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Alexander Popov (physicist)
Alexander Stepanovich Popov (sometimes spelled Popoff; russian: Алекса́ндр Степа́нович Попо́в; – ) was a Russian physicist, who was one of the first persons to invent a radio receiving device. declassified 8 January 2008 Popov's work as a teacher at a Russian naval school led him to explore high frequency electrical phenomena. On 7 May 1895, he presented a paper on a wireless lightning detector he had built that worked via using a coherer to detect radio noise from lightning strikes. This day is celebrated in the Russian Federation as Radio Day. In a 24 March 1896 demonstration, he transmitted radio signals 250 meters between different campus buildings in St. Petersburg. His work was based on that of another physicist – Oliver Lodge, and contemporaneous with the work of Guglielmo Marconi. Early life Born in the town of Krasnoturinsk, Sverdlovsk Oblast in the Urals as the son of a priest, he became interested in natural sciences when he was a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perm Governorate
Perm Governorate (russian: link=no, Пермская губерния) was an administrative unit of the Russian Empire and the Soviet Union from 1781 to 1923. It was also known as the ''government of Perm''. It was located on both slopes of the Ural Mountains, and its administrative center was the city of Perm. The region gave its name to the Permian period. History On November 20 (December 1), 1780, Catherine II signed a decree establishing the governorship of Perm in the two regions – Perm and Yekaterinburg, and the establishment of the provincial city of Perm. The first Governor-General of Perm and Tobol regions was appointed Lieutenant-General Yevgeny Petrovich Kashkin. In accordance with the decree of Emperor Paul I of December 12, 1796 "A new division of the state in the province", Perm and Tobolsk governor-generalship was divided in Perm and Tobolsk Governorates. On July 15, 1919, from the Perm province has been allocated Yekaterinburg Governorate, consisting of 6 u ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Urals
The Ural Mountains ( ; rus, Ура́льские го́ры, r=Uralskiye gory, p=ʊˈralʲskʲɪjə ˈɡorɨ; ba, Урал тауҙары) or simply the Urals, are a mountain range that runs approximately from north to south through European Russia, western Russia, from the coast of the Arctic Ocean to the river Ural (river), Ural and northwestern Kazakhstan.Ural Mountains Encyclopædia Britannica on-line The mountain range forms part of the Boundaries between the continents of Earth, conventional boundary between the regions of Europe and Asia. Vaygach Island and the islands of Novaya Zemlya form a further continuation of the chain to the north into the Arctic Ocean. The Ural Mountains are one of the richest mineral regions in the world, containing more than 1,000 varieties of valuable minerals. The mountains lie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mirror Galvanometer
A mirror galvanometer is an ammeter that indicates it has sensed an electric current by deflecting a light beam with a mirror. The beam of light projected on a scale acts as a long massless pointer. In 1826, Johann Christian Poggendorff developed the mirror galvanometer for detecting electric currents. The apparatus is also known as a ''spot galvanometer'' after the spot of light produced in some models. Mirror galvanometers were used extensively in scientific instruments before reliable, stable electronic amplifiers were available. The most common uses were as recording equipment for seismometers and submarine cables used for telegraphy. In modern times, the term ''mirror galvanometer'' is also used for devices that move laser beams by rotating a mirror through a galvanometer set-up, often with a servo-like control loop. The name is often abbreviated as ''galvo''. Kelvin's galvanometer The mirror galvanometer was improved significantly by William Thomson, later to beco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MIT Press
The MIT Press is a university press affiliated with the Massachusetts Institute of Technology (MIT) in Cambridge, Massachusetts (United States). It was established in 1962. History The MIT Press traces its origins back to 1926 when MIT published under its own name a lecture series entitled ''Problems of Atomic Dynamics'' given by the visiting German physicist and later Nobel Prize winner, Max Born. Six years later, MIT's publishing operations were first formally instituted by the creation of an imprint called Technology Press in 1932. This imprint was founded by James R. Killian, Jr., at the time editor of MIT's alumni magazine and later to become MIT president. Technology Press published eight titles independently, then in 1937 entered into an arrangement with John Wiley & Sons in which Wiley took over marketing and editorial responsibilities. In 1962 the association with Wiley came to an end after a further 125 titles had been published. The press acquired its modern name af ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heinrich Hertz
Heinrich Rudolf Hertz ( ; ; 22 February 1857 – 1 January 1894) was a German physicist who first conclusively proved the existence of the electromagnetic waves predicted by James Clerk Maxwell's Maxwell's equations, equations of electromagnetism. The unit of frequency, cycle per second, was named the "hertz" in his honor.IEC History . Iec.ch. Biography Heinrich Rudolf Hertz was born in 1857 in Hamburg, then a sovereign state of the German Confederation, into a prosperous and cultured Hanseatic (class), Hanseatic family. His father was Gustav Ferdinand Hertz. His mother was Anna Elisabeth Pfefferkorn. While studying at the Gelehrtenschule des Johanneums in Hamburg, Hertz showed an aptitude for sciences as well as languages, learning Arabic. He studied sciences and engineering in th ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territories, nine Minor Outlying Islands, and 326 Indian reservations. The United States is also in free association with three Pacific Island sovereign states: the Federated States of Micronesia, the Marshall Islands, and the Republic of Palau. It is the world's third-largest country by both land and total area. It shares land borders with Canada to its north and with Mexico to its south and has maritime borders with the Bahamas, Cuba, Russia, and other nations. With a population of over 333 million, it is the most populous country in the Americas and the third most populous in the world. The national capital of the United States is Washington, D.C. and its most populous city and principal financial center is New York City. Paleo-Americ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World's Columbian Exposition
The World's Columbian Exposition (also known as the Chicago World's Fair) was a world's fair held in Chicago (''City in a Garden''); I Will , image_map = , map_caption = Interactive Map of Chicago , coordinates = , coordinates_footnotes = , subdivision_type = Country , subdivision_name ... in 1893 to celebrate the 400th anniversary of Christopher Columbus's arrival in the New World in 1492. The centerpiece of the Fair, held in Jackson Park (Chicago), Jackson Park, was a large water pool representing the voyage Columbus took to the New World. Chicago had won the right to host the fair over several other cities, including New York City, Washington, D.C., and St. Louis. The exposition was an influential social and cultural event and had a profound effect on American Architecture of the United States, architecture, the arts, American industrial optimism, and Chicago's image. The layout of the Chicago Columbian E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radio Waves
Radio waves are a type of electromagnetic radiation with the longest wavelengths in the electromagnetic spectrum, typically with frequencies of 300 gigahertz (GHz) and below. At 300 GHz, the corresponding wavelength is 1 mm (shorter than a grain of rice); at 30 Hz the corresponding wavelength is (longer than the radius of the Earth). Like all electromagnetic waves, radio waves in a vacuum travel at the speed of light, and in the Earth's atmosphere at a close, but slightly lower speed. Radio waves are generated by charged particles undergoing acceleration, such as time-varying electric currents. Naturally occurring radio waves are emitted by lightning and astronomical objects, and are part of the blackbody radiation emitted by all warm objects. Radio waves are generated artificially by an electronic device called a transmitter, which is connected to an antenna which radiates the waves. They are received by another antenna connected to a radio receiver, which p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oscillation
Oscillation is the repetitive or periodic variation, typically in time, of some measure about a central value (often a point of equilibrium) or between two or more different states. Familiar examples of oscillation include a swinging pendulum and alternating current. Oscillations can be used in physics to approximate complex interactions, such as those between atoms. Oscillations occur not only in mechanical systems but also in dynamic systems in virtually every area of science: for example the beating of the human heart (for circulation), business cycles in economics, predator–prey population cycles in ecology, geothermal geysers in geology, vibration of strings in guitar and other string instruments, periodic firing of nerve cells in the brain, and the periodic swelling of Cepheid variable stars in astronomy. The term ''vibration'' is precisely used to describe a mechanical oscillation. Oscillation, especially rapid oscillation, may be an undesirable phenomenon in proc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Resonance
Electrical resonance occurs in an electric circuit at a particular '' resonant frequency'' when the impedances or admittances of circuit elements cancel each other. In some circuits, this happens when the impedance between the input and output of the circuit is almost zero and the transfer function is close to one. Resonant circuits exhibit ringing and can generate higher voltages or currents than are fed into them. They are widely used in wireless (radio) transmission for both transmission and reception. LC circuits Resonance of a circuit involving capacitors and inductors occurs because the collapsing magnetic field of the inductor generates an electric current in its windings that charges the capacitor, and then the discharging capacitor provides an electric current that builds the magnetic field in the inductor. This process is repeated continually. An analogy is a mechanical pendulum, and both are a form of simple harmonic oscillator. At resonance, the series impedance of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kotlin Island
Kotlin (russian: Ко́тлин) ( sv, Reitskär) is a Russian island, located near the head of the Gulf of Finland, west of Saint Petersburg in the Baltic Sea. Kotlin separates the Neva Bay from the rest of the gulf. The fortified city of Kronstadt is located on the island and forms part of a World Heritage Site that is ''Saint Petersburg and Related Groups of Monuments''. The island serves as a gateway to Saint Petersburg and as such has been the site of several military engagements. The Kotlin programming language is named for the island, much as the Java programming language shares its name with an Indonesian island. History The city of Kronstadt was founded on Kotlin island by Peter the Great, who took it from the Swedes in 1703. In March 1921, Kotlin was the site of the Kronstadt rebellion, which resulted in over 11,000 casualties. Geography In general outline, the island forms an elongated triangle; long by about broad, with its base towards St Petersburg. The easter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
