• WordNet 3.6
    • n fluorescence light emitted during absorption of radiation of some other (invisible) wavelength
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Webster's Revised Unabridged Dictionary
    • n Fluorescence (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 re-radiation stops almost as soon as the incident radiation is halted, thus distinguishing this phenomenon from phosphorescence, in which re-radiation of light may continue for some time after the incident radiation is halted.The color of the radiated light typically differs from the apparent color of the material, as when green crystals of fluor spar afford blue reflections. It is due not to the difference in the color of a distinct surface layer, but to the power which the substance has of modifying the light incident upon it, by first absorbing the light to achieve an excited state, and then radiating light to resume the ground energy level. The light emitted by fluorescent substances is in general of longer wavelength than the incident light. The radiation can also be induced by ionizing radiation which is not electromagnetic, such as alpha or beta rays, and cathode rays. This property is possessed by fluorspar, uranium glass, sulphide of calcium, and many other substances. It finds use in analytical instruments to detect or measure radiation, and in some commercial applications.
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Century Dictionary and Cyclopedia
    • n fluorescence The property possessed by some transparent substances of becoming self-luminous while they are exposed to the direct action of light-rays. See phosphorescence. It is especially excited by the violet and ultra-violet rays of the spectrum, and is explained by the change in refrangibility (that is, wave-length) of the incident rays by the substance under experiment. Thus, if a beam of sunlight fall upon a solution of esculin or sulphate of quinine, its path through the liquid is marked by a bluish opalescent light. Again, if a paper moistened with the solution is exposed to the ultra-violet rays of the spectrum, it becomes blue, since these rays are diminished in refrangibility so as to become visible; by this means the ultra-violet spectrum (given by prisms of quartz) can be studied. The delicate blue surface-color of some fluor-spar and the yellowish-green surface-color of glass colored with uranium oxid (canary glass) are phenomena of the same nature. For some years previous to 1852 the phenomenon was termed epipolic dispersion.
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Chambers's Twentieth Century Dictionary
    • Fluorescence a peculiar blue appearance exhibited by certain substances exposed to sunlight, and especially observable in a dilute solution of sulphate of quinine
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Webster's Revised Unabridged Dictionary
From Fluor
Chambers's Twentieth Century Dictionary
A name given by the alchemists to all mineral acids because of their fluidity, from L. fluĕre, to flow.


In literature:

Then, nearer, I perceived a strange light, a pale, violet-purple fluorescent glow, quivering under the night breeze.
"The War of the Worlds" by H. G. Wells
They gave him some pink fluid with a greenish fluorescence and a meaty taste, and the assurance of returning strength grew.
"When the Sleeper Wakes" by Herbert George Wells
First the eyes rested upon a broad band of fluorescent amethyst, ringing the entire rocky wall.
"The Metal Monster" by A. Merritt
All animal infusions show this fluorescence.
"Six Lectures on Light" by John Tyndall
Glass may be rendered fluorescent, as is seen in the Geisler and Crookes tubes.
"Notable Events of the Nineteenth Century" by Various
A fluorescent liquid was prepared in large quantities.
"Artificial Light" by M. Luckiesh
For a second or so after he snapped it nothing happened, and then the darkness was broken by the flickering of fluorescent tubes.
"Murder in the Gunroom" by Henry Beam Piper
Next, after the drapes were opened again and the overhead fluorescent lights switched on, Mr.
"Tom Swift and The Visitor from Planet X" by Victor Appleton
As he drew nearer, he saw that the lights seemed to be fluorescents.
"The Sky Is Falling" by Lester del Rey
The fluorescence from them streamed along our hull and down past the stern, like twin rocket tails.
"Wandl the Invader" by Raymond King Cummings

In news:

Initial observations and laboratory results from UV research during 2009-10 winter bat surveys in New Jersey and Pennsylvania demonstrated that WNS-positive bat tissue fluoresces when exposed to a narrow spectrum of long-wave UV light .
Industrial Tech Guide for Ultrasonic Testing and X-ray Fluorescence.
The bags , in neutral colors and fluorescent shades, start at about $130.
The program provides for safe disposal and recycling of fluorescent light bulbs , which are energy-efficient but contain mercury and are dangerous when broken.
Under the program, collection, transport, and recycling of burned-out residential fluorescent lights will start on January 1st.
The LED bulbs in the ignition are instantaneous, while the most common fluorescent bulbs take some time to fully operational.
The LED bulbs in the ignition are instantaneous, while the most common fluorescent bulbs will take some time to become fully operational.
Compact fluorescent bulbs that produce light equivalent to 100-watt bulbs have been available for a few years and cost as little as $4 each.
While it is illegal for commercial entities to throw fluorescent bulbs away, residential light bulbs containing mercury are given a free pass to the trash.
In 2009 when the county started taking bulbs in Haywood County, its facilities collected about 5,000 feet of fluorescent light bulbs .
Fluorescent lights make up a flower.
They wanted to scrap everything about the massive, industrial-style kitchen with its fluorescent lighting, dysfunctional layout and 1980s look.
Fluorescent pH-sensitive nanoparticles indicate bacterial growth.
Parábola fluorescent-lit mirror in matte white polyurethane by B.
A Magical Nighttime Journey Through a Fluorescent Reef.

In science:

Three beam profile monitors (YAG screens) were placed upstream of the ODTR interferometer and one beam profile monitor (fluorescence screen) downstream.
Interference of diffraction and transition radiation and its application as a beam divergence diagnostic
Fluorescence emission and inner shell absorption are unique X-ray signatures which can be observed from gas under a wide range of conditions, including neutral or near-neutral gas.
Atomic Data for X-ray Astrophysics
Rosado et al., Proc. of the 5th Fluorescence Workshop, Nucl.
Air Fluorescence Relevant for Cosmic-Ray Detection - Summary of the 5th Fluorescence Workshop, El Escorial 2007
Sakaki et al., Proc. of the 5th Fluorescence Workshop, Nucl.
Air Fluorescence Relevant for Cosmic-Ray Detection - Summary of the 5th Fluorescence Workshop, El Escorial 2007
Keilhauer et al., Proc. of the 5th Fluorescence Workshop, Nucl.
Air Fluorescence Relevant for Cosmic-Ray Detection - Summary of the 5th Fluorescence Workshop, El Escorial 2007