俄罗斯国家航空工艺研究院（НИАТ）的现状与未来

俄罗斯国家航空工艺研究院（НИАТ）的现状与未来俄罗斯国家航空工艺研究院院长Ｏ．Ｃ西罗特金［编者按］俄罗斯国家航空工艺研究院是专门从事航空工艺技术研究的科研机构，本文是该院院长Ｏ．Ｃ．西罗特金在建院７５周年之际发表于俄罗斯《航空工业》１９９５年第１１...     

访印手记

本文简要介绍了印度国家宇航研究院的基本情况，对中印两国今后进行航空科技合作提出了合理的建议与设想。     

中国航空工业空气动力研究院简介

根据国家关于科研院所体制改革总体要求和结合中国航空工业第一集团公司结构调整总体布局 ,哈尔滨空气动力研究所同沈阳空气动力研究所联合重组成立中国航空工业空气动力研究院，于 2000年 7月 26日正式宣告成立。 新组建的研究院共有员工 850人，科技人员 600名，其中研究员 31人，副高级技术人员 150人，工程师 300人。 1982年获得空气动力学专业工学硕士的招生培养权。 1997年通过了 ISO－ 9001质量认证和国家军用标准（ GJB/Z9001－ 96)质量保证体系认证。 空气动力研究院拥有十分雄厚的技术实力，集高低速空气动力实验、飞机先进气…     

美国国家标准与技术研究院NIST(National Institute of Standards and Technology)的近况

美国国家标准与技术研究院NIST的前身为原美国国家标准局NBS(National Bere-au of Standards),创建于1901年,原属美国商业部,1988年8月23日正式改名为美国国家标准与技术研究院NIST。改名后,除保留原有的工作内容(发展标准和测量技术,提供试验数据,方法和标准服务)外,另外增加了新的工作内容(帮助企业接受先进的科学技术,提高企业在国内外市场上的竞争能力,面向中小型企业开发新技术、新产品,进行技术服务和技术转让)。     

英国吉内蒂克集团和它的试飞机队

自上个世纪90年代以来,英国航空航天国防科研机构进行了三次重大改革,将包括皇家航空航天研究院在内的4个研究院合并,组成相对独立的国防研究局(DRA),把除核武器以外的、包括英国飞机和军械评估研究院(A&AEE)在内的4个试飞鉴定机构划入DRA,并改名为国防鉴定与研究局(DERA),使研究和试验试飞鉴定工作合在一起,接着让DERA大部分民营化,组成吉内蒂克集团,形成一套独树一帜的更加面向用户、更加面向市场和为国家减负、让机构增收的双赢局面     

励精图治 敢为人先 誓言做大数控机床产业

2002年,北京机电院高技术股份公司由北京市机电研究院改制而成,研究院的前身是北京市第六机床厂,80代开始研制数控机床,80代末研制加工中心,90年代初引进美国辛辛那提的马刀立式加工中心技术并合作生产,“九五”期间着手实施国产化和产业化,并成为国家“数控机床产业化工程”骨干企业之一。     

联合 重组 再创辉煌──热烈祝贺中国航空工业空气动力研究院成立

根据国家关于科研院所体制改革总体要求，结合中国航空工业第一集团公司结构调整总体思路，哈尔滨空气动力研究所与沈阳空气动力研究所联合重组成立中国航空工业空气动力研究院，我们向该研究院的成立表示热烈祝贺和美好祝愿。 将两所合并成立中国航空工业空气动力研究院，是贯彻中航第一集团公司“以人为本、科技兴业、航空报国”的方针，增强航空空气动力研究实力和经济实力的重大决策，是深化改革，完善国防科技工业管理体制，加速航空发展，增强竞争力的重大举措。合并的目的是为了加快航空空气动力专业技术发展，提高航空空气动力学科…     

橡胶硫化烟气治理技术通过院级鉴定

航天部一院七○三所研制的橡胶硫化烟气治理技术已于6月17日通过院级鉴定。国家环保局、北京市环保局、化工部橡胶司、北京工业大学、北京橡胶研究院、中国环境报等有关单位的领导和专家参加了鉴定会。与会者一致认为.用“臭氧为氧化     

我所看到的德国宇航研究院

1994 年10 月至1995 年1月,笔者在德国宇航研究院(DLR)的科隆总部工作学习了3个月,其间重点了解该院的INFO-DB信息管理系统,同时对德国宇航研究院和整个德国航空工业的情况进行了调查,下面简要介绍笔者所了解的德国宇航研究院的情况。经费不足日前,德国宇航研究院总的经济情况并不很好,各级政府部门为其拨款逐年递减,其差额部分要靠研究院自己挣钱来弥补。德国宇航研究院目前采取了一系列开源节流的办法来解决经费不足的     

访问俄罗斯印象

初冬时节,应俄罗斯中央航空流体动力研究院国家科研中心的邀请,以副总裁汪亚卫为首的中国航空信息中心代表团一行四人于1994年10月28日至11月11日访问了莫斯科。代表团在ЦАГИ的细致安排和中航技驻莫斯科代表处的帮助下,不仅     

The effect of inlet conditions on the flow and heat transfer in multiple rotating cavity with axial throughflow

This paper discusses experimental results from two different build configurations of a heated multiple rotating cavity test rig.Measurements of heat transfer from the discs and tangential velocities are presented.The test rig is a 70% full scale version of a high pressure compressor stack of an axial gas turbine engine.Of particular interest are the internal cylindrical cavities formed by adjacent discs and the interaction of these with a central axial throughflow of cooling air.Tests were carried out for a range of non-dimensional parameters representative of high pressure compressor internal air system flows(Re up to 5×106 and Rez up to 2×105).Two different builds have been tested.The most significant difference between these two build configurations is the size of the annular gap between the(non-rotating) drive shaft and the bores of the discs.The heat transfer data were obtained from thermocouple measurements of surface temperature and a conduction solution method.The velocity measurements were made using a two component,LDA system.The heat transfer results from the discs show differences between the two builds.This is attributed to the wider annular gap allowing more of the throughflow to penetrate into the cavity.There are also significant differences between the radial distributions of tangential velocity in the two builds of the test rig.For the narrow annular gap,there is an increase of non-dimensional tangential velocity V/Ωr with radial location to solid body rotation V/Ωr=1.For the wider annular gap,the non-dimensional velocities show a decrease with radial location to solid body rotation.      

Effects of Mo on the Microstructure and Hydrogen Sorption Properties of Ti-Mo Getters

The effects of Mo on the microstructure evolution, porosity and hydrogen sorption properties of Ti-Mo getters are investigated in this work. The results show that the addition of Mo prolongs the densification process of Ti-Mo getters and results in a significant amount of sintered pores. With the Mo content increasing, the porosity of getters firstly increases reaching the maximum value as it at- tains about 7.5wt.%, and then drops. At the room temperature, the hydrogen sorption property of getters increases progressively with the Mo content increasing, but the tendency is not very clear before its content lies below 2.5wt.%. When the Mo content achieves about 7.5wt.%, the hydrogen sorption property proves to be the best. The discussion is made about the above mentioned phenomena inclusive of hydrogen sorption properties of getters under different activation conditions (from 500-750 ℃).     

An SOR Implicit Time-accurate Scheme in Calculating Unsteady Flows

A new time-accurate marching scheme for unsteady flow calculations is proposed in the present work. This method is the combination of classical Successive Over-Relaxation (SOR) iteration method and Jacobian matrix diagonally dominant splitting method of LUSGS. One advantage of this algorithm is the second-order accuracy because of no factorization error. Another advantage is the low computational cost because the Jacobian matrices and fluxes are only calculated once in each physical time step. And, the SOR algorithm has better convergence property than Gauss-Seidel. To investigate its accuracy and convergency, several unsteady flow computa- tional tests are carried out by using the proposed SOR algorithm. Roe’s FDS scheme is used to discritize the inviscid flux terms. Un- steady computational results of SOR are compared with the experiment results and those of Gauss-Seidel. Results reveal that the numerical results agree well with the experimental data and the second-order accuracy can be obtained as the Gauss-Seidel for unsteady flow computations. The impact of SOR factor is investigated for unsteady computations by using different SOR factors in this algorithm to simulate each computational test. Different numbers of inner iterations are needed to converge to the same criterion for different SOR factors and optimal choice of SOR factor can improve the computational efficiency greatly.     

Nonlinear Adaptive Slewing Motion Control of Spacecraft Truss Driven by Synchronous V-gimbaled CMG Precession

The slewing motion control of a truss arm driven by a V-gimbaled control-moment-gyro (CMG) is a nonlinear control problem. The V-gimbaled CMG consists of a pair of gyros that must precess synchronously. The moment of inertia of the system, the angular momentum of the gyros and the external disturbances are not exactly known. With the help of feedback linearization and recursive Lyapunov design method, an adaptive nonlinear controller is designed to deal with the unknown items. Performance of the proposed controller is verified by simulation.     

适于低轨卫星IP网络的单核共享树组播算法(英文)

为了解决低轨卫星IP网络中现有典型源组播算法的信道资源浪费问题,本文提出了一套单核共享树组播算法,即核心群合并共享树(CCST)和加权核心群合并共享树(w-CCST)算法。CCST 算法包括动态近似中心(DAC)选核方法和核心群合并组播路径构建方法。DAC方法专为周期、规律运动的低轨卫星网络提出,不需要复杂的星上计算。在核心群合并方法中,以核节点作为初始核心群,通过核心群和剩余组成员的最短路径方法逐步扩展直至整棵组播树构建完成,从而使得组播树的树代价最小,大大提高了网络的带宽利用率和组播传输效率。w-CCST 算法中所提出的加权因子可以调整树代价和端到端传播时延之间的折衷程度,因此,可以通过调整加权因子来适度增大树代价、降低端到端传播时延以支持某些端到端时延要求苛刻的实时组播业务。最后,与低轨卫星 IP 网络中典型算法进行了性能比较,仿真结果说明,CCST 算法的平均树代价比其它算法显著降低,w-CCST 算法的平均端到端传播时延小于 CCST 算法。     

GA-Based Model Predictive Control of Semi-Active Landing Gear

Semi-active landing gear can provide good performance of both landing impact and taxi situation, and has the ability for adapting to various ground conditions and operational conditions. A kind of Nonlinear Model Predictive Control algorithm （NMPC） for semi-active landing gears is developed in this paper. The NMPC algorithm uses Genetic Algorithm （GA） as the optimization technique and chooses damping performance of landing gear at touch down to be the optimization object. The valve＇s rate and magnitude limitations are also considered in the controller＇s design. A simulation model is built for the semi-active landing gear＇s damping process at touchdown. Drop tests are carried out on an experimental passive landing gear systerm to validate the parameters of the simulation model. The result of numerical simulation shows that the isolation of impact load at touchdown can be significantly improved compared to other control algorithms. The strongly nonlinear dynamics of semi-active landing gear coupled with control valve＇s rate and magnitude limitations are handled well with the proposed controller.     

Research on Auto-detection for Remainder Particles of Aerospace Relay Based on Wavelet Analysis

Aerospace relay is one kind of electronic components which is used widely in national defense system and aerospace system. The existence of remainder particles induces the reliability declining, which has become a severe problem in the development of aerospace relay. Traditional particle impact noise detection (PIND) method for remainder detection is ineffective for small particles, due to its low precision and involvement of subjective factors. An auto-detection method for PIND output signals is proposed in this paper, which is based on direct wavelet de-noising (DWD), cross-correlation analysis (CCA) and homo-filtering (HF), the method enhances the affectiv-ity of PIND test about the small particles. In the end, some practical PIND output signals are analysed, and the validity of this new method is proved.     

Preparation of Highly Dispersed Antimony-doped Tin Oxide Nano-powder via Ion-exchange Hydrolysis of SnCl4 and SbCl3 and Azeotropic Drying

Antimony-doped tin hydroxide colloid precipitates have been synthesized by hydrolysis of SnCl4 and SbCl3 using: (1) an ion-exchange hydrolysis to remove chlorine ions, and (2) isoamyl acetate as an azeotropic solvent to obviate water. The obtained dried powder is of high dispersivity without any need for further grinding. The size and dispersivity of the final particles are investigated with the aid of TG-DTA, BET, XRD and TEM. After having calcined, the antimony-doped tin oxide nanopowder possesses a tetragonal rutile structure with high dispersivity, uniform particles and low hard agglomeration.     

Large Amplitude Flexural Vibration of the Orthotropic Composite Plate Embedded with Shape Memory Alloy Fibers

研究了形状记忆合金(SMA)纤维混杂复合材料大挠度层合板的非线性自由与受迫振动特性。基于描述SMA力学行为的Brinson理论以及层合板材料性能预测的混合率,建立了SMA纤维混杂复合材料大挠度层合板的本构方程,基于对称层合各向异性弹性板的非线性理论,建立了以横向挠度和应力函数表示的板的横向振动方程和相容方程。采用Galerkin近似解法将振动方程化为时间变量的含有3次非线性项的Duffing型常微分方程,采用谐波平衡法(HBM)获得系统的固有频率方程和强迫振动稳态频率响应方程。数值计算表明,非线性板自由振动频率比与激励温度的关系具有与线性板相同的特征,马氏体相向奥氏体相转变阶段温度对板的振动频响特性曲线的影响最显著,同时也讨论了SMA纤维含量、板的纵横比以及自由振动幅值对板的非线性频率比的影响。