Fr.: équinoxe moyen
A fictitious equinox whose position is that of the vernal equinox at a particular epoch with the effect of nutation removed.
mean free path
puyeš-e âzâd-e miyângin (#)
Fr.: libre parcours moyen
The mean distance which a particle moves between two successive collisions with other particles of the medium. Mean free path is inversely proportional to the number of particles per cm3 (n), and the collision → cross section (σ). In the case of a gas with molecules having a diameter of d, the cross section is equal to the area of a circle of radius d, i.e. σ = πd2, and the mean free path is given by: l = 1/(nσ). Taking into account the relative velocity distribution of the colliding molecules, l = 1/(√2 . nσ). For a gas at one atmosphere pressure and room temperature, the average distance between molecules is roughly 3.5 × 10-7 cm, that is some 35 times the diameter of a molecule. Taking the gas density n = 2.4 × 1014 molecules cm-3, and a typical diameter d = 2 × 10-8 cm for a molecule, the mean free path is 3.3 × 10-5 cm. This means that the average distance between collisions is about 95 times the average distance between molecules.
Fr.: vie moyenne
The average amount of time an unstable radioisotope exists before it decays, It is equal to 1.44 times the half-life.
mean molecular weight
vazn-e molekuli-ye miyângin (#)
Fr.: poids moléculaire moyen
The total atomic or molecular weight divided by the total number of particles. For instance, the mean molecular weight of a plasma of pure ionized 4He would be 4 (the atomic mass number) divided by 3, the total number of particles (1 nucleus plus 2 electrons), i.e. 4/3.
mâh-e miyângin (#)
Fr.: lune moyenne
A fictitious Moon that has the same average motion as the true Moon but that is not subject to any gravitational perturbations by other bodies.
jonbeš-e miyângin (#)
Fr.: mouvement moyen
The average angular velocity of a satellite in an elliptical orbit.
Fr.: parallaxe moyenne
The parallax, derived by means of statistical studies of brightness and motions, for a large group of stars whose individual parallaxes cannot be measured.
Fr.: position moyenne
An object's celestial position as determined for a given mean equator and equinox. → mean position.
Fr.: pôle moyen
The direction of the Earth's axis at a particular epoch if the nutation is ignored.
Fr.: position moyenne
Same as → mean place.
Fr.: profil moyen
The shape of a pulsar's pulse as determined by averaging several pulses.
mean sidereal day
ruz-e axtari-ye miyângin
Fr.: jour sidéral moyen
mean sidereal time
zamân-e axtari-ye miyângin (#)
Fr.: temps sidéral moyen
The hour angle of the mean equinox for a given observer.
mean solar day
ruz-e xoršidi-ye miyângin (#)
Fr.: jour solaire moyen
The average length of the apparent solar day. In other words, the interval between successive transits of the mean Sun for a given observer.
mean solar time
zamân-e xoršidi-ye miyângin (#)
Fr.: temps solaire moyen
The time since the mean Sun crossed the meridian with 12 hours added to make the day begin at midnight.
Fr.: spectre moyen
A plot of the mass-to-charge ratio of elementary particles, sorted by their isotopic mass.
xoršid-e miyângin (#)
Fr.: Soleil moyen
A hypothetical Sun that moves along the ecliptic at a uniform rate equal to the average motion of the real Sun.
Fr.: terme moyen
mean value theorem
farbin-e arzeš-e miyângin
Fr.: théorème des accroissements finis
1) If f(x) is a continuous function on the interval from a to b, then:
Fr.: sens, signification
M.E., from mean; O.E. mænan "to mean, intend, signify" (cf. O.Fris. mena "to signify," O.S. menian "to intend, signify," M.Du. menen, Du. meenen, Ger. meinen "think, suppose"), related to Pers. maneš "disposition, temperament," mênidan "to think, consider," → idea; + → -ing.
Cemâr, from cem or cim "meaning, signification;" Mid.Pers. cim "meaning, reason, cause;" ultimately from Proto-Ir. *cahmāt "wherefore?" cf. Skt. kasmāt "why, where from? whence?," kim "what? how? why?" + âr short form of âvar present stem of âvardan "to cause or produce; to bring," → production, as in bonâr, → cause, used also as a nuance suffix; see also the verb → mean.