冲出锥

Based on the contacting characteristics of the surfaces in MEMS, we use the continuum contact mechanics modeling and fracture mechanics concepts to give a closed-form solution for the adhesion of the flat-ended wedges, including the atomic pressure distribution, the variations of the contact area and air gap with the load.

基于MEMS表面的接触力学特点，本文运用连续介质接触力学及断裂力学方法，研究了平底锥冲头的粘着接触问题，给出了接触区的原子压力分布、接触面积和表面间隙随载荷变化的封闭解。

The results show that, for the elasto-plastic contact of tip-substrate approach and separation process, the material plastic yielding in the atomic level is still governed by the von Mises criterion. For the adhesion of flat-ended wedges, continuum mechanics can be still applied down to a few lattice constants within the contact region, and give reasonable results, apart from the discrepancies near the contact edges. Moreover, adhesion hysteresis occurs during unloading due to the atomic steps, where the unloading curve does not coincide with the loading one. This in turn supports the presumption proposed by Pollock for the adhesion of stepped spheres.

本文首先对针尖—基体模型的弹塑性接触机理进行了深入研究，指出在原子水平上材料的塑性屈服仍由Von Mises准则控制；对平底锥冲头粘着接触的模拟表明，除了在接触区边缘附近有一定差别外，接触力学方法在接触区内几个晶格常数范围内仍能给出令人满意的结果；由于原子台阶效应，加载与卸载曲线不重合，出现粘着滞后，证实了Pollock关于具有纳米阶梯结构的球体粘着滞后现象的推测。

The absorption and distribution of chromium were studied in ryeusing nutrient culture technique and pot experiment.

采用不同浓度K2CrO4(0，0.4，0.8和1.2 mmol/L)的Hoagland营养液处理黑麦幼苗，测定铬在黑麦体内的亚细胞分布、铬化学形态及不同部位的积累。

By analyzing theory foundation of mathematical morphology in the digital image processing, researching morphology arithmetic of the binary Image, discussing two basic forms for the least structure element: dilation and erosion.

通过分析数学形态学在图像中的理论基础，研究二值图像的形态分析算法，探讨最小结构元素的两种基本形态：膨胀和腐蚀；分析了数学形态学复杂算法的基本原理，把数学形态学的部分并行处理理念引入到家实际应用中。