A Study of the Compatibility Between Asphalt and SBS

In this article, the compatibilities between different components of a base asphalt and styrene butadiene styrene (SBS) have been analyzed from microscopic structures. Specifically, the asphalt was separated into three components: saturates, aromatics, and resins, by Solvent Recycled Absorption Chromatography Separation Technology (SRACST). The compatibilities between these different components and the polymer were compared with the help of Fluorescence Microscope (FM) with which the existing state of the polymer SBS in these different components could be examined obviously. The modified effects indicated that aromatics could cause SBS swollen and, resins dissolved SBS better than saturates, though both the two components could partially dissolve SBS and the two mixtures presented two immiscible phase systems. In order to further investigate the compatibility between aromatics and SBS, from macroscopic properties, an additive rich in aromatics was added to the SBS/asphalt mixture, and the result was satisfactory.     

Chosen plaintext attack on a cryptosystem with discretized skew tent map

An encryption system with discretized skew tent map has been proposed recently by N. Masuda . However, there is a fundamental weakness with this chaotic cryptographic scheme. In this paper, a chosen plaintext attack requiring only two plaintexts is proposed. An improved version of this attack that narrows the key space need to be searched is also suggested. The test results demonstrate that this encryption cryptosystem is easily broken under the proposed chosen plaintext attack.     

用通用DSP实现话带MODEM

概述了设计话带ＭＯＤＥＭ时所要考虑的基本问题。介绍了一种用通用ＤＳＰ设计的ＭＯＤＥＭ，并讨论了相应的控制程序和调制，解调程序的设计方法和结构框图，而且设计了一个简单实用的握手协议。最后，进一步分析了这种ＭＯＤＥＭ的特点和它的应用前景。     

四坐标数控加工原理及算法研究

本文对四坐标数控加工原理和算法作了详细介绍，尤其对四坐标加工的刀轴矢量算法进行了研究，提出了用垂直于回转轴的平面与刀具运动方向和前导角形成的圆锥面求交，生成刀轴矢量的方法，该方法具有立意新颖、思路清晰，性能可靠，易于在微机上实现等特点，对复杂曲面零件的加工编程，具有重要的实用价值。     

Robust control of nonlinear uncertain systems without generalizedmatching conditions

A novel procedure, called recursive-interlacing procedure, is proposed for designing globally stabilizing robust control. The procedure introduces new interlacing steps and combines them with the existing recursive or backstepping design. It is shown by examining all possible third-order vector systems that the procedure is applicable to systems not satisfying any of the existing structural conditions, that is, to systems in which uncertainties are potentially anywhere and of any bounding function. By its nature, the procedure is not limited to systems of any specific order; it either produces stabilizing control or reveals certain measure of unstabilizability, and it includes recursive design as a special case     

星载成形反射面天线的设计方法

成形反射面天线的设计与综合是近年来卫星天线发展的一个热点问题 ,本文对日本、北美和欧洲成形反射面天线的技术发展和综合方法作了介绍和比较。     

机载雷达空时二维信号处理自适应权值训练的距离分段递推算法

本文针对机载预警雷达的杂波环境，分析了杂波数据的非平稳性，由此提出在距离上分段实现空时二维自适应处理（STAP）的方法，并通过分析杂波于空间的距离来确定分段的方法。在同时考虑实时性和处理器性能的前提下，给出了一种自适应权值计算的递推算法。理论分析和计算机仿真结果均表明，本文提出的分段递推算法是有效的。     

木寡糖的研究进展

木寡糖可以从多种多样含木聚糖的原材料中通过化学法或酶法制得，然后再利用物理化学方法精制。作为食物配料，木寡糖具有许多有利的技术特性，并且具有调节肠功能的能力，能导致生物前效应。除了对肠功能的作用外，其他关于木寡糖的生物活性也作了相关综述，包括木寡糖在生物合成配置方面的作用以及他们的技术特性和市场前景。