You can mark you interesting snippets of text that will be available through a unique link in your browser.


fluorescence

Translation
fluorescence
/floo res"euhns, flaw-, floh-/, n. Physics, Chem.
1. the emission of radiation, esp. of visible light, by a substance during exposure to external radiation, as light or x-rays. Cf. phosphorescence (def. 1).
2. the property possessed by a substance capable of such emission.
3. the radiation so produced.
[1852; FLUOR(SPAR) + -ESCENCE, on the model of OPALESCENCE, in reference to the mineral's newly discovered property]

* * *

Emission of electromagnetic radiation, usually visible light, caused by excitation of atoms in a material, which then reemit almost immediately (within about 10-8 seconds).

The initial excitation is usually caused by absorption of energy from incident radiation or particles, such as X rays or electrons. Because re-emission occurs so quickly, the fluorescence ceases as soon as the exciting source is removed, unlike phosphorescence, which persists as an afterglow. A fluorescent lightbulb is coated on the inside with a powder and contains a gas; electricity causes the gas to emit ultraviolet radiation, which then stimulates the tube coating to emit light. The pixels of a television or computer screen fluoresce when electrons from an electron gun strike them. Fluorescence is often used to analyze molecules, and the addition of a fluorescing agent with emissions in the blue region of the spectrum to detergents causes fabrics to appear whiter in sunlight. X-ray fluorescence is used to analyze minerals.

* * *


Universalium. 2010.

  
Share  

Look at other dictionaries:

  • fluorescence — noun свечение, флуоресценция …   Англо-русский словарь Мюллера

  • Fluorescence — Flu o*res cence, n. [From {Fluor}.] (Chemistry, Optics) A luminescence emitted by certain substances due to the absorption of radiation at one wavelength, and the almost instantaneous re emission of radiation at another, usually longer wavelength …   The Collaborative International Dictionary of English

  • fluorescence — 1> флюоресценция, свечение …   Новый большой англо-русский словарь

  • Fluorescence — Fluorescent minerals emit visible light when exposed to ultraviolet light Fluorescence is the emission of light by a substance that has absorbed light or other electromagnetic radiation of a different wavelength.[1] It is a form of luminescence.… …   Wikipedia

  • Fluorescence — La fluorescence est une émission lumineuse provoquée par l excitation d une molécule (généralement par absorption d un photon) immédiatement suivie d une émission spontanée. Ce processus est différent de la phosphorescence. La fluorescence peut… …   Wikipédia en Français

  • fluorescence — флуоресценция dual color fluorescence двухцветовая [бихромофорная] флуоресценция integrated fluorescence of untreated cells неспецифическая [фоновая] флуоресценция интактных клеток (при разделении клеток на клеточном сортере) relative integrated… …   Англо-русский словарь по иммунологии

  • fluorescence — fluəˈresns сущ. свечение, флуоресценция Syn : luminescence флюоресценция, свечение fluorescence свечение, флуоресценция …   Большой англо-русский и русско-английский словарь

  • fluorescence — f физ. флуоресценция, свечение lampe [tube] à fluorescence лампа дневного света …   Большой французско-русский и русско-французский словарь

  • fluorescence — флуоресценция superradiant fluorescence …   Англо-русский словарь технических терминов

  • fluorescence — The emission of one or more photons by a molecule or atom activated by the absorption of a quantum of electro magnetic radiation. Typically the emission, that is of longer wavelength than the excitatory radiation, occurs within 10 8 seconds :… …   Dictionary of molecular biology