Surface energy-driven adhesion of two opposing microcantilevers

Summary This paper studies surface energy-driven adhesion of two parallel microcantilevers oriented in opposite directions. Adhesion becomes possible when an attached state of the two opposing cantilevers becomes an equilibrium state at which the release rate of the strain energy with respect to the attached length is equal to the surface energy per unit length. The analytical model developed here predicts that the critical values of surface energy for initial adhesion and full adhesion of two opposing cantilevers increase monotonically with increasing overlap length. This is attributed to the fact that increasing overlap length leads to a decrease in the unattached suspended length of the cantilevers and then an increase in the release rate of the strain energy, which requests a higher surface energy for adhesion of the two cantilevers. Therefore, the strength of two opposing cantilevers against adhesion can be enhanced by increasing the overlap length. When adhesion occurs, because of lower surface energy and shorter attached length, the attached state of two beams of small or moderate overlap length always has a higher total energy than the unattached straight beams before the full adhesion is reached. On the other hand, because of higher surface energy and longer attached length, the total energy of the attached state of two beams of large overlap length can be lower than the total energy of the unattached straight beams even before the full adhesion is reached. In particular, for the first time to our knowledge, the present results show quantitatively how much the critical values of surface energy density for adhesion of two opposing cantilevers are lower than the critical values of surface energy density for adhesion of a single cantilever attracted by a rigid substrate or other similar problems studied in the literature. These results could have significant consequences to MEMS design especially for combdrive technology.     

数字电影3D技术浅析

本文介绍目前数字电影3D技术的最新进展，分析了数字3D放映技术的分类、特点及其适用范围，举例阐明主动立体放映技术，并讨论了数字3D技术的应用前景。     

2001年绵阳科学城地区辐射环境监测与质量评价

2001年绵阳科学城地区主要环境介质(大气、河水、土壤和沉降等)中放射性水平与科学城开工前天然本底辐射没有显著性差别。通过对每个核设施烟囱流出物的测量与估算,获得了烟囱排放源项数据。利用该地区的大气扩散模式和多烟囱排放的剂量叠加原理,在评价坐标系中计算了叠加剂量分布。辐射环境质量评价表明80km范围内最大个人有效剂量是公众剂量限值的十万分之四,健康危害是危害约束值的千万分之二。表明环境影响是微弱的,是人们可以接受的。     

基于Agent的遗传算法描述与演化模型研究

Agent是指具有智能的人或其它智能物.它具有自治、反响、推测、协作、自学习和相互学习等能力,本文基于Darwin自然进化论与Mendel遗传变异理论,给出Agent的遗传算法与演化模型.这些理论的提出,进一步丰富和完善了Agent的研究内容.     

ATM/SDH接口的管理:CLR QoS的在线监测

通信网的管理对服务质量至关重要。在实际的网络中,需要对各个子网和网络单元进行良好的管理和控制。 文章从系统的角度分析了ATM/SDH接口的管理,并着重讨论了CLR QoS在线监测问题。     

导控溢流阀动态数学模型的建立及动态性能分析

分析了导控型溢流阀的动态特性，建立了其运动状态的数学模型，并对微分方程进行拉氏变换，得出了动态系统的方框图。     

Influence of interfacial strength on the fracture toughness of glass-ceramic matrix composites

Nine kinds of glass-ceramic matrix composites with different compositions and interfacial strength (τ _s) were prepared. The influence of τ _s on the fracture toughness(K _1c) of composites was studied. It was discoved that, for the system no chemical reaction taking place at the interface, K _1c increased proportionally with τ _s increasing at the first stage, then decreased when τ _s reached a certain value. According to this result, a model of relationship between τ _s, thermal mismatch (Δα _r) and K _1c was built up. If a chemical reaction took place and a new phase was formed in the interface, the K _1c of composite was effected by the combination of τ _s, chemical bonding, radial interfacial stress and other factors. Project supported by the National Natural Science Foundation of China Synopsis of the first author Wang Lingsen, professor, born in 1938, current research field: special ceramic and ceramic matrix composite, etc.     

激光三角法位移传感器测头设计

本文以直射式激光三角测头为例,导出了满足Scheimpfiag成象条件下的待测面位移与象位移间的准确关系,作为仪器结构参数设计的基础,并对提高测量精度和实用性的各项改进设计进行了分析。