Fr.: principe d'incertitude
A quantum mechanical principle due to Werner Heisenberg which states that the position and momentum of a particle cannot be determined simultaneously with any arbitrary accuracy. These quantities can be determined only with accuracies limited by the relation Δx.Δp ≥ (1/2)ħ, where Δx is the error in the determination of the position and Δp is the error in the momentum. A similar relation holds for the energy of a particle and the time, ΔE.Δt ≥ (1/2)ħ. Same as → Heisenberg uncertainty principle.
unclassified B[e] star (unclB[e])
setâre-ye B[e]-ye bi radé
Fr.: étoile B[e] non-classée
A temporary designation for a → B[e] star that cannot be placed in any of the four known classes.
Fr.: non clair
Difficult to see, hear, understand, or to be sure about.
Not limited by conditions; absolute.
Fr.: non conscient
Not awake and aware; not responding to one's environment.
Fr.: non conscience
A dune on a planetary surface, used in plural form undae.
From L. unda "wave," cognate with → water.
Šen-tal, from šen "sand" + tal "hill, heap."
Fr.: sous-, faible
A prefixal use of under, as to indicate place or situation below or beneath. Contrary to → over-.
M.E., from O.E. (cf. O.H.G. untar, Ger. unter, Goth. undar), from PIE *ndhero- "lower;" cf. Av. aδara- (adj.), aδairi- (prep.) "below;" Mid.Pers. êr "below, down; low, under," adar "low," azêr "below, under" (Mod.Pers. zir "below, down"); Skt. ádhara- "lower;" O.E. under "under, among").
Kam- "little, few; deficient, wanting; scarce" (Mid.Pers. kam "little, small, few," O.Pers./Av. kamna- "small, few").
The abundance of a chemical element being lower than a reference value, in particular compared to that of the Sun.
Fr.: amortissement faible
The behavior of a damped system when the amount of damping is weak so that the system oscillates with the amplitude gradually decreasing to zero. → overdamping.
1) kam-baravardan; 2) kam-baravard
Fr.: 1) sous-estimer; 2) sous-estimation
1) To estimate at too low a value, rate, or the like.
The circumstance in which there are not enough pixels in a star's image. The number of pixels that make up a star's image is determined by the relationship between the telescope focal length, the physical size of the pixels, and the size of the star's image. With an undersampled image it is not possible to obtain accurate estimates of the star's image size or its position. Undersampling occurs when the atmospheric seeing conditions are exceptionally good and the pixel size not small enough.
To perceive the meaning of.
M.E. understanden, understonden, O.E. understandan "comprehend, grasp the idea of," probably literally "to stand in the midst of," from → under- + standan "to stand," cognate with Pers. istâdan, → standard.
Fahmidan, from Ar. fahm + infinitive suffix -idan.
Fr.: compréhension, entendement, intelligence
Fr.: météorite indifférenciée
A type of meteorite in which the constituting materials (stone, glass, metal) are mixed together in a disorderly mass, in contrast to → differentiated meteorites.
→ un-; → differentiated meteorite.
A wave; the motion of waves.
From L.L. undulatus "wavy, undulated," from undula "wavelet," diminutive of L. unda "wave."
Mowješ, verbal noun of mowjidan "to undulate," from mowj→ wave.
From uni- a combining form meaning "one," from L. uni-, from unus, → one;
Yek-, from yek, → one.
Fr.: cristal uniaxe
Crystal with double refraction possessing only one → optic axis.
Fr.: non identifié
unidentified flying object (UFO)
barâxt-e parande-ye nâ-idânidé, padide-ye havâ-fazâyi-ye nâ-idânidé
Fr.: Objet Volant Non Identifié (OVNI)
Any flying object or phenomenon that cannot be identified by the observer.