absorption curve xam-e daršam Fr.: courbe d'absorption A graphic representation of the amount of radiant energy absorbed by a material as a function of the wavelength. → absorption; → curve. |
analytic curve xam-e ânâlasi Fr.: courbe analytique A curve whose parametric equations are real → analytic functions of a single real variable. |
blackbody curve xam-e siyah-jesm Fr.: courbe de corps noir The characteristic way in which the → intensity of → radiation emitted by a → blackbody varies with its → frequency (or → wavelength), as described by → Planck's radiation law. Also referred to as the → Planck curve. The exact form of the curve depends only on the object's → temperature. The wavelength at which the emitted intensity is highest is an indication of the temperature of the radiating object. As the temperature of the blackbody increases, the peak wavelength decreases (→ Wien's displacement law) and the total energy being radiated (the area under the curve) increases rapidly (→ Stefan-Boltzmann law). |
calibration curve xam-e kabizeš Fr.: courbe d'étalonnage An empirical curve obtained through appropriate exposures in order to determine the instrument's response. For example, a curve allowing the conversion of relative intensities of an observed object into absolute fluxes, or a curve relating the detector's pixel positions to wavelengths. → calibration; → curve. |
caustic curve xam-e sucân Fr.: courbe caustique The intersection of a → caustic surface with a plane passing through the beam of rays. |
characteristic curve xam-e sereštâri Fr.: courbe caractéristique Graph representing an optical film's response to the amount of light falling on it. → characteristic; → curve. |
closed curve xam-e basté (#) Fr.: courbe fermée A curve whose ends are joined. |
compound curve xam-e candsâxt Fr.: courbe composée A curve that is made up of a series of successive tangent circular arcs. |
Crussard curve xam-e Crussard Fr.: courbe de Crussard A curve, on the pressure versus specific volume plane, representing the locus of all the theoretically possible states that can be attained by the → detonation products of an → explosive. The Crussard curve relates to the → Hugoniot curve through a translation caused by the chemical energy liberated during the detonation. The Crussard curve consists of several portions characterizing various burning regimes: detonations (strong and weak), a forbidden region, and → deflagrations (weak and strong). Named after the French engineer Jules Louis Crussard (1876-1959), who conducted several pioneering studies in mining techniques, in particular on shock waves (Ondes de choc et onde explosive, Bulletin de la Société de l'industrie minérale de Saint-Etienne, 4e série, tome VI, 1907); → curve. |
curve xam (#) Fr.: courbe A line that deviates from straightness in a smooth, continuous fashion. A line representing a variable on a graph. From L. curvus "crooked, curved, bent;" cf. Av. skarəna- "round," Gk. kirkos, krikos "a ring;" PIE base *sker- "to turn, bend." Xam, variant kamân "arc," Mid.Pers. kamân, probably from PIE *kamb- "to bend, crook," cf. Breton kamm "curved, bent." |
curve fitting saz-e xam, sazkard-e ~ Fr.: ajustement de courbe Construction of mathematical functions whose graphs are curves that "best" approximate a given collection of data points. |
curve of growth xam-e ruyeš Fr.: courbe de croissance A plot showing how the → equivalent width of an → absorption line, or the radiance of an → emission line, increases as a → function of the → number of → atoms that produce the line. |
curved xamidé (#) Fr.: courbé Not straight. Adj. from → curve. |
dispersion curve xam-e pâšeš Fr.: courbe de dispersion A graph displaying the variation of the → refractive index of a substance against the wavelength of the electromagnetic wave passing through the substance. → dispersion; → curve. |
drift curve xam-e delek Fr.: courbe de passage In radio astronomy, the output response as a function of position for a given filter as the source passes through the beam. |
exponential curve xam-e nemâyi (#) Fr.: courbe exponentielle A curve that represents an → exponential function. → exponential; → curve. |
extinction curve xam-e xâmuši Fr.: courbe de l'extinction interstellaire A graph representing the variation of the → interstellar extinction against → wavelength. Usually it displays the → normalized values of extinction as a function of (the → inverse) of the wavelength (in → microns). See, e.g., Sandage & Mathis, 1979, Ann. Rev. Astron. Astrophys. 17, 73. → extinction; → curve. |
family of curves xânevâde-ye xamhâ Fr.: famille de courbes A set of similar curves which are distinguished by the values taken by one or more parameters in their general equation. For example, the general solution of a differential equation is represented by a family of curves. |
flat rotation curve xam-e carxeš-e taxt Fr.: courbe de rotation plate A galactic → rotation curve in which the → rotation velocity is constant in the outer parts. The flat component is preceded by a rising curve that shows solid body rotation in the very center of the → galaxy. A flat rotation curve implies that the mass is still increasing linearly with radius. See also → dark matter. |
Hugoniot curve xam-e Hugoniot Fr.: courbe de Hugoniot A curve, on the pressure versus specific volume plane, representing the locus of all the possible states that can be reached by a substance immediately after the passage of a single → shock wave. For each initial condition there is a different curve. No combustion occurs in the process and, therefore, the chemical composition of the medium does not change. See also → Rayleigh line; → Crussard curve. Named after the French physicist Pierre Henri Hugoniot (1851-1887), who worked on fluid mechanics, especially flow properties before and after shock waves; → curve. |