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particle 1) , 2) zarré (#), 1), 2), 3) pârul Fr.: particule 1) A unit of → matter smaller than the
→ atom or its main components.
The term particle also includes any (currently hypothetical) new particles
that might be discovered, such as the supersymmetric partners of the
→ quarks and → leptons
and → bosons. From L. particula "little bit or part," diminutive of pars (genitive partis), from PIE base *per- "to assign, allot;" cf. Mid.Pers. pârag "gift, offering, bribe;" Mod.Pers. pâreh "gift" (→ partial); Gk. porein "to provide, give, grant," peprotai "it has been granted;" Skt. purtá- "gift, pay, reward." Zarré, from Ar. dharrat "particle." Pârul, from pâr, → part, + -ul, → -ule. |
particle horizon ofoq-e zarré Fr.: horizon des particules For an observer at a given epoch t_{0}, the boundary between the observable and the unobservable regions of the → Universe. Therefore, the distance to the particle horizon at t_{0} defines the size of the → observable Universe. Same as → cosmic horizon. |
particle nature zâstâr-e zarre-yi Fr.: nature de particule A general term to describe → light involving the following phenomena: → reflection, → refraction, and → photoelectric effect. Compare → wave nature. |
particle physics fizik-e zarreyi (#) Fr.: physique des particules The branch of physics that deals with the smallest known structures of matter and energy in order to understand the fundamental particles and forces of nature. |
particular 1) pâruli; 2) pârulé Fr.: particulier 1) (adj.) Of or pertaining to a single or specific person, thing, group, class, occasion, etc.,
rather than to others or all; special rather than → general. M.E., from O.Fr. particuler and directly from L.L. particularis "of a part, concerning a small part," from L. particula, → particle, + -ar, → -al. Pâruli, adj. from pârul, → particle; pârulé, from pârul + nuance adj. -é. |
particular astrolabe ostorlâb-e pâruli Fr.: astrolabe particulier An → astrolabe that serves only a limited number of → latitudes. → particular; → astrolabe. |
particular solution hall-e pâruli Fr.: solution particulière Of partial differential equations, the solution which can be obtained from the general solution by particular choice of the arbitrary functions. → general solution; → singular solution. → particular; → solution. |
particulate pâruldâr, pârulmand Fr.: particule en suspension 1) Of or relating to minute separate → particles. From Mod. L. particulatus, from particula, → particle. From pârul, → particle, + suffix -é or -mand. |
particulate matter (PM) mâdde-ye pâruli Fr.: particule en suspension Meteorology: A complex → mixture of → microscopic → particles and → liquid droplets suspended in the → atmosphere, especially pollutants. → particulate; → matter. |
partition function karyâ-ye pâreš Fr.: fonction de partition In statistical mechanics, the function giving the probability that a particle belong to a population with a specified energy. It is the integral, over the phase space of a system, of the exponential of (-E/kT), where E is the energy of the system, k is Boltzmann's constant, and T is the temperature. M.E., from from O.Fr., from L. partitionem (nominative partitio) "division, portion," from partitus, p.p. of partire "to part;" → function. Karyâ, → function; pâreš, verbal noun from *pâridan, from pâr, pâré "piece, part, portion," parré "portion, segment (of an orange)," pargâlé, "piece, portion; patch;" (dialects Kermâni pariké "portion, half;" Tabari perik "minute quantity, particle;" Lârestâni pakva "patch;" Borujerdi parru "patch"); 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;" Gk. peprotai "it has been granted;" L. pars, as above; Skt. purti- "reward;" Hitt. pars-, parsiya- "to break, crumble." |
parton pârton (#) Fr.: parton In particle physics, a constituent of the hadron originally postulated in the theoretical analysis of high-energy scattering of particles off hadrons. In modern usage, the term parton is often used to mean a quark or a gluon. Coined by the American physicist Richard Feynman (1918-1988), from part, from → particle + → -ion |
parts per million (ppm) pâr dar milion Fr.: partie par million A fraction of a whole number in units of 1/1000,000. It is usually used to describe chemical concentrations, very small amounts of pollutants in air, water, body fluids, and uncertainty. For example 30 ppm is 3 x 10^{-5} or 0.003%. |
pascal (Pa) pâskâl (#) Fr.: pascal The → SI unit of → pressure, that of one → newton per → square → meter. Since 1 Pa is a small pressure, hPa (→ hectopascals) are more widely used. 1 Pa = 10 dyn cm^{-2}, = 1.02 x 10^{-5} kgf cm^{-2} = 10^{-5} bars = 9.87 x 10^{-6} atm = 7.50 x 10^{-3} torr (mm Hg). In honor of Blaise Pascal (1623-1662), French mathematician, physicist, and religious philosopher for his contribution in the study of hydrodynamics and hydrostatics, in particular establishing the principle of the barometer. |
Pascal's barrel experiment âzmâyeš-e celik-e Pascal Fr.: expérience du tonneau de Pascal An experiment carried out by Blaise Pascal in 1646 to demonstrate the hydraulic pressure. A long and narrow vertical pipe was connected to the content of a closed wooden barrel already full of water. He poured a small quantity of water into the pipe, whereby the height of the fluid within the pipe sharply increased. Due to the increase in hydrostatic pressure and → Pascal's law, the barrel could leak and even burst. → pascal (Pa); M.E. barel, from M.Fr. baril, O.Fr. barril; → experiment |
Pascal's law qânun-e pâskâl (#) Fr.: loi de Pascal A change in the pressure of an enclosed incompressible fluid is conveyed undiminished to every part of the fluid and to the surfaces of its container. Named after Blaise Pascal (1623-1662), French mathematician, physicist, and religious philosopher for his contribution in the study of hydrodynamics and hydrostatics, in particular establishing the principle of the barometer. |
Pascal's triangle sebar-e Pascal Fr.: triangle de Pascal An array of numbers in the shape of a triangle, having a 1 at the top and also at the ends of each row. Each number is obtained by summing the two adjacent numbers to it in the preceding row. Each row is a set of → binomial coefficients. In the expansion of (x + y)^{n}, the coefficients of x and y are given by the n-th row of Pascal's traingle. |
Paschen series seri-ye Paschen (#) Fr.: série de Paschen The spectral series associated with the third energy level of the hydrogen atom. The series lies in the infrared, with Pα at 18,751 Å, and Paschen limit at 8204 Å. In honor of Friedrich Paschen (1865-1947), German physicist; → series. |
Paschen-Back effect oskar-e Paschen-Back Fr.: effet Paschen-Back An effect on spectral lines obtained when the light source is located in a strong magnetic field. The strong field disrupts the coupling between the orbital and spin angular momenta, resulting in a different pattern of splitting. Named for the German physicists Friedrich Paschen (1865-1947) and Ernst E. A. Back (1881-1959); → effect. |
Pasiphae Pâsifâé Fr.: Pasiphaé The fifteenth of Jupiter's known satellites, orbiting at 23,660,000 km from Jupiter; also known as Jupiter VIII. Its diameter is 36 km and orbital period 744 days. In Gk. mythology, Pasiphae was the wife of Minos and mother, by a white bull, of the Minotaur. |
passage gozar (#) Fr.: passage An act or instance of passing from one place, condition, etc., to another; transit. Same as → transit. M.E, from O.Fr. passage, from passer "to go by;" originally "a road, passage." Gozar "passage, transit, passing," from gozaštan "to pass, cross, transit," variant gozâštan "to put, to place, let, allow;" Mid.Pers. widardan, widâštan "to pass, to let pass (by);" O.Pers. vitar- "to pass across," viyatarayam "I put across;" Av. vi-tar- "to pass across," from vi- "apart, away from" (O.Pers. viy- "apart, away;" Av. vi- "apart, away;" cf. Skt. vi- "apart, asunder, away, out;" L. vitare "to avoid, turn aside") + O.Pers./Av. tar- "to cross over;" → trans-. |
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