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Aimé Cotton
Aimé Auguste Cotton (9 October 1869 – 16 April 1951) was a French physicist known for his studies of the interaction of light with chiral molecules. In the absorption bands of these molecules, he discovered large values of optical rotatory dispersion (ORD), or variation of optical rotation as a function of wavelength ( Cotton effect), as well as circular dichroism or differences of absorption between left and right circularly polarized light. Biography Aimé Cotton was born in Bourg-en-Bresse, Ain on 9 October 1869. His grandfather was director of the École normale (teachers' college) of Bourg, and his father, Eugène Cotton, was a mathematics professor at the college of Bourg, the institution where physicist André-Marie Ampère began his career. Aimé's brother Émile Cotton was a mathematician and academician. Aimé Cotton attended a lycée (high school) in Bourg and then the special mathematics program at the Lycée Blaise Pascal in Clermont-Ferrand. He entered ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bourg-en-Bresse
Bourg-en-Bresse (; frp, Bôrg) is the Prefectures in France, prefecture of the Ain Departments of France, department in the Auvergne-Rhône-Alpes Regions of France, region in Eastern France. Located northeast of Lyon, it is the capital of the ancient Provinces of France, province of Bresse ( frp, Brêsse, links=no). In 2018, the Communes of France, commune had a population of 41,248. Geography Bourg-en-Bresse is located at the western base of the Jura Mountains, on the left bank of the Reyssouze (river), Reyssouze, a tributary of the Saône. It lies northeast of Lyon and south-southwest of Lons-le-Saunier. History Roman remains have been discovered at Bourg, but little is known of its early history. It was probably pillaged by Goths in Late Antiquity. Raised to the rank of a free town in 1250, it was at the beginning of the 15th century the capital of the dukes of Duchy of Savoy, Savoy in the province of Bresse. In February 1535 it was conquered by France during a full-scale ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chirality (chemistry)
In chemistry, a molecule or ion is called chiral () if it cannot be superposed on its mirror image by any combination of rotation (geometry), rotations, translation (geometry), translations, and some Conformational isomerism, conformational changes. This geometric property is called chirality (). The terms are derived from Ancient Greek χείρ (''cheir'') 'hand'; which is the canonical example of an object with this property. A chiral molecule or ion exists in two stereoisomers that are mirror images of each other, called enantiomers; they are often distinguished as either "right-handed" or "left-handed" by their absolute configuration or some other criterion. The two enantiomers have the same chemical properties, except when reacting with other chiral compounds. They also have the same physics, physical properties, except that they often have opposite optical activity, optical activities. A homogeneous mixture of the two enantiomers in equal parts is said to be racemic mixtu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delegates To The Fourth Conference International Union For Cooperation In Solar Research At Mount Wilson Observatory
Delegate or delegates may refer to: * Delegate, New South Wales, a town in Australia * Delegate (CLI), a computer programming technique * Delegate (American politics), a representative in any of various political organizations * Delegate (United States Congress), a non-voting member of the United States House of Representatives * Delegate Apostolic or nuncio, an ecclesiastical diplomat representing the Holy See * The Delegates The Delegates were a novelty song group who scored a hit record, "Convention '72". Creation The Delegates were the creation of Bob DeCarlo, morning disc jockey at KQV in Pittsburgh. Bob was approached by local record moguls Nick Cenci and Nick Kou ..., a 1970s novelty song group See also * Delegation (other) {{Disambiguation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron
The electron ( or ) is a subatomic particle with a negative one elementary electric charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no known components or substructure. The electron's mass is approximately 1/1836 that of the proton. Quantum mechanical properties of the electron include an intrinsic angular momentum ( spin) of a half-integer value, expressed in units of the reduced Planck constant, . Being fermions, no two electrons can occupy the same quantum state, in accordance with the Pauli exclusion principle. Like all elementary particles, electrons exhibit properties of both particles and waves: They can collide with other particles and can be diffracted like light. The wave properties of electrons are easier to observe with experiments than those of other particles like neutrons and protons because electrons have a lower mass and hence a longer de Broglie wavele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zinc
Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic table. In some respects, zinc is chemically similar to magnesium: both elements exhibit only one normal oxidation state (+2), and the Zn2+ and Mg2+ ions are of similar size.The elements are from different metal groups. See periodic table. Zinc is the 24th most abundant element in Earth's crust and has five stable isotopes. The most common zinc ore is sphalerite (zinc blende), a zinc sulfide mineral. The largest workable lodes are in Australia, Asia, and the United States. Zinc is refined by froth flotation of the ore, roasting, and final extraction using electricity ( electrowinning). Zinc is an essential trace element for humans, animals, plants and for microorganisms and is necessary for prenatal and postnatal development. It ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Field
A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to the magnetic field. A permanent magnet's magnetic field pulls on ferromagnetic materials such as iron, and attracts or repels other magnets. In addition, a nonuniform magnetic field exerts minuscule forces on "nonmagnetic" materials by three other magnetic effects: paramagnetism, diamagnetism, and antiferromagnetism, although these forces are usually so small they can only be detected by laboratory equipment. Magnetic fields surround magnetized materials, and are created by electric currents such as those used in electromagnets, and by electric fields varying in time. Since both strength and direction of a magnetic field may vary with location, it is described mathematically by a function assigning a vector to each point of space, cal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zeeman Effect
The Zeeman effect (; ) is the effect of splitting of a spectral line into several components in the presence of a static magnetic field. It is named after the Dutch physicist Pieter Zeeman, who discovered it in 1896 and received a Nobel prize for this discovery. It is analogous to the Stark effect, the splitting of a spectral line into several components in the presence of an electric field. Also similar to the Stark effect, transitions between different components have, in general, different intensities, with some being entirely forbidden (in the dipole approximation), as governed by the selection rules. Since the distance between the Zeeman sub-levels is a function of magnetic field strength, this effect can be used to measure magnetic field strength, e.g. that of the Sun and other stars or in laboratory plasmas. The Zeeman effect is very important in applications such as nuclear magnetic resonance spectroscopy, electron spin resonance spectroscopy, magnetic resonance imagin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pierre Weiss
Pierre-Ernest Weiss (25 March 1865, Mulhouse – 24 October 1940, Lyon) was a French physicist who specialized in magnetism. He developed the Magnetic domain, domain theory of ferromagnetism in 1907. Magnetic domain, Weiss domains and the Weiss magneton are named after him. Weiss also developed the molecular or mean field theory, which is often called Weiss-mean-field theory, that led to the discovery of the Curie–Weiss law. Alongside Auguste Picard, Pierre Weiss is considered one of the first discoverers of the Magnetic refrigeration, magnetocaloric effect in 1917. Pierre Weiss made several experimental discoveries that led to the development of the strongest electromagnets of the beginning of the 20th century. He worked at the universities of University of Rennes, Rennes, University of Lyon, Lyon, ETH Zurich where he was raised, and finally at University of Strasbourg, Strasbourg. In these academic institutions he founded several renown laboratories. Life Pierre Weiss wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetism
Magnetism is the class of physical attributes that are mediated by a magnetic field, which refers to the capacity to induce attractive and repulsive phenomena in other entities. Electric currents and the magnetic moments of elementary particles give rise to a magnetic field, which acts on other currents and magnetic moments. Magnetism is one aspect of the combined phenomena of electromagnetism. The most familiar effects occur in ferromagnetic materials, which are strongly attracted by magnetic fields and can be magnetized to become permanent magnets, producing magnetic fields themselves. Demagnetizing a magnet is also possible. Only a few substances are ferromagnetic; the most common ones are iron, cobalt, and nickel and their alloys. The rare-earth metals neodymium and samarium are less common examples. The prefix ' refers to iron because permanent magnetism was first observed in lodestone, a form of natural iron ore called magnetite, Fe3O4. All substances exhibit some type of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jules Violle
Jules Louis Gabriel Violle (16 November 1841 – 12 September 1923) was a French physicist and inventor. He is notable for having determined the solar constant at Mont Blanc in 1875, and, in 1881, for proposing a standard for luminous intensity, called the Violle, equal to the light emitted by 1 cm² of platinum at its melting point. It was notable as the first unit of light intensity that did not depend on the properties of a particular lamp. This was much larger than traditional measures such as candlepower, so the standard SI unit candela was originally defined in 1946 as 1/60 Violle. Throughout his life, Violle taught at several colleges including the University of Lyon and the Conservatoire des Arts et Métiers in Paris. He was one of the founders of the Institut d'optique théorique et appliquée and the École supérieure d'optique. He improved and invented a number of devices for measuring radiation, and determined the freezing and melting points of palladium. V ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Toulouse
Toulouse ( , ; oc, Tolosa ) is the prefecture of the French department of Haute-Garonne and of the larger region of Occitania. The city is on the banks of the River Garonne, from the Mediterranean Sea, from the Atlantic Ocean and from Paris. It is the fourth-largest city in France after Paris, Marseille and Lyon, with 493,465 inhabitants within its municipal boundaries (2019 census); its metropolitan area has a population of 1,454,158 inhabitants (2019 census). Toulouse is the central city of one of the 20 French Métropoles, with one of the three strongest demographic growth (2013-2019). Toulouse is the centre of the European aerospace industry, with the headquarters of Airbus, the SPOT satellite system, ATR and the Aerospace Valley. It hosts the CNES's Toulouse Space Centre (CST) which is the largest national space centre in Europe, but also, on the military side, the newly created NATO space centre of excellence and the French Space Command and Space Academy. Thales ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Academic Rank In France
An academy ( Attic Greek: Ἀκαδήμεια; Koine Greek Ἀκαδημία) is an institution of secondary or tertiary higher learning (and generally also research or honorary membership). The name traces back to Plato's school of philosophy, founded approximately 385 BC at Akademia, a sanctuary of Athena, the goddess of wisdom and skill, north of Athens, Greece. Etymology The word comes from the ''Academy'' in ancient Greece, which derives from the Athenian hero, '' Akademos''. Outside the city walls of Athens, the gymnasium was made famous by Plato as a center of learning. The sacred space, dedicated to the goddess of wisdom, Athena, had formerly been an olive grove, hence the expression "the groves of Academe". In these gardens, the philosopher Plato conversed with followers. Plato developed his sessions into a method of teaching philosophy and in 387 BC, established what is known today as the Old Academy. By extension, ''academia'' has come to mean the accumulatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
