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C. J. Gorter
Cornelis Jacobus (Cor) Gorter (14 August 1907, Utrecht – 30 March 1980, Leiden) was a Dutch experimental and theoretical physicist. Among other work, he discovered paramagnetic relaxation and was a pioneer in low temperature physics. Education and career After his Abitur in The Hague, Gorter studied physics in Leiden, earning his PhD with the thesis ''Paramagnetische Eigenschaften von Salzen'' ("Paramagnetic Properties of Salts") under Wander de Haas. From 1931 to 1936 he worked at Teylers Stichting in Haarlem and from 1936 to 1940 at the University of Groningen, before he became a professor at the University of Amsterdam as successor to Pieter Zeeman. In 1946, succeeding W. H. Keesom, he returned to Leiden as a professor. In 1948, as successor to De Haas, Gorter directed the Kamerlingh Onnes Laboratory, remaining there until his retirement in 1973. He died in Leiden in 1980, after suffering for several years from Alzheimer's disease. His doctoral students include Nicolaas B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Utrecht
Utrecht ( , , ) is the fourth-largest city and a municipality of the Netherlands, capital and most populous city of the province of Utrecht. It is located in the eastern corner of the Randstad conurbation, in the very centre of mainland Netherlands, about 35 km south east of the capital Amsterdam and 45 km north east of Rotterdam. It has a population of 361,966 as of 1 December 2021. Utrecht's ancient city centre features many buildings and structures, several dating as far back as the High Middle Ages. It has been the religious centre of the Netherlands since the 8th century. It was the most important city in the Netherlands until the Dutch Golden Age, when it was surpassed by Amsterdam as the country's cultural centre and most populous city. Utrecht is home to Utrecht University, the largest university in the Netherlands, as well as several other institutions of higher education. Due to its central position within the country, it is an important hub for both rail and roa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hendrik Casimir
Hendrik Brugt Gerhard Casimir (15 July 1909 – 4 May 2000) was a Dutch physicist best known for his research on the two-fluid model of superconductors (together with C. J. Gorter) in 1934 and the Casimir effect (together with D. Polder) in 1948. Biography Casimir was born 15 July 1909. He studied theoretical physics at the University of Leiden under Paul Ehrenfest, where he received his Ph.D. in 1931. His Ph.D. thesis dealt with the quantum mechanics of a rigid spinning body and the group theory of the rotations of molecules. During that time he also spent some time in Copenhagen with Niels Bohr, where he helped Bohr support the latter's hypothesis of the " gunslinger effect" with mock shoot-outs on campus. From 1932 to mid-1933, Casimir worked as an assistant to Wolfgang Pauli at ETH Zurich. During this period, he worked on the relativistic theory of the electron, in particular, evaluating deviations of the Klein-Nishina equation in the case of bound electrons. To attack th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
National Academy Of Sciences
The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the National Academy of Medicine (NAM). As a national academy, new members of the organization are elected annually by current members, based on their distinguished and continuing achievements in original research. Election to the National Academy is one of the highest honors in the scientific field. Members of the National Academy of Sciences serve ''pro bono'' as "advisers to the nation" on science, engineering, and medicine. The group holds a congressional charter under Title 36 of the United States Code. Founded in 1863 as a result of an Act of Congress that was approved by Abraham Lincoln, the NAS is charged with "providing independent, objective advice to the nation on matters related to science and technology. ... to provide scien ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fritz London
Fritz Wolfgang London (March 7, 1900 – March 30, 1954) was a German physicist and professor at Duke University. His fundamental contributions to the theories of chemical bonding and of intermolecular forces ( London dispersion forces) are today considered classic and are discussed in standard textbooks of physical chemistry. With his brother Heinz London, he made a significant contribution to understanding electromagnetic properties of superconductors with the London equations and was nominated for the Nobel Prize in Chemistry on five separate occasions. Biography London was born in Breslau, Germany (now Wrocław, Poland) as the son of Franz London (1863-1917). Being a Jew, London lost his position at the University of Berlin after Hitler's Nazi Party passed the 1933 racial laws. He took visiting positions in England and France, and emigrated to the United States in 1939, of which he became a naturalized citizen in 1945. Later in his life, London was a professor at Duke Unive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Academy Of Arts And Sciences
The American Academy of Arts and Sciences (abbreviation: AAA&S) is one of the oldest learned societies in the United States. It was founded in 1780 during the American Revolution by John Adams, John Hancock, James Bowdoin, Andrew Oliver, and other Founding Fathers of the United States. It is headquartered in Cambridge, Massachusetts. Membership in the academy is achieved through a thorough petition, review, and election process. The academy's quarterly journal, '' Dædalus'', is published by MIT Press on behalf of the academy. The academy also conducts multidisciplinary public policy research. History The Academy was established by the Massachusetts legislature on May 4, 1780, charted in order "to cultivate every art and science which may tend to advance the interest, honor, dignity, and happiness of a free, independent, and virtuous people." The sixty-two incorporating fellows represented varying interests and high standing in the political, professional, and commercial ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Netherlands Academy Of Arts And Sciences
The Royal Netherlands Academy of Arts and Sciences ( nl, Koninklijke Nederlandse Akademie van Wetenschappen, abbreviated: KNAW) is an organization dedicated to the advancement of science and literature in the Netherlands. The academy is housed in the Trippenhuis in Amsterdam. In addition to various advisory and administrative functions it operates a number of research institutes and awards many prizes, including the Lorentz Medal in theoretical physics, the Dr Hendrik Muller Prize for Behavioural and Social Science and the Heineken Prizes. Main functions The academy advises the Dutch government on scientific matters. While its advice often pertains to genuine scientific concerns, it also counsels the government on such topics as policy on careers for researchers or the Netherlands' contribution to major international projects. The academy offers solicited and unsolicited advice to parliament, ministries, universities and research institutes, funding agencies and internatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coulomb Blockade
In mesoscopic physics, a Coulomb blockade (CB), named after Charles-Augustin de Coulomb's electrical force, is the decrease in electrical conductance at small bias voltages of a small electronic device comprising at least one low-capacitance tunnel junction. Because of the CB, the conductance of a device may not be constant at low bias voltages, but disappear for biases under a certain threshold, i.e. no current flows. Coulomb blockade can be observed by making a device very small, like a quantum dot. When the device is small enough, electrons inside the device will create a strong Coulomb repulsion preventing other electrons to flow. Thus, the device will no longer follow Ohm's law and the current-voltage relation of the Coulomb blockade looks like a staircase. Even though the Coulomb blockade can be used to demonstrate the quantization of the electric charge, it remains a classical effect and its main description does not require quantum mechanics. However, when few elect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Helium II
Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. Its boiling and melting point are the lowest among all the elements. It is the second lightest and second most abundant element in the observable universe (hydrogen is the lightest and most abundant). It is present at about 24% of the total elemental mass, which is more than 12 times the mass of all the heavier elements combined. Its abundance is similar to this in both the Sun and in Jupiter, due to the very high nuclear binding energy (per nucleon) of helium-4, with respect to the next three elements after helium. This helium-4 binding energy also accounts for why it is a product of both nuclear fusion and radioactive decay. The most common isotope of helium in the universe is helium-4, the vast majority of which was formed during the Big ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copper(II) Chloride
Copper(II) chloride is the chemical compound with the chemical formula CuCl2. The anhydrous form is yellowish brown but slowly absorbs moisture to form a blue-green dihydrate. Both the anhydrous and the dihydrate forms occur naturally as the very rare minerals tolbachite and eriochalcite, respectively.Marlene C. Morris, Howard F. McMurdie, Eloise H. Evans, Boris Paretzkin, Harry S. Parker, and Nicolas C. Panagiotopoulos (1981) ''Copper chloride hydrate (eriochalcite)'', in Standard X-ray Diffraction Powder PatternsNational Bureau of Standards, Monograph 25, Section 18; page 33. Structure Anhydrous CuCl2 adopts a distorted cadmium iodide structure. In this motif, the copper centers are octahedral. Most copper(II) compounds exhibit distortions from idealized octahedral geometry due to the Jahn-Teller effect, which in this case describes the localization of one d-electron into a molecular orbital that is strongly antibonding with respect to a pair of chloride ligands. In CuCl2· ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antiferromagnetism
In materials that exhibit antiferromagnetism, the magnetic moments of atoms or molecules, usually related to the spins of electrons, align in a regular pattern with neighboring spins (on different sublattices) pointing in opposite directions. This is, like ferromagnetism and ferrimagnetism, a manifestation of ordered magnetism. The phenomenon of antiferromagnetism was first introduced by Lev Landau in 1933. Generally, antiferromagnetic order may exist at sufficiently low temperatures, but vanishes at and above the Néel temperature – named after Louis Néel, who had first identified this type of magnetic ordering. Above the Néel temperature, the material is typically paramagnetic. Measurement When no external field is applied, the antiferromagnetic structure corresponds to a vanishing total magnetization. In an external magnetic field, a kind of ferrimagnetic behavior may be displayed in the antiferromagnetic phase, with the absolute value of one of the sublattice mag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Viscosity
The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water. Viscosity quantifies the internal frictional force between adjacent layers of fluid that are in relative motion. For instance, when a viscous fluid is forced through a tube, it flows more quickly near the tube's axis than near its walls. Experiments show that some stress (such as a pressure difference between the two ends of the tube) is needed to sustain the flow. This is because a force is required to overcome the friction between the layers of the fluid which are in relative motion. For a tube with a constant rate of flow, the strength of the compensating force is proportional to the fluid's viscosity. In general, viscosity depends on a fluid's state, such as its temperature, pressure, and rate of deformation. However, the dependence on some of these properties ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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