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Nernst Lamp
The Nernst lamp was an early form of incandescent lamp. Construction Nernst lamps did not use a glowing tungsten filament. Instead, they used a ceramic rod that was heated to incandescence. Because the rod (unlike tungsten wire) would not further oxidize when exposed to air, there was no need to enclose it within a vacuum or noble gas environment; the burners in Nernst lamps could operate exposed to the air and were only enclosed in glass to isolate the hot incandescent emitter from its environment. A ceramic of zirconium oxide – yttrium oxide was used as the glowing rod. Efficiency Developed by the German physicist and chemist Walther Nernst in 1897 at the University of Göttingen, these lamps were about twice as efficient as carbon-filament lamps and emitted a more "natural" light (more similar in spectrum to daylight). The lamps were quite successfully marketed for a time, although they eventually lost out to the more efficient tungsten-filament incandescent light b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pittsburgh, Pennsylvania
Pittsburgh ( ) is a city in the Commonwealth of Pennsylvania, United States, and the county seat of Allegheny County. It is the most populous city in both Allegheny County and Western Pennsylvania, the second-most populous city in Pennsylvania behind Philadelphia, and the 68th-largest city in the U.S. with a population of 302,971 as of the 2020 census. The city anchors the Pittsburgh metropolitan area of Western Pennsylvania; its population of 2.37 million is the largest in both the Ohio Valley and Appalachia, the second-largest in Pennsylvania, and the 27th-largest in the U.S. It is the principal city of the greater Pittsburgh–New Castle–Weirton combined statistical area that extends into Ohio and West Virginia. Pittsburgh is located in southwest Pennsylvania at the confluence of the Allegheny River and the Monongahela River, which combine to form the Ohio River. Pittsburgh is known both as "the Steel City" for its more than 300 steel-related businesses and as the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Light Sources
This is a list of sources of light, the visible part of the electromagnetic spectrum. Light sources produce photons from another energy source, such as heat, chemical reactions, or conversion of mass or a different frequency of electromagnetic energy, and include light bulbs and stars like the Sun. Reflectors (such as the moon, cat's eyes, and mirrors) do not actually produce the light that comes from them. Incandescence Incandescence is the emission of light from a hot body as a result of its temperature. * * Combustion Lamps * (obsolete) * * * * (error) * * * * *s *s * (obsolete) *s * Other * * * *s * * * * * * * * * Nuclear and high-energy particle * * ** ** * * * * * Celestial and atmospheric *Astronomical objects **Sun (sunlight, solar radiation) *** *** **Star (Starlight) ***Nova / supernova / hypernova *** **** *** ** *** *** *** *** *** * **Meteor *** ** *** *Lightning ( Plasma) ** ** ** ** * * Luminescence Luminescence is emissi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Globar
A Globar is used as thermal light source for infrared spectroscopy. The preffered material for making Globar is silicon carbide that is shaped as rods or arches of various sizes. When inserted into a circuit that provides it with electric current, it emits radiation from ~ 2 to 50 micrometres wavelength via the Joule heating phenomenon. Globars are used as infrared sources for spectroscopy because their spectral behavior corresponds approximately to that of a Planck radiator (i.e. a black body). Alternative infrared sources are Nernst lamps, coils of chrome–nickel alloy or high-pressure mercury lamps. The technical term ''Globar'' is an English portmanteau word consisting of ''glow'' and ''bar''. The term ''glowbar'' is sometimes used synonymously in English (which is an incorrect spelling in the strict sense). The ''American Resistor Company'' in Milwaukee, Wisconsin, had word and lettering ''Globar'' registered as a trademark (in a special decorative script font) with the U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Globar
A Globar is used as thermal light source for infrared spectroscopy. The preffered material for making Globar is silicon carbide that is shaped as rods or arches of various sizes. When inserted into a circuit that provides it with electric current, it emits radiation from ~ 2 to 50 micrometres wavelength via the Joule heating phenomenon. Globars are used as infrared sources for spectroscopy because their spectral behavior corresponds approximately to that of a Planck radiator (i.e. a black body). Alternative infrared sources are Nernst lamps, coils of chrome–nickel alloy or high-pressure mercury lamps. The technical term ''Globar'' is an English portmanteau word consisting of ''glow'' and ''bar''. The term ''glowbar'' is sometimes used synonymously in English (which is an incorrect spelling in the strict sense). The ''American Resistor Company'' in Milwaukee, Wisconsin, had word and lettering ''Globar'' registered as a trademark (in a special decorative script font) with the U ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicon Carbide
Silicon carbide (SiC), also known as carborundum (), is a hard chemical compound containing silicon and carbon. A semiconductor, it occurs in nature as the extremely rare mineral moissanite, but has been mass-produced as a powder and crystal since 1893 for use as an abrasive. Grains of silicon carbide can be bonded together by sintering to form very hard ceramics that are widely used in applications requiring high endurance, such as car brakes, car clutches and ceramic plates in bulletproof vests. Large single crystals of silicon carbide can be grown by the Lely method and they can be cut into gems known as synthetic moissanite. Electronic applications of silicon carbide such as light-emitting diodes (LEDs) and detectors in early radios were first demonstrated around 1907. SiC is used in semiconductor electronics devices that operate at high temperatures or high voltages, or both. Natural occurrence Naturally occurring moissanite is found in only minute quantities in cer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IR Spectroscopy
Infrared spectroscopy (IR spectroscopy or vibrational spectroscopy) is the measurement of the interaction of infrared radiation with matter by absorption, emission, or reflection. It is used to study and identify chemical substances or functional groups in solid, liquid, or gaseous forms. It can be used to characterize new materials or identify and verify known and unknown samples. The method or technique of infrared spectroscopy is conducted with an instrument called an infrared spectrometer (or spectrophotometer) which produces an infrared spectrum. An IR spectrum can be visualized in a graph of infrared light absorbance (or transmittance) on the vertical axis vs. frequency, wavenumber or wavelength on the horizontal axis. Typical units of wavenumber used in IR spectra are reciprocal centimeters, with the symbol cm−1. Units of IR wavelength are commonly given in micrometers (formerly called "microns"), symbol μm, which are related to the wavenumber in a reciprocal way. A co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ophthalmology
Ophthalmology ( ) is a surgical subspecialty within medicine that deals with the diagnosis and treatment of eye disorders. An ophthalmologist is a physician who undergoes subspecialty training in medical and surgical eye care. Following a medical degree, a doctor specialising in ophthalmology must pursue additional postgraduate residency training specific to that field. This may include a one-year integrated internship that involves more general medical training in other fields such as internal medicine or general surgery. Following residency, additional specialty training (or fellowship) may be sought in a particular aspect of eye pathology. Ophthalmologists prescribe medications to treat eye diseases, implement laser therapy, and perform surgery when needed. Ophthalmologists provide both primary and specialty eye care - medical and surgical. Most ophthalmologists participate in academic research on eye diseases at some point in their training and many include research as par ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allvar Gullstrand
Allvar Gullstrand (5 June 1862 – 28 July 1930) was a Swedish ophthalmologist and optician. Life Born at Landskrona, Sweden, Gullstrand was professor (1894–1927) successively of eye therapy and of optics at the University of Uppsala. He applied the methods of physical mathematics to the study of optical images and of the refraction of light in the eye. For this work, he received the Nobel Prize in Physiology or Medicine in 1911. Gullstrand is noted also for his research on astigmatism and for improving the ophthalmoscope and corrective lenses for use after removal of a cataract from the eye. He was elected a member of the Royal Swedish Academy of Sciences in 1905, and served on the Academy's Prize Committee for Physics. While serving on the committee, he used his position to block Albert Einstein from receiving a Nobel Prize in Physics for his theory of relativity, which Allvar believed to be wrong. Gullstrand married Signe Breitholtz (1862–1946) in 1885. Due to the mat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exposition Universelle (1900)
The Exposition Universelle of 1900, better known in English as the 1900 Paris Exposition, was a world's fair held in Paris, France, from 14 April to 12 November 1900, to celebrate the achievements of the past century and to accelerate development into the next. It was held at the esplanade of Les Invalides, the Champ de Mars, the Trocadéro and at the banks of the Seine between them, with an additional section in the Bois de Vincennes, and it was visited by more than 50 million people. Many international congresses and other events were held within the framework of the Exposition, including the 1900 Summer Olympics. Many technological innovations were displayed at the Fair, including the '' Grande Roue de Paris'' ferris wheel, the ''Rue de l'Avenir'' moving sidewalk, the first ever regular passenger trolleybus line, escalators, diesel engines, electric cars, dry cell batteries, electric fire engines, talking films, the telegraphone (the first magnetic audio recorder), ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Berlin
Berlin ( , ) is the capital and List of cities in Germany by population, largest city of Germany by both area and population. Its 3.7 million inhabitants make it the European Union's List of cities in the European Union by population within city limits, most populous city, according to population within city limits. One of Germany's States of Germany, sixteen constituent states, Berlin is surrounded by the Brandenburg, State of Brandenburg and contiguous with Potsdam, Brandenburg's capital. Berlin's urban area, which has a population of around 4.5 million, is the second most populous urban area in Germany after the Ruhr. The Berlin/Brandenburg Metropolitan Region, Berlin-Brandenburg capital region has around 6.2 million inhabitants and is Metropolitan regions in Germany, Germany's third-largest metropolitan region after the Rhine-Ruhr and Frankfurt Rhine-Main, Rhine-Main regions. Berlin straddles the banks of the Spree (river), Spree, which flows into the Havel (a tributary of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Buchanan (Texas)
Lake Buchanan () was formed by the construction of Buchanan Dam by the Lower Colorado River Authority to provide a water supply for the region and to provide hydroelectric power. Buchanan Dam, a structure over 2 mi (3.2 km) in length, was completed in 1939. Lake Buchanan was the first of the Texas Highland Lakes to be formed, and with of surface water, it is also the largest. The surface of the lake includes area in both Burnet and Llano Counties. The lake is west of the city of Burnet, Texas. The other reservoirs on the Colorado River are Inks Lake, Lake LBJ, Lake Marble Falls, Lake Travis, Lake Austin, and Lady Bird Lake. The lake is named for Representative James P. Buchanan (1867–1937), who is credited with securing the funding to build the lake and dam. History Lake Buchanan was artificially created upon the completion of the adjacent Buchanan Dam in 1938. Work on the dam itself began in April 1931, but was suspended a year later. Work resumed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
