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Quasielastic Neutron Scattering
Quasielastic neutron scattering (QENS) designates a limiting case of inelastic neutron scattering, characterized by energy transfers being small compared to the incident energy of the scattered particles. In a more strict meaning, it denotes scattering processes where dynamics in the sample (such as diffusive dynamics) lead to a broadening of the incident neutron spectrum, in contrast to, e.g., the scattering from a diffusionless crystal, where the scattered neutron energy spectrum consists of an elastic line (corresponding to no energy transfer with the sample) and a number of well-separated inelastic lines due to the creation or annihilation of phonons with specific energies. The term quasielastic scattering was originally coined in nuclear physics. It was applied to thermal neutron scattering since the early 1960s, notably in an article by Leon van Hove and in a highly cited one by Pierre Gilles de Gennes. QENS is typically investigated on high-resolution spectrometers (neutro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limiting Case (mathematics)
In mathematics, a limiting case of a mathematical object is a special case that arises when one or more components of the object take on their most extreme possible values. For example: * In statistics, the limiting case of the binomial distribution is the Poisson distribution. As the number of events tends to infinity in the binomial distribution, the random variable changes from the binomial to the Poisson distribution. *A circle is a limiting case of various other figures, including the Cartesian oval, the ellipse, the superellipse, and the Cassini oval. Each type of figure is a circle for certain values of the defining parameters, and the generic figure appears more like a circle as the limiting values are approached. *Archimedes calculated an approximate value of π by treating the circle as the limiting case of a regular polygon with 3 × 2''n'' sides, as ''n'' gets large. *In electricity and magnetism, the long wavelength limit is the limiting case when the wavelength is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methyl Group Rotation
In organic chemistry, a methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms, having chemical formula . In formulas, the group is often abbreviated as Me. This hydrocarbon group occurs in many organic compounds. It is a very stable group in most molecules. While the methyl group is usually part of a larger molecule, bounded to the rest of the molecule by a single covalent bond (), it can be found on its own in any of three forms: methanide anion (), methylium cation () or methyl radical (). The anion has eight valence electrons, the radical seven and the cation six. All three forms are highly reactive and rarely observed. Methyl cation, anion, and radical Methyl cation The methylium cation () exists in the gas phase, but is otherwise not encountered. Some compounds are considered to be sources of the cation, and this simplification is used pervasively in organic chemistry. For example, protonation of methanol gives an electr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Berlin
Berlin ( , ) is the capital and largest city of Germany by both area and population. Its 3.7 million inhabitants make it the European Union's most populous city, according to population within city limits. One of Germany's sixteen constituent states, Berlin is surrounded by the State of Brandenburg and contiguous with Potsdam, Brandenburg's capital. Berlin's urban area, which has a population of around 4.5 million, is the second most populous urban area in Germany after the Ruhr. The Berlin-Brandenburg capital region has around 6.2 million inhabitants and is Germany's third-largest metropolitan region after the Rhine-Ruhr and Rhine-Main regions. Berlin straddles the banks of the Spree, which flows into the Havel (a tributary of the Elbe) in the western borough of Spandau. Among the city's main topographical features are the many lakes in the western and southeastern boroughs formed by the Spree, Havel and Dahme, the largest of which is Lake Müggelsee. Due to its l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Institut Laue-Langevin
An institute is an organisational body created for a certain purpose. They are often research organisations (research institutes) created to do research on specific topics, or can also be a professional body. In some countries, institutes can be part of a university or other institutions of higher education, either as a group of departments or an autonomous educational institution without a traditional university status such as a "university institute" (see Institute of Technology). In some countries, such as South Korea and India, private schools are sometimes referred to as institutes, and in Spain, secondary schools are referred to as institutes. Historically, in some countries institutes were educational units imparting vocational training and often incorporating libraries, also known as mechanics' institutes. The word "institute" comes from a Latin word ''institutum'' meaning "facility" or "habit"; from ''instituere'' meaning "build", "create", "raise" or "educate". ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autrans
Autrans () is a former commune in the Isère department in the Rhône-Alpes region of south-eastern France. On 1 January 2016, it was merged into the new commune of Autrans-Méaudre-en-Vercors. At the 1968 Winter Olympics in Grenoble, it hosted the biathlon, cross-country skiing, Nordic combined, and the ski jumping normal hill events. The inhabitants of the commune are known as ''Autranais'' or ''Autranaises''. The commune has been awarded one flower by the ''National Council of Towns and Villages in Bloom'' in the ''Competition of cities and villages in Bloom''. Geography Autrans is located on the Vercors Plateau in the Vercors Regional Natural Park some 10 km west of Grenoble and 11 km east of Vinay. Access to the commune is solely by the D106C which branches north from the D106 and passes in a loop through the village then back south to Méaudre. A local road goes north from the village along to the valley to the ski fields in the north of the commune. There i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
J-PARC
J-PARC (Japan Proton Accelerator Research Complex) is a high intensity proton accelerator facility. It is a joint project between KEK and JAEA and is located at the Tokai campus of JAEA. J-PARC aims for the frontier in materials and life sciences, and nuclear and particle physics. J-PARC uses high intensity proton beams to create high intensity secondary beams of neutrons, hadrons, and neutrinos. Components J-PARC includes three main parts: the 400 MeV proton linear accelerator, the 3 GeV Rapid Cycling Synchrotron (RCS), and the 30 GeV Main Ring (MR) synchrotron. There are two main experimental areas: the Materials and Life Science Experimental Facility (MLF), where the proton beam from the RCS is used to create beams of either neutrons or muons for further study, and the Hadron Facility (HD), where the beam from the main ring is used to create heavy hadronic particles such as pions and kaons. The main ring beam is also used to create neutrino beams for analysis at the Kami ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paul-Scherrer-Institut
The Paul Scherrer Institute (PSI) is a multi-disciplinary research institute for natural and engineering sciences in Switzerland. It is located in the Canton of Aargau in the municipalities Villigen and Würenlingen on either side of the River Aare, and covers an area over 35 hectares in size. Like ETH Zurich and EPFL, PSI belongs to the Swiss Federal Institutes of Technology Domain of the Swiss Confederation. The PSI employs around 2,100 people. It conducts basic and applied research in the fields of matter and materials, human health, and energy and the environment. About 37% of PSI's research activities focus on material sciences, 24% on life sciences, 19% on general energy, 11% on nuclear energy and safety, and 9% on particle physics. PSI develops, builds and operates large and complex research facilities and makes them available to the national and international scientific communities. In 2017, for example, more than 2,500 researchers from 60 different countries came to PS ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hahn-Meitner-Institut
Helmholtz-Zentrum Berlin für Materialien und Energie (Helmholtz Centre for Materials and Energy, HZB) is part of the Helmholtz Association of German Research Centres. The institute studies the structure and dynamics of materials and investigates solar cell technology. It also runs the third-generation BESSY II synchrotron in Adlershof. Until the end of 2019 it ran the 10 megawatt BER II nuclear research reactor at the Lise Meitner campus in Wannsee. History Following the renaming of Hahn-Meitner-Institut Berlin GmbH to Helmholtz-Zentrum Berlin für Materialien und Energie GmbH on 5 June 2008, the legal merger of Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung (BESSY) with HZB became visible on 1 January 2009. The Hahn-Meitner-Institut Berlin für Kernforschung (HMI), named after Otto Hahn and Lise Meitner, was named 14 March 1959 in Berlin-Wannsee to operate the BER I research reactor that began operation with 50 kW on 24 July 1958, then named Institu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Studsvik
Studsvik is a supplier of nuclear analysis software and specialised services to the international nuclear industry. The company is headquartered in Nyköping, Sweden, and has five divisions: Sweden, United Kingdom, Germany, the United States, and Global Services. There are 1,100 employees in 8 countries. The company's shares are listed on the Nasdaq OMX Stockholm. Studsvik offers advanced technical services to the international nuclear power industry in areas including fuel analysis software, waste treatment, decommissioning, engineering and services, and operating efficiency. The company was founded in Stockholm in 1947, as AB Atomenergi, to develop and operate nuclear power stations in Sweden. Originally it was 57% government-owned; during the 1960s, the government acquired the entirety of the shares, but then in the 1970s, government funding was reduced and the company became entirely industry-owned and changed its name to Studsvik Energiteknik AB. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ISIS Neutron Source
The ISIS Neutron and Muon Source is a pulsed neutron and muon source, established 1984 at the Rutherford Appleton Laboratory of the Science and Technology Facilities Council, on the Harwell Science and Innovation Campus in Oxfordshire, United Kingdom. It uses the techniques of muon spectroscopy and neutron scattering to probe the structure and dynamics of condensed matter on a microscopic scale ranging from the subatomic to the macromolecular. Hundreds of experiments are performed every year at the facility by researchers from around the world, in diverse science areas such as physics, chemistry, materials engineering, earth sciences, biology and archaeology. Background physics Neutrons are uncharged constituents of atoms and penetrate materials well, deflecting only from the nuclei of atoms. The statistical accumulation of deflected neutrons at different positions beyond the sample can be used to find the structure of a material, and the loss or gain of energy by neutron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Structural Relaxation
A structure is an arrangement and organization of interrelated elements in a material object or system, or the object or system so organized. Material structures include man-made objects such as buildings and machines and natural objects such as biological organisms, minerals and chemicals. Abstract structures include data structures in computer science and musical form. Types of structure include a hierarchy (a cascade of one-to-many relationships), a network featuring many-to-many links, or a lattice featuring connections between components that are neighbors in space. Load-bearing Buildings, aircraft, skeletons, anthills, beaver dams, bridges and salt domes are all examples of load-bearing structures. The results of construction are divided into buildings and non-building structures, and make up the infrastructure of a human society. Built structures are broadly divided by their varying design approaches and standards, into categories including building structure ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
