介质材料电磁参数测量综述

扼要介绍了近２０年来介质材料电磁参数测试方法的概况、趋势及技术特点。这些方法包括传输／反射法、多状态法、多厚度法、谐振腔法、自由空间法等。     

机载SAR成像对瞄准线运动补偿的要求

飞机偏离匀速直线运动的运动误差是机载合成孔径雷达成像的基本困难之一。通过详细的理论推导,给出了当飞机沿瞄准线方向同时存在恒定速度误差,恒定加速度误差和正确弦摆动速度误差时,以回波信号压缩波形的主瓣偏移,二次相位误差,三次相位误差以及积分旁瓣比等ＳＡＲ系统图像质量指标的最大允许值表示的机载正侧视ＳＡＲ运动补偿定量要求的解析式。并结合一例子进行了计算分析,所得结论可供有关人员参考。     

Inter-satellite calibration of FengYun 3 medium energy electron fluxes with POES electron measurements

We perform an L-shell dependent inter-satellite calibration of FengYun 3 medium energy electron measurements with POES measurements based on rough orbital conjunctions within 5?min?×?0.1?L?×?0.5 MLT. By comparing electron flux data between the U.S. Polar Orbiting Environmental Satellites (POES) and Chinese sun-synchronous satellites including FY-3B and FY-3C for a whole year of 2014, we attempt to remove less reliable data and evaluate systematic uncertainties associated with the FY-3B and FY-3C datasets, expecting to quantify the inter-satellite calibration factors for the 150–350?keV energy channel at L?=?2–7. Compared to the POES data, the FY-3B and FY-3C data generally exhibit a similar trend of electron flux variations but more or less underestimate them within a factor of 5 for the medium electron energy 150–350?keV channel. Good consistency in the flux conjunctions after the inter-calibration procedures gives us certain confidence to generalize our method to calibrate electron flux measurements from various satellite instruments.     

基于导师科研团队的研究生培养模式探究

本文探讨了基于导师科研团队的研究生培养模式的作用和意义,提出了构建基于导师科研团队的研究生培养模式的主要内容以及关键问题,并对这种培养模式的建立提出了一些想法。     

基于弱耦合的翼伞气动变形数值模拟

对不带气室翼伞和带气室翼伞的气动特性和结构变形进行三维数值模拟,分析气室对翼伞气动特性和结构变形的影响.流场方面,采用有限体积法求解Navier-Stokes控制方程,选用剪切应力输运(SST,Shear-Stress Transport)k-ω湍流模型;结构方面,假定翼伞有初始形状,使用插值方法映射传递流固交界面的压力数据,通过ANSYS计算翼伞伞衣的气动变形.结果表明:气室对阻力影响不大,对升力的影响主要表现在大迎角情况下;翼伞柔性和尺寸大小对其有利迎角的范围影响不大;翼伞的气动变形和最大主应力主要集中在气室中前部分,带气室翼伞由于有肋片加强的缘故,伞衣气动变形较小,一定程度上保证了翼伞的气动特性.     

尿素法制备氮化物陶瓷材料的研究进展

综述了近年来尿素法制备氮化物陶瓷粉体、涂层、纳米管和陶瓷基复合材料等的研究进展,并对其发展趋势作了展望.     

Lunar exosphere influence on lunar-based near-ultraviolet astronomical observations

The potential effect of the lunar exosphere on the near-ultraviolet sky background emission is predicted for Lunar-based Ultraviolet Telescope (LUT: a funded Chinese scientific payload for the Chang’e-III mission). Using the upper limit on the OH concentration inferred from the recent MIP CHACE results, our calculations show that the sky brightness due to the illuminated exosphere is <8.7 photons⁻¹ cm⁻² arcsec⁻² within the wavelength range 245–340 nm. By evaluating the signal-to-noise ratios of observations of an AB = 13 mag point source at a series of sky background levels, our analysis indicates that the detection performance of LUT can be moderately degraded by the lunar exosphere emission in most cases. An AB = 13 mag point source can still be detected by the telescope at a signal-to-noise ratio more than 8 when the OH concentration is less than 2 × 10⁸ molecules cm⁻³. However, the effect on the performance is considerable when the exosphere is as dense as suggested by CHACE.     

S1流场计算技术的改进和完善

采用有黏-无黏相互迭代的研究方法,对已有的S1流场计算程序进行了改进与完善。就数值计算结果与试验结果的对比而言,改进后的S1流场计算程序在精度上基本可以满足工程要求。     

TDS600系列数字示波器自动验收系统

ＴＤＳ６００系列数字示波器自动验收系统，采用人机对话的形式，改变了以往的手动操作验收。以ＲＩＣ３８６计算机为中心，以信号源如：ＳＧ５０３正弦波发生器等为标准，通过ＧＰ－１Ｂ接口总线来编程控制数字示波器，并配以打印机及绘图仪打印结果和波形，对示波器各项功能进行验收，检查仪器的各项指标是否在给定极限范围之内。初学者可根据屏幕上的提示，一步步执行，便可自动进行验收，查看结果。     

含Nd稀土相对高温钛合金低周疲劳裂纹萌生与扩展行为的影响

实验研究了含稀土Ｎｄ高温钛合金中稀土相颗粒与室温及６００℃低周疲劳裂纹萌生与扩展行为的关系。结果表明，疲劳裂纹在距颗粒一定距离的基体中产生，而不在预先开裂或脱粘的颗粒处萌生。裂纹扩展时绕过颗粒并使裂纹扩展路径曲折化。