Modeling of Heat Conduction in Thermoplastic Honeycomb Core/Face Sheet Fusion Bonding

Honeycomb sandwich materials have been widely used in aerospace industry as secondary structural materials or interior panels. Recently the research of full thermoplastic honeycomb sandwich materials has been of interest due to their recyclability. In their production, they usually demand an adhesive-free process, namely fusion bonding, to connect thermoplastic honeycomb core and face sheets. It is a heat induced process where a parameter of temperature should be well controlled to guarantee the product quality. This article presents a mathematical model of heat conduction to analyze the transient temperature distribution from heating tools towards inner part of the core under fusion bonding conditions. In order to simplify the complexity of 3D honeycomb geometry, a homogenization method is used to obtain average thermal properties of the honeycomb along the major heat flux direction. The model is validated by comparing with the results of in-situ temperature measurement during fusion bonding. The presented model can also be applied to analyzing general out-of-plane heat conduction through honeycomb sandwich structures made from other materials.     

COMPASS/GPS双系统四星定位算法研究

针对COMPASS系统处于组网期,有效卫星缺失引起双系统卫星导航接收机暂时性无法定位的问题,提出一种双系统四星定位算法。利用完备条件下的定位信息,采用最小二乘拟合法或α-β滤波法,将完备条件下解算得到的COMPASS与GPS的系统钟差线性化,得到该钟差在非完备条件下的值,再结合可视卫星,在双系统四星条件下短时间内保持定位。算法无需引入其他设备,不依赖电子地图。经仿真验证,算法有效可行,在双系统四星条件下定位精度较高,且卫星信号恢复到完备条件后,定位精度能迅速恢复到完备条件下的水平。     

强化图书馆在高校创新教育中对学生的指导作用

图书馆作为高校教育的一部分,同样肩负着创新教育的责任。高校图书馆提供的文献信息检索、丰富的信息资源、有序的信息管理系统、独特的教育职能、良好的信息环境对学生的信息素质增强非常重要。图书馆应重视教育和培养学生创造思维的能力,培养学生将获取到的知识进行分解、加工、整合成新知识的能力,使图书馆真正成为高校创新教育的第二课堂。     

基于LABVIEW虚拟仪器的环境质量检测系统设计

主要介绍了基于红外探测检测座舱中气体组成成分的方法，基于LABVIEW软件开发平台设计了虚拟仪器．实现了显示浓度波形及浓度值的功能．     

IBAD法沉积TiN薄膜的机械和耐腐性

用离子束辅助沉积(IBAD)方法在医用不锈钢317L基底上沉积TiN陶瓷薄膜。通过X射线衍射(XRD)和俄歇电子能谱(AES)分析研究了薄膜的微结构；测试了薄膜的耐磨性及薄膜与基底的附着力：运用电化学腐蚀的方法检测了薄膜在Hank’s模拟体液中的耐腐蚀性能。研究结果表明：用高、低能氮离子束兼用的IBAD方法沉积TiN多晶薄膜后，材料表面结构和性能发生明显改变。表面硬度和耐磨性有明显提高，在Hank’s模拟体液中显示出更强的抗腐蚀能力。     

计算机辅助机用铰刀设计

介绍了基于VB环境的铰刀CAD系统的构成与主要模块功能。本设计是以Visual Basic 6．0为开发工具，以Auto CAD2002为图形输出环境，来开发机用铰刀计算机辅助设计软件。该系统对输入的铰刀数据加以分析计算，然后调用数据库中存储的相关参数，自动驱动CAD完成零件图绘制。     

丁羟推进剂粘合剂体系固化催化研究

研究了乙酰丙酮铁（Ｆｅ（ＡＡ）３）二月桂酸二丁基锡（Ｔ－１２）和三苯基铋（ＴＰＢ）三类催化剂对丁羟（ＨＴＰＢ）推进剂粘合剂体系固化催化性能的影响,实验结果表明,ＴＰＢ是丁羟推进剂粘合剂体系比较理想的固化催化剂。     

电子回旋共振推力器C/C复合材料栅极的力学性能

为了研究电子回旋共振推力器在搭载火箭升空过程中,过载和振动环境对栅极带来的影响,采用有限元分析软件建立了10 cm C/C复合材料栅极的有限元分析模型,计算分析了不同C/C复合材料栅极的力学性能、频率响应和振动模态。结果表明:20g过载下,栅极的最大变形量为6.12×10-4mm;在5~800 Hz激振下,栅极频率响应的最大位移为2.3×10-6mm;过载对栅极的影响要大于振动对它的影响,但是这两个值都在安全门限内;综合分析栅极频响和模态分析的计算结果,栅极仅在其第一阶模态处于外界激振发生共振。     

一种新的SAR图像目标检测方法

基于统计特性的恒虚警率(CFAR)算法和小波多分辨率分析方法很难检测到微弱的、小的和隐藏的目标。合成孔径雷达(SAR)成像机理是相干成像,相干相位信息为目标的检测提供了可能性。从相干成像机理出发,结合恒虚警率和背景杂波分布模型,提出了一种新的SAR图像目标检测算法,即相干性CFAR目标检测算法,并且针对图像相干源提出了亚像元空间域源算法。实验证明,该方法是可行的、有效的,有利于SAR图像的理解和应用。     

International space programmes and policies : N. Jasentuliyana and Ralph Chipman, eds North Holland, Amsterdam and New York, 1984, 552 pp, $65.00

The Second United Nations Conference on the Exploration and Peaceful Uses of Outer Space ( 82) identified crucial problems and made recommendations on strategies for developing countries to bridge the gap with advanced nations in the area of space technology. This article addresses some issues which, although implicit in the Report, are not discussed in detail therein. The role of space science and related scientific research is particularly emphasized. Close attention is paid to the role of human factors, such as the motivation to conduct research, the motivation to engage in international cooperation, and the motivation to utilize and exploit space. Possible opportunities for space research for developing countries, as well as relevant issues concerning management of space, are briefly discussed.