triatomic hydrogen molecular ion
yon-e molekuli-ye se-atomi-ye hidrožen
Fr.: ion moléculaire d'hydrogène triatomique, H3+
The hydrogen molecule composed of three atoms in which one of the atoms is ionized. The molecular ion H3+ plays a key role in the chemistry of gaseous → interstellar medium. It reacts efficiently with almost any neutral atom or molecule to initiate a network of ion-neutral reactions. It is responsible for producing molecules such as OH, CO, and H2O. The first detection of H3+ in the interstellar medium, via two closely spaced absorption lines (doublet) near 3.668 μm, were reported in two dense → molecular cloud cores along the lines of sight to the embedded → young stellar objects W33A and GL2136 (Geballe & Oka 1996). Since then H3+ has been detected in several molecular clouds. It is believed that H3+ forms via → cosmic ray → ionization of H2 producing H2+, which quickly reacts to another H2 molecule to form H3+ ( H2 + CR → H2+ and H2+ + H2→ H3+ + H + 1.7 eV).
The property of some crystals of exhibiting three different colors when viewed from three different directions under white lights. → dichroism.
From Gk. tri- "three" + chroic, from chroma "color" + -ism.
Sefâmi, from se, → three, + fâm "color," + -i noun suffix.
Fr.: nébuleuse Trifide
A large luminous → H II region in the constellation → Sagittarius. Also known as M20, NGC 6514. Conspicuous → dust lanes radiating from the center appear to divide the nebula in three → lobes. It is a combined → emission nebula and → reflection nebula, extending for nearly 30' on the sky. Its estimated distance is 4100±200 → light-years (Kuhn et al., 2018, arXiv:1807.02115).
Miq, → nebula; sepâré "split in three," from sé, → three, + pâré "piece, part, portion, fragment;" Mid.Pers. pârag "piece, part, portion; gift, offering, bribe;" Av. pāra- "debt," from par- "to remunerate, equalize; to condemn;" PIE *per- "to sell, hand over, distribute; to assigne;" cf. L. pars "part, piece, side, share," portio "share, portion;" Gk. peprotai "it has been granted;" Skt. purti- "reward;" Hitt. pars-, parsiya- "to break, crumble."
1) mâšé; 2) mâšidan
Fr.: 1) déclancheur; 2) déclancher
1a) (n.) Anything, as an act or event, that serves as a stimulus and initiates or precipitates
a reaction or series of reactions.
Earlier tricker, from Du. trekker "trigger," from trekken "to pull," from M.Du. trecken (cf. M.L.G. trecken, O.H.G. trechan "to draw").
1) Mâšé "a trigger, tongs, pincers," of unknown origin.
Fr.: circuit déclancheur
A circuit in which a specific predetermined action is initiated by an input pulse.
triggered star formation
diseš-e mâše-yi-ye setâré
Fr.: formation d'étoiles déclanchée
Fr.: trigonométrique, circulaire
Fr.: fonction circulaire, ~ trigonomtérique
A function of an angle, one of six functions (sine, cosine, tangent, cotangent, secant, and cosecant) that represent ratios of sides of right triangles. Also called circular function.
didgašt-e sebarsanji, ~ sebarsanjik
Fr.: parallaxe trigonométrique
The branch of mathematics dealing with the relations of the sides and angles of triangles; also the various algebraic functions of these relations.
A geometrical method in land surveying for the determination of the relative position of points. In contrast to → triangulation, trilateration involves measuring the lengths of the three sides of touching or overlapping triangles and not their angles.
In composition, having three nitro groups (NO2), especially replacing hydrogen. → trinitrotoluene.
From L. tri-, a combining form meaning → three + nitro- a combining form used in the names of chemical compounds in which the nitro group is present.
Fr.: trinitrotoluène (TNT)
A yellow, solid chemical compound, that does not occur naturally in the environment. More specifically, 2,4,6-trinitrotoluene (C6H2(NO2)3CH3), is commonly known as TNT. It is an explosive extensively used in munitions and for demolitions.
Fr.: 1) trinôme; 2) trinomial
1) A → polynomial that consists of three terms.
A compound → vowel sound resulting from the succession of three simple vowels pronounced in a single syllable (as in power, hour, fire).
M.E., from M.L. triplare "to triple," from L. triplus "threefold, triple," from tri-, → three, + -plus "-fold."
Setâyi, from setâ, from sé→ three + tâ "fold, plait, ply; piece, part," Mid.Pers. tâg "piece, part."
triple alpha process
farâravand-e âlfâ-ye setâyi
Fr.: réaction triple alpha
A chain of nuclear fusion reactions by which three helium nuclei (→ alpha particles) are transformed into → carbon. First two nuclei of helium collide, fuse, and form a nucleus of → beryllium: 4He + 4He ↔ 8Be, which is unstable and will decay back into two helium nuclei within a few 10-17 seconds. However, due to sufficiently high density and temperature in the stellar core, during a third collision between beryllium and helium, carbon is formed: 8Be + 4He → 12C + γ. The triple-alpha process is possible owing to the existence of the → Hoyle state. It is the main source of energy production in → red giants and → red supergiants in which the core temperature has reached at least 100 million K. Also called → Salpeter process.
Fr.: conjonction triple
A rare event involving a particularly intricate set of movements of two planets or a planet and a star where they meet each other three times in a short period either in opposition or at the time of inferior conjunction, if an inferior planet is involved. The visible movement of the planet or the planets in the sky is therefore normally prograde at the first conjunction, retrograde at the second conjunction and again prograde at the third conjunction.
noqte-ye segâné (#)
Fr.: point triple
The definite pressure and temperature at which all three phases of a substance coexist in → phase equilibrium. The triple point of water has a pressure of 4.58 mm of Hg and a temperature of 273.16 °K.
Fr.: étoile triple
A group of three stars visually or physically associated with each other. → triple system.