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Image Dissector
An image dissector, also called a dissector tube, is a video camera tube in which photocathode emissions create an "electron image" which is then swept up, down and across an anode to produce an electrical signal representing the visual image. It employs magnetic fields to keep the electron image in focus, and later models used electron multiplier to pick up the electrons.Horowitz, Paul and Winfield Hill, ''The Art of Electronics'', Second Edition Cambridge University Press, 1989, pp. 1000-1001. . The term had also been used for other kinds of early video camera tubes. Dissectors were used only briefly in television systems before being replaced by the much more s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Farnsworth Image Dissector Tube
Farnsworth may refer to: Places *Farnsworth, Indiana, a ghost town *Farnsworth, Texas, an unincorporated community in the Texas Panhandle *Farnsworth Peak, a mountain located west of Salt Lake City, Utah People *Farnsworth (surname), a list of people and fictional characters *Donald Farnsworth, Farnsworth Donald (1952), American artist, inventor, papermaker *Farnsworth Wright (1888–1940), editor of the pulp magazine ''Weird Tales'' Other uses *Farnsworth Art Museum, Rockland, Maine *Farnsworth House (other), various places *Farnsworth Lantern Test, used to screen for color blindness *Farnsworth Middle School, Guilderland Central School District, Guilderland, New York *Farnsworth Metropark, near Toledo, Ohio *Farnsworth method of learning Morse code *Farnsworth, a diesel engine in the 1991 movie ''The Little Engine That Could (1991 film), The Little Engine that Could'' See also *Gen. Charles S. Farnsworth County Park, located in Altadena, California * Farnworth (dis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reduction To Practice
In United States patent law, the reduction to practice is the step in the formation of an invention beyond the conception thereof. Reduction to practice may be either actual (the invention is actually carried out and is found to work for its intended purpose) or constructive (a patent application having a sufficient disclosure is filed). The date of reduction to practice was critical to the determination of priority between inventors in an interference proceeding under the discontinued first-to-invent system as well as for swearing behind a reference under that system. Conception is the "formation in the mind of the inventor, of a definite and permanent idea of the complete and operative invention, as it is hereafter to be applied in practice." ''Hybritech Inc. v. Monoclonal Antibodies, Inc.'', 802 F.2d 1367, 1376 ( Fed. Cir. 1986) (quoting 1 Robinson ''On Patents'' 532 (1890). The reduction to practice of an invention can either be: * Actual reduction to practice: " quires tha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philadelphia, Pennsylvania
Philadelphia, often called Philly, is the largest city in the Commonwealth of Pennsylvania, the sixth-largest city in the U.S., the second-largest city in both the Northeast megalopolis and Mid-Atlantic regions after New York City. Since 1854, the city has been coextensive with Philadelphia County, the most populous county in Pennsylvania and the urban core of the Delaware Valley, the nation's seventh-largest and one of world's largest metropolitan regions, with 6.245 million residents . The city's population at the 2020 census was 1,603,797, and over 56 million people live within of Philadelphia. Philadelphia was founded in 1682 by William Penn, an English Quaker. The city served as capital of the Pennsylvania Colony during the British colonial era and went on to play a historic and vital role as the central meeting place for the nation's founding fathers whose plans and actions in Philadelphia ultimately inspired the American Revolution and the nation's inde ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Franklin Institute
The Franklin Institute is a science museum and the center of science education and research in Philadelphia, Pennsylvania. It is named after the American scientist and statesman Benjamin Franklin. It houses the Benjamin Franklin National Memorial. Founded in 1824, the Franklin Institute is one of the oldest centers of science education and development in the United States. Its chief astronomer is Derrick Pitts. History On February 5, 1824, Samuel Vaughan Merrick and William H. Keating founded the Franklin Institute of the State of Pennsylvania for the Promotion of the Mechanic Arts. Begun in 1825, the institute was an important force in the professionalization of American science and technology through the nineteenth century, beginning with early investigations into steam engines and water power. In addition to conducting scientific inquiry, it fostered research and education by running schools, publishing the influential ''Journal of The Franklin Institute'', sponsoring e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multipactor
The multipactor effect is a phenomenon in radio-frequency (RF) amplifier vacuum tubes and waveguides, where, under certain conditions, secondary electron emission in resonance with an alternating electric field leads to exponential electron multiplication, possibly damaging and even destroying the RF device. Description The multipactor effect occurs when electrons accelerated by radio-frequency (RF) fields are self-sustained in a vacuum (or near vacuum) via an electron avalanche caused by secondary electron emission. The impact of an electron to a surface can, depending on its energy and angle, release one or more secondary electrons into the vacuum. These electrons can then be accelerated by the RF fields and impact with the same or another surface. Should the impact energies, number of electrons released, and timing of the impacts be such that a sustained multiplication of the number of electrons occurs, the phenomenon can grow exponentially and may lead to operational problems ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
San Francisco
San Francisco (; Spanish language, Spanish for "Francis of Assisi, Saint Francis"), officially the City and County of San Francisco, is the commercial, financial, and cultural center of Northern California. The city proper is the List of California cities by population, fourth most populous in California and List of United States cities by population, 17th most populous in the United States, with 815,201 residents as of 2021. It covers a land area of , at the end of the San Francisco Peninsula, making it the second most densely populated large U.S. city after New York City, and the County statistics of the United States, fifth most densely populated U.S. county, behind only four of the five New York City boroughs. Among the 91 U.S. cities proper with over 250,000 residents, San Francisco was ranked first by per capita income (at $160,749) and sixth by aggregate income as of 2021. Colloquial nicknames for San Francisco include ''SF'', ''San Fran'', ''The '', ''Frisco'', and '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philo T
Philo of Alexandria (; grc, Φίλων, Phílōn; he, יְדִידְיָה, Yəḏīḏyāh (Jedediah); ), also called Philo Judaeus, was a Hellenistic Jewish philosopher who lived in Alexandria, in the Roman province of Egypt. Philo's deployment of allegory to harmonize Jewish scripture, mainly the Torah, with Greek philosophy was the first documented of its kind, and thereby often misunderstood. Many critics of Philo assumed his allegorical perspective would lend credibility to the notion of legend over historicity. Philo often advocated a literal understanding of the Torah and the historicity of such described events, while at other times favoring allegorical readings. Though never properly attributed, Philo's marriage of Jewish exegesis and Stoic philosophy provided a formula later picked up by other Midrash content from the 3rd and 4th centuries. Some claimed this lack of credit or affinity for Philo by the Rabbinic leadership at the time, was due to his adoption of alle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Television
Television, sometimes shortened to TV, is a telecommunication medium for transmitting moving images and sound. The term can refer to a television set, or the medium of television transmission. Television is a mass medium for advertising, entertainment, news, and sports. Television became available in crude experimental forms in the late 1920s, but only after several years of further development was the new technology marketed to consumers. After World War II, an improved form of black-and-white television broadcasting became popular in the United Kingdom and the United States, and television sets became commonplace in homes, businesses, and institutions. During the 1950s, television was the primary medium for influencing public opinion.Diggs-Brown, Barbara (2011''Strategic Public Relations: Audience Focused Practice''p. 48 In the mid-1960s, color broadcasting was introduced in the U.S. and most other developed countries. The availability of various types of archival st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Science Museum, London
The Science Museum is a major museum on Exhibition Road in South Kensington, London. It was founded in 1857 and is one of the city's major tourist attractions, attracting 3.3 million visitors annually in 2019. Like other publicly funded national museums in the United Kingdom, the Science Museum does not charge visitors for admission, although visitors are requested to make a donation if they are able. Temporary exhibitions may incur an admission fee. It is one of the five museums in the Science Museum Group. Founding and history The museum was founded in 1857 under Bennet Woodcroft from the collection of the Royal Society of Arts and surplus items from the Great Exhibition as part of the South Kensington Museum, together with what is now the Victoria and Albert Museum. It included a collection of machinery which became the ''Museum of Patents'' in 1858, and the ''Patent Office Museum'' in 1863. This collection contained many of the most famous exhibits of what is now t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Institute Of Electrical Engineers
The Institution of Electrical Engineers (IEE) was a British professional organisation of electronics, electrical, manufacturing, and Information Technology professionals, especially electrical engineers. It began in 1871 as the Society of Telegraph Engineers. In 2006, it changed its name to the Institution of Engineering and Technology (IET). Notable past presidents have included Lord Kelvin (1889), Sir Joseph Swan (1898) and Sebastian de Ferranti (1910–11). Notable chairmen include John M. M. Munro (1910–11). History The IEE was founded in 1871 as the Society of Telegraph Engineers, changed its name in 1880 to the Society of Telegraph Engineers and Electricians and changed to the Institution of Electrical Engineers in 1888. It was Incorporated by a Royal Charter in 1921. In 1988 the Institution of Electrical Engineers (IEE) merged with the Institution of Electronic and Radio Engineers (IERE), originally the British Institution of Radio Engineers (Brit IRE) founded i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Field (physics)
In physics, a field is a physical quantity, represented by a scalar (mathematics), scalar, vector (mathematics and physics), vector, or tensor, that has a value for each Point (geometry), point in Spacetime, space and time. For example, on a weather map, the surface temperature is described by assigning a real number, number to each point on the map; the temperature can be considered at a certain point in time or over some interval of time, to study the dynamics of temperature change. A surface wind map, assigning an vector (mathematics and physics), arrow to each point on a map that describes the wind velocity, speed and direction at that point, is an example of a vector field, i.e. a 1-dimensional (rank-1) tensor field. Field theories, mathematical descriptions of how field values change in space and time, are ubiquitous in physics. For instance, the electric field is another rank-1 tensor field, while electrodynamics can be formulated in terms of Mathematical descriptions of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Field
An electric field (sometimes E-field) is the physical field that surrounds electrically charged particles and exerts force on all other charged particles in the field, either attracting or repelling them. It also refers to the physical field for a system of charged particles. Electric fields originate from electric charges and time-varying electric currents. Electric fields and magnetic fields are both manifestations of the electromagnetic field, one of the four fundamental interactions (also called forces) of nature. Electric fields are important in many areas of physics, and are exploited in electrical technology. In atomic physics and chemistry, for instance, the electric field is the attractive force holding the atomic nucleus and electrons together in atoms. It is also the force responsible for chemical bonding between atoms that result in molecules. The electric field is defined as a vector field that associates to each point in space the electrostatic ( Coulomb) for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
