Illumination intensity, effects

Up to date, the importance of illumination intensity has been paid little attention. According to the results obtained, (Br ) and (CT) were noticeably affected by the illumination intensity, although this was not the case for iodide ions. The ascending trend of (X ) observed with increasing ip, which was invariant with changing the rotation rate of the electrode, is believed to reflect an illumination intensity effect. 

For current densities below JPS the photocurrent in aqueous HF is found to be increased by a factor of 2 or even up to a factor of 4 for small photocurrent densities [Br2, Mai, Pel]. This effect is shown in Fig. 4.13. For non-aqueous HF electrolytes factors between 2 and 3 are observed. For further reduction of the illumination intensity the multiplication factor approaches infinity, because of the illu-... 

A single-beam spectrophotometer, hke the one shown in Figure 1.5(a), presents a variety of problems, because the spectra are affected by spectral and temporal variations in the illumination intensity. The spectral variations are due to the combined effects of the lamp spectrum and the monochromator response, while the temporal variations occur because of lamp stability. 

Fleet, C. F. and Siebert, K. J. (2005). Effect of illumination intensity on visual perception of turbidity. Food Qual. Pref. 16, 536-544. 

Fig. 2.12 Verification of the photocatalytic decomposition effect for exhaust compounds from a diesel engine in the laboratory (UV illumination intensity in the range of 280-380 nm was ca. 10 UW cm-2 for 8 h) (taken from Ref. 40).

The illumination intensity was found to influence on the degree of competition, and the effects were different among the kind of... 

The effect of illumination on the I-V curves of both p-Si and n-Si is shown in Fig. 3.13. The anodic reaction kinetics of/ -type silicon are not affected by illumination because the reaction consumes holes which are the majority carriers and their concentration is little affected by illumination. For n-Si during anodization, tbe interface is reversely biased and in order to sustain the reaction, either holes have to be generated or electrons have to be injected from the electrolyte. Thus, in the dark, an extra voltage, Vexj above that which is required for anodization of p-Si, is needed to drive the current. For example, about 100 V is required for 7mA/cm initially in NMA. The extra voltage needed to anodize -Si diminishes with increasing illumination intensity and at sufficient light intensity the anodic current becomes identical to that for p-Si. The quantum yield of illuminated anodization is low a value as low as 1% has been found for the anodization of silicon under illumination. ... 

FIGURE 5.23. Summary of effective dissolution valence and hydrogen evolution efficiency as a function of potential for different materials and illumination conditions. L is illumination intensity. 

As discussed in Chapter 5, the effective dissolution valence of silicon, n, can vary between 2 and 4 depending on the type of silicon, potential, and illumination intensity. In general, n increases with increasing anodic current density for all types of silicon substrates as shown in Fig. 5.21. The value of n sharply changes at the peak current... 

For p-Si in the PS formation region, n tends to increase with doping concentration particularly at high doping concentrations as shown in Fig. 8.8 for n-Si the effect of doping concentration on dissolution valence is seen to depend on current density. It decreases with increasing illumination intensity as shown in Fig. 8.9. Substrate orientation has little effect on n as shown in Fig. 8.10. ° ... 

Further research in the area of SORS led to the development of a more effective SORS modality, termed inverse SORS. This improved concept removes some of the artifactual limitahons inherent to the conventional SORS approach, and permits the use of higher laser powers through the provision of a wider illumination zone at the sample. This is beneficial in applications where maximum illumination intensity limits exist, such as when probing living tissue in vivo and in explosive powder environments. 

Figure 90. Effect of illumination intensity on the degradation of menatetrenon (25°C). Light source White fluorescent lamp. (Reproduced from Ref. 407with permission.)...

One way to determine if the light intensity is sufficient to flatten the bands is to plot OCP versus illumination intensity (Fig. 6.3). For a material that does not experience significant Fermi level pinning [3,4], a sufficiently intense illumination would saturate the OCP, where additional illumination has a negligible effect on OCP. It may take a few to tens of seconds or more (this is materials dependent) to... 

For thick multilayer structures, the variation of the HF concentration can cause a porosity gradient along the depth. This effect is more prominent in n-type due to the added effect of the decrease in the illumination intensity. The variation of the HF concentration has been attributed to the problems... 

Liquid crystal displays (LCDs) have many advantages over other display types. They are flat and compact, possess extremely low-power consumption (microwatts per square centimeter in the case of the twisted nematic effect), their color and contrast does not fade with an increase in the illumination intensity, they work both in transmissive and reflective modes in a wide operating temperature range and with a long lifetime. Besides that, LCDs are the most economically produced flat display systems. LCDs have... 

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