An Etymological Dictionary of Astronomy and Astrophysics
English-French-Persian

فرهنگ ریشه شناختی اخترشناسی-اخترفیزیک

M. Heydari-Malayeri    -    Paris Observatory

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Number of Results: 30 Search : frequency
natural frequency
  بسامد ِ زاستاری   
basâmad-e zâstâri

Fr.: fréquence naturelle   

Any frequency of small-amplitude oscillation for a system with a position of stable equilibrium and in the absence of external forces. In other words, the frequency of → free oscillation. Also called characteristic frequency.

natural; → frequency.

Nyquist frequency
  بسامد ِ نیکویءیست   
basâmad-e Nyquist

Fr.: fréquence de Nyquist   

The highest frequency that can be determined in a Fourier analysis of a discrete sampling of data.

Nyquist formula; → frequency.

plasma frequency
  بسامد ِ پلاسما   
basâmad-e plâsmâ

Fr.: fréquence de plasma   

The natural frequency at which internal oscillations of a plasma occur. The plasma frequency is proportional to the square root of the electron density. → plasma oscillation.

plasma; → frequency.

quench frequency
  بسامد ِ اسرش   
basâmad-e osereš

Fr.: fréquence de découpage   

The frequency at which an oscillation is intermittently quenched, as in a super-regenerative receiver.

quench; → frequency.

radio frequency
  بسامد ِ رادیویی   
basâmad-e râdio-yi (#)

Fr.: fréquence radio   

The → electromagnetic radiation with the frequency range between 3 → kiloherz (kHz) to 300 → gigahertz (GHz). See also → radio wave.

radio; → frequency.

relative frequency
  بسامد ِ بازانی   
basâmad-e bâzâni

Fr.: fréquence relative   

Statistics: The number of the occurrences of an event divided by the number of observations.

relative; → frequency.

resonance frequency
  بسامد ِ باز‌آوایی   
basâmad-e bâzâvâyi

Fr.: fréquence de résonance   

The frequency at which a system is in → resonance.

resonance; → frequency.

rotation frequency
  بسامد ِ چرخش   
basâmad-e carxeš

Fr.: fréquence de rotation   

1) The number of rotations per unit time of a rotating object.
2) The number of → stellar rotations per unit time. The reciprocal of the → rotation period. This parameter usually refers to the equator of the star, because stars do not rotate as solid bodies.

rotation; → frequency.

synchrotron frequency
  بسامد ِ سینکروترون   
basâmad-e sinkrvtrvn

Fr.: fréquence synchrotron   

The revolution frequency of a → relativistic particle of charge q and mass m in the → uniform magnetic field B of a synchrotron. It is expressed by: fsyn = qB/2πγm, where γ is the → Lorentz factor. This frequency is lower than → cyclotron frequency for a → non-relativistic case.

synchrotron; → frequency.

vibrational frequency
  بسامد ِ شیوشی   
basâmad-e šiveši (#)

Fr.: fréquence de vibration, ~ vibrationnelle   

The frequency at which the atoms in a molecule vibrate. The frequencies of → molecular vibrations in diatomic molecules are in the order of 10-12 to 10-14 Hz. In such molecules, the only → vibrational mode available is along the bond. More complicated molecules have many types of vibration and stretching modes.

vibrational; → frequency.

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