红外隐身材料的现状与展望

综述了国内外红外隐身材料的发展历程，重点介绍了构成红外隐身材料的填料、树脂的研究现状以及近年来开始重点研究的红外兼容型多频谱隐身材料，并且指出了红外隐身材料的发展方向。     

热红外伪装材料的研究及其进展

热红外探测器的高度发展已使应用于目标表面的热红外隐身材料成为飞行器隐身技术中的一个重要组成部分。但对这种材料的发展情况,以往的文献中一向较少涉及。本文以全面、系统的情报调研为基础,着重探讨分析了十余年来国外热红外隐身材料研究工作的基本状况,总结了热隐身材料设计的一般原则,分析了涂料、光学薄膜、多频谱兼容隐身材料和     

多频段隐身材料的研究现状与进展

在现代战争中,为了提高在军事对抗中的竞争实力,隐身技术一直都是各国的重点研究对象,而隐身材料在其中占据了重要位置.本文深入研究了各阶段单一频段隐身材料的发展现状,总结了雷达、可见光、高光谱和红外隐身材料的优势与不足,分析了现阶段各种兼容隐身材料的发展新需求;综述了目前雷达与红外、可见光与红外、高光谱与红外、多频段兼容隐...     

我国航空发动机用几种涂层技术的差距及未来发展

论述了航空发动机隐身、抗冲蚀、防钛火涂层的技术现状.强调研究多元合金化及复合冲蚀涂层、阻燃涂层及阻燃性能测试技术,研究强吸波和低红外发射涂层、宽频带和多频谱隐身、雷达与红外隐身兼容涂层,以促进我国隐身战机的研制.     

多谱兼容隐身材料研究（上）——降温吸波多谱兼容隐身涂料的可能性模型

隐身材料是实现目标隐身的重要途径。随着侦察技术的多频谱（可见光、红外和雷达等多种侦察谱段）化，隐身技术和隐身材料的研究必须满足多谱要求。本文通过对单层涂料与电磁波相互作用分析，建立雷达波吸收模型，预测达到目标吸波技术指标所需要选择的材料的范围；利用能量守恒原理，通过在该层涂料上建立太阳加热后涂料与目标周围环境动态热平衡模型方法，预测降温效果，为材料研制选择技术参数指明方向。通过上述雷达波吸收和热红外降温模型的建立和求解分析，预测单一涂料对地面目标雷达与红外兼容隐身，通过材料参数调整和设计是可能的，为兼容性多谱隐身材料的研制指明的方向。     

激光、红外隐身兼容涂料的前景分析

红外探测技术、激光探测技术、电子战等因素使得红外波段中的隐身技术变得更为重要。在同一波段范围同时达到红外与激光的隐身兼容是热平衡理论所面临的难题。要做到红外和激光的隐身兼容，就必须克服两者对材料的一对矛盾要求。在分别介绍了红外、激光隐身的原理后，提出了红外激光复合隐身的设想，并分析了两种央技术的互相制约及兼容的可能性。     

红外隐身涂层及对雷达吸波性能的影响

研究了红外雷达兼容隐身涂层红外发射率及雷达波隐身兼容性的影响因素,包括填料的类型、质量分数及涂层厚度。研究表明,以填充30wt%的HW-3型铝粉为填料,制备的涂层厚度为20μm时,涂层红外发射率达到0.25,能大幅降低材料表明红外辐射温度,且对微波隐身兼容性良好。     

典型亚声速飞翼布局无人机红外隐身特性分析

隐身技术作为提高作战生存力的关键环节,是复杂对抗环境下武器装备信息化作战的最重要技术指标。飞翼布局以其独特的隐身优势,成为无人作战飞机首选布局形式。文章以超低RCS亚声速飞翼布局无人机平台为基础,从多频谱隐身特征平衡设计出发,针对其采用低发射率材料前后的红外隐身特性进行了对比分析,验证了红外隐身措施的有效性。     

多谱兼容隐身材料研究（中）——防护工程应用兼容性分析

本文对国内外兼容型隐身材料发展现状做了介绍，对防护工程多谱隐身应用进行了分析，并简要介绍了降温吸波兼容隐身涂料的实验成果。     

防护工程用隔热吸波兼容性隐身材料研究——兼容机理与模型设计研究

针对隐身材料在防护工程应用中存在的问题，在分析归纳的基础上，根据电磁波与材料的相互作用理论，提出了隔热吸波多谱兼容隐身材料物理模型，并根据该物理结构模型进行了材料设计，可为研制适用于防护工程的多谱兼容隐身材料提供理论指导。     

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.      

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.     

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 ℃).     

超声速燃烧数值模拟中的湍流与化学反应相互作用模型

高精度数值模拟有助于理解超声速湍流燃烧中湍流与化学反应的相互作用,可为发动机燃烧室等工程应用设计提供可靠的预测模型。除直接数值模拟外,目前在湍流燃烧应用中使用的大涡模拟和雷诺平均Navier-Stokes模拟均需要借助模型模化发生在湍流小尺度上的流动与化学反应过程对湍流大尺度运动的影响。现有的湍流与化学反应相互作用模型大致可分为:火焰面类模型和概率密度函数类模型,2类模型在不同的应用中各自具有优势和局限性。此外,现有模型大都基于低马赫数燃烧,而超声速燃烧中通常会伴随快速混合、局部熄火和再着火以及激波等复杂过程,这为发展其中的湍流与化学反应相互作用模型提出了更多的挑战。     

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。     

Jet Vectoring Control Using a Novel Synthetic Jet Actuator

A primary air jet vectoring control system with a novel synthetic jet actuator (SJA) is presented and simulated numerically. The results show that, in comparison with an existing traditional synthetic jet actuator, which is able to perform the duty of either “push” or “pull”, one novel synthetic jet actuator can fulfill both “push” and “pull” functions to vector the primary jet by shifting a slide block inside it. Therefore, because the new actuator possesses greater efficiency, it has potentiality to replace the existing one in various appli- cations, such as thrust vectoring and the reduction of thermal signature. Moreover, as the novel actuator can fulfill those functions that the existing one can not, it may well be expected to popularize it into more flow control systems.     

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.     

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.