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: 12937 Search : far
laminar
  ورقه‌ای   
varaqe-yi

Fr.: laminaire   

Composed of, or arranged in, laminae, sheets.

lamina + → -ar.

laminar boundary layer
  لایه‌ی ِ کرانی ِ ورقه‌ای   
lâye-ye karâni-ye varaqe-yi

Fr.: Couche limite laminaire   

In a fluid flow, layer next to a fixed boundary. The fluid velocity is zero at the boundary but the molecular viscous stress is large because the velocity gradient normal to the wall is large. → turbulent boundary layer.

laminar; → boundary; → layer.

laminar flow
  تچان ِ ورقه‌ای   
tacân-e varaqe-yi

Fr.: écoulement laminaire   

A flow in which the particles of fluid are moving orderly, and in which adjacent layers or laminas glide smoothly over another with little mixing between them. A laminar flow may rapidly transform into a → turbulent flow for large → Reynolds numbers.

laminar; → flow.

laminar sublayer
  زیرلایه‌ی ِ ورقه‌ای   
zirlâye-ye varaqe-yi

Fr.: sous-couche laminaire   

A layer in which the fluid undergoes smooth, nonturbulent flow. It is found between any surface and a turbulent layer above.

laminar; sublayer, from → sub- + → layer.

lamp
  لامپ، چراغ   
lâmp (#), cerâq (#)

Fr.: lampe   

Any of various devices producing artificial light, as by electricity, gas, or oil.

From O.Fr. lampe, from L. lampas, from Gk. lampas "torch, lamp, beacon, meteor, light," from lampein "to shine," from PIE base *lap- "to shine" (cf. Lith. lope "light," O.Ir. lassar "flame").

Lâmp, loanword from Fr., as above.
Cerâq "lamp" (variants Kurd. cira, cerâh, Laki cerâx, Zâzâ cərâ, cərâx "lamp, candle," Shughni cirow, cirâw, cərêγ "candle, lamp"); Mid.Pers. cirâq "lamp," related to foruq "light," afruxtan "to light, kindle," rowšan "bright, clear," rowzan "window, aperture;" ruz "day;" Mid.Pers. rôšn "light; bright, luminous," rôc "day;" O.Pers. raucah-rocânak "window;" O.Pers. raocah- "light, luminous; daylight;" Av. raocana- "bright, shining, radiant;" akin to Skt. rocaná- "bright, shining," roka- "brightness, light;" Gk. leukos "white, clear;" L. lux "light" (also lumen, luna); Fr. lumière; E. light; O.E. leoht, leht, from W.Gmc. *leukhtam (cf. O.Fris. liacht, M.Du. lucht, Ger. Licht), from PIE *leuk- "light, brightness."

land
  خشکی، زمین   
xoški (#), zamin (#)

Fr.: terre   

Any part of the earth's surface not covered by a body of water.

M.E., from O.E. land, lond, "ground, soil, territory;" PIE base *lendh- "land, heath" (cf. O.N., O.Fris. Du., Ger., Goth. land; O.Ir. land; Welsh llan "enclosure, church," Breton lann "heath," source of Fr. lande; O.C.S. ledina "waste land, heath," Czech lada "fallow land").

Xoški, from xošk, → dry, + noun suffix -i; zamin "land, → earth."

land breeze
  نسیم ِ خشکی   
nasim-e xoški (#)

Fr.: brise de terre   

A coastal breeze blowing from land to sea after sunset, caused by the temperature difference when the sea surface is warmer than the adjacent land. The warmer air above the water continues to rise, and cooler air from over the land replaces it, creating a breeze.

Land, → lander; → breeze.

Xoški "land," from xošk "dry;" Mid.Pers. xušk "dry;" O.Pers. uška- "mainland;" Av. huška- "dry;" cf. Skt. śuska- "dry, dried out;" Gk. auos "dry, dried up;" O.E. sēar "dried up, withered;" Lith. sausas "dry, barren."

Landau damping
  میرایی ِ لانداؤ   
mirâyi-ye Landau

Fr.: amortissement de Landau   

The process wherein a → plasma gains energy at the expense of the → Langmuir wave. In the presence of the → Landau resonance, the particles in resonance moving slightly faster than the wave lose energy, while those moving slightly slower will gain energy. Since the Maxwellian distribution is decreasing with velocity, in a Maxwellian plasma, near the Landau resonance, there are more particles at lower velocities than at higher velocities. Also called collisionless damping.

Lev Landau (1908-1968), a prominent Soviet physicist, 1962 Nobel Prize in Physics for his development of a mathematical theory of → superfluidity; → damping.

Landau level
  تراز ِ لانداؤ   
tarâz-e Landau

Fr.: niveau de Landau   

The → energy level which can be occupied by a → free electron in a → magnetic field.

Landau damping; → level.

Landau resonance
  باز‌آوایی ِ لانداؤ   
bâzâvâyi-ye Landau

Fr.: résonance de Landau   

For parallel propagating → electrostatic waves in a → plasma, the → resonance which occurs when the particle velocity equals the parallel phase velocity of the wave.

Landau damping; → damping.

Landé factor
  کروند ِ لانده   
karvand-e Landé

Fr.: facteur de Landé   

The constant of proportionality relating the separations of lines of successive pairs of adjacent components of the levels of a spectral multiplet to the larger of the two J-values for the respective pairs. The interval between two successive components J and J + 1 is proportional to J + 1.

After Alfred Landé (1888-1976), a German-American physicist, known for his contributions to quantum theory; → facteur.

lander
  زمین‌نشین   
zamin-nešin

Fr.: atterrisseur   

A → space probe designed to land on a → planet or other solid → celestial body.

land; → -er.

Lane-Emden equation
  هموگش ِ لین-امدن   
hamugeš-e Lane-Emden

Fr.: équation de Lane-Emden   

A second-order nonlinear → differential equation that gives the structure of a → polytrope of index n.

Named after the American astrophysicist Jonathan Homer Lane (1819-1880) and the Swiss astrophysicist Robert Emden (1862-1940); → equation

Langevin equation
  هموگش ِ لانژون   
hamugeš-e Langevin

Fr.: équation de Langevin   

Equation of motion for a weakly ionized cold plasma.

Paul Langevin (1872-1946), French physicist, who developed the theory of magnetic susceptibility of a paramagnetic gas; → equation.

Langmuir wave
  موج ِ لانگموییر   
mowj-e Langmuir

Fr.: onde de Langmuir   

A disturbance of a → plasma in the form of a longitudinal, → electrostatic wave that propagates in the plasma due to variations in the plasma's electron density. More specifically, Langmuir waves are collective oscillations of inhomogeneous bunches of electrons displaced from their natural equilibrium, in which the inertia of the relatively massive ions serves to establish an electrostatic restoring force that tries to bring the electrons back to their equilibrium positions. → Landau damping causes dissipation of Langmuir waves as the electrons are either accelerated or decelerated so as to be in resonance with the phase velocity of the waves themselves.

Irving Langmuir (1881-1957), American chemist and physicist, Nobel Prize in Chemistry 1932; → wave.

Langmuir-Hinshelwood mechanism
  ساز-و-کار ِ لنگموییر-هینشلوود   
sâzokâr-e Langmuir-Hinshelwood

Fr.: mécanisme de Langmuir-Hinshelwood   

Suggested by Irving Langmuir (1881-1957) in 1921, who was awarded the Nobel Prize in Chemistry in 1932 for his work in surface chemistry. And further developed by Cyril Hinshelwood (1897-1967) in 1926, who received the Nobel Prize in Chemistry in 1956 for his researches into the mechanism of chemical reactions.

language
  زبان   
zabân (#)

Fr.: langue   

Any means of conveying or communicating ideas; specifically, human speech.

M.E., from O.Fr. langage, from L. lingua "tongue; speech, language."

Zabân "tongue; language," from Mid.Pers. uzwân "tongue; language;" O.Pers. hzanm, hizânam "tongue," Av. hizuua-, hizū- "tongue;" cf. Skt. jivhā- "tongue;" L. lingua "tongue, speech, language;" O.Ir. tenge; Welsh tafod; Lith. liezuvis; O.C.S. jezyku; M.Du. tonghe; Du. tong; O.H.G. zunga; Ger. Zunge; Goth. tuggo; PIE base *dnghwa-.

language paleontology
  پارین‌شناسی ِ زبانی   
pârinšenâsi-ye zabâni

Fr.: paléontologie linguistique   

An approach in which terms reconstructed in the → proto-language are used to make inferences about its speakers' culture and environment.

language;→ paleontology.

Laniakea supercluster
  ابرخوشه‌ی ِ لانیاکءا   
abarxuše-ye Laniakea

Fr.: superamas Laniakea   

A → supercluster of galaxies that includes our → Local Group and about 300 to 500 known → galaxy clusters and groups. Also called → Local Supercluster. If approximated as round, it has a diameter of 12,000 km s-1 in units of the → cosmic expansion or 160 megaparsecs, and encompasses about 1017 → solar masses. Our Local Group lies toward the outer regions of Laniakea. Its main components are the four previously known superclusters: → Virgo supercluster (the part where the → Milky Way resides), Hydra-Centaurus Supercluster (including the → Great Attractor, Antlia Wall, known as Hydra Supercluster, → Centaurus supercluster), Pavo-Indus Supercluster, and Southern Supercluster (including Fornax Cluster, Dorado and Eridanus clouds). The most massive galaxy clusters of Laniakea are Virgo, Hydra, Centaurus, Abell 3565, Abell 3574, Abell 3521, Fornax, Eridanus, and Norma. The Laniakea supercluster was discovered by Tully et al. (2014, Nature 513, 71).

From the Hawaiian words lani "heaven," and akea "spacious, immeasurable;" → supercluster.

lanthanide
  لانتانید   
lântânid (#)

Fr.: lanthanide   

Any of the series of 15 consecutive → chemical elements in the → periodic table from → lanthanum to lutetium (→ atomic numbers 57 to 71 inclusive). The atoms of these metals have similar configurations and similar physical and chemical properties. They are grouped apart from the rest of the elements in the → Periodic Table because they all behave in a similar way in chemical reactions. Also called → rare-earth element. International Union of Pure and Applied Chemistry currently recommends the name lanthanoid rather than lanthanide.

From the chemical element → lanthanum.

<< < -es -iv -ti 217 A s abe abs abs acc acc Ach act act ADa adi adv aff age Alc Alf ali all alp alt ama amp ana ang ang ann ano ant ant ape apo app aps arc Arg arm art ass ast ast ast atm ato att aur aut axi B-t Bai Bal bar bar Be bed Bes BHB bif bim bin Bio bis bla ble blu bod Bol bor bou bra Bre bro Bul cag cal can Can car Car Cas cat CCD cel cen Cet cha cha che che chr cir cir cit cla clo clo clu Coa coe coh col Col col com com com com com com com com com con con con con con con con con con con con coo cor cor cor cos cos cos cou cou cra cri cro cry cul cur cyc D r dar dat day dea dec dec dec def def deg del den dep des det deu dex dif dif dif dim dip dir dis dis dis dis dis div dom dos dou dri Dum dus dyn dyn ear eas ecl Edd eff Ein eje ele ele ele ele eli emb emi Enc ene ens eph epo equ equ eru eth Eul eve evo exc exc exi exo exp exp ext ext fab fai Fan Fea fem fer fie fil fir fis fla flo flu foc for for Fou fra fre fre fro fun G r Gal gal gam gas Gau gel gen geo geo geo Gho gla goa gra gra gra gra gre Gre gro gyr had hal har har HD Hea Hel hel Her her hid hig Hip hom hor hot Hub Hub hun hyd hyd hyg Hyp ice ide ima imm imp imp inc ind ind ine inf inf inf ini ins ins int int int int int int int int int inv ion iro ise iso iso Jab jet Jov Jur Kel Kep kil kit Kui Lag lam lan Lar Lat law lea lem lep Li- lig lim lin lin lio lit loc lod lon Lor low Lum lun Lup Lyn mac mag mag mag mag mag mai man mar mas mas mat Max mea mec mel mer mes met met met mic mid mil Min mir mix mod mol mom Moo mor mov mul mur nab nar nat neb neg nes neu New New nig nod non non non Nor nua nuc nul Nun OBC obl obs occ oct off Ohm on- ope opp opt opt orb orb org Ori ort Ost out ove p m Pal par par par par Pas pat Peg Peo per per per per per pha Phe pho pho pho phy pin pla pla pla pla pla plu poi pol pol Pol pol pos pos pot pra pre pre pre pre pri pri pro pro pro pro pro pro pro pse pul Pup Qua qua qua qua que rac rad rad rad rad rad rad ran rap ray rea rea rec rec red red ref ref reg rel rel rel ren res res res res ret rev Ric rig rin roc roo rot rot rur Sac sal sat sca sca Sch sci Scu sec sec Sed sel sem sen Ser Sey Sha she sho sid sig sim sin sip ske sli smo soc sol sol sol sol sol sou spa spa spe spe spe spe Spi spi spo squ sta sta sta sta Ste ste ste sto str str str sub sub sub sun sup sup sup sup sur sus sym syn T-s tar Tei tem ter tes the the the the thi thr tid tim Tis Too Tor tra tra Tra tra tra tri tri tru Tul tur Tyc Typ ult unb und uni uni unr upp Urs vac van Var veg Ven ver vib vio vir vis vol VY war wat wav WC8 Web wes whi win WN1 wob wri X-r yoc zen Zhe > >>