树脂基复合材料缺陷表征与评价方法研究综述

复合材料结构中的制造缺陷严重影响航天装备的服役性能,如何实现复合材料缺陷的高精度检测表征与评价对航天装备的安全性设计意义重大。针对树脂基复合材料缺陷的先进表征技术及评价方法进行概述,重点介绍了复合材料成型工艺与典型缺陷类型、常用复合材料缺陷检测与原位表征技术和复合材料缺陷分析评价方法。通过对复合材料缺陷研究现状的梳理,可见计算机断层扫描技术和基于图像的数值计算方法正以其独特的精确度优势在复合材料缺陷的表征与分析领域崭露头角。同时还对先进的复合材料检测与评价技术在航天装备中复合材料结构安全性设计与可靠性分析方面的应用和发展趋势进行了展望。     

ZnO粉末质子辐照损伤效应

文章研究了90keV质子辐照作用下ZnO粉末的辐照损伤机制。ZnO粉末的质子辐照损伤方式以电离效应为主,质子辐照后ZnO粉末表面产生大量的氧空位型缺陷(Vo**,Vo*和Vo)。氧空位型缺陷的产生是ZnO粉末光谱反射系数下降的主要原因。实验结果表明:质子辐照下,ZnO粉末光学性能退化主要发生在可见光区,在红外区间ZnO粉末光学性能退化不明显。     

基于内模PID鲁棒控制的飞行仿真伺服系统设计

针对飞行仿真伺服系统高频响、宽调速、高精度、超低速和鲁棒性要求，提出了内模PID鲁棒控制的有效方法。在探讨伺服系统数学模型的基础上，推导出一种飞行仿真伺服系统的内模PID鲁棒控制律，并将其应用于某型飞行仿真伺服系统，该伺服系统采用了电流、速度和位置三闭环控制结构。仿真试验表明：文中提出的内模PID鲁棒控制律使飞行仿真伺服系统获得了优良的跟踪性能，具有很强的抗干扰性和鲁棒性，可以很好地满足飞行仿真伺服系统的各项性能指标要求。     

煤体变形局部化的梯度塑性理论研究

摘 要 本文采用白光数字散斑相关方法对煤在单轴压缩下变形破坏进行研究，定量的测出了煤的变形局部化带宽度。并通过应变梯度塑性理论，在屈服函数中引入应变梯度二阶项。采用Drucker－Prager准则解析得出了煤试件的变形局部化带宽度公式并根据试验确定煤的材料内部长度。     

克服旋转导弹螺旋运动的方法研究

本文结合旋转导弹自身的特点，提出了一种通过主动控制弹体内部活动质量块的运动来克服旋转弹螺旋运动的方法，这将有助于提高旋转导弹的合中精度。文中针对大气层外飞行的旋转导弹进行仿真研究，计算结果证实了该方法的有效性和可行性。     

Convection of liquid with internal heat release in a rotating container

The convection of heat-generating fluid in a rotating horizontal cylinder is experimentally investigated. The threshold of convection excitation, the structure of convective flows and the heat transfer in the cylinder depending on the heat release capacity, liquid viscosity and aspect ratio of the cavity are studied. It is found that the average convection is excited by the thermovibrational mechanism —the gravity force, rotating in the cavity frame, produces the oscillations of non-isothermal fluid relative to the wall, which in turn result in excitation of mean convective flows. It is shown that the structure of convective flows depends on the dimensionless velocity of rotation. At relatively low rotation velocity the convection develops in the form of a periodic system of vortices regularly distributed along the cylinder axis. The threshold of excitation (critical value of vibration parameter) of three-dimensional vortex structures grows with rotation velocity. Above some definite rotation velocity the convection develops as two-dimensional rolls parallel to the axis of rotation. The threshold of two-dimensional structures excitation does not depend on the rotation velocity. Besides the structure of thermal convective flows the analysis of the relatively weak currents generated by the inertial waves below the threshold of convection is performed.     

多回路内定标的星载散射计接收通道设计

文章介绍了星载微波散射计多耦合回路内定标方法的原理及接收机的几种接收通道形式;在此基础上,从隔离度、定标精度等方面进行分析,提出了一种多耦合回路内定标的星载散射计接收通道设计方案。     

用弯剪法计算两向正交正放平板网架各杆内力

本文在节点法和截面法的基础上，将两者融为一体，为计算两向正交正放平板网架各杆内力，提供了一种新颖方法，称其为弯剪法，文中引用了实例，结果与其它方法完全一致，并符合实际，这就证实了本法的有效性和可靠性，有一定的参考价值。     

Progress in helicopter infrared signature suppression

Due to their low-attitude and relatively low-speed fight profiles, helicopters are subjected to serious threats from radio, infrared(IR), visual, and aural detection and tracking. Among these threats, infrared detection and tracking are regarded as more crucial for the survivability of helicopters. In order to meet the requirements of infrared stealth, several different types of infrared suppressor(IRS) for helicopters have been developed. This paper reviews contemporary developments in this discipline, with particular emphasis on infrared signature suppression, advances in mixer-ejectors and prediction for helicopters. In addition, several remaining challenges, such as advanced IRS, emissivity optimization technique, helicopter infrared characterization, etc., are proposed, as an initial guide and stimulation for future research. In the future, the comprehensive infrared suppression in the 3–5 lm and 8–14 lm bands will doubtfully become the emphasis of helicopter stealth. Multidisciplinary optimization of a complete infrared suppression system deserves further investigation.     

浅析公务机市场的发展

分析了未来全球公务机市场的发展趋势,介绍了某国产公务机的总体布局和内饰特点,并与国外知名品牌公务机的技术性能进行了对比。同时对国产公务机市场发展前景进行了展望。