Fr.: constante de Dirac
Fr.: équation de Dirac
The equation that describes the behavior of an electron in a way that combines the requirements of quantum mechanics with the requirements of relativity.
Fr.: fonction de Dirac
A function of x defined as being zero for all values of x other than x = x0 and having the definite integral from x = -∞ to x = +∞ equal to unity.
Fr.: constante de Dirac
1) râst (#), sarrâst (#); 2) râštidan
Fr.: 1) direct; 2) diriger
1a) Proceeding in a straight course or line without deviation or interruption.
From L. directus "straight," p.p. of dirigere "set straight," from → dis- "apart" + regere "to guide;" cognate with Pers. râst, as explained below.
Râst "right, straight" (râšt in afrâštan); Mid.Pers.
râst; O.Pers. rāsta- "straight, true," rās-
"to be right, straight, true," rād- "to prepare;" Av. rāz-
"to direct, put in line, set," razišta- "straightest, most correct,"
erezu- "correct, straight," rāzayeiti "directs," razan- "order;"
Skt. raj- "to direct, stretch," rjuyant- "walking straight;"
Gk. orektos "stretched out;" L. regere "to lead straight, guide, rule,"
p.p. rectus "right, straight;" Ger. recht; E. right;
PIE base *reg- "right, just; to move in a straight line."
Fr.: corrélation directe
A correlation between two variables such that as one variable becomes large, the other also becomes large, and vice versa. The correlation coefficient is between 0 and +1. Also called positive correlation.
direct current (DC)
Fr.: courant continu
An → electric current which flows in one direction only and which is substantially constant in magnitude. Virtually all electronic and computer hardware needs direct current to function. → Alternating current can be converted to direct current by means of a power supply consisting of a → transformer.
jonb eš-e farârow, ~ sarrâst
Fr.: mouvement direct
The motion of a solar system body from West to East across the sky against the background stars. It is the "normal" direction of motion within the solar system. For rotating or orbiting solar system objects it is anti-clockwise as seen from above the solar system in the direction of the North Pole. The same as → prograde motion. See also → retrograde motion.
Fr.: objet direct
A word or group of words representing the person or thing upon which the action of a verb is performed or toward which it is directed. In English, generally coming after the verb, without a preposition. In He saw it the pronoun it is the direct object of saw (Dictionary.com).
Fr.: graphe orienté
In → graph theory, an edge where endpoints are distinguished; one is the head and the other is the tail. A directed edge is specified as an ordered pair of → vertices, u, v and is denoted by (u, v) or u→ v.
Fr.: graphe orienté
Fr.: chemin orienté
1) râstâ, su (#); 2) râštâri
1) A position to which motion or another position is referred.
M.E. direccioun, from M.Fr., from L. direction-, stem of directio "arranging in line, straightening," → direct.
Fr.: angle de direction
An angle made by a given vector and a coordinate axis.
A person who directs a project, a group, a production.
From → direct + -tor a suffix found in loanwords from L., forming personal agent nouns from verbs.
Râštâr, from râšt- stem of râštidan→ direct + -âr suffix of agent noun (as in parastâr "nurse").
Fr.: condition de Dirichlet
One of the following conditions for a → Fourier series
A substance, such as mud or dust, that soils someone or something (OxfordDictionaries.com)
Metathesis of M.E. drit, drytt "mud, dirt, dung," from O.N. drit, cognate with O.E. dritan.
Cerk "dirt, filth."
→ dirt + suffix -y.
Fr.: glace sale
Interstellar ice grains with graphite, silicates, or other chemical compounds adsorbed on their surfaces.
dirty iceball model
model-e golule-ye yax
Fr.: modèle de la boule de glace sale
A model for a → cometary nucleus proposed by Fred Whipple (1950-51), according to which the nucleus is a solid body (a few kilometers across) made up of various → ices (→ frozen water, → methane, → ammonia, → carbon dioxide, and → hydrogen cyanide) in which → dust is embedded. Dust particles are liberated when the ices vaporize as the → comet approaches the → Sun, and they get blown away by → solar radiation pressure, often forming impressive, gently curved → dust tails.