zâviye-ye fâz (#)
Fr.: angle de phase
1) Physics: Of a → periodic wave,
the number of suitable units of angular
measure between a point on the wave and a reference point.
Fr.: courbe de phase
1) Astro.: A curve describing the → brightness
of a reflecting → natural satellite as a
function of its → phase angle.
Fr.: délai de phase
The ratio of the phase shift of a sinusoidal signal in transmission through a system to the frequency of the signal.
Fr.: diagramme de phases
A graph showing the equilibrium relationships between phases (such as vapor-liquid, liquid-solid) of a chemical compound, mixture of compounds, or solution.
Fr.: différence de phase
The difference of phase (usually expressed as a time or an angle) between two periodic quantities which vary sinusoidally and have the same frequency.
Fr.: équilibre de phases
The condition of temperature and pressure under which different phases (e.g. gas, liquid, and solid) of a substance coexist.
Fr.: fonction de phase
The variation in brightness of a target as the phase angle (the angle between Sun and observer as seen from the target) varies between 0Â° and 180Â°. The directional distribution of reflected (or scattered) radiation. The phase angle is the supplement of the scattering angle (the angle between the incident ray and the emerging ray); in other words, the sum of the phase angle and the scattering angle is always 180Â° (Ellis et al., 2007, Planetary Ring Systems, Springer).
Fr.: différence de phase
1) General: Same as → phase difference.
→ phase; lag, possibly from a Scandinavian source; cf. Norw. lagga "go slowly."
Fr.: blocage de phase
In electronics, a technique of adjusting the phase of an oscillator signal so that it will follow the phase of a reference signal.
→ phase; lock, from O.E. loc "bolt, fastening, enclosure;" cf. O.N. lok "fastening, lock," Goth. usluks "opening," O.H.G. loh "dungeon," Ger. Loch "opening, hole," Du. luck "shutter, trapdoor."
Fâz, → phase; bast "fastening, lock," from bastan, from Mid.Pers. bastan/vastan "to bind, shut," Av./O.Pers. band- "to bind, fetter," banda- "band, tie," Skt. bandh- "to bind, tie, fasten," PIE *bhendh- "to bind," cf. Ger. binden, E. bind, → band.
degarâhangeš-e fâz (#)
Fr.: modulation de phase
Modulation in which the phase angle of a sine-wave carrier is caused to depart from the carrier angle by an amount proportional to the instantaneous magnitude of the modulating wave.
vâgardâni-ye fâz, vâruneš-e ~
Fr.: inversion de phase
An angular shift in phase by 180Â°.
Fr.: décalage de phase
Any change in the phase of a periodic quantity or in the phase difference between two or more periodic quantities.
Fr.: espace des phases
Of a dynamical system, a six-dimensional space consisting of the set of values that the position and velocity can take together (x, y, z, vx, vy, vz). → velocity space.
phase transfer function (PTF)
karyâ-ye tarâvaž-e fâz
Fr.: fonction de transfert de phase
A measure of the relative phase in the image as function of frequency. It is the phase component of the → optical transfer function. A relative phase change of 180Â°, for example, results in an image with the black and white areas reversed.
Fr.: transition de phase
The changing of a substance from one phase to another, by → freezing, → melting, → boiling, → condensation, or → sublimation. Also known as phase transformation. A well known phase transition is the transition from → water to → ice. Phase transitions are often associated with → symmetry breaking. In water there is a complete symmetry under rotations with no preferred direction. Ice has a crystal structure, in which certain orientations in space are preferred. Therefore, in transition from water to ice the continuous rotational symmetry is lost.
Fr.: vitesse de phase
The speed at which any fixed phase (individual wave) in a → wave packet travels. It is expressed as vph = ω/k, where ω is the → angular frequency and k the → wave number. See also the → group velocity.
phases of the Moon
Fr.: phases de la lune
→ Lunar phase.
phases of Venus
Fr.: phases de VÃ©nus
The gradual variation of the apparent shape of → Venus between a small, full → disk and a larger → crescent. The first telescopic observation of the phases of Venus by Galileo (1610) proved the → Ptolemaic system could not be correct. The reason is that with the → geocentric system the phases of Venus would be impossible. More specifically, in that model Venus lies always between Earth and Sun. Hence its fully bright surface would always be toward the Sun; so Venus could not be seen in full phase from Earth. Only slim crescents would be possible. On the other hand, this phenomenon could not prove the → heliocentric system, because it could equally be explained with the → Tychonic model.
The study of the biological recurring phenomena in plants and animals (such as blossoming, hibernation, reproduction, and migration) and of their relation to changes in season and climate.
From L. phaeno-, from Gk. phaino-, from phainein "bring to light, cause to appear, show," from PIE root *bha- "to shine" + → -logy.
1) An occurrence, circumstance, or fact, in matter or spirit, which can be perceived
by human senses. → physical phenomenon.
From L.L. phÃ¦nomenon, from Gk. phainomenon "that which appears or is seen," from phainesthai "to appear," passive of phainein "to bring to light; to show," from PIE base *bhhā- "to shine;" cf. Skt. bhāati "shines, glitters;" Av. bā- "to shine, appear, seem," bāmya- "light, luminous, bright," bānu- "light, ray;" Mid.Pers. bâm "beam of light, splendor," bâmik "brilliant," bâmdâd "morning, dawn."
Padidé, noun from padid "manifest, evident, conspicuous, in sight," variant padidâr, from Mid.Pers. pad didâr "visible," from pad "to, at, for, in," evolved to bé "to; for; in; on; with; by" in Mod.Pers. (O.Pers. paity; Av. paiti "to, toward, in, at;" cf. Skt. práti, Gk. poti) + did past stem of didan "to see, regard, catch sight of, contemplate, experience" (O.Pers. dī- "to see;" Av. dā(y)- "to see," didāti "sees;" cf. Skt. dhī- "to perceive, think, ponder; thought, reflection, meditation," dādhye; Gk. dedorka "have seen").