<< < "no abe acc act aff ama ani ant aps ast atm aut bar bic Boh bou cal car cel che cla col com com Com con con con con con con con con con con con con Cor cor cot cul de- dec dem des dif dil dir dis dom dyn Edd ele ele emi equ Eve exc exp fac fin for fre fuz gen Glo gra gra Ham hel hor hyd ign inc inf Inf int Int int ion irr jum Lag lea lig lin Lor Lyo mag mat met min Mon moo NaC neg New New non non non nul obs one opt Ori oxi par per per phl pho pla Pla pol pos pre pro pro pse qua rad rad rea rec reg rel res ret rot Ryd sci sec sec seq sim Sod sor spe sta ste sto sub sup syn the Tho Tor tra tru und vec vio wav Wil zir > >>
heliocentric gravitational constant pâyâ-ye gerâneši-ye hur-markazi Fr.: constante gravitationnelle héliocentrique A parameter representing the product of the → gravitational constant by the → solar mass. It is 13.27 x 10^{19} m^{3} s^{-2}. → heliocentric; → gravitational; → constant. |
helium-argon calibration kabizeš-e heliyom-ârgon Fr.: calibration hélium-argon A wavelength calibration of astronomical spectra using a helium-argon light source. → helium; → argon; → calibration. |
helium-argon lamp lâmp-e heliyom-ârgon (#) Fr.: lampe hélium-argon A comparison light source containing the known spectral lines of helium and Argon. |
heptagon haftbar (#), haftguš (#) Fr.: heptagone |
Hermitian conjugate hamyuq-e Hermiti Fr.: conjugé hermitien Math.: The Hermitian conjugate of an m by n matrix A is the n by m matrix A^{*} obtained from A by taking the → transpose and then taking the complex conjugate of each entry. Also called adjoint matrix, conjugate transpose. → Hermitian operator. Hermitian, named in honor of the Fr. mathematician Charles Hermite (1822-1901), who made important contributions to number theory, quadratic forms, invariant theory, orthogonal polynomials, elliptic functions, and algebra. One of his students was Henri Poincaré; → conjugate. |
hertz to meter conversion hâgard-e hertz bé metr Fr.: conversion hertz / mètre → frequency to wavelength conversion. → hertz; → meter; → conversion. |
HESS collaboration hamkâri-ye HESS Fr.: collaboration HESS → High Energy Stereoscopic System (H.E.S.S.). → H.E.S.S.; → collaboration. |
hexagon šešbar (#), šešguš (#) Fr.: hexagone A six-sided → polygon. |
Hickson Compact Group (HCG) goruh-e hampak-e Hickson Fr.: groupe compact de Hickson A list of 100 compact groups of galaxies that were identified by a systematic search of the → Palomar Observatory Sky Survey red prints. Each group contains four or more galaxies, has an estimated mean surface brightness brighter than 26.0 magnitude per arcsec^{2} and satisfies an isolation criterion. |
hierarchical structure formation diseš-e sâxtâr-e pâygâni Fr.: formation de structures hiérarchiques A cosmological → structure formation model in which the smallest gravitationally bound structures (→ quasars and galaxies) form first, followed by → groups, → galaxy clusters, and → superclusters of galaxies. → hierarchical; → structure; → formation. |
Higgs boson boson-e Higgs (#) Fr.: boson de Higgs A hypothetical, neutral → elementary particle which plays a key role in the → standard model of → particle physics. This massive particle, whose mass is estimated to be about 125 GeV (→ giga → electron-volts) and a zero → spin, carries the → Higgs field. In the current version of the → electroweak theory, → W boson and → Z boson and all the fundamental constituents (→ quarks and → leptons) get their masses by interacting with the Higgs boson. The Higgs boson is produced by the fusion of two → gluons via a triangular loop of virtual top quarks. In the decay process, a loop of virtual top quarks allows the Higgs boson to decay into two photons. The particle's discovery was announced by → CERN in July 2012. Named after the Scottish physicist Peter Ware Higgs (1929-), one of the researchers who theorized the existence of this particle in 1964. In fact three groups of physicists almost simultaneously published their results on this subject: François Englert and Robert Brout in August 1964; Peter Higgs in October 1964; and Gerald Guralnik, Carl Hagen, and Tom Kibble in November 1964; → boson. |
high-excitation blob (HEB) žig-e por-barangizeš Fr.: A rare class of → H II regions in the → Magellanic Clouds. In contrast to the typical H II regions of the Magellanic Clouds, which are extended structures (sizes of several arc minutes corresponding to more than 50 pc, powered by a large number of exciting stars), HEBs are very dense and small regions (~ 4" to 10" in diameter corresponding to ~ 1-3 pc). They have a higher degree of → excitation ([O III] 5007Å /Hβ) with respect to the typical H II regions, and are, in general, heavily affected by local → dust. They are powered by a relatively smaller number of → massive stars. → high; → excitation; → blob. |
high-resolution observation nepâheš-e mehvâgošud Fr.: observation à haute résolution An observation that provides a particularly narrow, peaked image of a point source. → point spread function. → high; → resolution; → observation. |
hole injection daršâneš-e surâx, ~ câlé Fr.: injection de trou The injection of holes in a semiconductor which can be produced by application of a sharp conducting point in contact with an n-type semiconductor. |
holonomic system râžmân-e harudâtik Fr.: système holonomique A material system in which the → constraints can be expressed in the form of an equation relating the coordinates. From Gk. → holo- "whole" + -nomic, related to nomos "law, managing, governing, custom," → -nomy; → system. |
homogeneous linear differential equation hamugeš-e degarsâne-yi-ye xatti hamgen Fr.: équation différentielle linéaire homogène A → linear differential equation if the right-hand member is zero, Q(x) = 0, on interval I. → homogeneous; → linear; → differential; → equation. |
homonuclear molecule molekul-e ham-hasté Fr.: molécule homonucléaire A molecule that is composed of only one type of → chemical element, e.g. the → molecular hydrogen and → ozone. |
horizon ofoq (#) Fr.: horizon 1) An imaginary circle that delimits the sky and the Earth. From O.Fr. orizon, from orizonte, from L. horizontem (nom. horizon), from Gk. horizon kyklos "bounding circle," from horizein "bound, limit, divide, separate," from horos "boundary." Ofoq, from Ar. |
horizon coordinate system râžmân-e hamârâhâ-ye ofoqi Fr.: coordonnées horizontales The coordinate system based on the position of the observer. The horizontal plane is the fundamental plane and the coordinates are → altitude and → azimuth. → horizon; → coordinate; → system. |
horizon problem parâse-ye ofoq Fr.: problème de l'horizon A problem with the standard cosmological model of the Big Bang related to the observational fact that regions of the Universe that are separated by vast distances nevertheless have nearly identical properties such as temperature. This contradicts the fact that light moves with a finite speed and, as a result, certain events which occur in the Universe are completely independent of each other. Inflationary cosmology offers a possible solution. |
<< < "no abe acc act aff ama ani ant aps ast atm aut bar bic Boh bou cal car cel che cla col com com Com con con con con con con con con con con con con Cor cor cot cul de- dec dem des dif dil dir dis dom dyn Edd ele ele emi equ Eve exc exp fac fin for fre fuz gen Glo gra gra Ham hel hor hyd ign inc inf Inf int Int int ion irr jum Lag lea lig lin Lor Lyo mag mat met min Mon moo NaC neg New New non non non nul obs one opt Ori oxi par per per phl pho pla Pla pol pos pre pro pro pse qua rad rad rea rec reg rel res ret rot Ryd sci sec sec seq sim Sod sor spe sta ste sto sub sup syn the Tho Tor tra tru und vec vio wav Wil zir > >>