An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

   Homepage   
   


A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

<< < "no abe acc act aff ama ani ant aps ast atm aut bar bif Boh bou cal car Cen chi Cla col com com Com con con con con con con con con con con con con cor cor Cou cur dec def Den det dif dim dis dis dou E-t edi ele ell ene ero exa exp ext fer Fla fra FU Gam geo gra gra had har hig Hub Hyp imp ind inf ins int int ion iro ite Kep lar lep lin lon lun mag mas mer mig mol Moo mut neg new New non non non nuc obs on- opt Ori oxi par per per phl pho Pla ple pol pos pre Pro pro pub qua rad rad rec red reg rem res rev rot Sak Sco sec seg sha sim sol sou sph sta ste Str sub sup T a the Tho tra tre tum uni vel vis wav wor > >>

Number of Results: 3079 Search : on
thermal emission
  گسیل ِ گرمایی   
gosil-e garmâyi (#)

Fr.: émission thermique   

thermal radiation.

thermal; → emission.

thermal excitation
  بر‌انگیزش ِ گرمایی   
barangizeš-e garmâyi

Fr.: excitation thermique   

A process in which collisions that occur between particles cause atoms or molecules to obtain additional kinetic energy.

thermal; → excitation.

thermal expansion
  سپانش ِ گرمایی   
sopâneš-e garmâyi

Fr.: expansion thermique   

The change in dimensions of a material resulting from a change in temperature.

thermal; → expansion.

thermal motion
  جنبش ِ گرمایی   
jonbeš-e garmâyi

Fr.: mouvement thermique   

The random motions and collisions of molecules, atoms, electrons, or other subatomic particles constituting an object at all temperatures above → absolute zero. The thermal motion of particles rises with the temperature of those particles and is governed by the laws of → thermodynamics. The most convincing experimental proof of thermal motion → Brownian motion.

thermal; → motion.

thermal neutron
  نوترون ِ گرمایی   
notron-e garmâ-yi (#)

Fr.: neutron thermique   

A neutron of very slow speed and consequently of low energy. The energy of thermal neutrons is of the same order as the → thermal energy of the atoms and molecules of the substance through which they are passing.

thermal; → neutron.

thermal radiation
  تابش ِ گرمایی   
tâbeš-e garmâyi (#)

Fr.: rayonnement thermique   

The energy radiated from an object in the form of → electromagnetic waves as a result of its → temperature. Thermal radiation ranges in → wavelength from the longest → infrared radiation through the → visible light spectrum to the shortest → ultraviolet rays. In opposition, → non-thermal radiation is caused by energetic particles.

thermal; → radiation.

thermalization
  یکگرمایی   
yekgarmâyi

Fr.: thermalisation   

1) The process by which a system reaches → thermal equilibrium. Thermalization results from energy exchange between the components constituting the system and their exchange with the outside medium. In a gas at a given temperature, molecules move with different velocities. The gas temperature corresponds to the mean velocity of the molecules, but individual molecules may deviate largely from the mean velocity. Some move very fast others slowly and change velocity upon collisions. Collisions reduce the energy of fast moving molecules and increase that of slow ones. In the process of thermalization → matter and → radiation are in constant interaction such that their → temperatures become identical. The process goes on until energy distribution reaches → equilibrium. The system is said to be → thermalized.
2) The condition where in an → atomic or → molecular → transition the → Boltzmann factor for the two → levels of transition takes on the value it would have in → thermodynamic equilibrium.

Verbal noun of → thermalize.

thermion
  گرمایون   
garmâyon

Fr.: thermion   

An electron that has been emitted from a heated body such as the hot cathode of an electron tube.

From therm- variant of → thermo- before a vowel + → ion.

thermionic emission
  گسیل ِ گرمایونی   
gosil-e garmâyoni

Fr.: émission thermionique   

Electrons gaining enough thermal energy to escape spontaneously from the cathode or dynodes and mimic photoelectrons.

thermion; → emission.

thermohaline convection
  همبز ِ گرماشور   
hambaz-e garmâšur

Fr.: convection thermohaline   

An instability in the ocean water that occurs when a layer of warm salt water is above a layer of fresh cold water of slightly higher density. In this process the hot salt water cools off and then, after having reached a higher density than the fresh water, sinks down even in the presence of stabilizing temperature gradients. This phenomenon explains the large-scale water movements in the oceans called themohaline circulation. First discussed by Melvin E. Stern (1960, Tellus 12, 172). → thermohaline mixing.

Thermohaline, from → thermo- + haline, from Gk. hals (genitive halos) "salt, sea;" cf. L. sal; O.Ir. salann; Welsh halen; O.C.S. sali "salt;" O.E. sealt; cf. O.N., O.Fris., Goth. salt, Du. zout, Ger. Salz from PIE *sal- "salt."

Garmâšur, from garmâ-thermo- + šur "salty" (Mid.Pers. šôr "salty," šorag "salt land;" cf. Skt. ksurá- "razor, sharp knife;" Gk. ksuron "razor;" PIE base *kseu- "to rub, whet").

thermonuclear flash
  درخش ِ گرماهسته‌ای   
deraxš-e garmâhaste-y

Fr.: flash thermonucléaire   

A theoretical interpretation for the → X-ray bursts observed toward → low-mass X-ray binary (LMXB) stars. According to models, X-ray bursts are produced on the surface of → neutron stars as a result of violent thermonuclear processes in a → hydrogen or → helium rich → layer. It is the → nuclear energy released in the → fusion of hydrogen and helium to heavier elements (e.g., Ni, Zn, and Se) in the → accreted matter which heats the upper layers of the neutron star so that X-rays are emitted from the surface (see, e.g., Taam, R.E., 1984, AIP Conf. Proc. 115, 263).

thermonuclear; → flash.

thermonuclear reaction
  واژیرش ِ گرماهسته‌ای   
vâžireš-e garmâhaste-yi (#)

Fr.: réaction thermonucléaire   

A nuclear reaction in which two or more atomic nuclei fuse into a single heavier nucleus by a collision of the interacting particles at extremely high temperatures. Chains of thermonuclear reactions, such as the → proton-proton chain and the → CNO cycle, account for the energy radiated from the Sun and more massive stars.

thermo- + → nuclear; → reaction.

thermonuclear runaway
  واژیرش ِ گرماهسته‌ای ِ لگام گسیخته   
vâžireš-e garmâhaste-yi-e legâm gosixté

Fr.: emballement thermonucléaire   

1) The uncontrolled → fusion of hydrogen into helium.
2) A → thermonuclear reaction process occurring at electron → degenerate conditions in stellar material, such as in → Type Ia supernovae.

thermonuclear; → runaway.

Vâžireš, → reaction; garmâhaste-yi, → thermonuclear; legâm gosixté literally "rampant, unrestrained," from legâm "bridle, rein" + gosixté "broken off, torn away," p.p. of gosixtan "to tear away, to break off."

thermonuclear supernova
  ابر-نو-اختر ِ گرماتوانیک   
abar-now-axtar-e garmâtavânik

Fr.: supernova thermonucléaire   

Same as → type Ia supernova

thermonuclear; → supernova.

third contact
  پرماس ِ سوم   
parmâs-e sevom

Fr.: troisième contact   

The end of the total phase of a solar eclipse marked by the trailing edge of the Moon first revealing the Sun.

third; → contact.

Tholen classification
  رده‌بندی ِ تولن   
radebandi-ye Tholen

Fr.: classification de Tholen   

A fundamental system for the classification of → asteroids based on → albedo and → spectral characteristics. The Tholen scheme includes 14 types with the majority of asteroids falling into one of three broad categories, and several smaller types. → C-type asteroid, → M-type asteroid, → S-type asteroid.

David J. Tholen (1984) Ph.D. thesis, University of Arizona; → classification.

Thomson
  تامسون   
Thomson

Fr.: Thomson   

The British physicist Sir Joseph John Thomson (1856-1940), discoverer of the electron (1897), Nobel Prize in Physics (1906). → Thomson atom, → Thomson cross section, → Thomson effect, → Thomson scattering, → Joule-Thomson effect.

Thomson atom
  اتم ِ تامسون   
atom-e Thomson (#)

Fr.: atome de Thomson   

The earliest theoretical description of the inner structure of atoms whereby an atom consists of a sphere of positive electricity of uniform density, throughout which is distributed an equal and opposite charge in the form of electrons. The diameter of the sphere was supposed to be of the order of 10-8 cm, the magnitude found for the size of the atom. → Rutherford atom.

Thomson; → atom.

Thomson cross section
  سکنج‌گاه ِ تامسون   
sekanjgâh-e Thomson

Fr.: section efficace de Thomson   

The → cross section involved the → Thomson scattering of electromagnetic waves by a free electron. It is defined by: σT = 8πre2/3, where re is the classical → electron radius. Its value is 0.665 245 x 10-28 m2.

Thomson; → cross; → section.

Thomson effect
  اسکر ِ تامسون   
oskar-e Thomson

Fr.: effet de Thomson   

The absorption or emission of heat when current is passed through a single conductor whose ends are kept at different temperatures. If current is passed from hotter end to colder end of a copper wire, then heat is evolved along the length of the wire. When current is passed from colder end to the hotter end, then heat is absorbed.

Thomson; → effect.

<< < "no abe acc act aff ama ani ant aps ast atm aut bar bif Boh bou cal car Cen chi Cla col com com Com con con con con con con con con con con con con cor cor Cou cur dec def Den det dif dim dis dis dou E-t edi ele ell ene ero exa exp ext fer Fla fra FU Gam geo gra gra had har hig Hub Hyp imp ind inf ins int int ion iro ite Kep lar lep lin lon lun mag mas mer mig mol Moo mut neg new New non non non nuc obs on- opt Ori oxi par per per phl pho Pla ple pol pos pre Pro pro pub qua rad rad rec red reg rem res rev rot Sak Sco sec seg sha sim sol sou sph sta ste Str sub sup T a the Tho tra tre tum uni vel vis wav wor > >>