Multimaterial design of physically nonlinear structures

A theoretical consideration of optimization problems for physically nonlinear hyperelastic structures is carried out. The structures are subjected to a single static “dead” loading and a multimaterial design approach is analysed. Structural materials are assumed to be isotropic, with stress-strain relations being weakly concave. The problems considered are mass minimization with prescribed structural stiffness, stiffness maximization with prescribed structural mass, and mass minimization with constrained stresses. Optimality conditions for the problems are analysed. Generalizations of Maxwell’s and Michell’s theorems for the considered structures are proved. Some regularities inherent in the third problem are analysed using the analytical example of a three-rod physically nonlinear truss made of two materials. An algorithm for compliance decreasing in the case of prescribed structural mass is proposed. The monotonicity property of the algorithm is proved. Numerical examples (bi-material beam and airframe) are presented and corresponding results are analysed on a basis of the theoretical approaches developed. Received November 3, 1999     

三点式超声测距测角装置

论述了利用三只超声换能器测量距离和角度的原理,给出了硬件电路原理图和软件流程图,分析了引起测量误差的主要原因,提出了减小系统误差和随机误差的措施。     

Microsoft LRN及其e—Learning实现

简单介绍了IMS规范和e-Learming概念，详细剖析了MicrosoftLRN中e-Learning的实现思想及其实现技术方法，以应用实例分析了Microsoft LRN的实用价值。     

嵌入式Linux在车载导航系统中的应用

描述了将Linux移植到基于MOTOROLA MX1处理器的目标板上的方法和过程。介绍了导航系统的原理,分析了嵌入式Linux操作系统及文件系统,并结合导航系统介绍了嵌入式Linux的具体开发步骤,着重介绍Linux内核的移植。结果证明该方法是可行的。移植后的Linux在目标板中运行良好。     

多UUV协作系统的研究现状与发展

介绍了多UUV（Unmanned Underwater Vehicle）协作系统的结构和特点，分析了其未来应用前景，并对国外多UUV系统的应用现状进行了综述．在此基础上，着重分析了系统涉及的导航、通信、控制和能源等技术的研究现状并展望了其未来的发展方向．     

环形激光陀螺信号分析与处理

我们对环形激光陀螺输出信号进行了时频分析,采用Allan方差法对陀螺信号进行了分析与计算,应用混合滤波技术对陀螺信号进行了处理,并对滤波前后的陀螺测试数据进行了对比分析.Allan方差法分析结果表明,该滤波技术能有效提高激光陀螺的精度.     

On numerical error in the finite element method

Various sources of errors, physical and numerical, in the finite element method are analysed. A new type of iterative improvement is introduced where the residual is calculated in single precision. The iteration scheme is analysed with respect to round-off errors and found to give significant improvement over existing direct approaches.     

偏差比例双交叉限幅控制在生产中应用

阐述了常规双交叉限幅控制在燃烧控制中的优点,分析了其在实际生产应用中所存在的问题,针对所存在问题提出了"偏差比例双交叉限幅控制"控制策略,同时切实分析"偏差比例双交叉限幅控制"的控制思路,并提供详尽的控制原理图。生产实际表明,带钢退火温度可控制在±5℃以内,温度控制均匀,延长了退火炉的使用寿命,降低了环境污染。由于控制系统调节能力的加强,过渡卷的使用降低了3％,提高了退火炉的处理能力和产品的成材率。     

矿山产能分配的变量模糊线性规划模型

针对矿山资源开采过程中产能不确定的分配问题,引入了模糊结构元素理论。将产能用结构元表示,并利用结构元加权序将模糊数比较转化为单调函数比较,将含有模糊变量的线性规划问题等价转化为经典线性规划问题。以某矿山为例,建立矿山产能分配的变量模糊线性规划模型,并进行求解。结果表明：实现了将实际问题中的模糊事件进行精确表达,原问题的求解更简便。得到矿山产能取得最大可能利润时的可能分配。应用结构元加权序求解的线性规划模型优于结构元元序的。     

Self-tuning control by model unfalsification (Part II)

The transient problem in self-tuning control is further analysed in a non-stochastic framework based on model unfalsification and solutions are proposed. It is not assumed that the noise bounds or norm bounds on the unmodelled dynamics were known a priori. Depending on the transient requirements on output bound, tracking performance and length of tuning period, three cases are analysed. Simulations show the practical potential of the tuning methods presented.