联合使用激波捕获—拟合法求解激波间断的跨声速流场

吸取激波捕获和激波拟合两种方法各自的优点,发展了一种求解有激波的跨声速流场的方法,并对回转叶栅中定常跨声速流场做了计算。计算中,通过捕获法确定初始激波位置,然后经反复修正,拟合出确定的流场通道激波。计算表明,这种方法可自动获得清晰的激波,流场中气流各参数分布合理。这一方法可适用于复杂边界和不同进口M数,计算时间仅比势函数方法多一倍左右。     

常温腐蚀对Al-Si涂层氧化行为的影响

研究了未经 /经常温腐蚀的 DZ1 2 5镍基合金表面 Al-Si涂层的高温氧化行为。结果表明 ,经腐蚀的涂层等温氧化行为发生变化。在初始阶段 ,经腐蚀的试样增重大于未经腐蚀的试样 ,而且经腐蚀的试样的耐高温性能明显下降。氧化皮中主要是 Al2 O3及少量的 Ti O2 .     

用于被动寻的导弹的带末端落角约束的变结构导引律

使被动寻的导弹在较低的平飞弹道情况下，以较小的俯冲过载和最佳攻击姿态精确命中目标；采用带落角约束的变结构导引律，对弹目距离及距离变化率进行估计，克服被动寻的导弹不能测距的约束，同时使切换开关增益随时间自适应变化以减小俯冲过载；利用某型在研被动寻的导弹的气动参数，对此变结构导引律进行了数学仿真，仿真结果表明，在较低的平飞弹道约束条件下及过载要求范围内，该导引律能以期望落角命中静止与机动的坦克目标，对弹目距离变化率及距离的较大估计误差具有较强的鲁棒性。     

斜齿圆柱齿轮正交法参数优化设计

用正交法对斜齿圆柱齿轮传动进行参数优化设计 ,用方差分析法找出对质量影响最显著的因素 ,最后 ,由信噪比作为指标选出最佳参数组合 ,这是一种快速创新开发产品的设计方法。     

连续自由流电泳微重力下分离模式蛋白质的研究

以连续自由流电泳的区带电泳模式分离血红蛋白和细胞色素C，比较了不同缓冲液甘油浓度下的分离效果，确定了最终装载在神舟4号飞船上A3—2型电泳仪的电泳分离条件，通过地面和空间实验，初步探讨了微重力对连续自由流电泳分离的影响，并对电泳的分离产物做了多种检测．     

MATLAB在飞机环境控制系统仿真中的应用

介绍了在MATLAB环境下,对飞机环境控制系统的建模方法,开发了飞机环控系统综合仿真的MATLAB工具箱.简单介绍了所开发的仿真工具箱,并且用此工具箱对某型飞机的环控系统进行了仿真研究,与实验结果的对比表明,所开发的工具箱,具有很高的仿真精度.     

Influence of TiB2 particles on machinability and machining parameter optimization of TiB2/Al MMCs

In situ formed TiB₂ particle reinforced aluminum matrix composites (TiB₂/Al MMCs) have some extraordinary properties which make them be a promising material for high performance aero-engine blade. Due to the influence of TiB₂ particles, the machinability is still a problem which restricts the application of TiB₂/Al MMCs. In order to meet the industrial requirements, the influence of TiB₂ particles on the machinability of TiB₂/Al MMCs was investigated experimentally. Moreover, the optimal machining conditions for this kind of MMCs were investigated in this study. The major conclusions are: (1) the machining force of TiB₂/Al MMCs is bigger than that of non-reinforced alloy and mainly controlled by feed rate; (2) the residual stress of TiB₂/Al MMCs is compressive while that of non-reinforced alloy is nearly neutral; (3) the surface roughness of TiB₂/Al MMCs is smaller than that of non-reinforced alloy under the same cutting speed, but reverse result was observed when the feed rate increased; (4) a multi-objective optimization model for surface roughness and material removal rate (MRR) was established, and a set of optimal parameter combinations of the machining was obtained. The results show a great difference from SiC particle reinforced MMCs and provide a useful guide for a better control of machining process of this material.     

Geometric error analysis of an over-constrained parallel tracking mechanism using the screw theory

This paper deals with geometric error modeling and sensitivity analysis of an overconstrained parallel tracking mechanism. The main contribution is the consideration of overconstrained features that are usually ignored in previous research. The reciprocal property between a motion and a force is applied to tackle this problem in the framework of the screw theory. First of all, a nominal kinematic model of the parallel tracking mechanism is formulated. On this basis, the actual twist of the moving platform is computed through the superposition of the joint twist and geometric errors. The actuation and constrained wrenches of each limb are applied to exclude the joint displacement. After eliminating repeated errors brought by the multiplication of wrenches, a geometric error model of the parallel tracking mechanism is built. Furthermore,two sensitivity indices are defined to select essential geometric errors for future kinematic calibration. Finally, the geometric error model with minimum geometric errors is verified by simulation with SolidWorks software. Two typical poses of the parallel tracking mechanism are selected, and the differences between simulation and calculation results are very small. The results confirm the correctness and accuracy of the geometric error modeling method for over-constrained parallel mechanisms.     

基于人工神经网络的停机坪安全预警研究

停机坪是机场的重要组成部分,停机坪安全是机场安全关注的重点。影响停机坪安全作业的要素有很多,通过对这些要素进行监控和预警,可以减少停机坪的安全隐患,保证机场正常运行。根据济南遥墙机场的主要数据,运用因子分析法对影响停机坪安全的主要因素进行分类,提取公共因子。并运用人工神经网络（ANN）方法,对这些公共因子进行神经网络训练和预测分析,最终得到遥墙机场停机坪的安全情况。     

基于非线性变换的加速度计误差标定与补偿CSCD

为提高三轴加速度计测量精度,分析其误差来源和产生机理,建立了误差模型;根据误差模型和重力场幅值不变特性,推导出非线性观测方程。引入两个未知的参数向量,通过数学变换把非线性观测方程变形为关于新未知参数的线性方程;然后采用批量最小二乘法求出新的未知参数,并根据误差模型参数和新未知参数之间的关系,利用逆解析运算求出对应的零点偏差、灵敏度误差和三轴不正交误差。实验结果表明,加速度计正负误差峰值间距可以减小100倍左右,精度可达10-3m/s2,并具有很好的可重复性。该方法算法效率较高,补偿效果显著。