Minor defect evaluation

In the following, the quahty of epitaxial Si layers deposited either on an annealed porous Si layer or on a non-annealed porous Si layer is discussed. The epitaxial layer quality is evaluated by etch pit densities, defect densities, minority carrier lifetimes, or solar cell efficiencies. Table 1 gives an overview on the main characteristics of the epitaxial Si layers on the different types of porous silicon layers, i.e., single or double layers. 

In the case of the ASME codes for nuclear pressurised components, the questions of fatigue design and of flaw evaluation are dealt with separately in ASME Section III and Section XI Appendix A, respectively. The design S-A curve for machined butt welds typical of thick section pressurised components is set at a factor of two on stress range or twenty on cyclic life, whichever is more conservative, below the mean of S-N data developed on smooth cylindrical specimens in air. (A somewhat similar design curve obtained by a different method from experimental S-A data for machined butt welds is given in British Standard 5500.) These safety factors are intended to encompass any adverse influence of minor weld defects, size effects, data scatter and environment. As far as environmental effects are... 

Teratogenic effects of substances on test animals are evaluated from resorption (death of the conceptus), fetal toxicity (reduced body weight), aberrations (malformations), and minor anomalies. Statistical analysis is performed by surveying the four most important parameters namely, the number of litters with malformed fetuses, increase in the average number of fetuses with defects per litter, the number of resorptions, and dead fetuses. Finally, the incidence of malformation (response) is plotted against doses administered. Any dose-response relationship should indicate the teratogenicity of the chemical under experimental conditions. 

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