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N. G. Kuznetsov Naval Academy Alumni
N is the fourteenth letter of the English alphabet. N or n may also refer to: Mathematics * \mathbb or N, the set of natural numbers * N, the field norm * N for ''nullae'', a rare Roman numeral for zero * n, the size of a statistical sample Science * ATC code N ''Nervous system'', a section of the Anatomical Therapeutic Chemical Classification System * Haplogroup N (mtDNA), a human mitochondrial DNA haplogroup * Haplogroup N (Y-DNA), a human Y-chromosome DNA haplogroup * N band, an atmospheric transmission window in the mid-infrared centred on 10 micrometres * N ray, a hypothesized form of radiation, found to be illusory *N., abbreviation of the Latin word ''nervus'' meaning nerve, used in anatomy, e.g. N. vagus Quantities and units * N for Newton (unit), the SI derived unit of force * N or F_n, a normal force in mechanics * Nitrogen, symbol N, a chemical element * N or Asn, the symbol for the common natural amino acid asparagine * N, the Normality (chemistry) or c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Number
In mathematics, the natural numbers are the numbers 0, 1, 2, 3, and so on, possibly excluding 0. Some start counting with 0, defining the natural numbers as the non-negative integers , while others start with 1, defining them as the positive integers Some authors acknowledge both definitions whenever convenient. Sometimes, the whole numbers are the natural numbers as well as zero. In other cases, the ''whole numbers'' refer to all of the integers, including negative integers. The counting numbers are another term for the natural numbers, particularly in primary education, and are ambiguous as well although typically start at 1. The natural numbers are used for counting things, like "there are ''six'' coins on the table", in which case they are called ''cardinal numbers''. They are also used to put things in order, like "this is the ''third'' largest city in the country", which are called ''ordinal numbers''. Natural numbers are also used as labels, like Number (sports), jersey ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brillouin Zone
In mathematics and solid state physics, the first Brillouin zone (named after Léon Brillouin) is a uniquely defined primitive cell in reciprocal space Reciprocal lattice is a concept associated with solids with translational symmetry which plays a major role in many areas such as X-ray diffraction, X-ray and Electron diffraction, electron diffraction as well as the Electronic band structure, e .... In the same way the Bravais lattice is divided up into Wigner–Seitz cells in the real lattice, the reciprocal lattice is broken up into Brillouin zones. The boundaries of this cell are given by planes related to points on the reciprocal lattice. The importance of the Brillouin zone stems from the description of waves in a periodic medium given by Bloch's theorem, in which it is found that the solutions can be completely characterized by their behavior in a single Brillouin zone. The first Brillouin zone is the locus of points in reciprocal space that are closer to the or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tokyo Metro Namboku Line
The is a subway line owned and operated by Tokyo Metro in Tokyo, Japan. The line runs between Meguro in Shinagawa and Akabane-Iwabuchi in Kita. The Namboku Line was referred to as Line 7 during the planning stages, thus the seldom-used official name is . On maps, diagrams and signboards, the line is shown using the color emerald (previously coded "teal"), and its stations are given numbers using the letter "N". Overview Trains run through onto the Tokyu Meguro Line for and the Saitama Railway's Saitama Rapid Railway Line (which is essentially a separately-owned extension of the Namboku Line) for . The right-of-way and stations between and Meguro are shared with the Toei Mita Line – a unique situation on the Tokyo subway where both operators share common infrastructure. Under an agreement between Tokyo Metro and the Tokyo Metropolitan Government, the fare for this section is calculated on the Toei fare system for passengers traveling to stations on the Mita Line pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N (Los Angeles Railway)
N was a streetcar line in Los Angeles, California. It was operated by the Los Angeles Railway from 1920 to 1950. The line ran from Spring and 2nd Streets to 8th Street and Western Avenue, by way of Spring Street, 9th Street, Vermont Avenue, and 8th Street. History The Ninth Street Line was built by the Los Angeles Railway in 1895 and ran via Spring Street, 9th Street, and Park View to a junction with the Lincoln Heights Line at 10th and Hoover Streets. From there both routes ran along West 10th Street to a terminus at Vermont Avenue. Circa 1911, the Park View section was eliminated and the route was extended along 9th Street, Vermont, and 8th Street to a loop at Western Avenue. In 1920, the line was rerouted, operating from 8th and Harvard via 8th; Vermont; 9th; Spring; 2nd; Traction Way; 3rd; and Santa Fe to 2nd, terminating at the Los Angeles Atchison, Topeka and Santa Fe Railway station. It was given the letter designation N in 1921. Tracks were laid on a newly-rebui ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N Judah
The N Judah is a hybrid light rail/streetcar line of the Muni Metro system in San Francisco, California. The line is named after Judah Street that it runs along for much of its length, named after railroad engineer Theodore Judah. It links downtown San Francisco to the Cole Valley, San Francisco, California, Cole Valley and Sunset District, San Francisco, California, Sunset neighborhoods. The line provides rail access to Golden Gate Park. It is the busiest line in the Muni Metro system, serving an average of 41,439 weekday passengers in 2013. It was one of San Francisco's streetcar lines, beginning operation in 1928, and was partially converted to modern light-rail operation with the opening of the Muni Metro system in 1980. While many streetcar lines were converted to bus lines after World War II, the N Judah remained a streetcar line due to its use of the Sunset Tunnel. Route description The line runs from the Caltrain depot in the Mission Bay, San Francisco, California, Mis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N (New York City Subway Service)
The N Broadway Express is a rapid transit service in the B Division of the New York City Subway. Its route emblem, or "bullet," is colored , since it uses the BMT Broadway Line in Manhattan. The N operates 24 hours daily between Ditmars Boulevard in Astoria, Queens, and Stillwell Avenue in Coney Island, Brooklyn; limited rush hour service originates and terminates at 96th Street on the Upper East Side of Manhattan instead of Ditmars Boulevard. Weekday daytime service makes all stops in Queens and express stops in Manhattan, and in Brooklyn (between Atlantic Avenue and 59th Street), bypasses DeKalb Avenue and operates via the Manhattan Bridge, bypassing the Financial District of Lower Manhattan. Weekend daytime service is the same as weekday daytime service, except trains make all stops in Manhattan between 34th and Canal Streets. Overnight service makes all stops along the full route, serves the Financial District and uses the Montague Street Tunnel to travel betw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amine
In chemistry, amines (, ) are organic compounds that contain carbon-nitrogen bonds. Amines are formed when one or more hydrogen atoms in ammonia are replaced by alkyl or aryl groups. The nitrogen atom in an amine possesses a lone pair of electrons. Amines can also exist as hetero cyclic compounds. Aniline is the simplest aromatic amine, consisting of a benzene ring bonded to an amino group. Amines are classified into three types: primary (1°), secondary (2°), and tertiary (3°) amines. Primary amines (1°) contain one alkyl or aryl substituent and have the general formula RNH2. Secondary amines (2°) have two alkyl or aryl groups attached to the nitrogen atom, with the general formula R2NH. Tertiary amines (3°) contain three substituent groups bonded to the nitrogen atom, and are represented by the formula R3N. The functional group present in primary amines is called the amino group. Classification of amines Amines can be classified according to the nature and number o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Open-chain Compound
In chemistry, an open-chain compound (or open chain compound) or acyclic compound (Greek prefix ''α'' 'without' and ''κύκλος'' 'cycle') is a compound with a linear structure, rather than a Cyclic compound, cyclic one. An open-chain compound having no side groups 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 compound, cyclic. 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 compound, aliphatic. Typically in biochemistr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coordination Number
In chemistry, crystallography, and materials science, the coordination number, also called ligancy, of a central atom in a molecule or crystal is the number of atoms, molecules or ions bonded to it. The ion/molecule/atom surrounding the central ion/molecule/atom is called a ligand. This number is determined somewhat differently for molecules than for crystals. For molecules and polyatomic ions the coordination number of an atom is determined by simply counting the other atoms to which it is bonded (by either single or multiple bonds). For example, [Cr(NH3)2Cl2Br2]− has Cr3+ as its central cation, which has a coordination number of 6 and is described as ''hexacoordinate''. The common coordination numbers are 4, 6 and 8. Molecules, polyatomic ions and coordination complexes In chemistry, coordination number, defined originally in 1893 by Alfred Werner, is the total number of neighbors of a central atom in a molecule or ion. The concept is most commonly applied to coordination ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amount Of Substance
In chemistry, the amount of substance (symbol ) in a given sample of matter is defined as a ratio () between the particle number, number of elementary entities () and the Avogadro constant (). The unit of amount of substance in the International System of Units is the Mole (unit), mole (symbol: mol), a SI base unit, base unit. p. 134 Since 2019, the mole has been defined such that the value of the Avogadro constant is exactly , defining a macroscopic unit convenient for use in laboratory-scale chemistry. The elementary entities are usually molecules, atoms, ions, or Ion pair, ion pairs of a specified kind. The particular chemical substance, substance sampled may be specified using a subscript or in parentheses, e.g., the amount of sodium chloride (NaCl) could be denoted as or . Sometimes, the amount of substance is referred to as the chemical amount or, informally, as the "number of moles" in a given sample of matter. The amount of substance in a sample can be calculated from mea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron Density
Electron density or electronic density is the measure of the probability of an electron being present at an infinitesimal element of space surrounding any given point. It is a scalar quantity depending upon three spatial variables and is typically denoted as either \rho(\textbf r) or n(\textbf r). The density is determined, through definition, by the normalised N-electron wavefunction which itself depends upon 4N variables (3N spatial and N Spin (physics), spin coordinates). Conversely, the density determines the wave function modulo up to a phase factor, providing the formal foundation of density functional theory. According to quantum mechanics, due to the uncertainty principle on an atomic scale the exact location of an electron cannot be predicted, only the probability of its being at a given position; therefore electrons in atoms and molecules act as if they are "smeared out" in space. For one-electron systems, the electron density at any point is proportional to the square ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Principal Quantum Number
In quantum mechanics, the principal quantum number (''n'') of an electron in an atom indicates which electron shell or energy level it is in. Its values are natural numbers (1, 2, 3, ...). Hydrogen and Helium, at their lowest energies, have just one electron shell. Lithium through Neon (see periodic table) have two shells: two electrons in the first shell, and up to 8 in the second shell. Larger atoms have more shells. The principal quantum number is one of four quantum numbers assigned to each electron in an atom to describe the quantum state of the electron. The other quantum numbers for bound electrons are the total angular momentum of the orbit ''ℓ'', the angular momentum in the z direction ''ℓz'', and the spin of the electron ''s''. Overview and history As ''n'' increases, the electron is also at a higher energy and is, therefore, less tightly bound to the nucleus. For higher ''n'', the electron is farther from the nucleus, on average. For each value of ''n'', th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
