Singular optimal control problems: On the order of a singular arc

The higher-order tests for optimality of singular arcs in optimal control problems, as well as the characterization of the continuity and smoothness properties of the optimal control at points, called junctions, joining nonsingular and singular arcs of the control, depend upon the orders of the arcs involved. To data, definitions of order have been rigorously given only for terminal unconstrained control problems or by means of a normality assumption in the order cases. We give here a new definition of the local order of a singular arc which unifies those already given in the literature. One advantage of the proposed definition is that, unlike the previous ones, it remains valid even when there are terminal constraints. One example will illustrate the fact that such a basic concept is essential to solve the very difficult synthesis problem as soon as the dimension of the state space is greater than two.     

OFDM系统中信道有效阶数的估计

信道估计是无线通信的关键技术之一，知道信道长度可以提高信道估计的精度．本文针对基于OFDM调制技术的无线通信系统中LS信道估计算法时域结果的构成特点，结合无线信道冲激响应在时域为有限冲激响应的特点，提出对LS信道估计算法的时域结果进行能量检测，并进行逆向搜索以获得信道有效阶数估计的算法．同时从检测概率角度给出了检测门限．最后给出了计算机仿真结果．理论分析和计算机仿真表明此算法能够很好地得到信道有效阶数估计结果．     

直孔电站混凝土拌和系统成功经验浅谈

介绍了拉萨直孔电站采用HLS60型连体式拌和楼系统的成功经验，具体包括以下几方面：(1)生产管理自动控制系统的监控；(2)机械设备的监控；(3)拌和中对质量的控制；(4)停机过程；(5)检修维护及日常保养。     

Edge Stress Intensity Functions in Polyhedral Domains and their Extraction by a Quasidual Function Method

The solution to elastic isotropic problems in three-dimensional (3-D) polyhedral domains in the vicinity of an edge is provided in an explicit form. It involves a family of eigen-functions with their shadows, and the associated edge stress intensity functions (ESIFs), which are functions along the edges. Utilizing the explicit structure of the solution in the vicinity of the edge we use the quasidual function method, recently presented in [Omer et al. (2004). International Journal of Fracture 129:97–130] for scalar elliptic problems and in [Costabel et al. (2004). SIAM Journal of Mathematical Analysis 35(5), 1177–1202] in a general theoretical framework, for the extraction of ESIFs. This method provides a polynomial approximation of the ESIF along the edge whose order is adaptively increased so to approximate the exact ESIF. It is implemented as a post-solution operation in conjunction with the p-version finite element method. Numerical examples are provided in which we extract ESIFs associated with traction free or homogeneous Dirichlet boundary conditions in 3-D cracked domains or 3-D V-Notched domains. These demonstrate the efficiency, robustness and high accuracy of the proposed quasi-dual function method.     

浅谈俄语词序的交际功能

从俄语词序的交际功能出发，阐明了俄语是曲折的，其词序既是自由的，又是固定的。在不同的语境和上下文的制约下，具有不同的交际功能，服务于不同的交际目的，使句子具有特殊的表达效果，能给人以深刻的印象。     

运用遥感及非地震物探数据划分盆地三级构造单元

中国尚有数百个盆地处于早期油气勘探阶段，盆地早期评价方法研究意义重大。遥感及非地震物探数据各有特长，在盆地早期评价中可发挥重要作用。提出基于遥感及非地震物探数据的盆地三级构造单元平面与剖面立体综合解释模式。以百色盆地为试验区，阐述了该模式的具体工作步骤和应用效果。该模式的核心是两种数据的综合分析与立体结合，其关键是利用两种不同层次数据的综合分析来确定断层的性质。该方法应用效果明显     

InGaP/GaAs外延材料合金有序度的表征

对InGaP/GaAs外延材料合金有序度表征方法进行了综述，指出从结构X-Ray）光学性能摘要（透射电子显微镜，、（光、电学性能三方面度量InGaP/GaAs材料的有序度。     

榴弹射表编拟中符合方法的研究

选择降阶的刚体弹道模型作为编表模型，通过各参数所形成的射程与偏流的敏感因子的比较以及各符合方案的对比，提出以零阻力系数和相对静力臂系数为符合系数，以射程和偏流为符合对象，进行综合符合的方法，通过在不同射角下符合时，射表主要误差源所造成的射表误差的论证，确定出了合理的符合射角选择区域，并提出了以４５°作为符合射角的符合方案。     

基于DSP的振动信号阶比与时域同步平均分析

本文介绍了阶次这一特征分量在机械故障诊断中的应用，以及其原理和各种具体实现方法。而时域同步平均可以有效衰减与回转频率无关的干扰，提取与工作状态直接相关的周期信号。同时，时域同步平均的实现方法与阶比分析也有相似之处，所以本文也对其作了介绍。在比较几种传统方法后，提出了采用高速数字信号处理器DSP电路和插值算法来进行振动信号的阶比分析和时域同步平均处理。克服了基于锁相环电路采样方法跟踪精度低，速度慢和使用不便的缺点。