On non-explosion for the solution of a stochastic differential equation

In the present work we give general sufficient conditions in terms of Lyapunov functions which ensure existence of a weak solution for a stochastic differential equation for which conditions of existence hold in every bounded region.     

互易定理适用的充要条件

给出互易定理适用于无独立源线性定常网络的充分必要条件。     

在—集中载荷作用下斜边自由的三角形板弯曲

本文应用功的互等定理研究了在—集中载荷作用下斜边自由两边固定的三角形板弯曲问题.该法简单、通用.     

弹性矩形薄板受迫振动的功的互等定理法(Ⅲ)—悬臂矩形板

本文应用功的互等定理法给出了在均布谐载和在任意点受集中谐载作用下悬臂矩形板受迫振动的稳态解,并给出了有关弯矩和挠度幅值的图表.     

考虑互惠公平的创新顾客激励契约研究

基于公平偏好理论的互惠公平,从创新顾客的互惠偏好程度、激励契约类型与激励效果的关系入手,构建创新顾客参与企业创新活动的激励模型。通过模型求解和分析,探讨激励契约的外部性和互惠关系对于激励效果的影响;此外,进一步分析如何联合经济激励和心理激励,降低企业获得创新顾客高努力投入的成本;最后,通过仿真实验,验证模型分析结果。研究发现:当创新顾客之间出现互惠关系时,最优激励契约取决于创新顾客心理偏好与风险态度之间的相互作用:当创新顾客的风险规避程度较低时,最优激励契约为相对绩效契约;当创新顾客的风险规避程度较高时,最优激励契约为团队报酬契约。     

基于模糊互补判断矩阵的对数最小一乘法及算法程序设计

利用正互反判断矩阵与模糊互补判断矩阵的转换关系,探讨模糊互补判断矩阵的一种排序方法——对数最小一乘法,并给出这种算法的程序设计.     

Contact shape optimization based on the reciprocal variational formulation

The paper deals with a class of optimal shape design problems for elastic bodies unilaterally supported by a rigid foundation. Cost and constraint functionals defining the problem depend on contact stresses, i.e. their control is of primal interest. To this end, the so-called reciprocal variational formulation of contact problems making it possible to approximate directly the contact stresses is used. The existence and approximation results are established. The sensitivity analysis is carried out.     

线载荷积分方程法分析桩顶受任意荷载的弹性斜桩

嵌在各向同性均匀弹性半空间的弹性斜桩顶部,受任意荷载的位移和应力,可分解为在倾斜平面xOz及其法平面yOz内进行分析.将Mindlin力作为基本虚载荷,令集度为未知函数X(t)、Y(t)、Z(t),分别平行于x、y、z轴,的基本载荷沿桩轴t的[0,L]内分布,并在桩顶作用集中力Q_x,Q_y、Z,力偶矩M_y、M_x,根据弹性桩的边界条件,将问题归结为一组Fredholm-Volera型的积分方程.文中给出数值解.计算结果的精度可用功的互等定理来检查.     

Some basic principles for linear coupled dynamic thermopiezoelectricity

According to the basic idea of classical yin-yang complementarity and modern dualcomplementarity, in a simple and unified way some basic principles for linear coupled dynamic thermopiezoelectricity can be established systematically. An important integral relation in terms of convolutions is given, which can be considered as the generalized principle of virtual work in mechanics. Based on this relation, it is possible not only to obtain the principle of virtual work and the reciprocal theorem in linear coupled dynamic thermopiezoelectricity, but also to derive systematically the complementary functionals for eleven-field, nine-field, six-field and three-field simplified Gurtin-type variational principles. Furthermore, with this approach, the intrinsic relationship among various principles can be explained clearly. Project supported by the National Natural Science Foundation of China (Grant No. 19672074) and Research Grand Council of Hong Kong, No.RGC97/98, HKUST 6055/97E.     

The power of in situ pulsed laser deposition synchrotron characterization for the detection of domain formation during growth of Ba0.5Sr0.5TiO3 on MgO

A highly sophisticated pulsed laser deposition (PLD) chamber has recently been installed at the NANO beamline at the synchrotron facility ANKA (Karlsruhe, Germany), which allows for comprehensive studies on the PLD growth process of dielectric, ferroelectric and ferromagnetic thin films in epitaxial oxide heterostructures or even multilayer systems by combining in situ reflective high‐energy diffraction with the in situ synchrotron high‐resolution X‐ray diffraction and surface diffraction methods. The modularity of the in situ PLD chamber offers the opportunity to explore the microstructure of the grown thin films as a function of the substrate temperature, gas pressure, laser fluence and target–substrate separation distance. Ba_0.5Sr_0.5TiO₃ grown on MgO represents the first system that is grown in this in situ PLD chamber and studied by in situ X‐ray reflectivity, in situ two‐dimensional reciprocal space mapping of symmetric X‐ray diffraction and acquisition of time‐resolved diffraction profiles during the ablation process. In situ PLD synchrotron investigation has revealed the occurrence of structural distortion as well as domain formation and misfit dislocation which all depend strongly on the film thickness. The microstructure transformation has been accurately detected with a time resolution of 1 s. The acquisition of two‐dimensional reciprocal space maps during the PLD growth has the advantage of simultaneously monitoring the changes of the crystalline structure as well as the formation of defects. The stability of the morphology during the PLD growth is demonstrated to be remarkably affected by the film thickness. A critical thickness for the domain formation in Ba_0.5Sr_0.5TiO₃ grown on MgO could be determined from the acquisition of time‐resolved diffraction profiles during the PLD growth. A splitting of the diffraction peak into two distinguishable peaks has revealed a morphology change due to modification of the internal strain during growth.