An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 692
âškâreš (#)

Fr.: détection   

The act or state of detecting, → detect
Any operation on an electrical or electromagnetic signal to recover information from it.

M.E., from L.L. detection-, from detect(us), → detect, + -ion.

škâreš, from âškâr present-tense stem of âškâridandetect + verbal noun suffix.

detective quantum efficiency (DQE)
  کار‌آیی ِ کوانتومی ِ آشکارش   
kârâyi-ye kuântomi-ye âškâreš

Fr.: rendement quantique de détection   

The square of the ratio of the output → signal-to-noise (S/N) to the input S/N.

Detective, adj. of → detect; → quantum; → efficiency.


Fr.: détectivité   

A performance criterion for an electronic detector, reciprocal of the corresponding → noise-equivalent power (D = 1/NEP).

From detective, relating to → detect + → -ity.

âškârgar (#)

Fr.: détecteur   

A device whose main function is detection.
Any device or array of electronic sensors connected to a computer, used to detect the passage of a particle or photon; e.g. a → charge-coupled device (CCD).

L.L. detector, from deteg(ere), → detect, + -tor suffix forming agent noun.

škârgar, from âškâr present-tense stem of âškâridan "to detect" + -gar a suffix of agent nouns, from kar-, kardan "to do, to make" (Mid.Pers. kardan, O.Pers./Av. kar- "to do, make, build," Av. kərənaoiti "makes," cf. Skt. kr- "to do, to make," krnoti "makes," karma "act, deed;" PIE base kwer- "to do, to make").


Fr.: déterminant   

An agent or factor that determines the nature of something or that fixes or conditions an outcome.
Math.: An algebraic expression used in the solution of systems of linear equations, which consists of the sum of products of elements, each with an appropriate algebraic sign, usually written in a square array.

From → determine + -ant suffix forming noun.

Âtarmgar, from âtarm present stem of âtarmidandetermine + -gar, → detector.

  آترم، آترمش   
âtarm, âtarmeš

Fr.: détermination   

The act of deciding definitely and firmly; the result of such an act of decision.

Verbal noun of → determine.


Fr.: déterminer   

1) General: To settle or decide by choice of alternatives or possibilities.
2) Math.: To fix or define the position, form, or configuration of.
3) Logic: To explain or limit by adding differences.

From O.Fr. déterminer, from L. determinare "set limits to," from → de- + terminare "to mark the end or boundary," from terminus "boundary, border, end," → term.

Âtarmidan, from âtarm + verb forming suffix -idan; âtarm from intensive prefix â- + tarm "limit, boundary," → term.

  آترم باوری   

Fr.: déterminisme   

The belief that every event is necessitated by antecedent events and conditions together with the laws of nature. → deterministic physics.

From → determine + → -ism.

Âtarmbâvari, from âtarm, → determine, + bâvari, noun of bâvar "beleif;" Mid.Pers. wâbar "beleif;" Proto-Iranian *uar- "to choose; to convince; to believe;" cf. Av. var- "to choose; to convince" varəna-, varana- "conviction, faith;" O.Pers. v(a)r- "to choose; to convince;" Skt. vr- "to choose," vara- "choosing."


Fr.: déterministe   

Of, pertaining to, or dealing with → determinism.

From determinist + → -ic.

deterministic physics
  فیزیک ِ آترم‌باور   
fizik-e âtarmbâvar

Fr.: physique déterministe   

The classical representation of the laws of nature according to which a particular future state (B) will arise from a particular past one (A). In contrast to → quantum physics which deals with the probability for the transition from A to B.

Deterministic, adj. of determinism; → physics.

deterministic theory
  نگره‌ی ِ آترم‌باور   
negare-ye âtarmbâvar

Fr.: théorie déterministe   

A theory in which specification of the initial value of all relevant variables of the system is sufficient to calculate the past values and to predict the future values of such variables for any arbitrary time. Moreover, it is possible, for any arbitrary time, to assign a value to all the variables characterizing the system. In quantum mechanics, the time evolution of the → wave function, governed by the → Schrodinger equation, is deterministic. Quantum mechanics, however, is a non deterministic theory because of the probabilistic nature of the predictions for the values of the → observables of a quantum system.

deterministic; → theory.

tarâkidan (#)

Fr.: détoner, faire détoner, faire exploser   

1) To set off a → detonation. 2) To explode or cause to explode.

From L. detonatus, p.p. of detonare "to thunder down, roar out," from → de- + tonare "to thunder," cf. Pers. tondar "thunder," Skt. stanáyati "thunders," tanyatá- "thundering," Gk. stonos "groan," stenein "to groan," Thôrr "the Old Norse god of thunder," P.Gmc. *thunraz (Du. donder, Ger. Donner "thunder," E. thunder, Fr. tonnerre), PIE base *(s)tene- "to resound, thunder."

Tarâkidan "to split, cleave; to make a noise in splitting," variants tarakidan, taraqidan, taraqqé "firecracker," from tarâk/tarak "split, cleft, crack; the noise of anything when splitting or cleaving," maybe related to Pers. dar-, daridan "to tear, cut," Av. dar- "to tear," dərəta- "cut," auua.dərənant- "shattering," Skt. dar- "to crack, split, break, burst," darati "he splits," cf. Gk. derma "skin," E. tear, Ger. zerren "to pull, to tear," zehren "to undermine, to wear out," PIE base *der- " to split, peel, flay."

tarâk (#)

Fr.: détonation   

Instantaneous combustion or conversion of a solid, liquid, or gas into larger quantities of expanding gases accompanied by heat, shock, and a noise. → deflagration; → explosion.

Verbal noun of → detonate.


Fr.: deutérer   

To add → deuterium to a → chemical compound.

From L. deuter(ium), → deuterium, + -ate a suffix forming verbs from L. -atus (masc.), -ata (fem.), -atum (neut.).

Doteridan, infinitive from doteriom, → deuterium.


Fr.: deutéré   

Describing a → chemical compound to which → deuterium is added.

Past participle of → deuterate.

deuterated species
  آرز ِ دوتریده   
âraz-e doteridé

Fr.: espèce deutérée   

A chemical species in which the → deuterium abundance is → enriched with respect to a mean standard value.

deuterated; → species.


Fr.: deutération   

The process of introducing → deuterium into a → chemical compound.

Verbal noun of → deuterate.

doteriom (#)

Fr.: deutérium   

The first heavy → isotope of → hydrogen (2H), the → nucleus of which consists of one → proton and one → neutron. Like hydrogen, the deuterium atom has one electron, and therefore has similar chemical properties to hydrogen, forming, e.g., → heavy water (HDO). Deuterium is generated only during → Big Bang nucleosynthesis. It is destroyed in stars through the reaction D + p → 3He + γ (→ deuterium burning). As there is no net source of deuterium in stars, its abundance has decreased steadily since the → Big Bang, and any value measured today must be a lower limit on the primordial value. However, → fractionation processes lead to local → deuterium enhancements; see → deuterium abundance for more details. Theoretical models of Big Bang nucleosynthesis predict D/H to be (2.61 ± 0.15) x 10-5 (Steigman et al. 2007, MNRAS 378, 576) and this is closely matched by measurements from intergalactic Dα line absorption observations toward high-redshift quasars that give 2.53±0.04 x 10-5 (Cooke et al. 2014, ApJ 781, 31).
See also: → deuterated, → deuterated species, → deuterium enrichment, → deuterium enrichment factor, → deuterium fractionation, → deuteron.

From Gk. deutero-, combining form of deuterios "second" + -ium suffix occurring in scientific coinages on a Latin model. Coined in 1933 by U.S. chemist Harold C. Urey (1893-1981).

deuterium abundance
  فراوانی ِ دوتریوم   
farâvâni-ye doteriom

Fr.: abondance de deutérium   

The number of → deuterium (D) atoms with respect to → hydrogen (H) in an astrophysical object. Deuterium is a primordial product of → Big Bang nucleosynthesis. According to theoretical models, the primordial D/H ratio is estimated to be (2.61 ± 0.15) x 10-5 (Steigman et al. 2007, MNRAS 378, 576). Nuclear reactions in stars convert D into He tending to a lower D/H ratio in the → interstellar medium over time (→ deuterium burning). However, chemical and physical → fractionation processes can produce local → enhancements in the D/H ratio. For example, low-temperature ion-molecule reactions in → molecular cloud cores can enhance the D/H ratio in icy grains by as much as two orders of magnitude above that observed in the interstellar medium.
The D/H ratio in the → solar nebula, estimated from observations of CH4 in → Jupiter and → Saturn, is 2.1 ± 0.4 x 10-5, assuming that these gaseous planets obtained most of their hydrogen directly from solar nebula gas. This estimate is consistent with → protosolar D/H value inferred from the → solar wind implanted into lunar soils. Moreover, the D/H ratio derived from the interstellar Dα line (which is displaced from the → Lyman alpha line of 1H at 1216 Å by -0.33 Å) is 1.6 x 10-5 (Linsky et al. 1995, ApJ 451, 335).
High D/H ratios (relative to Earth's water) are measured spectroscopically from water in three comets (all from the → Oort cloud): → Halley (3.2 ± 0.1 x 10-4), → Hyakutake (2.9 ± 1.0 x 10-4), and → Hale-Bopp (3.3 ± 0.8 x 10-4). These are all about twice the D/H ratio for terrestrial water (1.49 x 10-4) and about 15 times the value for the above-mentioned solar nebula gas. Note that → carbonaceous chondrites have the highest water abundance of all → meteorites. Their D/H ratios range from 1.20 x 10-4 to 3.2 x10-4 with a case at (7.3 ± 1.2) x10-4.
Different authors interpret the high comet ratios in very different ways. Some consider the high D/H ratio as evidence against a cometary origin of most of the terrestrial water. Others, on the contrary, argue that comets are the main reservoir of deuterium-rich water that raised the terrestrial D/H a factor of six above the protosolar value.
For more details see "Sources of Terrestrial and Martian Water" by Campins, H. and Drake, M. (2010) in "Water & life: the unique properties of H20" Eds. R. Lynden-Bell et al. CRC Press, pp. 221- 234.

deuterium; → abundance.

deuterium burning
  سوزش ِ دوتریوم   
suzeš-e doteriom

Fr.: combustion du deutérium   

The fusion of a deuterium nucleus with a proton which produces the lightest isotope of helium: D + H → 3He + γ. Deuterium burning occurs in stellar cores at a temperature exceeding 106 K. The onset of deuterium burning marks the end of the → protostellar collapse. It is the only → nuclear reaction that occurs in → brown dwarfs. In normal stars, it is the second step in the → proton-proton chain which leads to the formation of 4He, allowing stars to arrive on the → main sequence.

deuterium; → burning.

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