钢／铝合金液固相复合工艺的研究

通过正交试验研究了各工艺量数以钢／铝合金液固相复合性能的影响，最佳工艺条件为铝合金液体温度７９０℃，钢板表面处理为酸洗＋钢刷＋５％的氟钛酸钾助焊剂，复合压力为３９．２ＭＰａ，组织观察表面界面脆性化合物的形成是导致结合强度降低的一个重要因素。     

基于物元分析和层次分析的选厂综合性能评估

利用物元分析法和层次分析法的特点，将物元分析和层次分析法有机的结合起来建立选厂性能综合评估模型，建立的评估模型表明该评估方法能够克服传统方法中参评人员的主观不确定性和认识上的模糊性，可用于选厂有关指标的综合评估。     

PRO——一种新的地震资料处理方法

PRO(影像的参数展开)技术是由俄罗斯地球物理学家开发的一种崭新的地震资料处理技术。本文从PRO基本原理入手,简单介绍了PRO的速度分析原理。PRO速度分析和成像均以信号的椭圆展开和参数展开为基础,其中参数展开方法考虑波型转换、介质的横向不均匀造成传播速度的变化。该技术抛开了传统共中心点叠加的思想,从根本上解决了以CMP方法为基础的传统地震处理技术遇到的困难。通过模型与实例分析对比,PRO比传统CMP方法更优越。     

光盘用光学头物镜性能的综合评估

论述了采用波象差均方根、点扩展函数、光学传递函数对高次旋转对称非球面光学头物镜性能进行综合评估的方法。作者在正则坐标理论基础〔１〕上编制了光学头物镜性能综合评估软件。给出了评估实例。     

Datacryptor~64E剖析

Datacryptor 64E是数据包端一端保密机,用于保护经公用和专用X.25包交换网传输的敏感而有价值的信息。在传输之前先将数据加密,加密后的数据经网络传输,在其终点予以解密。 Datacryptor 64E仅对包的数据字段加密,地址和控制信息仍为明文,以保证数据包正确地通过网的路由传输。既然本设备用于端一端加密,这就意味着它仅安装在网络的终点处,而不是安装在每个网络的链路上。     

Algebraic properties of cryptosystem PGM

In the late 1970s Magliveras invented a private-key cryptographic system calledPermutation Group Mappings (PGM). PGM is based on the prolific existence of certain kinds of factorization sets, calledlogarithmic signatures, for finite permutation groups. PGM is an endomorphic system with message space ℤ_|G| for a given finite permutation groupG. In this paper we prove several algebraic properties of PGM. We show that the set of PGM transformations ℐ _G is not closed under functional composition and hence not a group. This set is 2-transitive on ℤ_|G| if the underlying groupG is not hamiltonian and not abelian. Moreover, if the order ofG is not a power of 2, then the set of transformations contains an odd permutation. An important consequence of these results is that the group generated by the set of transformations is nearly always the symmetric group ℒ_|G|. Thus, allowing multiple encryption, any permutation of the message space is attainable. This property is one of the strongest security conditions that can be offered by a private-key encryption system. S. S. Magliveras was supported in part by NSF/NSA Grant Number MDA904-82-H0001, by U.S. West Communications, and by the Center for Communication and Information Science of the University of Nebraska.     

三相四线统一电能质量调节器的控制策略

针对电网输入电压的不平衡、非正弦及负载的不平衡、非线性特性，提出了一种基于三相静止坐标系下的三相四线统一电能质量调节器（UPQC）的协调控制策略。该策略将UPQC的串联变流器控制为基波正弦电流源，而并联变流器控制为基波正弦电压源，从而实现了三相四线UPQC对电能质量的综合控制能力，既改善了电网侧的电能质量问题，实现了电网输入电流的正弦及单位输入功率因数，也改善了负载侧的电能质量问题，实现了负载电压的平衡、额定及正弦。10 kVA系统实验装置的实验结果表明了该控制策略的有效性。     

迫零对Turbo码的性能影响

从距离谱的角度对迫零在Turbo码中的作用进行了理论分析。通过仿真，研究了迫零对Turbo码性能的影响。仿真结果表明，Turbo码编码器迫零处理有助于改善Turbo码的性能。     

宽带接入服务器的选择配置和应用

本文主要分析了影响宽带接入服务器性能的各种因素，介绍了如何选择宽带接入服务器，并针对REDBACK公司的SMS1800和UNISPHERE公司的ERX1400两种典型宽带接入服务器说明如何进行配置，为应用宽带接入服务器提供参考。     

Hankel transform-domain analysis of scattered fields in multilayer planar waveguides and lasers with circular gratings

Radiation patterns of scattered fields with arbitrary azimuthal orders in multilayer planar waveguides and laser cavities with circularly symmetric gratings are formulated based on the volume current method. Full-wave Green's function analysis based on the integral transform method lies at the heart of this approach. Unlike the conventional approach, the dyadic Green's function relates some auxiliary fields to some auxiliary sources in the spectral domain. These auxiliary functions are defined to facilitate the spectral domain formulation in the cylindrical coordinate system and the use of transfer matrix method for obtaining a closed-form solution of the spectral Green's function in multilayer planar structures. More importantly, it is shown that the far-field pattern of the scattered field can be expressed directly in terms of the auxiliary fields in the Hankel transform domain.