STABILIZATION OF A CLASS OF NONLINEAR NON‐MINIMUM PHASE SYSTEMS

This paper tackles the problem of stabilization of a class of non‐minimum phase nonlinear systems which have zero dynamics with an eigenvalue zero of multiplicity 2. By adding some new terms, called cross terms, we are able to generalize the concept of the Lyapunov function with a homogeneous derivative along the trajectory, which was introduced in [4], to produce a suitable Lyapunov function. The Lyapunov function assures that the stability of an approximate system, which consists of some lower order terms of a nonlinear system with an eigenvalue zero of multiplicity 2, implies the stability of the whole system. Applying these to non‐minimum phase zero dynamics of nonlinear systems with such a center, a sufficient condition and a design method of state feedback control are obtained for stabilizing the systems.     

具有多项式型非线性项的大规模随机非线性系统的分散输出反馈镇定

基于齐次占优方法研究 具有多项式型非线性项的大规模随机非线性系统的分散输出反馈镇定问题. 本文的主要贡献在于利用高增益齐次占优方法来解决大规模随机非线性系统的分散控制问题. 这种方法能彻底地去掉传统结果中所要求的线性增长条件, 不仅推广了以前的结果还得到了一些新的结果. 仿真验证了输出反馈控制器的有效性.     

A subgrid stabilization finite element method for incompressible magnetohydrodynamics

This paper studies a numerical scheme for approximating solutions of incompressible magnetohydrodynamic (MHD) equations that uses eddy viscosity stabilization only on the small scales of the fluid flow. This stabilization scheme for MHD equations uses a Galerkin finite element spatial discretization with Scott-Vogelius mixed finite elements and semi-implicit backward Euler temporal discretization. We prove its unconditional stability and prove how the coarse mesh can be chosen so that optimal convergence can be achieved. We also provide numerical experiments to confirm the theory and demonstrate the effectiveness of the scheme on a test problem for MHD channel flow.     

比例时滞线性系统的反馈镇定

研究了比例时滞线性系统的反馈镇定问题．利用标准反馈控制与时滞反馈控制实现系统不稳定平衡点的镇定．构造合适的李亚普诺夫泛函，得出了闭环系统稳定的几个充分条件．通过实例说明了方法的有效性．     

基于CompactPCI总线数字隔离I/O模块的实现

本文介绍了基于CompactPCI总线数字隔离I/O(Input/Output)模块的实现。通过硬件和驱动的设计,该模块可以实现数字信号传输和隔离的作用,在内场测试系统中起到了实际的作用。     

现代高校网络解决方案

本文根据高校校园网建设的需求分析,探讨了针对校园网建设所涉及的重要问题,即稳定可靠、管理、安全性、升级等几个重点方面并简要的介绍了其解决方案.     

IEEE802.16接收机检测模块的FPGA实现

提出了一种采用现场可编程门阵列器件FPGA实现802.16接收端MIMO(多输入多输出)2×2检测的方案。在C语言平台对基于并行干扰消除的最小均方误差的算法进行研究和仿真后,使用Verilog硬件描述语言对MIMO检测各模块分别设计;均通过了综合和验证;这样本文提出了对系统起重要作用的接收端的MIMO检测芯片的实现方法。     

软岩采场边界失稳原因分析及应对措施

从放矿过程、爆破震动、上覆岩等方面对有底部结构空场法侧壁失稳的原因进行了深入研究，提高了对边界失稳机理的认识；同时，在对大量采场边界失稳观测和分析的基础上，提出了坍塌角经验公式，并以此为依据提出对策。通过生产实践证明，采取的措施行之有效，能避免边界失稳带来的影响，使采切工程和落矿中深孔的布置更具合理性。     

Locking and hourglass phenomena in an element‐free Galerkin context: the B‐bar method with stabilization and an enhanced strain method

The meshless methods, namely the element‐free Galerkin method (EFGM), when they first appeared claimed that volumetric locking and hourglass were avoided. This was not the case and both phenomena occur in the EFGM. In the context of the finite element method (FEM) these phenomena were widely studied. In this work, forms of avoiding the locking phenomenon will be presented; a formulation based on the enhanced strain method will be introduced in the EFGM and the B‐bar method will be implemented under the scope of the EFGM. Secondly, to render this method more robust, a stabilization technique will be implemented avoiding hourglass. Several examples are solved to probe the efficiency of these techniques. Copyright © 2006 John Wiley & Sons, Ltd.     

济钢烧结节能降耗与工艺优化技术应用

结合济钢烧结厂的生产实际，从技术、管理及操作等各个方面，致力于多项节能技术的开发，使烧结生产的各种能源介质单耗明显下降。