tâbeš-e forusorx (#)
Fr.: rayonnement infrarouge
That part of the → electromagnetic radiation lying beyond the red, between the radio and the visible regions of the → electromagnetic spectrum. The wavelengths range from about 0.8 → microns (μm) to about 1000 μm. See also: → near-infrared; → mid-infrared; → far-infrared; → submillimeter radiation.
inner Lindblad resonance (ILR)
bâzâvâyi-ye Lindblad-e daruni
Fr.: résonance de Lindblad interne
A → Lindblad resonance expressed by: Ωp = Ω - κ/m.
Fr.: élargissement instrumental
The broadening of a point source caused by the response functions of the telescope and the instrument used.
intensity of radiation
Fr.: intensité de rayonnement
The rate of emitted energy from unit surface area through unit solid angle. The radiation from a surface has different intensities in different directions.
interstellar radiation field
meydân-e tâbeš andaraxtari
Fr.: champ de rayonnement interstellaire
A global ionizing radiation in the → interstellar medium provided by various sources all together.
tâbeš-e yonandé (#)
Fr.: rayonnement ionisant
A photon that has enough energy to remove an electron from an atom or molecule, thus producing an ion and free electrons.
Fr.: éclairement énergétique
To expose something to → radiation.
1) tâbešdehi, tâbešgiri; 2) nurgostard
1) Exposure to any kind of radiation or atomic particles.
1) Tâbešdehi, tâbešgiri;, from tâbeš→ radiation + giri verbal noun of gereftan
"to take, seize" (Mid.Pers. griftan, Av./O.Pers. grab-
"to take, seize," cf.
Skt. grah-, grabh- "to seize, take," graha
"seizing, holding, perceiving," M.L.G. grabben "to grab,"
from P.Gmc. *grab, E. grab "to take or grasp suddenly;"
PIE base *ghrebh- "to seize"); dahi verbal noun of dâdan
"to give," Mid.Pers. dâdan "to give" (O.Pers./Av. dā-
"to give, grant, yield,"
dadāiti "he gives;" Skt. dadáti "he gives;"
Gk. tithenai "to place, put, set," didomi "I give;"
L. dare "to give, offer," facere "to do, to make;"
Rus. delat' "to do;" O.H.G. tuon, Ger. tun,
O.E. don "to do;" PIE base *dhe- "to put, to do").
Fr.: rayon isophotal
The size attributed to a galaxy corresponding to a particular level of → surface brightness. The reason is that galaxies do not have sharp edges.
1) A piece of equipment consisting of a series of bars or steps between
two upright lengths of wood, metal, or rope, used for climbing up or
M.E. laddre, O.E. hlæder "ladder, steps" (cognates: M.Du. ledere, O.H.G. leitara, Ger. Leiter), from PIE root *klei- "to lean," → incline.
šoâ'-e Larmor (#)
Fr.: rayon de Larmor
The radius of the circular motion of a → charged particle moving in a → uniform magnetic field. Same as → gyroradius, → radius of gyration, → cyclotron radius. The Larmor radius (rL) is obtained by equating the → Lorentz force with the → centripetal force: qvB = mv2/rL, which leads to rL = p/(ZeB), where p is → momentum, Z is → atomic number, e is the → electron charge, and B is → magnetic induction. The frequency of this circular motion is known as the → gyrofrequency.
law of non-contradiction
Fr.: principe de non-contradiction
Same as → principle of non-contradiction.
A metallic chemical element; symbol Pb (L. plumbum, of unknown origin). Atomic number 82; atomic weight 207.2; melting point 327.502°C; boiling point about 1,740°C. One of the oldest metals used by humanity, because of its relatively low melting point.
O.E. lead, from W.Gmc. *loudhom (cf. O.Fris. lad, M.Du. loot "lead," Ger. Lot "weight, plummet").
Sorb, from Mid.Pers. srub "lead;" Av. sru- "lead."
lakke-ye pišrow (#)
Fr.: tache de tête
In a → sunspot group, the first spot to form in the direction of rotation and the last to disappear. It is the largest, the strongest in magnetic intensity, and the closest to the solar equator among the group sunspots. See also → follower spot.
From M.E. leder(e), O.E. lædan "cause to go with one, lead," from W.Gmc. *laithjan (cf. O.S. lithan, O.N. liða "to go," O.H.G. ga-lidan "to travel," Goth. ga-leiþan "to go"); → spot.
Lakké, → spot; pišrow "leader, forerunner," from piš "in front, forward, before" (Mid.Pers. pêš "before, earlier;" O.Pers. paišiya "before; in the presence of") + row "going," present stem of raftan "to go, elapse, glide by, depart" (Mid.Pers. raftan, raw-, Proto-Iranian *rab/f- "to go; to attack").
niyâveš bé rowšanâyi
Fr.: adaptation à la lumière
The reflex adaptation of the eye to bright light, consisting of an increase in the number of functioning cones, accompanied by a decrease in the number of functioning rods; opposed to dark adaptation.
Fr.: résonance de Lindblad
A kinematic resonance hypothesized to explain the existence of galactic → spiral arms. It occurs when the frequency at which a star encounters the spiral → density wave is a multiple of its → epicyclic frequency. Orbital resonances occur at the location in the disk where Ωp = Ω ± κ/m, where Ωp is → pattern speed, κ → epicyclic frequency, and m an integer representing the number of spiral arms. The minus sign corresponds to the inner Lindblad resonance (ILR) and the plus sign to the outer Lindblad resonance (OLR). The corotation resonance corresponds to Ωp = Ω. In general, the Lindblad resonances are defined for two spiral arms (m = 2), and low order. There are other less important resonances corresponding to higher m values. These resonances tend to increase the object's orbital eccentricity and to cause its longitude of periapse to line up in phase with the perturbing force. Lindblad resonances drive spiral density waves both in galaxies (where stars are subject to forcing by the spiral arms themselves) and in Saturn's rings (where ring particles are subject to forcing by Saturn's moons).
After the originator of the model, Bertil Lindblad (1895-1965), a Swedish astronomer, who made important contributions to the study of the rotation of the Galaxy; → resonance.
Fr.: élargissement de raie
A widening of → spectral lines due to any of several factors, including the → Doppler broadening, → instrumental broadening, → microturbulence, → pressure broadening, → rotational broadening, the → Stark effect, and the → Zeeman effect.
linear electric quadrupole
cahârqotbe-ye barqi-ye xatti
Fr.: quadrupôle électrique linéaire
A system of three charges +q, -2q, and +q, arranged along a line to form an axial quadrupole. The → electric potential V due to a linear quadrupole varies as 1/r3, whereas the → electric intensity E varies as 1/r4.
1) bâr; 2) bâr kardan (#)
Fr.: 1) charge; 2) charger
1) Something that is borne or carried.
From M.E. lode, originally the same word as lode, from O.E. lāad "way, course, carrying;" cf. O.N. leith "way, route," O.H.G. leita "procession."
Bâr kardan "to load," composite verb from bâr "load, charhe, burden," (Mid.Pers. bâr, from O.Pers./Av. base bar- "to bear, carry;" Mod.Pers. bordan "to carry;" L. brutus "heavy, dull, stupid, brutish;" Skt. bhara- "burden, load," bharati "he carries;" Gk. baros "weight;" Mod.Pers. gerân "heavy;" Skt. guru; L. gravis; PIE *gwere- "heavy," *bher- "carry, give birth") + kardan "to do, to make" (Mid.Pers. kardan; O.Pers./Av. kar- "to do, make, build;" Av. kərənaoiti "he makes;" cf. Skt. kr- "to do, to make," krnoti "he makes, he does," karoti "he makes, he does," karma "act, deed;" PIE base kwer- "to do, to make").