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N-25 Snark On The Holloman Track
Chemistry * ''n-'', a lowercase prefix in chemistry denoting the straight-chain form of an open-chain compound In chemistry, an open-chain compound (also spelled as open chain compound) or acyclic compound (Greek prefix "α", ''without'' and "κύκλος", ''cycle'') is a compound with a linear structure, rather than a cyclic one. An open-chain compound ha ... in contrast to its branched isomer * ''N-'', an uppercase prefix in chemistry denoting that the substituent is bonded to the nitrogen, as in amines Mathematics, science and technology The italicized letter ''n'' is used in mathematics to denote an arbitrary number (usually a non-negative integer). * ''n''-ary associativity * ''n''-ary code * ''n''-ary group * ''n''-back * ''n''-body problem * ''n''-category * ''n''-category number * ''n''-connected space * ''n''-curve * ''n''-dimensional space * ''n''-dimensional sequential move puzzle * ''n''-electron valence state perturbation theory (NEVPT) * ''n''-entity * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Open-chain Compound
In chemistry, an open-chain compound (also spelled as open chain compound) or acyclic compound (Greek prefix "α", ''without'' and "κύκλος", ''cycle'') is a compound with a linear structure, rather than a cyclic one. An open-chain compound having no side chains is called a straight-chain compound (also spelled as straight chain compound). Many of the simple molecules of organic chemistry, such as the alkanes and alkenes, have both linear and ring isomers, that is, both acyclic and cyclic, with the latter often classified as aromatic. For those with 4 or more carbons, the linear forms can have straight-chain or branched-chain isomers. The lowercase prefix ''n-'' denotes the straight-chain isomer; for example, ''n''-butane is straight-chain butane, whereas ''i''-butane is isobutane. Cycloalkanes are isomers of alkenes, not of alkanes, because the ring's closure involves a C-C bond. Having no rings (aromatic or otherwise), all open-chain compounds are aliphatic. Typically in bioc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-entity
In telecommunication, a ''n''-entity is an active element in the ''n''-th layer of the Open Systems Interconnection--Reference Model (OSI-RM) that (a) interacts directly with elements, ''i.e.'', entities, of the layer immediately above or below the ''n''-th layer, (b) is defined by a unique set of rules, ''i.e.'', syntax, and information formats, including data and control formats, and (c) performs a defined set of functions. The ''n'' refers to any one of the 7 layers of the OSI-RM. In an existing layered open system, the ''n'' may refer to any given layer in the system. Layers are conventionally numbered from the lowest, ''i.e.'', the physical layer In the seven-layer OSI model of computer networking, the physical layer or layer 1 is the first and lowest layer; The layer most closely associated with the physical connection between devices. This layer may be implemented by a PHY chip. The ..., to the highest, so that the -th layer is above the ''n''-th layer and the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-vector
The ''n''-vector representation (also called geodetic normal or ellipsoid normal vector) is a three-parameter non-singular representation well-suited for replacing geodetic coordinates (latitude and longitude) for horizontal position representation in mathematical calculations and computer algorithms. Geometrically, the ''n''-vector for a given position on an ellipsoid is the outward-pointing unit vector that is normal in that position to the ellipsoid. For representing horizontal positions on Earth, the ellipsoid is a reference ellipsoid and the vector is decomposed in an Earth-centered Earth-fixed coordinate system. It behaves smoothly at all Earth positions, and it holds the mathematical one-to-one property. More in general, the concept can be applied to representing positions on the boundary of a strictly convex bounded subset of ''k''-dimensional Euclidean space, provided that that boundary is a differentiable manifold. In this general case, the ''n''-vector consist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-sphere
In mathematics, an -sphere or a hypersphere is a topological space that is homeomorphic to a ''standard'' -''sphere'', which is the set of points in -dimensional Euclidean space that are situated at a constant distance from a fixed point, called the ''center''. It is the generalization of an ordinary sphere in the ordinary three-dimensional space. The "radius" of a sphere is the constant distance of its points to the center. When the sphere has unit radius, it is usual to call it the unit -sphere or simply the -sphere for brevity. In terms of the standard norm, the -sphere is defined as : S^n = \left\ , and an -sphere of radius can be defined as : S^n(r) = \left\ . The dimension of -sphere is , and must not be confused with the dimension of the Euclidean space in which it is naturally embedded. An -sphere is the surface or boundary of an -dimensional ball. In particular: *the pair of points at the ends of a (one-dimensional) line segment is a 0-sphere, *a circle, which i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-slit Interferometric Equation
Quantum mechanics was first applied to optics, and interference in particular, by Paul Dirac. Richard Feynman, in his Lectures on Physics, uses Dirac's notation to describe thought experiments on double-slit interference of electrons. Feynman's approach was extended to -slit interferometers for either single-photon illumination, or narrow-linewidth laser illumination, that is, illumination by indistinguishable photons, by Frank Duarte. The -slit interferometer was first applied in the generation and measurement of complex interference patterns. In this article the generalized -slit interferometric equation, derived via Dirac's notation, is described. Although originally derived to reproduce and predict -slit interferograms, this equation also has applications to other areas of optics. Probability amplitudes and the '-slit interferometric equation In this approach the probability amplitude for the propagation of a photon from a source to an interference plane , via an array o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-slit Interferometer
The ''N''-slit interferometer is an extension of the double-slit experiment, double-slit interferometer also known as Young's double-slit interferometer. One of the first known uses of ''N''-slit arrays in optics was illustrated by Isaac Newton, Newton. In the first part of the twentieth century, Albert Abraham Michelson, Michelson described various cases of ''N''-slit diffraction. Richard Feynman, Feynman described thought experiments the explored two-slit quantum interference of electrons, using Braket notation, Dirac's notation. This approach was extended to ''N''-slit interferometers, by F. J. Duarte, Duarte and colleagues in 1989,F. J. Duarte and D. J. Paine, Quantum mechanical description of ''N''-slit interference phenomena, in ''Proceedings of the International Conference on Lasers '88'', R. C. Sze and F. J. Duarte (Eds.) (STS, McLean, Va, 1989) pp. 42–47. using narrow-linewidth laser illumination, that is, illumination by indistinguishable photons. The first application ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-skeleton
In mathematics, particularly in algebraic topology, the of a topological space presented as a simplicial complex (resp. CW complex) refers to the subspace that is the union of the simplices of (resp. cells of ) of dimensions In other words, given an inductive definition of a complex, the is obtained by stopping at the . These subspaces increase with . The is a discrete space, and the a topological graph. The skeletons of a space are used in obstruction theory, to construct spectral sequences by means of filtrations, and generally to make inductive arguments. They are particularly important when has infinite dimension, in the sense that the do not become constant as In geometry In geometry, a of P (functionally represented as skel''k''(''P'')) consists of all elements of dimension up to ''k''. For example: : skel0(cube) = 8 vertices : skel1(cube) = 8 vertices, 12 edges : skel2(cube) = 8 vertices, 12 edges, 6 square faces For simplicial sets The above def ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-player Game
In game theory, an ''n''-player game is a game which is well defined for any number of players. This is usually used in contrast to standard 2-player games that are only specified for two players. In defining ''n''-player games, game theorists usually provide a definition that allow for any (finite) number of players. The limiting case of n \to \infty is the subject of mean field game theory. Changing games from 2-player games to ''n''-player games entails some concerns. For instance, the Prisoner's dilemma is a 2-player game. One might define an ''n''-player Prisoner's Dilemma where a single defection results everyone else getting the sucker's payoff. Alternatively, it might take certain amount of defection before the cooperators receive the sucker's payoff. (One example of an ''n''-player Prisoner's Dilemma is the Diner's dilemma In game theory, the unscrupulous diner's dilemma (or just diner's dilemma) is an ''n''-player prisoner's dilemma. The situation imagined is that severa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-monoid
In category theory, a (strict) ''n''-monoid is an ''n''-category with only one 0-cell. In particular, a 1-monoid is a monoid In abstract algebra, a branch of mathematics, a monoid is a set equipped with an associative binary operation and an identity element. For example, the nonnegative integers with addition form a monoid, the identity element being 0. Monoids ... and a 2-monoid is a strict monoidal category. References * Further reading * {{categorytheory-stub Higher category theory ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-group (category Theory)
In mathematics, an ''n''-group, or ''n''-dimensional higher group, is a special kind of ''n''-category that generalises the concept of group to higher-dimensional algebra. Here, n may be any natural number or infinity. The thesis of Alexander Grothendieck's student Hoàng Xuân Sính was an in-depth study of 2-groups under the moniker 'gr-category'. The general definition of n-group is a matter of ongoing research. However, it is expected that every topological space will have a ''homotopy n-group'' at every point, which will encapsulate the Postnikov tower of the space up to the homotopy group \pi_n, or the entire Postnikov tower for n=\infty. Examples Eilenberg-Maclane spaces One of the principal examples of higher groups come from the homotopy types of Eilenberg–MacLane spaces K(A,n) since they are the fundamental building blocks for constructing higher groups, and homotopy types in general. For instance, every group G can be turned into an Eilenberg-Maclane space K ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-gram
In the fields of computational linguistics and probability, an ''n''-gram (sometimes also called Q-gram) is a contiguous sequence of ''n'' items from a given sample of text or speech. The items can be phonemes, syllables, letters, words or base pairs according to the application. The ''n''-grams typically are collected from a text or speech corpus. When the items are words, -grams may also be called ''shingles''. Using Latin numerical prefixes, an ''n''-gram of size 1 is referred to as a "unigram"; size 2 is a "bigram" (or, less commonly, a "digram"); size 3 is a "trigram". English cardinal numbers are sometimes used, e.g., "four-gram", "five-gram", and so on. In computational biology, a polymer or oligomer of a known size is called a ''k''-mer instead of an ''n''-gram, with specific names using Greek numerical prefixes such as "monomer", "dimer", "trimer", "tetramer", "pentamer", etc., or English cardinal numbers, "one-mer", "two-mer", "three-mer", etc. Applications ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-flake
An ''n''-flake, polyflake, or Sierpinski ''n''-gon, is a fractal constructed starting from an ''n''-gon. This ''n''-gon is replaced by a flake of smaller ''n''-gons, such that the scaled polygons are placed at the vertices, and sometimes in the center. This process is repeated recursively to result in the fractal. Typically, there is also the restriction that the ''n''-gons must touch yet not overlap. In two dimensions The most common variety of ''n''-flake is two-dimensional (in terms of its topological dimension) and is formed of polygons. The four most common special cases are formed with triangles, squares, pentagons, and hexagons, but it can be extended to any polygon. Its boundary is the von Koch curve of varying types – depending on the ''n''-gon – and infinitely many Koch curves are contained within. The fractals occupy zero area yet have an infinite perimeter. The formula of the scale factor ''r'' for any ''n''-flake is: :r = \frac where cosine is evaluate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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