Negative luminescence

It should be mentioned that Table 3.1 gives not only references directly connected with nonequilibrium photodetectors and noise suppression, but also with related phenomena, among which negative luminescence is the most important one. For instance, the use of thermal gradient was considered connected with InSb luminescence, but not with photodetector performance. 

The next phenomenon connected with nonequilibrium methods is negative luminescence [337], also called induced absorption [338]. Actually, a semiconductor with nonequilibrium decrease of carrier concentration emits less electromagnetic radiation than it should according to the Planck law. 

P. Berdahl, V. Malyutenko, T. Morimoto, Negative luminescence of semiconductors. Infrared Phys. 29(2 ), 667-672 (1989)... 

A review pubHshed ia 1984 (79) discusses some of the methods employed for the determination of phenytoia ia biological fluids, including thermal methods, spectrophotometry, luminescence techniques, polarography, immunoassay, and chromatographic methods. More recent and sophisticated approaches iaclude positive and negative ion mass spectrometry (80), combiaed gas chromatography—mass spectrometry (81), and ftir immunoassay (82). 

Chemiluminescent compounds and their precursors in P. stipticus. Although P. stipticus is negative in the luciferin-luciferase reaction, crude extracts of this fungus are chemiluminescent, like the luciferin obtained from Ompbalia flavida by Kuwabara and Wassink (1966). The chemiluminescence is elicited by the addition of H2O2 and Fe2+ under a mild condition of pH 5-8, and the luminescence is strongly... 

Light emission from the chemiluminescent substrate is directly proportional to the amount of the target nucleic acid in the sample, and the results are recorded as relative luminescence units (RLUs). All samples, standards, and controls are run in duplicate, and the mean RLU is used in data analysis. The percent coefficient of variation (%CV) for duplicate RLU for controls and samples must be within the recommended limit for that assay for the results to be valid. For example, negative samples must have a CV of <30% and positive samples <20% in the HCV assay. 

A general feature of doped semiconductive NC materials is described in a review paper authored by Bhargava, one of the founders of this area (8). It is generally accepted that solid particles are richer in crystallographical defects when their diameter becomes smaller. Quantum size effects associated with nanoparticles are very sensitive to the defects. In most cases, defects influence negatively the luminescent properties of phosphors. Most of these drawbacks of NC phosphors are attributed to the larger specific surface area, since defects tend to concentrate themselves in a near-surface region. 

Negative Ions and Trapped Electrons. At the present time we can only speculate on the nature of electron traps in irradiated polyethylene. Partridge (33) suggests that electrons are trapped between molecular chains because luminescence in irradiated polyethylene occurs in the temperature intervals where mechanical losses occur. For large doses, free radicals, R , are abundant enough to be significant in trapping electrons. The reaction ... 

Similar behavior is observed in the potential-dependent luminescence of a ruthenium dye adsorbed to 2 [52]. Although the flat-band potential of 2 is known to shift positive in the presence of the potential-determining Li+ ion, relative to the TBA+ ion [5,68], this effect cannot explain the observed behavior. For example, in our experiments, the dye injects in both cases, but it takes a much smaller negative potential excursion to turn off the injection process in the presence of Li+ than with TBA+ [52]. This is the opposite of what would be expected if only equilibrium (i.e., dark) band edge motion were responsible for the effect. 

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