一种双管正激磁集成变换器

双管正激磁集成变换器的高频变压器磁芯双向磁化，提高了磁芯利用率。本文研究了导通占空比、开关管导通管压降以及变压器两原边的磁化电感等参数不一致时，导致变压器磁芯偏磁问题。磁芯的磁化状态虽受上述参数的不一致影响而出现单向磁化现象，但不会出现单向磁饱和，双管正激磁集成变换器仍能稳定工作，为能否采用平均电流控制模式或电压控制模式提供了理论依据。文中分析了变压器原边环流产生机理，提出了一种减小环流的方法。使环流减小一半。     

Space Environment Prediction for SZ-4 and SZ-5

The Space Environment Prediction Center (SEPC) of the Center for Space Science and Applied Research of the Chinese Academy of Sciences (CSSAR, CAS)took on the mission of offering the space environment parameters which may be of use to the safety of manned spacecraft. In order to complete the space environment safety guarantee mission for SZ-4 and SZ-5, SEPC improved the space environment monitoring system, database system, prediction result display system, prediction implementation system, etc. For guaranteeing the safety of the airship and cosmonaut in the first manned SZ-5, flying experiment mission,SEPC developed the software for analyzing radiation dose and early-warning software for large debris collision with SZ-5. Three months before the flights of SZ-4 and SZ-5, SEPC began to predict the safe launch period in view of the space environment, and offered timely and valid reference opinions for selecting the safety period. Especially during the mission of SZ-5, SEPC analyzed the space high-energy environment in a pre-arranged orbit and abnormal orbit andevaluated the radiation dose which cosmonauts may encounter in space. The evaluation offered an important reference for cosmonaut safety and decisionmaking in the SZ-5 mission. The calculation of the distribution of large debris and the collision risk assessment at different orbit entry times for SZ-5 provided an important base for the superior department to make flight decisions.     

卫星介质深层充电中的主要物理问题

卫星介质深层充电效应是诱发地球同步轨道卫星运行故障和异常的重要因素之一，通过计算机模拟对介质深层充电的时间常数、电场特征、以及屏蔽、介质厚度和接地方式对充电所致最大电场的影响等主要物理问题进行了详细的分析，并给出了初步的防护措施．     

单向陶瓷基复合材料任意应力本构行为快速计算方法

为了实现快速预测陶瓷基复合材料(CMCs)任意应力加卸载作用后的损伤状态和本构行为,对CMCs任意应力加卸载力学行为进行研究。提出了任意应力加卸载曲线简化方法,得到仅包含决定CMCs损伤状态的等效载荷曲线。基于剪滞模型,直接给出CMCs在等效载荷曲线作用后的滑移区分布,避免对载荷曲线的逐点计算。进而预测了材料的损伤状态和应力应变行为。将原始加卸载曲线带入剪滞模型,计算CMCs滑移区分布和应力应变,并与本文提出的方法进行比较,结果表明,两种计算方法计算的结果一致,说明了本文提出的载荷曲线简化方法和滑移区分布计算方法是可行的。     

横程动态约束的预测-校正再入制导方法

针对大升阻比飞行器再入滑翔制导问题，基于预测-校正制导法，提出一种横程动态约束的侧向制导策略。利用再入过程中横程与剩余航程的近似线性关系，设计边界约束动态变化的横程走廊控制倾侧角反转。对大气密度和飞行器气动参数扰动引起的预测模型不确定性进行在线参数估计。以CAV-L高超声速飞行器为研究对象，进行再入制导仿真。结果表明，对不同航程的再入任务该制导法均能精确引导飞行器飞向目标，侧向制导倾侧角反转时机分布合理，反转次数少。Monte Carlo仿真校验了横程动态约束制导法对再入状态误差和过程扰动具有良好的自适应性和鲁棒性。     

树脂η*和Tg对C/E预浸料黏性的表征

针对复合材料预浸料工艺性缺少可量化表征方法的现状,研究了4种C/E预浸料的黏性及其环氧树脂体系的物理特性。发现预浸料黏性可以通过环氧树脂体系动态复数黏度η*和T_g两个物理量表征,环氧树脂的η*=35 kPa·s附近,T_g=0℃附近预浸料黏性较为合适。     

基于有限元法的电磁铁磁场的计算机定量分析

随着工程领域中对电磁铁磁场分析的计算精度要求的不断提高,要求有新的数值分析方法以适应这一需求,有限元法即是符合这一需求的分析方法。主要阐述了应用有限元法分析数字阀电磁铁问题的基本思想,并运用该方法对产品前期设计进行了精密的计算和性能预测,节省了大量的设计费用,经济可比性较高。     

Robust Navier-Stokes method for predicting unsteady flowfield and aerodynamic characteristics of helicopter rotor

A robust unsteady rotor flowfield solver CLORNS code is established to predict the complex unsteady aerodynamic characteristics of rotor flowfield. In order to handle the difficult problem about grid generation around rotor with complex aerodynamic shape in this CFD code,a parameterized grid generated method is established, and the moving-embedded grids are constructed by several proposed universal methods. In this work, the unsteady Reynolds-Averaged Navier-Stokes(RANS) equations with Spalart-Allmaras are selected as the governing equations to predict the unsteady flowfield of helicopter rotor. The discretization of convective fluxes is accomplished by employing the second-order central difference scheme, third-order MUSCL-Roe scheme, and fifth-order WENO-Roe scheme. Aimed at simulating the unsteady aerodynamic characteristics of helicopter rotor, the dual-time scheme with implicit LU-SGS scheme is employed to accomplish the temporal discretization. In order to improve the computational efficiency of holecells and donor elements searching of the moving-embedded grid technology, the ‘‘disturbance diffraction method" and ‘‘minimum distance scheme of donor elements method" are established in this work. To improve the computational efficiency, Message Passing Interface(MPI) parallel method based on subdivision of grid, local preconditioning method and Full Approximation Storage(FAS) multi-grid method are combined in this code. By comparison of the numerical results simulated by CLORNS code with test data, it is illustrated that the present code could simulate the aerodynamic loads and aerodynamic noise characteristics of helicopter rotor accurately.     

基于消费者视角的品牌竞争力影响因素研究

简要回顾品牌竞争力的研究,文章从消费者视角出来,构建品牌竞争力的影响因素,并选取我国洗发水品牌中＂舒蕾＂品牌作为实证研究对象,运用SPSS应用统计软件进行统计分析,从而得出影响品牌竞争力的因素,并提出对策。     

插铣技术在诱导轮加工中的应用

介绍了采用UG TCL程序算法计算仿真插铣诱导轮的加工工艺.通过DEFORM软件计算插铣诱导轮工艺参数,并经工艺优化得到了一套插铣加工诱导轮的最佳工艺规范.采用该规范加工的诱导轮满足设计要求.装配该诱导轮的发动机通过了热试车考核.