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Meredith Gwynne Evans
Meredith Gwynne Evans, FRS (2 December 1904 – 25 December 1952) was a British physical chemist, who made important theoretical contributions in the study of chemical reaction rates and reaction mechanisms. Together with Henry Eyring and Michael Polanyi, Meredith Gwynne Evans is one of the founders of the transition state theory. Early life and education Meredith Gwynne Evans was born in Atherton, a suburb of Manchester, on 2 December 1904 and the son of Frederick George Evans, an elementary schoolmaster from Pembrokeshire, Wales, and his wife, Margaretta Eleanora Williams. He was the eldest son in a family of three sons and one daughter. Evans attended the elementary school at which his father was Headmaster, won a County Scholarship to Leigh Grammar School, and was educated at the University of Manchester. C. E. H. Bawn, Hugh Taylor, Muriel Tomlinson and Harold Hartley, "Obituary notices: Meredith Gwynne Evans, 1904–1952; James William McBain, 1882–1953; Sydney Glenn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atherton, Greater Manchester
Atherton () is a town in Greater Manchester, England and historically a part of Lancashire. The town, including Hindsford, Howe Bridge and Hag Fold, is south of Bolton, east of Wigan, and northwest of Manchester. From the 17th century, for about 300 years, Atherton was known as Chowbent, which was frequently shortened to Bent, the town's old nickname. During the Industrial Revolution, the town was a key part of the Manchester Coalfield. Atherton was associated with coal mining and nail manufacture from the 14th century, encouraged by outcropping coal seams. At the beginning of the 20th century, the town was described as "the centre of a district of collieries, cotton mills and iron-works, which cover the surface of the country with their inartistic buildings and surroundings, and are linked together by the equally unlovely dwellings of the people". Atherton's last deep coal mine closed in 1966, and the last cotton mill closed in 1999. Today the town is the third-largest ret ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Michael Polanyi
Michael Polanyi (; hu, Polányi Mihály; 11 March 1891 – 22 February 1976) was a Hungarian-British polymath, who made important theoretical contributions to physical chemistry, economics, and philosophy. He argued that positivism supplies an imperfect account of knowing as no observer is perfectly impartial. His wide-ranging research in physical science included chemical kinetics, x-ray diffraction, and adsorption of gases. He pioneered the theory of fibre diffraction analysis in 1921, and the dislocation theory of plastic deformation of ductile metals and other materials in 1934. He immigrated to Germany, in 1926 becoming a chemistry professor at the Kaiser Wilhelm Institute in Berlin, and then in 1933 to England, becoming first a chemistry professor, and then a social sciences professor at the University of Manchester. Two of his pupils, and his son John Charles Polanyi won Nobel Prizes in Chemistry. In 1944 Polanyi was elected to the Royal Society. The contribution ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transition State Theory
In chemistry, transition state theory (TST) explains the reaction rates of elementary chemical reactions. The theory assumes a special type of chemical equilibrium (quasi-equilibrium) between reactants and activated transition state complexes. TST is used primarily to understand qualitatively how chemical reactions take place. TST has been less successful in its original goal of calculating absolute reaction rate constants because the calculation of absolute reaction rates requires precise knowledge of potential energy surfaces, but it has been successful in calculating the standard enthalpy of activation (Δ''H''‡, also written Δ‡''H''ɵ), the standard entropy of activation (Δ''S''‡ or Δ‡''S''ɵ), and the standard Gibbs energy of activation (Δ''G''‡ or Δ‡''G''ɵ) for a particular reaction if its rate constant has been experimentally determined. (The ‡ notation refers to the value of interest ''at the transition state''; Δ''H''‡ is the difference between the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Kinetics
Chemical kinetics, also known as reaction kinetics, is the branch of physical chemistry that is concerned with understanding the rates of chemical reactions. It is to be contrasted with chemical thermodynamics, which deals with the direction in which a reaction occurs but in itself tells nothing about its rate. Chemical kinetics includes investigations of how experimental conditions influence the speed of a chemical reaction and yield information about the reaction's mechanism and transition states, as well as the construction of mathematical models that also can describe the characteristics of a chemical reaction. History In 1864, Peter Waage and Cato Guldberg pioneered the development of chemical kinetics by formulating the law of mass action, which states that the speed of a chemical reaction is proportional to the quantity of the reacting substances.C.M. Guldberg and P. Waage,"Studies Concerning Affinity" ''Forhandlinger i Videnskabs-Selskabet i Christiania'' (1864), 35P. W ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eyring Equation
The Eyring equation (occasionally also known as Eyring–Polanyi equation) is an equation used in chemical kinetics to describe changes in the rate of a chemical reaction against temperature. It was developed almost simultaneously in 1935 by Henry Eyring, Meredith Gwynne Evans and Michael Polanyi. The equation follows from the transition state theory, also known as activated-complex theory. If one assumes a constant enthalpy of activation and constant entropy of activation, the Eyring equation is similar to the empirical Arrhenius equation, despite the Arrhenius equation being empirical and the Eyring equation based on statistical mechanical justification. General form The general form of the Eyring–Polanyi equation somewhat resembles the Arrhenius equation: \ k = \frac e^ where k is the rate constant, \Delta G^\ddagger is the Gibbs energy of activation, \kappa is the transmission coefficient, k_\mathrm is the Boltzmann constant, T is the temperature, and h is the Pl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lawrence Bragg
Sir William Lawrence Bragg, (31 March 1890 – 1 July 1971) was an Australian-born British physicist and X-ray crystallography, X-ray crystallographer, discoverer (1912) of Bragg's law, Bragg's law of X-ray diffraction, which is basic for the determination of crystal structure. He was joint recipient (with his father, William Henry Bragg) of the Nobel Prize in Physics in 1915, "For their services in the analysis of crystal structure by means of X-rays"; an important step in the development of X-ray crystallography. Bragg was knight bachelor, knighted in 1941. As of 2021, he is the youngest ever List of Nobel laureates, Nobel laureate in physics, having received the award at the age of 25 years. Bragg was the director of the Cavendish Laboratory, Cambridge, when the discovery of the structure of DNA was reported by James D. Watson and Francis Crick in February 1953. Biography Early years Bragg was born in Adelaide, South Australia to William Henry Bragg, Sir William Henry B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Douglas Hartree
Douglas Rayner Hartree (27 March 1897 – 12 February 1958) was an English mathematician and physicist most famous for the development of numerical analysis and its application to the Hartree–Fock equations of atomic physics and the construction of a differential analyser using Meccano. Early life and education Douglas Hartree was born in Cambridge, England. His father, William, was a lecturer in engineering at the University of Cambridge and his mother, Eva Rayner, was president of the National Council of Women of Great Britain and first woman to be mayor of the city of Cambridge. One of his great-grandfathers was Samuel Smiles; another was the marine engineer William Hartree, partner of John Penn. Douglas Hartree was the oldest of three sons that survived infancy. A brother and sister died in infancy when he was still a child, but his two brothers would later also die. Hartree's 7-year-old brother John Edwin died when Hartree was 17, and Hartree's 22-year-old brot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quantum Mechanics
Quantum mechanics is a fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including quantum chemistry, quantum field theory, quantum technology, and quantum information science. Classical physics, the collection of theories that existed before the advent of quantum mechanics, describes many aspects of nature at an ordinary (macroscopic) scale, but is not sufficient for describing them at small (atomic and subatomic) scales. Most theories in classical physics can be derived from quantum mechanics as an approximation valid at large (macroscopic) scale. Quantum mechanics differs from classical physics in that energy, momentum, angular momentum, and other quantities of a bound system are restricted to discrete values ( quantization); objects have characteristics of both particles and waves (wave–particle duality); and there are limits to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chabazite
Chabazite ()The New Oxford Dictionary of English (1998) - p. 300 "chabazite /'kabəzʌɪt/ noun "A colourless, pink or yellow zeolite mineral, typically occurring as rhombohedral crystals.". is a tectosilicate mineral of the zeolite group, closely related to gmelinite, with the chemical formula . Recognized varieties include Chabazite-Ca, Chabazite-K, Chabazite-Na, and Chabazite-Sr, depending on the prominence of the indicated cation. Chabazite crystallizes in the triclinic crystal system with typically rhombohedral shaped crystals that are pseudo-cubic. The crystals are typically twinned, and both contact twinning and penetration twinning may be observed. They may be colorless, white, orange, brown, pink, green, or yellow. The hardness ranges from 3 to 5 and the specific gravity from 2.0 to 2.2. The luster is vitreous. It was named chabasie in 1792 by Bosc d'Antic and later changed to the current spelling. Chabazite occurs most commonly in voids and amygdules in basaltic r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nobel Prize In Chemistry
) , image = Nobel Prize.png , alt = A golden medallion with an embossed image of a bearded man facing left in profile. To the left of the man is the text "ALFR•" then "NOBEL", and on the right, the text (smaller) "NAT•" then "MDCCCXXXIII" above, followed by (smaller) "OB•" then "MDCCCXCVI" below. , awarded_for = Outstanding contributions in chemistry , presenter = Royal Swedish Academy of Sciences , location = Stockholm, Sweden , reward = 9 million SEK (2017) , year = 1901 , holder = Carolyn R. Bertozzi, Morten P. Meldal and Karl Barry Sharpless (2022) , most_awards = Frederick Sanger and Karl Barry Sharpless (2) , website nobelprize.org, previous = 2021 , year2=2022, main=2022, next=2023 The Nobel Prize in Chemistry is awarded annually by the Royal Swedish Academy of Sciences to scientists in the various fields of chemistry. It is one of the five Nobel Prizes established by the will of Alfred Nobel in 1895, awarded for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Meurig Thomas
Sir John Meurig Thomas (15 December 193213 November 2020), also known as JMT, was a Welsh scientist, educator, university administrator, and historian of science primarily known for his work on heterogeneous catalysis, solid-state chemistry, and surface and materials science. He was one of the founders of solid-state chemistry, starting with his work at the University of Wales, Bangor, in 1958 when he investigated the various ways in which dislocations influence the chemical, electronic and excitonic properties of a range of solids. He was one of the first to exploit electron microscopy as a chemical tool, especially to deduce active-site reactivities from the surface topography of many minerals and crystal hydrates. At the University of Aberystwyth (1969–1978) he elucidated the surface chemistry of diamond, clay minerals, metals and intercalates by pioneering UV and X-ray photoelectron spectroscopy. He also initiated the field of crystal engineering of organic molecules. A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardiff University
, latin_name = , image_name = Shield of the University of Cardiff.svg , image_size = 150px , caption = Coat of arms of Cardiff University , motto = cy, Gwirionedd, Undod a Chytgord , mottoeng = Truth, Unity and Concord , established = 1883 (/)2005 (independent university status) , type = Public , endowment = £45.5 million (2021) , budget = £603.4 million (2020–21) , total_staff = 6,900 (2019/20) , academic_staff = 3,350 (2019/20) , chancellor = Jenny Randerson , vice_chancellor = Colin Riordan , students = () , undergrad = () , postgrad = () , other = , city = Cardiff , country = Wales, United Kingdom , coor = , campus = Urban , colours = , mascot = , affiliations = Russell Group EUAUniversities UK GW4 , website cardiff.ac.uk, logo = Cardiff University ( cy, Prifysgol Caerdydd) is a public research university in Cardiff, Wales, United Kingdom. It was established in 1883 as the University College of South Wales and Monmouthshire ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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