计算机水平测试软件、考试管理子系统

本文介绍了基于客户机/服务器（C/S）模式的“计算机水平测试软件”系统的特点，系统构成以及计算机考试子系统的功能。分析了基于浏览器/服务器（B/S）模式和C/S模式的系统开发。     

Multi-objective output-feedback control for microsatellite attitude control: An LMI approach

Mixed H₂/H_∞ output-feedback controller with pole placement constraints against the internal uncertainty of moment-of-inertia variation and space environmental disturbances is proposed for mircosatellite attitude control. The multi-objective controller is designed based on linear model of attitude dynamics. The H_∞ performance takes into account both robustness stability against moments-of-inertia uncertainty and the disturbance rejection aspect. H₂ performance takes into account the LQG aspect which avoids the undesirable wheels’ saturation effect. In addition, the closed-loop poles can be forced into some sector of the stable half-plane to obtain well-damped transient responses. The problem is then reduced to a convex optimization involving linear matrix inequalities (LMIs), so it can be efficiently solved. The simulation results demonstrate that the presented mixed H₂/H_∞ control system is robust stable and optimal in the sense of H₂ norm, and has good steady-state and dynamic performances against the parameter uncertainties and various disturbances for the microsatellite attitude control system.     

边界扫描JTAG控制器设计及实现

从边界扫描测试的概念、工作原理和基本结构入手,分析并设计了边界扫描JTAG控制器,以具体的芯片和指令为例,通过 JTAG 控制器实现了对芯片的边界扫描测试功能,为进一步展开嵌入式边界扫描测试研究工作提供了依据。     

Yield anisotropy and tension/compression asymmetry of a Ni3Al based intermetallic alloy

In order to investigate the yielding behavior of the newly developed Ni 3 Al-based intermetallic alloy IC10, yield stresses have been measured in tension and compression with different orientations. The specimens were cut from a sheet with different angles inclined from the solidification direction. The inclined angles were taken to be 0 , 22.5 , 45 , 67.5 and 90 . All experiments were conducted at room temperature except for orientation 0 , whose deformation temperatures ranged from 298 to 1273 K. Experimental results show that the yield strength of alloy IC10 has the anomalous behavior which has been observed for other Ll 2 -long-range ordered intermetallic alloys, but it is less pronounced. The abnormalities show the following characteristics: (i) the yield strength increases as the temperature is raised below the peak temperature, (ii) yield strength anisotropy, (iii) tension/compression asymmetry. Compared to Ni 3 Al single crystals, the polycrystalline exhibits some different yielding behaviors which may be due to the high volume fraction of c phase.     

SiC/Al2O3纳米复合材料压痕周围残余应力的压谱特性研究

提出了用拉曼显微镜测试 Si C/ Al2 O3纳米复合材料表层 V氏压痕周围残余应力的新方法。试验结果表明 ,其荧光光谱 R曲线峰频率随离压痕中心的距离大小而变化 ,压头施加在材料上的载荷的大小 ,严重影响 R曲线频率的变化。文中假定应力张量横向各向同性 ,并以加压之前材料的荧光光谱作为基值 ,确定压痕周围的残余应力。最后 ,采用等静应力解释并比较了压痕周围残余应力与压痕载荷、离压痕中心距离之间的关系。     

某弹载计算机GJB1188A接口的设计与实现

栽机要求悬挂物必须实现GJB1188A中数据总线(GJB289A)的远程终端(RT)功能,同时实现GJB1188A中任务悬挂物投放允许等接口功能.描述了一种采用TMS320C6713B高速浮点DSP为核心的GJB1188A接口的实现方法,从硬件平台组成、控制逻辑实现、驱动软件结构三个方面来说明GJB289A(RT)功能的实现方法.介绍了任务悬挂物投放允许等接口的一种设计实现方法.从而将以往单一的GJB289A总线接口模块与嵌入式计算机结合在一起.满足了体积和成本上的要求.使嵌入式弹载计算机在GJB1188A接口的前提下实现与机载火控系统的通信、进行同步的数据采集与控制.     

The dark matter halo structure of “fossil” groups candidates

We investigated properties of four isolated giant elliptical galaxies with extended X-ray halo using ASCA data. The derived size of X-ray halo, X-ray luminosity, and gravitational mass of the dark halo are unusually large those of X-ray halo of a single galaxy, but are typical for X-ray halos of groups and poor clusters of galaxies. The measured temperatures and abundances of the X-ray halo gas in these galaxies are also similar to those of the groups and poor clusters. Based on these results we identified these galaxies as ȁc;isolated X-ray overluminous elliptical galaxy” (IOLEG). The radial profiles of dark halo in these objects were derived from X-ray data. It is found that some are similar to those of compact groups while others are the same as those of normal ellipticals. The dark halos of lOLEGs are thus indistinguishable from those of groups (and poor clusters), which appears to be consistent with a widely believed idea that lOLEGs are a product of dynamical evolution of a compact group. However, mass-to-light ratios of IOLEGs (M₂₀₀/L_B  100–1000) are far greater than those of Hickson compact groups M₂₀₀/L_B  40–60). Since it is hard to consider that total optical luminosity of a compact group decreases by an order of magnitude in the course of dynamical evolution, such difference in the observed mass-to-light ratio between IOLEGs and Hickson compact groups strongly suggests that most IOLEGs have not evolved from compact groups which are observed at present.     

K8飞机非加压供氧系统研究

介绍Ｋ８飞机在１３．１ｋｍ高度上使用加压供氧系统的理论计算与试验结果。通过理论计算与试验结论，证明在升限１３．１ｋｍ高度上配备非加压供氧系统是完全可行的。     

基于EBE策略求解流场问题的有限元方程解法研究

本文首先阐述了用有限元法求解流场问题的基于单元接单元（EBE）技术的并行双共轭梯度法（Bi-CGSTAB)。然后引入网格分维概念，并基于网格分维分析和比较了直接法等三种算法的存储量和操作数。最后在国家性能计算中心（成都）的曙光2000并行系统上，采用MPI消息传递实现了此种算法，计算了定常三维空穴流，取了较好的加速比。得到如下结论：EBE迭代法不必生成和存储总刚矩阵，在很大程度上节省了内存，并且它具有良好的并行性，所以EBE的迭代法能有效提高求解流场问题的规模和速度。     

一组新的遥控指令错误概率计算公式的推导

在文 [1]研究的基础上 ,指出遥控指令的误指令概率和漏指令概率不相互独立。并基于这一论断 ,推导出一组新的误指令和漏指令概率的计算公式。