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Quasielastic Scattering
In physics, quasielastic scattering designates a limiting case of inelastic scattering, characterized by energy transfers being small compared to the incident energy of the scattered particles. The term was originally coined in nuclear physics. It was applied to thermal neutron scattering by Leon van Hove and Pierre Gilles de Gennes (quasielastic neutron scattering, QENS). Finally, it is sometimes used for dynamic light scattering Dynamic light scattering (DLS) is a technique in physics that can be used to determine the size distribution profile of small particles in suspension or polymers in solution. In the scope of DLS, temporal fluctuations are usually analyzed using ... (also known by the more expressive term photon correlation spectroscopy). References {{Reflist Nuclear physics Neutron scattering ... [...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 i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inelastic Scattering
In chemistry, nuclear physics, and particle physics, inelastic scattering is a fundamental scattering process in which the kinetic energy of an incident particle is not conserved (in contrast to elastic scattering). In an inelastic scattering process, some of the energy of the incident particle is lost or increased. Although the term is historically related to the concept of inelastic collision in dynamics, the two concepts are quite distinct; inelastic collision in dynamics refers to processes in which the total macroscopic kinetic energy is not conserved. In general, scattering due to inelastic collisions will be inelastic, but, since elastic collisions often transfer kinetic energy between particles, scattering due to elastic collisions can also be ''in''elastic, as in Compton scattering meaning the two particles in the collision transfer energy causing a loss of energy in one particle. Electrons When an electron is the incident particle, the probability of inelastic scattering ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neutron Scattering
Neutron scattering, the irregular dispersal of free neutrons by matter, can refer to either the naturally occurring physical process itself or to the man-made experimental techniques that use the natural process for investigating materials. The natural/physical phenomenon is of elemental importance in nuclear engineering and the nuclear sciences. Regarding the experimental technique, understanding and manipulating neutron scattering is fundamental to the applications used in crystallography, physics, physical chemistry, biophysics, and materials research. Neutron scattering is practiced at research reactors and spallation neutron sources that provide neutron radiation of varying intensities. Neutron diffraction (elastic scattering) techniques are used for analyzing structures; where inelastic neutron scattering is used in studying atomic vibrations and other excitations. Scattering of fast neutrons "Fast neutrons" (see neutron temperature) have a kinetic energy above 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leon Van Hove
Leon, Léon (French) or León (Spanish) may refer to: Places Europe * León, Spain, capital city of the Province of León * Province of León, Spain * Kingdom of León, an independent state in the Iberian Peninsula from 910 to 1230 and again from 1296 to 1301 * León (historical region), composed of the Spanish provinces León, Salamanca, and Zamora * Viscounty of Léon, a feudal state in France during the 11th to 13th centuries * Saint-Pol-de-Léon, a commune in Brittany, France * Léon, Landes, a commune in Aquitaine, France * Isla de León, a Spanish island * Leon (Souda Bay), an islet in Souda Bay, Chania, on the island of Crete North America * León, Guanajuato, Mexico, a large city * Leon, California, United States, a ghost town * Leon, Iowa, United States * Leon, Kansas, United States * Leon, New York, United States * Leon, Oklahoma, United States * Leon, Virginia, United States * Leon, West Virginia, United States * Leon, Wisconsin (other), United State ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pierre Gilles De Gennes
Pierre-Gilles de Gennes (; 24 October 1932 – 18 May 2007) was a French physicist and the Nobel Prize laureate in physics in 1991. Education and early life He was born in Paris, France, and was home-schooled to the age of 12. By the age of 13, he had adopted adult reading habits and was visiting museums. Later, de Gennes studied at the École Normale Supérieure. After leaving the ''École'' in 1955, he became a research engineer at the Saclay center of the Commissariat à l'Énergie Atomique, working mainly on neutron scattering and magnetism, with advice from Anatole Abragam and Jacques Friedel. He defended his Ph.D. in 1957 at the University of Paris. Career and research In 1959, he was a postdoctoral research visitor with Charles Kittel at the University of California, Berkeley, and then spent 27 months in the French Navy. In 1961, he was assistant professor in Orsay and soon started the Orsay group on superconductors. In 1968, he switched to studying liquid crystals. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
Dynamic Light Scattering
Dynamic light scattering (DLS) is a technique in physics that can be used to determine the size distribution profile of small particles in suspension or polymers in solution. In the scope of DLS, temporal fluctuations are usually analyzed using the intensity or photon auto-correlation function (also known as photon correlation spectroscopy or quasi-elastic light scattering). In the time domain analysis, the autocorrelation function (ACF) usually decays starting from zero delay time, and faster dynamics due to smaller particles lead to faster decorrelation of scattered intensity trace. It has been shown that the intensity ACF is the Fourier transform of the power spectrum, and therefore the DLS measurements can be equally well performed in the spectral domain. DLS can also be used to probe the behavior of complex fluids such as concentrated polymer solutions. Setup A monochromatic light source, usually a laser, is shot through a polarizer and into a sample. The scattered light the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Physics
Nuclear physics is the field of physics that studies atomic nuclei and their constituents and interactions, in addition to the study of other forms of nuclear matter. Nuclear physics should not be confused with atomic physics, which studies the atom as a whole, including its electrons. Discoveries in nuclear physics have led to nuclear technology, applications in many fields. This includes nuclear power, nuclear weapons, nuclear medicine and magnetic resonance imaging, industrial and agricultural isotopes, ion implantation in materials engineering, and radiocarbon dating in geology and archaeology. Such applications are studied in the field of nuclear engineering. Particle physics evolved out of nuclear physics and the two fields are typically taught in close association. Nuclear astrophysics, the application of nuclear physics to astrophysics, is crucial in explaining the inner workings of stars and the nucleosynthesis, origin of the chemical elements. History The history o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
