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: 1068
phonetics
  آواییک   
âvâyik (#)

Fr.: phonétique   

A branch of linguistics dealing with the analysis, description, and classification of speech sounds. More specifically, phonetics deals with the physical production of → phonemes regardless of language, while → phonology studies how those sounds are put together to create meaningful words in a particular language.

From phonetic, from N.L. phoneticus, from Gk. phonetikos "vocal," from phonet(os) "utterable," verbal adj. of phonein "to speak clearly, utter," from → phone + -ikos, → -ics.

&ACIRC;vâyik, from âvâ, → phone, + -ik, → -ics.

phono-
  آوا-   
âvâ- (#)

Fr.: phono-   

A combining form meaning "sound, voice," used in the formation of compound words. Also phon-, especially before a vowel.

From Gk. phon-, phono-, form → phone "voice, sound, speech"

phonology
  آواشناسی   
âvâšnâsi (#)

Fr.: phonologie   

A branch of linguistics that studies the rules in any given language that govern how → phonemes are combined to create meaningful words. Phonology and → phonetics study two different aspects of sound, but the concepts are dependent on each other in the creation of language.

phono-; → -logy.

phonon
  فونون   
fonon (#)

Fr.: phonon   

A quantum of vibrational or acoustic energy in a crystal lattice, being the analog of a photon of electromagnetic energy.

phono- + → -on.

phosphine
  فوسفین   
fosfin

Fr.: phosphine   

A colorless, flammable, and explosive gas at ambient temperature with unpleasant smell of rotten fish or garlic. Named also hydride of phosphorus (PH3), it is highly poisonous in nature. On cooling to 185.5 K, phosphine condenses to a liquid and on cooling to 139.5 K, it solidifies. By heating in the absence of air at 713 K or by passing an electric spark through it, phosphine breaks into its elements. Small amounts occur naturally from the break down of organic matter. It is heavier than air and slightly soluble in water. Phosphine is used in semiconductor and plastics industries, in the production of a flame retardant, and as a pesticide in stored grain. Phosphine has two strong absorption bands in → infrared at 10 and 9 μm.

From phosph-, variant of phospho-, denoting → phosphorus, used before a vowel + suffix -ine, ultimately from L. -inus, used to form names of chemical substances, especially basic (alkaline) substances, alkaloidal substances, or halogen elements.

phosphorescence
  فسفرستی   
fosforesti

Fr.: phosphorescence   

A specific type of → photoluminescence that continues for an appreciable time after the stimulating process has ceased. Phosphorescence is due to the existence of metastable → excited states of the atoms and molecules from which a change to the normal state is hindered for some reason or other. The change from the → metastable metastable state to the normal one becomes possible only as a result of some additional excitation, for example the application of heat.

phosphorus; → -escence.

phosphorus
  ۱) فسفر؛ ۲) روجا، ستاره‌ی ِ بامدادی   
1) fosfor (#); 2) rujâ, setâre-ye bâmdâdi (#)

Fr.: phosphore   

1) Nonmetallic chemical element; symbol P. → Atomic number 15; → atomic weight 30.97376; → melting point 44.1°C; → boiling point about 280°C. It was discovered by the German merchant Hennig Brand in 1669.
2) Greek name for the planet → Venus when it appears as a → morning star.

L. Phosphorus "morning star," from Gk. Phosphoros "morning star," literally "light bearing," from phos "light" + phoros "bearer," from pherein "to carry," cognate with Pers. bordan "to carry, lead" (→ periphery). The chemical element is such called because of its white color.

1) Fosfor, loan from Fr.
2) → morning star.

photino
  فوتینو   
fotino (#)

Fr.: photino   

The supersymmetric partner of the → photon.

From phot, from → photon + -ino supersymmetric particle suffix.

photo-
     
šid- (#), nur- (#)

Fr.: photo-   

From Gk. combining form of phos (genitive photos).

Šid- "light, sunlight," from Mid.Pers. šêt "shining, radiant, bright;" Av. xšaēta- "shining, brilliant, splendid, excellent."
Nur-, → light.

photoabsorption
  شید-درشم   
šid-daršam

Fr.: photoabsorption   

A situation in which all of the energy of a photon is transferred to an atom, molecule, or nucleus.

photo- + → absorption.

photocathode
  شید-کاتود، نور-کاتود   
šid-kâtod, nur-kâtod

Fr.: photocathode   

Electrode capable of releasing electrons when illuminated.

photo- + → cathode.

photochemistry
  شید-شیمی، نور-شیمی   
šid-šimi, nur-šimi

Fr.: photochimie   

The study of the chemical and physical changes occurring when a molecule or atom absorbs photons of light.

photo- + → chemistry.

photodesorption
  شید-واشم   
šid-vâšam

Fr.: photodésorption   

Th desorption of surface substances by ultraviolet radiation.

photo-; → desorption.

photodisintegration
  شید-واپاشی، نور-واپاشی   
šidvâpâši, nurvâpâši

Fr.: photodésintégration   

The process by which atomic nuclei are broken apart into their constituent protons and neutrons by the impact of high energy gamma photons. Photodisintegration takes place during the core collapse phase of a → Type II supernova explosion.

photo- + → disintegration.

photodissociate
  شید-واهزیدن   
šid-vâhazidan

Fr.: photodissocier   

To dissociate a → molecule by → radiation. See also → photodissociation.

photo-; → dissociate.

photodissociation
  شید-واهزش، نور-واهزش   
šid-vâhazeš, nur-vâhazeš

Fr.: photodissociation   

The → dissociation of a → chemical compound by → radiation  → energy.

Verbal noun of → photodissociate; → -tion.

photodissociation region (PDR)
  ناحیه‌ی ِ شید-واهزش، ~ نور-واهزش   
nâhiye-ye šid-vâhazeš, ~ nur-vâhazeš

Fr.: région de photodissociation   

A neutral region at the boundary of a → molecular cloud created by the penetration of → far ultraviolet (FUV) radiation from associated stars. The FUV radiation (6 eV ≤ hν ≤ 13.6 eV) dissociates the molecules and heats the gas and dust. A warm, atomic → H I region is thus created and the chemistry and thermal balance of the region are determined by the penetrating FUV photons. The progressive absorption of FUV photons leads to the occurrence of transitions between atomic and molecular phases, such as H I/H2 and C II/C I/CO transitions. By extension, any neutral region where the physics is controlled by FUV photons can be called a PDR, as it is the case for → diffuse interstellar clouds or the edge of → circumstellar disks. The PDR concept was first studied by A. G. G. M. Tielens and D. Hollenbach (1985, ApJ 291, 722).

photodissociation + → region.

photoelectric
  شید-برقی، نور-برقی   
šid-barqi, nur-barqi

Fr.: photoélectrique   

Pertaining to electronic or other electrical effects that are due to the action of electromagnetic radiation, especially visible light.

photo- + → electric.

photoelectric current
  جریان ِ شید-برقی   
jarayân-e šid-barqi

Fr.: courant photoélectrique   

The current produced in an → photoelectric effect process when → photoelectrons are received at the positive electrode.

photoelectric; → current.

photoelectric effect
  ا ُسکر ِ شید-برقی، ~ نور-برقی   
oskar-e šid-barqi, ~ nur-barqi

Fr.: effet photoélectrique   

The process of release of electrically charged particles (usually → electrons) as a result of irradiation of matter by light or other → electromagnetic radiation. The classical electromagnetic theory was unable to account for the following characteristics of the phenomenon. Light below a certain threshold frequency, no matter how intense, will not cause any electrons to be emitted. Light above that frequency, even if it is not very intense, will always cause electrons to be ejected. The electrons are ejected after some nanoseconds, independently of the light intensity. The maximum kinetic energy of the emitted electrons is a function of the frequency and does not dependent on the intensity of the incident light. The classical theory could not explain how a train of light waves spread out over a large number of atoms could, in a very short time interval, concentrate enough energy to knock a single electron out of the metal. In 1905, based on Planck's idea of → quanta, Einstein proposed that light consisted of quanta (later called → photons); that a given source could emit and absorb radiant energy only in units which are all exactly equal to the radiation frequency multiplied by a constant (→ Planck's constant); and that a photon with a frequency over a certain threshold would have sufficient energy to eject a single electron. His photoelectric equation is descibed as (1/2)mu2 = hν - A, where m is the electron mass, u is the electron velocity, h is Planck's constant, ν is the frequency, and A the → work function, which represents the amount of work needed by electrons to get free of the surface. See also → photoelectron, → photoelectric current, → external photoelectric effect, → internal photoelectric effect.

photoelectric; → effect.

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