从DES算法论分组密码的设计原则

分组密码一直是解决信息系统安全问题的常用技术方法。尽管作为分组密码典型代表的DES算法目前已被更为安全的Rijndael算法取代,但其中所体现的设计思想和设计原则依然值得研究和借鉴。文中以DES加密算法为例,在分析DES加密过程、密钥计算、加密函数和解密过程的基础上,探讨分组密码的设计原则。指出组件结构标准化原则、算法和密钥分离原则、扩散和混淆原则以及均匀性和随机性原则是现代分组密码设计的基本原则。这些原则是现代分组密码设计的出发点。     

Application of the C-Me segregating theory in solid alloys to ceramics

Because of its excellent properties, zirconia ceramics has already been widely applied. Its phase transformation affects its properties. The research on the mechanism of its phase transformation is very important to control the phase transformation as well as its properties. The valence electron structure of cubic zirconia, tetragonal zirconia and monoclinic zirconia are calculated with the em-pirical electron theory in solids and molecules in this paper. The results show that the total numbers of the covalent electron pairs which form their strong bond framework are 3.19184, 3.45528 and 3.79625, respectively. According to the view-point of the C-Me segregating theory in solid alloys, it can be deduced that the phase transformation order of zirconia should be liquid phase→cubic phase→tetragonal phase→monoclinic phase. The deduction from valence electron struc-ture is completely in accordance with the experimental results, so the electron theory of phase transformation in alloys can be expanded to ceramics materials.     

日立Z-5000型原子吸收分光光度计常见故障分析及排除

文章介绍了日立Z-5000型原子吸收分光光度计火焰系统和石墨炉系统在日常分析中出现的故障现象和解决方法。     

气体扩散电极制备条件与氧还原反应活性关系的研究

在改变催化层中聚四氟乙烯(PTFE)、造孔剂含量和热压压力等条件下制备气体扩散电极,通过计时电位法、阴极极化曲线对气体扩散电极进行测定,并将其结果用最小二乘法拟合得出电极的制备条件与氧气还原反应电化学参数之间的关系。电化学测试结果表明,各种条件下制备的电极的阴极极化过程都符合Rho提出的半经验公式规律;当气体扩散电极催化层PTFE面密度3.33 mg/cm2、造孔剂(NH4)HCO3面密度1.05 mg/cm2以及热压压力3.69 MPa时,气体扩散电极的氧还原活性最佳。     

Theoretical analysis of alloy multiplying factor by the empirical electron theory of solids and molecules

By introducing the distribution probability of structural units in austenite containing alloying elements and considering its effects on phase transformation, this paper establishes a calculation model of distribution probability of structural units. A new valence electron structure (VES) parameter-transformation effect coefficient of alloying elements (HL), is defined and then studied both theoretically and experimentally. The relationship between the parameter HL and the multiplying factor (the quenching capability factor) of alloying elements is studied. The results indicate that the two parameters (HL and the quenching capability factor) have the same variation characteristic and substance feature. Therefore, the multiplying factor virtually expresses the relative quantity of structural units in the alloying elements-containing austenite. Supported by the National Natural Science Foundation of China (Grant Nos. 50271009, 503334010)     

挤出中空成型机基础知识与名词介绍(二)

介绍了挤出中空成型机的基础知识和常用名词,以苏州同大机械有限公司的设备为例进行讲述。本文是在《塑料包装》杂志上连载的中空吹塑技术方面的文章,属连载文章的其中之一。     

嘉兴市主城区路桥信息采集与建库

道路、桥梁的空间信息和属性信息,经过外业的采集、调查、成图（AutoCAD）之后,便是这些海量数据的编辑入库工作,本文讲述了嘉兴市主城区范围内的道路、桥梁信息采集的内容,以及相关数据的后期编辑和入库工作。     

一种基于嵌入式Linux图形用户接口的实现

介绍了Java技术在嵌入式L inux图形用户接口(GU I)中的应用,分析了Java GU I的标准窗口构件工具箱(SW T)以及嵌入式L inux GU I的结构和特点。然后实现了一种基于嵌入式L inux GU I系统架构SW T+G tkFB,并作了深入而全面的分析,最后展望了其发展前景。     

Statistical values of valence electron structure parameters applied to research on phase transition temperature and eutectoid reaction of titanium alloy

Based on the empirical electron theory of solids and molecules (EET), the statistical values of valence electron structure parameters Sn _A and SE _A which can characterize the properties of alloy phases are calculated, and influences of alloying elements (e.g., V, Nb, Mo, Hf, Zr, Fe, Mn, Co, Cr, Si, and so on) on the phase transition temperature and eutectoid reaction of titanium alloy are discussed with the statistical values of valence electron structure parameters. The research results agree well with real situations. Supported by the National Natural Science Foundation of China (Grant No. 50471022, 50741004) and National Key Basic Research Program of China (“973”) (Grant No. 2007CB613807)     

牺牲阳极保护法在接地网防腐改造中的应用

分析了接地网在土壤中的腐蚀机理及所造成的危害,介绍了接地网防腐方法的特点和不足,并对牺牲阳极保护方法的原理、腐蚀程度的判断及阳极材料的选择进行了论述。