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

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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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

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Number of Results: 1307
Couette-Taylor flow
  تچان ِ کویءت-تیلر   
tacân-e Couette-Taylor

Fr.: écoulement de Couette-Taylor   

In fluid mechanics, the motion of a fluid between two concentric cylinders when one or both of the cylinders rotate.

Couette flow; Geoffrey Ingram Taylor (1886-1975), British physicist; → flow.

coulomb (C)
  کولن   
coulomb (#)

Fr.: coulomb   

The unit of → electric charge in the → mks system, equal to the quantity of charge transferred in one second by a steady current of one → ampere. One coulomb represents a charge of approximately 6.241 506 × 1018 → electrons. Compared with the charge unit in the → cgs system, 1 C = 2.998 × 109 → esu.

Named after the French physicist Charles Augustin de Coulomb (1736-1806), who pioneered research into magnetism and electricity.

Coulomb barrier
  ورغه‌ی ِ کولن   
varqe-ye Coulomb (#)

Fr.: barrière de Coulomb   

The energy barrier due to electrostatic interaction that two nuclei (for example two protons) need to overcome so they can get close enough to undergo nuclear fusion (to form a helium).

coulomb; → barrier.

Coulomb collision
  همکوبش ِ کولن   
hamkubeš-e Coulomb

Fr.: collision coulombienne   

A particle → collision where the dominant force is described by → Coulomb's law. The collision results in deflections of the particles away from their initial paths.

coulomb; → collision.

Coulomb energy
  کاروژ ِ کولن   
kâruž-e Coulomb

Fr.: énergie coulombienne   

The → potential energy from which derives the repulsive electrostatic force between two → charged particles. For example, the Coulomb energy between two protons is e2/r ~ 0.5 MeV, which is small compared with the average → binding energy per particle (~ 8 Mev). However the Coulomb repulsion becomes important for heavy nuclei. The total Coulomb energy of a nucleus is given by: (3/5) Z(Z - 1)e2/R, where Z is the → atomic number, e the charge, and R the nuclear radius. Since R ∝ A1/3 and Z is roughly proportional to A, the Coulomb energy is roughly proportional to A5/3. On the other hand, the total binding energy is proportional to A, which means that the relative importance of the repulsive electrostatic energy increases with increasing mass number as A2/3.

coulomb; → energy.

Coulomb excitation
  بر‌انگیزش ِ کولن   
barangizeš-e Coulomb

Fr.: excitation coulombienne   

The transition to a higher → energy level than → ground state undergone by an atomic nucleus when a → charged particle of appropriate energy moves past it.

coulomb; → excitation.

Coulomb force
  نیروی ِ کولن   
niru-ye Coulomb (#)

Fr.: force de Coulomb   

An attractive or repulsive → electrostatic force between objects bearing electric charge, as described by → Coulomb's law. If the charges are of opposite sign, then the force is attractive; if thy are of the same sign, the force is repulsive.

Coulomb; → force.

Coulomb gauge
  گز ِ کولن   
gaz-e Coulomb

Fr.: jauge de Coulomb   

The optimum → gauge for steady fields, defined by: ∇.A = 0, where A is the → magnetic vector potential. Also called transverse gauge.

Coulomb; → gauge.

Coulomb interaction
  اندرژیرش ِ کولن   
andaržireš-e Coulomb

Fr.: interaction de Coulomb   

The reciprocal force between two or more → charged particles according to → Coulomb's law.

coulomb; → interaction.

Coulomb pressure
  فشار ِ کولن   
fešâr-e Coulomb

Fr.: pression de Coulomb   

The repulsive interaction due to the → Coulomb energy between two ions. If the ionic charge is Z, then the Coulomb potential energy is Z2e2/a, where a is some typical separation between the ions. The Coulomb pressure is expected to become important when the ratio ΓC = Z2e2/akT is much larger than 1. In that case, Coulomb effects dominate those of → thermal agitation and the gas settles down into a → crystal.

Coulomb; → pressure.

Coulomb's law
  قانون ِ کولن   
qânun-e Coulomb (#)

Fr.: loi de Coulomb   

The electrical force between two charged objects is directly proportional to the product of the quantity of charge on the objects and inversely proportional to the square of the separation distance between the two objects

coulomb; → law.

count
  ۱) شماردن؛ ۲) شمار   
1) šomârdan (#); 2) šomâr (#)

Fr.: 1) compter; 2) coup   

1) (v.) To enumerate; reckon up; calculate; compute.
2) (n.) A single ionizing event registered by a device such as a → Geiger counter.
The indication of the total number of ionizing events registered by a device.

From O.Fr. conter "add up," from L. computare, → compute.

Šomârdan, from Mid.Pers. ôšmârtan, ôšmurtan "to reckon, calculate, enumerate, account for," from Av. base (š)mar- "to have in mind, remember, recall," pati-šmar- "to recall; to long for," hišmar-, cf. Skt. smar- "to remember, become aware," smarati "he remembers," L. memor, memoria, Gk. mermera "care," merimna "anxious thought, sorrow," martyr "witness."

countdown
  فروشمارش   
forušomâreš

Fr.: compte à rebours   

1) The backward counting in fixed time units from the initiation of a project, as a rocket launching, with the moment of firing designated as zero.
2) The final preparations made during this period (Dictionary.com).

count; → down.

counter
  شمارگر   
šomârgar (#)

Fr.: compteur   

Generally,a device for indicating a number or amount.
Any of various instruments for detecting ionizing radiation and for registering counts. → Geiger counter.

M.E. countour, from O.Fr. conteor, from L. computator, from computa(re) "to compute" + → -tor suffix forming personal agent nouns mainly from verbs.

Šomârgar, from šomâr present tense stem of šomârdan "to count," → count + agent suffix -gar.

counter-
  پاد-   
pâd- (#)

Fr.: contre-   

A prefix used with the meanings "against, contrary, opposite." → contra-.

M.E. countre-, from O.Fr. contre-, from L. contra "opposite, against;" PIE base *kom- "beside, near, by, with."

Pâd- "contrary to; against; opposing," variants pâ- (pâsox, pâzahr, pâhang, → response), paž- (pažvâk, → echo, pažâvand "the bar of a door or a gate, door lock"), baž- (bažkam, → forbidden), pat- (patvâz, → correspond), pa- (panâh, padid), from Mid.Pers. pât-, from O.Pers. paity "agaist, back, opposite to, toward, face to face, in front of," Av. paiti, akin to Skt. práti "toward, against, again, back, in return, opposite," Pali pati-, Gk. proti, pros "face to face with, toward, in addition to, near;" PIE *proti.

counterbalance
  پاتراز   
pâtarâz

Fr.: contrebalance   

An equal weight, power, or influence acting in opposition.

counter-; → balance.

counterclockwise
  پادساعت‌سو   
pâdsâ'atsu (#)

Fr.: en sens inverse des aiguilles d'une montre   

In a direction opposite to the rotating hands of a clock.

From counter- "contrary; opposite; opposing," + → clockwise.

Pâdsâ'atsu, from pâd-, → counter-, + sâ'atsu, → clockwise.

counterexample
  پادنمونه   
pâdnemuné

Fr.: contre-exemple   

Logic: An individual case or instance that falsifies a universal generalization. A counterexample to an → argument is a situation in which the → premises are → true, but the → conclusion is → false. For example, "All dogs are mammals" (true). "All cats are mammals" (true). "Therefore, all cats are dogs." (false).

counter-; → example.

counterflow
  پادتچان   
pâdtacân

Fr.: contreflot   

The movement of a fluid in the opposite direction to a fluid flowing in the same cross section of a turbulent medium.

counter-; → flow.

counterglow
  پادفروغ   
pâdforuq

Fr.: gegenschein   

Same as → gegenschein.

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