Deflections of Nanowires with Consideration of Surface Effects

The elementary beam model is modified to include the surface effects and used to analyze the deflections of nanowires under different boundary conditions. Tile results show that compared to deflections of nanowires without consideration of surface effects, the surface effects can enlarge or reduce deflections of nanowires, and nanowire buckling occurs under certain conditions. This study might be helpful for design of nanowire-based nanoelectromechanical systems.     

有边界条件的忆阻元件模型及其性质

对第四类基本电路元件——忆阻元件的基本特性进行了研究,分别建立了无边界条件和有边界条件的忆阻元件的积分形式的数学模型.对有边界条件的数学模型进行了仿真,分析了有边界条件下电源频率和掺杂比、初始掺杂宽度等模型参数对电流、电压电流关系、磁链电荷关系等元件特性的影响,得出了相关的结论. 关键词： 忆阻元件 边界条件 数学模型 性质     

双凹盘形解开口膜泡形状的解析法研究

随着开口膜泡在实验上的发现,对开口泡形状的数值及解析研究逐渐成为该领域的一个热点.讨论了如何由欧阳双凹盘形闭合解构造开口泡的解析解的问题.首先将开口泡要满足的三个不独立的边界条件简化为两个独立的边界条件,给出高斯测地曲率kg=-2,边界条件2可满足,然后由边界条件1得到确定膜泡边界的几何方程.进而讨论了由欧阳双凹盘解可构造的开口泡的各种可能形状,得到了三类管型拓扑解,它们是外凸管形解、类环管形解、类悬链面管形解.     

Considering Backward Effect in Coupled Map Car-Following Model

Based on the pioneer work of Konishi et al., a new control method is proposed to suppress the traffic congestion in the coupled map （CM） car-following model under open boundary condition. The influence of the following car to the system has been considered. Our method and that presented by Konishi et al. [Phys. Rev. E 60 （1999） 4000] are compared. Although both the methods could suppress the traffic jam, the simulation results show that the temporal behavior obtained by ours is better than that proposed by the Konishi＇s et al. The simulation results are consistent with the theoretical analysis.     

Reconnection Rate in Collisionless Magnetic Reconnection under Open Boundary Conditions

Collisionless magnetic reconnection is studied by using two-dimensional Darwin particle-in-cell simulations with different types of open boundary conditions. The simulation results indicate that reeonneetion rates are strongly dependent on the imposed boundary conditions of the magnetic field Bx in the inward side. Under the zerogradient Bx boundary condition, the reconnection rate quickly decreases after reaching its maximum and no steady-state is found. Under both electromagnetic and magnetosonie boundary conditions, the system can reach a quasi-steady state. However, the reconnection rate Er ≈ 0.08 under the electromagnetic boundary condition is weaker than Er ≈ 0.13 under the magnetosonic boundary condition.     

阴极透镜层流电子枪调制特性

 通过求解第一类边界条件的拉普拉斯方程,获得了典型的三电极阴极透镜中轴上电位的解析表达式。以此为基础,分析了阴极透镜各几何参数及电位参数对其聚焦性能的影响,得知通过增大调制极电位或其孔径、增加调制极与加速极的间距或缩小调制极与阴极的间距的方法,可以保证在改善初始粒子时间、空间弥散特性的基础上,相对减小轴向电场的非均匀性以减弱其会聚电场强度,从而使带电粒子束在阴极透镜区域中不能形成交叠点,达到构成其中电子运动具有层流性质的阴极透镜层流电子枪的工程应用目的。另外也获得了采用厚度较小的调制极有助于整个电子光学系统性能优化的结论。     

多孔格栅均匀化模型平压仿真分析

为了研究均匀化方法在一种多孔格栅结构中的应用,从格栅单胞尺度入手,建立了一种适用于有限元仿真分析的三维周期性边界条件.以ABAQUS作为分析平台,对周期性边界条件下的格栅单胞模型进行了平压仿真分析,并将仿真结果与文献实验结果对比,验证了该边界条件的可靠性.利用均匀化理论建立了格栅单胞力学平衡方程,得到了格栅均匀化模型....     

三阶偏微分方程的振动结果

本文建立了一类三阶非齐次偏微分方程的一切解振动的若干充分条件,同时也给出了实际应用例子.     

抽象函数性质之辨

自高考题中出现抽象函数以来,利用抽象函数的性质解题的内容也大量出现在刊物和资料上,其中有不少好题,但也有些题在对一类具体函数的共同性质的抽象中,由于对具体函数的性质的“增、失”上有模糊认识,造成了编题或解题中的失误．下面仅举几个例子加以辨析：     

抽象函数不等式问题的探究策略

纵观近几年的高考试题,抽象函数不等式问题一直倍受命题者的关注．这类问题往往具有抽象性、综合性、技巧性、隐蔽性等特点,加之解决这类问题时,要求考生基础知识扎实,