二维欧拉方程的非结构网格自适应方法

给出提高二维欧拉定常解质量的非结构网格自适应方法。网格的生成采用Ｅｅｌａｕｎｅｙ方法,流场的算法为节点型有限体积法,能量的计算采用Ｖａｎｌｅｅｒ格式,自适应采用网格的增加和删减。对流场特性的探测采用密度物质导数的绝对值。最后计算了Ｎａｃａ００１２翼型的跨音速绕流,结果证明自适应效果很好。     

响应函数虚部对振荡燃烧的影响

本文用一实例简洁、通俗地分析了推进剂响应函数的虚部对火箭发动机振荡燃烧频率的影响.这种影响是计算频率与实际测得频率有偏差的主要因素.     

湍流度和雷诺数对附面层转捩位置的影响

对于层流翼型模型（翼弦长300mm），当湍流度小于0.1％时，对附面层转捩点位置没有明显影响，但其大于0．1％以后则影响明显；而对NACA0024对称翼型（弦长400mm）模型，其表面附面层转捩点位置不受湍流度的影响。对于两个不同尺寸的层流翼型模型（弦长分别为300mm和800mm）而言，当雷诺数大于某一位后转按点位置才受雷诺数的影响，对于NACA0024对称翼型模型，其表面阻面层的转捩点位置也不受雷诺数影响，且转捩点位置与变湍流度情况下在同一位置上。     

Reliability and safety analysis of redundant vehicle management computer system

Redundant techniques are widely adopted in vehicle management computer （VMC） to ensure that VMC has high reliability and safety. At the same time, it makes VMC have special characteristics, e.g., failure correlation, event simultaneity, and failure self-recovery. Accordingly, the reliability and safety analysis to redundant VMC system （RVMCS） becomes more difficult. Aimed at the difficulties in RVMCS reliability modeling, this paper adopts generalized stochastic Petri nets to establish the reliability and safety models of RVMCS. Then this paper analyzes RVMCS oper- ating states and potential threats to flight control system. It is verified by simulation that the reli- ability of VMC is not the product of hardware reliability and software reliability, and the interactions between hardware and software faults can reduce the real reliability of VMC obviously. Furthermore, the failure undetected states and false alarming states inevitably exist in RVMCS due to the influences of limited fault monitoring coverage and false alarming probability of fault mon- itoring devices （FMD）. RVMCS operating in some failure undetected states will produce fatal threats to the safety of flight control system. RVMCS operating in some false alarming states will reduce utility of RVMCS obviously. The results abstracted in this paper can guide reliable VMC and efficient FMD designs. The methods adopted in this paper can also be used to analyze other intelligent systems＇ reliability.     

Export control regime for space items in China: Opportunities and challenges in the new era

Export control system is vital to effective control of sensitive items and technologies and thus an appropriate system is indispensable to the realization of the goal of non-proliferation. The progress so far shows that China has made great efforts in constructing a domestic regime for export controls. Nevertheless, it has also been recognized that the mere existence of a domestic regime is not sufficient and that the realization of export control should be complemented with effective and efficient enforcement. The paper examines the effectiveness of the current export control regime in China and explores means to strengthen the current regime to dispel the concerns from other nations. The paper concludes that China has been committed to export controls in sensitive space items in the past years; yet further improvements could be made to better serve China's national interests and its commitments under international nonproliferation export control regimes.     

复杂电磁环境下雷达侦察系统的干扰抑制方法

研究了复杂电磁环境下雷达侦察系统的干扰抑制技术,分析了某雷达侦察系统采用的几种抗干扰方式,用试验数据论证干扰抑制方法的可行性,并指出其优势和劣势。最后展望了该领域的趋势和前景。     

复合材料等效模型的适用性分析

建立了复合材料三维等效弹性常数模型,分别以对称铺层的三维实体结构、对称和不对称铺层层板结构为研究对象,通过与分层模型计算结果的比较,分析了等效模型的适用性,得出了一些有意义的结论.     

多连杆检测系统的误差补偿与试验

介绍了一种多连杆检测系统，对其误差进行了分析，提出了一种误差补偿的方法－－多元样条函数拟合播值法，试验表明方案可行，可基本消除系统误差。