喷射成形技术在涡轮盘高温合金中的应用

喷射成形是一种新型快速凝固技术,采用这项技术制备的镍基合金,具有细小、球状的晶粒和均一的组织,从而提高其性能。本文综述了喷射成形技术在涡轮盘用镍基高温合金中的应用及其发展与研究现状。     

固体润滑技术在空间机械中的应用

对空间机械润滑的特殊性作了简要的分析,评述了各种固体润滑材料在空间环境中的摩擦磨损性能,介绍了各种固体润滑膜的制备工艺及其在空间机械中的应用情况,并指出了有待进一步研究的问题。     

航天器控制应用的星载计算机技术

介绍了中国研制的用于近地轨道、太阳同步轨道和地球同步轨道航天器的几种主要星载容错计算机的功能和主要特点以及它们的容错结构,并简述了星载控制计算机的发展趋势。     

一种面向工程实际的专家系统的开发构思

面向应用领域中许多难度大,技术复杂的设计课题,本文探讨了专家知识的计算机程序系统。     

Inner Attitude Integration Algorithm Based on Fault Detection for Strapdown Inertial Attitude and Heading Reference System

This article proposes a new inner attitude integration algorithm to improve attitude accuracy of the strapdown inertial attitude and heading reference system(SIAHRS), which, by means of a Kalman filter, integrates the calculated attitude from the accelerometers in inertial measuring unit(IMU), called damping attitudes, with those from the conventional IMU. As vehicle's acceleration could produce damping attitude errors, the horizontal outputs from accelerometers are firstly used to judge the vehicle's motion so as to determine whether the damping attitudes could be reasonably applied. This article also analyzes the limitation of this approach. Furthermore, it suggests a residual chi-square test to judge the validity of damping attitude measurement in real time, and accordingly puts forward proper information fusion strategy. Finally, the effectiveness of the proposed algorithm is proved through the experiments on a real system in dynamic and static states.     

通道间延迟时间差评价结果的不确定度

介绍了四参数正弦波最小二乘法评价通道间延迟时间差指标及不确定度分析和评价过程,同时给出了一个分析评价实例。该过程及结论可应用在对于测量标准进行相应指标的不确定度分析上,也可用于估计指标本身的不确定度。     

Analysis on capabilities of density-based solvers within OpenFOAM to distinguish aerothermal variables in difusion boundary layer

Open source feld operation and manipulation（OpenFOAM）is one of the most prevalent open source computational fluid dynamics（CFD）software.It is very convenient for researchers to develop their own codes based on the class library toolbox within OpenFOAM.In recent years,several density-based solvers within OpenFOAM for supersonic/hypersonic compressible flow are coming up.Although the capabilities of these solvers to capture shock wave have already been verifed by some researchers,these solvers still need to be validated comprehensively as commercial CFD software.In boundary layer where diffusion is the dominant transportation manner,the convective discrete schemes＇capability to capture aerothermal variables,such as temperature and heat flux,is different from each other due to their own numerical dissipative characteristics and from viewpoint of this capability,these compressible solvers within OpenFOAM can be validated further.In this paper,frstly,the organizational architecture of density-based solvers within OpenFOAM is analyzed.Then,from the viewpoint of the capability to capture aerothermal variables,the numerical results of several typical geometrical felds predicted by these solvers are compared with both the outcome obtained from the commercial software Fastran and the experimental data.During the computing process,the Roe,AUSM＋（Advection Upstream Splitting Method）,and HLLC（Harten-Lax-van Leer-Contact）convective discrete schemes of which the spatial accuracy is 1st and 2nd order are utilized,respectively.The compared results show that the aerothermal variables are in agreement with results generated by Fastran and the experimental data even if the1st order spatial precision is implemented.Overall,the accuracy of these density-based solvers can meet the requirement of engineering and scientifc problems to capture aerothermal variables in diffusion boundary layer.     

微波宽频接收前端低噪声的研究

采用格林函数法和FDTD计算法,分别分析和计算了微波、毫米波接收前端中多芯片组件的不同摆放位置对系统的噪声系数和功率增益的影响.理论计算与试验结果吻合,表明微波多芯片组件的位置是影响宽频微波、毫米波接收系统性能的重要因素.     

双组元推进剂质谱检测实验研究

推进剂泄漏检测技术是关系到航天器正常运行和安全发射的关键技术之一。采用燃烧剂，氧化剂的双组元推进剂是航天器推进系统的经常选用的燃料。质谱检测的技术具有同时检测环境中这两种微量成分而不相互干扰的优点，文章简述了双组元推进剂的质谱检测装置，给出对是，四氧化二氮的质谱实验研究方法及检测结果。     

Waveform fusion in sonar signal processing

In active sonar systems, proper selection of the transmitted waveform is critical for target detection and parameter estimation, especially with the existence of clutter (reverberation). Two commonly used waveforms (constant frequency (CF) and linear frequency modulated (LFM)) are studied. Their characteristics are complementary both with respect to their accuracies and their sensitivity to the blind zero-Doppler ridge. Several fusion schemes of the two kinds of waveforms are explored and fusion results are studied both analytically and from simulation. It is concluded that fusion of the information of different waveforms can be not only more robust, but in some cases outright preferable, in term of detection probability and estimation accuracy.