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991.
A method of calculating longevity to macrocrack development under a programmed loading in the form of a block repeated many times to failure is proposed. Relationships are derived for calculation of longevity under blocks with stepwise variation in stress amplitude, and also blocks assigned by the probability-distribution density of the stress amplitudes and tables of the differential frequency of repetition of peak and average stresses. Consideration of variation in the material's endurance limit under an irregular cyclic loading is demonstrated. It is shown that a specific type of relationships can be derived for the material under investigation with allowance for its kinetic cyclic-strain diagrams. An example of the longevity calculation, which is compared with experimental data for the block loading of steel 40Kh specimens, is cited.Translated from Problemy Prochnosti, No. 8, pp. 3–11, August, 1995.  相似文献   
992.
993.
Based on data obtained in terms of the first International cooperative program on the effects of acidic precipitations on materials (ICP Materials) of the United Nations European Commission on Economics (UN ECE), the relations between the ozone O3 and nitrogen dioxide NO2 concentrations in combination with the sunshine effect (taken into account either as the solar radiation (Rad) or the sunshine duration (Sun)) are considered. Analysis based on monthly and annual averages led to a new equation recommended for predicting ozone levels over rural, urban, and industrial areas of Europe as a function of NO2 concentration and Sun parameter. Using Rad instead of Sun provides similar results, but, for practical usage, the equation involving a more easily available parameter Sun was recommended. The new equation corrects and improves the earlier proposed one, in which the concentration of ozone was given as a function of NO2 concentration solely, and is included in the UN ECE Manual on mapping critical loads / levels and geographical areas where they are exceeded.  相似文献   
994.
The Constant Rate Thermal Analysis method has been used under different experimental conditions to obtain barium titanate powder of very small grain size. Both a crystallographic and a dielectric study ham been carried out on samples sintered at different temperatures. It is deduced that the formation of small coherently diffracting domains is improved by the generation of oxygen vacancies and the cubic phase stabilization depends on the coherently diffracting domain size rather than on the particle size.  相似文献   
995.
The strength values obtained in four series of bend tests on two monolithic ceramic materials have been statistically evaluated. Statistical mapping procedures were used to check whether a Weibull distribution fits the strength data. Where this has been found to be the case, the value of the Weibull parameters determined according to different evaluation methods fall within each other's confidence interval. The values of the modulus m and of the characteristic strength σ0 of the two-parameter distribution can differ significantly from the corresponding values in the three-parameter distribution.  相似文献   
996.
997.
Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 12, pp. 12–13, December, 1992.  相似文献   
998.
Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 11, pp. 16–17, November, 1992.  相似文献   
999.
Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 5, p. 36, May, 1992.  相似文献   
1000.
Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 10, pp. 8–10, October, 1992.  相似文献   
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