轮盘偏心孔低循环疲劳寿命预测法

本文在系统的试验研究基础上提出了应用光滑圆棒试样的低循环疲劳断裂寿命统计数据来精确地预测轮盘偏心孔的低循环疲劳起始中值寿命和可靠性寿命(存活率p=99.9％)的方法。研究表明,对近似于单轴应力状态的轮盘偏心孔来说,其起始寿命一般只与危险点上的最大应变历程有关,而与应变梯度关系不大。研究还表明,中值寿命通常只与钢的化学成份和热处理种类有关;而可靠性寿命则与许多因素有关。     

Filtering of discontinuous processes arising in marine integratednavigation systems

A refined stochastic model for the errors of the Loran-C radio navigation aid is described, and it is shown how this model can be used to improve the performance of integrated navigation systems. In addition to the usual propagation errors, Loran-C time of arrival measurements are occasionally plagued with sudden intermittent errors of a particular magnitude and caused by receiver cycle selection errors. These result in sudden large jumps in the calculated position solution. The Loran-C error has been modeled as the sum of a diffusion process, representing the normal propagating errors, and a pure jump process of Poisson type, representing the cycle selection errors. A simple integrated navigation system is then described, based on the Loran-C model and the standard dead reckoning (heading and speed) system model. Assuming that the observed process is governed by a linear stochastic difference equation, a recursive linear unbiased minimum variance filter is developed, from which the Loran-C and dead reckoning errors, and hence position and velocity, can be estimated     

以科研为关键加快向研究型大学转变的步伐--庆祝南京航空航天大学建校50周年

首先回顾了建校50年来的科研工作,着重介绍了“七五”－“九五”期间我校承担国防型号任务,加强基础研究,跟踪高新技术等方面取得的成绩;总结了取得科研业绩的经验和体会;队伍是根本,基地是关键,团队是基础;并提出为实现向研究型大学转变的战略目标,必须进一步巩固完善科研管理体制和机制,加快向研究型大学转变的步伐。     

典型几何和流动参数对高超声速进气道性能的影响

用N-S方程模拟了一系列典型二元高超声速进气道内压缩通道及隔离段模型,模拟发现内压缩通道及隔离段增压比、温升比和总压恢复系数等性能参数主要受面积收缩比、内压缩通道收缩角、隔离段长高比等几何参数以及内压缩通道进口马赫数、密度、附面层厚度等流动参数的影响。内收缩比和内收缩通道收缩角的增大都会使压缩增强;隔离段内沿程平均温升比、马赫数和总压恢复系数曲线则均接近平行直线。内压缩通道进口马赫数的增大也会使压缩增强,但较小的进口马赫数可能引起分离,进而增大增压比;而进口密度增大使附面层变薄,对气流的压缩减弱;进口附面层厚度对沿程平均温升比、增压比以及马赫数的影响近似线性。     

大型转动机械碰摩故障分析的声发射检测系统

汽轮发电机、空气压缩机等采用油膜支撑的大型转动机械,由于安装或运行中的原因,在转子旋转过程中,可能和器壁发生轻微的摩擦和碰击,简称碰摩.声发射技术在碰摩发生特别是故障早期诊断上有优越性.本系统的特点是没有沿用传统的计数、幅度、能量和持续时间等声发射特性参数,而是在声发射包络信号的频率分析中进行特征提取.声发射发生的过程分析和现场试验都表明这种方法对碰摩检测很敏感,在碰摩发生的起始阶段,包络谱中与转速同步的周期性分量显著增加.根据这种新的设计思想自行研制了BUAA碰摩声发射检测仪并对此作了介绍.     

微重力场中对流—辐射—传质系统的地面模拟技术

研究了微重力条件下对流－辐射－传质稳态系统的地面相似模拟技术，进一步发 温度－材料综合保护技术。通过采取补偿热流，调整壁面热流密度分布的方法，保持了原型与尺寸适当缩小后的模型的Ｎｕ数，Ｓｈ数，材料，温度，湿度不变，从而实现模型与原型流动，换热和传质相似。     

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．     

多机并联火箭羽流流场及其底部热环境分析

For the problem that the plume flow field structure of a multi engine parallel rocket is complicated and the bottom thermal environment is extremely harsh, which may cause the failure of the engine structural components, the plume flow field and thermal environment at different altitudes are studied through numerical simulation. The result is compared with the measured results in flight which shows that when the rocket is flying at a low altitude, the plume of the engines do not interfere with each other. As the flight altitude increases, the plumes gradually expand and begin to interfere with each other, and finally there is an obvious backflow at the bottom of the rocket. The maximum heat flux at the moment of take off is basically the same as the measured value in flight. Before the backflow occurs, the heat flux mainly consists of radiant heat, the convective heat flow increases as the flight altitude grows, but it is also much smaller than the peak heat flow at takeoff. The result has certain guiding significance for the optimal design of engine structure thermal protection.     

试飞员能力模型研究

在飞行器研制和人类飞行探索中,试飞员的能力至关重要。针对以往对试飞员能力的评价基本停留在"客观、正确、诚信、能力以及尊重他人"等主观、感性层面,分析了试飞员在飞行器研制试验与鉴定中的作用和任务,给出了试飞员能力模型和"百分制"对试飞员的计划、飞行、评价、报告和建议等基本能力的量化分配。将试飞员能力显性化,有利于试飞员能力的客观评价。