教练机防水设计

通过对飞机结构需要防水部位的阐述,介绍典型结构防水措施,以减少雨水对机体腐蚀,保证飞机在寿命期内的飞行安全.     

高校“双困”毕业生就业难点及就业对策探析

高校"双困"毕业生是就业的特殊群体,要实现"双困"毕业生的充分就业,国家应该从政策上加大扶持力度;高校要有针对性地进行专业技能拓展、心理健康教育和就业指导,提高学生的综合素质能力;"双困"生也应认清就业形势,转变观念,培养自身能力,提升就业竞争力。只有从多方面入手,才能最终达到充分就业的目的。     

基于多反馈延迟技术的雷达杂波模拟器实现

提出采用多反馈延迟的改进卷积处理技术实现雷达杂波模拟,克服了单反馈延迟输出杂波数据周期重复的缺点,使杂波数据在整个I周期内不重复,带来的好处是杂波逼真度高.采用大容量动态存储技术实现数据存储电路的设计,优点是方便快捷地为卷积器提供数据.     

单站无源定位中角度变化率的测量方法研究

讨论了单站无源定位中角度变化率测量的问题.首先简要介绍了差分法、最小二乘拟合法和卡尔曼滤波法的测量原理,其次为了解决滤波模型非线性的影响,提出了一种并行分段处理的卡尔曼滤波方法,最后从数字滤波的角度,通过设计相应的低通滤波器对估计获得的角度变化率数据流进行处理,进一步提高了角度变化率的测量精度.仿真实验对比分析了所述几...     

对地观测旋转扫描辐射计星上定标系统设计

文中介绍了一种对地观测旋转扫描辐射计星上定标系统的设计。该星上定标系统由漫射板、定标灯、黑体、定标均衡装置、漫射板稳定性监测器和太阳入射角监测器等几部分组成。文中描述了该定标系统各部分的作用和功能,并针对提高星上定标精度提了几点建议。     

Numerical investigation on the shock wave transition in a three-dimensional scramjet isolator

The scramjet isolator, which is used to prevent the hypersonic inlet from disturbances that arise from the pressure rise in the scramjet combustor due to the intense turbulent combustion, is one of the most critical components in hypersonic airbreathing propulsion systems. Any engineering error that is possible in the design and manufacturing procedure of the experimental model, and the intense heat release in the scramjet combustor, may cause the performance of the isolator to decrease, leading to its lack of capability in supporting the back pressure. The coupled implicit Reynolds Averaged Navier–Stokes (RANS) equations and the two-equation standard k?ε turbulent model have been employed to numerically simulate the flow fields in a three-dimensional scramjet isolator. The effects of the divergent angle and the back pressure on the shock wave transition and the location of the leading edge of the shock wave train have been estimated and discussed. The obtained results show that the present numerical results are in very good agreement with the available experimental shadow-pictures, and the numerical method is more suitable for capturing the shock wave train and predicting the location of the leading edge of the shock wave train in the scramjet isolator than the present two-dimensional numerical methods. This is due to the small width-to-height ratio of the isolator and the intense three-dimensional flow structures. On increasing the divergent angle of the scramjet isolator, the static pressure along the central symmetrical line of the isolator decreases sharply. This is due to the strong expansion wave generated at the entrance of the isolator, and when the divergent angle of the isolator is sufficiently large, namely 1.5°, a zone of negative pressure is formed just ahead of the leading edge of the shock wave train. At the same time, the shock wave train varies from being oblique to being normal, and then back to oblique. With an increase in the prescribed back pressure at the exit of the scramjet isolator, the leading edge of the shock wave train moves forward towards the entrance of the isolator, and when the back pressure is sufficiently large, unstart conditions in the hypersonic inlet can take place if the shock train reaches the inlet.     

关于圆轴含有弯弯组合的合成弯矩图形状的讨论

本文结合弯弯扭组合变形的例题，利用相关数学知识，证明了圆轴含有弯弯组合的合成弯矩图如果出现曲线，则该曲线必是(上)凹的。     

轻负荷磁头的动态特性

本文采用有限差分法求解非定常修正Ｒｅｙｎｏｌｄｓ方程，采用四阶Ｒｕｎｇｅ－Ｋｕｔｔａ法求发磁头滑块的动力方程组，分别计算出磁头滑块受到冲击或飞越各种障碍物时的动态响应，较全面地反映了磁头滑块的动态时域特性。     

提高飞机使用可用度的途径

飞机的使用可用度是与飞机战备完好性相关的重要参数,本文研究了提高飞机使用可用度的途 径,并提出了飞机可用度最低门限值的概念     

固体火箭发动机概率设计数字模拟

应用数字模拟技术，对固体火箭发动机进行概率设计，并将计算结果与用一次二阶矩可靠度分析方法得到的结果进行比较，结果表明，在应力和强度分布函数及其功能函数相同的情况下，两者结果一致。