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John Kraus
John Daniel Kraus (June 28, 1910 – July 18, 2004) was an American physicist and electrical engineer known for his contributions to electromagnetics, radio astronomy, and antenna theory. His inventions included the helical antenna, the corner reflector antenna, and several other types of antennas. He designed the Big Ear radio telescope at Ohio State University, which was constructed mostly by a team of OSU students and was used to carry out the Ohio Sky Survey. Kraus held a number of patents and published widely. Personal Kraus was born in 1910 in Ann Arbor, Michigan. He received his Ph.D. in physics from the University of Michigan in 1933. In addition to his professional achievements, he was an amateur radio operator, license , and made many technical contributions to amateur radio, particularly his development of the close-spaced directional array. His father was scientist Edward Henry Kraus. Before World War II Kraus developed antennas including the corner ref ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ann Arbor, Michigan
Ann Arbor is a city in Washtenaw County, Michigan, United States, and its county seat. The 2020 United States census, 2020 census recorded its population to be 123,851, making it the List of municipalities in Michigan, fifth-most populous city in Michigan. Located on the Huron River, Ann Arbor is the principal city of its Metropolitan statistical area, metropolitan area, which encompasses all of Washtenaw County and had 372,258 residents in 2020. Ann Arbor is included in the Metro Detroit, Detroit–Warren–Ann Arbor combined statistical area and the Great Lakes megalopolis. Ann Arbor was founded in 1824 by John Allen (pioneer), John Allen and Elisha Rumsey. It was named after the wives of the village's founders, both named Ann, and the stands of Quercus macrocarpa, bur oak trees they found at the site of the town. The University of Michigan was established in Ann Arbor in 1837, and the city's population grew at a rapid rate in the early to mid-20th century. A college town, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ohio Sky Survey
The Ohio Sky Survey was an astronomical survey of extragalactic radio sources. Data were taken between 1965 and 1971 using the Big Ear radio telescope at the Ohio State University Radio Observatory (OSURO), also known as the "Big Ear Radio Observatory (BERO)". The survey covered 94% of the sky area between the limiting declinations of 63°N and 36°S with a resolution at 1415 MHz of 40 arc minutes in declination. The survey was carried out primarily at a frequency of 1415 MHz but observations were also made at 2650 MHz and 612 MHz. Roughly 19,620 sources were identified over the course of the survey of which 60% were previously uncatalogued. The survey was unique in that it covered a larger portion of the sky, to a greater depth, and at a higher frequency, than any previous survey. In addition, all previously catalogued sources were tabulated and maps of the areas surveyed were included with the positions of all catalogued sources. Sources discovered in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Radio Relay League
The American Radio Relay League (ARRL) is the largest membership association of amateur radio enthusiasts in the United States. ARRL is a non-profit organization and was co-founded on April 6, 1914, by Hiram Percy Maxim and Clarence D. Tuska of Hartford, Connecticut. The ARRL represents the interests of amateur radio operators before federal regulatory bodies, provides technical advice and assistance to amateur radio enthusiasts, supports a number of educational programs and sponsors emergency communications service throughout the country. The ARRL has approximately 161,000 members. In addition to members in the US, the organization claims over 7,000 members in other countries. The ARRL publishes many books and a monthly membership journal called '' QST''. The ARRL is the primary representative organization of amateur radio operators to the US government. It performs this function by lobbying the US Congress and the Federal Communications Commission. The ARRL is also the interna ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Countermeasure
A countermeasure is a measure or action taken to counter or offset another one. As a general concept, it implies precision and is any technological or tactical solution or system designed to prevent an undesirable outcome in the process. The first known use of the term according to the Merriam-Webster dictionary was in 1923. Countermeasures can refer to the following disciplinary spectrum: * Medicine * Materials engineering * Electro-magnetic engineering * Policing * Information technology * International Law * Diplomatic security * Pollution prevention * Aviation Defense countermeasures are often divided into "active" and "passive". Active "Active" countermeasures mean the system user or the defender takes an active position because the incoming incident is known so the system takes active approaches to deal with such possible damage. Such an approach may include setting up a security method for the incident or actively trying to stop or intersect such damage. Passive "Pass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Navy
The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful navy with the largest Displacement (ship), displacement, at 4.5 million tons in 2021. It has the world's largest aircraft carrier fleet, with List of aircraft carriers in service, eleven in service, one undergoing trials, two new carriers under construction, and six other carriers planned as of 2024. With 336,978 personnel on active duty and 101,583 in the Ready Reserve, the U.S. Navy is the third largest of the United States military service branches in terms of personnel. It has 299 deployable combat vessels and about 4,012 operational aircraft as of 18 July 2023. The U.S. Navy is one of six United States Armed Forces, armed forces of the United States and one of eight uniformed services of the United States. The United States Navy traces its origins to the Continental Navy, which was established during ... [...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] |
Cyclotron
A cyclotron is a type of particle accelerator invented by Ernest Lawrence in 1929–1930 at the University of California, Berkeley, and patented in 1932. Lawrence, Ernest O. ''Method and apparatus for the acceleration of ions'', filed: January 26, 1932, granted: February 20, 1934 A cyclotron accelerates charged particles outwards from the center of a flat cylindrical vacuum chamber along a spiral path. The particles are held to a spiral trajectory by a static magnetic field and accelerated by a rapidly varying electric field. Lawrence was awarded the 1939 Nobel Prize in Physics for this invention. The cyclotron was the first "cyclical" accelerator. The primary accelerators before the development of the cyclotron were electrostatic accelerators, such as the Cockcroft–Walton generator and the Van de Graaff generator. In these accelerators, particles would cross an accelerating electric field only once. Thus, the energy gained by the particles was limited by the maximum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Corner Reflector Antenna
A corner reflector antenna is a type of directional antenna used at VHF and UHF frequencies. It was invented by John D. Kraus in 1938.Kraus, John D., US patent 2270314 Corner reflector antenna filed January 31, 1940; granted January 20, 1942. It consists of a dipole driven element mounted in front of two flat rectangular reflecting screens joined at an angle, usually 90°. Corner reflector antennas have moderate gain of 10–15 dB, high front-to-back ratio of 20–30 dB, and wide bandwidth. Corner reflector antennas are widely used for UHF television receiving antennas, point-to-point communication links and data links for wireless WANs, and amateur radio antennas on the 144, 420, and 1296 MHz bands. They radiate linearly polarized radio waves and can be mounted for either horizontal or vertical polarization. The corner reflector ''antenna'' should not be confused with a '' corner reflector'', a passive device used to reflect radio waves back towa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edward Henry Kraus
Edward Henry Kraus (1875–1973) was a professor of mineralogy at the University of Michigan and also served as Dean of the Summer Session, 1915–1933, Dean of the College of Pharmacy, 1923–1933, and Dean of the College of Literature, Science and the Arts, 1933–1945. Biography Edward Henry Kraus was born at Syracuse, New York, on December 1, 1875. His father was John Erhardt Kraus, of German ancestry, and his mother, Rosa Kocher Kraus, was of Swiss descent. After training in the high school of Syracuse, he entered Syracuse University, from which he was graduated as Bachelor of Science in 1896. During the following year he was a graduate student in that university and was also an assistant in chemistry and German. He received the degree of Master of Science at the end of the year. For two years, 1897–1899, he was instructor in German and mineralogy at Syracuse. During 1899–1901 he studied at the University of Munich, and at the end of the period received the degree of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scientist
A scientist is a person who Scientific method, researches to advance knowledge in an Branches of science, area of the natural sciences. In classical antiquity, there was no real ancient analog of a modern scientist. Instead, philosophers engaged in the philosophical study of nature called natural philosophy, a precursor of natural science. Though Thales ( 624–545 BC) was arguably the first scientist for describing how cosmic events may be seen as natural, not necessarily caused by gods,Frank N. Magill''The Ancient World: Dictionary of World Biography'', Volume 1 Routledge, 2003 it was not until the 19th century in science, 19th century that the term ''scientist'' came into regular use after it was coined by the theologian, philosopher, and historian of science William Whewell in 1833. History The roles of "scientists", and their predecessors before the emergence of modern scientific disciplines, have evolved considerably over time. Scientists of different er ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Father
A father is the male parent of a child. Besides the paternal bonds of a father to his children, the father may have a parental, legal, and social relationship with the child that carries with it certain rights and obligations. A biological father is the male genetic contributor to the creation of the infant, through sexual intercourse or sperm donation. A biological father may have legal obligations to a child not raised by him, such as an obligation of monetary support. An adoptive father is a man who has become the child's parent through the legal process of adoption. A putative father is a man whose biological relationship to a child is alleged but has not been established. A stepfather is a non-biological male parent married to a child's preexisting parent and may form a family unit but generally does not have the legal rights and responsibilities of a parent in relation to the child. The adjective "paternal" refers to a father and comparatively to "maternal" for a mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amateur Radio
Amateur radio, also known as ham radio, is the use of the radio frequency radio spectrum, spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emergency, emergency communications. The term ''"radio amateur"'' is used to specify ''"a duly authorized person interested in radioelectric practice with a purely personal aim and without wikt:pecuniary, pecuniary interest"'' (either direct monetary or other similar reward); and to differentiate it from commercial broadcasting, public safety (police and fire), or two-way radio professional services (maritime, aviation, taxis, etc.). The amateur radio service (''amateur service'' and ''amateur-satellite service'') is established by the International Telecommunication Union (ITU) through their recommended radio regulations. National governments regulate technical and operational characteristics of transmissions and issue individual station li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
