|
Charles H. Papas
Charles Herach Papas (March 29, 1918 – July 8, 2007) was an American applied physicist and electrical engineer, known for his contributions to electromagnetic theory, microwaves, radiophysics, gravitational electromagnetics, astrophysics, guided waves, and remote sensing. His book ''Theory of Electromagnetic Wave Propagation'' is a recognized classic on electromagnetic theory. Background Charles Herach Papas was born on March 29, 1918, in Troy, New York. Following his family, which was involved in the import/export trade, he spent his early childhood in Tianjin, China. After returning to the United States and completing high school, he matriculated at the Massachusetts Institute of Technology where he received a B.S. in electrical engineering in 1941. He completed his graduate studies at Harvard University, where he obtained an M.S. in communications engineering in 1946 and a PhD in electrodynamics in 1948, with a dissertation titled ''A Theoretical Investigation of Spheric ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Troy, NY
Troy is a city in and the county seat of Rensselaer County, New York, United States. It is located on the western edge of the county, on the eastern bank of the Hudson River just northeast of the capital city of Albany. At the 2020 census, the population of Troy was 51,401. Troy has close ties to Albany and nearby Schenectady, forming a region called the Capital District, which has a population of 1.24 million. The area long had been occupied by the Mohican Indian tribe, but Dutch settlement began in the mid-17th century. The Dutch colony was conquered by the English in 1664, renamed Troy in 1789 and was incorporated as a town in 1791. Due to the confluence of major waterways and a geography that supported water power, the American Industrial Revolution took hold in this area, making Troy reputedly the fourth-wealthiest city in America around the turn of the 20th century. As a result, Troy is noted for its Victorian architecture. Troy is home to a number of institutions of high ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guided Waves
A waveguide is a structure that guides waves by restricting the transmission of energy to one direction. Common types of waveguides include acoustic waveguides which direct sound, optical waveguides which direct light, and radio-frequency waveguides which direct electromagnetic waves other than light like radio waves. Without the physical constraint of a waveguide, waves would expand into three-dimensional space and their intensities would decrease according to the inverse square law. There are different types of waveguides for different types of waves. The original and most common meaning is a hollow conductive metal pipe used to carry high frequency radio waves, particularly microwaves. Dielectric waveguides are used at higher radio frequencies, and transparent dielectric waveguides and optical fibers serve as waveguides for light. In acoustics, air ducts and horns are used as waveguides for sound in musical instruments and loudspeakers, and specially-shaped metal rods c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Léon Brillouin
Léon Nicolas Brillouin (; August 7, 1889 – October 4, 1969) was a French physicist. He made contributions to quantum mechanics, radio wave propagation in the atmosphere, solid-state physics, and information theory. Early life Brillouin was born in Sèvres, near Paris, France. His father, Marcel Brillouin, grandfather, Éleuthère Mascart, and great-grandfather, Charles Briot, were physicists as well. Education From 1908 to 1912, Brillouin studied physics at the École Normale Supérieure, in Paris. From 1911 he studied under Jean Perrin until he left for the Ludwig Maximilian University of Munich (LMU), in 1912. At LMU, he studied theoretical physics with Arnold Sommerfeld. Just a few months before Brillouin's arrival at LMU, Max von Laue had conducted his experiment showing X-ray diffraction in a crystal lattice. In 1913, he went back to France to study at the University of Paris and it was in this year that Niels Bohr submitted his first paper on the Bohr model of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antenna (radio)
In radio-frequency engineering, an antenna (American English) or aerial (British English) is an electronic device that converts an alternating current, alternating electric current into radio waves (transmitting), or radio waves into an electric current (receiving). It is the interface between radio waves Radio propagation, propagating through space and electric currents moving in metal Electrical conductor, conductors, used with a transmitter or receiver (radio), receiver. In transmission (telecommunications), transmission, a radio transmitter supplies an electric current to the antenna's Terminal (electronics), terminals, and the antenna radiates the energy from the current as electromagnetic radiation, electromagnetic waves (radio waves). In receiver (radio), reception, an antenna intercepts some of the power of a radio wave in order to produce an electric current at its terminals, that is applied to a receiver to be amplifier, amplified. Antennas are essential components ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radar
Radar is a system that uses radio waves to determine the distance ('' ranging''), direction ( azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track aircraft, ships, spacecraft, guided missiles, motor vehicles, map weather formations, and terrain. The term ''RADAR'' was coined in 1940 by the United States Navy as an acronym for "radio detection and ranging". The term ''radar'' has since entered English and other languages as an anacronym, a common noun, losing all capitalization. A radar system consists of a transmitter producing electromagnetic waves in the radio or microwave domain, a transmitting antenna, a receiving antenna (often the same antenna is used for transmitting and receiving) and a receiver and processor to determine properties of the objects. Radio waves (pulsed or continuous) from the transmitter reflect off the objects and return to the receiver, giving ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bureau Of Ships
The United States Navy's Bureau of Ships (BuShips) was established by Congress on 20 June 1940, by a law which consolidated the functions of the Bureau of Construction and Repair (BuC&R) and the Bureau of Engineering (BuEng). The new bureau was to be headed by a chief and deputy-chief, one selected from the Engineering Corps (Marine Engineer) and the other from the Construction Corps (Naval Architect). The chief of the former Bureau of Engineering, Rear Admiral Samuel M. "Mike" Robinson, was named BuShips' first chief, while the former chief of the Bureau of Construction & Repair, Rear Admiral Alexander H. Van Keuren, was named as BuShips' first Deputy-Chief. The bureau's responsibilities included supervising the design, construction, conversion, procurement, maintenance, and repair of ships and other craft for the Navy; managing shipyards, repair facilities, laboratories, and shore stations; developing specifications for fuels and lubricants; and conducting salvage operations. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Degaussing
Degaussing, or deperming, is the process of decreasing or eliminating a remnant magnetic field. It is named after the gauss, a unit of magnetism, which in turn was named after Carl Friedrich Gauss. Due to magnetic hysteresis, it is generally not possible to reduce a magnetic field completely to zero, so degaussing typically induces a very small "known" field referred to as bias. Degaussing was originally applied to reduce ships' magnetic signatures during World War II. Degaussing is also used to reduce magnetic fields in tape recorders and cathode-ray tube displays, and to destroy data held on magnetic storage. Ships' hulls The term was first used by then-Commander Charles F. Goodeve, Royal Canadian Naval Volunteer Reserve, during World War II while trying to counter the German magnetic naval mines that were wreaking havoc on the British fleet. The mines detected the increase in the magnetic field when the steel in a ship concentrated the Earth's magnetic field over it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naval Ordnance Laboratory
The Naval Ordnance Laboratory (NOL) was a facility in the White Oak, Maryland, White Oak area of Montgomery County, Maryland. The location is now used as the headquarters of the Food and Drug Administration, U.S. Food and Drug Administration. Origins The U.S. Navy Mine Unit, later the Mine Laboratory at the Washington, D.C., Navy Yard, was established in 1918, and the first Officer in Charge (OIC) arrived in February 1919, marking the beginning of the Laboratory. In 1929 the Mine Laboratory was merged with the Experimental Ammunition Station in Indian Head, Maryland, Indian Head to form the Naval Ordnance Laboratory. NOL began slowly, and it was not until the beginnings of World War II, when Germany's aircraft-laid magnetic mine began to cause serious problems for the Allies of World War II, Allies. As the importance of NOL's work became apparent, it also became apparent that there wasn't enough space at the Navy Yard to accommodate the necessary research facilities. In 1944, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Washington, DC
Washington, D.C., formally the District of Columbia and commonly known as Washington or D.C., is the capital city and Federal district of the United States, federal district of the United States. The city is on the Potomac River, across from Virginia, and shares land borders with Maryland to its north and east. It was named after George Washington, the first president of the United States. The district is named for Columbia (personification), Columbia, the female National personification, personification of the nation. The Constitution of the United States, U.S. Constitution in 1789 called for the creation of a federal district under District of Columbia home rule, exclusive jurisdiction of the United States Congress, U.S. Congress. As such, Washington, D.C., is not part of any U.S. state, state, and is not one itself. The Residence Act, adopted on July 16, 1790, approved the creation of the Capital districts and territories, capital district along the Potomac River. The city ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Department Of The Navy
The United States Department of the Navy (DON) is one of the three military departments within the United States Department of Defense. It was established by an Act of Congress on 30 April 1798, at the urging of Secretary of War James McHenry, to provide a government organizational structure to the United States Navy (USN).Bernard C. Steiner and James McHenry, The life and correspondence of James McHenry' (Cleveland: Burrows Brothers Co., 1907). Since 1834, the department has exercised jurisdiction over the United States Marine Corps (USMC), and during wartime the United States Coast Guard (USCG). These branches remain at all times independent and coequal service branches within the DON. It is led by the secretary of the Navy (SECNAV), a statutory civilian officer. The Department of the Navy was an executive department, whose secretary served on the president's cabinet, until 1949, when amendments to the National Security Act of 1947 established the Department of Defe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caltech
The California Institute of Technology (branded as Caltech) is a private university, private research university in Pasadena, California, United States. The university is responsible for many modern scientific advancements and is among a small group of Institute of Technology (United States), institutes of technology in the United States that are devoted to the instruction of pure and applied sciences. The institution was founded as a preparatory and vocational school by Amos G. Throop in 1891 and began attracting influential scientists such as George Ellery Hale, Arthur Amos Noyes, and Robert Andrews Millikan in the early 20th century. The vocational and preparatory schools were disbanded and spun off in 1910, and the college assumed its present name in 1920. In 1934, Caltech was elected to the Association of American Universities, and the antecedents of NASA's Jet Propulsion Laboratory, which Caltech continues to manage and operate, were established between 1936 and 1943 under ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tianjin
Tianjin is a direct-administered municipality in North China, northern China on the shore of the Bohai Sea. It is one of the National Central City, nine national central cities, with a total population of 13,866,009 inhabitants at the time of the 2020 Chinese census. Its metropolitan area, which is made up of 12 central districts (other than Baodi District, Baodi, Jizhou District, Tianjin, Jizhou, Jinghai District, Jinghai and Ninghe District, Ninghe), was home to 11,165,706 inhabitants and is also the world's 29th-largest agglomeration (between Chengdu and Rio de Janeiro) and 11th-List of cities proper by population, most populous city proper. Tianjin is governed as one of the four municipalities (alongside Beijing, Shanghai, and Chongqing) under the direct-administered municipalities of China, direct administration of the State Council of the People's Republic of China, State Council of Government of China, China. The city borders Hebei Province and Beijing Municipality, bounded ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
