超标量RISC芯片88110得到军方的重视

超标量ＲＩＳＣ芯片８８１１０得到军方的重视１９９３年３月，Ｍｏｔｏｒｏｌａｊｂ司军事产品开发部决定出售基于超标量ＩＲＳＣ８８１１０军用规范芯片的多芯片模块（ＭＣＭ），这种模块采用了ＩＢＭ／ｋ司的Ｃ．“例装式”４块技术。这一决定的背景是：美国高性能计算...     

从FMS走向RMS--可重配制造系统(中)

5　可重配机床 (ＲＭＴ)如前所述 ,ＲＭＳ由ＲＭＴ和ＲＣＳ两大部分组成。ＲＭＴ是一种新型、基于机床模块库中的机床模块的集成来实现机床设计的方法。每一种机床模块能够提供一种基本运动 ,这是一种将机床设计转换成通过对机床模块合理选择的数学处理方法 ,可产生出新类型的机床。机床模块化设计技术已存在好多年了 ,但从构造制造系统的观点看 ,则是最近几年才提出的。模块化设计技术已被许多设备制造商在现行机床(特别是在数控加工中心、车削中心和ＦＴＬ设备 )设计中采用。一种面向模块对象 (如主轴、进给驱动装置、结构件部件 )和结构…     

用DSC曲线求EML─2，4固化环氧树脂的动力学参数

ＥＭＩ─２，４固化环氧Ｅ─５１的反应是由三个基本反应组成的复杂反应。本文用一张ＤＳＣ图，在二者质量比为０．０４２３６６时，求出其固化反应的表观动力学参数：ｎ＝０，Ｅ＝１．８１×１０￣５Ｊ／ｍｏｌ，Ａ＝３．４×１０￣２２ｓ￣－１。并发现二者质量比在２５％附近时．ＤＳＣ图出现双峰；固化剂用量不同时有不同的动力学参数。     

IGHz Power4芯片整装待发

ＩＢＭ在ＨｏｔＣｈｉｐｓ大会上首次展出了其ＩＧＨｚ测试版芯片Ｐｏｗｅｒ４，准备装备其ＡＳ／４００和ＲＳ／６０００服务器系列产品。ＩＢＭ同时还开发了同步液流水线接口相补充，使Ｐｏｗｅｒ４的总线速度超过５００ＭＨｚ．ＩＢＭ称，Ｐｏｗｅｒ４的目的不仅是推出一款高性能处理器，而且是一种高性能服务器．ＩＢＭ希望Ｐｏｗｅｒ４能够用于Ｗｅｂ服务器中，运行电子商务应用软件或复杂的科技和工程应用软件。ＩＢＭ装备新处理器的ＡＳ／４００及ＲＳ／６０００服务器要到２００１年下半年才能出台．Ｐｏｗｅｒ４在一块芯片上容纳了…     

Si_3N_4－SiC纤维先驱体──低分子量聚硅氮烷的合成与分析

以Ｍｅ_２ＳｉＣｌ_２、ＭｅＳｉＨＣｌ_２（式中Ｍｅ代表ＣＨ_３）或其混合物与ＮＨ_３反应制得低分子量聚硅氮烷，该产物是制备Ｓｉ_３Ｎ_４－ＳｉＣ纤维先驱体的基本原料。研究了不同配比的Ｍｅ_２ＳｉＣｌ_２／ＭｅＳｉＨＣｌ_２混合物氨解反应所需的时间，氨解产物的物理性能、分子量及其分布，着重分析了氨解产物的结构。     

总线接口模块小型化与机载电子设备可靠性增长

增长机载电子设备可靠性指标的有效途径之一是数字电路的小型化。本文通过计算航空电子总线接口模块（ＭＢＩ）的小型化过程三个阶段（采用中小规模集成电路设计ＭＢＩ；采用超大规模集成电路和ＡＳＩＣ技术设计ＭＢＩ；采用ＳＭＴ表面封装和二次集成技术设计ＭＢＩ）的可靠性预计指标，说明数字电路小型化可以使机载电子设备可靠性增长。     

浅谈柔性制造系统的建立

柔性制造系统（ＦＭＳ）是一种高效率、高自动化的产品生产制造系统。本文从市场需求分析着手，叙述了建立ＦＭＳ的步骤、内容，各模块之间的协调以及ＦＭＳ的经济评价；简单介绍了ＦＭＳ在国外的发展状况；展望ＦＭＳ的发展。     

Si3N4—SiC纤维先驱体——低分子量聚硅氮烷的合成与分析

以ＭｅＳｉＣｌ２（式中Ｍｅ代表ＣＨ３）或共混合物与ＮＨ３反应制得低分子量聚硅氮烷，该产物是制备Ｓｉ３Ｎ４－ＳｉＣ纤维先驱体的基本原料。研究了不同配比的Ｍｅ２ＳｉＣｌ２／ＭｅＳｉＨＣｌ２混合物氨解反应所需的时间，氨解产物的物理性能、分子量及其分布，着重要分析了氨解产物的结构。     

MBI软件的标准化及规范化设计

ＭＢＩ作为多路传输总线接口模块，能够实现ＭＩＬ－ＳＴＤ－１５５３Ｂ协议，完成航空电子子系统之间的连接，在通信软件的支持下完成航空电子子系统之间的通信。本文将详细介绍为机载设备ＤＴＳ的ＭＢＩ接口模块配置的通信软件的标准化及规范化设计。     

多总线Ⅱ的通信板

多总线Ⅱ的通信板多总线Ⅱ信板的ＨＣ４８６／ＬＸＸ系列使用４个８ＡＢ８２５２５装置来提供８个通道，每个通道有全双工的ＤＭＡ。使用ＨＤＬＣ协议，ＳＡＢ８２５２５装置执行高这串行通信键。板的线驱动器／接收益定位在拆装的接口模块，该模块由ＰＩ连接器给８个边运...     

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.