setâre-ye šâmgâh (#)
Fr.: étoile du soir
An → evening star, especially the planet Venus in its appearance as the evening star.
M.E., from L., from Gk. hesperos "evening, western;" → west.
Setâre-ye šâmgâh "evening star," from setâré→ star + šâmgâh "evening," from šâm "evening, evening meal" + gâh "time." The first component, šâm, from Mid.Pers. šâm "evening meal, supper," from Av. xšāfnya- "evening meal," from Av. xšap-, xšapā-, xšapan-, xšafn- "night" (O.Pers. xšap- "night," Mid.Pers. šap, Mod.Pers. šab "night"); cf. Skt. ksap- "nigh, darkness;" Hittite ispant- "night." The second component gâh "time," Mid.Pers. gâh, gâs "time," O.Pers. gāθu-, Av. gātav-, gātu- "place, throne, spot;" cf. Skt. gâtu- "going, motion; free space for moving; place of abode;" PIE *gwem- "to go, come."
Fr.: collaboration HESS
Fr.: diagramme de Hess
Named after R. Hess who originated it in 1924: "Die Verteilungsfunktion der absoluten Helligkeiten in ihrer Abhängigkeit vom Spektrum". Probleme der Astronomie. Festschrift fur Hugo v. Seeliger. Springer, Berlin. p. 265; → diagram.
Prefix denoting "other, different."
From Gk. heteros "the other (of two), another, different."
Degar "another, other;" from Mid.Pers. dit, ditikar "the other, the second;" O.Pers. duvitiya- "second," Av. daibitya-, bitya- "second;" Skt. dvitiya- "second," PIE *duitiio- "second."
1) Denoting a device or method of combining two
→ electromagnetic waves
of different → frequency
(a locally generated wave and an incoming wave)
in a → nonlinear device
to produce two frequencies which are
equal to the → sum and
→ difference of the first two.
The phenomenon is the counterpart of → beats
produced by → sound waves.
For example, heterodyning a 100-kHz and a 10-kHz signal will
produce a 110-KHz and a 90-kHz signal.
See also → homodyne.
Fr.: interféromètre hétérodyne
An → interferometer using a technique that involves introducing a small → frequency shift between the optical frequencies of the two interfering light beams. This results in an intensity modulation at the → beat frequency of the two beams for any given point of the → interference pattern. A convenient way of introducing such a frequency shift is by means of an acousto-optic modulator.
girande-ye heterodini (#)
Fr.: récepteur hétérodyne
Fr.: technique hétérodyne
Noun from → heterogeneous.
1) Composed of parts of different kinds; having widely dissimilar elements or constituents.
See also → homogeneous,
Methodology, Math.: Pertaining to a method of analyzing outcome through comparison to previously recognized patterns in the absence of an → algorithm for formal proof.
From L. heuristicus (from Gk. heuretikos "inventive," related to heuriskein "to find," from heur-) + -isticus, → -ic.
šešbar (#), šešguš (#)
A six-sided → polygon.
Fr.: étoile HgMn
A → chemically peculiar star of late → B-types. The most distinctive features of HgMn stars are extreme atmospheric overabundance of Hg (up to 5 dex) and of Mn (up to 3 dex). The origin of abundance anomalies observed in late B-type stars with HgMn peculiarity is still poorly understood. More than two thirds of the HgMn stars are known to belong to spectroscopic binaries with a preference of orbital periods ranging from 3 to 20 days (Hurbig et al., 2012, arXiv:1208.2910).
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 arcsec2 and satisfies an isolation criterion.
Being out of sight; concealed.
From M.E., from O.E. hydan, from W.Gmc. *khuthjanan, from PIE *keudh- (cf. Gk. keuthein "to hide, conceal"), from base *(s)keu- "to cover, conceal."
Penhân "hidden," from Mid.Pers. pad nihân, from pad "to, at, for, in" (from O.Pers. paity; Av. paiti "to, toward, in, at;" cf. Skt. práti; Gk. poti) + nihân "concealment, secrecy, hiding place" (Mod.Pers. nahân), from Proto-Iranian *ni-dāna-, from ni- "down; into," → ni- (PIE), + dā- "to put; to establish; to give" (dadâiti "he gives;" cf. Skt. dadâti "he gives;" Gk. didomi "I give;" L. do "I give;" PIE base *do- "to give").
jerm-e penhân (#)
Fr.: masse cachée
Fr.: variable caché
A theory based on the hypothesis that the discrepancies with respect to classical reality found in → quantum mechanics stem from our lack of knowledge about the observed system (→ EPR paradox). According to this hypothesis, the system should be described by additional quantum parameters, of still unknown nature, but different from position, velocity, spin, etc. The hidden variable theory has been ruled out by the violation of → Bell's inequality for all theories with local property, as suggested by the → Aspect experiment.
xušé bandi-ye pâygâni
Fr.: groupement hiérarchique
A model in which a system of self-gravitating particles will gradually aggregate into larger and larger gravitationally bound groups and clusters.