spin temperature damâ-ye espin Fr.: température de spin The → excitation temperature of the → hyperfine structure levels of the → neutral hydrogen→ 21-centimeter line. → spin; → temperature. |
standard temperature and pressure (STP) damâ o fešâr-e estândé Fr.: conditions normales de température et de pression 1) The most commonly used definition is temperature of 273.15 K (0 °C) and
pressure of 1 → atmosphere. → standard; → temperature; → pressure. |
superadiabatic temperature gradient zine-ye damâ-ye abar-bidarrow Fr.: gradient de température super-adiabatique A condition in which there is an excess of the actual temperature gradient over the → adiabatic temperature gradient corresponding to the same pressure gradient. A region with superadiabatic temperature gradient is convectively unstable. → Hayashi forbidden zone. → super-; → adiabatic; → temperature; → gradient. |
surface temperature damâ-ye ruyé, ~ ruye-yi Fr.: température de surface 1) For a star, same as → effective temperature. → surface; → temperature. |
temperature damâ (#) Fr.: température A physical quantity characterizing the mean random motion of molecules in a physical body. In other words, a measure of the average kinetic energy of the particles of a system. From L. temperatura "a tempering, moderation," from temperatus, p.p. of temperare "to moderate, to mix." Sense of "degree of heat or cold" first recorded 1670 (Boyle), from L. temperatura, used in this sense by Galileo. Damâ, from dam "breath of an owen; bellows; smoke; air," also "moment, time," from Mid./Mod.Pers. damidan "to blow, breathe;" Av. dāδmainya- "blowing up;" cf. Skt. dahm- "to blow," dhámati "blows;" Gk. themeros "austere, dark-looking;" Lith. dumti "to blow;" PIE dhem-/dhemə- "to smoke, to blow." |
temperature anisotropy nâhamsângardi-ye damâ (#), nâ-izogardi-ye ~ Fr.: anisotropie de température Cosmology: Minute temperature variations of the cosmic microwave background radiation. → temperature; → anisotropy. |
temperature gradient zine-ye damâ (#) Fr.: gradient de température A physical quantity that describes the rate of change of temperature with displacement in a given direction from a given reference point. Same as → thermal gradient. → temperature; → gradient. |
temperature inversion vâgardâni-ye damâ Fr.: inversion de température Meteo.: A reversal in the normal temperature decrease, the temperature rising with increased elevation in the atmosphere instead of falling. A layer in which temperature increases with altitude. → temperature; → inversion. |
thermodynamic temperature damâ-ye garmâtavânik Fr.: température thermodynamique A temperature scale, measured in → kelvin (K), that is related to the energy possessed by matter; it was formerly known as → absolute temperature. The zero point on the scale (0 K) is absolute zero. Thermodynamic temperature can be converted to temperature on the → Celsius scale by subtracting 273.15. → thermodynamic; → temperature. |
virial temperature damâ-ye viriyâl Fr.: température du viriel The mean temperature at which a gravitationally → bound system would satisfy the → virial theorem. For a system of mass M and radius R with constant density, the gravitational energy per unit mass is W = GM/R. The kinetic energy per unit mass is E = (3/2)kT_{vir}/μ, where k is → Boltzmann's constant and μ the mean molecular weight. According to the virial theorem, E = W/2, which leads to the virial temperature T_{vir} = (1/3)(GM/kR). → virial; → temperature. |