Fr.: cœur de réacteur
Fr.: facteur de réflexion
The ratio of total flux that is reflected from a surface to the incident flux. Also called reflectance, reflectivity.
To alter the course of a wave of light, sound, etc. when the wave crosses the boundary between this medium and another through which it travels at a different speed.
From L. refractus, p.p. of refringere, → refraction.
Verb of šekast, → refraction.
partow-e šekasté (#)
Fr.: rayon réfracté
A → light ray that undergoes a change of velocity and direction, as a result of interaction with the material medium in which it travels.
Fr.: réfraction; à réfraction
manšur-e šekastgar (#)
Fr.: prisme réfractant
A prism that is used as a dispersing element in a spectrograph.
teleskop-e šekasti (#), durbin-e ~ (#)
Fr.: lunette astronomique
A telescope in which an image is formed by the refraction of light through a lens or lens system.
1) Optics: The change of direction which a beam of light undergoes as it
enters a medium of different → refractive index.
From L.L. refractionem (nominative refractio) "a breaking up," from L. refractus, p.p. of refringere "to break up," from re- "back" + combining form of frangere "to break," from PIE base *bhreg- "to break" (cf. Goth. brikan, O.E. brecan "to break;" Lith. brasketi "crash, crack").
Šekast, past stem of šekastan "to break, split;" Mid.Pers. škastan "to break;" Av. scind-, scand "to beak, cleave;" Proto-Iranian *skand- "to break, cleave;" PIE sken- "to cut off."
Fr.: indice de réfraction
Of any optical medium, the ratio of the → speed of light in vacuum (c) to that in the medium (v): n = c/v. The refractive index for vacuum, by definition, is 1. The refractive index of air is 1.00029 at standard temperature (25 °C) and pressure (1 atm). The refractive index of a medium depends on the wavelength of refracted wave. With light waves, n increases as the wavelength decreases. → Snell's law can be used to derive n. Same as → index of refraction.
Same as → refracting telescope.
Agent noun of refract, → refraction.
From refract, → refraction + adj. suffix -ory.
Sarkeš "refractory, disobedient, rebellious, stubborn,"
literally "withdrw, remove head," from sar
"head" (variants soru, sorun "horn,"
karnâ "a trumpet-like wind instrument," variant sornâ "a wind instrument;"
Mid.Pers. sar "head," sru "horn;" Av. sarah- "head,"
srū- "horn, nail;" cf. Skt. śiras- "head, chief;"
Gk. kara "head," karena "head, top," keras "horn;"
L. cornu "horn," cerebrum "brain;"
P.Gmc. *khurnaz (Ger. Horn, Du. horen;
cognate with E. horn, as above, from PIE *ker- "head, horn;"
O.E. horn "horn of an animal," also "wind instrument;"
E. horn); PIE base *ker-
"head, horn, top, summit")
+ keš present stem of kešidan, kašidan
"to draw; withdraw, remove" (dialectal Yaqnavi xaš "to draw," Qomi xaš
"streak, stria, mark," Lori kerr "line;"
Av. karš- "to draw; to plow," karša-
"furrow;" Proto-Iranian *kerš-/*xrah- "to draw, plow;"
cf. Skt. kars-, kársati "to pull, drag, plow;"
Gk. pelo, pelomai "to move, to bustle;" PIE base kwels-
relative refractive index
dišan-e šekasti-ye bâzâni
Fr.: indice de réfraction relatif
The ratio of the sine of the angle of incidence to the sine of the angle of refraction for a ray passing out of one of the media into the other.
Fr.: réacteur de recherche
A nuclear reactor designed for radionuclide production, materials testing, and training.
Fr.: réaction résonnante
A nuclear reaction whose probability is enhanced at an energy corresponding to an energy level of one of the nuclei. → resonance capture.
Fr.: facteur d'échelle
A number which scales, or multiplies, some quantity. In the equation
y = Cx, C is the scale factor for x. C is also the
coefficient of x, and may be called the constant of proportionality of
y to x.
bâšâ-ye dâneši, ~ dânešik
Fr.: fait scientifique
An agreement by competent observers of a series of observations of the same phenomena. From time to time scientific facts are revised by additional data (G. Smooth, Lawrence Berkeley Lab website).
screened Coulomb interaction
andaržireš-e bâparde-ye Coulomb
Fr.: interaction de Coulomb écrantée
Fr.: deuxième contact
The beginning of the total phase of a solar eclipse when the leading edge of the Moon touches the eastern edge of the Sun completely obscuring the Sun.
Fr.: fraction simple
Fr.: soustraction de ciel
The act or instance of removing the contribution of non-related, intervening foreground light to the object.