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: 5 Search : debye
 debye (D)   دبی   debye (#)Fr.: debye   A → unit of electric → dipole moments, equal to 10-18 → CGS units or 3.336 x 10-30 → coulomb meter.After Peter Joseph Wilhelm Debye (1884-1966), Dutch-born American, who made important studies in the conductivity of electricity by salt solutions and in the heat capacity of solids. He received the 1936 Nobel Prize in chemistry for his work on the structure of molecules. Debye law   قانون ِ دبی   qânun-e Debye (#)Fr.: loi de Debye   The → Debye model at → low  → temperatures, where the → specific heat is proportional to the cube of the → absolute temperature, i.e. CV ∝ T3.→ debye; → law. Debye length   درازای ِ دبی   derâzâ-ye Debye (#)Fr.: longueur de Debye   A characteristic length scale in a → plasma, determined by the temperature and number density of the charged particles. The Debye length (in cm) is given by the expression: λD = 743(Te/ne)1/2, where Te is the electron temperature in → electron-volts and ne is the electron density in cm-3. Particles which pass each other at distances smaller than the Debye length interact directly. Outside the Debye length particle interactions are dominated by collective effects. In typical laboratory plasmas the Debye length is small compared with the plasma dimension, so that collective effects are important.→ debye (D); → length. Debye model   مدل ِ دبی   model-e Debye (#)Fr.: modèle de Debye   An extension of the → Einstein model accounting for → specific heats, based on the concept of → elastic waves in → crystals. In this model specific heat is given by: CV = 9R[(4/x2)∫ y2/(ey - 1)dy - x/(ex - 1)], integrating from 0 to x, where R is the → gas constant, k is → Boltzmann's constant, x = hνmax/k, and y = hν/k. The parameter TD = hνmax/k is the characteristic → Debye temperature of the crystal. At low temperatures the specific heat prediction by this model is in good agreement with observations (→ Debye law), in contrast to Einstein's model.→ debye; → temperature. Debye temperature   دمای ِ دبی   damâ-ye Debye (#)Fr.: température de Debye   The characteristic → temperature of the → crystal as given by the → Debye model of → specific heats.→ debye; → temperature.