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Number of Results: 38 Search : density

charge density cagâli-ye bâr Fr.: densité de charge The → |

column density cagâli-ye sotun Fr.: densité de colonne Density of the interstellar matter lying between an object and the Earth in a cylinder with a unity base. |

critical density cagâli-ye paržani Fr.: densité critique 1) c is the → speed of light,
G is the → gravitational constant, and
H the → _{t}Hubble parameter.
The critical density is currently 9.3 × 10^{-30}g cm^{-3},
about 6 hydrogen atoms per cubic meter
(for H = 70 km s_{0}^{-1} Mpc^{-1}). 2) In → gravitational lensing, the minimum density that
would be needed by an intervening object to bend light rays.
It is expressed by:
Σ = (c^{2}/4πG)(d),
where _{os}/d_{ol}d_{ls}c is the speed of light, G is
the gravitational constant,
d, _{os}d, and _{ol}d
represent angular diameter distances between the observer and the source,
the observer and the lens, and the lens and the source respectively.
It has units of mass per unit solid angle. _{ls}3) Radiative processes: The density at which the collisional
→ de-excitation rate
equals the → radiative transition rate.
The critical density for level j is given by:
n,
where _{c} = Σ_{i < j} A_{ji} = Σ_{i ≠ j} q_{ji}A is the → _{ji}Einstein coefficient of
→ spontaneous emission
and q is the rate for collisional de-excitation
of → _{ji}energy level j, summed over all possible processes.
This expression often simplifies to the ratio
of two numbers, since in many cases there is a single
important path for emission and a dominant collisional de-excitation process.
In the low density limit the → emissivity
is proportional to the product
N (electron density) x _{e}N (ion density),
whereas for densities exceeding the critical density, the emissivity is proportional to
_{i}N. Thus, line emission in a nebula occurs most efficiently near
the critical density._{i} |

current density cagâli-ye jarayân Fr.: densité de courant The electric current per unit of cross-sectional area perpendicular to the direction of
current flow. It is a vector quantity and represented by symbol |

density cagâli (#) Fr.: densité The amount of any quantity per unit volume. The mass density is the
mass per unit volume. The energy density is the energy per unit
volume; particle density is the number of particles per unit volume. Noun form of → |

density fluctuation oftâxizhâ-ye cagâli Fr.: fluctuations de densité In the early Universe, localized enhancements in the density of either matter alone or matter and radiation. According to models, very small initial fluctuations (less than 1 percent) can lead to subsequent formation of galaxies. → |

density parameter pârâmun-e cagâli Fr.: paramètre de densité One of the four terms that describe an arranged version of the
→ dark energy. 4) For the → curvature of space-timeΩ_{k} = -kc^{2}/(R^{2}H^{2}),
where k is the → curvature constant
and R the
→ cosmic scale factor. Note that: Ω _{m} + Ω_{r} + Ω_{Λ} +
Ω_{k} = 1, and
Ω_{total} = Ω_{m} + Ω_{r} +
Ω_{Λ} = 1 - Ω_{k}. |

density profile farâpâl-e cagâli Fr.: profile de densité 1) A → |

density wave mowj-e cagâli (#) Fr.: onde de densité A wave phenomenon in which the density fluctuations of a physical quantity
propagates in a compressible medium. For example,
the → |

density wave theory negare-ye mowj-e cagâli Fr.: théorie des ondes de densité One possible explanation for → |

density-bounded H II region nâhiye-ye H II-ye cagâli karânmand Fr.: bornée par la densité An → |

electron density cagâli-ye elektroni (#) Fr.: densité électronique The number of electrons per unit volume in an ionized medium, like an
→ |

energy density cagâli-ye kâruž Fr.: densité d'énergie The amount of energy in the form of radiation per unit volume, expressed in
ergs cm a = 7.56 × 10^{-15} erg cm^{-3} (K)^{-4}. |

flux density cagâli-ye šârr Fr.: densité de flux Flux of radiation that falls on a detector per unit surface area of the detector per unit bandwidth of the radiation per unit time. |

Lagrangian density cagâli-ye Lagranži Fr.: densité lagrangienne A quantity, denoted Lagrangian formalism, and defined as the
→ Lagrangian per unit volume.
It is related to the Lagrangian L by: L = ∫∫∫L d_{d}^{3}V. Lagrangian density is often called Lagrangian when there is no ambiguity. → |

magnetic flux density cagâli-ye šâr-e meqnâtisi (#) Fr.: densité du flux magnétique A vector quantity measuring the strength and direction of the magnetic field. It is
the → |

mass density cagâli-ye jermi Fr.: densité massique The mass per unit area of the ring material, integrated through the
thickness of the ring. Sometimes called → |

maximum density of water cagâli-ye bišine-ye âb Fr.: densité maximale de l'eau The density of pure water occurring at 3.98 °C, which is 1.0000 g cm |

morphology-density relation bâzâneš-e rixt-cagâli Fr.: relation morphologie-densité An observationally determined
relationship between the → → |

neutral density filter pâlâye-ye cagâli-ye natâr Fr.: filtre neutre A filter having a flat response over the range of wavelengths of interest. Also
called |