An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

   Homepage   
   


A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

<< < "no abs acc ads amb ann arg ato B-m bla bro cat Che co- col com com con con con cor cro dec def dep dif dil dis dis dur eje emi equ evo exp fab fis fra fus geo gra gra har Huy ima ind inf ins int int ion jum law lin low mag mat mic Moo nec non nuc obs opp Ori par per per phy ple pop pre pro pro pul rad rad Ray rec reg rep Ric rot Sch sec Sha soc spe sta ste sub syn the tot tri uni Ven vis wor > >>

Number of Results: 1965 Search : ion
linear acceleration
  شتاب ِ خطی   
šetâb-e xatti

Fr.: accélération linéaire   

The rate of change of the → linear velocity with time. It is defined by the expression Δvt and is equal to the → first derivative of the → linear velocity.

linear; → acceleration.

linear approximation
  نزدینش ِ خطی   
nazdineš-e xatti

Fr.: approximation linéaire   

Taking the first term in the Taylor series as an approximation to a mathematical function at a given point. → first approximation.

linear; → approximation.

linear correlation
  هم‌باز‌آنش ِ خطی   
hambâzâneš-e xatti

Fr.: corrélation linéaire   

A measure of how well data points fit a straight line. When all the points fall on the line it is called a perfect correlation. When the points are scattered all over the graph there is no correlation.

linear; → correlation.

linear differential equation
  هموگش ِ دگرسانه‌ای ِ خطی   
hamugeš-e degarsâne-yi-ye xatti

Fr.: équation différentielle linéaire   

An equation in which the → dependent variable y and all its differential coefficients occur only in the first degree. A linear differential equation of → order  order n has the form:
fn(x)y(n) + fn-1(x)y(n-1) + ... + f1(x)y' + f0(x)y = Q(x),
where f0(x), f1(x), ..., fn(x) and Q(x) are each continuous functions of x defined on a common interval I and fn(x)≠ 0 in I. A linear differential equation cannot have, for example, terms such as y2 or (y')1/2. See also: → homogeneous linear differential equation; → nonhomogeneous linear differential equation.

linear; → differential; → equation.

linear equation
  هموگش ِ خطی   
hamugeš-e xatti

Fr.: équation linéaire   

An equation composed of first degree variables and representing a straight line.

linear; → equation.

linear function
  کریای ِ خطی   
karyâ-ye xatti

Fr.: fonction linéaire   

A function expressed by a → first degree equation that can be graphically represented in the → Cartesian coordinate plane by a → straight line.

linear; → function.

linear perturbation theory
  نگره‌ی ِ پرتورش ِ خطی   
negare-ye partureš-e xatti

Fr.: théorie de perturbation linéaire   

Assumption that the variations in the plasma parameters, due to the presence of waves, are small (to the first order) as compared to the undisturbed parameters. This makes it possible to linearize equations by dropping out second order (and higher) nonlinear terms.

linear; → perturbation; → theory.

linear polarization
  قطبش ِ خطی   
qotbeš-e xatti (#)

Fr.: polarisation linéaire   

Of an electromagnetic radiation, a → polarization in which the electric vibrations are confined to one plane along the direction of propagation. Also called → plane polarization. See also → circular polarization.

linear; → polarization.

linear regression
  وایازی ِ خطی   
vâyâzi-ye xatti

Fr.: regression linéaire   

In statistics, a regression method that establishes a linear relationship between two random variables.

linear; → regression.

linearization
  خطش، خطانش   
xatteš, xattâneš

Fr.: linéarisation   

A process of reduction to linear form by appropriate change of variables or by approximation.

Verbal noun of → linearize.

linearized differential equation
  هموگش ِ دگرسانه‌ای ِ خطی   
hamugeš-e degarsâneyi-ye xatti

Fr.: équation différentielle linéarisée   

A differential equation that has been derived from an original nonlinear equation.

Linearized, p.p. of → linearize; → differential; → equation.

lion
  شیر   
šir (#)

Fr.: lion   

A large, usually tawny-yellow cat, Panthera leo, native to Africa and southern Asia, having a tufted tail and, in the male, a large mane (dictionary.com).

M.E., from O.Fr., variant of leon, from L. leon- (stem of leo), from Gk. leon.

Mid.Pers. šagr "lion;" cf. Parth. šarg; Sogd. šarγu "lion;" its O.Pers. and Av. forms are not extant. Šir may be cognate with Skt. kēsarin- "lion; literally maned," from kēsar- "mane;" PIE *kaisar- "mane; hairs." If so, šir could be related to PIE *kaisaraka-, provided that the the initial *kai- is dropped and *saraka- has transformed in *sarg, šarg, šir.

liquefaction
  آوش   
âveš

Fr.: liquéfaction   

1) The act or process of liquefying or making liquid.
2) The state of being liquefied.

liquefy; → -tion.

local position invariance
  ناورتایی ِ نهش ِ محلی   
nâvartâyi-ye neheš-e mahali

Fr.: invariance de position locale   

Einstein equivalence principle.

local; → position; → invariance.

localization
  محل‌گیری   
mahal giri (#)

Fr.: localisation   

The condition of the wave-function of an electron if it is confined to a small region of a large system rather than being extended through the system.

Verbal noun of → localize.

logarithmic extinction
  خاموشی ِ لگاریتمی   
xâmuši-ye logâritmi

Fr.: extinction logarithmique   

Same as → reddening coefficient.

logarithmic; → extinction.

lognormal distribution
  واباژش ِ لگاریتمی-هنجارور   
vâbâžeš-e logâritmi-hanjârvar

Fr.: distribution logarithmico-normale   

A → probability distribution in which the natural logarithm (logX) of the → random variable (X) has a → Gaussian distribution.

logarithm; → normal distribution.

Lorentz contraction
  ترنگش ِ لورنتز   
terengeš-e Lorentz

Fr.: contraction de Lorentz   

The decrease in the length of a body moving in the direction of its length as measured by an observer situated in that direction. The shortening factor is [1 - (v/c)2]1/2, where v is the relative velocity and c light speed.

Lorentz; → contraction.

Lorentz transformation
  ترادیس ِ لورنتز   
tarâdis-e Lorentz

Fr.: transformation de Lorentz   

A set of linear equations that expresses the time and space coordinates of one → reference frame in terms of those of another one when one frame moves at a constant velocity with respect to the other. In general, the Lorentz transformation allows a change of the origin of a coordinate system, a rotation around the origin, a reversal of spatial or temporal direction, and a uniform movement along a spatial axis. If the system S'(x',y',z',t') moves at the velocity v with respect to S(x,y,z,t) in the positive direction of the x-axis, the Lorentz transformations will be: x' = γ(x - vt), y' = y, z' = z, t' = γ [t - (vx/c2)], where c is the → velocity of light and γ = [1 - (v/c)2]-1/2. For the special case of velocities much less than c, the Lorentz transformation reduces to → Galilean transformation.

Lorentz; → transformation.

low resolution
  که‌واگشود   
keh vâgošud

Fr.: faible résolution   

The quality of an instrument that lacks sufficient resolution for a specific observation. This is a relative quality, but presently a resolution below about 1 arcsecond.

low; → resolution.

<< < "no abs acc ads amb ann arg ato B-m bla bro cat Che co- col com com con con con cor cro dec def dep dif dil dis dis dur eje emi equ evo exp fab fis fra fus geo gra gra har Huy ima ind inf ins int int ion jum law lin low mag mat mic Moo nec non nuc obs opp Ori par per per phy ple pop pre pro pro pul rad rad Ray rec reg rep Ric rot Sch sec Sha soc spe sta ste sub syn the tot tri uni Ven vis wor > >>