Fr.: quantité de mouvement linéaire
The product of an object's → mass and → velocity. It is a → vector and points in the same direction as the velocity vector. Linear momentum is distinguished from → angular momentum. When there is no opportunity for confusion, usually the term momentum is used instead of linear momentum.
linear perturbation theory
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.
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.
barnâme-sâzi-ye xatti (#)
Fr.: programmation linéaire
A procedure for finding the maximum or minimum of a → linear function where the → arguments are subject to linear → constraints. For problems involving more than two variables or problems involving a large number of constraints, solution methods used are those that are adaptable to computers. A well-known such → algorithm is the → simplex method.
Fr.: regression linéaire
In statistics, a regression method that establishes a linear relationship between two random variables.
Fr.: taille linéaire
The real, physical size, as opposed to angular size.
Fr.: système linéaire
Physics: A → dynamical system whose evolution is a linear process. If a change in any variable at some initial time produces a change in the same or some other variable at some later time, twice as large a change at the same initial time will produce twice as large a change at the same later time.
Fr.: vitesse linéaire
The rate of change of the position of an object that is traveling along a straight path. In other words, the velocity of an object when its moving direction is not changing. For a given → angular velocity (ω), the linear velocity v of the particle is directly proportional to the distance of the particle from the center of the circular path: v = ω ×r.
The property, condition, or state of being linear.
A process of reduction to linear form by appropriate change of variables or by approximation.
Verbal noun of → linearize.
To make linear; give linear form to.
linearized differential equation
hamugeš-e degarsâneyi-ye xatti
Fr.: équation différentielle linéarisée
A differential equation that has been derived from an original nonlinear equation.
In a manner characterized by first-degree algebraic terms.
Adverb of → linear.
Fr.: linéairement dépendant
A set of objects x1, x2, ..., xn (→ vectors, → matrices, → polynomials, etc.) on a given set if there is a linear combination of them: a1x1 + a2x2 + ... + anxn, which is zero, but at least one of the coefficients is non-zero. For example the binomials (2x + y) and (6x + 3y) are linearly dependent, since 3(2x + y) - (6x + 3y) = 0.
Fr.: linéairement indépendant
1) A set of objects x1, x2, ..., xn
(→ vectors, → matrices,
→ polynomials, etc.) if it si not
→ linearly dependent.
linearly polarized light
nur-e qotbide-ye xatti
Fr.: lumière polarisée linéairement
Light exhibiting → linear polarization.
A type of galactic nucleus that is defined by its spectral line emission. The lines are very weak, the most prominent ones being from low ionization states (such as [O II], [N II], [S II] and [OI]). There is so far no generally accepted interpretation of the spectra of liners. It is likely that galaxies of different histories may have their nuclei with liner-type spectra. → retired galaxy.
Short for → Low-Ionization Nuclear Emission-line Region. The term liner was first introduced by T. M. Heckman (1980, A&A 87, 152).
xatt-pahnâ (#), pahnâ-ye xatt (#)
Fr.: largeur de raie
1) The range of frequencies or wavelengths over which
radiations are absorbed or emitted in a transition between a specific
pair of atomic energy levels. The full width is determined between
half-power points of the line.
Fr.: variable linguistique
zabânik (#), zabânšenâsi (#)