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wedge photometer nursanj-e gove-yi Fr.: photomètre à coin A photometer in which an → absorbing wedge is inserted in the brighter of two beams until the flux densities of the two light sources are equal. → wedge; → photometer. |
week hafté (#) Fr.: semaine A division of time containing 7 successive days, which is completely independent of the month or the year. Unlike the month and the year, the week is an artificial unit of time, lacking an equivalent astronomical period. M.E. weke; O.E. wice, cf. O.N. vika, M.Du. weke, O.H.G. wecha, Ger. Woche, akin to L. vicis "turn, change." Hafté "week, hebdomad," from haft "seven" → hepta-. |
Weierstrass approximation theorem farbin-e nazdineš-e Weierstrass Fr.: théorème d'approximation de Weierstrass If a function φ(x) is continuous on a closed interval [a,b], then for every ε > 0 there exists a polynomial P(x) such that |f(x) - P(x)| <ε, for every x in the interval. After German mathematician Karl Wilhelm Theodor Weierstrass (1815-1897); → approximation; → theorem. |
Weierstrass M test âzmun-e M Weierstrass Fr.: Weierstrass A test for uniform convergence of a sequence of functions. If there exists a series of numbers Σ M_{i} (summed from n = 1 to ∞), in which M_{i}≥ Σ |u_{i}(x)| for all x in the interval [a, b] and Σ M_{i} is convergent, the series u_{i}(x) will be uniformly convergent in that interval. → Weierstrass approximation theorem; M referring to
→ majorant; → test. |
weight vazn (#) Fr.: poids 1) The force of attraction of the Earth on a given mass.
→ molecular weight; → weightlessness. M.E., from O.E. gewiht, cf. O.N. vætt, O.Fris. wicht, M.Du. gewicht, Ger. Gewicht. Vazn, loan from Ar. wazn. |
weight concentration dabzeš-e vazni Fr.: concentration en poids of a gas included in the composition of a → gas mixture, the ratio of mass of this gas to the mass of the whole mixture. Same as → weight fraction and → weight-fraction concentration. → weight; → concentration. |
weight fraction barxe-ye vazni Fr.: fraction en poids Same as → weight concentration. |
weight of a tensor density vazn-e cagâli-ye tânsor Fr.: poids d'une densité de tenseur A constant the value of which is characteristic for any given → tensor density. |
weight-fraction concentration barxe-ye vazni-ye dabzeš Fr.: concentration en poids Same as → weight concentration. → weight; → fraction; → concentration. |
weighted mean miyângin-e vazni (#) Fr.: moyenne pondérée An mean which is obtained by combining different numbers according to the relative importance of each. |
weightlessness bivazni (#) Fr.: apesanteur The phenomenon experienced by a body when there is no force of reaction on it. This happens when the body is in → free fall in a → gravitational field or when the net force on it is zero. From → weight + -less suffix meaning "without" + -ness a suffix of quality or state. |
Weizsacker formula disul-e Weizsäcker Fr.: formule de Weizsäcker A → semiempirical → equation
which describes the → binding energy
of the → atomic nucleus. It is essentially a nuclear mass formula
that provides the total binding energy per → nucleon as the sum
of five terms: Named after Carl Friedrich von Weizäcker (1912-2007), German physicist, who derived the formula in 1935, Z. für Physik 96, 431; → formula. |
well 1) xoš, xub; 2) câh Fr.: 1) In a good or satisfactory manner; thoroughly, carefully, or soundly. 1) M.E., from O.E. wel(l) (cognates Du. wel, Ger. wohl). 1) Xoš "good, well, sweet, fair, lovely," probably related to hu-
"good, well," → eu-.
Xub, ultimately from Av. huuāpah-
"doing good work," → operate. |
well-formed formula (wff) disul-e xošdisé (wff) Fr.: formule bien formée (FBF) A string of → symbols from the alphabet of the → formal language that conforms to the grammar of the formal language. → closed wff, → open wff. |
well-ordered set hangard-e xoš-râyé Fr.: ensemble bien ordonné A set in which every → nonempty → subset has a minimum element. |
Werner band bând-e Werner Fr.: bande de Werner A sequence of → permitted transitions in the → ultraviolet from an → excited state (C) of the → molecular hydrogen (H_{2}) to the electronic → ground state, with ΔE > 12.3 eV and λ ranging from 1160 Å to 1250 Å. When a hydrogen molecule absorbs such a photon, it undergoes a transition from the ground electronic state to the excited state (C). The following rapid → decay creates an → absorption band in that wavelength range. See also → Lyman band; → Lyman-Werner photon. Named after the Danish physicist Sven Theodor Werner (1898-1984), who discovered the band (S. Werner, 1926, Proc. R. Soc. London Ser. A, 113, 107); → band. |
west bâxtar (#) Fr.: ouest The direction 90° to the left or 270° to the right of → north. M.E., O.E. "west" "in or toward the west;" cf. O.N. vestr, O.Fris., M.Du., Du. west, Ger. West; PIE base *wes- (Gk. hesperos, L. vesper "evening, west"). Bâxtar "west;" Mid.Pers. apâxtar "north;" Av. apāxtar "northern." |
western bâxtari (#) Fr.: (de l') ouest, occidental Lying toward or situated in the west. → greatest western elongation. Adjective from → west. |
western elongation derâzeš-e bâxtari Fr.: élongation ouest The position of a planet when it is visible in the eastern sky before dawn. → western; → elongation. |
wet xis (#) Fr.: mouillé Consisting of, containing, covered or soaked with water or some other liquid. O.E. wæt "moist, liquid," related to O.Frisian wēt, O.N. vātr, O.E. wæter "water." Xis, xês "wet, moist," related to pašang, pašangidan "sprinkle," ultimately from Proto-Ir. *haic- "to pour (out), moisten;" cf. Av. haēc- "to pour (out); to irrigate;" Khotanese häs- "to wet, besprinkle;" Sogd. šync "to pour" (Cheung 2007). |
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