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Topic: Luminescence


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In the News (Thu 26 Nov 09)

  
  AllRefer.com - luminescence (Physics) - Encyclopedia
There are many types of luminescence, including chemiluminescence, produced by certain chemical reactions, chiefly oxidations, at low temperatures; electroluminescence, produced by electric discharges, which may appear when silk or fur is stroked or when adhesive surfaces are separated; and triboluminescence, produced by rubbing or crushing crystals.
Bioluminescence is luminescence produced by living organisms and is thought to be a type of chemiluminescence.
If the luminescence is caused by absorption of some form of radiant energy, such as ultraviolet radiation or X rays (or by some other form of energy, such as mechanical pressure), and ceases as soon as (or very shortly after) the radiation causing it ceases, then it is known as fluorescence.
reference.allrefer.com /encyclopedia/L/luminesc.html   (317 words)

  
 Luminescence Laboratory, Department of Earth & Environmental Sciences, UIC   (Site not responding. Last check: 2007-11-06)
A luminescence age is a measure of the time since the last sunlight exposure (or heating) event of the sediment.
The reduction in luminescence, usually by sunlight, must be related to a significant environmental event (e.g.
The luminescence dating of sediment that was exposed to little or no light during a specific event will yield a spurious age.
www.uic.edu /labs/ldrl/context.html   (225 words)

  
 Luminescence - Wikipedia, the free encyclopedia
Luminescence is light not generated by high temperatures alone.
Luminescence can be caused by chemical or biochemical changes, electrical energy, subatomic motions, reactions in crystals, or stimulation of an atomic system.
Historically, radioactivity was first thought of as a form of "radioluminescence", although it is today considered to be separate since it involves more than electromagnetic radiation.
en.wikipedia.org /wiki/Luminescence   (104 words)

  
 Luminescence Dating
Luminescence dating of sediment relies upon the fact that the geological luminescence signal of the sediment is reduced to a near-zero residual due to exposure to daylight during weathering and transport (see Aitken, 1985, 1998).
The palaeodose is evaluated by comparing the natural luminescence intensity of the sample with the increase of luminescence signal output induced by known amounts of additional radiation.
Luminescence is a property by virtue of which any material emits light in response to some external stimulation and depending upon the stimulation this method is broadly has two derivatives: 1.
www.uga.edu /osl/technique.html   (845 words)

  
 [No title]   (Site not responding. Last check: 2007-11-06)
The luminescence spectra of titanosilicate glasses, grown in a steady laser plume in an atmosphere of air or nitrogen at normal pressure, were investigated in the spectral range 260—500 nm.
The luminescence was excited by the second harmonic of a cw Ar laser (λ =257nm) and was observed for glasses synthesised in air and nitrogen atmospheres throughout the investigated range of the titanium concentrations by weight (from ~0.1% to ~6%).
When the titanium concentration was less than 1%, the luminescence spectrum of glass grown in a nitrogen atmosphere had a band with a maximum at λ ~ 280 nm associated with silicon oxygen-deficient centres and a correlated new strong band with a maximum at λ ~ 380 nm.
www.turpion.org /php/paper.phtml?journal_id=qe&paper_id=1163   (303 words)

  
 V. SOME RESEARCH RESULTS AND APPLICATIONS
Although they, or their composite signal, would be distinguishable against a background of vegetation, the contrast would not be strong against a mixture of soil and different vegetation types and conditions.
On a luminescence basis, however, the fabric has a signal intensity that not only greatly exeeeds that of soils and vegetal backgrounds, but occurs at different wavelengths--making detection a certainty if the areal extent is sufficient.
If sun induced luminesced photons are present, they will be recorded along with the reflected photons, causing a slightly higher DN value or slightly darker gray tone.
www.tec.army.mil /research/products/desert_guide/TUTORIAL/text/lt5.htm   (1039 words)

  
 Luminescence & Radiometric Dating
Luminescence is a phenomenon exhibited by many crystals, such as diamond, quartz, feldspars and calcite.
This is the fundamental process behind luminescence dating (TL and OSL), as well as electron spin resonance (ESR) dating, which uses a different technique to achieve the same result.
The advantage of ESR is that, unlike luminescence, the electrons are not evicted from their traps, so the measurement can be repeated as desired on the same sample.
www.tim-thompson.com /luminescence.html   (1399 words)

  
 Luminescence dating
The Luminescence dating facility was established in 1996 and is engaged in a range of Research, Service and Knowledge Transfer activities.
The accuracy of a Luminescence age is primarily governed by the success of the zeroing event.
Whilst recent technical developments have improved experimental errors on luminescence measurements to as little as ±1%, the precision of a luminescence age is ultimately restricted by systematic errors associated with equipment calibration.
www.glos.ac.uk /schools/environment/facilities/envirolabs/geochronlabs/luminescence/index.cfm   (528 words)

  
 The Glow of Success   (Site not responding. Last check: 2007-11-06)
Luminescence sensors do not have this problem, because the target will fluoresce in a different color when it’s struck by UV light.
Luminescence sensors can be more difficult to set up than photoelectric sensors, because the beam of UV light they emit is invisible, and the glowing spot it produces may be difficult to see with the naked eye.
Luminescence sensors are available with operating distances ranging from a few millimeters to 350 millimeters.
www.assemblymag.com /CDA/ArticleInformation/features/BNP__Features__Item/0,6493,140696,00.html   (1652 words)

  
 R & D: Luminescence enhancements critical to biotech growth: luminescence is increasing its popularity in bioscience ...   (Site not responding. Last check: 2007-11-06)
R & D: Luminescence enhancements critical to biotech growth: luminescence is increasing its popularity in bioscience applications due to added flexibility and improved detection devices.@ HighBeam Research
The ease and versatility of luminescence reactions continue to make them attractive investigative tools for researchers, especially in life science areas.
Since ATP is the luminescent reaction's limiting substance, the emitted light from these samples is directly proportional to the number of...
www.highbeam.com /library/doc0.asp?DOCID=1G1:99516036&refid=ip_encyclopedia_hf   (212 words)

  
 Luminescence dating
Luminescence dating is based on the measurement of the amount of light that is released upon thermal or optical stimulation, by minerals such as quartz and feldspar.
When they are exposed to sunlight during transportation in the air the latent luminescence signal in the quartz and feldspar grains is bleached down to a negligible level and the luminescence "clock" is set to zero.
Chronostratigraphy and luminescence dating of the aeolian deposits of the western Chinese loess plateau: a contribution to the investigation of the terrestrial record of the Quaternary climate oscillations.
allserv.rug.ac.be /~pvdhaute/lumin.htm   (867 words)

  
 luminescence on Encyclopedia.com   (Site not responding. Last check: 2007-11-06)
Luminescence enhancements critical to biotech growth: luminescence is increasing its popularity in bioscience applications due to added flexibility and improved detection devices.
Strange But True: That blue glow is just the icing on the cake LUMINESCENCE
Luminescence sensors are immune to color and contrast shifts.(Sensors and Transducers)
www.encyclopedia.com /html/l1/luminesc.asp   (470 words)

  
 Gloriana Threads - Collections
Luminescence will come in most of the same colors that our Silk Floss is available in.
Luminescence is a single strand buttonhole twist which may be used alone or multiple strands may be used to achieve the coverage your require.
To stitch with more than strand of Luminescence with the color changes lined up, place each strand next to another and move until like colors are next to each other as much as possible.
www.glorianathreads.com /Luminescence.html   (235 words)

  
 Bioglo Oxygen Luminescence
Besides oxygen, Bioglo Oxygen Luminescence also delivers superior ingredients such as vegetal complex, moisturising complex, essential oils, anti-oxidants, fruit acids and UV protection to ensure that your skin receives the best possible nourishment and moisturisation.
Bioglo Oxygen Luminescence has been formulated to be ph5.5-6 so that it can maintain the natural protective mantle of healthy skin.
Bioglo Oxygen Luminescence is, in fact, suitable for acne skin because all products in the range help to increase the level of oxygen.
proven.virtualave.net /oxygenluminescence.html   (716 words)

  
 Research projects: Aberystwyth Luminescence Research Laboratory
Such complex mixtures of grains, some of which have had their luminescence signal reset and other which have not, may exist in a range of depositional settings.
Understanding the luminescence response of natural minerals to ionizing radiation is fundamental to the succesful application of luminescence to Quaternary dating.
The Research at Aberystwyth has been crucial in improving the methods that are available within luminescence for determining the radiation dose, measured in the SI unit of the Gray (Gy), to which as sample has been exposed during burial.
www.aber.ac.uk /quaternary/luminescence/newprojects.htm   (981 words)

  
 Luminescence Research Laboratory
The Luminescence Dating Service was established in 1983 and has considerable experience in dating a wide range of archaeological materials from around the world.
The Luminescence Laboratory has an international research profile; the scope of recent work includes the physics of luminescence, development of methodologies and application to archaeological and geological samples.
Luminescence dating is applicable to samples of age in the range 50 - 500,000 years.
www.dur.ac.uk /lumin.dating/service.htm   (277 words)

  
 Banner Engineering Press Release: Advanced New Luminescence Sensors Can't Be Fooled by Color and Contrast Shifts   (Site not responding. Last check: 2007-11-06)
The QL Series sensors detect luminescence that is inherent in a material or it can sense luminophores that have been added to a material in process to make it luminescent.
"Luminescence sensors are ideal for applications requiring the detection of color marks, clear adhesive labels, tamper-evident seals, oil or grease and fluorescent product markings where the background color may vary causing a contrast change that would confuse or fool other sensing methods," said Joe Dolinsky, Technical Manager for Banner's photoelectric products.
A Quick-SET mode where the sensor is taught to detect the specific luminescence intensity of a target and ignore the less-intense background, and a Fine-Detect mode that increases the unit's sensing precision to detect the specific luminescence intensity of a target and ignore all other surfaces with more or less luminescence.
www.bannerengineering.com /whats_new/release.php?id=66   (471 words)

  
 Luminescence Dating   (Site not responding. Last check: 2007-11-06)
The amount of luminescence emitted is proportional to accumulated dose and with the annual dose an age can be determined.
The calculated age is the time elapsed since the sample was buried as sunlight bleaches away the luminescence signal so resetting the 'time clock'.
Luminescence expertise from both the Oxford and Sussex luminescence laboratories have been drawn on in the setting up and running of the SCIDR luminescence dating facility.
www.shef.ac.uk /uni/academic/I-M/idry/lumindat.html   (302 words)

  
 Methods: Luminescence Dating Laboratory
Luminescence dating is an alternative to radiocarbon dating, when no organic material (bone, seed, wood, etc.) is available, or if the expected age is greater then the limits of radiocarbon dating of about 40,000 years.
Luminescence dating can be applied to establish the age of archaeological or geological sites, by dating ceramics or rocks (must have been heated) or certain soils or sediments.
In general, the method used for measuring the luminescence in the laboratory is similar to the way the ‘Luminescence Clock’ had been set to zero in the past.
www.eva.mpg.de /evolution/files/methods.htm   (481 words)

  
 Powerful visible (530–770 nm) luminescence in Yb,Ho:GGG with IR diode pumping
Powerful visible luminescence in a Gadolinium Gallium Garnet (GGG) crystal, co-activated with Yb3+ (~15 at.%) and Ho3+ (~0.1 at.%) ions, is investigated under CW laser diode pumping (λ = 938 and 976 nm).
Analysis of the crystal absorption and luminescence spectra allows one to conclude that Yb3+ - Ho3+ stepwise up-conversion is the mechanism explaining the phenomenon.
Ho3+ ions embedded in the crystal in small concentration are shown to form an effective reservoir for energy transferred from the excited Yb3+ subsystem and to be an efficient source of the visible emission.
www.opticsexpress.org /abstract.cfm?URI=OPEX-10-16-832   (737 words)

  
 LANL OSL Home   (Site not responding. Last check: 2007-11-06)
Research conducted in the EES-10 Luminescence Geochronology Lab (LGL) is directed towards advanced geologic applications of and technique development for luminescence dating.
The LANL Luminescence Geochronology Lab is currently the only facility in the North America to have single-grain OSL measurement capacity.
Luminescence dating was recently highlighted in a feature article, "Physics and Archaeology" in the October 2001 issue of Physics Today, a publication of the American Institute of Physics.
www.ees10.lanl.gov /osl/OSL_home.htm   (378 words)

  
 Triboluminescence (from luminescence) --  Encyclopædia Britannica   (Site not responding. Last check: 2007-11-06)
Closely related are the faint blue luminescence observable when adhesive tapes are stripped from a roll, and the luminescence exhibited when strontium bromate and some other salts…
It is in contrast to light emitted from incandescent bodies, such as burning wood or coal, molten iron, and wire heated by an electric current.
Luminescence may be seen in neon and fluorescent lamps; television, radar, and X-ray fluoroscope screens; organic substances such as luminol or the luciferins...
www.britannica.com /eb/article-68946?tocId=68946   (662 words)

  
 Introduction to Aberystwyth Luminescence Research Laboratory
Luminescence dating is a Quaternary dating method used to determine the age of a sample.
The luminescence dating laboratory in Aberystwyth is part of the Institute of Geography and Earth Sciences in the
Within the Aberystwyth luminescence laboratory the majority of our luminescence measurements are made on automated systems built at Risø National Laboratory, Denmark.
www.aber.ac.uk /~qecwww/luminescence/aberlum.htm   (277 words)

  
 Luminescence Aids Detection of Toxic Leaks - December, 1999   (Site not responding. Last check: 2007-11-06)
Researchers in the chemistry division of the Argonne National Laboratory have found luminescence to be an effective way to detect uranyl fluoride, which forms when UF reacts with atmospheric water, indicating a cylinder leak.
Inspectors now use visual inspection and ultrasonic measurement of wall thickness, but both methods are time-consuming, and visual inspection is prone to error, said James V. Beitz, leader of the research team at Argonne.
When the shutter opens, the array records a wavelength-resolved digital image that shows the location of uranyl fluoride luminescence, if present, on the surface of a UF storage cylinder.
www.photonics.com /spectra/tech/XQ/ASP/techid.723/QX/read.htm   (391 words)

  
 The Hutchinson Dictionary of Science: luminescence@ HighBeam Research   (Site not responding. Last check: 2007-11-06)
Emission of light from a body when its atoms are excited by means other than raising its temperature.
Short-lived luminescence is called fluorescence; longer-lived luminescence is called phosphorescence.
When exposed to an external source of energy, the outer electrons in atoms of a luminescent substance absorb energy and 'jump' to a higher energy...
www.highbeam.com /library/doc0.asp?DOCID=1P1:28918391&refid=ip_encyclopedia_hf   (144 words)

  
 Luminescence and incandescence (from luminescence) --  Encyclopædia Britannica
As mentioned above, luminescence is characterized by electrons undergoing transitions from excited quantum states.
The excitation of the luminescent electrons is not connected with appreciable agitations of the atoms that the electrons belong to.
More results on "Luminescence and incandescence (from luminescence)" when you join.
www.britannica.com /eb/article-68940?tocId=68940   (716 words)

  
 Journal of Luminescence.   (Site not responding. Last check: 2007-11-06)
E.I. Rashba, Luminescence and spectroscopy, Journal of Luminescence 100 (1-4) (2002) pp.
Juzeliunas, Microscopic analysis of spontaneous emission in absorbing dielectrics, Journal of Luminescence 76-77 (0) (1998) pp.
Hangleiter, Optical properties and polarization fields in the nitrides, Journal of Luminescence 87-89 (0) (2000) pp.
www.elsevier.com /cdweb/journals/00222313/viewer.htt?viewtype=keywords&rangeselected=195   (705 words)

  
 Luminescence   (Site not responding. Last check: 2007-11-06)
All of the synthesized compounds gave luminescence in Me SO and most of their chemiluminesce spectrum was identical to the fluorescence spectrum of the amide anions.
Conjugation at the 6 position of imidazopyrazinone had little effect on luminescence colour whereas conjugation at the 8 position gave a larger shift in luminescence.
The reaction rate of the alkynyl derivatives under basic conditions was slower than that under acidic conditions, whereas basic conditions enhanced the luminescence rate of the other imidazopyrazinones.
www.ch.ic.ac.uk /ectoc/echet96/papers/055/ref/6.html   (271 words)

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