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: 1279
self-similar
  خودهمانند   
xod-hamânad

Fr.: auto-similaire   

1) Of a geometric figure, having a structure analogous or identical to its overall structure. → fractal.
2) The quality of a variable entity in which the shape does not change with time, such as a → self-similar process.

self-; → similar.

self-similar process
  فراروند ِ خودهمانند   
farâravand-e xod-hamânad

Fr.: processus auto-similaire   

A process that is invariant in distribution under scaling of time. Schematically, images taken of such a process at different time scales will look similar.

self-; → similar; → process.

self-similarity
  خودهمانندی   
xod-hamânadi

Fr.: auto-similarité   

The property of being → self-similar.

self-; → similarity.

Sellmeier's equation
  هموگش ِ زلمایر   
hamugeš-e Sellmeier

Fr.: équation de Sellmeier   

An empirical relation between the → refractive index of a medium and the wavelength of light passing through the medium: n2 - 1 = Σ (Aiλ2/(λ2 - λi2)), where n is the refractive index at wavelength λ, and Ai and λi are constants.

Named after Wolfgang Sellmeier who derived the equation in 1871; → equation.

semantic
  چماریک   
cemârik

Fr.: sémantique   

1) Of, pertaining to, or arising from the different meanings of words or other signs and symbols.
2) Of or pertaining to → semantics.

From Fr. sémantique, from Gk. semantikos "significant," from semainein "to show, signify, indicate by a sign," from sema "sign."

Cemârik, from cemâr, → meaning, + -ik, → -ic.

semantics
  چماریک   
cemârik

Fr.: sémantique   

The study of the → meaning of signs or symbols, as opposed to their formal relations (→ syntactics).

semantic; → -ics.

semen
  شسر   
šosar (#)

Fr.: sperme, semence   

Biology: The male reproductive fluid, containing spermatozoa in suspension. → inseminate, → insemination; → fecundate, → fecundation.

M.E., from L. semen "seed;" akin to serere "to sow;" cf. O.C.S. seme, O.H.G. samo; E. sow.

From Mid.Pers. šusar "semen; liquid, fluid;" Av. xšudra- "semen; liquid, fluid;" related to Pers. šostan/šuy- "to → wash."

semi-
  نیم-، نیمه-   
nim- (#), nimé- (#)

Fr.: semi-, demi-   

A combining form meaning "half," freely prefixed to English words of any origin.

From L. semi- "half," from PIE *semi-; cf. Skt. sāmi "half," sāmi-krita- "half-done;" Gk. hemi- "half;" O.E. sam-; Goth. sami- "half."

Nim, nimé "half," from Mid.Pers. nêm, nêmag "half;" Av. naēma- "half;" cf. Skt. néma- "half."

semi-forbidden line
  خط ِ نیمه-بژکم   
xatt-e nime-bažkam

Fr.: raie semi-interdite   

A → spectral line for which the upper and lower → energy levels have different values of S, the total → spin angular momentum. These lines violate the quantum mechanical → selection rule under → LS coupling, ΔS = 0. For example, the Ca I λ6573 line results from transition between the upper → triplet state (3P1) with a total spin angular momentum S = 1 and the → ground state, a → singlet state (1S0, total spin angular momentum S = 0). A semi-forbidden line is marked by a right bracket following the atom name, i.e. Ca I], in the above-mentioned case. Same as → interconnection line and → intersystem line.

semi-; → forbidden; → line.

semi-forbidden transition
  گذرش ِ نیمه-بژکم   
gozareš-e nime-bažkam

Fr.: transition semi-interdite   

An → atomic transition whose probability is reduced by a factor of the order of 106 because of → selection rules. Same as → interconnection line.

semi-; → forbidden; → transition.

semi-major axis
  آسه‌ی ِ نیمه‌مهین   
âse-ye nimeh-mehin

Fr.: demi grand axe   

Half the length of the major axis of an ellipse; a standard element used to describe an elliptical orbit. see orbital elements

semi-; → major; → axis.

semiconductor
  نیم-هازا، نیمه-رسانا   
nim-hâzâ, nime-rasânâ

Fr.: semi-conducteur   

Any of various solid crystalline substances, such as germanium or silicon, which has conducting properties intermediate between metals and insulators.

semi-; → conductor.

semiconductor junction
  جوهه‌ی ِ نیم-هازا   
juhe-ye nim-hâzâ

Fr.: jonction semi-conducteur   

In a semiconductor device, a region of transition between semiconducting regions of different electrical properties.

semiconductor; → junction.

semiconvection
  نیم-همبز   
nim-hambaz

Fr.: semi-convection   

An instability occurring in the region just outside the → convective core of a → massive star. The instability occurs when a → superadiabatic layer is stabilized by a chemical gradient. In fact, semiconvection takes place if → Schwarzschild's criterion for convection is fulfilled but at the same time → Ledoux's criterion is not fulfilled. The time-scale of semiconvection is the thermal time-scale, which is short compared to the nuclear time-scale in → main sequence stars but long compared to the time-scale of convection. However, semiconvection has a profound influence on the → post-main sequence star evolution. It affects the convective mixing above the hydrogen shell source, determines the appearance and extent of → blue loops in the → Hertzsprung-Russell diagram during core → helium burning, and is essential for defining the extent of the convective cores during core helium burning (See, e.g., N. Langer, 2012, Ann. Rev. Astron. Astrophys. 50, 107).

semi-; → convection.

semidetached binary
  دُرین ِ نیم-جدا   
dorin-e nim-jodâ

Fr.: bianire semi-détachée   

A binary system whose secondary member fills its Roche lobe but whose primary member does not.

semi-; detached, p.p. of detach, from O.Fr. destachier (Fr. détacher), from des- "apart," + -tachier (as in atachier "to attach"); → binary.

Dorin, → binary; nim-jodâ, from nim-semi- + jodâ "separate," from Mid.Pers. yut "separate, different;" Av. yuta- "separate, apart."

semidetached system
  راژمان ِ نیم-جدا   
râšmân-e nim-jodâ

Fr.: système semi-détaché   

Same as → semidetached binary.

semi-; detached, p.p. of detach, from O.Fr. destachier (Fr. détacher), from des- "apart," + -tachier (as in atachier "to attach"); → system.

Râžmân, → system; nim-jodâ, from nim-semi- + jodâ "separate," from Mid.Pers. yut "separate, different;" Av. yuta- "separate, apart."

semidiameter
  نیم-ترامون   
nim-tarâmun

Fr.: demi-diamètre   

The angle at the observer subtended by the equatorial radius of the Sun, Moon, or a planet.

semi-; → diameter.

semiempirical
  نیمه‌آروینی   
nime-ârvini

Fr.: semi-empirique   

Describing an → equation or → formula that results from a → combination of → experiment and → theory.

semi-; → empirical.

semiempirical binding energy formula
  دیسول ِ نیمه‌آروینی ِ انرژی ِ بندش   
disul-e nime-ârvini-ye kâruž-e bandeš

Fr.: formule semi-empirique de l'énérgie de liaison   

Same as → Weizsacker formula.

semiempirical; → binding; → energy; → formula.

semilatus rectum
  نیم-تار ِ راست   
nim-târ-e râst

Fr.: demi-latus rectum   

Half the → latus rectum. For an ellipse, semilatus rectum has the expression l = b2/a, where a and b are semi-major and minor axes of the ellipse. It can also be expressed in terms of → eccentricity, e, as: l = a(1 - e2).

semi-; → latus rectum.

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