Smooth and Nonsmooth Lipschitz Controls for a Class of Vector Differential Equations

This paper is devoted to the study of a class of control problems associated to a nonlinear second-order vector differential equation with pointwise state constraints. The control is realized via a function of the state. We extend the results of Akkouchi, Bounabat, and Goebel to vector differential equations and furthermore consider the more general case. Under proper conditions, we prove the existence of optimal controls in the class of Lipschitz functions and obtain an optimality condition which looks somehow like the Pontryagin maximum principle for a smooth optimal control function. For a nonsmooth optimal control function, we derive a suboptimality condition by means of the Ekeland variational principle.Communicated by M. J. BalasThis work was supported by 985 Project of Jilin University. The author thanks Professor Yong Li for valuable suggestions. He also thanks Professor M. J. Balas and the anonymous referees for their comments.     

有机薄膜电致发光器件载流子注入和传输性质的研究

制备了不同电极、不同厚度、以8-羟基喹啉铝螯合物(Alq3)为发光层的有机薄膜电致发光(TFEL)器件。分析了它们的电流密度-电压关系。不同阳极器件的电流变化很大,而改变阴极时电流密度的变化较小,说明电流以空穴为主。根据不同阴极器件的电致发光效率的比较,说明电子是决定器件电致发光效率的少数载流子。从不同厚度的器件的结果讨论了载流子的传输性质,认为在ITO/Alq3/Al器件中的电流符合陷阱限制的空间电荷电流.     

Surface roughness effects on stress determination by the x-ray diffraction method

Experimental Techniques -     

多环架光电稳定系统及分析

提出一种多环架高精度光电稳定系统方案。通过对其进行运动学分析，并结合伺服控制原理，证明该方案优于常规的二环架光电稳定系统。     

不等面积设施布局 的收敛 算法

采用单变量搜索在大范围移动设施以寻找最佳布局位置是不等面积矩形设施自动布局的一种算法‘但它的布局结果依赖于各设施的初始排列以及它们的移动次序.为了便于对原有布局进行迭代改进，本文使用.控制收敛”方法.它通过用放大设施数倍的包络块来代替原来的设施进行初始布局，并在每次优化循环后缩小包络块大小来为下一次优化循环产生移动空余空间，通过循环优化使设施的大小逐渐缩小到实际大小而终止.实例调试结果表明了该方法是有效的.     

焦散线法及其与应力“解冻”相结合的应用

详细地阐述了焦散线法原理，对焦散线的形成作了说明，简述了焦散线法在平面问题中的应用，结合笔者研究工作介绍了将焦散线法拓广应用于三维问题的关键技术和实例。     

Study of the structural relaxation and crystallization in amorphous Fe80P20 alloy by mössbauer effect

The structural relaxation and crystallization of amorphous Fe₈₀P₂₀ alloys have been investigated by Mössbauer spectroscopy. The result indicates that the process of the crystallization of Fe₈₀P₂₀ makes slow progress and it was occur from outside into inside. The amorphous alloys may be classified into six different stages from amorphous to crystalline state during annealing.     

非均匀Reissner板弯曲的精确元法

本文在阶梯折算法和精确解析法的基础上,提出构造有限元的新方法——精确元法.该方法不用变分原理,可适用于任意变系数正定和非正定偏微分方程.利用该方法,得到Reissuer板弯曲的一个非协调单元,它具有十五个自由度.由于节点位移参数仅含有挠度和转角,因此处理任意边界条件非常容易.文中给出证明,位移和内力均收敛于精确解.由精确元法所得到的单元不仅能用于厚板,也可用于薄板.文末给出四个算例.算例表明,利用本文的方法,可获得满意的结果,并有较高的数值精度.