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alkaline earth metal
felez-e qalyâyi-ye xâki (#)
Fr.: terre alcaline
Any of the metallic chemical elements belonging to group 2 of the → periodic table; i.e. → beryllium, → magnesium, → calcium, → strontium, → barium, and → radium. They are not found free in the nature because they are highly reactive.
Felez, → metal; qalyâyi, → alkaline; xâki "of or pertaining to soil," from xâk, → soil.
Fr.: particule alpha
A positively charged particle emitted from the nuclei of certain atoms during radioactive disintegration. The alpha particle has an atomic weight of 4 and a positive charge equal in magnitude to 2 electronic charges; hence it is essentially a helium nucleus.
Any → elementary particle with a → charge of opposite sign to the same particle in normal matter.
The process or product of human activity which is the expression of creativity and/or imagination that appeals to the senses or emotions.
From O.Fr. art, from L. artem, (nominative ars) "art, skill, craft;" from PIE base *ar- "to fit, join;" cf. Mod.Pers. arm "arm, from the elbow to the shoulder;" Av. arma-, arəmo- "arm;" Skt. irma- "arm;" Gk. arthron "a joint;" L. armus "shoulder."
Honar, from Mid.Pers. hunar "skill, ability, virtue, manliness;" O.Pers. hūnarā- "abilities, skills;" Av. hunara- "ability, skill"; cf. Skt. sūnára- "powerful, joyous, beautiful;" Proto-Iranian *Hnar- "to be able, strong."
A blood vessel that conveys blood from the heart to any part of the body (Dictionary.com).
M.E. arterie, O.Fr. artaire, from L. arteria, from Gk. arteria "windpipe," also "an artery," as distinct from a vein; related to aeirein "to raise."
Sorxrag, literally "red vessel," from sorx, → red, + rag, → vessel.
1) A nonfictional prose composition usually forming an independent
part of a publication in a magazine.
Article, from O.Fr. article, from L. articulus, diminutive of artus "a joint".
Vetâr, from Kurd. witâr "article, speech," from witten "to speak, say," from wit-; cf. Pers. vât "letter, word," vâžé "word;" Av. vac- "to speak, say;" Proto-Iranian *uac- "to say, speak;" → letter.
Fr.: objet fabriqué, artefact
1) An object made by a human being, typically one of cultural or historical
From It. artefatto, from L. arte "by skill" (ablative of ars "→ art") + factum "thing made," from facere "to make, do," → -fy.
Dasâc "hand made," from das variant of dast, → hand, + sâc, variant of sâz-, sâxtan, → agree.
Not occurring naturally; produced by man.
M.E., from O.Fr., from L. artificialis "belonging to art," from artificium "craftsmanship."
Sâxtegi "artificial," from sâxtan "to build, to make," → structure.
Fr.: horizon artificiel
A shallow flat vessel filled with → mercury or some other viscous → liquid used in special → sextant for measuring altitudes of celestial bodies at sea in the absence of a → visible horizon.
→ artificial; → horizon.
Fr.: langue artificielle
An artificially created language system for international communication or for a specific intellectual or scientific purpose. Examples include Esperanto, computer programing languages, → symbolic logic, and → tensor analysis.
→ artificial; → language.
Fr.: lumière artificielle
Any light other than that which proceeds from the heavenly bodies.
→ artificial; → light.
Fr.: satellite artificiel
A man-made equipment that orbits around Earth or a solar system body.
→ artificial; → satellite.
Fr.: étoile artificielle
In → adaptive optics, a point source created on the sky by means of a laser beam in order to correct for the → atmospheric turbulence. A laser tuned to the wavelength of 589 nm will excite sodium atoms at an altitude of ~ 100 km in the Earth's atmosphere, producing an artificial "star."
→ artificial; → star.
Fr.: physique des astroparicules
The area of science which deals with → elementary particle and → high-energy phenomena in → astrophysics and → cosmology.
beam of particles
Fr.: faisceau de particules
A narrow unidirectional flow of particles
zarre-ye betâ (#)
Fr.: particule bêta
An → electron or a → positron emitted from an unstable nucleus during a → radioactive process known as → beta decay.
The term "beta particle" relates to the early history of the → radioactivity studies when the nature of the emergent particles was not elucidated; → particle.
qânun-e Biot-Savart (#)
Fr.: loi de Biot-Savart
The → magnetic field due to → electric current flowing in a long straight conductor is directly proportional to the current and inversely proportional to the distance of the point of observation from the conductor. The law is derivable from → Ampere's law, but was obtained experimentally by the authors.
Named after the French physicists Jean-Baptiste Biot (1774-1862) and Félix Savart (1791-1841); → law.
Of or relating to René → Descartes, his mathematical system, or his philosophy, especially with regard to its emphasis on logical analysis and its mechanistic interpretation of physical nature. → Cartesian coordinates; → Cartesian vortex theory.
From L. Cartesianus, from Cartesius, Latinized form of the name of French philosopher and mathematician René Descartes (1596-1650), + suffix -ian.
Fr.: coordonnées cartésiennes
A → coordinate system in which the position of a point is specified by two (in a plane) or three (in 3-dimensional space) → real numbers representing the distances from two perpendicular axes or from three perpendicular planes, respectively. René Descartes (1596-1650) introduced the coordinates system in his La Géométrie in 1637.
→ Cartesian; → coordinate.
Cartesian vortex theory
negare-ye gerdšâr-e Descartes
Fr.: théorie des vortex de Descartes
A mechanical model put forward before Newton's theory of gravity to explain the revolution of the planets around the Sun. Descartes in his 1644 Principia Philosophiae postulated that the space between the Sun and the planets is filled with matter in the form of a fluid. The fluid rotates in countless whirlpools, one for each planet, thus carrying the planets along in their flow. The vortices vary in size and are contiguous as well as nested. Descartes believed that two objects can exert force on each other only when they are in physical contact. This is why he postulated that space is filled with matter. Newton refuted the vortex theory, using the principle of → action at a distance on which relies his → law of universal gravitation.
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