An Etymological Dictionary of Astronomy and Astrophysics

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory



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Number of Results: 76 Search : function
source function
  کریای ِ خن   
karyâ-ye xan

Fr.: fonction source   

For a radiating material, the ratio of emissivity to opacity.

source; → function.

spline function
  کریای ِ اسپلین   
karyâ-ye splin

Fr.: fonction spline   

A function consisting of several segments, usually → polynomials, joined smoothly together at specific points with an explicitly stated degree of accuracy. Spline functions are used to approximate a given function on an interval.

From East Anglian dialect, maybe related to O.E. splin and to modern splint. A spline was originally a slat or a thin strip of wood. A later meaning was "a long, thin, flexible strip used as a guide for drawing arcs of curves;" → function.

stellar creation function
  کریای ِ آفرینش ِ ستارگان   
karyâ-ye âfarineš-e setâregân

Fr.: fonction de création stellaire   

The number of stars born per unit area in the mass range log M to log M + d log M during the time interval t to t + dt. The integration of the creation function over time gives the → present-day mass function (Miller & Scalo, 1797, ApJSS 41, 513).

stellar; → creation; → function.

step function
  کریای ِ پله‌ای   
karyâ-ye pelle-yi

Fr.: fonction échelon   

Math.: A function f of a real variable defined on an interval [a,b] so that [a,b] can be divided into a finite number of sub-intervals on each of which f is a constant. The graph of a step function is a series of line segments resembling a set of steps.

Step, from M.E. steppen, O.E. steppan; cf. Du. stap, O.H.G. stapfo, Ger. stapfe "footprint;" → function.

Karyâ, → function; pellé "stair, step;" Mid.Pers. pylg "step," pillagân "steps, staircase;" from *palak, from *padak, from pad-, → foot, + relation suffix -ak.

total function
  کریای ِ هماک   
karyâ-ye hamâk

Fr.: fonction totale   

A function whose value is defined for all possible input values.

total; → function.

transcendental function
  کریای ِ ترا-فرازنده   
karyâ-ye tarâfarâzandé

Fr.: fonction transcendante   

A function which is not → algebraic. For example y = cosx, y = 10xx.

transcendental; → function.

transfer function
  کریای ِ تراوژ   
karyâ-ye tarâvaž

Fr.: fonction de transfert   

The mathematical relationship between the output of a control system and its input: for a linear system, it is the Laplace transform of the output divided by the Laplace transform of the input under conditions of zero initial-energy storage.

transfer; → function.

transition function
  کریای ِ گذرش   
karyâ-ye gozareš

Fr.: fonction de transition   

The → probability of finding the → Universe in a → state labelled X2 at a time t2, if it was in a state X1 at an earlier time t1.

transition; → function.

trigonometric function
  کریای ِ سه‌برسنجیک   
karyâ-ye sebarsanjik

Fr.: fonction circulaire, ~ trigonomtérique   

A function of an angle, one of six functions (sine, cosine, tangent, cotangent, secant, and cosecant) that represent ratios of sides of right triangles. Also called circular function.

trigonometric; → function.

truth function
  کریای ِ راستینی   
karyâ-ye râstini

Fr.: fonction de vérité   

A → total function from → truth values to truth values (a sequence of truth values).

truth; → function.

unbounded function
  کریای ِ بیکران   
karyâ-ye bikarân

Fr.: fonction non bornée   

The function y = f(x) in a given range of the argument x if there is no number M such that for all values of x in the range under consideration the inequality | f(x) | ≤ M will be fulfilled. → bounded function.

unbound; → function.

vector function
  کریای ِ برداری   
karyâ-ye bordâri

Fr.: fonction vectorielle   

A function whose value at each point is n-dimensional, as compared to a scalar function, whose value is one-dimensional.

vector; → function.

visibility function
  کریای ِ دیاری، ~ پدیداری   
karyâ-ye diyâri, ~ padidâri

Fr.: fonction de visibilité   

The Fourier transform of a source's brightness distribution, weighted by the characteristics of the interferometer's antennas.

visibility; → function.

wave function
  کریای ِ موج   
karyâ-ye mowj

Fr.: fonction d'onde   

In → quantum mechanics, the function of space and time that satisfies → Schrodinger equation. The square of the modulus of its amplitude at any point represents the probability of finding a particle there.

wave; → function.

window function
  کریای ِ روزنه   
karyâ-ye rowzané

Fr.: fonction fenêtre   

A function whose value is zero outside a given interval. Applications of window functions include signal filtering and spectral analysis. The various types of windw functions include: → rectangular window, cosine window, triangular window, Gaussian window, Hanning window, and so on.

window; → function.

work function
  کریای ِ کار   
karyâ-ye kâr

Fr.: travail d'extraction   

The least amount of energy required to remove an electron from the surface of a solid, to a point just outside the solid where the electron has zero kinetic energy. See also → photoelectric effect.

work; → function.

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