环向圈连带冠叶片的动态分析

 本文将动态子结构方法中链式加载技术与群论算法相结合,提出环向固连带冠叶片动力特性分析的一种新方法。文中列出了分析步骤与具体公式,并有实例的计算结果。该方方法适用于研究具有带冠叶片的单级转子中,“冠”的整体效应。     

高能CO2激光腔镜高反介质薄膜的传输特性

为了获得适用于高能CO2激光器的高抗破坏阈值高反薄膜,以10.6μm高反膜ZnSe/YbF3,PbTe/BaF2膜系为例,数值模拟了激光在高反介质膜中的传输的场特性;给出了激光在多层介质膜中的场强分布、温度场分布及热应力分布。结果表明硅镜基体上的PbTe/BaF2膜系所需膜层厚度小、膜层数少,反射率可高达99.98%。     

计算机辅助公差设计与分析的研究现状及展望

对目前计算机辅助环境下的设计公差和工序公差的设计与分析、尺寸公差和形位公差的确定、公差设计理论以及计算机辅助公差的应用现状等多方面进行了归纳和概括,分析了当前这些技术和理论的不足,并结合当前的实情,展望了计算机辅助公差设计与分析技术的发展趋势.     

SRM 纤维缠绕壳体的蒙特卡罗随机有限元分析

采用蒙特卡罗随机有限元方法，结合复合材料壳体力学、纤维缠绕理论等知识，分析了固体火箭发动机纤维缠绕壳体在燃气内压随机变化作用下的应力响应，绘出应力分布曲线，为固体火箭发动机结构可靠性评估奠定基础。     

六喷管超音速引射器性能的理论分析和实验研究

对某一定尺寸的六喷管超音速引射器进行气动性能的实验研究。结果表明：随着主次流压比Ｐ＊ｐ／Ｐ＊ｓ增加，引射系数及修正引射系数下降；当引射系数增加时，混合管动量修正系数Ｋｍ下降，但主喷管流量系数μ变化不大。对上述工况进行理论计算的结果与实验数据符合良好。     

室温贮存对树脂粘度和加压点的影响

讨论了５４０５改性双马来酰亚胺树脂基体在室温下，贮存时间对粘度以及对固化过程中加压点的影响，给出了相应的计算方法。     

Phased array of large reflectors for deep-space communication

In this paper the problem of uplink array calibration for deep-space communication is considered. A phased array of many modest-size reflectors antennas is used to drastically improve the uplink effective isotropic radiated power of a ground station. A radar calibration procedure for the array phase distribution is presented using a number of in-orbit targets. Design of optimal orbit and the number of calibration targets is investigated for providing frequent calibration opportunities needed for compensating array elements phase center movements as the array tracks a spacecraft. Array far-field focusing based on the near-filed in-orbit (low Earth orbit (LEO)) calibration targets is also presented and array gain degradation analysis based on the position error of the array elements and in-orbit targets has been carried out. It is shown that errors in the in-orbit targets positions significantly degrade the far-field array gain while the errors in array elements positions are not very important. Analysis of phase errors caused by thermal noise, system instability, and atmospheric effects show insignificant array gain degradation by these factors     

The Pre-CME Sun

The coronal mass ejection (CME) phenomenon occurs in closed magnetic field regions on the Sun such as active regions, filament regions, transequatorial interconnection regions, and complexes involving a combination of these. This chapter describes the current knowledge on these closed field structures and how they lead to CMEs. After describing the specific magnetic structures observed in the CME source region, we compare the substructures of CMEs to what is observed before eruption. Evolution of the closed magnetic structures in response to various photospheric motions over different time scales (convection, differential rotation, meridional circulation) somehow leads to the eruption. We describe this pre-eruption evolution and attempt to link them to the observed features of CMEs. Small-scale energetic signatures in the form of electron acceleration (signified by nonthermal radio bursts at metric wavelengths) and plasma heating (observed as compact soft X-ray brightening) may be indicative of impending CMEs. We survey these pre-eruptive energy releases using observations taken before and during the eruption of several CMEs. Finally, we discuss how the observations can be converted into useful inputs to numerical models that can describe the CME initiation.     

基于Riccati方程的离散容错控制系统设计

基于离散系统的Ｒｉｃｃａｔｉ方程，提出一种对传感器失效具有完整性的离散控制系统的设计方法，给出了完整性设计方法的设计步骤，并用设计实例验证了该方法的有效性．该方法还可推广用于执行器失效的情况．     

音乐三周年的房子

“我是陈涤”“我是李健”“我是李晖”“我是陈姚”“我们喜欢在音乐里过简单的快乐生活”如此直白的自我介绍，透着几分成熟和自信，坐在我们面前的这四个就是音乐房子的主人。