An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 373
nuclear spin
  اسپین ِ هسته‌ای   
espin-e haste-yi

Fr.: spin nucléaire   

The total → angular momentum of a → nucleus, represented by symbol I. The nucleus, which is composed of neutrons and protons, acts as if it is a single entity which has intrinsic angular momentum. The nuclear spin depends on the → mass number; if the mass number is odd then the nucleus has half-integer spin like the electron while if the nucleus has even mass number then its spin will be integer spin.

nuclear; → spin.

nuclear statistical equilibrium (NSE)
  ترازمندی ِ آماری ِ هسته‌ای   
tarâzmandi-ye âmâri-ye haste-yi

Fr.: équilibre statistique nucléaire   

In → nucleosynthesis models, the condition in which all nuclear species are in equilibrium under exchange of → protons and → neutrons. Matter in nuclear statistical equilibrium is characterized by a large abundance of iron peak nuclei. In such equilibria abundance of each nuclide can be calculated from repeated application of → Saha equation.

nuclear; → statistical; → equilibrium.

nuclear time scale
  مرپل ِ زمانی ِ هسته‌ای   
marpel-e zamâni-ye haste-yi

Fr.: échelle de temps nucléaire   

The time required for a star to exhaust its hydrogen (H) supply in → nuclear fusion. The nuclear time scale is given by the relation t = E/L, where E is the total nuclear energy that can be generated by a star and L is the stellar → luminosity. Assuming that the end point of fusion is → iron (Fe), the → atomic mass difference between H and Fe is Δm = 0.008 mH. Therefore, the maximum amount of energy a star with a hydrogen mass M can release is Δ M = 0.008 Mc2. The nuclear time scale is then: t = 0.008 c2M/L. However, stars use up only a fraction of their hydrogen supply, because only the inner part of the star is hot enough for fusion. For example, the Sun will spend only about 10% of its hydrogen supply before evolving into a → red giant. In other words, the solar life time on the → main sequence is about 1010 years.

nuclear; → time; → scale.

nuclear transition
  گذرش ِ هسته‌ای   
gozareš-e haste-yi

Fr.: transition   

A change in the → energy level or state of an atomic → nucleus involving a → quantum of energy.

nuclear; → transition.

nuclear transmutation
  تراموتش ِ هسته‌ای   
tarâmuteš-e haste-yi

Fr.: transmutation nucléaire   

The changing of atoms of one element into those of another by suitable nuclear reactions.

nuclear; → transmutation.

nuclear waste
  آخال ِ هسته‌ای   
âxâl-e haste-yi (#)

Fr.: déchets nucléaires   

A particular type of radioactive waste that is produced as part of the nuclear fuel cycle. These include extraction of uranium from ore, concentration of uranium, processing into nuclear fuel, and disposal of byproducts.

nuclear; → waste.


Fr.: nucléon   

A constituent of the atomic nucleus, i.e. a proton or a neutron.

From nucle(us), → nucleus, + -on a suffix used in the names of subatomic particles, probably extracted from → ion.

Haston, from hast(é)nucleus + -on, as above.


Fr.: nucléonique   

The practical applications of nuclear physics, and the techniques associated with those applications.

From → nucleon + → -ics.


Fr.: nucléosynthèse   

The process by which → nuclear reactions at very high temperatures and pressures produce the various → chemical elements of the → periodic table, either in the → Big Bang or in stellar interiors. See also → primordial nucleosynthesis, → stellar nucleosynthesis, → explosive nucleosynthesis.

From nucleo-, combining form of → nucleus + → synthesis.

Haste-handâyeš, from hasténucleus + handâyešsynthesis.


Fr.: nucléosynthétiser   

Produce through → nucleosynthesis.

nucleosynthesis; → -ize.


Fr.: nucléosynthétique   

Of, pertaining to, proceeding by, or involving → nucleosynthesis.

Adj. of → nucleosynthesis.

nucleosynthetic era
  دوران ِ هسته‌هندایش   
dowrân-e haste-handâyi

Fr.: ère nucléosynthétique   

The era following the leptonic era, between 1 second and 1000 seconds after the Big Bang, when neutrons were abundant and helium and deuterium were synthesized.

nucleosynthetic; → era.

nucleosynthetic process
  فراروند ِ هسته‌هندایشی   
farâravand-e haste-handâyeši

Fr.: processus nucléosynthétique   

A process involving → nucleosynthesis, such as → r-process and → r-process.

nucleosynthetic; → process.

hasté (#)

Fr.: noyau   

1) Core of an atom, where most mass and all positive charge is concentrated. It consists of protons and neutrons.
2) Of a comet, the stellar-appearing frozen core, containing most of the cometary mass, in the head of a comet.

From L. nucleus "kernel," from nucula "little nut," diminutive of nux "nut," from PIE *knu(k) "lump" (cf. M.Ir. cnu, Welsh cneuen, M.Bret. knoen "nut," O.N. hnot, O.E. hnutu "nut").

Hasté, variants asté "kernel, fruit stone," ostoxân "bone," from Mid.Pers. astak "fruit stone, bone," ast "bone;" Av. ast- "bone;" cf. Skt. asthi- "bone;" Gk. osteon; L. os; Hittite hashtai-; PIE base *os-.


Fr.: nucléide   

A species of atom characterized by the constitution of its nucleus, i.e. by the numbers of protons and neutrons it contains.

From nucl(eo), → nucleus, + -ide, from Gk. eidos "shape."

Hastevâr, from hasté, → nucleus, + -vâr a suffix meaning "resembling, like," from Mid.Pers. -wâr, Av. -vara, -var, cf. Skt. -vara.

  ۱) نول؛ ۲) نولیدن   
1) nul; 2) nulidan

Fr.: 1) nul; 2) rendre nul   

1a) General: Being or amounting to nothing; nil; nonexistent; without value, effect, or significance.
1b) Math.: Of a set, empty. Of measure zero.
1c) Electronics: A point of minimum signal reception, as on a radio direction finder or other electronic meter.
2) To make null; cancel.

From M.Fr. nul, from L. nullus "not any, none," from ne- "not, no" → non- + illus "any," dimunitive of unus "one."

Nul, from na-, → non-, + -ul a variant of the Pers. suffix → -al. Nulidan, infinitive from nul.

null geodesic
  کهین‌ره ِ نول   
kehinrah-e nul

Fr.: géodésique nulle   

1) The path taken by a light ray in a curved → space-time just as a → timelike geodesic describes the path of a material particle.
2) A → geodesic of length zero.

null; → geodesic.

null hypothesis
  انگاره‌ی ِ نول   
engâre-ye nul

Fr.: hypothèse nulle   

Statistics: The assumption of the absence of a particular pattern in a set of data. The null hypothesis, denoted by H0, is put forward to be rejected in order to support an → alternative hypothesis.

null; → hypothesis.

null lens
  عدسی ِ نول   
adasi-ye nul


A lens used in the optical testing of an aspheric surface. It converts a spherical wavefront into one that precisely matches the surface under test. When the wavefront is reflected from that surface, it reverses its path and, if the surface is perfect, results in a perfect emerging spherical wavefront, which is easily evaluated.

null; → lens.

null matrix
  ماتریس ِ نول   
mâtris-e nul

Fr.: matrice nulle   

An m × n matrix whose elements are all zeros. Also known as zero matrix.

null; → matrix.

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