# An Etymological Dictionary of Astronomy and AstrophysicsEnglish-French-Persian

## فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

### M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 1965 Search : ion
 categorical proposition   گزاره‌ی ِ کتاگریک   gozâre-ye katâgorikFr.: proposition catégorique   In a → syllogism, a → proposition or statement that deals with inclusion or exclusion of members of → subject classes in → predicate classes. Categorical propositions are of four basic forms, see → Aristotelian form. cation   کاتیون   kâtion (#)Fr.: cation   Chemistry: A → positively charged → ion that is attracted to the → cathode in electrolysis. Any positively charged atom or group of atoms (opposed to → anion).From cat-, → cathod, + → ion. Cauchy's equation   هموگش ِ کوشی   hamugeš-e CauchyFr.: équation de Cauchy   A relationship between the → refractive index (n) and the wavelength of light (λ) passing through a medium. It is commonly stated in the following form: n = A + B/λ2 + C/λ4, where A, B, and C are constants characterizing the medium. The two-component Cauchy equation is n = A + B/λ2, from which the dispersion becomes dn/dλ = -2B/λ3 showing that dispersion varies approximately as the inverse cube of the wavelength. The dispersion at 4000 A will be about 8 times as large as at 8000 Å.Named after Augustin Louis Cauchy (1789-1857), French mathematician and physicist who found the first equation of dispersion in 1836; → equation. causation   بنارش   bonârešFr.: relation de cause à effet   1) The act or process of causing; the act or agency which produces an effect. 2) The relation of → cause to → effect.Verbal noun from → cause. center of attraction   مرکز ِ درکشش   markaz-e darkašešFr.: centre d'attraction   A point toward which a force on a body is always directed.→ center; → attraction. centrifugal acceleration   شتاب ِ مرکزگریز   šetâb-e markaz-goriz (#)Fr.: accélération centrifuge   Of a point rotating in a circle round a central point, the outward acceleration away from the rotation axis. It corresponds to → centrifugal force. The centrifugal acceleration is given by ω x ω x r, or v2/r, where ω is → angular velocity, r the distance to the rotating axis, and v the → tangential velocity. The centrifugal and → centripetal accelerations are equal and opposite. centripetal acceleration   شتاب ِ مرکزگرا   šetâb-e markaz-gerâ (#)Fr.: accélération centripète   The rate of change of the → tangential velocity of a body moving along a circular path. The direction of centripetal acceleration is always inward along the → radius vector of the → circular motion. The magnitude of the centripetal acceleration is related to the → tangential velocity (v) and → angular velocity (ω) as follows: ac = v2/r = rω2. According to → Newton's second law, an object undergoing centripetal acceleration is experiencing a → centripetal force. chain reaction   واژیرش ِ زنجیری، واکنش ِ ~   vâžireš-e zanjiri, vâkoneš-e ~Fr.: réaction en chaîne   A succession of → nuclear fissions when the neutrons released by previous fissions produce other nuclear fissions which themselves cause other reactions and the reactions goes on increasing exponentially.→ chain; → reaction. characteristic equation   هموگش ِ سرشتاری   hamugeš-e sereštâriFr.: équation caractéristique   Physics: An analytical relationship between a set of physical variables that determines the state of a physical system. Math.: The equation which is solved to find a matrix's eigenvalues, also called the characteristic polynomial. characterization   ۱) سرشتارش؛ ۲) تنومسا سازی   1) sereštâreš 2) tanumsâ sâziFr.: 1) caractérisation; 2) représentation des caractères   1) The act of describing the character or qualities of someone or something. 2) The artistic representation (as in fiction or drama) of human character or motives (Merriam-Webster.com).→ characterize; → -tion. charge conjugation   همیوغش ِ بار   hamyuqeš-e bâr (#)Fr.: conjugaison de charges   In particle physics, an operation that changes a particle to its antiparticle in equations describing subatomic particles or, equivalently, reverses its charge and magnetic moment.→ charge; → conjugation. charge distribution   واباژش ِ بار   vâbâžeš-e bârFr.: distribution des charges   The way a number of → electric charges are arranged in space with respect to the point of observation.→ charge; → distribution. charge-injection device (CID)   دستگاه ِ درشانش ِ بار   dastrgâh-e daršâneš-e bârFr.: dispositif à injection de charge   A charge-transfer device that passes along stored charges positioned at predetermined locations; it is used as an image sensor in which the image points are accessed by reference to their horizontal and vertical coordinates.→ charge; → injection; → device. chemical adsorption   برشم ِ شیمیایی   baršam-e šimiyâyiFr.: adsorption chimique   Same as → chemisorption.→ chemical; → adsorption. chemical composition   همنهش ِ شیمیک   hamneheš-e šimikFr.: composition chimique   The identities, and relative abundances of the → chemical elements or → compounds that make up a substance.→ chemical; → composition. chemical equation   هموگش ِ شیمیایی   hamugeš-e šimiyâyiFr.: équation chimique   The symbolic representation of a chemical reaction where the formulae of the → reactants are placed on the left and the formulae of → products on the right of an arrow.→ chemical; → equation. chemical evolution   فرگشت ِ شیمیایی   fargašt-e šimiyâyi (#)Fr.: évolution chimique   A cumulative change in the chemical properties, or more specifically, the relative abundances of chemical elements in an astrophysical system.→ chemical; → evolution. chemical reaction   واژیرش ِ شیمیایی، واکنش ِ ~   vâžireš-e šimiyâyi, vâkoneš-e ~Fr.: réaction chimique   A → change or → transformation in which a → substance → decomposes, → combines with other → substances, or interchanges constituents with other substances.→ chemical; → reaction. chemical separation   جدایی ِ شیمیایی   jodâyi-ye šimiyâyiFr.: séparation chimique   The physical processes that can cause certain elements to migrate in a → stellar atmosphere. These processes are thought to be important in creating the chemical peculiarities seen in → Am stars and → Ap stars.→ chemical; → separation. chemisorption   شیمی‌شمش   šimi-šamešFr.: chimisorption   A kind of → adsorption in which the forces involved are → valence forces of the same kind as those operating in the formation of → chemical compounds. Same as → chemical adsorption. See also → physisorption.Chemi-, from → chemical; → sorption.