网络安全评估方法分析

近年来,网络攻击事件时有发生,给社会和企业带来巨大威胁和损失,对于网络安全评估方法的研究成为了热点,文中介绍了网络安全评估方法的研究现状,分析了网络安全评估相关技术,进而探析了网络安全评估方法。     

UPnP基本原理以及在NAT中的应用

在互联网应用越来越丰富的情况下,设备之间如何通过UPn P方案实现互联互通显得日益重要,本文介绍了UPn P所定义的基本协议（如SSDP、GENA、SOAP等）,重点分析了UPn P实现的基本工作流程,并通过抓包工具捕获数据包,对各种流程传递的协议报文进行详尽分析,最后结合NAT技术,重点叙述UPn P在NAT技术中的应用。通过本文能够加深认识设备之间互联互通的一种方案。     

DES_RSA及其混合算法的加密速度研究

为了在保证安全性的前提下提高大量数据加密的加密速度,本文通过DES和RSA算法的分析,针对DES算法密钥安全性差和RSA算法加密速度慢的问题,提出DES和RSA混合算法.对比DES和RSA两种算法加密所需时间,就RSA算法耗时长的问题,通过几种可行的大素数判定算法分析,提出改进的大素数判定算法.在保证安全性的前提下,将改进的大素数判定算法应用于RSA算法中,提升了加密速度.由于改进算法加密速度仍远差于DES算法,不适合大量数据加密.因此在兼顾安全性与加密速度的基础上,提出DES和RSA混合加密算法.经分析该算法综合了前两种算法的优点,是一种理想的加密算法.     

Response surface methodology study on electrochemical adsorption regeneration of water-based drilling fluid waste

ABSTRACT

This study explores an electrochemical adsorption method on the regeneration of aqueous drilling fluid waste. Response surface analysis was applied to investigating the electrochemical factors on the adsorption performance. The response surface polynomial model optimized the preferred electrochemical adsorption conditions with adsorption time of 20 min, spacing electrodes of 5 cm, adsorption concentration of 5% and NaCl concentration of 2 g/L. The model calculated electrochemical adsorption amount of drilling fluid showed only 1.3% deviation from the experimental results. Thus, the model could provide effective support for the device design and application of drilling fluid electrochemical adsorption process.     

Low-temperature methanol synthesis in a circulating slurry bubble reactor

A circulating slurry bubble reactor was developed to synthesise methanol via methyl formate from the gas mixture of carbon monoxide and hydrogen at low temperature. The strategy for designing and scaling up the bubble reactor involved a preliminary understanding of fluid dynamics in a cold model, continuous operations under industrial conditions and a parallel experiment in an autoclave. Per-pass syngas conversion was investigated during 100-h operations. The axial profile of solid catalyst concentration was measured just before the shutdown and the composition of liquid product was analysed after the shutdown. These results show that the circulating slurry bubble column will become a potential reactor for the commercial process of low-temperature methanol synthesis after the catalyst system has been improved.     

氨纶氯水降解及耐氯机理的探讨

应用红外光谱分析方法，对氨纶（ＰＵ纤维）氯水降解及耐氯机理进行了初步的研究。结果表明，ＰＵ浸氯水后，因受活性氯原子的攻击，ＰＵ大分子软链段的碳－碳键发生断裂，形成碳－氯化合物，添加剂加入后，因与ＰＵ大分子的软链段形成螯合物，从而避免了活性氯原子的攻击，有效地保护了软链段，使氨纶耐氯性能明显改善。     

Stochastic stability of semi‐Markovian jump systems with mode‐dependent delays

Semi‐Markovian jump systems, due to the relaxed conditions on the stochastic process, and its transition rates are time varying, can be used to describe a larger class of dynamical systems than conventional full Markovian jump systems. In this paper, the problem of stochastic stability for a class of semi‐Markovian systems with mode‐dependent time‐variant delays is investigated. By Lyapunov function approach, together with a piecewise analysis method, a sufficient condition is proposed to guarantee the stochastic stability of the underlying systems. As more time‐delay information is used, our results are much less conservative than some existing ones in literature. Finally, two examples are given to show the effectiveness and advantages of the proposed techniques. Copyright © 2013 John Wiley & Sons, Ltd.     

橡胶模型制品胶坯精密预成型机

介绍了橡胶工业橡制品生产中胶坯制备的三种方法，其中详细介绍了精密预成型机制备胶坯。以上海德仁橡塑机械有限公司物精密预成型机为例，从结构，性能及工艺参数等方面进行了分析，说明精密预成型机是批量生产橡胶模型制品的一种得力辅助设备。     

基于形变模型的多视图三维人脸重建

本文提出了基于形变模型的多视图三维人脸重建方法,将人脸形变模型与同一人脸在不同视点下的多幅图像进行匹配,从而重建出具有较强真实感的三维人脸模型。本文将对基于形变模型的多视图三维人脸重建方法进行详细的阐述,并把实验结果与单视图重建出的三维人脸模型进行了对比,从而体现出多视图重建的优势所在。     

信息技术在数学教学中的应用研究

以多媒体计算机和网络为核心的信息技术在小学数学教学中的运用,使数学教学活动更加丰富多彩,激发学生的学习兴趣,增强学生的主体意识,培养学生的技能,拓展学生探究的时间和空间,引发学生主动、积极、创新的思维,开发学生的智力,促进学生主动学习,主动发展,从而有效地提高课堂教学效率.