我国软件产业发展需要大举措

目前我国软件产业规模小、人员分散、抗风险能力低下，处于发展的初级阶段，但人才优势与发展册时并存。面对挑战，必须有相应的大举措，如联合、重组、兼并，如多方筹资、加大投入，如强化管理、政策扶植等等，最终做出正确选择。     

逆合成孔径雷达图象的旁瓣清除技术

本文基于逆合成孔径雷达的原理,提出了新的图象旁瓣清除方法,设计了新的门限判别准则,并成功实现了模型飞机的成像。     

用于锁模光纤激光陀螺的相敏检测

通过采用锁相放大器,演示了一种性能明显提高的锁模光纤激光陀螺.结果表明锁相放大器的输出与转动速率之间具有理想的线性关系,并对两脉冲(在时间间隔测量过程中引起相位误差)之间的光强差不敏感.与以往报道的时间间隔测量相比,演示了长期稳定性提高了二个数量级.     

无线Ad-Hoc网络

无线Ad—Hoc网络是由一组自主的无线节点或终端相互合作而形成的、独立于固定基础设施并且采用分布式管理的网络，具有自主性、无严格的控制中心、动态拓扑等特点。路由技术、安全问题和QoS等是目前无线Ad—Hoc网络发展中的关键。尽管无线Ad—Hoc网络具有带宽受限等缺点。由于具备灵活机动、组网迅速的优势．尤其适用于野战军用通信．目前它在民用领域的应用也在逐步扩大。     

MODELING OF INTEGRATED MANUFACTURING SYSTEMS USING AN OBJECT-ORIENTED APPROACH

Traditional approaches to the modeling of complex manufacturing systems are expensive, time consuming, and of limited value. Recent developments in several areas (i.e., knowledge engineering, software engineering, modeling formalisms, engineering workstations, and database systems) are now to the point that a meaningful convergence can be crafted to yield a modeling environment far superior to any we have known in the past. Fundamental to this new approach to modeling are the recent developments in object-oriented programming and related technologies. A research team at Oklahoma State University has been exploring alternative approaches to the modeling and simulation of complex manufacturing systems since 1985. This paper argues for a fundamental paradigm shift in the development and utilization of models within a CEM framework.     

Interface microstructures in the diffusion bonding of a titanium alloy Ti 6242 to an INCONEL 625

A Ti6242 alloy has been diffusion bonded to a superalloy INCONEL 625. The microstructures of the as-processed products have been analyzed using optical metallography, scanning electron microscope (SEM), and scanning transmission electron microscope (STEM) techniques. The interdiffusion of the different elements through the interface has been determined using energy-dispersive spectroscopy (EDS) microanalysis in both a SEM and a STEM. Several regions around the original interface have been observed. Starting from the superalloy INCONEL 625, first a sigma phase (Cr₄Ni₃Mo₂), followed by several phases like NbNi₃, Ŋ/Ni₃Ti, Cr(20 pct Mo), β Cr₂Ti, NiTi, TiO, TiNi, and Ti₂Ni intermetallics, just before the Ti6242 have been identified. Because the diffusion of Ni in Ti is faster than the diffusion of Ti in the superalloy, a Kirkendall effect was produced. The sequence of formation of the different phases were in agreement with the ternary Ti-Cr-Ni diagram.     

Continuous cooling deformation testing of steels

In the processing of steel, the design of any kind of heat treatment and/or thermomechanical processing schedule, to obtain a given microstructure, is greatly facilitated by the knowledge of the austenite-to-ferrite transformation characteristics. In the past, isothermal and continuous cooling tests were used in the laboratory to create time-temperature-transformation and continuous cooling transformation diagrams, respectively, which then served as the source of transformation data. The problem with such information is that it is only truly applicable to one particular microstructure, usually one resulting from a simple reheating cycle in the austenite region. Most industrial steel processing operations additionally involve several stages of high-temperature deformation leading to changes in the microstructure emerging from the final pass. To account for this situation, a novel laboratory method for the determination of the transformation characteristics, based on continuous cooling deformation testing, was developed. A major attraction of this test technique is that the specific microstructure, for which the transformation characteristics are required, can be generated by hot deformation and then immediately evaluated by continuous cooling deformation. In this article, the basic continuous cooling deformation test technique and general methods of data analysis are illustrated, using results from several different grades of steel. Formerly with the Department of Mining and Metallurgical Engineering, McGill University     

Analysis of the laser-cladding process for stellite on steel

Laser-cladding experiments have been performed with STELLITE 6 powder on mild steel substrates, using a 1.5 kW linearly polarized continuous wave CO₂ laser as a heat source. The clad height, the mass efficiency, the dimensions of the melt pool, as well as the global absorptivity, were measured as functions of the powder feed rate and the scanning speed. A quantitative analytical model of the process is proposed, based on the overall mass and energy balance. It allows the calculation of the mass efficiency and of the global absorptivity, taking into account the incorporation of the powder into the melt pool as well as the energy absorbed by the powder jet and the substrate. It successfully explains the experimental results and demonstrates the role played by the melt pool inclination with respect to the substrate. A processing diagram is given to find rapidly the optimal laser treatment conditions and the desired clad height. It is discussed with respect to the other limiting conditions of the process, the geometrical maximum powder efficiency, the porosity, the dilution, and the maximum power of the laser installation.