电致伸缩陶瓷微位移器非线性的数值方法补偿

本文通过对电致伸缩陶瓷材料的非线性进行分析。找到了补偿电致伸缩陶瓷非线性的数值方法，并对不同回程大小的电滞回线进行了分段处理，使补偿结果更为精确。     

GaAs／AlGaAs多量子阱红外探测器的光电流谱

测量了ＧａＡｓ／ＡｌＧａＡｓ多量子阱红外探测器在零偏压、小偏流和大偏压等条件下的光电流谱，并结合理论计算的光跃迁能量讨论了光电流谱的多峰结构和异常增强特性。     

The minimum squared euclidean distance of multi-h phase codes

The minimum squared Euclidean distance(MSED) of binary multi-h phase codes is presented. The signal segregation degree(SSD) has been put forward to determine MSED of multi-h phase codes. In order to maximize MSED, SSD should be as large as possible. The necessary and sufficient conditions of maximizing SSD are derived. Finally, SSD and the exact formulae for MSED of binary 2-h phase codes are also presented.     

多缝式烧嘴点火器在攀钢烧结生产中的应用

多缝式烧嘴点火器具有燃烧效率高，火焰长度易调，炉膛温度分布合理等优点，经工业试验证明，该点火器能满足攀钢烧结点火工艺要求，并有明显节能效果。     

Effect of thermomechanical treatment on mechanical properties and electrical conductivity of a CuCrZr alloy

The CuCrZr alloy undergoes processes of precipitation during ageing. Besides precipitation hardening the strength is affected by cold deformation which is performed before and after ageing. The cold deformation (D ₁) before ageing accelerates the process of strength hardening, since it induces higher rate of precipitation from the saturated a-sold solution. Cold deformation (D ₂) after ageing primarily affects the alloy strength. In this paper the results of the effect of thermomechanical treatment on mechanical properties and electrical conductivity of a CuCrZr alloy are presented. The aim of the paper was to evaluate the most suitable combination of thermomechanical treatment and alloy properties.     

Buckling analysis for delaminated composites using plate bending elements based on higher‐order zig‐zag theory

A finite element based on the efficient higher‐order zig‐zag theory with multiple delaminations is developed. The bending part of the formulation is constructed from the concept of DKQ element. Unlike conventional elements, a developed element has its reference in the bottom surface which simplifies zig‐zag terms on formulation. Exact patch solutions are developed on elements which have the bottom reference system. The present element passes proper bending patch tests in the arbitrary mesh configurations in isotropic materials. Zig‐zag formulation is adopted to model laminated plates with multiple delaminations. To assess the accuracy and efficiency of the present element based on higher‐order zig‐zag theory with multiple delaminations, the linear buckling problem of laminated plates with multiple delaminations has been analysed. The results have been compared with three‐dimensional elasticity solutions. The present element works as an efficient tool for analysing the behaviour of the laminated composites with multiple delaminations. Copyright © 2002 John Wiley & Sons, Ltd.     

Transmit Diversity Schemes for WCDMA

Previous work on transmitter antenna diversity has shown that the use of multiple transmitter antennas at the base station results in improved performance due to increase of diversity (path diversity). This happens with no bandwidth cost, even when the signal quality along several paths is poor, but the receiver estimates the channel with accuracy. This paper evaluates the effects of channel estimation errors in the performance of the schemes designated as Space-Time Transmitter Diversity (STTD) and Selective Transmitter Diversity (STD). We consider low to medium signal to noise ratios characteristic of Wideband Code Division Multiple Access (WCDMA) networks. Different fading channel models are considered for comparison between the two schemes. The improvement due to convolutional coding associated with these techniques is also evaluated.     

两个基于身份的数字签名方案的安全性改进

分析了文献[1]提出的两个基于用户身份的数字签名方案，发现其一般签名方案存在安全性缺陷，在此基础上建立了多重签名方案，但此方案也是不安全的。本文给出了改进的签名和多重签名方案。     

Two- or three-stage least squares?

Two elements enter the choice between 2 and 3SLS for full-system estimation: statistical efficiency and computational cost. 2SLS always has the computational edge, but 3SLS can be more efficient, a relative advantage that increases with the strength of the interrelations among the error terms. A measure of these interrelations is thus helpful in making the choice, and, when there are only two equations, this has suggested using a high pairwise error correlation as an indicator of when to use 3SLS. In larger systems of equations, however, these pairwise correlations can remain small even though more general interrelations give 3SLS the relative advantage. More general indicators are therefore needed, and this paper suggests three such and demonstrates their efficacy.Professor of Economics, Boston College, and Principal Research Associate, Center for Computational Research in Economics and Management Science, MIT. All computation was done on the TROLL system at MIT. My thanks go to Josh Charap for his able research assistance. This research was sponsored in part by the National Science Foundation under grant #IST-8420614.     

多目标决策问题非支配解集的一种序列逼近方法

在多目标优化中,对非支配解集的估计是一项非常重要的工作.本文给出一种序列逼近非支配解集的方法.