Effect of austenite grain size and accelerated cooling start temperature on the transformation behaviors of multi-phase steel

The transformation behaviors and microstructures of a low carbon multi-phase steel were investigated by the simulation of deformation-relaxation-accelerated cooling processing,using a Gleeble 3500 thermal-mechanical simulator.A pre-treatment of solid solution at 1200°C was implemented to minimize the influence on transformation from solid solution/precipitation qualities of 0.08%Nb in this steel.On this basis,the effect of austenite grain size and accelerated cooling start temperature were studied individually.The results indicated that the transformation of ferrite in multi-phase steel could be significantly promoted by the refinement of austenite grains and the increase of relaxation time,while the hard phase,such as lath bainite or martensite,could still be obtained with the following accelerated cooling.In contrast,more uniform lower temperature transformed microstructure could form from coarse grain austenite.The potential benefit of austenite grain size on adjusting the proportion of phases in multiphase steel was also discussed.     

军校营造良好学风的几点思考

针对当前军校学风建设存在的问题,从加强思想教育、完善教学管理制度、发挥队干部良好的导向作用、加强教风建设及落实教学管理制度等方面提出了军队院校营造良好学风的对策.     

关于复正规矩阵的Rayleigh商

将Hermite矩阵的Rayleigh商推广到了复正规矩阵中,研究了复正规矩阵的Ray-leigh商的一些性质,其结果具有一定的理论价值和应用价值。     

执政党建设与当代执政文化转型

着重研究了马克思主义执政党建设如何应对当代世界政党政治的执政文化转型问题,认为应当正确认识和处理马克思主义执政党建设与当代世界政党政治的关系,深入研究世界上其他执政党治国理政的成功经验和有益做法,不断提高马克思主义执政党的执政能力和科学化水平。     

时空结构视野下旅游客源市场定量初探——以浙江嘉兴乌镇为例

在客源时间分布上,计算乌镇游客游览时间强度指数,得到游客游览时间主要集中在二、三季度,并以7、8月份为最高峰。而在客源市场的分布上,鸟镇已经形成了以浙江为核心,上海、北京等地为一级,安徽、河南等地为二级的国内客源市场。在长三角古村落旅游发展迅速的今天,乌镇与周边的周庄、同里等古镇的竞争日益激烈,而旅游产品的创新、加大宣传迅速占领国内二级客源市场等措施将有助于乌镇在竞争中脱颖而出,占领主导地位。     

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.     

超细片状铝粉和铝银浆的制备

超细鳞片状铝粉和铝银浆由于其特殊的二维平面结构，具有良好的遮盖力、显著的屏蔽效应、光学反射能力；超细鳞片状铝粉和铝银浆颜料的制备方法很多，本文采用机械化学法制备超细鳞片状铝粉和铝银浆。     

ZF12-145(L)气体绝缘金属封闭开关设备断路器

介绍了ZF12-145（L）三相共箱式气体绝缘金属封闭开关设备断路器的技术参数、性能、灭弧室的计算分析和主要特点.     

自主知识产权是提升国家竞争力的核心

科学技术是第一生产力,自主创新是第一竞争力,只有加强自主知识产权的保护,才能调动和保护人们自主创新的积极性,开发更多更高质量的自主知识产品,提高我国经济的国际竞争力,为我国在国际经济竞争中争取主动权。     

一族新颖的ZCS-PWM变换器的研究

分析了一个新的零电流开关（ZCS）单元电路的特性。基于这个ZCS的单元电路，构建了一个新的ZCS的Boost电路，并对他们的工作机理进行了分析，而且在这个ZCS单元电路的基础上构建出更多的ZCS变换器。实验和仿真结果验证了理论分析。