Luminescence dose dependence

The time (or dose) dependences of the subbands turned out to be a very precise and sensitive tool to study the defect formation, and STE can be used to both trigger and probe the dynamics of lattice rearrangement in RGS. Figures 5 and 6 show examples of evolution of luminescence spectra of RGS under irradiation by electrons (Fig.5) and photons (Fig.6). In all cases a pronounced increase in the intensity of the defect component during... 

In the region where the reciprocal approximation holds, Equation 7 also predicts that the intensity is independent of dose. It is found, however, that the intensity is proportional to dose. This dose dependence could arise in this kinetic scheme if the species causing luminescence are in non-overlapping clusters or spurs and an increase in dose simply results in a proportionate increase in the number of such clusters. However, this cluster model would imply that virtually all triplets must be formed in the clusters, and there is as yet no other evidence for this. 

In contrast to ascorbic acid and a-tocopherol amidothionophosphates did not have any prooxidative effects as measured by oxygen consumption from buffer solutions containing the drug and cupric sulphate as a source of redox-active metal ions (Ti-ROSH et al. 1996). Amidothionophosphates reduced significantly and in a dose-dependent manner the oxygen burst in human neutrophils as measured by luminol-dependent luminescence, and they also markedly depressed the killing of human fibroblasts by mixtures of glucose oxidase and streptolysin S. The toxicity of these molecules was tested by intraperitoneal injection of doses up to 1000 mg/kg to white Sabra mice. No mortality was observed 30 d after administration of up to 500 mg/kg. 

In an in vitro granulocyte test system according to Brandt, the Dodonea saponins (29-30) showed a dose-dependent enhancement of phagocytosis up to 25%, while a phagocytosis-independent increase of luminescence of 65% was seen in the chemiluminescence test [53]. 

Fig. 9. Dependence of the luminescence intensity at 78 K on the 28Si+ implantation dose.

The composite first-order kinetics of this pair-wise recombination leading to luminescence is demonstrated by the fact that the fraction of the total light emitted at a given temperature depends neither on the dose nor on the initial acridine concentration (Fig. 35). The number of ion pairs formed per unit weight is a function of the absorbed dose but the acridine concentration determines their nature. 

OSL processes after UV light irradiation in AIN ceramics were studied in a number of our papers [30,32,36,37]. Under optical stimulation - illumination with visible or IR light - the OSL signal occurs as a decaying pulse of luminescence. Intensity and decay time of the particular OSL pulse depends both on previous irradiation dose and intensity and wavelength of the stimulation light. 

The dose response relationship between seven commonly used herbicides and four luminescence-based bacterial biosensors was characterised. As herbicide concentration increased the light emitted by the test organism declined in a concentration dependent manner. These dose responses were used to compare the predicted vs. observed response of a biosensor in the presence of multiple contaminants. For the majority of herbicide interactions, the relationship was not additive but primarily antagonistic and sometimes synergistic. These biosensors provide a sensitive test and are able to screen a large volume and wide range of samples with relative rapidity and ease of interpretation. In this study biosensor technology has been successfully applied to interpret the interactive effects of herbicides in freshwater environments [12]. 

Another potential application is using PS as a template for various scintillation materials. For example, the dosimeter based on TL of InxTli xI nanostructures synthesized in PS voids and exposed to hard y-radiation ( Co) was studied (Franiv et al. 2004). It was shown that the integrated emission intensity depends on the size of nanocrystals and luminescence yield of TL linearly increases with the increasing dose absorbed in the eiystal (Fig. 8). 

Luminescence dahng can reachback to the earhest pottery, at about 10,000 yr ago, and beyond. How much beyond depends on the minerals concerned and the armttal radiation dose rate at a specific site. For quartz, the onset of saturation is hable to occur around 50,000 to 100,000 yr ago, and sooner for clay of high radioactivity. TL mea-suremerrts are particularly apphcable in this case since the everrt being dated is the last heating of the sample in a kiln, oven, or fireplace. 

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