Internet上电子邮件的安全机制

近年来，Internet用户已不满足于简单电子邮件．要求提供多用途的和安全的电子邮件，为此出现了MIME，PEM，PGP和MOSS，S/MIME，PGP／MIMF，MIMEWithMSP等多种方案、本文综述了这些方案，尤其对安全机制进行了详细的讨论。     

利用公有云对无人值守台站进行数据传输和远程监控的研究

目前黑龙江省地震无人值守台站出于安全考虑已经全部实行内网和外网分开,在这种情况下很多自行开发的应用设备中的数据传输以及远程监控功能就无法实现,为解决这个问题文章通过以黑龙江地震台今年开发的专门为无人台站使用的室内温度加热远程云端温控系统为实例,来探讨如何使用可编程序控制器和工业智能网关利用公有云无线传输数据和指令,并且通过个人计算机以及手机作为智能终端进行远程监控。     

SVD algorithms to approximate spectra of dynamical systems

In this work we consider algorithms based on the singular value decomposition (SVD) to approximate Lyapunov and exponential dichotomy spectra of dynamical systems. We review existing contributions, and propose new algorithms of the continuous SVD method. We present implementation details for the continuous SVD method, and illustrate on several examples the behavior of continuous (and also discrete) SVD method. This paper is the companion paper of [L. Dieci, C. Elia, The singular value decomposition to approximate spectra of dynamical systems. Theoretical aspects, J. Diff. Equat., in press].     

Microstructure, permeability and rheological behavior of lost foam refractory coatings

The effect of microstructure on rheology and permeability of three commercial lost foam refractory coatings available on the market called samples I, II, and III, respectively was investigated in this study. Thermal gravimetric/differential thermal analysis (TG/DTA) method was used for detailed analysis of the organic components and to determine the thermal stability of the coatings. Particle shape and size and particle size distribution (PSD) were obtained by optical microscopy and morphological studies were carried out by scanning electron microscopy (SEM). Also the scanning electron microscopy energy dispersive X-ray analysis (SEM/EDXA) technique was used for elemental analysis of refractory particles. To determine the crystalline structure of the samples, X-ray diffraction (XRD) analysis was carried out. Permeability measurements were conducted with a modified apparatus originally used for determining the permeability of casting sand. Finally the rheological behavior of the samples was investigated using a rotating coaxial rheometer to provide the flow curve for coating suspensions. The studies revealed that coating I has the highest permeability, which can be due to its large mean particle size and wide particle size distribution (PSD). Furthermore it was found that the investigated refractory coatings behave as non-Newtonian fluids with shear thinning behavior. All coatings exhibited yield stresses, indicate that they behave as Bingham-type pseudoplastic fluids.     

一种基于IDEA的十进制短分组加密算法

IDEA是一个著名的加密算法,被广泛应用于各种领域,最著名的有PGP。基于IDEA算法,提出了一种新颖的十进制短分组加密技术。针对十进制数运算的特点,在加密算法中定义了三种新的运算,并从理论上证明新的运算能保证十进制加密算法的可逆性。将该算法应用于短分组加密仿真系统中的结果表明,算法具有良好的密码学特性,加解密的各项扩散率指标均达到很好的效果,其中1轮加密过程过后明文对密文的扩散率就达到了完全扩散。该加密算法可广泛用于各种需要十进制数加密的领域。     

IDEA加密标准在开发系统时的一些改进

分析介绍了IDEA国际数据加密标准,提出了解决明文最后一个不完整分组的新方法(适用于其他分组加密算法),简化了用户密钥管理(适用于所有加密算法),并在其他方面也提出了有实际意义的处理方法。     

C3I系统信息加密技术研究

对C^3I系统的信息安全性进行了分析,讨论了安全体系结构及数据保密的实现途径,建立了C^3I系统的安全模型,综合使用IDEA类算法、RSA相关算法、HAVAL杂凑算法设计了一个C^3I数据加密系统。     

Approximation by fat arcs and fat biarcs

A general discussion of the including approximation of a curve by a fat arc is given followed by an algorithm for constructing an including fat arc for a parametric Bézier curve. An example of applying the algorithm is given. The results for a fat arc are then used to develop an including approximation for a curve segment using a fat biarc. An algorithm for a fat biarc including approximation is provided followed by examples of Bézier curves being included by a fat biarc.     

D07系列质量流量控制器毛细管堵塞的处理方法

D07系列质量流量控制器被广泛的应用到电子、化工、石油、医药、环保等领域的科研和生产中,当其出现故障时我们要有一个好的解决方法,确保生产正常。