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Dynamical Diffraction
The dynamical theory of diffraction describes the interaction of waves with a regular lattice. The wave fields traditionally described are X-rays, neutrons or electrons and the regular lattice are atomic crystal structures or nanometer-scale multi-layers or self-arranged systems. In a wider sense, similar treatment is related to the interaction of light with optical band-gap materials or related wave problems in acoustics. Principle The dynamical theory of diffraction considers the wave field in the periodic potential of the crystal and takes into account all multiple scattering effects. Unlike the kinematic theory of diffraction which describes the approximate position of Bragg or Laue diffraction peaks in reciprocal space, dynamical theory corrects for refraction, shape and width of the peaks, extinction and interference effects. Graphical representations are described in dispersion surfaces around reciprocal lattice points which fulfill the boundary conditions at the crystal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Refraction
In physics, refraction is the redirection of a wave as it passes from one medium to another. The redirection can be caused by the wave's change in speed or by a change in the medium. Refraction of light is the most commonly observed phenomenon, but other waves such as sound waves and water waves also experience refraction. How much a wave is refracted is determined by the change in wave speed and the initial direction of wave propagation relative to the direction of change in speed. For light, refraction follows Snell's law, which states that, for a given pair of media, the ratio of the sines of the angle of incidence ''θ1'' and angle of refraction ''θ2'' is equal to the ratio of phase velocities (''v''1 / ''v''2) in the two media, or equivalently, to the refractive indices (''n''2 / ''n''1) of the two media. :\frac =\frac=\frac Optical prisms and lenses use refraction to redirect light, as does the human eye. The refractive index of materials varies with the wavelengt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anomalous Absorption
Anomaly may refer to: Science Natural *Anomaly (natural sciences) **Atmospheric anomaly **Geophysical anomaly Medical *Congenital anomaly (birth defect), a disorder present at birth ** Physical anomaly, a deformation of an anatomical structure ***Congenital vertebral anomaly, any of several malformations of the spine **Collie eye anomaly, eye disease of dogs *** Coronary artery anomaly, a congenital abnormality in the heart ***Ebstein's anomaly, a congenital heart defect in which the opening of the tricuspid valve is displaced *** Uhl anomaly, a congenital heart disease affecting the myocardial muscle *** Vaginal anomalies Biology * Anomalous, a species of moth in the Noctuid family * Chromosome anomaly, a disorder caused by a structural error in a chromosome or an atypical number of chromosomes *Genetic anomaly, a disorder caused by mutation *Teratology, the study of developmental anomalies Physics *Anomalous diffusion is the movement of molecules from a region of lower conc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kato Fringes
Kato or Katō may refer to: Places *Kato, Guyana, a village in Guyana *Katō, Hyōgo, a city in Hyōgo Prefecture, Japan *Katō District, Hokkaido, a district located in Tokachi Subprefecture, Hokkaido, Japan * Katowice, a city in Southern Poland, often abbreviated to Kato *Mankato, a city in Southern Minnesota, often abbreviated to Kato Brands and enterprises * Kato Airline, a small airline based in Evenes, Norway *Kato Airport, an airport in Guyana *Kato Precision Railroad Models, a manufacturer of model railroad equipment Fictional characters *Kato (The Green Hornet), comic book character *Kato, the main antagonist in Astrid Lindgren's book '' Mio, My Son'' *Cato Fong (originally spelled "Kato"), character from the ''Pink Panther'' film series, see list of The Pink Panther characters People *Kato (name), a given name and surname *Katō (surname), a Japanese surname Nickname or stage name *Kato (DJ), Danish DJ * Kato (producer), Korean-American music producer * Paul Diamon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Borrmann Triangle
Borrmann is a German surname. Notable people with the surname include: * Elmar Borrmann (born 1957), German fencer * Gerhard Borrmann (1908–2006), German physicist * Joachim Borrmann, recipient of Knight's Cross of the Iron Cross * Mechtild Borrmann (born 1960), German writer, author of several detective novels * Richard Borrmann (1852–1931), German architect and classical archaeologist * Robert Borrmann, birth name of Eniac, a German composer and record producer specializing in house music and techno * Bettina Borrmann Wells (1874–?), Bavarian-born English suffragette who toured the United States as an organizer and lecturer See also *the Borrmann effect (after Gerhard Borrmann), the anomalous increase in the intensity of X-rays transmitted through a crystal when it is being set up for Bragg reflection * Borman * Bormann * {{surname German-language surnames ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laue Geometry
Max Theodor Felix von Laue (; 9 October 1879 – 24 April 1960) was a German physicist who received the Nobel Prize in Physics in 1914 for his discovery of the diffraction of X-rays by crystals. In addition to his scientific endeavors with contributions in optics, crystallography, quantum theory, superconductivity, and the theory of relativity, Laue had a number of administrative positions which advanced and guided German scientific research and development during four decades. A strong objector to Nazism, he was instrumental in re-establishing and organizing German science after World War II. Biography Early years Laue was born in Pfaffendorf, now part of Koblenz, Germany, to Julius Laue and Minna Zerrenner. In 1898, after passing his '' Abitur'' in Strassburg, he began his compulsory year of military service, after which in 1899 he started to study mathematics, physics, and chemistry at the University of Strassburg, the University of Göttingen, and the Ludwig Maximili ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bragg Geometry
Bragg may refer to: Places *Bragg City, Missouri, United States *Bragg, Texas, a ghost town, United States * Bragg, West Virginia, an unincorporated community, United States *Electoral district of Bragg, a state electoral district in South Australia, Australia *Bragg Islands, Graham Land, Antarctica * Bragg (crater), a crater on the Moon People * Bragg (surname), people with the surname Other uses *Bragg Institute, a neutron and X-ray scattering group in Australia *Bragg Box, a type of traveling museum exhibit invented by Laura Bragg *Bragg Communications, a Canadian cable television provider *Bragg Live Food Products, Inc, a health food company started by Paul Bragg *Bragg's Mill, Ashdon, an English windmill *Bragg House (other), various houses on the National Register of Historic Places *Bragg Memorial Stadium, a football stadium in Tallahassee, Florida Physics *Bragg's law *Distributed Bragg reflector * Fiber Bragg grating See also *Brag (other) *Fort Bragg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pendellösung
The Pendellösung effect or phenomenon is seen in diffraction in which there is a beating in the intensity of electromagnetic waves travelling within a crystal lattice. It was predicted by P. P. Ewald in 1916 and first observed in electron diffraction of magnesium oxide in 1942. At the exit surface of a photonic crystal (PhC), the intensity of the diffracted wave can be periodically modulated, showing a maximum in the "positive" (forward diffracted) or in the "negative" (diffracted) direction, depending on the crystal slab thickness. The Pendellösung effect in photonic crystal A photonic crystal is an optical nanostructure in which the refractive index changes periodically. This affects the propagation of light in the same way that the structure of natural crystals gives rise to X-ray diffraction and that the atomic ...s can be understood as a beating phenomenon due to the phase modulation between coexisting plane wave components, propagating in the same direction. This ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Band Gap
In solid-state physics, a band gap, also called an energy gap, is an energy range in a solid where no electronic states can exist. In graphs of the electronic band structure of solids, the band gap generally refers to the energy difference (in electron volts) between the top of the valence band and the bottom of the conduction band in insulators and semiconductors. It is the energy required to promote a valence electron bound to an atom to become a conduction electron, which is free to move within the crystal lattice and serve as a charge carrier to conduct electric current. It is closely related to the HOMO/LUMO gap in chemistry. If the valence band is completely full and the conduction band is completely empty, then electrons cannot move within the solid because there are no available states. If the electrons are not free to move within the crystal lattice, then there is no generated current due to no net charge carrier mobility. However, if some electrons transfer from th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Energy
In physics, energy (from Ancient Greek: ἐνέργεια, ''enérgeia'', “activity”) is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of heat and light. Energy is a conserved quantity—the law of conservation of energy states that energy can be converted in form, but not created or destroyed. The unit of measurement for energy in the International System of Units (SI) is the joule (J). Common forms of energy include the kinetic energy of a moving object, the potential energy stored by an object (for instance due to its position in a field), the elastic energy stored in a solid object, chemical energy associated with chemical reactions, the radiant energy carried by electromagnetic radiation, and the internal energy contained within a thermodynamic system. All living organisms constantly take in and release energy. Due to mass–energy equivalence, any object that has mass whe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Darwin Plateau
Darwin may refer to: Common meanings * Charles Darwin (1809–1882), English naturalist and writer, best known as the originator of the theory of biological evolution by natural selection * Darwin, Northern Territory, a territorial capital city in Australia Arts and entertainment * ''Darwin'' (1920 film), a German silent film * ''Darwin'' (2011 film), a documentary * ''Darwin'' (2015 film), a science fiction film by Alain Desrochers * Darwin (''seaQuest DSV''), a dolphin in the TV series ''seaQuest DSV'' * ''Darwin!'', a 1972 album by Banco del Mutuo Soccorso * '' Darwin: The Life of a Tormented Evolutionist'', a 1991 biography of Charles Darwin * Darwin (Marvel Comics), a fictional character in the Marvel Comics Universe associated with the X-Men * Darwin Watterson, a character from the 2011 TV series ''The Amazing World of Gumball'' Astronomy * 1991 Darwin, a main-belt asteroid * Darwin (lunar crater) * Darwin (Martian crater) * Darwin (spacecraft), a European Space Agenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Total Reflection
Total internal reflection (TIR) is the optical phenomenon in which waves arriving at the interface (boundary) from one medium to another (e.g., from water to air) are not refracted into the second ("external") medium, but completely reflected back into the first ("internal") medium. It occurs when the second medium has a higher wave speed (i.e., lower refractive index) than the first, and the waves are incident at a sufficiently oblique angle on the interface. For example, the water-to-air surface in a typical fish tank, when viewed obliquely from below, reflects the underwater scene like a mirror with no loss of brightness (Fig.1). TIR occurs not only with electromagnetic waves such as light and microwaves, but also with other types of waves, including sound and water waves. If the waves are capable of forming a narrow beam (Fig.2), the reflection tends to be described in terms of "rays" rather than waves; in a medium whose properties are independent of direction, such as air, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
