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21.
22.
在直动从动件盘形凸轮的设计中,减少推程压力角可改善凸轮的受力条件,适当的偏置可以减少压力角。本文通过计算机设计方法来确定具有最小凸轮机构尺寸时的最佳偏距。 相似文献
23.
Tensile impact experiments of EC8.0−24×7 glass fiber bundles at different low temperaturesT(14°C, −40°C and −10°C) and strain rates ɛ were carried out, and complete stress-strain curves were obtained. Within the range
of the experiment temperatures and strain rates, it is found that the initial modulusE, the ultimate strength σmax and the unstable strain ɛ
b
of the glass fiber bundles all increase with ɛ at an identicalT. At an identical ɛ, with the decrease ofT, E and σmax increase; but ɛ
b
increases when 10°C>T>−40°C and decreases when −40°C>T>−100°C. The strain-rate- and temperature-dependent bimodal Weibull statistical constitutive theory was adopted for the statistical
analysis of the experimental results, and the Weibull parameters of single fiber were obtained. The results show that the
bimodal Weibull distribution function is suitable to represent the strength distribution of the glass fiber at low temperature
and different strain rates. The differences in the mechanical properties between EC8.0−24×7 and EC5.5−12 ×14 glass fiber bundles
were also discussed.
Project supported by the National Natural Science Foundation of China (No. 19772058). 相似文献
24.
The aim of this study is to identify the brain activity associated with amphetamine craving for understanding the neurobiology of addiction by watching pictures of happy, sad or amphetamine. Brain activity was measured in 12 amphetamine addicts and 12 healthy subjects by fMRI while the subjects watched pictures designed to elicit happy feelings, sad feelings, or the desire to use amphetamine. The result demonstrated that amphetamine cues led to abnormally high cingulate and low frontal lobe activation in amphetamine addicts, who showed abnormalities in affect-related brain activation. 相似文献
25.
26.
将快速傅里叶变换技术和数字滤波器设计技术应用于铝电解过程控制信号的滤波与噪声解析模型中,在160kA中间点式下料预焙槽上的试验结果表明了模型的有效性。 相似文献
27.
估计两个单属性关系在连接属性上取相同值的个数的方法有两种:静态估计法和动态估计法.本文利用不精确性推理模型对这两种方法的可信度定量地进行讨论,并用具体例子进行说明. 相似文献
28.
本文在系统阐述当代跨国经营战略调整与发展趋势的基础上,简要剖析了现阶段我国企业跨国经营的主要问题,重点探讨了我国跨国企业发展战略的基本构想。 相似文献
29.
Qingxue Huang 《Journal of Graph Theory》1991,15(1):1-6
Graham and Pollak [3] proved that n ?1 is the minimum number of edge-disjoint complete bipartite subgraphs into which the edges of Kn can be decomposed. Using a linear algebraic technique, Tverberg [2] gives a different proof of that result. We apply his technique to show that for “almost all n,” ? (n + m ?3)/(m ?1) ? is the minimum number of edge-disjoint complete m-partite subgraphs in a decomposition of Kn. 相似文献
30.
A theoretical equation has been developed to described the rate of slow crack growth in an ethylene-hexene copolymer in terms of the basic morphological parameters. These parameters are spacing of the butyl branches, number of tie molecules, and the thickness of the lamellar crystal. Experimentally, the thickness of the lamellae and the long period were determined as functions of the branch density. The calculation of the number of tie molecules is based on the values of the molecular weight and the long period. The model of slow crack growth is based on the rate of disentanglement of the tie molecules. The rate of disentanglement varies inversely with the number of tie molecules and directly with the number of tie molecules that are not pinned by the branches. 相似文献