并行求解约束优化问题的QP-free型算法

针对约束块可分的最优化问题,引入序列线性方程组方法和有效集策略,提出了一个求解约束块可分优化问题的QP-free型并行变量分配（PVD）算法.算法中用三个系数具有对称结构的线性方程组来代替PVD算法中的二次规划问题以求解线搜索方向,避免了约束不相容,减小了计算量.并且算法不要求约束是凸的.最后证明了QP-free型PVD算法的全局收敛性.     

Macro‐hybrid mixed variational two‐phase flow through fractured porous media

Macro‐hybrid mixed variational models of two‐phase flow, through fractured porous media, are analyzed at the mesoscopic and macroscopic levels. The mesoscopic models are treated in terms of nonoverlapping domain decompositions, in such a manner that the porous rock matrix system and the fracture network interact across rock–rock, rock–fracture, and fracture–fracture interfaces, with flux transmission conditions dualized. Alternatively, the models are scaled to a macroscopic level via an asymptotic process, where the width of the fractures tends to zero, and the fracture network turns out to be an interface system of one less spatial dimension, with variable high permeability. The two‐phase flow is characterized by a fractional flow dual mixed variational model. Augmented two‐field and three‐field variational reformulations are presented for regularization, internal approximations, and macro‐hybrid mixed finite element implementation. Also abstract proximal‐point penalty‐duality algorithms are derived and analyzed for parallel computing. Copyright © 2016 John Wiley & Sons, Ltd.     

Schur complement‐based domain decomposition preconditioners with low‐rank corrections

This paper introduces a robust preconditioner for general sparse matrices based on low‐rank approximations of the Schur complement in a Domain Decomposition framework. In this ‘Schur Low Rank’ preconditioning approach, the coefficient matrix is first decoupled by a graph partitioner, and then a low‐rank correction is exploited to compute an approximate inverse of the Schur complement associated with the interface unknowns. The method avoids explicit formation of the Schur complement. We show the feasibility of this strategy for a model problem and conduct a detailed spectral analysis for the relation between the low‐rank correction and the quality of the preconditioner. We first introduce the SLR preconditioner for symmetric positive definite matrices and symmetric indefinite matrices if the interface matrices are symmetric positive definite. Extensions to general symmetric indefinite matrices as well as to nonsymmetric matrices are also discussed. Numerical experiments on general matrices illustrate the robustness and efficiency of the proposed approach. Copyright © 2016 John Wiley & Sons, Ltd.     

Extensions of the Fill–Fishkind formula and the infimum – parallel sum relation

Recently, in (Arias ML, Corach G, Maestripieri A. Range additivity, shorted operator and the Sherman–Morrison–Woodburry formula, Linear Algebra Appl. 2015;467), authors gave a generalization of a formula by Fill and Fishkind, regarding the Moore–Penrose inverse of the sum of two matrices, in the setting of arbitrary Hilbert spaces. We consider this formula under some weaker assumptions and derive certain conclusions generalizing the mentioned result. We also extend a formula connecting the infimum of two orthogonal projections and their parallel sum to a formula connecting the star-infimum and the parallel sum of operators which need not be positive, using the concept of parallel sum that was introduced in (Antezana J, Corach G, Stojanoff D. Bilateral shorted operators and parallel sums. Linear Algebra Appl. 2006;414).     

基于protel DXP 2004的RLC电路仿真

用protel DXP 2004软件对RLC电路的暂态过程进行仿真实验分析,主要介绍了仿真电路的创建,并结合电路理论仿真了电路在欠阻尼、临界阻尼和过阻尼三种阻尼状态下的暂态过程。     

迈克耳孙干涉仪条纹计数器的研制

设计了电路简单、可自动识别条纹移动方向的迈克耳孙干涉仪条纹计数器。该计数器仅用9个常见的分立元件即实现了对光信号的采集、放大、滤波、整形的功能,并有效地去除了计数过程中的干扰因素。输出信号经条纹移动方向识别电路后,送入可逆计数器能自动进行相应的加计数或减计数并显示。     

基于平行玻璃板的半导体激光器阵列光束整形

为得到质量均衡的大功率激光束,分别以条形和面阵半导体激光器为模型,基于平行玻璃板对光束的偏移作用,对准直后激光束进行分割和重排,并在Zemax软件中进行了仿真。条形半导体激光器初始发散角为40和10,整形前已准直光束快慢轴方向的光参数积分别为0.455 2 mmmrad和20.484 mmmrad,光束质量相差较大,整形后快慢轴方向光参数积分别为2.731 2 mmmrad和3.414 0 mmmrad,实现了快慢轴方向光束质量均衡。利用平行玻璃板消除面阵半导体激光器中存在的发光死区,整形后快慢轴方向光参数积分别为7.002 mmmrad和10.242 mmmrad ,整形系统耦合效率为90.13%。     

一种求解三维热辐射输运方程的整体预处理迭代方法及并行计算

为三维灰体热辐射输运方程的隐式离散纵标方法发展一个整体预处理迭代方法并研制并行程序.该方法采用组装线性代数方程组策略,同时求出所有离散方向上的辐射强度.借助预处理的Krylov子空间迭代法,避免复杂网格上扫描算法可能遇到的死锁问题,能够提高健壮性和计算效率.空间离散上采用一阶迎风有限体积格式.数值实验测试变形六面体网格...     

基于吸聚一体的低散射传输型透镜设计

通过传输型超表面透镜与电路模拟雷达波吸收器的集成设计,提出了一种兼具透射波前变换与带外雷达散射截面减缩特性的微波复合材料设计方法。透镜采用亚波长分布的周期性单元,由梯度相位补偿对透射波进行调节,进而获得平面波前与球面波前之间的互易变换。并且,使用透镜在波前变换频带以外低频端的反射特征,结合单个有耗层设计,构造了电路模拟吸波器。选用一副缝隙耦合馈电的微带贴片天线单元作为初级馈源天线,观察到复合材料的波前变换特性可在宽频带范围内产生主瓣增益增强效果。与透镜相比,电路模拟吸波器的引入使得复合材料针对TE与TM极化分别可在130.68%与155.11%的频率范围内获得雷达散射截面减缩效果。通过全波模拟和实验测量,验证了辐射增益增强与雷达散射截面减缩效果,表明了复合材料吸聚一体设计的有效性。