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

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 59 Search : miss
permission
  پرزامش   
parzâmeš

Fr.: permission   

The act of permitting. Authorization granted to do something.

verbal noun of → permit; → -tion.

photoemissive effect
  اسکر ِ شید-گسیلی   
oskar-e šid-gosili

Fr.: effet photoémissif   

The emission of electrons as a result of incident radiation in the → photoelectric effect. Also called → external photoelectric effect.

photo- + → emissive; → effect.

radio continuum emission
  گسیل ِ پیوستار ِ رادیویی   
gosil-e peyvastâr-e râdio-yi

Fr.: émission de continuum radio   

A → continuum emission with frequencies in the radio range of the electromagnetic spectrum.

radio; → continuum; → emission.

radio emission
  گسیل ِ رادیویی   
gosil-e râdio-yi

Fr.: émission radio   

Electromagnetic radiation carried by → radio waves.

radio; → emission.

secondary emission
  گسیل ِ دومان   
gosil-e dovomân

Fr.: émission secondaire   

The emission of → secondary electrons from the surface of a material when an incident particle (often, charged particle such as electron or ion) impacts the material with sufficient energy.

secondary; → emission.

space mission
  گسیلان ِ فضایی   
gosilân-e fazâyi

Fr.: mission spatiale   

A manned or unmanned space flight outside the Earth's atmosphere.

space; mission, from L. missionem (nominative missio) "act of sending," from mittere "to send," of unknown origin.

Gosilân, from gosil, variant gosi "sending away, dismission;" Mid.Pers. wisé "to despatch" (Parthian Mid.Pers. wsys- "to despatch;" Buddhist Mid.Pers. wsydy "to despatch;" Sogdian 'ns'yd- "to exhort"), from Proto-Iranian *vi-sid- "to despatch, send off," from prefix vi- "apart, away, out," + *sid- "to call" + -ân nuance suffix; fazâyi adj. of fazâ, → space.

spontaneous emission
  گسیل ِ سرخود   
gosil-e sarxod

Fr.: émission spontanée   

The emission of electromagnetic radiation from an atom or molecule that does not depend on the presence of external fields.

spontaneous; → emission.

stimulated emission
  گسیل ِ گوازیده   
gosil-e gavâzidé

Fr.: émission stimulée   

The process by which an electron, which is already in an excited state (an upper energy level, in contrast to its lowest possible level or "ground state"), can "stimulate" a transition to a lower level, producing a second photon of the same energy. The quantum energy of the incoming photon should be equal to the energy difference between its present level and the lower level. This process forms the basis of both the → laser and → maser. Same as → induced emission.

Stimulated, p.p. of → stimulate; → emission.

submission
  درسپرد   
dar-sepord

Fr.: soumission   

An act or instance of submitting. The condition of having submitted. → submit

Verbal noun of → submit.

thermal emission
  گسیل ِ گرمایی   
gosil-e garmâyi (#)

Fr.: émission thermique   

thermal radiation.

thermal; → emission.

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.

transmission
  تراگسیل   
tarâgosil (#)

Fr.: transmission   

1) The act or process of transmitting. The fact of being transmitted.
2) The broadcasting of electromagnetic waves from one location to another, as from a transmitter to a receiver.

Verbal noun of → transmit.

transmission band
  باند ِ تراگسیل   
bând-e tarâgosil (#)

Fr.: bande de transmission   

The frequency range above the cutoff frequency in a waveguide or transmission line.

transmission; → band.

transmission coefficient
  همگر ِ تراگسیل   
hamgar-e tarâgosil

Fr.: coefficient de transmission   

The ratio given by the → amplitude (or energy) of a transmitted wave divided by the amplitude (or energy) of the incident wave.

transmission; → coefficient.

transmission grating
  توری ِ تراگسیلی   
turi-ye tarâgosili

Fr.: réseau par transmission   

A diffraction grating that has grooves ruled onto a transparent material so that a beam of light passed through the grating is partly split into spectral orders.

transmission; → grating.

transmission loss
  دسترفت ِ تراگسیل   
dastraft-e tarâgosil

Fr.: perte de transmission   

A decrease in power in transmission from one point to another.

transmission; → loss.

transmission system
  راژمان ِ تراگسیل   
râžmân-e tarâgosil

Fr.: système de transmission   

An assembly of elements which are capable of functioning together to transmit power or signals.

transmission; → system.

two-photon emission
  گسیل ِ دو-فوتونی   
gosil-e do-fotoni

Fr.: émission à deux photons   

The simultaneous emission of two photons whose sum of energies is equal to that of a single electron transition. The energy of each individual photon of the pair is not fixed, so that the spectrum of two-photon emission is continuous from the wavelength of that transition to infinity. In practice, there is a peak in wavelength distribution of the emitted photons. Two-photon emission is studied atomic physics with application in astrophysics, as it contributes to the continuum radiation from → planetary nebulae. It was recently observed in condensed matter and specifically in → semiconductors.

two; → photon; → emission.

weak emission-line central star (wel)
  ستاره‌ی ِ مرکزی با خط ِ گسیلی ِ نزار   
setâre-ye markazi bâ xatt-e gosili-ye nezâr

Fr.: étoile centrale à faibles raies d'émission   

A member of a class of cntral stars of planetary nebula, → CSPN, which have weaker and narrower emission lines than → Wolf-Rayet-like CSPNe (Tylenda et al. 1993, A&AS 102, 595).

weak; → emission; → line.

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