A kind of carbon whiskers in new structure and morphology

Carbon whiskers with new structure and morphology were observed when heating the milled graphite. Transmission electron microscopy (TEM) and high resolution electron microscopy (HREM) show that carbon layers are almost perpendicular to the growth axes of carbon whiskers. Field emission scanning electron microscopy (FESEM) indicates that there are spirals appearing on the surface of the whiskers. The structure analysis shows that the growth mechanism of carbon whiskers is related to the trace amount of ZrC in the heated samples.     

一种具有新颖结构和形态的炭须

在高温处理球磨过的石墨材料时,发现了一种结构和形状新颖的炭须.透射电子显微术(TEM)和高分辨透射电子显微术(HREM)证实其石墨片层几乎垂直于炭须的轴向.场发射扫描电子显微镜(FESEM)发现其表面具有螺旋结构.结构分析证明这种螺旋状炭须生成机理同高温处理后的炭材料中含有的微量碳化锆有关.     

复杂载荷下疲劳寿命的估算

本文讨论在复杂载荷下疲劳(裂纹形成)寿命的估算方法。文中首先着重介绍局部应力-应变法的原理和应用,并通过带孔铝合金试件在随机载荷谱下的疲劳寿命计算实例加以具体说明。其次,本文还用传统的名义应力法作了疲劳寿命估算。对名义应力法,文中用了随机(块)谱及变均值、常均值、等损伤、主峰值等程序块谱。最后,本文把按局部应力-应变法及名义应力法所得疲劳寿命计算结果与已有的试验结果进行了分析比较。     

Coefficient of Partial Correlation and Its Calculation

This thesis offers the general concept of coefficient of partial correlation. Starting with regression analysis, the paper, by using samples, infers the general formula of expressing coefficient of partial correlation by way of simple correlation coefficient.