An Etymological Dictionary of Astronomy and Astrophysics
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فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 30 Search : temperature
spin temperature
  دمای ِ اسپین   
damâ-ye espin

Fr.: température de spin   

The → excitation temperature of the → hyperfine structure levels of the → neutral hydrogen21-centimeter line.

spin; → temperature.

standard temperature and pressure (STP)
  دما و فشار ِ استانده   
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.
2) Chemistry: Temperature of 273.15 K (0 °C) and pressure of 105  → pascal (Pa)s (1 → bar). International Union of Pure and Applied Chemistry (IUPAC) recommends that the former use of the pressure of 1 atm as standard pressure (equivalent to 1.01325 × 105 Pa) should be discontinued.

standard; → temperature; → pressure.

superadiabatic temperature gradient
  زینه‌ی ِ دمای ِ اَبَر-بی‌دررو   
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
  دما‌ی ِ رویه، ~ رویه‌ای   
damâ-ye ruyé, ~ ruye-yi

Fr.: température de surface   

1) For a star, same as → effective temperature.
2) Meteo.: The air temperature at or near the earth's surface.

surface; → temperature.

temperature
  دما   
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
  ناهمسانگردی ِ دما، نا-ایزوگردی ِ ~   
nâhamsângardi-ye damâ (#), nâ-izogardi-ye ~

Fr.: anisotropie de température   

Cosmology: Minute temperature variations of the cosmic microwave background radiation.

temperature; → anisotropy.

temperature gradient
  زینه‌ی ِ دما   
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
  واگردانی ِ دما   
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
  دمای ِ گرماتوانیک   
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
  دمای ِ ویریال   
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)kTvir, 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 Tvir = (1/3)(GM/kR).

virial; → temperature.

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