabilis at U.S. Department of Energy (WYP'05) in connection to his work on photoelectric effect based spectroscopy of quantum states of matter. He also served on the Einstein Annus Mirabilis committee at Princeton University. Hasan's research is focused on fundamental condensed matter physics - either searching for, or in-depth exploration of novel phases of electronic matter.
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In 1962 he co-discovered the comet Seki-Lines. In 1992 he and his wife won the Amateur Achievement Award of the Astronomical Society of the Pacific for their work in the field of photoelectric photometry of variable stars. Short time after he was awarded, Richard Lines died. In 1994 the I.A.P.P.P. announced that its annual Special Award in Astronomy would carry his name as the Richard D. Lines Special Award in Astronomy.
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Attenuation decreases the intensity of electromagnetic radiation due to absorption or scattering of photons. Attenuation does not include the decrease in intensity due to inverse-square law geometric spreading. Therefore, calculation of the total change in intensity involves both the inverse-square law and an estimation of attenuation over the path. The primary causes of attenuation in matter are the photoelectric effect, compton scattering, and, for photon energies of above 1.022 MeV, pair production.
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He was at the time serving as a professor and researcher in the University of Chicago physics department. It is there that he organized and performed his famous oil-drop experiment, which provided the most accurate measure of the time of the electrical charge of an electron. He also established experimental apparatus that was used to confirm the photoelectric effect postulated by Albert Einstein in 1905. For these works Millikan was awarded the 1923 Nobel Prize in Physics.
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The rectifying properties of selenium, amongst other semiconductors, were observed by Braun, Schuster and Siemens between 1874 and 1883.books.google.co.uk The photoelectric and rectifying properties of selenium were also observed by Adams and Day in 1876books.google.co.uk and C. E. Fitts around 1886, but practical rectifier devices were not manufactured routinely until the 1930s. Compared with the earlier copper-oxide rectifier, the selenium cell could withstand higher voltage, but at a lower current capacity per unit area.
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It contains a light source in a light-sensitive electric sensor, which is positioned at a 90-degree angles to the sensor. Normally, light from the light source shoots straight across and misses the sensor. When smoke enters the chamber, it scatters the light, which then hits the sensor and triggers the alarm. Photoelectric smoke detectors typically respond faster to a fire in its early, smoldering stage – before the source of the fire bursts into flames.
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The distance was not close enough to trigger the photoelectric sensor. The probe continued transmitting radiation data for 82.5 hours, to a distance of , and reached perihelion on 18 March 1959 at 01:00 GMT. The cylindrical fourth stage casing (173 cm long, 15 cm diameter, 4.65 kg) went into orbit with the probe. The communication system had worked well, and it was estimated that signals could have been received out to had there been enough battery power.
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Alfred Jost Alfred Jost (born January 2, 1957) is a German inventor and entrepreneur. He is the founder of Solar Bankers and the inventor of a patented concentrating technology solar module."Wipo Publishes Patent of Jost Alfred for 'Solar Module' (American Inventor)". US Fed News Service, January 11, 2013, via Highbeam (subscription required)"Photoelectric solar cell array - US 4418238 A". Google Patents, Mr. Jost is an international expert in the solar market, market economy and corporate business.
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Nellis Solar Power Plant in Nevada, United States Solar energy can be turned into electricity either directly in solar cells, or in a concentrating solar power plant by focusing the light to run a heat engine. A solar photovoltaic power plant converts sunlight into direct current electricity using the photoelectric effect. Inverters change the direct current into alternating current for connection to the electrical grid. This type of plant does not use rotating machines for energy conversion.
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1 The fair's opening night began with a nod to the heavens. Lights were automatically activated when the rays of the star Arcturus were detected. The star was chosen as its light had started its journey at about the time of the previous Chicago world's fair—the World's Columbian Exposition—in 1893. The rays were focused on photoelectric cells in a series of astronomical observatories and then transformed into electrical energy which was transmitted to Chicago.
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The limit describes several loss mechanisms that are inherent to any solar cell design. The first are the losses due to blackbody radiation, a loss mechanism that affects any material object above absolute zero. In the case of solar cells at standard temperature and pressure, this loss accounts for about 7% of the power. The second is an effect known as "recombination", where the electrons created by the photoelectric effect meet the electron holes left behind by previous excitations.
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From that time to the 1920s, physicists were seeking to explain atomic spectra and blackbody radiation. One attempt to explain hydrogen spectral lines was the Bohr atom model. Experiments including electromagnetic radiation and matter - such as the photoelectric effect, Compton effect, and spectra of sunlight the due to the unknown element of Helium, the limitation of the Bohr model to Hydrogen, and numerous other reasons, lead to an entirely new mathematical model of matter and light: quantum mechanics.
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Baird invented some of the first experimental television systems. In 1924 he developed a mechanical television system to transmit moving images by means of electrical signals, which he demonstrated on 25 March 1925 at a London department store, Selfridges. It consisted of a spinning disk set with a spiral pattern of 30 lenses. As each lens rotated past the illuminated subject, it focused the light from a spot on the subject on a selenium photoelectric cell.
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The University of Illinois Observatory. The Observatory is located south of Smith Hall and north of the Morrow Plots. The building was designated as the National Historic Landmark by the Department of the Interior in 1989 as the birthplace in the early 1900s of photoelectric photometry through the work of Dr. Joel Stebbins. The Observatory is the site of frequent Astronomy Open House events and houses a 12-inch refractor telescope available for student and class use.
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A digicon detector is a spatially resolved light detector using the photoelectric effect directly. It uses magnetic and electric fields operating in a vacuum to focus the electrons released from a photocathode by incoming light onto a collection of silicon diodes. It is a photon-counting instrument, so most useful for weak sources. One of digicon's advantages is its very large dynamic range and it results from the short response and decay times of silicon diodes.
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Even after experiments showed that Einstein's equations for the photoelectric effect were accurate, resistance to the idea of photons continued. Einstein's work predicted that the energy of individual ejected electrons increases linearly with the frequency of the light. Perhaps surprisingly, the precise relationship had not at that time been tested. By 1905 it was known that the energy of photoelectrons increases with increasing frequency of incident light and is independent of the intensity of the light.
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Discrete (digital) signals can only take on or off value (1 or 0, true or false). Examples of devices providing a discrete signal include limit switches, photoelectric sensors and encoders. Discrete signals are sent using either voltage or current, where specific extreme ranges are designated as on and off. For example, a controller might use 24 V DC input with values above 22 V DC representing on, values below 2 V DC representing off, and intermediate values undefined.
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The album expanded upon Thighpaulsandra's already extensive instrumental palette, including an autoharp, hurdy-gurdy and the rare photoelectric ANS synthesizer, which allows one to synthesize sounds from artificially drawn soundwaves and images. Other non-musical instruments include a scraper, heard at the end of "Double Vulgar"; and a large wheel similar to the one found on the game show Wheel of Fortune, found in the basement of a church, that forms the basis of "He Tastes of the Sea".
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A new spectrograph was commissioned in 1951 and Wesselink set to work studying the radial velocities of hot, luminous stars in the Milky Way to improve knowledge about the rotation of the disk of the Galaxy. He also carried out photoelectric photometry of stars in the Magellanic Clouds. In collaboration with A. D. Thackeray, he discovered RR Lyrae variable stars in the Magellanic Clouds, which provided much improved measurements of the distances to these two nearby galaxies.
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Electrons can transfer between different orbitals by the emission or absorption of photons with an energy that matches the difference in potential. Other methods of orbital transfer include collisions with particles, such as electrons, and the Auger effect. To escape the atom, the energy of the electron must be increased above its binding energy to the atom. This occurs, for example, with the photoelectric effect, where an incident photon exceeding the atom's ionization energy is absorbed by the electron.
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A combination of proximity switches, mechanical switches, photoelectric sensors and timers are all used by the controller to track train movements. Each train consists of four cars with three rows per car, two riders per row, holding 24 total riders. Each row has a lap bar and a seat belt. Until the 2018 season, the lap bar itself was locked and unlocked by an electrical current that activates solenoids on the train, resulting in a "buzzing" electrical sound.
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Moreover, the minimum energy can be misleading in materials where there are no actual electron states at the Fermi level that are available for excitation. For example, in a semiconductor the minimum photon energy would actually correspond to the valence band edge rather than work function. Of course, the photoelectric effect may be used in the retarding mode, as with the thermionic apparatus described above. In the retarding case, the dark collector's work function is measured instead.
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The Moscow Electrovacuum Instrument Plant, with its two associated special design bureaus, specializes in developing and producing a variety of vacuum tube products (photoelectric cells, xenon and mercury tubes, gas-filled and gas discharge devices, photoelectronic multipliers and others). This plant dates back to before World War II, and was known, until 1972, as the Moscow Electric Lamp Plant (MELZ). The Khromatron Plant in Moscow and the Electrovacuum Instrument Plant in Voronezh, produce mainly CRTs for color television.
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The telescope provided a 10°x10° field of view with photographic plates and could be equipped with an objective prism for low-resolution mass spectroscopic observations. The large field-of-view led to numerous supernova and asteroid discoveries at the time. In 1966, a smaller, 0.5 m Cassegrain telescope with a two-channel photoelectric photometer was installed. Finally, a 1 m Ritchey-Chrétien-coudé (RCC) telescope was installed in 1974, for high-resolution imaging and photometry of fainter targets.
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Several copies of this system have been made in JAXA and NASA, and the original system has been transferred to California Institute of Technology with an upgraded setup of tetrahedra four beam laser heating system. On the Moon the photoelectric effect and electrons in the solar wind charge fine layers of moon dust on the surface forming an atmosphere of dust that floats in "fountains" over the surface of the moon.Bell, Trudy E., "Moon fountains", FirstScience.com, 2001-01-06.
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The non-resonant inelastic x-ray scattering cross section is orders of magnitude smaller than that of photoelectric absorption. Therefore, high-brilliance synchrotron beamlines with efficient spectrometers that are able to span a large solid angle of detection are required. XRS spectrometers are usually based on spherically curved analyzer crystals that act as focusing monochromator after the sample. The energy resolution is on the order of 1 eV for photon energies on the order of 10 keV.
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Aneutronic fusion produces energy in the form of charged particles instead of neutrons. This means that energy from aneutronic fusion could be captured using direct conversion instead of the steam cycle that is used for neutrons. Direct conversion techniques can either be inductive, based on changes in magnetic fields, electrostatic, based on pitting charged particles against an electric field, or photoelectric, in which light energy is captured. In a pulsed mode, inductive techniques could be used.
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This 12.3 megapixel resolution is interpolated from the approximately 6 million photodiodes on the Fujifilm 4th generation Super CCD HR sensor. While still a Bayer filter CCD with 3 million green, 1.5 million each red and blue photodiodes, the SuperCCD HR array is tilted 45 degrees. Fujifilm states that its larger equilateral octagonal photodiodes, tilted arrangement, and use of the photoelectric sensing capability of CCD vertical transfer paths enable 12 million output pixels. It has dual memory slots.
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Two different types of phototubes A phototube or photoelectric cell is a type of gas-filled or vacuum tube that is sensitive to light. Such a tube is more correctly called a 'photoemissive cell' to distinguish it from photovoltaic or photoconductive cells. Phototubes were previously more widely used but are now replaced in many applications by solid state photodetectors. The photomultiplier tube is one of the most sensitive light detectors, and is still widely used in physics research.
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Phototubes operate according to the photoelectric effect: Incoming photons strike a photocathode, knocking electrons out of its surface, which are attracted to an anode. Thus current is dependent on the frequency and intensity of incoming photons. Unlike photomultiplier tubes, no amplification takes place, so the current through the device is typically of the order of a few microamperes. The light wavelength range over which the device is sensitive depends on the material used for the photoemissive cathode.
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Direct conversion imagers utilize photoconductors, such as amorphous selenium (a-Se), to capture and convert incident x-ray photons directly into electric charge.Direct vs. Indirect Conversion X-ray photons incident upon a layer of a-Se generate electron-hole pairs via the internal photoelectric effect. A bias voltage applied to the depth of the selenium layer draw the electrons and holes to corresponding electrodes; the generated current is thus proportional to the intensity of the irradiation.
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Although he uses a CCD camera, he is also good in visual estimates of star luminosity, reaching an accuracy of 0.03 magnitude (confirmed by separate photoelectric measurements). He has also been acknowledged for his numerous estimates and measurements of brightness and positions of comets and variable stars, as well as position measurements of minor planets. In 1993 he co-discovered (with Jan Kyselý) new variable star ES UMa. He is a member of the Czech Astronomical Society.
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The latter integrates an electronic measurement component and a LCD with a mechanical water meter. Mechanical water meters normally use a reed switch, hall or photoelectric coding register as the signal output. After processing by the microcontroller unit (MCU) in the electronic module, the data are transmitted to the LCD or output to an information management system. Water meters are generally owned, read and maintained by a public water provider such as a city, rural water association or private water company.
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Originally, single channel photoelectric photometry and photography using plates or film were the means of acquiring data. The observatory was closed from 1981 until 1986, at a time when the university was having financial difficulties. It was reopened in the spring of 1986 on the occasion of the return of Comet Halley and has been in regular operation ever since. Since the 1980s, a CCD camera has been employed as the main instrument and the Raytheon computer has been retired.
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He also showed they were identical with particles given off by photoelectric and radioactive materials. It was quickly recognized that they are the particles that carry electric currents in metal wires, and carry the negative electric charge of the atom. Thomson was given the 1906 Nobel prize for physics for this work. Philipp Lenard also contributed a great deal to cathode ray theory, winning the Nobel prize for physics in 1905 for his research on cathode rays and their properties.
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In the active detector layer of photon detectors, incident photons are converted to electron-hole pairs via the photoelectric effect. The resulting charge cloud is being accelerated towards the readout electronics via an applied voltage bias. Because of thermic energy and repulsion due to the electric fields inside such a device, the charge cloud diffuses, effectively getting larger in lateral size. In pixelated detectors, this effect can lead to a detection of parts of the initial charge cloud in neighbouring pixels.
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Experimental confirmation of Maxwell's theory was provided by Hertz, who generated and detected electric waves in 1886 and verified their properties, at the same time foreshadowing their application in radio, television, and other devices. In 1887, Heinrich Hertz discovered the photoelectric effect. Research on the electromagnetic waves began soon after, with many scientists and inventors conducting experiments on their properties. In the mid to late 1890s Guglielmo Marconi developed a radio wave based wireless telegraphy system (see invention of radio).
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1950s TV Remote by Motorola SABA corded TV remote The first remote intended to control a television was developed by Zenith Radio Corporation in 1950. The remote, called "Lazy Bones," was connected to the television by a wire. A wireless remote control, the "Flashmatic," was developed in 1955 by Eugene Polley. It worked by shining a beam of light onto one of four photoelectric cells, but the cell did not distinguish between light from the remote and light from other sources.
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Research institutes and laboratories in the discipline include: Micrometer and Nanometer Technology Research Center, Research Institute of Optoelectronic Information Technology, and Laboratory of Mechatronic Technology. Major research interests include: A. Design and Manufacturing Technology of Precision Instrumentations and Machinery; B. Optoelectronic Instruments and Equipment; C. Internal Structure Detecting Techniques for Industrial Purposes; D. Detecting and Control Technology; E. Inertia Space Sensing; F. Test and Control Technology; G. Advanced Micro-Nano Parts and System Technology; H. Photoelectric Technology; I. Non-destructive Test Technology.
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The photoemission or photoelectric effect is a quantum electronic phenomenon in which electrons (photoelectrons) are emitted from matter after the absorption of energy from electromagnetic radiation such as UV light or X-ray. When UV light or X-ray is absorbed by matter, electrons are excited from core levels into unoccupied states, leaving empty core states. Secondary electrons are generated by the decay of the core hole. Auger processes and inelastic electron scattering create a cascade of low-energy electrons.
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Experimental confirmation of Maxwell's theory was provided by Hertz, who generated and detected electric waves in 1886 and verified their properties, at the same time foreshadowing their application in radio, television, and other devices. In 1887, Heinrich Hertz discovered the photoelectric effect. Research on the electromagnetic waves began soon after, with many scientists and inventors conducting experiments on their properties. In the mid to late 1890s Guglielmo Marconi developed a radio wave based wireless telegraphy system (see invention of radio).
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Andrea Naccari (12 August 1841 - 2 October 1919) is notable for his study of the thermoelectric properties of metals, the photoelectric effect of metals immersed in liquids, and the electrical conductivity of gases and liquid dielectrics. He showed that the variation in the electrical resistance of distilled water was due largely to the solubility of the glass of the receptacle in which it was contained. He obtained his PhD in pure maths in 1862 at the University of Padua under Francesco Rossetti.
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Common detector materials include sodium iodide (NaI) scintillation counters and high-purity germanium detectors. To accurately determine the energy of the gamma ray, it is advantageous if the photoelectric effect occurs, as it absorbs all of the energy of the incident ray. Absorbing all the energy is also possible when a series of these interaction mechanisms take place within the detector volume. With Compton interaction or pair production, a portion of the energy may escape from the detector volume, without being absorbed.
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Retrieved 28 May 2019 His first employment in industry was at G. Hasler Ltd. in Berne, Switzerland. In 1963, he emigrated to the US and worked for Ampex Corporation in Redwood City in the field of magnetic-tape data storage devices. When he returned to Switzerland in 1968, he joined the newly founded Corporate Research Center of Brown, Boveri & Cie in Baden AG. His first assignment was the development of a photoelectric current sensor for high-voltage transmission lines using the Faraday effect.
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AS-Interface was developed during the late 1980s and early 1990s by a development partnership of 11 companies mostly known for their offering of industrial non-contact sensing devices like inductive sensors, photoelectric sensors, capacitive sensors and ultrasonic sensors. Once development was completed the consortium was resolved and a member organization, AS-International, was founded. The first operational system was shown at the 1994 Hanover fair. In 2018, a new technology step was presented at SPS IPC Drives in Nuremberg.
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Albert Einstein in 1905 explained of the photoelectric effect; a particle description of light as photons. In 1916, Sommerfeld explains fine structure; the splitting of the spectral lines of atoms due to first order relativistic corrections. The Compton effect of 1923 provided more evidence that special relativity does apply; in this case to a particle description of photon–electron scattering. de Broglie extends wave–particle duality to matter: the de Broglie relations, which are consistent with special relativity and quantum mechanics.
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Potential uses for MoTe2 are for lubricant, electronics, optoelectronics or a photoelectric cell material. Diodes have been fabricated from MoTe2 by baking a p-type material in bromine. The diode's current versus voltage plot shows very little current with reverse bias, an exponential region with dV/dln(j) of 1.6, and at higher voltages (>0.3V) a linear response due to resistance. When operated as a capacitor, the capacitance varies as the inverse square of the bias, and also drops for higher frequencies.
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The potassium intercalated molybdenum ditelluride becomes superconducting below 2.8 K. As a lubricant molybdenum ditelluride can function well in a vacuum and at temperatures up to 500 °C with a coefficient of friction below 0.1. However molybdenum disulfide has a lower friction, and molybdenum diselenide can function at higher temperatures. Related dichalcogenides can be fabricated into fairly efficient photoelectric cells. Potentially, stacked monolayers of indium nitride and molybdenum ditelluride can result in improved properties for photovoltaics, including lower refractive index, and greater absorbance.
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Gamma rays are photons, whose absorption cannot be described by LET. When a gamma quantum passes through matter, it may be absorbed in a single process (photoelectric effect, Compton effect or pair production), or it continues unchanged on its path. (Only in the case of the Compton effect, another gamma quantum of lower energy proceeds). Gamma ray absorption therefore obeys an exponential law (see Gamma rays); the absorption is described by the absorption coefficient or by the half-value thickness.
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They arranged metals with respect to their power of discharging negative electricity: rubidium, potassium, alloy of potassium and sodium, sodium, lithium, magnesium, thallium and zinc; for copper, platinum, lead, iron, cadmium, carbon, and mercury the effects with ordinary light were too small to be measurable. The order of the metals for this effect was the same as in Volta's series for contact-electricity, the most electropositive metals giving the largest photo-electric effect. The gold leaf electroscope to demonstrate the photoelectric effect.
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When photogenerated electrons and holes have different mobilities, a potential difference can be created between the illuminated and non-illuminated faces of a semiconductor slab.S. M. Ryvkin, Photoelectric Effects in Semiconductors, page 296, (Consultants Bureau, New York, 1964). Generally this potential is created through the depth of the slab, whether it is a bulk semiconductor or a polycrystalline film. The difference between these cases is that in the latter, a photovoltage can be created in each one of the microcrystallites.
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Arlo Udell Landolt (born September 29, 1935) is an American astronomer. Landolt has worked principally in photometry and has published a number of widely used listsUBVRI photometric standard stars around the celestial equator, Arlo U. Landolt, Astronomical Journal, 88, #3 (March 1983), pp. 439–460.UBV photoelectric sequences in the celestial equatorial selected areas 92-115, Arlo U. Landolt, Astronomical Journal, 78, #9 (November 1973), pp. 959–981.UBVRI photometric standard stars in the magnitude range 11.5 of standard stars.
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The standard measure of speed is cards per minute, abbreviated CPM: The number of cards which can be read or punched in one minute. Card reader models vary from 300 to around 2,000 CPM. If all columns of an 80 column card encode information this translates to approximately 2,500 characters per second (CPS). Cards may be read using mechanical brushes that make an electrical contact for a hole, and no contact if no punch, or photoelectric sensors that function similarly.
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The Born rule was formulated by Born in a 1926 paper. In this paper, Born solves the Schrödinger equation for a scattering problem and, inspired by Einstein's work on the photoelectric effect, concludes, in a footnote, that the Born rule gives the only possible interpretation of the solution. In 1954, together with Walther Bothe, Born was awarded the Nobel Prize in Physics for this and other work. John von Neumann discussed the application of spectral theory to Born's rule in his 1932 book.
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They are being tested for a number of other automotive uses including ultrasonic people detection and assisting in autonomous UAV navigation. Because ultrasonic sensors use sound rather than light for detection, they work in applications where photoelectric sensors may not. Ultrasonics are a great solution for clear object detection and for liquid level measurement, applications that photoelectrics struggle with because of target translucence. As well, target color or reflectivity do not affect ultrasonic sensors, which can operate reliably in high-glare environments.
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300x300px Photoemission spectroscopy (PES), also known as photoelectron spectroscopy, refers to energy measurement of electrons emitted from solids, gases or liquids by the photoelectric effect, in order to determine the binding energies of electrons in the substance. The term refers to various techniques, depending on whether the ionization energy is provided by X-ray photons or ultraviolet photons. Regardless of the incident photon beam, however, all photoelectron spectroscopy revolves around the general theme of surface analysis by measuring the ejected electrons.
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Quartz photoelectric spectrophotometer, Cary & Beckman, 1941 The A, B, and C prototype models all coupled an external Beckman pH meter to the optical component to obtain readouts. In developing the Model D, Beckman took the direct-coupled amplifier circuit from the pH meter and combined the optical and electronic components in a single housing, making it more economical. Moving from a prototype to production of the Model D involved challenges. Beckman originally approached Bausch and Lomb about making quartz prisms for the spectrophotometer.
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These speed changes can be caused by Bremsstrahlung radiation or cyclotron radiation or synchrotron radiation or electric field interactions. The radiation can be estimated using the Larmor formula and comes in the X-ray, IR, UV and visible spectrum. Some of the energy radiated as X-rays may be converted directly to electricity. Because of the photoelectric effect, X-rays passing through an array of conducting foils transfer some of their energy to electrons, which can then be captured electrostatically.
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Established in April 1993, the zone enjoys all the preferential policies stipulated for economic and technological development zones of coastal open cities. The total area of CETDZ is , of which has been set aside for development and utilization. It is located from downtown Changchun, from the freight railway station and from the Changchun international airport. The zone is devoted to developing five leading industries: namely automotive parts and components, photoelectric information, bio-pharmaceutical, fine processing of foods, and new building materials.
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Because the web may be fragile — particularly at its edge — non-contact sensors are used. Sensors developed for Web Guiding applications in the Converting Industry may be pneumatic, photoelectric, ultrasonic, or infrared. The system’s controls must process the output signals from the sensors in to a form that can drive an actuator. Many controls today are electronic, typically using an amplifier to convert signals from the sensor, then commanding a special servo motor incorporating a lead or ball screw for guiding actuation.
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Beginning in 1912, he spent several years investigating and finally proving Albert Einstein's proposed linear relationship between energy and frequency, and providing the first direct photoelectric support for Planck's constant. In 1923 Millikan was awarded the Nobel Prize for Physics. In 1909, S. P. L. Sørensen invented the pH concept and develops methods for measuring acidity. In 1911, Antonius Van den Broek proposed the idea that the elements on the periodic table are more properly organized by positive nuclear charge rather than atomic weight.
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A variety of upgrades and innovations were applied to the light in the early twentieth century, including an experimental photoelectric control for the fog signal installed in 1936. The characteristic was altered several times as well. Red sectors in the lantern glass showed a white sector until the entire signal was made flashing red. Upon automation in 1972 the keeper's house was transferred to the U.S. Army, which used it as a dwelling for Fort Monroe's Command Sergeant Major until the fort was closed in 2011.
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The differencing calculator with recording (German:Differenzen Rechengereat, English:Differencing Calculating Apparatus) was a machine designed to compute a flag of difference for a set of enciphered code groups and record them. It consisted of two teleprinter tapes with photoelectric reading heads, a set of calculating relays and a recording electric teleprinter. The read heads operated at seven characters a second, bounded by the speed of the teleprinter where time was lost by the carriage return and line feed. It cost ℛℳ920 Reichsmarks, $800.00 at 1945 conversion rates.
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This led to considerable theoretical work to explain the propagation of light without an aether. A major breakthrough was the theory of relativity, which could explain why the experiment failed to see aether, but was more broadly interpreted to suggest that it was not needed. The Michelson- Morley experiment, along with the blackbody radiator and photoelectric effect, was a key experiment in the development of modern physics, which includes both relativity and quantum theory, the latter of which explains the particle-like nature of light.
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For Einstein, the Lorentz transformation implied a conceptual change: that the concept of position in space or time was not absolute, but could differ depending on the observer's location and velocity. Moreover, in another paper published the same month in 1905, Einstein made several observations on a then-thorny problem, the photoelectric effect. In this work he demonstrated that light can be considered as particles that have a "wave-like nature". Particles obviously do not need a medium to travel, and thus, neither did light.
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Photoelectric beam system detect the presence of an intruder by transmitting visible or infrared light beams across an area, where these beams may be obstructed. To improve the detection surface area, the beams are often employed in stacks of two or more. However, if an intruder is aware of the technology's presence, it can be avoided. The technology can be an effective long-range detection system, if installed in stacks of three or more where the transmitters and receivers are staggered to create a fence-like barrier.
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Pioneer 4 was an American spin-stabilized uncrewed spacecraft launched as part of the Pioneer program on a lunar flyby trajectory and into a heliocentric orbit making it the first probe of the United States to escape from the Earth's gravity. It carried a payload similar to Pioneer 3: a lunar radiation environment experiment using a Geiger–Müller tube detector and a lunar photography experiment. It passed within 58,983 km of the Moon's surface. However, Pioneer 4 did not come close enough to trigger its photoelectric sensor.
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Photoelectric eyes measure the amount of sun coming into the space and increase or decrease the fluorescent lighting to balance the light levels in the office. Occupancy/motion sensors turn lights on and off in conference spaces and the lights are programmed to turn off automatically at night and on weekends. These strategies reduce the wattage per square foot to 35% below the baseline of one watt per square foot. Only one elevator was integrated into the building, an energy-efficient but slow model.
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Photonics is at the core of light-harvesting concepts and technologies like photovoltaics and solar cells. To tackle the challenges in energy efficiency, researchers at ICFO are developing new approaches to renewable energy applications. Examples of on-going projects include low-cost highly efficient transparent solar cells, organic LEDs, transparent photonic devices, smart windows, energy efficient optoelectronic devices, photoelectric, thermoelectric and electromechanical transducers, and energy efficient sensors. The center also performs research in nanophotonics, such as nano- structured materials, nano-cavities, nano-antennas, and nano-photonic devices.
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Oseen was a member of the Royal Swedish Academy of Sciences from 1921, and a member of the Academy's Nobel Prize committee for physics from 1922. As a full professor of a Swedish university, Oseen also had the right to nominate Nobel Prize winners. Oseen nominated Albert Einstein for the Nobel Prize in 1921, for Einstein's work on the photoelectric effect (rather than the more controversial theory of general relativity). Einstein was finally awarded the prize for 1921 when Oseen repeated the nomination in 1922.
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Typical paper tapes showing holes punched to input data to early computers. The newly graduated Berdichevsky studied computing from the visiting English software engineer Cicely Popplewell (famous for having worked with Alan Turing in Manchester) and with the Spanish mathematician Ernesto García Camarero. Popplewell herself motivated Berdichevsky to write and run the first program for the new computer, which required multiple arithmetic calculations. A photoelectric device read a punched paper ribbon that was used to submit the data and Clementina produced the desired result in only seconds.
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The attenuation coefficient is compiled from all the cross sections of the interactions that are happening in the material. The three most important inelastic interactions with X-rays at those energy levels are the photoelectric effect, compton scattering and pair production. After having crossed the object, the photons are captured by a detector, such as a silver halide film, a phosphor plate or flat panel detector. When an object is too thick, too dense, or its effective atomic number is too high, a linac can be used.
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In other words, Planck then contemplated virtual oscillators. In 1905, Albert Einstein adapted the Planck postulate to explain the photoelectric effect, but Einstein proposed that the energy of photons themselves was quantized (with photon energy given by the Planck-Einstein relation), and that quantization was not merely a feature of microscopic oscillators. Planck's postulate was further applied to understanding the Compton effect, and was applied by Niels Bohr to explain the emission spectrum of the hydrogen atom and derive the correct value of the Rydberg constant.
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Gamma spectroscopy detectors are passive materials that are able to interact with incoming gamma rays. The most important interaction mechanisms are the photoelectric effect, the Compton effect, and pair production. Through these processes, the energy of the gamma ray is absorbed and converted into a voltage signal by detecting the energy difference before and after the interaction (or, in a scintillation counter, the emitted photons using a photomultiplier). The voltage of the signal produced is proportional to the energy of the detected gamma ray.
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For direct RIXS to occur, both photoelectric transitions—the initial one from core to valence state and succeeding one to fill the core hole—must be possible. These transitions can for instance be an initial dipolar transition of 1s → 2p followed by the decay of another electron in the 2p band from 2p → 1s. This happens at the K-edge of oxygen, carbon and silicon. A very efficient sequence often used in 3d transition metals is a 1s → 3d excitation followed by a 2p → 1s decay.
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The nitrogen-vacancy center in diamond has attracted a lot of research in the past decade due to its excellent performance in optical nanophotonic devices. In a recent experiment, electromagnetically induced transparency was implemented on a multi-pass diamond chip to achieve full photoelectric magnetic field sensing. Despite these closely related experiments, optical storage has yet to be implemented in practice. The existing nitrogen-vacancy center (negative charge and neutral nitrogen-vacancy center) energy level structure makes the optical storage of the diamond nitrogen-vacancy center possible.
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This converted the brightness of the image at each spot into a proportional electric signal, which could be sent to a receiver by radio waves. As each lens swept past the subject, it scanned a successive line of the image. At the receiver, a light shining through the holes in a similar rotating disk recreated an image of the subject. Due to the low sensitivity of the photoelectric cells, Baird's first system was not able to televise human faces, because they had inadequate contrast.
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Didier Queloz and Michel Mayor at the La Silla Observatory (2012). Mayor's research interests include extrasolar planets (also known as exoplanets), instrumentation, statistical properties of double stars, globular cluster dynamics, galactic structure and kinematics. Mayor's doctoral thesis at the University of Geneva was devoted to the spiral structure of galaxies. During his time as a research associate, there had been strong interest in developing photoelectric-based Doppler spectrometers to obtain more accurate measurements of radial velocities of stellar objects compared to existing photographic methods.
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Beginning in 1912, he spent several years investigating and finally proving Albert Einstein's proposed linear relationship between energy and frequency, and providing the first direct photoelectric support for Planck's constant. In 1923 Millikan was awarded the Nobel Prize for Physics. In 1909, S. P. L. Sørensen invented the pH concept and developed methods for measuring acidity. In 1911, Antonius Van den Broek proposed the idea that the elements on the periodic table are more properly organized by positive nuclear charge rather than atomic weight.
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Those observations were published in the international media, making Einstein world-famous. On 7 November 1919, the leading British newspaper The Times printed a banner headline that read: "Revolution in Science – New Theory of the Universe – Newtonian Ideas Overthrown". In 1920, he became a Foreign Member of the Royal Netherlands Academy of Arts and Sciences. In 1922, he was awarded the 1921 Nobel Prize in Physics "for his services to Theoretical Physics, and especially for his discovery of the law of the photoelectric effect".
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While the general theory of relativity was still considered somewhat controversial, the citation also does not treat even the cited photoelectric work as an explanation but merely as a discovery of the law, as the idea of photons was considered outlandish and did not receive universal acceptance until the 1924 derivation of the Planck spectrum by S. N. Bose. Einstein was elected a Foreign Member of the Royal Society (ForMemRS) in 1921. He also received the Copley Medal from the Royal Society in 1925.
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Newspaper headline on 4 May 1935 Einstein played a major role in developing quantum theory, beginning with his 1905 paper on the photoelectric effect. However, he became displeased with modern quantum mechanics as it had evolved after 1925, despite its acceptance by other physicists. He was skeptical that the randomness of quantum mechanics was fundamental rather than the result of determinism, stating that God "is not playing at dice". Until the end of his life, he continued to maintain that quantum mechanics was incomplete.
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The development of the photoelectric method for investigating weakly variable stars and spectroscopic investigations with the 122 cm telescope made the Babelsberg observatory well-known beyond Europe, too. At the beginning of 1931 the Sonneberg Observatory founded by Cuno Hoffmeister was attached to the Babelsberg Observatory. For more than 60 years a photographic sky survey was carried out, which represents the second largest archive of astronomical photographic plates. This archive and the discovery and investigation of variable stars popularized the name Sonneberg all over the astronomical world.
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Xeromammography is a photoelectric method of recording an x-ray image on a coated metal plate, using low-energy photon beams, long exposure time, and dry chemical developers. It is a form of xeroradiography. Radiation exposure is an important factor in risk assessment since it makes up 98% of the effective dose. Currently, the mean value of the absorbed dose in the glandular tissue is used as a description of radiation risk since th e glandular tissue is the most vulnerable part of the breast.
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However, the manner of the increase was not experimentally determined until 1914 when Robert Andrews Millikan showed that Einstein's prediction was correct. The photoelectric effect helped to propel the then-emerging concept of wave–particle duality in the nature of light. Light simultaneously possesses the characteristics of both waves and particles, each being manifested according to the circumstances. The effect was impossible to understand in terms of the classical wave description of light,Resnick, Robert (1972) Basic Concepts in Relativity and Early Quantum Theory, Wiley, p.
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Photons hitting a thin film of alkali metal or semiconductor material such as gallium arsenide in an image intensifier tube cause the ejection of photoelectrons due to the photoelectric effect. These are accelerated by an electrostatic field where they strike a phosphor coated screen, converting the electrons back into photons. Intensification of the signal is achieved either through acceleration of the electrons or by increasing the number of electrons through secondary emissions, such as with a micro-channel plate. Sometimes a combination of both methods is used.
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High-energy X-rays were applied to ionize gas particles and observe photoelectric electrons. The observation of electron tracks that were independent of the frequency of the incident photon suggested a mechanism for electron ionization that was caused from an internal conversion of energy from a radiationless transition. Further investigation, and theoretical work using elementary quantum mechanics and transition rate/transition probability calculations, showed that the effect was a radiationless effect more than an internal conversion effect."The Auger Effect and Other Radiationless Transitions".
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Photometric-standard stars are a series of stars that have had their light output in various passbands of photometric system measured very carefully. Other objects can be observed using CCD cameras or photoelectric photometers connected to a telescope, and the flux, or amount of light received, can be compared to a photometric-standard star to determine the exact brightness, or stellar magnitude, of the object. A current set of photometric-standard stars for UBVRI photometry was published by Arlo U. Landolt in 1992 in the Astronomical Journal.
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James Cuffey (October 8, 1911 – May 30, 1999) was an American astronomer. He specialized in photoelectric photometry and held the patent on the Cuffey Iris Photometer,United States Patent No. 3186295 an instrument used in stellar photographic photometry. Born in Chicago, Illinois, Cuffey became a graduate student at Northwestern University in 1934, then went on to Harvard University as a doctoral student under Harlow Shapley. He received his Ph.D. from Harvard in 1938, then took a position as a postdoctoral fellow at Indiana University.
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The first, PE Spaniel, used the original photoelectric guidance system. The cell was mounted in a pod at the end of one of the wings and sent control inputs to the movable rear-mounted fins. The second, RDF Spaniel, used beam riding using the signal from the GL Mark III radar sets. In testing, it was found that the energy needed to manoeuvre the rocket in flight greatly limited its range, to the point where it was no longer able to effectively reach target altitudes.
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During World War I the regiment mobilized two more railway engineer battalions, twelve railway construction companies, one railway operations battalion, four decauville companies, and 177 photoelectric sections, which operated searchlights along the Italian Front. During the conflict the regiment's units built of railway, of decauville trench railways and 144 bridges. The regiment began to operate the Chivasso–Ivrea–Aosta railway in 1915 and after World War I it also began to operate the Bolzano- Meran-Mals railway in the newly annexed province of South Tyrol.
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Design of a PSD using a PIN diode The technical term PSD was first used in a 1957 publication by J.T. Wallmark for lateral photoelectric effect used for local measurements. On a laminar semiconductor, a so-called PIN diode is exposed to a tiny spot of light. This exposure causes a change in local resistance and thus electron flow in four electrodes. From the currents I_a, I_b, I_c and I_d in the electrodes, the location of the light spot is computed using the following equations.
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Non-thermionic types, such as a vacuum phototube however, achieve electron emission through the photoelectric effect, and are used for such purposes as the detection of light intensities. In both types, the electrons are accelerated from the cathode to the anode by the electric field in the tube. The simplest vacuum tube, the diode, invented in 1904 by John Ambrose Fleming, contains only a heated electron-emitting cathode and an anode. Electrons can only flow in one direction through the device—from the cathode to the anode.
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X-rays interact with matter in three main ways, through photoabsorption, Compton scattering, and Rayleigh scattering. The strength of these interactions depends on the energy of the X-rays and the elemental composition of the material, but not much on chemical properties, since the X-ray photon energy is much higher than chemical binding energies. Photoabsorption or photoelectric absorption is the dominant interaction mechanism in the soft X-ray regime and for the lower hard X-ray energies. At higher energies, Compton scattering dominates.
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He published papers and books on the subjects of x-ray crystallography, materials science, planet formation, mathematics, imaging, time, probability&statistics;, colour vision and astrophysics. Woolfson was active in research and scientific writing for nearly 70 years; his first paper was published in 1951 M M Woolfson, A Photoelectric Structure-Factor Machine, Acta. Cryst. (1951), 4, 250-253 and his last book on stars M M Woolfson, About Stars, World Scientific Publishing Company, July 2019 was published in July 2019, a few months before he died.
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In 1877, Minchin began work on using photoelectricity with a view to transmitting images. Four years earlier, Willoughby Smith had discovered the photoelectric effect on selenium rods; Minchin became skilled at creating photovoltaic cells made from selenium. His idea was to have a bundle of many insulated wires in parallel, their ends light-sensitised with selenium to detect an image, and for the far ends to emit a proportional level of light registered by a photographic film, effectively as pixels. The efforts were unsuccessful.
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When the required steel had been formed, it was poured into ladles and then transferred into moulds while the lighter slag was left behind. The conversion process, called the "blow", was completed in approximately 20 minutes. During this period the progress of the oxidation of the impurities was judged by the appearance of the flame issuing from the mouth of the converter. The modern use of photoelectric methods of recording the characteristics of the flame greatly aided the blower in controlling final product quality.
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Lawrence followed Swann to the University of Chicago, and then to Yale University in New Haven, Connecticut, where Lawrence completed his Doctor of Philosophy (Ph.D.) degree in physics in 1925 as a Sloane Fellow, writing his doctoral thesis on the photoelectric effect in potassium vapor. He was elected a member of Sigma Xi, and, on Swann's recommendation, received a National Research Council fellowship. Instead of using it to travel to Europe, as was customary at the time, he remained at Yale University with Swann as a researcher.
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Robert Millikan and Albert Einstein at the California Institute of Technology in 1932 When Einstein published his seminal 1905 paper on the particle theory of light, Millikan was convinced that it had to be wrong, because of the vast body of evidence that had already shown that light was a wave. He undertook a decade-long experimental program to test Einstein's theory, which required building what he described as "a machine shop in vacuo" in order to prepare the very clean metal surface of the photo electrode. His results published in 1914 confirmed Einstein's predictions in every detail, but Millikan was not convinced of Einstein's interpretation, and as late as 1916 he wrote, "Einstein's photoelectric equation... cannot in my judgment be looked upon at present as resting upon any sort of a satisfactory theoretical foundation," even though "it actually represents very accurately the behavior" of the photoelectric effect. In his 1950 autobiography, however, he simply declared that his work "scarcely permits of any other interpretation than that which Einstein had originally suggested, namely that of the semi-corpuscular or photon theory of light itself".
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Max Planck (1858–1947), the originator of the theory of quantum mechanics Albert Einstein (1879–1955), whose work on the photoelectric effect and the theory of relativity led to a revolution in 20th century physics Modern physics began in the early 20th century with the work of Max Planck in quantum theory and Albert Einstein's theory of relativity. Both of these theories came about due to inaccuracies in classical mechanics in certain situations. Classical mechanics predicted a varying speed of light, which could not be resolved with the constant speed predicted by Maxwell's equations of electromagnetism; this discrepancy was corrected by Einstein's theory of special relativity, which replaced classical mechanics for fast- moving bodies and allowed for a constant speed of light. Black-body radiation provided another problem for classical physics, which was corrected when Planck proposed that the excitation of material oscillators is possible only in discrete steps proportional to their frequency; this, along with the photoelectric effect and a complete theory predicting discrete energy levels of electron orbitals, led to the theory of quantum mechanics taking over from classical physics at very small scales.
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W. Irvine and colleagues used photoelectric photometry in the 1960s. Some of these early data were analyzed by G. de Vaucouleurs, summarized by D. Harris and used for predicting apparent magnitudes in the Astronomical Almanac for several decades. Highly accurate new observations covering the widest range of phase angles to date (2 to 170°) were carried out by A. Mallama, D. Wang and R. Howard using the Large Angle and Spectrometric Coronograph (LASCO) on the Solar and Heliospheric Observatory (SOHO) satellite. They also obtained new CCD observations from the ground.
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The cameras were named LWP, LWR, SWP and SWR where P stands for prime, R for redundant and LW/SW for long/short wavelength. The cameras were television cameras, sensitive only to visible light, and light gathered by the telescope and spectrographs first fell on a UV-to-visible converter. This was a caesium-tellurium cathode, which was inert when exposed to visible light, but which gave off electrons when struck by UV photons due to the photoelectric effect. The electrons were then detected by the TV cameras.
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This insight united the nascent fields of electromagnetic theory with optics and led directly to a complete description of the electromagnetic spectrum. However, attempting to reconcile electromagnetic theory with two observations, the photoelectric effect, and the nonexistence of the ultraviolet catastrophe, proved troublesome. Through the work of leading theoretical physicists, a new theory of electromagnetism was developed using quantum mechanics. This final modification to electromagnetic theory ultimately led to quantum electrodynamics (or QED), which fully describes all electromagnetic phenomena as being mediated by wave–particles known as photons.
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He received a B.S. degree in physics from Villanova University in 1964 and his doctoral degree in astronomy from the University of Pennsylvania in 1970. His research interests are binary star systems, pulsating stars, black holes, evolution of the sun and solar-like stars, pulsating red stars, APT (Automatic Photoelectric Telescope) programs, apsidal motion studies, and searching for exoplanets. More recently, Guinan has been involved with a Mars Garden project, which studies the growth of plants in replicated Martian soil. He was elected a Legacy Fellow of the American Astronomical Society in 2020.
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Although an intruder alarm panel may also have these detectors connected, it may not meet all the local fire code requirements of a fire alarm system. Traditional smoke detectors are technically ionisation smoke detectors which create an electric current between two metal plates, which sound an alarm when disrupted by smoke entering the chamber. Ionisation smoke alarms can quickly detect the small amounts of smoke produced by fast-flaming fires, such as cooking fires or those fueled by paper or flammable liquids. A newer, and perhaps safer, type is a photoelectric smoke detector.
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The optical system of the image dissector focuses an image onto a photocathode mounted inside a high vacuum. As light strikes the photocathode, electrons are emitted in proportion to the intensity of the light (see photoelectric effect). The entire electron image is deflected and a scanning aperture permits only those electrons emanating from a very small area of the photocathode to be captured by the detector at any given time. The output from the detector is an electric current whose magnitude is a measure of the brightness of the corresponding area of the image.
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The name BD was taken from a catalogue of the Bonner Durchmusterung (Bonn Survey) where observations are abbreviated as BD. Latter study expansions were carried out by the Cape Photographic Durchmusterung observatory in Córdoba, Argentina and further extensions by Henry Lee Giclas who designated the star as G 181-34 in the Giclas catalogues. From 1990 to 1993, HD 156668 was observed at least twice and was featured at the 6th annual catalog of the Tokyo Photoelectric Meridian Circle (PMC) where it is one of 6649 stars observed.
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Offshoot products from laboratory technology included resins, varnishes, foam, nonsmudge ink, adhesives, photoelectric readers and frequency standard instrumentation. Synthetic diamonds and emeralds were produced to test hardness in space age materials. While most of Melpar's efforts were technical, some involved the social sciences–creation of a stock index of S&P; 500 companies for Business Week, and operation of a Job Corps center. Melpar continued its work on military and space applications such as radar, communications, and electronic counter measure systems as well as airborne and ground intelligence systems.
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Previous color television demonstrations in the U.K. and U.S. had been via closed circuit. Mechanically scanned color television was also demonstrated by Bell Laboratories in June 1929 using three complete systems of photoelectric cells, amplifiers, glow-tubes and color filters, with a series of mirrors to superimpose the red, green and blue images into one full color image. The first practical hybrid system was again pioneered by John Logie Baird. In 1940 he publicly demonstrated a color television combining a traditional black-and- white display with a rotating colored disc.
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Max Planck, Albert Einstein, and Niels Bohr postulated the occurrence of energy in discrete quantities (quanta) in order to explain phenomena such as the spectrum of black-body radiation, the photoelectric effect, and the stability and spectra of atoms. These phenomena had eluded explanation by classical physics and even appeared to contradict it. Although elementary particles show predictable properties in many experiments, they become thoroughly unpredictable in others, such as attempts to identify individual particle trajectories through a simple physical apparatus. Classical physics draws a distinction between particles and waves.
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The first version of this catalog was published in 1989. The first catalog was created by digitizing photographic plates produced by the Palomar Schmidt Quick-V survey for the northern hemisphere and the UK Schmidt SERC-J survey for the southern hemisphere. This catalog contains objects in the magnitude range 7-16 and the classification was biased to prevent the use of a non-stellar object as a guide star. The photometry is based on a photoelectric sequence (9-15th mag) near the center of each Schmidt plate.
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MWC 480 has X-ray emissions typical of a pre-main-sequence Herbig Ae/Be star but with an order of magnitude more photoelectric absorption. It has a gas-dust envelope and is surrounded by a protoplanetary disc that is about 11% the mass of the Sun. The disc is inclined about 37° towards the line of sight, on a position angle of about 148°. Astronomers using the ALMA (Atacama Large Millimeter/submillimeter Array) have found that the protoplanetary disc surrounding MWC 480 contains large amounts of methyl cyanide (CH3CN), a complex carbon-based molecule.
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A solar cell or photovoltaic cell is a device that converts light energy into electrical energy. Fundamentally, the device needs to fulfill only two functions: photo-generation of charge carriers (electrons and holes) in a light-absorbing material, and separation of the charge carriers to a conductive contact that will transmit the electricity (simply put, carrying electrons off through a metal contact into an external circuit). This conversion is called the photoelectric effect, and the field of research related to solar cells is known as photovoltaics. Solar cells have many applications.
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They discovered that when an electron collided with a mercury atom it could lose only a specific quantity (4.9 electron volts) of its kinetic energy before flying away. A faster electron does not decelerate completely after a collision, but loses precisely the same amount of its kinetic energy. Slower electrons just bounce off mercury atoms without losing any significant speed or kinetic energy. These experimental results provided confirmation of Albert Einstein's photoelectric effect and Planck's relation (E = fh) linking energy (E) and frequency (f) arising from quantisation of energy with Planck's constant (h).
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Major research interests include: A. dynamic testing technology and intelligent instruments; B. Photoelectric Probing Theory and Technology; C. Special-type Sensing Theory and Technology; D. Modern Instrumentation and Testing Theory and Technology. Precision Instrumentations and Machinery Precision Instrumentations and Machinery is one of Shanxi provincial key disciplines. A research team composed of 8 doctorate supervisors, 12 professors, 10 associate professors or senior engineers engages itself in the discipline. In recent years, 11 awards for scientific and technological achievements at national, ministerial or provincial level have been granted to the discipline.
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C point is the rear-most measuring point and anchorage point for lifting and lining chords. Depending on type of chord system C point will be either wire anchor with a tensioning cylinder or a photoelectric light receiver. All three points are individual rail trolleys able to freely move up, down, left and right independent of the machine chassis and hence follow any minor fluctuation in rail position. When working, the machine uses pneumatic cylinders to lightly push these trolleys into the selected datum rail both vertically and horizontally.
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Planck introduced the concept of a hypothetical energy quantum to explain black-body radiation spectra in 1900. Translated in English translation Albert Einstein cemented the utility of quantum theory through explanation of the photoelectric effect in a 1905 paper. The fundamental concept that the energy E of any system that absorbs or emits electromagnetic radiation of frequency ν is an integer multiple of an energy quantum inspired Erwin Schrödinger to quantize the classical wave equation. Schrödinger arrived at what is now known as the Schrödinger equation published in 1926.
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Minox stand-alone selenium meter A selenium meter is a light-measuring instrument based on the photoelectric properties of selenium. The most common use of such light meters is measuring the exposure value for photography. The electric part of such a meter is an electromagnetic measuring instrument which is connected to the anode and cathode of a selenium photo cell that produces more or less electric power when exposed to more or less light. The optical part of such a meter is a window in front of the photo cell's light-sensitive side.
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The concentration of a sample can be calculated from the intensity of light before and after it passes through the sample by using the Beer–Lambert law. Photoelectric analyzers came to dominate in the 1960s. The color or wavelength of the filter chosen for the colorimeter is extremely important, as the wavelength of light that is transmitted by the colorimeter has to be the same as that absorbed by the substance being measured. For example, the filter on a colorimeter might be set to red if the liquid is blue.
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Gerald Kron (April 6, 1913 – April 9, 2012) was an American astronomer who was one of the pioneers of high-precision photometry with photoelectric instrumentation. He discovered the first starspot and made the first photometric observation of a stellar flare. A graduate of the University of Wisconsin-Madison, where he earned a Master of Science degree in mechanical engineering in 1934, Kron became interested in astronomy, which he studied under Joel Stebbins. Stebbins arranged for Kron to enter the University of California at Berkeley, where he received his doctorate in astronomy in 1938.
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Cousins singlemindedly devoted himself for the last 50 years of his life to photometry and its improvement by application of the photoelectric effect. In his early 1990s Cousins started to use a newly-available red- sensitive photomultiplier tube as part of a photometric system for information gathering on the energy distribution of red stars. This UBV photometric system was based on one devised by Gerald Kron and became known as the "Cousins system" (or sometimes the "Kron-Cousins system"). It allowed broadband, standardised fundamental measurements of stellar flux from near-ultraviolet to near-infrared wavelengths.
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" Nash, David. History of the University of Illinois Observatory and 12" Refractor , University of Illinois Astronomy Department, January 20, 1997 University of Illinois. Retrieved June 9, 2009 Wylie remained at the University of Illinois Observatory as an instructor until 1925 when he left for the University of Iowa where he remained for the rest of his career in the department of mathematics and astronomy. Trained in photoelectric photometry by Joel Stebbins, he shifted his research focus to meteors and meteorites because of the lack of equipment at Iowa City.
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UARPES - Ultra angle-resolved photoemission spectroscopy beamline allows for measurements of fundamental quantities, i.e. the energy and the momentum, describing a photoelectron state in the space outside the solid sample. If a spin selector is used additionally, a complete set of quantum numbers for the electron may be obtained. Then, within a so-called sudden approximation, the electron energy, momentum and spin measured over the sample surface may be related, to binding energy, quasimomentum, and spin, that the electron had in the solid before the photoelectric event took place.
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This implies that if two EM waves have the same intensity, but different frequencies, the one with the higher frequency "contains" fewer photons, since each photon is more energetic. When EM waves are absorbed by an object, the energy of the waves is converted to heat (or converted to electricity in case of a photoelectric material). This is a very familiar effect, since sunlight warms surfaces that it irradiates. Often this phenomenon is associated particularly with infrared radiation, but any kind of electromagnetic radiation will warm an object that absorbs it.
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Unique 3-D quantum confinement effects, combined with the unipolar (non-exciton based photoelectric behavior) nature of quantum dots could allow comparable performance to HgCdTe at significantly higher operating temperatures. Initial laboratory work has shown promising results in this regard and QDIPs may be one of the first significant nanotechnology products to emerge. In HgCdTe, detection occurs when an infrared photon of sufficient energy kicks an electron from the valence band to the conduction band. Such an electron is collected by a suitable external readout integrated circuits (ROIC) and transformed into an electric signal.
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Robert Andrews Millikan (March 22, 1868 – December 19, 1953) was an American experimental physicist honored with the Nobel Prize for Physics in 1923 for the measurement of the elementary electric charge and for his work on the photoelectric effect. Millikan graduated from Oberlin College in 1891 and obtained his doctorate at Columbia University in 1895. In 1896 he became an assistant at the University of Chicago, where he became a full professor in 1910. In 1909 Millikan began a series of experiments to determine the electric charge carried by a single electron.
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It also featured numerous drawings by Porter. The two later volumes contained chapters written by James Gilbert Baker, George Ellery Hale, George Willis Ritchey and others on topics ranging from lens grinding to monochromators to photoelectric photometry. Much of the information, including Porter's articles on the Springfield mount and Franklin Wright's and Henry E. Paul's articles on the design and construction of Schmidt cameras, appeared for the first and only time in these books. The ATM books are widely credited with having initiated the amateur telescope making movement in the United States.
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Photoelectric photometry using the CCD is now frequently used to make observations through a telescope. These sensitive instruments can record the image nearly down to the level of individual photons, and can be designed to view in parts of the spectrum that are invisible to the eye. The ability to record the arrival of small numbers of photons over a period of time can allow a degree of computer correction for atmospheric effects, sharpening up the image. Multiple digital images can also be combined to further enhance the image.
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In 1953, GE purchased the old, no longer used, Waynesboro airport, consisting of 75 acres of land located just west of the Norfolk &Western; Railroad and north of what was to become Hopeman Parkway—43 of them improved with the plant, parking lots, and finished grounds. Construction of the new plant began, and by the summer of 1954 had reached a point where production of photoelectric devices was begun with the relocation of supervisory personnel from Schenectady, and the hiring of approximately 10 women from the local area.
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On June 9, 1922, Tykociner publicly demonstrated for the first time a motion picture with a soundtrack optically recorded directly onto the film. When Tykociner demonstrated the first sound-on-film motion picture recordings the projector had a photoelectric cell made by his Illinois colleague Jakob Kunz at its heart. In the first sounds ever publicly heard from a composite image-and-audio film, Helena Tykociner, the inventor's wife, spoke the words, "I will ring," and then rang a bell. Next, Ellery Paine, head of the university's Department of Electrical Engineering, recited the Gettysburg Address.
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Individual photons can be detected by several methods. The classic photomultiplier tube exploits the photoelectric effect: a photon of sufficient energy strikes a metal plate and knocks free an electron, initiating an ever-amplifying avalanche of electrons. Semiconductor charge-coupled device chips use a similar effect: an incident photon generates a charge on a microscopic capacitor that can be detected. Other detectors such as Geiger counters use the ability of photons to ionize gas molecules contained in the device, causing a detectable change of conductivity of the gas.
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The current drawn by an ionization smoke detector is low enough for a small battery used as sole or backup power supply to be able to provide power for months or years without the need for external wiring. Ionization smoke detectors are usually cheaper to manufacture than optical detectors. They may be more prone to false alarms triggered by non-hazardous events than photoelectric detectors,Residential Smoke Alarm Performance, Thomas Cleary, Building and Fire Research Laboratory, National Institute of Standards and Technology, UL Smoke and Fire Dynamics Seminar. November, 2007.
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The effect has found use in electronic devices specialized for light detection and precisely timed electron emission. In classical electromagnetic theory, the photoelectric effect would be attributed to the transfer of energy from the continuous light waves to an electron. An alteration in the intensity of light would change the kinetic energy of the emitted electrons, and sufficiently dim light would result in the emission delayed by the time it would take the electrons to accumulate enough energy to leave the material. The experimental results, however, disagree with both predictions.
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In extreme cases, emissions are induced with photons approaching zero energy, like in systems with negative electron affinity and the emission from excited states, or a few hundred keV photons for core electrons in elements with a high atomic number. Study of the photoelectric effect led to important steps in understanding the quantum nature of light and electrons and influenced the formation of the concept of wave–particle duality. Other phenomena where light affects the movement of electric charges include the photoconductive effect, the photovoltaic effect, and the photoelectrochemical effect.
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Even though photoemission can occur from any material, it is most readily observed from metals and other conductors. This is because the process produces a charge imbalance which, if not neutralized by current flow, results in the increasing potential barrier until the emission completely ceases. The energy barrier to photoemission is usually increased by nonconductive oxide layers on metal surfaces, so most practical experiments and devices based on the photoelectric effect use clean metal surfaces in evacuated tubes. Vacuum also helps observing the electrons since it prevents gases from impeding their flow between the electrodes.
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With regard to the Hertz effect, the researchers from the start showed the complexity of the phenomenon of photoelectric fatigue—the progressive diminution of the effect observed upon fresh metallic surfaces. According to Hallwachs, ozone played an important part in the phenomenon, and the emission was influenced by oxidation, humidity, and the degree of polishing of the surface. It was at the time unclear whether fatigue is absent in a vacuum. In the period from 1888 until 1891, a detailed analysis of the photoeffect was performed by Aleksandr Stoletov with results reported in six publications.
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Stoletov invented a new experimental setup which was more suitable for a quantitative analysis of the photoeffect. He discovered a direct proportionality between the intensity of light and the induced photoelectric current (the first law of photoeffect or Stoletov's law). He measured the dependence of the intensity of the photo electric current on the gas pressure, where he found the existence of an optimal gas pressure corresponding to a maximum photocurrent; this property was used for the creation of solar cells. Many substances besides metals discharge negative electricity under the action of ultraviolet light.
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For neutrons, all reactions given in a particular cross-section evaluation (such as ENDF/B-VI) are accounted for. Thermal neutrons are described by both the free gas and S(α,β) models. For photons, the code accounts for incoherent and coherent scattering, the possibility of fluorescent emission after photoelectric absorption, absorption in pair production with local emission of annihilation radiation, and bremsstrahlung. A continuous-slowing-down model is used for electron transport that includes positrons, k x-rays, and bremsstrahlung but does not include external or self-induced fields.
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In 1953, Gavrilă was accepted for doctoral studies in theoretical physics by Professor Șerban Țițeica in the School of Physics at the University of Bucharest. He completed successfully his doctoral studies with a Ph.D. thesis entitled The Relativistic Theory of the Photoelectric Effect, building on work of Albert Einstein and Alexandru Proca.Alexandru Proca. "On the relativistic theory of Dirac's electron" Ph.D. thesis defended by Alexandru Proca under Nobel laureate Louis de Broglie at Sorbonne University He published in 1959 the main results of his Ph.D. thesis in a peer-reviewed paper in Physical Review.
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Beams completed his undergraduate B.A. in physics at Fairmount College in 1921 and his master's degree the next year at the University of Wisconsin. He spent most of his academic career at the University of Virginia, where he received his Ph.D. in physics in 1925. He spent the next three years in a physics fellowship at Yale University, where he performed research on the photoelectric effect with Ernest Lawrence. Beams was appointed a professor of physics at the University of Virginia in 1929 and was chair of the department from 1948 to 1962.
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He attempted to study industrial design but instead entered the photoelectric arts department at the Ontario College of Art. In many of Fung's works relating to his family, such as Sea in the Blood (2000), he explores how lesbians and gay men experience being exiled by kinship. The coming-out process provokes fraught relationships between members of LGBT and their families and the AIDS pandemic contributes to an environment of exclusion and disappointment. Fung's works focus widely on queers of colour, drawing predominantly from personal experiences as an Asian homosexual.
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Active solar technologies encompass solar thermal energy, using solar collectors for heating, and solar power, converting sunlight into electricity either directly using photovoltaics (PV), or indirectly using concentrated solar power (CSP). A photovoltaic system converts light into electrical direct current (DC) by taking advantage of the photoelectric effect. Solar PV has turned into a multi-billion, fast-growing industry, continues to improve its cost- effectiveness, and has the most potential of any renewable technologies together with CSP.NREL.gov U.S. Renewable Energy Technical Potentials: A GIS- Based Analysis, July 2013 thinkprogress.
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A few musical instruments have been manufactured using optical sound for playback. Keyboard overview of a model 35002 Optigan In 1971 toy manufacturer Mattel released the Optigan (short for "optical organ), an organ-like synthesizer whose sound library was stored on interchangeable 12" clear acetate "program discs". Each program disc was encoded with 57 concentric optical tracks that spun on a turntable inside the machine. The Optigan then translated the analog waveforms on each disc to an audio signal via an exciter lamp shone through the disc and onto a photoelectric cell.
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X-ray tubes used for continuous-duty operation in fluoroscopy and CT imaging equipment may use a focused cathode and a rotating anode to dissipate the large amounts of heat thereby generated. These are housed in an oil-filled aluminum housing to provide cooling. The photomultiplier tube is an extremely sensitive detector of light, which uses the photoelectric effect and secondary emission, rather than thermionic emission, to generate and amplify electrical signals. Nuclear medicine imaging equipment and liquid scintillation counters use photomultiplier tube arrays to detect low-intensity scintillation due to ionizing radiation.
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The black-body problem was revisited in 1905, when Rayleigh and Jeans (on the one hand) and Einstein (on the other hand) independently proved that classical electromagnetism could never account for the observed spectrum. These proofs are commonly known as the "ultraviolet catastrophe", a name coined by Paul Ehrenfest in 1911. They contributed greatly (along with Einstein's work on the photoelectric effect) in convincing physicists that Planck's postulate of quantized energy levels was more than a mere mathematical formalism. The first Solvay Conference in 1911 was devoted to "the theory of radiation and quanta".
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When a gamma photon leaves the patient (who has been injected with a radioactive pharmaceutical), it knocks an electron loose from an iodine atom in the crystal, and a faint flash of light is produced when the dislocated electron again finds a minimal energy state. The initial phenomenon of the excited electron is similar to the photoelectric effect and (particularly with gamma rays) the Compton effect. After the flash of light is produced, it is detected. Photomultiplier tubes (PMTs) behind the crystal detect the fluorescent flashes (events) and a computer sums the counts.
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The probability of a photoelectric absorption per unit mass is approximately proportional to Z3/E3, where Z is the atomic number and E is the energy of the incident photon. This rule is not valid close to inner shell electron binding energies where there are abrupt changes in interaction probability, so called absorption edges. However, the general trend of high absorption coefficients and thus short penetration depths for low photon energies and high atomic numbers is very strong. For soft tissue, photoabsorption dominates up to about 26 keV photon energy where Compton scattering takes over.
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Repetition of the experiment under different conditions was carried out by Leistner, a Wiener's student, to better characterize the radiation. Leistner modified a Mach–Zehnder interferometer so as to insert the film between the mirrors. Another repetition was the thesis of Ernst Schult, commissioned by Nernst and Max von Laue for comparing light intensity with the energy as measured with a micropyrometer, along the verification of the energy quantization hypothesis with respect to the simple wave theory. A further notable repetition, aimed at evaluating the dependence of a cesium film's photoelectric emission upon illumination conditions.
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In the 1970s Mr G.Crookbank the tracks chief electrician had invented photoelectric timing gear that would revolutionise the sport. Hand timing would become a thing of the past after Crookbank came up with the idea that a greyhound’s race time could be recorded electronically. The invention known as 'Automatic Ray Timing' would remain as the timing method until the advent of modern computer timing. The Hackney sales became a major feature of business throughout the year, these sales became a prominent way for buying and selling greyhounds in London.
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A core electron can be removed from its core-level upon absorption of electromagnetic radiation. This will either excite the electron to an empty valence shell or cause it to be emitted as a photoelectron due to the photoelectric effect. The resulting atom will have an empty space in the core electron shell, often referred to as a core-hole. It is in a metastable state and will decay within 10−15 s, releasing the excess energy via X-ray fluorescence (as a characteristic X-ray) or by the Auger effect.
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The approximate nature of Maxwell's equations becomes more and more apparent when going into the extremely strong field regime (see Euler–Heisenberg Lagrangian) or to extremely small distances. Finally, Maxwell's equations cannot explain any phenomenon involving individual photons interacting with quantum matter, such as the photoelectric effect, Planck's law, the Duane–Hunt law, and single-photon light detectors. However, many such phenomena may be approximated using a halfway theory of quantum matter coupled to a classical electromagnetic field, either as external field or with the expected value of the charge current and density on the right hand side of Maxwell's equations.
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Quintron playing Drum Buddy The Drum Buddy, invented by New Orleans Ninth Ward one-man band Quintron, is a light-activated oscillating drum machine which operates on the principles of an optical sound theremin. An electronic instrument developed in the Spellcaster Lodge QElectronics laboratory, only 44 units hand-assembled by Quintron exist. Its four voices – Space, Snare, Bass and Kick, are triggered by activating a photoelectric cell either intermittently or with an on/off DIP switch in combination with exposure to light. The Drum Buddy is outfitted with a light fixture on a periscopic pipe fixed to its base.
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After the war Johnson began graduate studies in astronomy at University of California, Berkeley where he completed his thesis under Harold Weaver in 1948. In the following years working at Lowell Observatory, University of Wisconsin–Madison, Yerkes Observatory (where he met William Wilson Morgan), McDonald Observatory, University of Texas–Austin, the Lunar and Planetary Laboratory in Tucson, Arizona, and the National Autonomous University of Mexico he applied his instrumental and electronic talents to developing and calibrating astronomical photoelectric detectors. He died of a heart attack in Mexico City in 1980. He and his wife, Mary Elizabeth Jones, had two children.
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A photoelectric sensor protruded from the center of the ring. The sensor was designed with two photocells which would be triggered by the light of the Moon when the probe was within about 30,000 km of the Moon. Under original plans, the probe would have carried a camera capable of taking a single photograph of the Moon, but after the discovery of the Van Allen Belts by Explorer 1, the camera was replaced with a Geiger counter for radiation measuring. At the center of the cone were a voltage supply tube and two Geiger-Müller tubes.
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In 1981, Nouvel, together with Architecture-Studio, won the design competition for the Institut du Monde Arabe (Arab World Institute) building in Paris, whose construction was completed in 1987 and brought Nouvel international fame. Mechanical lenses reminiscent of Arabic latticework in its south wall open and shut automatically, controlling interior lighting as the lenses' photoelectric cells respond to exterior light levels. Nouvel had three different partners between 1972 and 1984: Gilbert Lezenes, Jean-François Guyot, and Pierre Soria. In 1985, with his junior architects Emmanuel Blamont, Jean-Marc Ibos and Mirto Vitart, he founded Jean Nouvel et Associés.
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Johanna (minor planet designation: 127 Johanna) is a large, dark main-belt asteroid that was discovered by French astronomers Paul Henry and Prosper Henry on 5 November 1872, and is believed to be named after Joan of Arc. It is classified as a CX-type asteroid, indicating the spectrum shows properties of both a carbonaceous C-type asteroid and a metallic X-type asteroid. A photoelectric study was performed of this minor planet in 1991 at the Konkoly Observatory in Hungary. The resulting light curve showed a synodic rotation period of 6.94 ± 0.29 hours with a brightness variation of 0.2 in magnitude.
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A photo-electric cell is connected to a circuit that measures how much electricity the cell produces and according to the setting of minimum and maximum lux level, the circuit decides and gives the output.PHOTOSWITCH Photoelectric Sensors Photoswitches have recently also been used in the generation of three-dimensional animations and images. The display utilizes a medium composed of a class of photoswitches (known as spirhodamines) and digital light processing (DLP) technology to generate structured light in three dimensions. UV light and green light patterns are aimed at the dye solution, which initiates photoactivation and thus creates the 'on' voxel.
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At the same time, the Agency took responsibility for issuing flood warnings to the public, a role previously held by the police. In 2010 a new national headquarters for the agency was opened at Horizon House in Deanery Road, Bristol. The building, which was designed by Alec French Architects, won the Building Research Establishment Environmental Assessment (BREEAM) Award for its environmentally friendly construction and operation which includes the use of sustainable materials, natural ventilation and cooling, photoelectric panels and rainwater harvesting. On 24 April 2013, Horizon House suffered a fire leading to its closure for several weeks.
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The Factory Automation Division is a manufacturer of industrial sensors designed to address specific market needs on a global basis. It makes a range of inductive, capacitive, photoelectric, and ultrasonic sensors as well as identification systems, barcode and camera systems, rotary encoders, position measurement systems, cord-sets, and other accessories. - The Process Automation Division claims to be the market leader in intrinsically safe explosion protection components and protection of hazardous area applications. In 2019, Pepperl+Fuchs Control partnered with Callisto Integration, a leading Systems Integrator in Manufacturing Industry to enable companies seamlessly implement solutions that provide Transparency and Control of their manufacturing operations.
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Corson served as the first Artist-in- Residence for the City of Seattle's "% for Arts program" in 2001. His work is often interactive and incorporates elements such as photoelectric switches which the spectator can trigger and cause the artwork to respond. Typical is Emerald Aura a temporary laser sculpture in Memphis Tennessee that used Infrared cameras and surveillance software to track pedestrians and project the processed computer generated images back onto the people in real time. This installation is typical of Corson’s work in the way that it combine artistic expression with an implied statement about our culture.
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In the 1960s, the Coast Guard automated the Dofflemyer Point Lighthouse, using photoelectric cells to turn the light on and off. However, a contract keeper was still required to maintain the light and tower, and to activate the fog signal when needed. The lighthouse was fully automated in 1987 and a radio-beacon, which transmitted a radio signal used in locating a mariner's position, was installed. On May 1, 1995, the Dofflemyer Point Lighthouse was officially designated by the Washington State Advisory Council on Historic Preservation as an historic place and listed on the Washington Heritage Register.
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In X-ray absorption spectroscopy, the K-edge is a sudden increase in x-ray absorption occurring when the energy of the X-rays is just above the binding energy of the innermost electron shell of the atoms interacting with the photons. The term is based on X-ray notation, where the innermost electron shell is known as the K-shell. Physically, this sudden increase in attenuation is caused by the photoelectric absorption of the photons. For this interaction to occur, the photons must have more energy than the binding energy of the K-shell electrons (K-edge).
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John Conrad Jaeger, FRS (30 July 1907 – 15 May 1979) was an Australian mathematical physicist. He was born in Sydney, Australia to Carl Jaeger, a cigar manufacturer of German origin. In 1924 Jaeger entered Sydney University at the age of 16 and studied engineering, mathematics and physics, gaining a B.Sc. in 1928. He then spent a further two years studying mathematics at Cambridge University, completing Part II of the Mathematical Tripos, after which he stayed on to carry out research in theoretical physics, mainly on the photoelectric effect, the propagation of electromagnetic waves in ionized media and on circuit theory.
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Entrance of Mitaka Campus 65cm refractor dome, now Observatory History Museum VERA Ishigakijima Station Subaru Telescope ;Mitaka Campus (Mitaka, Tokyo. ) :The Headquarters, Astronomy Data Center, Advanced Technology Center, Public Relations Center :Solar Flare Telescope, Sunspot Telescope, TAMA 300 gravitational wave detector :Tokyo Photoelectric Meridian Circle :Historical instruments: Solar Tower Telescope, 65cm refractor dome, 20cm refractor dome ;Nobeyama Radio Observatory & Nobeyama Solar Radio Observatory (Minamimaki, Nagano, ) :45m Millimeter Radio Telescope, Nobeyama Millimeter Array, Nobeyama Radio Heliograph ;Mizusawa VERA Observatory (Ōshū, Iwate. ) :20m radio telescope, 10m VLBI radio telescope :Historical building: Dr. Kimura Museum ;Okayama Astrophysical Observatory (Mt. Chikurinji in Asakuchi, Okayama.
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Photographic magnitude (' or ' ) is a measure of the relative brightness of a star or other astronomical object as imaged on a photographic film emulsion with a camera attached to a telescope. An object's apparent photographic magnitude depends on its intrinsic luminosity, its distance and any extinction of light by interstellar matter existing along the line of sight to the observer. Photographic observations have now been superseded by electronic photometry such as CCD charge-couple device cameras that convert the incoming light into an electric current by the photoelectric effect. Determination of magnitude is made using a photometer.
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The modern photon concept originated during the first two decades of the 20th century with the work of Albert Einstein, who built upon the research of Max Planck. While trying to explain how matter and electromagnetic radiation could be in thermal equilibrium with one another, Planck proposed that the energy stored within a material object should be regarded as composed of an integer number of discrete, equal-sized parts. To explain the photoelectric effect, Einstein introduced the idea that light itself is made of discrete units of energy. In 1926, Gilbert N. Lewis popularized the term photon for these energy units.
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Quantum mechanics arose gradually, from theories to explain observations which could not be reconciled with classical physics, such as Max Planck's solution in 1900 to the black-body radiation problem, and the correspondence between energy and frequency in Albert Einstein's 1905 paper which explained the photoelectric effect. Early quantum theory was profoundly re-conceived in the mid-1920s by Niels Bohr, Erwin Schrödinger, Werner Heisenberg, Max Born and others. The original interpretation of quantum mechanics is the Copenhagen interpretation, developed by Niels Bohr and Werner Heisenberg in Copenhagen during the 1920s. The modern theory is formulated in various specially developed mathematical formalisms.
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In this scenario, the electron is treated as free or loosely bound. Experimental verification of momentum conservation in individual Compton scattering processes by Bothe and Geiger as well as by Compton and Simon has been important in disproving the BKS theory. Compton scattering is one of three competing processes when photons interact with matter. At energies of a few eV to a few keV, corresponding to visible light through soft X-rays, a photon can be completely absorbed and its energy can eject an electron from its host atom, a process known as the photoelectric effect.
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In the 1890s, Planck was able to derive the blackbody spectrum which was later used to avoid the classical ultraviolet catastrophe by making the unorthodox assumption that, in the interaction of electromagnetic radiation with matter, energy could only be exchanged in discrete units which he called quanta. Planck postulated a direct proportionality between the frequency of radiation and the quantum of energy at that frequency. The proportionality constant, , is now called Planck's constant in his honor. In 1905, Einstein explained certain features of the photoelectric effect by assuming that Planck's energy quanta were actual particles, which were later dubbed photons.
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Also as an example, the use of silicon nanowires in nanoporous materials to create scaffolds for synthetic tissues allows for monitoring of electrical activity and electrical stimulation of cells as a result of the photoelectric properties of the silicon. The orientation of biomolecules on the interface can also be controlled through the modulation of parameters like pH, temperature and electrical field. For example, DNA grafted onto gold electrodes can be made to come closer to the electrode surface on application of positive electrode potential and as explained by Rant et al., this can be used to create smart interfaces for biomolecular detection.
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A photoelectric device can be either intrinsic or extrinsic. An intrinsic semiconductor has its own charge carriers and is not an efficient semiconductor, for example, silicon. In intrinsic devices, the only available electrons are in the valence band, and hence the photon must have enough energy to excite the electron across the entire bandgap. Extrinsic devices have impurities, also called dopants, added whose ground state energy is closer to the conduction band; since the electrons do not have as far to jump, lower energy photons (that is, longer wavelengths and lower frequencies) are sufficient to trigger the device.
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Angle-resolved photoemission spectroscopy (ARPES) is a powerful technique used in condensed matter physics to probe the structure of the electrons in a material, usually a crystalline solid. The technique is best suited for use in one- or two-dimensional materials. It is based on the photoelectric effect, in which an incoming photon of sufficient frequency dislodges an electron from the surface of a material. By directly measuring the kinetic energy and momentum distributions of the emitted photoelectrons, the technique can be used to map the electronic band structure, provide elemental information, and map Fermi surfaces.
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TLS accelerator computer card uses a hardware random number generator to generate cryptographic keys to encrypt data sent over computer networks. In computing, a hardware random number generator (HRNG) or true random number generator (TRNG) is a device that generates random numbers from a physical process, rather than by means of an algorithm. Such devices are often based on microscopic phenomena that generate low-level, statistically random "noise" signals, such as thermal noise, the photoelectric effect, involving a beam splitter, and other quantum phenomena. These stochastic processes are, in theory, completely unpredictable, and the theory's assertions of unpredictability are subject to experimental test.
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Mechanically scanned color television was also demonstrated by Bell Laboratories in June 1929 using three complete systems of photoelectric cells, amplifiers, glow-tubes, and color filters, with a series of mirrors to superimpose the red, green, and blue images into one full color image. The first practical hybrid system was again pioneered by John Logie Baird. In 1940 he publicly demonstrated a color television combining a traditional black-and- white display with a rotating colored disk. This device was very "deep", but was later improved with a mirror folding the light path into an entirely practical device resembling a large conventional console.
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The energy transferred by a wave in a given time is called its intensity. The light from a theatre spotlight is more intense than the light from a domestic lightbulb; that is to say that the spotlight gives out more energy per unit time and per unit space (and hence consumes more electricity) than the ordinary bulb, even though the color of the light might be very similar. Other waves, such as sound or the waves crashing against a seafront, also have their intensity. However, the energy account of the photoelectric effect didn't seem to agree with the wave description of light.
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Further, it is currently difficult to produce such crystals without defects and impurities, which cause detector polarisation and incomplete charge collection. Silicon detectors, on the other hand, are more easily manufactured and less prone to pileup due to high charge carrier mobility. They do not suffer from K-escape X-rays but have a lower photoelectric-to- Compton ratio at X-ray energies used in CT imaging, which degrades the collected energy spectrum. Further, silicon attenuates X-rays less strongly and therefore silicon detectors have to be several centimetres thick to be useful in a CT system.
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His doctoral thesis was entitled A Photoelectric Study of Some RV Tauri and Yellow Semiregular Variables and was written under the supervision of Cecilia Payne-Gaposchkin. While on a cross-country return trip from Tucson, where he had just completed his research for his PhD thesis, he was arrested by plainclothes police officers at a San Francisco bus terminal after a stranger had approached and groped him. He was promised that his criminal record would be expunged after serving three years' probation, relieving him from worrying about his employment prospects and any attempt at fighting the charges.Carter, David.
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In 1939 he became head of the Laboratory of Optical Works A&C; Steinheil & Söhne, Munich. In 1945 he quit the job and ventured into self-employment. Because he was politically unencumbered, Erwin Sick received his license to "Practice his profession as an engineer" on 26 September 1946 by the American military government. That was the birth of the company that later became known as Sick AG. In June 1951 "German Inventors and Innovations Fair" was held in Munich where Sick presented his first finished wooden model of Photoelectric sensor and received a certificate "for creative performance".
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Elektro the Moto-Man and his Little Dog Sparko Elektro is the nickname of a robot built by the Westinghouse Electric Corporation in its Mansfield, Ohio facility between 1937 and 1938. Seven feet tall (2.1 m), weighing 265 pounds (120.2 kg), humanoid in appearance, he could walk by voice command, speak about 700 words (using a 78-rpm record player), smoke cigarettes, blow up balloons, and move his head and arms. Elektro's body consisted of a steel gear, cam and motor skeleton covered by an aluminum skin. His photoelectric "eyes" could distinguish red and green light.
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The fixture's bulb can be controlled by means of a dimmer switch. The bulb hangs above a rotating platen upon which a number 10 can (the large size common to coffee, canned vegetables and some sauces) prepared with holes and non-reflective paint is placed. As the can rotates, its holes pass the Drum Buddy's photoelectric cells, firing drum-like tones and theremin or Moog synthesizer-like chirps or buzzes. Accomplished purveyors of the Drum Buddy can operate the instrument freestyle by "scratching" the can back and forth against the resistance of the platen's motor or by performing short solos on the bass channel's 12-point chromatic scale.
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In 1917 Theremin wrote that Ioffe talked of electrons, the photoelectric effect and magnetic fields as parts of an objective reality that surrounds us every day, unlike others that talked more of somewhat abstract formulae and symbols. Theremin wrote that he found this explanation revelatory and that it fit a scientific – not abstract – view of the world, different scales of magnitude, and matter. From then on Theremin endeavoured to study the microcosm, in the same way he had studied the macrocosm with his hand-built telescope. Later, Kyrill introduced Theremin to Ioffe as a young experimenter and physicist, and future student of the university.
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The photoelectric screen in the proposed transmitting device was a mosaic of isolated rubidium cubes. His concept for a fully electronic television system was later popularized by Hugo Gernsback as the "Campbell-Swinton Electronic Scanning System" in the August 1915 issue of the popular magazine Electrical Experimenter. In a letter to Nature published in October 1926, Campbell- Swinton also announced the results of some "not very successful experiments" he had conducted with G. M. Minchin and J. C. M. Stanton. They had attempted to generate an electrical signal by projecting an image onto a selenium-coated metal plate that was simultaneously scanned by a cathode ray beam.
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The first small- scale applications for caesium were as a "getter" in vacuum tubes and in photoelectric cells. In 1967, acting on Einstein's proof that the speed of light is the most constant dimension in the universe, the International System of Units used two specific wave counts from an emission spectrum of caesium-133 to co-define the second and the metre. Since then, caesium has been widely used in highly accurate atomic clocks. Since the 1990s, the largest application of the element has been as caesium formate for drilling fluids, but it has a range of applications in the production of electricity, in electronics, and in chemistry.
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Very few applications existed for caesium until the 1920s, when it came into use in radio vacuum tubes, where it had two functions; as a getter, it removed excess oxygen after manufacture, and as a coating on the heated cathode, it increased the electrical conductivity. Caesium was not recognized as a high-performance industrial metal until the 1950s. Applications for nonradioactive caesium included photoelectric cells, photomultiplier tubes, optical components of infrared spectrophotometers, catalysts for several organic reactions, crystals for scintillation counters, and in magnetohydrodynamic power generators. Caesium also was, and still is, used as a source of positive ions in secondary ion mass spectrometry (SIMS).
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Sagan recalls that one of his most defining moments was when his parents took him to the 1939 New York World's Fair when he was four years old. The exhibits became a turning point in his life. He later recalled the moving map of the America of Tomorrow exhibit: "It showed beautiful highways and cloverleaves and little General Motors cars all carrying people to skyscrapers, buildings with lovely spires, flying buttresses—and it looked great!" At other exhibits, he remembered how a flashlight that shone on a photoelectric cell created a crackling sound, and how the sound from a tuning fork became a wave on an oscilloscope.
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Cathodoluminescence is an optical and electromagnetic phenomenon in which electrons impacting on a luminescent material such as a phosphor, cause the emission of photons which may have wavelengths in the visible spectrum. A familiar example is the generation of light by an electron beam scanning the phosphor-coated inner surface of the screen of a television that uses a cathode ray tube. Cathodoluminescence is the inverse of the photoelectric effect, in which electron emission is induced by irradiation with photons. Sketch of a cathodoluminescence system: The electron beam passes through a small aperture in the parabolic mirror which collects the light and reflects it into the spectrometer.
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In 1900 Max Planck, attempting to explain black-body radiation, suggested that although light was a wave, these waves could gain or lose energy only in finite amounts related to their frequency. Planck called these "lumps" of light energy "quanta" (from a Latin word for "how much"). In 1905, Albert Einstein used the idea of light quanta to explain the photoelectric effect, and suggested that these light quanta had a "real" existence. In 1923 Arthur Holly Compton showed that the wavelength shift seen when low intensity X-rays scattered from electrons (so called Compton scattering) could be explained by a particle-theory of X-rays, but not a wave theory.
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The presence of a mass causes a curvature of space- time in the vicinity of the mass, and this curvature dictates the space-time path that all freely-moving objects must follow. It was also predicted from this theory that light should be subject to gravity - all of which was verified experimentally. This aspect of relativity explained the phenomena of light bending around the sun, predicted black holes as well as properties of the Cosmic microwave background radiation — a discovery rendering fundamental anomalies in the classic Steady-State hypothesis. For his work on relativity, the photoelectric effect and blackbody radiation, Einstein received the Nobel Prize in 1921.
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Basic components of a monochromatic XPS system. X-ray photoelectron spectroscopy (XPS) is a surface-sensitive quantitative spectroscopic technique based on the photoelectric effect that can identify the elements that exist within a material (elemental composition) or are covering its surface, as well as their chemical state, and the overall electronic structure and density of the electronic states in the material. XPS is a powerful measurement technique because it not only shows what elements are present, but also what other elements they are bonded to. The technique can be used in line profiling of the elemental composition across the surface, or in depth profiling when paired with ion-beam etching.
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His postgraduate studies at UMIST related to the study of astronomical spectra using a photoelectric photometer. His work parallelled that of Hiltner (1914–1991) and his group in U.S.A.; although at the time, neither knew of the other's work, and their methods were different. This research (which was long before the days of space exploration) led to laboratory measurement of luminescence from meteorite samples, which could be compared with lunar luminescence in an attempt to determine the composition of the lunar surface. His expertise was recognised by both the American and the Soviet space agencies, both of whom allocated to him lunar samples for study.
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A scintillation detector or scintillation counter is obtained when a scintillator is coupled to an electronic light sensor such as a photomultiplier tube (PMT), photodiode, or silicon photomultiplier. PMTs absorb the light emitted by the scintillator and re-emit it in the form of electrons via the photoelectric effect. The subsequent multiplication of those electrons (sometimes called photo-electrons) results in an electrical pulse which can then be analyzed and yield meaningful information about the particle that originally struck the scintillator. Vacuum photodiodes are similar but do not amplify the signal while silicon photodiodes, on the other hand, detect incoming photons by the excitation of charge carriers directly in the silicon.
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Three months were required to produce a sufficient exposure of the photographic plate. The paper does not mention quanta of light (photons) and does not reference Einstein's 1905 paper on the photoelectric effect, but today the result can be interpreted by saying that less than one photon on average was present at a time. Once it became widely accepted ca. 1927 that the electromagnetic field was quantized, Taylor's experiment began to be presented in pedagogical treatments as evidence that interference effects with light cannot be interpreted in terms of one photon interfering with another photon—that, in fact, a single photon must travel through both slits of a double-slit apparatus.
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However, they noted significant levels of uncertainty regarding dose estimates for internal emitters, especially regarding less common radionuclides such as 239Pu and 241Am, and even more common ones such as 90Sr. Two of the twelve members disagreed with the overall findings, notably Christopher Busby who advocates controversial physico-biological mechanisms such as Second Event Theory and Photoelectric Effect Theory, by which he believes the danger of ingested particles could be greatly enhanced. Another study largely corroborates the CERRIE findings, though emphasising the paucity of useful data, substantial uncertainties over accuracy, and the existence of evidence for at least some modest "enhanced cell transformation for hot-particle exposures".
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The patient-operated selector mechanism (POSM or POSSUM), was developed in the early 1960s SGDs have their roots in early electronic communication aids. The first such aid was a sip-and-puff typewriter controller named the patient-operated selector mechanism (POSSUM) prototyped by Reg Maling in the United Kingdom in 1960.Vanderheide (2002)Zangari (1994) POSSUM scanned through a set of symbols on an illuminated display. Researchers at Delft University in the Netherlands created the lightspot operated typewriter (LOT) in 1970, which made use of small movements of the head to point a small spot of light at a matrix of characters, each equipped with a photoelectric cell.
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Suspicious of the general adulation of Einstein, Lenard became a prominent skeptic of relativity and of Einstein's theories generally; he did not, however, dispute Einstein's explanation of the photoelectric effect. Lenard grew extremely resentful of the credit accorded to Wilhelm Röntgen, who received the first Nobel Prize in physics in 1901, for the discovery of the X-ray, despite the fact that Wilhelm Röntgen was German and a non-Jew. Lenard wrote that he, not Roentgen, was the “mother of the X-rays,” since he had invented the apparatus used to produce them. Lenard likened Röntgen’s role to that of a “midwife” who merely assists with the birth.
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This technology was also used in a mass digitization project from the Bavarian State Library where 8,900 books from the 16th century became digitized using three of these v-shape scanners within 18 months. ScanRobot. Automated scanner with 60° opening angle Indus International, Inc, based in West Salem, WI, produces scanners which were bought by some US entities for services like interlibrary loan. Most high-end commercial robotic scanners use traditional air and suction technology while some others use alternative approaches like bionic fingers for turning pages. Some scanners take advantage of ultrasonic sensors or photoelectric sensors to detect dual pages and prevent skipping of pages.
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Woodward's scientific publications included "A study of four W Ursae Majoris stars" (Harvard College Observatory Circular 1942), "A photometric analysis of the supergiant close binary V453 Scorpii" (Publications of the Astronomical Society of the Pacific 1975, with Robert H. Koch), "AK Herculis — An atypical W UMa-type system" (Astrophysics and Space Science 1977, with R. E. Wilson), "U, B, V light curves of CO Lacertae" (Astrophysics and Space Science 1983, with R. E. Wilson), "Old and new observations of V523 Saggitarii" (Astronomical Journal 1989, with Robert H. Koch), and "Analyses of photoelectric light curves of YY Sagittarii" (Astronomical Journal 1992, with Robert H. Koch).
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He began by measuring the course of charged water droplets in an electric field. The results suggested that the charge on the droplets is a multiple of the elementary electric charge, but the experiment was not accurate enough to be convincing. He obtained more precise results in 1910 with his famous oil-drop experiment in which he replaced water (which tended to evaporate too quickly) with oil. In 1914 Millikan took up with similar skill the experimental verification of the equation introduced by Albert Einstein in 1905 to describe the photoelectric effect. He used this same research to obtain an accurate value of Planck’s constant.
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In the summer of 1906, Pohl completed his doctorate (Dr. Phil.) and took an assistantship in Berlin, working as instructor in the physics teaching labs under Heinrich Rubens, the Institute's director. He published joint articles with James Franck on ionic mobility in gases and on the propagation velocity of X-rays. From 1909 onward, he carried out research on the normal and the selective photoelectric effect in metals, and from 1910 he worked with Peter Pringsheim,"Die lichtelektrischen Erscheinungen", R. Pohl und P. Pringsheim, Verlag Friedr. Vieweg & Sohn, Braunschweig 1914 on, among other things, the technically important problem of the fabrication of metal mirrors.
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The old quantum theory is a collection of results from the years 1900–1925 which predate modern quantum mechanics. The theory was never complete or self- consistent, but was rather a set of heuristic corrections to classical mechanics. The theory is now understood as a semi-classical approximation to modern quantum mechanics. Notable results from this period include Planck's calculation of the blackbody radiation spectrum, Einstein's explanation of the photoelectric effect, Einstein and Debye's work on the specific heat of solids, Bohr and van Leeuwen's proof that classical physics cannot account for diamagnetism, Bohr's model of the hydrogen atom and Arnold Sommerfeld's extension of the Bohr model to include relativistic effects.
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A.T. Forrester, W.E. Parkins, E. Gerjuoy: On the possibility of observing beat frequencies between lines in the visible spectrum, Physical Review, vol. 72, pp. 241–243, 1947 This experiment involved the mixing of the Zeeman components of ordinary incoherent light, that is, the mixing of different components resulting from a split of the spectral line into several components in the presence of a magnetic field due to the Zeeman effect. These light components were mixed at a photoelectric surface, and the electrons emitted from that surface then excited a microwave cavity, which allowed the output signal to be measured in dependence on the magnetic field.
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Losev measured rates of evaporation of benzine from the crystal surface and found it was not accelerated when light was emitted, concluding that the luminescence was a "cold" light not caused by thermal effects. He theorized correctly that the explanation of the light emission was in the new science of quantum mechanics, speculating that it was the inverse of the photoelectric effect explained by Albert Einstein in 1905. He wrote to Einstein about it, but did not receive a reply. In the period of 1924 and 1941, he published a number of articles detailing the function of a solid- state light source that he developed, which would generate light by electroluminescence.
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As described in inventions of Sylvester L. Steffen,; ; ; ; ; ; ; ; and chillcuring is an electrical ventilating process that facilitates the photoelectric after-ripening of bulk stored seeds. The ventilation process is controlled by monitoring the wet-bulb temperature of air around the grain (as measured by evaporative cooling), by which the grain is brought to equilibrium moisture and temperature with atmospheric air. Seed dormancy is better maintained at cooler (chill) atmospheric temperatures, and grain weight and seed vigor are better preserved. The after-ripening of seeds is a biochemical process of carbohydrate/protein stabilization associated with the chemical release of water (H:OH), a reverse process of hydrolysis.
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When she moved to the United States in 1925, she visited a relative who was the Hungarian consul in Cleveland, Ohio. There, she was hired to work in at the Cleveland Clinic Foundation to investigate the energy produced by living organisms. Telkes did some research while working at the foundation, and under the leadership of George Crile, they invented a photoelectric mechanism that could record brain waves and also worked to write a book called Phenomenon of Life. Telkes worked as a biophysicist in the United States; and, from 1939 to 1953, she was involved in solar energy research at Massachusetts Institute of Technology.
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This was a curious design, one where the scanning electron beam would strike the photoelectric cell from the same side where the optical image was cast. Even more importantly, it was a system characterized by an operation based on an entirely new principle, the principle of the accumulation and storage of charges during the entire time between two scansions by the cathode-ray beam. Zworykin and some of the historic camera tubes he developed According to Albert Abramson, Zworykin's experiments started in April 1931, and after the achievement of the first promising experimental transmitters, on October 23, 1931, it was decided that the new camera tube would be named the iconoscope.
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Each globule is very active photoelectrically and constitutes, to all intents and purposes, a minute individual photoelectric cell. Its first image was transmitted in late summer of 1925, and a patent was issued in 1928. However the quality of the transmitted image failed to impress to H P Davis, the general manager of Westinghouse, and Zworykin was asked to work on something useful. A patent for a television system was also filed by Zworykin in 1923, but this file is not a reliable bibliographic source because extensive revisions were done before a patent was issued fifteen years later and the file itself was divided into two patents in 1931.
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While working there, Gutiérrez developed an interest in the photoelectric photometry of austral stars, a subject which she addressed in numerous publications. During the time that she was working at the National Astronomical Observatory, Gutiérrez also became a full faculty member in Faculty of Physical and Mathematical Sciences of the University of Chile. In the late 1950s, Gutiérrez traveled to the United States to study for a PhD in astrophysics, which has obtained in June 1964, becoming the first Chilean to obtain such a degree. In 1965, after having returned to Chile, Gutiérrez, Hugo Moreno León and Claudio Anguita founded a bachelor's degree course in astronomy at the University of Chile.
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The type of device known as a thermionic tube or thermionic valve uses the phenomenon of thermionic emission of electrons from a heated cathode and is used for a number of fundamental electronic functions such as signal amplification and current rectification. Non-thermionic types, such as a vacuum phototube however, achieve electron emission through the photoelectric effect, and are used for such as the detection of light levels. In both types, the electrons are accelerated from the cathode to the anode by the electric field in the tube. The simplest vacuum tube, the diode invented in 1904 by John Ambrose Fleming, contains only a heated electron-emitting cathode and an anode.
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Uniting these scattered ideas, a coherent discipline, quantum mechanics, was formulated between 1925 and 1926, with important contributions from de Broglie, Werner Heisenberg, Max Born, Erwin Schrödinger, Paul Dirac, and Wolfgang Pauli. In the same year as his paper on the photoelectric effect, Einstein published his theory of special relativity, built on Maxwell's electromagnetism. New rules, called Lorentz transformation, were given for the way time and space coordinates of an event change under changes in the observer's velocity, and the distinction between time and space was blurred. It was proposed that all physical laws must be the same for observers at different velocities, i.e.
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By 1904 a total of over 130,000 Nernst lamps had been placed in service throughout the country. In Europe, the lamps were produced by the German Allgemeine Elektrizitäts-Gesellschaft (AEG, General Electricity Company) at Berlin. At the 1900 World's Fair held in Paris the pavilion of the AEG was illuminated by 800 Nernst lamps which was quite spectacular at that time. In addition to their usage for ordinary electric illumination, Nernst lamps were used in one of the first practical long- distance photoelectric facsimile (fax) systems, designed by professor Arthur Korn in 1902, in Allvar Gullstrand's slit lamp (1911) for ophthalmology, for projection and in microscopy.
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It remained located in Copenhagen until 1965, when it was moved to the Smithsonian Astrophysical Observatory, Cambridge, United States. In 1940 Ellis Strömgren was succeeded by his son Bengt Strömgren, who made the pioneering discovery that hydrogen is the most abundant element in the stellar interior. He was also the first to make the correct interpretation of the Hertzsprung–Russell diagram (the relation between the total energy output from a star and its surface temperature was independently found by the Danish chemist and astronomer Ejnar Hertzsprung and the American astronomer Henry Norris Russell). Around 1950, he developed the UVBYß photoelectric system, which is still in use today.
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However, in 1905 Albert Einstein took Planck's black body model to produce his solution to another outstanding problem of the day: the photoelectric effect, wherein electrons are emitted from atoms when they absorb energy from light. Since their existence was theorized eight years previously, phenomena had been studied with the electron model in mind in physics laboratories worldwide. In 1902, Philipp Lenard discovered that the energy of these ejected electrons did not depend on the intensity of the incoming light, but instead on its frequency. So if one shines a little low- frequency light upon a metal, a few low energy electrons are ejected.
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However, it can still be explained using a fully classical description of light, as long as matter is quantum mechanical in nature. If one used Planck's energy quanta, and demanded that electromagnetic radiation at a given frequency could only transfer energy to matter in integer multiples of an energy quantum hf, then the photoelectric effect could be explained very simply. Low-frequency light only ejects low-energy electrons because each electron is excited by the absorption of a single photon. Increasing the intensity of the low-frequency light (increasing the number of photons) only increases the number of excited electrons, not their energy, because the energy of each photon remains low.
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Experimental PCDs for use in CT systems use semiconductor detectors based on either cadmium (zinc) telluride or silicon, neither of which need cryogenic cooling to operate. Cadmium telluride and cadmium zinc telluride detectors have the advantage of high attenuation and relatively high photoelectric-to-Compton ratio for X-ray energies used in CT imaging. This means the detectors can be made thinner and lose less spectral information due to Compton scattering. (Although they still lose spectral information due to K-escape electrons.) However, detectors made of Cadmium telluride (zinc) have longer collection times due to low charge carrier mobility, and thus suffer more from pileup effects.
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The photoelectric effect due to the illumination of the metallic surface extracts electrons (if the energy of the photon is greater than the extraction work) and excites the electrons which the photons don’t have the energy to extract. In a similar process, the electron bombardment of the metal both extracts and excites electrons inside the metal. : I_3-I_2-I_1=I_4 \, If one considers I_1 a constant and increases I_2, it can be observed that I_4 has a maximum of about 150 times I_1. On the other hand, considering I_2 a constant and increasing the intensity of the illumination I_2 the I_4, supplementary current, tends to saturate.
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The invention of a reproducible method for determining hematocrit values allowed Wintrobe to define the red blood cell indices. alt=A complex tube and flask apparatus attached to a measurement station Research into automated cell counting began in the early 20th century. A method developed in 1928 used the amount of light transmitted through a diluted blood sample, as measured by photometry, to estimate the red blood cell count, but this proved inaccurate for samples with abnormal red blood cells. Other attempts, in the 1930s and 1940s, involved photoelectric detectors attached to microscopes, which would count cells as they were scanned; these methods were unsuccessful.
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In the energy range used in CEMS, the incident radiation can interact with the absorber through two kinds of processes: (a) conventional interactions – photoelectric and Compton effects, and (b) nuclear resonant absorption – Mössbauer effect. Due to conventional interactions the beam is attenuated and electrons are emitted from the sample. The nuclear de- excitation following the resonant absorption takes place by emission of either a gamma ray or an internal conversion (IC) electron. In the latter case, the atom is left in an ‘excited’ state with a hole in an inner shell; the energy excess is given away with emission of Auger electrons and/or X-rays.
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The typical adult dose is one 130 mg tablet per 24 hours, supplying 100 mg (100,000 micrograms) of ionic iodine. (The typical daily dose of iodine for normal health is of order 100 micrograms; see "Dietary Intake" below.) Ingestion of this large dose of non-radioactive iodine minimises the uptake of radioactive iodine by the thyroid gland."CDC Radiation Emergencies", U.S. Centers for Disease Control, 11 October 2006, accessed 14 November 2010. Diatrizoic acid, an iodine-containing radiocontrast agent As an element with high electron density and atomic number, iodine absorbs X-rays weaker than 33.3 keV due to the photoelectric effect of the innermost electrons.
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Under the influence of researchers like Scott Forbush, Harry Vestine, Sydney Chapman, and Julius Bartels, Van Allen's interest in low-energy nuclear physics dwindled. He resolved to make geomagnetism, cosmic rays, and solar-terrestrial physics his fields of research, but that transformation had to await the completion of Van Allen's wartime contributions. In the summer of 1940, he joined DTM's national defense efforts with his appointment to a staff position in Section T with the National Defense Research Committee (NDRC) in Washington, D.C. where he worked on the development of photoelectric and radio proximity fuzes, which are detonators that increase the effectiveness of anti-aircraft fire. Another NDRC project later became the atomic bomb Manhattan Project in 1941.
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Henroteau was among the first inventors to propose in 1929 the use of low-velocity electrons for stabilizing the potential of a charge storage plate, but Lubszynski and the EMI team were the first engineers in transmitting a clear and well focused image with such a tube. Another improvement is the use of a semitransparent charge storage plate. The scene image is then projected onto the back side of the plate, while the low- velocity electron beam scans the photoelectric mosaic at the front side. This configurations allows the use of a straight camera tube, because the scene to be transmitted, the charge storage plate, and the electron gun can be aligned one after the other.
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These results demonstrate that graphene/Si heterojunction with interfacial oxide is promising for the development of high detectivity photodetectors. Recently, a graphene/si Schottky photodetector with record-fast response speed (< 25 ns) from wavelength 350 nm to 1100 nm are presented. The photodetectors exhibit excellent long-term stability even stored in air for more than 2 years. These results not only advance the development of high-performance photodetectors based on the graphene/Si Schottky junction, but also have important implications for mass-production of graphene-based photodetector array devices for cost-effective environmental monitoring, medical images, free-space communications, photoelectric smart-tracking, and integration with CMOS circuits for emerging interest-of-things applications, etc.
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In April 1925, German professor Max Dieckmann and his student Rudolf Hell applied for a patent for a device named Lichtelektrische Bildzerlegerröhre für Fernseher (Photoelectric Image Dissector Tube for Television). A patent was issued in October 1927, and their experiments were announced in the magazines Discovery and Popular Radio, but they failed to reduce it to practice. In 1951, Hell claimed that he had made a tube but could not get it to function, since at the time there was an insufficient knowledge of electron optics, the manipulation of an electron beam by electric or magnetic fields. American television pioneer Philo T. Farnsworth invented the first functional image dissector in 1927, submitting a patent application on January 7, 1927.
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Another revolutionary development of the 20th century was quantum theory, which emerged from the seminal contributions of Max Planck (1856–1947) (on black-body radiation) and Einstein's work on the photoelectric effect. In 1912, a mathematician Henri Poincare published Sur la théorie des quanta . He introduced the first non-naïve definition of quantization in this paper. The development of early quantum physics followed by a heuristic framework devised by Arnold Sommerfeld (1868–1951) and Niels Bohr (1885–1962), but this was soon replaced by the quantum mechanics developed by Max Born (1882–1970), Werner Heisenberg (1901–1976), Paul Dirac (1902–1984), Erwin Schrödinger (1887–1961), Satyendra Nath Bose (1894–1974), and Wolfgang Pauli (1900–1958).
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He received the 1921 Nobel Prize in Physics "for his services to theoretical physics, and especially for his discovery of the law of the photoelectric effect", a pivotal step in the evolution of quantum theory. Einstein published more than 300 scientific papers along with over 150 non-scientific works.. His non-scientific works include: About Zionism: Speeches and Lectures by Professor Albert Einstein (1930), "Why War?" (1933, co-authored by Sigmund Freud), The World As I See It (1934), Out of My Later Years (1950), and a book on science for the general reader, The Evolution of Physics (1938, co-authored by Leopold Infeld). Einstein's intellectual achievements and originality have made the word "Einstein" synonymous with "genius".
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Whilst ordinary professor in physics at the University of Palermo, he studied the conduction of heat and electricity in bismuth. From 1885 to 1889 in Padua, he studied the photoelectric effect. Towards the end of 1889 he was called to the University of Bologna, his home city, where he worked for the rest of his life on subjects such as the Zeeman effect, 'Roentgen rays', magnetism and the results of Michelson's experiments.A. Righi, La Materia radiante e i raggi magnetici, Zanichelli (1909) spark transmitter (left) and coherer detector Righi used in his experiments His most well known work is his 1890s investigations of Hertzian waves (radio waves), which had been discovered in 1887.
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In 2010, a different team found that every time they observe the exoplanet at a certain position in its orbit, they also detected X-ray flares. In 2019, astronomers analyzed data from Arecibo Observatory, MOST, and the Automated Photoelectric Telescope, in addition to historical observations of the star at radio, optical, ultraviolet, and X-ray wavelengths to examine these claims. They found that the previous claims were exaggerated and the host star failed to display many of the brightness and spectral characteristics associated with stellar flaring and solar active regions, including sunspots. Their statistical analysis also found that many stellar flares are seen regardless of the position of the exoplanet, therefore debunking the earlier claims.
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An extended doorway bridge plate, or wheelchair ramp, in a low-floor MAX car The second series of Siemens SD660 cars, TriMet's "Type 3" MAX light rail vehicle, are outwardly identical to the Type 2 cars in design, the primary difference being various technical upgrades. Siemens installed an improved air-conditioning system, more ergonomic seats and automatic passenger counters using photoelectric sensors above the doorways. The Type 3 cars were the first to wear the transit agency's newer (2002-adopted) paint scheme. Purchased for the opening of the Yellow Line in May 2004, delivery of the Type 3 series began in February 2003, and the vehicles began to enter service in September 2003.
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Philipp Eduard Anton von Lenard (; 7 June 1862 – 20 May 1947) was a Hungarian- born German physicist and the winner of the Nobel Prize for Physics in 1905 for his work on cathode rays and the discovery of many of their properties. One of his most important contributions was the experimental realization of the photoelectric effect. He discovered that the energy (speed) of the electrons ejected from a cathode depends only on the wavelength, and not the intensity of, the incident light. Lenard was a nationalist and anti-Semite; as an active proponent of the Nazi ideology, he supported Adolf Hitler in the 1920s and was an important role model for the "Deutsche Physik" movement during the Nazi period.
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Optoelectronic streak cameras work by directing the light onto a photocathode, which when hit by photons produces electrons via the photoelectric effect. The electrons are accelerated in a cathode ray tube and pass through an electric field produced by a pair of plates, which deflects the electrons sideways. By modulating the electric potential between the plates, the electric field is quickly changed to give a time-varying deflection of the electrons, sweeping the electrons across a phosphor screen at the end of the tube. A linear detector, such as a charge-coupled device (CCD) array is used to measure the streak pattern on the screen, and thus the temporal profile of the light pulse.
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In 1946 he returned to Cambridge to be based at the Cambridge Observatory as Senior Observer and was able to complete the observational work on his PhD In 1947 he transferred to Dunsink Observatory in Ireland where he stayed until 1953. At Dunsink he produced a number of papers concerning the photoelectric recording of stellar occultations and stellar scintillation , topics that led ultimately to the technologies that support the discovery of exoplanets and the construction of large ground-based optical telescopes respectively. He was also intensely practical and gained a significant reputation for the design and implementation of novel instruments. At Dunsink these skills were put to good effect in building it up as a modern observatory.
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On this atomic scale, which is governed by Planck's constant, the properties of a system are very different than that of bulk matter. This diverging behavior leads to emerging phenomena that cannot be explained or accounted for in classical terms. Quantum mechanics can thus predict or explain a variety of phenomena in a variety of systems, from the well established photoelectric effect to the transmission of information via entangled quantum objects. These phenomena arise from the concepts of quantum mechanics; for instance, the wave-particle duality allows electron to tunnel through classically unsurmountable barriers, the condensation of electrons into Cooper pairs, which is the basis of superconductivity, is made possible only because of Pauli's exclusion principle.
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In 1900, Einstein's paper "Folgerungen aus den Capillaritätserscheinungen" ("Conclusions from the Capillarity Phenomena") was published in the journal Annalen der Physik. On 30 April 1905, Einstein completed his thesis, with Alfred Kleiner, Professor of Experimental Physics, serving as pro-forma advisor. As a result, Einstein was awarded a PhD by the University of Zürich, with his dissertation A New Determination of Molecular Dimensions. Also in 1905, which has been called Einstein's annus mirabilis (amazing year), he published four groundbreaking papers, on the photoelectric effect, Brownian motion, special relativity, and the equivalence of mass and energy, which were to bring him to the notice of the academic world, at the age of 26.
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Atoms can be excited by a high-energy beam of charged particles such as electrons (in an electron microscope for example), protons (see PIXE) or a beam of X-rays (see X-ray fluorescence, or XRF or also recently in transmission XRT). These methods enable elements from the entire periodic table to be analysed, with the exception of H, He and Li. In electron microscopy an electron beam excites X-rays; there are two main techniques for analysis of spectra of characteristic X-ray radiation: energy-dispersive X-ray spectroscopy (EDS) and wavelength dispersive X-ray spectroscopy (WDS). In X-Ray Transmission (XRT), the equivalent atomic composition (Zeff) is captured based on photoelectric and Compton effects.
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By the late 1960s the aircraft business had already been transferred to other GE plants located in Johnson City, New York, and Erie, Pennsylvania. By 1974, the adjustable speed drives business had been transferred to GE's plant in Erie, PA. The photoelectric business was absorbed by the General Purpose Control Department in Bloomington, Illinois, and the power systems components, consisting of static exciters and power regulators, were transferred to the Industry Control Department in Salem, VA. The residual products remaining in Specialty Control were now reduced to the Terminet printers and the relay business. The name Specialty Control now became Data Communications Products Department and, at one time, Data Communications Products Business Department.
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Work has involved design changes to traffic lanes, improved pedestrian and cycle crossings, refurbishment of walkways beneath the mainline railway viaduct, and the construction of a bus station, completed in December 2004 featuring an undulating steel-frame canopy and ribbed steel walls. An interesting feature of the canopy is a series of photoelectric cells generating electricity to offset the energy used by the bus station. Vauxhall Cross bus station will be redeveloped to create a new mixed-use development consisting of offices, hotels, and shopping areas. The project will be managed by Great Marlborough Estates and has an apparent budget of £600 million, and is estimated to make the developers over £45 million.
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The first new instruments were delivered in the spring of 1914. The 65 cm refractorZeiss refractor telescope at AIP — the first big astronomical instrument manufactured by the famous enterprise of Carl Zeiss Jena — was mounted in 1915, whereas the completion of the 122 cm reflector telescope122 cm Reflecting Telescope formerly in Babelsberg was delayed until 1924 by the First World War. Struve died in 1920 from an accident, and his successor was Paul Guthnick, who introduced in 1913 photoelectric photometry into astronomy as the first objective method of measuring the brightness of stars. When the 122 cm telescope (at this time the second largest in the world) was finished, the Babelsberg Observatory was the best-equipped observatory of Europe.
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Smoke Detector mounted on the ceiling A smoke detector is a device that senses smoke, typically as an indicator of fire. Commercial security devices issue a signal to a fire alarm control panel as part of a fire alarm system, while household smoke detectors, also known as smoke alarms, generally issue a local audible or visual alarm from the detector itself or several detectors if there are multiple smoke detectors interlinked. Smoke detectors are housed in plastic enclosures, typically shaped like a disk about in diameter and thick, but shape and size vary. Smoke can be detected either optically (photoelectric) or by physical process (ionization); detectors may use either, or both, methods.
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The received light intensity will be reduced due to scattering from particulates of smoke, air-borne dust, or other substances; the circuitry detects the light intensity and generates the alarm if it is below a specified threshold, potentially due to smoke. In other types, typically chamber types, the light is not directed at the sensor, which is not illuminated in the absence of particles. If the air in the chamber contains particles (smoke or dust), the light is scattered and some of it reaches the sensor, triggering the alarm. According to the National Fire Protection Association (NFPA), "photoelectric smoke detection is generally more responsive to fires that begin with a long period of smoldering".
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As sunlight, due to atmosphere's absorption, does not provide much ultraviolet light, the light rich in ultraviolet rays used to be obtained by burning magnesium or from an arc lamp. At the present time, mercury-vapor lamps, noble-gas discharge UV lamps and radio-frequency plasma sources, ultraviolet lasers, and synchrotron insertion device light sources prevail.alt=The classical setup to observe the photoelectric effect includes a light source, a set of filters to monochromatize the light, a vacuum tube transparent to ultraviolet light, an emitting electrode (E) exposed to the light, and a collector (C) whose voltage VC can be externally controlled. A positive external voltage is used to direct the photoemitted electrons onto the collector.
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This frequency is called the threshold frequency. Increasing the frequency of the incident beam increases the maximum kinetic energy of the emitted photoelectrons, and the stopping voltage has to increase. The number of emitted electrons may also change because the probability that each photon results in an emitted electron is a function of photon energy. An increase in the intensity of the same monochromatic light (so long as the intensity is not too high), which is proportional to the number of photons impinging on the surface in a given time, increases the rate at which electrons are ejected—the photoelectric current I—but the kinetic energy of the photoelectrons and the stopping voltage remain the same.
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When the electroscope is negatively charged, there is an excess of electrons and the leaves are separated. If low-wavelength, high-frequency light (such as ultraviolet light obtained from an arc lamp, or by burning magnesium, or by using an induction coil between zinc or cadmium terminals to produce sparking) shines on the cap, the electroscope discharges, and the leaves fall limp. If, however, the frequency of the light waves is below the threshold value for the cap, the leaves will not discharge, no matter how long one shines the light at the cap. In 1887, Heinrich Hertz observed the photoelectric effect and reported on the production and reception of electromagnetic waves.
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The electromagnetic field may be thought of in a more 'coarse' way. Experiments reveal that in some circumstances electromagnetic energy transfer is better described as being carried in the form of packets called quanta (in this case, photons) with a fixed frequency. Planck's relation links the photon energy E of a photon to its frequency f through the equation: :E= \, h f where h is Planck's constant, and f is the frequency of the photon . Although modern quantum optics tells us that there also is a semi-classical explanation of the photoelectric effect—the emission of electrons from metallic surfaces subjected to electromagnetic radiation—the photon was historically (although not strictly necessarily) used to explain certain observations.
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Popular Photography, Volume 65 Number 6; June 2001. The first autoexposure still camera was the non-SLR Kodak Super Kodak Six-20 (USA) of 1938 with a mechanical system controlling both aperture and shutter speed via trapped-needle method coupled to external selenium photoelectric cell.Herbert Keppler, "Inside Straight: Film Festival: Old film cameras are no doorstops," pp 46–47. Popular Photography & Imaging, Volume 71 Number 8; August 2007. Schneider, "The 10 most important cameras of the 20th century." p 87Schneider, "Classic Cameras; The Top 20 Cameras of All-Time Countdown: Schneider's List, The Next Five—Do You Agree?" pp 146, 148, 150, 152–153. Shutterbug, Volume 37 Number 9 Issue 454; July 2008.
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Steven Gandy, "Zunow: premiere Japanese independent fast lens maker" from retrieved 5 January 2006 Note, the 1954 version of the Ihagee Exakta VX (East Germany) 35 mm SLR introduced an external auto-diaphragm lens system using a spring-loaded shutter button plunger connection rod.Aguila & Rouah, pp 65–67, 118Wade, Collector's Guide. p 152 ;1959: Zeiss Ikon Contarex (West Germany): first SLR with a built-in light meter coupled to a viewfinder exposure control indicator – a galvanometer needle pointer. It had an external, circular selenium photoelectric cell mounted above the lens;Herbert Keppler, "SLR: Can you see the difference in pictures shot with a super-high-quality modern lens and an inexpensive old SLR lens?" pp 26–27.
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Gavrilă completed in 1977 his previous work on the relativistic theory of the photoelectric effect in the inner atomic orbitals that he had begun in his Ph.D. thesis in 1958; thus, he applied radiative corrections to his previous calculationsJames McEnnan and M. Gavrilă: Radiative corrections to the atomic photoeffect, Physical Review A, 15 (4), 1537–1556 (1977). James McEnnan and M. Gavrilă: Radiative corrections to the high-frequency end of the bremsstrahlung spectrum, Physical Review A, 15 (4), 1557–1562 (1977). He also investigated two-photon excitations and the elastic photon scattering amplitude in the hydrogen ground state,.Mihai Gavrilă: Elastic Scattering of Photons by a Hydrogen Atom, Physical Review, 163 (1), 147–155 (1967)M.
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The demonstration given (sometime in late 1925 or early 1926) by Zworykin was far from a success with the Westinghouse management, even though it showed the possibilities inherent in a system based on the cathode ray tube. He was told by management to "devote his time to more practical endeavours," yet continued his efforts to perfect his system. As attested by his doctoral dissertation of 1926, earning him a PhD from the University of Pittsburgh, his experiments were directed at improving the output of photoelectric cells. There were, however, limits to how far one could go along these lines, and so, in 1929, Zworykin returned to vibrating mirrors and facsimile transmission, filing patents describing these.
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This use of fluorescent materials to make a viewing scope is how fluoroscopy got its name. As the X-rays pass through the patient, they are attenuated by varying amounts as they pass through or reflect off the different tissues of the body, casting an X-ray shadow of the radiopaque tissues (such as bone tissue) on the fluorescent screen. Images on the screen are produced as the unattenuated or mildly attenuated X-rays from radiolucent tissues interact with atoms in the screen through the photoelectric effect, giving their energy to the electrons. While much of the energy given to the electrons is dissipated as heat, a fraction of it is given off as visible light.
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Diffraction pattern of the protein thaumatin in its tetragonal crystal form, recorded on a PILATUS 6M at the HZB MX beamline BL14.1. PILATUS is the name of a series of x-ray detectors originally developed by the Paul Scherrer Institute at the Swiss Light Source and further developed and commercialized by DECTRIS. The PILATUS detectors are based on hybrid photon counting (HPC) technology, by which X-rays are converted to electrical signals by the photoelectric effect in a semiconductor sensor layer--either silicon or cadmium telluride--which is subject to a substantial bias voltage. The electric signals are counted directly by a series of cells in an ASIC bonded to the sensor.
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During her career, Beale was granted funding from the John and Mary R. Markle Foundation (1942–1946) for advancement in serology, and the American Association for the Advancement of Science (1942) "for a study of the photoelectric titration of plant viruses". In 1948, she was promoted to both plant pathologist at the Boyce Thompson Institute, and to research associate at Columbia University. Beale retired from these positions in 1952 and began a prolific monograph on plant viruses. The project was well funded across several sources including the American Tobacco Corporation, the Boyce Thompson Institute, the R.J. Reynolds Tobacco Company, the National Institutes of Health, the National Library of Medicine, and received USDA and Agricultural Research Service support.
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Houston began his college education in 1916 at Ohio State University (OSU) where he earned his baccalaureate degree in physics. He served in the military during 1918 and 1919. After teaching physics at the University of Dubuque for one year, he entered graduate studies at the University of Chicago and studied under Albert A. Michelson, who had won the Nobel Prize in Physics in 1907, and Robert Millikan who would win the Nobel Prize in Physics in 1923 for his measurement of the charge on the electron and for his work on the photoelectric effect. It was at this time that Houston began his experimental work on the fine structure of hydrogen and wss awarded an M.S. in 1922.
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After his study and research in Germany, Houston returned to Caltech and served as an assistant professor (1927–1929), associate professor (1929–1931), and professor (1931–1946). He again took up his experimental work on spectroscopy and the theory of electrons in atoms and solids. His work on the Zeeman effect resulted in a correction to the accepted value of the e/m ratio, as well as stimulating R. T. Birge and J. W. M. Dumond to work up a consistent set of precise atomic constants. In solid-state physics he studied the surface photoelectric effect and made the first suggestion and analysis of the use of soft x-rays to investigate the energy bands of solids.
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In 2008, a team of astronomers first described how as the exoplanet orbiting HD 189733 A reaches a certain place in its orbit, it causes increased stellar flaring. In 2010, a different team found that every time they observe the exoplanet at a certain position in its orbit, they also detected X-ray flares. Theoretical research since 2000 suggested that an exoplanet very near to the star that it orbits may cause increased flaring due to the interaction of their magnetic fields, or because of tidal forces. In 2019, astronomers analyzed data from Arecibo Observatory, MOST, and the Automated Photoelectric Telescope, in addition to historical observations of the star at radio, optical, ultraviolet, and X-ray wavelengths to examine these claims.
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Eta Carinae light curve in several different passbands Photometers employ the use of specialised standard passband filters across the ultraviolet, visible, and infrared wavelengths of the electromagnetic spectrum. Any adopted set of filters with known light transmission properties is called a photometric system, and allows the establishment of particular properties about stars and other types of astronomical objects. Several important systems are regularly used, such as the UBV system (or the extended UBVRI system), near infrared JHK or the Strömgren uvbyβ system. Historically, photometry in the near-infrared through short-wavelength ultra-violet was done with a photoelectric photometer, an instrument that measured the light intensity of a single object by directing its light onto a photosensitive cell like a photomultiplier tube.
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While he was gone, Kunz and another Illinois physicists W.F. Schulz successfully tested a photoelectric cell photometer at the Observatory. Upon his return from sabbatical in August 1913, Stebbins ended his pioneering work with the selenium cell and began working with Kunz on the new photometer. A number of other notable astronomical discoveries occurred at the observatory through the years. In 1915 Stebbins' object of study became the star involved in Myers' first big discovery at the observatory, Beta Lyrae. He thus began an aggressive research program produced a series of papers in the Astrophysical Journal on eclipsing binaries Lambda Tauri, Algol, 1H Cassiopeiae (HR 8926), ellipsoidal variables π5 Orionis, and b Persei, and Nova Aquilae (V603 Aquilae) in 1918.
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Mechanical Manufacturing and Its Automation Mechanical Manufacturing and Its Automation is a key discipline at ministerial level. A research team composed of 15 professors, 8 associate professors engages itself in the discipline. Major research interests include: A. CAD/CAM and Enterprise Informatization; B. Manufacture Automation Technology and System; C. Test, Measurement and Diagnosis of Mechanical Manufacture; D. CIMS; E. New Manufacture Technology and Equipment. Signals and Information Processing Signals and Information Processing focuses on the techniques of information processing, identifying and reconstructing, the theory and technology of information processing, technology of information processing and reconstructing, technology of information real-time processing and identifying, technology of information mixing, the photoelectric technology, technology of information safety and information confrontation, and image processing technology.
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As a second application of the proposed hypothesis, Ishiwara considered the problem of the photoelectric effect, obtaining a linear relationship between the electron energy and the radiation frequency in accordance with the Einstein formula. Later in the same year Ishiwara put forward another hypothesis, according to which the product of the energy of the atom and the period of electron motion in the stationary state should be equal to the integer number of Planck constants. In 1918, he linked the postulate proposed three years earlier to the theory of adiabatic invariants. Around the same time, analogous rules for quantizing systems of many degrees of freedom were independently obtained by William Wilson and Sommerfeld and are usually called the Sommerfeld quantum conditions.
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The first documented photomultiplier demonstration dates to the early 1934 accomplishments of an RCA group based in Harrison, NJ. Harley Iams and Bernard Salzberg were the first to integrate a photoelectric-effect cathode and single secondary emission amplification stage in a single vacuum envelope and the first to characterize its performance as a photomultiplier with electron amplification gain. These accomplishments were finalized prior to June 1934 as detailed in the manuscript submitted to Proceedings of the Institute of Radio Engineers (Proc. IRE). The device consisted of a semi-cylindrical photocathode, a secondary emitter mounted on the axis, and a collector grid surrounding the secondary emitter. The tube had a gain of about eight and operated at frequencies well above 10 kHz.
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The red light is used as a probe, while the infrared light provides a relatively stable baseline for comparison. Photoelectric cells in a spectrophotometer device worn on the forehead measure the amount of each wavelength of light reflected by cerebral blood flow in the activated cortical tissue and send the data to a computer, which then calculates the ratio of red to infrared light and translates it into a visual signal of corresponding to oxygenation level on a graphical interface the patient can see. The key nutrient monitored by NIR is oxygen. In NIR, as the ratio of oxygenated hemoglobin (HbO2) to deoxygenated hemoglobin (Hb) increases, the blood becomes less and less translucent and scatters more of the red light, instead of absorbing it.
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Commercial single-photon avalanche diode module for optical photons A single- photon avalanche diode (SPAD) is a solid-state photodetector within the same family as photodiodes and avalanche photodiodes (APDs), while also being fundamentally linked with basic diode behaviours. As with photodiodes and APDs, a SPAD is based around a semi-conductor p-n junction that can be illuminated with ionizing radiation such as gamma, x-rays, beta and alpha particles along with a wide portion of the electromagnetic spectrum from ultraviolet (UV) through the visible wavelengths and into the infrared (IR). In a photodiode, with a low reverse bias voltage, the leakage current changes linearly with absorption of photons, i.e. the liberation of current carriers (electrons and/or holes) due to the internal photoelectric effect.
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In 2008, a team of astronomers first described how as the exoplanet orbiting HD 189733 A reaches a certain place in its orbit, it causes increased stellar flaring. In 2010, a different team found that every time they observe the exoplanet at a certain position in its orbit, they also detected X-ray flares. Theoretical research since 2000 suggested that an exoplanet very near to the star that it orbits may cause increased flaring due to the interaction of their magnetic fields, or because of tidal forces. In 2019, astronomers analyzed data from Arecibo Observatory, MOST, and the Automated Photoelectric Telescope, in addition to historical observations of the star at radio, optical, ultraviolet, and X-ray wavelengths to examine these claims.
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Fresnel lens solar collectorNorthrup’s break- through technology was a collector Roof-lens Solar Collector that used a long curved acrylic fresnel lens to concentrate or focus sunlight at a theoretical ratio of approximately 12 to 1 onto a linear flat copper tube, coated with a variant of Dr. Tabor's “black chrome” absorptive surface. The array, approximately 10’ long, tracked the movement of the sun during the day (east to west), automatically, with the elevation generally fixed (at approximately the same angle from horizontal as the latitude of the installation). The tracking device was ingenious – it consisted of two photoelectric cells at the base of a tube with a baffle between them. Current from the cells went to a control board that controlled the tracking motor.
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One of the G-15's primary output devices is the typewriter with an output speed of about 10 characters per second for numbers (and lower-case hexadecimal characters u-z) and about three characters per second for alphabetical characters. The machine's limited storage precludes much output of anything but numbers; occasionally, paper forms with pre-printed fields or labels were inserted into the typewriter. A faster typewriter unit was also available. The high-speed photoelectric paper tape reader (250 hexadecimal digits per second on five-channel paper tape for the PR-1; 400 characters from 5-8 channel tape for the PR-2) read programs (and occasionally saved data) from tapes that were often mounted in cartridges for easy loading and unloading.
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The first works of Louis de Broglie (early 1920s) were performed in the laboratory of his older brother Maurice and dealt with the features of the photoelectric effect and the properties of x-rays. These publications examined the absorption of X-rays and described this phenomenon using the Bohr theory, applied quantum principles to the interpretation of photoelectron spectra, and gave a systematic classification of X-ray spectra. The studies of X-ray spectra were important for elucidating the structure of the internal electron shells of atoms (optical spectra are determined by the outer shells). Thus, the results of experiments conducted together with Alexandre Dauvillier, revealed the shortcomings of the existing schemes for the distribution of electrons in atoms; these difficulties were eliminated by Edmund Stoner.
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Shenzhen Zhongzhi kay Technology Co., Ltd. is YIYNOVA (Yu Qi Technology) was founded in mainland China with technology research and product development-oriented high-tech enterprises. The company developed the handwriting display, handwritten one computer, and handwriting tablet computers Tablet products, using pressure sensitive electromagnetic pen interactive technology to achieve the world's advanced level, including handwritten computer products in the "2010 Shenzhen Optoelectronic Display Week" and the "Shenzhen (International) TV Festival "exhibition received the 2009 China photoelectric display industry Product Excellence Award of the" Innovation Design Award. " Company R & D team is the first group engaged in electromagnetic handwriting technology development staff, also has eight years of experience in developing and manufacturing LCD backlight, as well as 14 years of experience in product development and manufacturing displays.
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This approach dates back to the late 1930s when photon sources were restricted to low-energy x-ray units (Mayneord 1937). The exponent of 2.94 relates to an empirical formula for the photoelectric process which incorporates a ‘constant’ of 2.64 x 10−26, which is in fact not a constant but rather a function of the photon energy. A linear relationship between Z2.94 has been shown for a limited number of compounds for low-energy x-rays, but within the same publication it is shown that many compounds do not lie on the same trendline (Spiers et al. 1946). As such, for polyenergetic photon sources (in particular, for applications such as radiotherapy), the effective atomic number varies significantly with energy (Taylor et al. 2008).
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The Bohr model of the atom fixed the problem of energy loss from radiation from a ground state (by declaring that there was no state below this), and more importantly explained the origin of spectral lines. Rutherford–Bohr model of the hydrogen atom. After Bohr's use of Einstein's explanation of the photoelectric effect to relate energy levels in atoms with the wavelength of emitted light, the connection between the structure of electrons in atoms and the emission and absorption spectra of atoms became an increasingly useful tool in the understanding of electrons in atoms. The most prominent feature of emission and absorption spectra (known experimentally since the middle of the 19th century), was that these atomic spectra contained discrete lines.
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The natural outdoor exposure in the United Kingdom ranges from 0.1 to 0.5 µSv/h with significant increase around known nuclear and contaminated sites.ENVIRONMENT AGENCY UK Radioactivity in Food and the Environment, 2012 Natural exposure to gamma rays is about 1 to 2 mSv per year, and the average total amount of radiation received in one year per inhabitant in the USA is 3.6 mSv.United Nations Scientific Committee on the Effects of Atomic Radiation Annex E: Medical radiation exposures – Sources and Effects of Ionizing – 1993, p. 249, New York, UN There is a small increase in the dose, due to naturally occurring gamma radiation, around small particles of high atomic number materials in the human body caused by the photoelectric effect.
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In 1938, she became a Huff Research Fellow at Bryn Mawr College, which allowed her to receive her PhD for her thesis on nuclear physics, "Photoelectric Cross Section of the Deuteron". She subsequently took up a teaching position at the University of Tennessee in 1939, becoming an assistant professor in 1941. At a conference in New York in 1938, Way presented a paper, "Nuclear Quadrupole and Magnetic Moments", in which she examined deformation of a spinning atomic nucleus under three models, including Niels Bohr's liquid drop model. She followed this up with a closer examination of the liquid drop model in a paper entitled "The Liquid- Drop Model and Nuclear Moments", in which she showed that the resulting cigar- shaped nucleus could be unstable.
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The Gladstone–Dale relation requires a particle model of light because the continuous wave-front required by wave theory cannot be maintained if light encounters atoms or molecules that maintain a local electric structure with a characteristic refractivity. Similarly, the wave theory cannot explain the photoelectric effect or absorption by individual atoms and one requires a local particle of light (see wave–particle duality). A local model of light consistent with these electrostatic refraction calculations occurs if the electromagnetic energy is restricted to a finite region of space. An electric-charge monopole must occur perpendicular to dipole loops of magnetic flux, but if local mechanisms for propagation are required, a periodic oscillatory exchange of electromagnetic energy occurs with transient mass.
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In many fields they are functionally identical, differing for terrestrial studies only in origin of the radiation. In astronomy, however, where radiation origin often cannot be reliably determined, the old energy division has been preserved, with X-rays defined as being between about 120 eV and 120 keV, and gamma rays as being of any energy above 100 to 120 keV, regardless of source. Most astronomical "gamma-ray astronomy" are known not to originate in nuclear radioactive processes but, rather, result from processes like those that produce astronomical X-rays, except driven by much more energetic electrons. Photoelectric absorption is the dominant mechanism in organic materials for photon energies below 100 keV, typical of classical X-ray tube originated X-rays.
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In 2008, a team of astronomers first described how as the exoplanet orbiting HD 189733 A reaches a certain place in its orbit, it causes increased stellar flaring. In 2010, a different team found that every time they observe the exoplanet at a certain position in its orbit, they also detected X-ray flares. Theoretical research since 2000 suggested that an exoplanet very near to the star that it orbits may cause increased flaring due to the interaction of their magnetic fields, or because of tidal forces. In 2019, astronomers combined data from Arecibo Observatory, MOST, and the Automated Photoelectric Telescope, in addition to historical observations of the star at radio, optical, ultraviolet, and X-ray wavelengths to examine these claims.
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While Lee de Forest struggled to market Phonofilm, Charles A. Hoxie's Pallophotophone had success as an optical recording device through the support of General Electric. The Pallophotophone utilized the entire width of unsprocketed 35mm Kodak monochrome film to record and replay multiple audio tracks. Unlike Phonofilm, this optical sound technology used a photoelectric process which captured audio wave forms generated by a vibrating mirror galvanometer, and was the first effective multitrack recording system, predating magnetic tape multitrack recorders by at least 20 years. From the early 1920s until the early 30s, GE broadcast over 1,000 Pallophotophone recordings from its Schenectady, New York radio station, WGY, including speeches by presidents Calvin Coolidge and Herbert Hoover, and inventor- businessmen Thomas Edison and Henry Ford.
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She later credited the publication of her discovery as a stroke of luck – the star is in that state only 2-3% of the time -- that substantially raised her profile within the astronomical community, contributing to her career progression. After her work at the Yerkes and McDonald Observatories, one of Roman's earliest publications was a 1955 catalog of high velocity stars, published in the Astrophysical Journal Supplement Series. She documented new “spectral types, photoelectric magnitudes and colors, and spectroscopic parallaxes for about 600 high- velocity stars.” One result of this was that her “UV excess” method became widely used by astronomers to select stars with more heavier elements using only the colors of the stars rather than having to take spectra.
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Vedral uses an Italo Calvino philosophical story about a tarot- like card game as the kernel for his metaphor of conscious life arriving in medias res to a pre-existing contextual reality. In this game the individual observers/players (Vedral suggests: quantum physics, thermodynamics, biology, sociology, economics, philosophy) lay down cards with ambiguous meanings as an attempt to communicate messages to deduce meaning out of the other players' interactions. The results (information) of previous rounds establish contextual rules for observers/players in subsequent rounds. The point of this game is not established until the last card has been played as later cards can change the meaning of previous events, as in the case of the quantum explanation for the photoelectric effect instantly disproving classical physics.
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The constant speed of light in a vacuum (customarily described with a lowercase letter "c") can be derived from Maxwell's equations, which are consistent with the theory of special relativity. Albert Einstein's 1905 theory of special relativity, however, which follows from the observation that the speed of light is constant no matter how fast the observer is moving, showed that the theoretical result implied by Maxwell's equations has profound implications far beyond electromagnetism on the very nature of time and space. In another work that departed from classical electro-magnetism, Einstein also explained the photoelectric effect by utilizing Max Planck's discovery that light was transmitted in 'quanta' of specific energy content based on the frequency, which we now call photons. Starting around 1927, Paul Dirac combined quantum mechanics with the relativistic theory of electromagnetism.
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Nuclei with zero-spin and high excitation energies (more than about 1.022 MeV) are also unable to rid themselves of energy by (single) gamma emission due to the constraint imposed by the conservation of momentum, but they do have sufficient decay energy to decay by pair production. E0 rules In this type of decay, an electron and positron are both emitted from the atom at the same time, and conservation of angular momentum is solved by having these two product particles spin in opposite directions. The internal conversion process should not be confused with the similar photoelectric effect. When a gamma ray emitted by the nucleus of an atom hits a different atom, it may be absorbed producing a photoelectron of well-defined energy (this used to be called "external conversion").
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In June 1908, the scientific journal Nature published a letter in which Alan Archibald Campbell-Swinton, fellow of the Royal Society (UK), discussed how a fully electronic television system could be realized by using cathode ray tubes (or "Braun" tubes, after their inventor, Karl Braun) as both imaging and display devices. He noted that the "real difficulties lie in devising an efficient transmitter", and that it was possible that "no photoelectric phenomenon at present known will provide what is required". A cathode ray tube was successfully demonstrated as a displaying device by the German Professor Max Dieckmann in 1906, his experimental results were published by the journal Scientific American in 1909. Campbell-Swinton later expanded on his vision in a presidential address given to the Röntgen Society in November 1911.
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Tubes quenched with hydrocarbons often fail due to coating of the electrodes with polymerization products, before the gas itself can be depleted; simple gas refill won't help, washing the electrodes to remove the deposits is necessary. Low ionization efficiency is sometimes deliberately sought; mixtures of low pressure hydrogen or helium with organic quenchers are used in some cosmic rays experiments, to detect heavily ionizing muons and electrons. Argon, krypton and xenon are used to detect soft x-rays, with increasing absorption of low energy photons with decreasing atomic mass, due to direct ionization by photoelectric effect. Above 60-70 keV the direct ionization of the filler gas becomes insignificant, and secondary photoelectrons, Compton electrons or electron-positron pair production by interaction of the gamma photons with the cathode material become the dominant ionization initiation mechanisms.
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Photoelectric V light curve for AM Canum Venaticorum over a 330-minute period During 1939–40, a survey for faint white dwarfs was carried out using an Schmidt telescope at Palomar observatory. Part of the survey was made around the north galactic pole in order to exclude stars of stellar classifications O, B, and A, as these higher mass, shorter-lived stars tend to be concentrated along the plane of the Milky Way where new star formation occurs. Out of the stars observed, a list of faint blue stars was constructed by Milton L. Humason and Fritz Zwicky in 1947, with their blue hue suggesting a relatively high effective temperature. The 29th star on their list, HZ 29, was found to have the most peculiar spectrum out of the set.
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The naval weapon was intended to bring down low flying aircraft with a trailing wire to the end of which was attached an explosive mine; however, the land based system was intended to have a high explosive warhead, detonated by a specially designed photoelectric proximity fuse. The rocket itself was propelled by special solvent-free cordite, which was initially manufactured at Bishopton in Scotland; in December 1940, a new propellant factory was commissioned at Ranskill, which was in production by the start of 1942.Edgerton, David (2012), Britain's War Machine: Weapons, Resources, and Experts in the Second World War Penguin Books, (pp.108-110) The metal working firm G. A. Harvey and Co of Greenwich was given the contract to manufacture the rocket bodies and over 1,000 had been made by September 1940.
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Members of England's blind football team travelled to Los Angeles in November 2011 to promote the sport in the United States, and took part in a day's training with former England captain David Beckham. The trip was organised by supermarket chain Sainsbury's as part of their sponsorship deal with the footballer. Blind cricket, which is played basically the same as conventional cricket but using larger stumps and wickets and a white ball so that players may see it much more easily, is also played at the college, and RNC has its own cricket team, which competes in the British Blind Sport (BBS) National Cricket League. The college also features acoustic shooting, a sport which uses air rifles fitted with photoelectric cells which convert light reflected from targets into sound.
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392 (Aug 2008), studiovoice.jp . Retrieved February 16, 2012 and book publications in Japan.Itaru Mita, "THIRD DECADE 1998-2009: 2005_MY CAT IS AN ALIEN", Ambient Music 1969-2009, Studio Voice Books / INFAS Books (2009), pg.213-216, . Retrieved February 16, 2012 In 2005 the Opalio brothers moved their recording studio from Torino to a remote and secret location in the Western Alps they call 'Alien Zone', where Roberto introduced his wordless vocalizations as a leading instrument. In this regard English writer Ken Hollings, author of MCIAA cover article in The Wire, states: From the vastness of the Alpine territory, the brothers released new key works, including Black Shadows From Jupiter, Vol.I & II (Opax Records, 2005 / Elliptical Noise, 2009), Photoelectric Season (Elliptical Noise, 2010), and Fragments Suspended In Time (Opax Records, 2010).
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A significant amount of the energy released by fusion reactions is composed of electromagnetic radiations, essentially X-rays due to Bremsstrahlung. Those X-rays can not be converted into electric power with the various electrostatic and magnetic direct energy converters listed above, and their energy is lost. Whereas more classical thermal conversion has been considered with the use of a radiation/boiler/energy exchanger where the X-ray energy is absorbed by a working fluid at temperatures of several thousand degrees, more recent research done by companies developing nuclear aneutronic fusion reactors, like Lawrenceville Plasma Physics (LPP) with the Dense Plasma Focus, and Tri Alpha Energy, Inc. with the Colliding Beam Fusion Reactor (CBFR), plan to harness the photoelectric and Auger effects to recover energy carried by X-rays and other high-energy photons.
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Following the end of the war Woolley redirected the Commonwealth Observatory from solar research towards the study of stars and galaxies. It took time to get the old and unused telescopes back up to working condition: they had to be overhauled and refurbished, and in one case rebuilt from scrap. Woolley got funding approval from the Prime Minister for construction of a 74-inch telescope, but it would not be finished for years. Gascoigne began to work in the nascent field of photoelectric photometry, using electrical devices to measure the brightness of stars more accurately than had been possible using photographic techniques. In 1951, with equipment brought by visiting astronomer Gerald Kron from California's Lick Observatory, he observed Cepheid variable stars, which are used to measure astronomical distances.
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Near the beginning of his career, Einstein thought that Newtonian mechanics was no longer enough to reconcile the laws of classical mechanics with the laws of the electromagnetic field. This led him to develop his special theory of relativity during his time at the Swiss Patent Office. There is evidence—from Einstein's own writings—that he collaborated with his first wife, Mileva Marić on this work. The decision to publish only under his name seems to have been mutual, but the exact reason is unknown. In 1905, called his annus mirabilis (miracle year), he published four groundbreaking papers, which attracted the attention of the academic world; the first outlined the theory of the photoelectric effect, the second paper explained Brownian motion, the third paper introduced special relativity, and the fourth mass-energy equivalence.
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Modern Photography, Volume 33, Number 12; December 1969. Matanle, pp 181–183 Film is rated at a particular "speed" sensitivity. It needs a specific amount of light to form an image. The Weston Universal 617 (USA) helped introduce light exposure metering by a handheld selenium photoelectric device to sense the ambient light in 1932,"Weston – The Company and The Man" retrieved 22 October 2008"Weston 617" retrieved 22 October 2008Scott Bilotta, "Weston Electrical Instrument Corp. Model 617 Exposure Meter" retrieved 1 December 2008Peres, p 775Stroebel and Zakia, p 290 but miniature light meters built into the camera that gave TTL readings were a great leap forward in convenienceHorder, pp 189–194 introduced by the Feinwerk Technik Mec 16SB (West Germany) non-SLR subminiature (10×14 mm frames on 16 mm film) camera in 1960.
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The legacy of the David Dunlap Observatory continues in the Dunlap Institute for Astronomy & Astrophysics, a research institute at the University of Toronto established in 2008. The DDO is the site of a number of important studies, including pioneering measurements of the distance to globular clusters, providing the first direct evidence that Cygnus X-1 was a black hole, and the discovery that Polaris was stabilizing and appeared to be "falling out" of the Cepheid variable category.Polaris - The Story Continues Photoelectric Photometry Newsletter, American Association of Variable Star Observers, May 1998 Located on a hill, yet still relatively close to sea level at altitude, and now surrounded by subdivisions, its optical astronomy ability has been reduced as compared to other remote observatory sites around the world. On July 31, 2019, the DDO was announced as a National Historic Site of Canada.
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A "photoelectrochemical cell" is one of two distinct classes of device. The first produces electrical energy similarly to a dye-sensitized photovoltaic cell, which meets the standard definition of a photovoltaic cell. The second is a photoelectrolytic cell, that is, a device which uses light incident on a photosensitizer, semiconductor, or aqueous metal immersed in an electrolytic solution to directly cause a chemical reaction, for example to produce hydrogen via the electrolysis of water. Both types of device are varieties of solar cell, in that a photoelectrochemical cell's function is to use the photoelectric effect (or, very similarly, the photovoltaic effect) to convert electromagnetic radiation (typically sunlight) either directly into electrical power, or into something which can itself be easily used to produce electrical power (hydrogen, for example, can be burned to create electrical power, see photohydrogen).
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In 1905, Albert Einstein presented the hypothesis that the photoelectric effect could be explained if a beam of light was composed of a stream of discrete particles (photons), each with an energy () the energy (E) of each photon being equal to the frequency (f) multiplied by Planck's constant (h). Translated in Later, in 1916 Albert Einstein also showed that the recoil of molecules during the emission and absorption of photons was consistent with, and necessary for, a quantum description of thermal radiation processes. Each photon acts as if it imparts a momentum impulse p equal to its energy divided by the speed of light, (). and a nearly identical version Translated here and in In 1925, shortly before the development of the full mathematical description of quantum mechanics, Born drew Einstein's attention to the then-new idea of "de Broglie's waves".
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Notable results were included in "A General Catalogue of Photoelectric Magnitudes and Colours in the UBV System of 3578 Galaxies, Brighter than the 16-th V Magnitude (1936-1982)" by G. Longo, Antoinette de Vaucouleurs and H.G. Corwin (1983) (see also Gérard de Vaucouleurs), with significant part of its data obtained from Belogradchik observatory. During the 1990s, beside fast stellar electro-photometry of variable stars, it was also a base for meticulous observations of minor bodies of the Solar System, including the famous Shoemaker-Levy 9 comet encounter with Jupiter in July 1994. In recent years Romanian astronomers have jointly used the observatory for an astrometry project, linked to the Gaia programme, prior to its launch in December 2013. It was by that time an automatic seismograph was mounted in an adjacent isolated compartment, where it serves both Romanian and Bulgarian seismologists.
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The researches of Langevin and those of Eugene Bloch have shown that the greater part of the Lenard effect is certainly due to the Hertz effect. The Lenard effect upon the gas itself nevertheless does exist. Refound by J. J. Thomson and then more decisively by Frederic Palmer, Jr., the gas photoemission was studied and showed very different characteristics than those at first attributed to it by Lenard. In 1900, while studying black-body radiation, the German physicist Max Planck suggested in his "On the Law of Distribution of Energy in the Normal Spectrum" paper that the energy carried by electromagnetic waves could only be released in packets of energy. In 1905, Albert Einstein published a paper advancing the hypothesis that light energy is carried in discrete quantized packets to explain experimental data from the photoelectric effect.
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The paper proposed a simple description of light quanta, or photons, and showed how they explained such phenomena as the photoelectric effect. His simple explanation in terms of absorption of discrete quanta of light agreed with experimental results. It explained why the energy of photoelectrons was dependent only on the frequency of the incident light and not on its intensity: at low-intensity, the high- frequency source could supply a few high energy photons, whereas at high- intensity, the low-frequency source would supply no photons of sufficient individual energy to dislodge any electrons. This was an enormous theoretical leap, but the concept was strongly resisted at first because it contradicted the wave theory of light that followed naturally from James Clerk Maxwell's equations of electromagnetism, and more generally, the assumption of infinite divisibility of energy in physical systems.
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In 1914, he opened the Case Research Lab to experiment with the photoelectric properties of various materials, leading to the development of the Thallofide (short for thallium oxysulfide) Cell, a light-sensitive vacuum tube. The Thallofide tube was originally used by the United States Navy in a top secret ship-to-ship infrared signaling system developed at Case's lab with his assistant Earl Sponable. Case and Sponable's system was first tested off the shores of New Jersey in 1917, and attending the test was Thomas Edison, contracted by the Navy to evaluate new technologies. The test was a success, and the U.S. Navy used the system during and after World War I. Contemporary with the work of Case and Sponable was Charles A. Hoxie's Pallophotophone (from Greek roots meaning "shaking light sound"), manufactured by General Electric (GE).
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In Hong Kong, physics is a subject for public examination. Local students in Form 6 take the public exam of Hong Kong Diploma of Secondary Education (HKDSE). Compare to the other syllabus include GCSE, GCE etc which learn wider and boarder of different topics, the Hong Kong syllabus is learning more deeply and more challenges with calculations. Topics are narrow down to a smaller amount compared to the A-level due to the insufficient teaching hours at secondary schools in Hong Kong, which include temperature, heat, internal energy, change of state, gases, position, motion, force, projectile motion, work, energy, power, momentum, uniform circular motion, gravitation, wave, light, sound, electrostatics, circuits, electromagnetism, radiation, radioactivity, atomic model, nuclear energy, universe, astronomy, stars, Rutherford model, photoelectric effect, Bohr model, particles, nanoscopic scale, building, transportation, renewable energy sources, eye, ear, non-ionizing radiation and ionizing radiation etc.
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For example, the light, or electromagnetic radiation emitted or absorbed by an atom has only certain frequencies (or wavelengths), as can be seen from the line spectrum associated with the chemical element represented by that atom. The quantum theory shows that those frequencies correspond to definite energies of the light quanta, or photons, and result from the fact that the electrons of the atom can have only certain allowed energy values, or levels; when an electron changes from one allowed level to another, a quantum of energy is emitted or absorbed whose frequency is directly proportional to the energy difference between the two levels. The photoelectric effect further confirmed the quantization of light. In 1924, Louis de Broglie proposed that not only do light waves sometimes exhibit particle-like properties, but particles may also exhibit wave-like properties.
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Farnsworth image dissector tube from 1931 An image dissector is a camera tube that creates an "electron image" of a scene from photocathode emissions (electrons) which pass through a scanning aperture to an anode, which serves as an electron detector.Horowitz, Paul and Winfield Hill, The Art of Electronics, Second Edition, Cambridge University Press, 1989, pp. 1000-1001. . Among the first to design such a device were German inventors Max Dieckmann and Rudolf Hell, who had titled their 1925 patent application Lichtelektrische Bildzerlegerröhre für Fernseher (Photoelectric Image Dissector Tube for Television). The term may apply specifically to a dissector tube employing magnetic fields to keep the electron image in focus, an element lacking in Dieckmann and Hell's design, and in the early dissector tubes built by American inventor Philo Farnsworth. Dieckmann and Hell submitted their application to the German patent office in April 1925, and a patent was issued in October 1927.
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1926 Gilbert N. Lewis letter which brought the word "photon" into common usage The word quanta (singular quantum, Latin for how much) was used before 1900 to mean particles or amounts of different quantities, including electricity. In 1900, the German physicist Max Planck was studying black-body radiation, and he suggested that the experimental observations, specifically at shorter wavelengths, would be explained if the energy stored within a molecule was a "discrete quantity composed of an integral number of finite equal parts", which he called "energy elements". In 1905, Albert Einstein published a paper in which he proposed that many light- related phenomena—including black-body radiation and the photoelectric effect—would be better explained by modelling electromagnetic waves as consisting of spatially localized, discrete wave-packets.. An English translation is available from Wikisource. He called such a wave-packet the light quantum (German: das Lichtquant).
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Compton published a paper in the Physical Review explaining the phenomenon: A quantum theory of the scattering of X-rays by light elements. The Compton effect can be understood as high-energy photons scattering in-elastically off individual electrons, when the incoming photon gives part of its energy to the electron, then the scattered photon has lower energy and lower frequency and longer wavelength according to the Planck relation: : E = h u = h f which gives the energy E of the photon in terms of frequency f or ν, and Planck's constant h ( = ). The wavelength change in such scattering depends only upon the angle of scattering for a given target particle. This was an important discovery during the 1920s when the particle (photon) nature of light suggested by the Photoelectric effect was still being debated, the Compton experiment gave clear and independent evidence of particle-like behavior.
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Polish inventor Jan Szczepanik patented a color television system in 1897, using a selenium photoelectric cell at the transmitter and an electromagnet controlling an oscillating mirror and a moving prism at the receiver. But his system contained no means of analyzing the spectrum of colors at the transmitting end, and could not have worked as he described it.R.W. Burns, Television: An International History of the Formative Years, IET, 1998, p. 98. . Another inventor, Hovannes Adamian, also experimented with color television as early as 1907. The first color television project is claimed by him,Western technology and Soviet economic development: 1945 to 1965, by Antony C. Sutton, Business & Economics – 1973, p. 330 and was patented in Germany on 31 March 1908, patent No. 197183, then in Britain, on 1 April 1908, patent No. 7219,The History of Television, 1880–1941, by Albert Abramson, 1987, p.
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363–397The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science, Series 6, volume 2, pages 1–40 (1901) The two "dark clouds" he was alluding to were confusion surrounding how matter moves through the aether (including the puzzling results of the Michelson–Morley experiment) and indications that the Law of Equipartition in statistical mechanics might break down. Two major physical theories were developed during the twentieth century starting from these issues: for the former, the theory of relativity; for the second, quantum mechanics. Albert Einstein, in 1905, published the so-called "Annus Mirabilis papers", one of which explained the photoelectric effect, based on Max Planck's discovery of energy quanta which was the foundation of quantum mechanics, another of which described special relativity, and the last of which explained Brownian motion in terms of statistical mechanics, providing a strong argument for the existence of atoms.
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RAN Station 9, Pinkenba (Myrtletown) was listed on the Queensland Heritage Register on 17 July 2008 having satisfied the following criteria. The place is important in demonstrating the evolution or pattern of Queensland's history. The surviving concrete huts and the concrete remnants of the quarters and mess building at RAN Station 9 at Pinkenba (Myrtletown) are important in demonstrating the pattern of Queensland's history, being surviving evidence of the efforts made to defend Moreton Bay and the Brisbane River against enemy ships and submarines during World War II. The indicator loop and photo-electric beam installation at Myrtletown was part of an interlocking system of naval defences for Moreton Bay, which incorporated coastal artillery batteries, indicator loops, controlled minefields, ASDIC (anti-submarine sonar detection) devices, Fairmile anti-submarine motor launches, a photoelectric (PE) beam and an anti-submarine boom. The place demonstrates rare, uncommon or endangered aspects of Queensland's cultural heritage.
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The production and commercialization of the super-Emitron and image iconoscope in Europe were not affected by the patent war between Zworykin and Farnsworth, because Dieckmann and Hell had priority in Germany for the invention of the image dissector, having submitted a patent application for their Lichtelektrische Bildzerlegerröhre für Fernseher (Photoelectric Image Dissector Tube for Television) in Germany in 1925, two years before Farnsworth did the same in the United States. The image iconoscope (Superikonoskop) became the industrial standard for public broadcasting in Europe from 1936 until 1960, when it was replaced by the vidicon and plumbicon tubes. Indeed, it was the representative of the European tradition in electronic tubes competing against the American tradition represented by the image orthicon. The German company Heimann produced the Superikonoskop for the 1936 Berlin Olympic Games, later Heimann also produced and commercialized it from 1940 to 1955, finally the Dutch company Philips produced and commercialized the image iconoscope and multicon from 1952 to 1958.
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In this work, Reynolds sought to bring conceptual elements in the text to the fore with the aid of spatial movement of sound. > I began my own efforts to address space in modest fashion, in a music- > theater composition [The Emperor of Ice-Cream] intended for the ONCE > Festivals but not actually premiered until 1965 in the context of the Nuova > Consonanza Festival of Franco Evangelisti's, in Rome. … So, in the case of > [Wallace] Stevens's line "And spread it so as to cover her face," the eight > singers, arrayed across the front of the stage, pass the phonemes of the > associated melodic phrase back and forth by fading in and out successively. Later, in Japan, Reynolds worked with engineer Junosuke Okuyama to build a "photo-cell sound distributor," which used a matrix of photoelectric cells to move sounds around a quadraphonic setup, with the aid of a flashlight as a kind of controller.
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Anton Z. Capri, "Quips, quotes, and quanta: an anecdotal history of physics" (World Scientific 2007) p.96 Since Millikan's work formed some of the basis for modern particle physics, it is ironic that he was rather conservative in his opinions about 20th century developments in physics, as in the case of the photon theory. Another example is that his textbook, as late as the 1927 version, unambiguously states the existence of the ether, and mentions Einstein's theory of relativity only in a noncommittal note at the end of the caption under Einstein's portrait, stating as the last in a list of accomplishments that he was "author of the special theory of relativity in 1905 and of the general theory of relativity in 1914, both of which have had great success in explaining otherwise unexplained phenomena and in predicting new ones." Millikan is also credited with measuring the value of Planck's constant by using photoelectric emission graphs of various metals.
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The cathode (at left) and the anode (right) are Pt needles which have been melted into the crystal. From R.W. Pohl, Electromagnetism, from the 10th edition (1944) on. Photoelectric observations – however not from surfaces, as in Berlin, but rather in bulk insulators – were started by Pohl together with his assistant Bernhard Gudden in 1919. (The research work from this period was described in detail in Biographische Notizen von Robert Wichard Pohl: "Erinnerungen an die Anfänge der Festkörperphysik in Göttingen und Lebenslauf und politische Haltung von R. W. Pohl", R. Pohl und H. Pick(first part).) They discovered that diamond crystals become electrically conducting after irradiation with light."Über lichtelektrische Leitfähigkeit von Diamanten", B. Gudden und R. Pohl, im September 1919 Zeitschrift für Physik Band 3 (1920), p. 123 Later, they observed the same effect in the alkali halide sodium chloride; however only after it had been colored as a result of X-ray irradiation.
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The history of quantum chemistry also goes through the 1838 discovery of cathode rays by Michael Faraday, the 1859 statement of the black-body radiation problem by Gustav Kirchhoff, the 1877 suggestion by Ludwig Boltzmann that the energy states of a physical system could be discrete, and the 1900 quantum hypothesis by Max Planck that any energy radiating atomic system can theoretically be divided into a number of discrete energy elements ε such that each of these energy elements is proportional to the frequency ν with which they each individually radiate energy and a numerical value called Planck's constant. Then, in 1905, to explain the photoelectric effect (1839), i.e., that shining light on certain materials can function to eject electrons from the material, Albert Einstein postulated, based on Planck's quantum hypothesis, that light itself consists of individual quantum particles, which later came to be called photons (1926). In the years to follow, this theoretical basis slowly began to be applied to chemical structure, reactivity, and bonding.
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It is based on the photoelectric effect originally observed by Heinrich Hertz in 1887 and later explained by Albert Einstein in 1905 that when a material is shone by light, the electrons can absorb photons and escape from the material with the kinetic energy: E = hf-\phi, where hf is the incident photon energy, \phi the work function of the material. Since the kinetic energy of ejected electrons are highly associated with the internal electronic structure, by analyzing the photoelectron spectroscopy one can realize the fundamental physical and chemical properties of the material, such as the type and arrangement of local bonding, electronic structure and chemical composition. In addition, because electrons with different momentum will escape from the sample in different directions, angle-resolved photoemission spectroscopy is widely used to provide the dispersive energy- momentum spectrum. The photoemission experiment is conducted using synchrotron radiation light source with typical photon energy of 20 – 100 eV.
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The production and commercialization of the super-Emitron and image iconoscope in Europe were not affected by the patent war between Zworykin and Farnsworth, because Dieckmann and Hell had priority in Germany for the invention of the image dissector, having submitted a patent application for their Lichtelektrische Bildzerlegerröhre für Fernseher (Photoelectric Image Dissector Tube for Television) in Germany in 1925, two years before Farnsworth did the same in the United States. The image iconoscope (Superikonoskop) became the industrial standard for public broadcasting in Europe from 1936 until 1960, when it was replaced by the vidicon and plumbicon tubes. Indeed, it was the representative of the European tradition in electronic tubes competing against the American tradition represented by the image orthicon. The German company Heimann produced the Superikonoskop for the 1936 Berlin Olympic Games, later Heimann also produced and commercialized it from 1940 to 1955; finally the Dutch company Philips produced and commercialized the image iconoscope and multicon from 1952 to 1958.
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This tube is essentially identical to the super-Emitron. The production and commercialization of the super-Emitron and image iconoscope in Europe were not affected by the patent war between Zworykin and Farnsworth, because Dieckmann and Hell had priority in Germany for the invention of the image dissector, having submitted a patent application for their Lichtelektrische Bildzerlegerröhre für Fernseher (Photoelectric Image Dissector Tube for Television) in Germany in 1925, two years before Farnsworth did the same in the United States. The image iconoscope (Superikonoskop) became the industrial standard for public broadcasting in Europe from 1936 until 1960, when it was replaced by the vidicon and plumbicon tubes. Indeed, it was the representative of the European tradition in electronic tubes competing against the American tradition represented by the image orthicon. The German company Heimann produced the Superikonoskop for the 1936 Berlin Olympic Games, later Heimann also produced and commercialized it from 1940 to 1955, finally the Dutch company Philips produced and commercialized the image iconoscope and multicon from 1952 to 1958.
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Einstein proposed that gravitation is a result of masses (or their equivalent energies) curving ("bending") the spacetime in which they exist, altering the paths they follow within it. Einstein argued that the speed of light was a constant in all inertial reference frames and that electromagnetic laws should remain valid independent of reference frame—assertions which rendered the ether "superfluous" to physical theory, and that held that observations of time and length varied relative to how the observer was moving with respect to the object being measured (what came to be called the "special theory of relativity"). It also followed that mass and energy were interchangeable quantities according to the equation E=mc2. In another paper published the same year, Einstein asserted that electromagnetic radiation was transmitted in discrete quantities ("quanta"), according to a constant that the theoretical physicist Max Planck had posited in 1900 to arrive at an accurate theory for the distribution of blackbody radiation—an assumption that explained the strange properties of the photoelectric effect.
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The basic ideas of quantum theory were introduced in 1900 by Max Planck (1858–1947), who was awarded the Nobel Prize for Physics in 1918 for his discovery of the quantified nature of energy. The quantum theory (which previously relied in the "correspondence" at large scales between the quantized world of the atom and the continuities of the "classical" world) was accepted when the Compton Effect established that light carries momentum and can scatter off particles, and when Louis de Broglie asserted that matter can be seen as behaving as a wave in much the same way as electromagnetic waves behave like particles (wave–particle duality). Werner Heisenberg (1901–1976) In 1905, Einstein used the quantum theory to explain the photoelectric effect, and in 1913 the Danish physicist Niels Bohr used the same constant to explain the stability of Rutherford's atom as well as the frequencies of light emitted by hydrogen gas. The quantized theory of the atom gave way to a full-scale quantum mechanics in the 1920s.
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Intermediate film system for Remote Truck (1934), 1 - movie camera; 2 - film processor; 3 - washing bath; 4 - film drying compartment; 5 - telecine; 6 - monitor; 7 - video output; 8 - sewage; 9 - plumbing. The intermediate film system was a television process in which motion picture film was processed almost immediately after it was exposed in a camera, then scanned by a television scanner, and transmitted over the air. This system was used principally in Britain and Germany where television cameras were not sensitive enough to use reflected light, but could transmit a suitable image when a bright light was shown through motion picture film directly into the camera lens.The alternative was to use a flying spot scanner, with a bank of photoelectric cells combining their strengths, but the darkened television studio required made it unsuitable for large casts or sets, or outdoor use. John Logie Baird began developing the process in 1932, borrowing the idea of Georg Oskar Schubert from his licensees in Germany, where it was demonstrated by Fernseh AG in 1932 and used for broadcasting in 1934.
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Implosion mechanism In early 1941, with World War II raging in Europe but the United States not yet a belligerent, Neddermeyer joined a team led by Charles C. Lauritsen and William A. Fowler at the Department of Terrestrial Magnetism at the Carnegie Institution of Washington, and then at the National Bureau of Standards in Washington, D.C., that worked on the photoelectric proximity fuze. After this work was successfully completed, Neddermeyer was recruited by Oppenheimer to work at the Manhattan Project's Los Alamos Laboratory. Neddermeyer was an early advocate for the development of an implosion technique for assembling a critical mass in an atomic bomb. Although implosion was suggested by Richard Tolman as early as 1942, and discussed in the introductory lectures given to Los Alamos scientists by Robert Serber, Neddermeyer was one of the first to urge its full development. Unable to find much initial enthusiasm for the concept among his fellow Los Alamos scientists, Neddermeyer presented the first substantial technical analysis of implosion in late April 1943.
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Originally designed so his powers would eventually kill him, Nate was an Omega-level mutant who had the ability to tap into the enormous psychic resources of the astral plane in order to manipulate matter and energy at vast scales until his powers were burnt out by the Omega Machine.New Mutants Vol 3 #27 The Omega Machine, designed by Dark Beast, greatly diminished Nate's once incredible psychic powers including telepathy, precognition, and telekinesis. He could use his telepathy to read and control multiple minds at once and even read residual thought imprints left on objects touched by people (psychometry), communicate with others by broadcasting his thoughts, create illusions by altering the perceptions of others, fire psionic blasts that could scramble an opponent's thought processes (causing the victim either intense pain, or rendering them unconscious), project his mind into the astral plane and even pull the astral projections of other telepaths into the physical world, and sense dimensional rifts or anomalies. He once even used the photoelectric transmission of a Shi'ar hologram to psionically connect his mind with that of Lilandra over an unknown interstellar distance.
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When power was applied and the front cover closed, a spindle engaged the center hole of the disc and a motor-driven idler wheel spun the disc on the spindle. The power switch itself was mechanically linked to the disc's drive system; lowering the front panel dropped the spindle and disconnected power to the instrument, allowing the program discs to be changed without the need to fully power down. A broad, flat, white plastic cleaning tool with a purple, simulated velvet cleaning surface was supplied with each Optigan to allow periodic cleaning of the photoelectric cell, located near the rear of the instrument. Thirty-seven tracks were sustained or repeatedly percussive notes in the timbre of a particular instrument and were played through a standard three-octave piano- style keyboard with the right hand; twenty-one were of a live band or soloist playing chords in different keys arranged per the circle of fifths, specifically B-flat, F, C, G, D, A and E major, minor, and diminished and were played with the left hand in much the style of a chord organ or accordion.
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Marie Skłodowska-Curie (1867–1934) At the end of the 19th century, physics had evolved to the point at which classical mechanics could cope with highly complex problems involving macroscopic situations; thermodynamics and kinetic theory were well established; geometrical and physical optics could be understood in terms of electromagnetic waves; and the conservation laws for energy and momentum (and mass) were widely accepted. So profound were these and other developments that it was generally accepted that all the important laws of physics had been discovered and that, henceforth, research would be concerned with clearing up minor problems and particularly with improvements of method and measurement. However, around 1900 serious doubts arose about the completeness of the classical theories—the triumph of Maxwell's theories, for example, was undermined by inadequacies that had already begun to appear—and their inability to explain certain physical phenomena, such as the energy distribution in blackbody radiation and the photoelectric effect, while some of the theoretical formulations led to paradoxes when pushed to the limit. Prominent physicists such as Hendrik Lorentz, Emil Cohn, Ernst Wiechert and Wilhelm Wien believed that some modification of Maxwell's equations might provide the basis for all physical laws.
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Even though Einstein's photon hypothesis could explain in a simple way the photoelectric effect, as well as conservation of energy in processes of de- excitation of an atom followed by excitation of a neighboring one, Bohr had always been reluctant to accept the reality of photons, his main argument being the problem of reconciling the existence of photons with the phenomenon of interference; # The impossibility to account for conservation of energy in a process of de-excitation of an atom followed by excitation of a neighboring one. This impossibility followed from Slater's probabilistic assumption, which did not imply any correlation between processes going on in different atoms. As Max Jammer puts it, this refocussed the theory "to harmonize the physical picture of the continuous electromagnetic field with the physical picture, not as Slater had proposed of light quanta, but of the discontinuous quantum transitions in the atom." Bohr and Kramers hoped to be able to evade the photon hypothesis on the basis of ongoing work by Kramers to describe "dispersion" (in present-day terms inelastic scattering) of light by means of a classical theory of interaction of radiation and matter.
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By the early 1930s, the movie industry had almost universally adopted sound- on-film technology, in which the audio signal to be recorded was used to modulate a light source that was imaged onto the moving film through a narrow slit, allowing it to be photographed as variations in the density or width of a "soundtrack" running along a dedicated area of the film. The projector used a steady light and a photoelectric cell to convert the variations back into an electrical signal, which was amplified and sent to loudspeakers behind the screen. The adoption of sound-on-film also helped movie-industry audio engineers to make rapid advances in the process we now know as "multi- tracking", by which multiple separately-recorded audio sources (such as voices, sound effects and background music) can be replayed simultaneously, mixed together, and synchronised with the action on film to create new 'blended' audio tracks of great sophistication and complexity. One of the best-known examples of a 'constructed' composite sound from that era is the famous "Tarzan yell" created for the series of Tarzan movies starring Johnny Weissmuller.
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