网络访问控制技术及其应用分析

从工程应用的角度对网络访问控制（NAC）技术进行总结和分析,对802．1x,TNC,NAP进行了技术框架总结。基于开放性、兼容性、适应性,对以上技术的工程应用进行了分析。802．1x、网关、防火墙、虚拟专用网（VPN）等4种策略执行技术的选择和实现是NAC系统设计的关键。最后总结了NAC选型和设计需要重点关注的内容。     

Pesticides in water and the performance of the liquid-phase microextraction based techniques. A review

The control of pesticides in surface, drinking and groundwater is nowadays a real necessity. In the European Community, their concentration must comply with the established parametric and environmental quality standards (EQSs). Regarding the new legislation, this article updates the information concerning the monitoring of pesticides and the technical specifications for their measurement in water samples where ultra-sensitive analytical methods are required. For some compounds, like pesticides, there is still a need to improve the performance of the existing methods. High sensitive techniques like gas chromatography tandem mass spectrometry (GC–MS/MS) and liquid chromatography coupled with mass spectrometry (LC–MS) have been developed. However, for most of the substances present at trace and ultra-trace levels the extraction and preconcentration steps are so far essential for their detection. Advances at a micro scale have been made and different types of microextractions are being developed. Liquid-phase microextraction (LPME) is an example. The study of this technique has increased in the last years and some innovations have been recently reported for pesticides water analysis. This article reviews the new developed LPME-based techniques and compares its performance with the analytical specifications established for pesticides water monitoring. The results show that LPME-based techniques can be a promising tool to improve the nowadays performance of methods used in pesticides water control.     

互联网密钥交换协议的分析与改进

Internet Key Exchange (IKE) protocols have been becoming an important standard in VPN communications. This paper gives an analysis of identity protection flaw in the main mode of IKE protocols, and then a modification suggestion is proposed to enable IKE supporting Road Warrior users. Denial of Service (DoS) problem that existed in IKE phase I is also discussed and some suggestions are given.     

Cathodic protection of ships in brackish water

The operation of ice-going vessels depends on the condition of the hull surface. Corrosion increases the roughness of ship hull, which increases drag and fuel consumption. The hull surface smoothness is maintained by using coatings and cathodic protection. The cold brackish water is different from ocean water as it has lower salt content, lower conductivity, and higher concentration of dissolved oxygen. These factors mean that the design of the cathodic protection system for ship hulls requires different design values, such as protection current density and protected length, than those given in cathodic protection standards. In this paper, we have estimated the protection current density with polarization curves and the protected length by using Wagner number and dimension and conductivity scaling. In brackish water the protection current density was two times that in ocean water. The protected length in brackish water varied between 10 and 15% of that in ocean water. In poorly conducting brackish water, the current capacity of a cathodic protection system is used mostly for overcoming the solution resistance, not for delivering protection current.     

静电放电模型及其失效特征

本文介绍了人体模型、机器模型和带电器件模型等三种静电放电模型及其模拟测试方法,重点对这三种静电放电模型的失效特征进行了对比分析.对这些失效特征的深入了解,有助于工程师在失效分析时能够判断出静电放电的类型,从而更有效地帮助调查静电放电的根源.     

氮气保护对无铅再流焊焊点外观质量的影响

由于无铅钎料润湿性较差,在实际生产中普遍采用氮气保护。通过新制定的氮气保护无铅再流焊工艺,对焊点外观质量进行了统计分析。其结果显示氮气保护可以减少元件偏移和桥连等缺陷,对竖碑、焊球和锡珠等缺陷也有一定影响。     

Mild and facile procedure for clay-catalyzed acetonide protection and deprotection of N(Boc)-amino alcohols and protection of 1,2-diols

The application of clay as a catalyst for acetonide protection of N(Boc)-amino alcohols and 1,2-diols to obtain good to excellent yields of the acetonide derivatives is described. Acetonide deprotection to obtain the parent amino alcohol was carried out using a similar catalyst in the presence of methanol as solvent. The reaction takes place at room temperature within 2 h to give the parent amino alcohol in quantitative yield keeping the N(Boc) group intact.     

数字式光纤纵差保护的研究

本文叙述了一种新型的利用光纤传输技术和微型计算机技术的全数字式光纤纵差保护装置,它是由华中理工大学和武汉邮电科学研究院激光通信研究所联合研制的,适用于短距离输电线路及其由短线路组成的环网。主要介绍了这套保护装置的原理和构成,针对短线纵差保护中的实际问题,提出了新的解决方案。     

SDH传输网络的保护及其应用

本文讨论了ＳＤＨ网络结构和保护方式，并着重分析ＴＳＤＨ自愈环的保护及其应用。     

探索个人数据保护的中国方案

制定个人信息保护法需要平衡数据创新应用与个人利益保护两种利益。这两种利益并非二元对立、非此即彼,从长远来看,个人信息保护法的制定能够为数字经济产业的健康发展带来充分利好。制定个人信息保护法的工作应以我国实际国情和现有法律制度为基础,以落实个人权利保护与促进数字经济发展为目标,通过进一步完善个人信息定义、明确个人信息处理的合法性基础等方式,勾勒中国方案,贡献中国智慧。