采暖期燃煤排放对四平市空气质量的影响分析

文章于2014年4月1日~4月30日在吉林师范大学对大气污染物PM10、NOX和SO2进行监测。采暖期,PM10、NOx和SO2的浓度分别为150.9μg/m3、46.4μg/m3和27.3μg/m3,虽没有超过空气质量标准,但是其数值都比非采暖期高。采暖期PM10浓度为非采暖期的1.6倍,NOx和SO2的浓度分别为非采暖期的1.3倍和1.8倍。无论是采暖期还是非采暖期,AQI指数与PM10浓度呈强相关性,说明PM10为四平市首要大气污染物。     

PKI/PMI联合认证和授权在联网审计系统中的应用

联网审计是网络经济发展对审计的必然要求,是电子政务的重要组成部分,建立PKI/PMI联合认证和授权子系统,保障审计业务信息的安全性十分必要.笔者设计了联网审计系统的PKI/PMI的联合身份认证和权限验证子系统,实现对联网审计系统用户的身份认证和权限验证,是联网审计安全体系的重要组成部分.主要介绍了联网审计PKI/PMI联合认证授权系统的功能和结构,给出了该系统的实现过程及其在审计数据安全传输中的应用.     

Experimental study on fatigue failure and damage of sandwich structure with PMI foam core

Sandwich structures consisting of aluminium skin sheets and polymethacrylimide foam core have been gradually used in the high‐speed trains. The static mechanical properties and fatigue damage of the sandwich structures with polymethacrylimide foam core were experimented in three‐point bending and were discussed. The failure mode is identified as local indentation. The static strength was obtained, and it showed good consistency with the forecasting formula. The fatigue property and damage evolution were also researched under cyclic loading. The fatigue life curve and the fitting formula were submitted. The fatigue damage evolution started from the skin sheet fracture and then the foam core indentation. The displacement at the midpoint as the damage parameter was discussed, and the evolution prediction formula was submitted, which showed great agreement with the experimental results.     

吸波性PMI泡沫塑料的制备及性能研究

通过增粘和分散技术将吸波剂导电碳黑引入到聚甲基丙烯酰亚胺(PMI)泡沫塑料中,制备出了具有一定吸波性能的PMI泡沫塑料。实验发现,采用高速剪切和高功率超声波的复合分散法可将吸波剂导电碳黑均匀分散至增粘后的单体混合液中,且增粘剂和吸波剂对聚合与发泡过程无不良影响。结果表明,随着导电碳黑用量增加以及试样厚度的增加,PMI泡沫塑料的吸波性能显著提高。由于采用了增粘树脂,同密度吸波性PMI泡沫塑料的压缩性能下降。     

基于SAML和PMI的授权管理模型

针对跨应用系统交互过程中存在的安全认证问题,提出了一种基于安全断言标记语言(SAML)和授权管理基础设施(PMI)的授权管理模型。该模型运用逻辑分离和应用结合的方法实现用户权限管理和授权访问。在PMI的基础上运用SAML断言、SAML协议和SAML绑定技术实现身份验证、属性获取和授权决策,通过属性权威机构(AA)和目录服务器(LDAP)实现对证书的管理。实验结果表明,该模型能有效实现对多角色用户的跨应用系统安全访问控制。     

基于属性证书的移动代理访问控制解决方案

分析了移动代理系统的特点,针对移动代理系统的安全需求尤其是访问控制问题,以PKI/PMI做基础服务设施,对应于移动代理和代理平台,引入了代理属性证书和平台属性证书,以扩充移动代理系统处理环境.应用Java虚拟机(JVM)的类动态装载技术和方法调用所提供的简单且有效的方式来支持代理平台的扩展,使该文案具有足够的灵活性,包含的安全策略,适合于大多数基于移动代理的应用.     

Research on System of Enterprises' Information Management Based on Attribute Certificate

In order to accommodate the complex network data of large scale companies,this thesis analyses PMI,strategy and role hierar-chical model.On such a basis,the thesis proposes an applicable plan for access control of enterprises’ information system based on attribute certificate.     

A Secure Access Control Mechanism Web Service-based in, Extended Organization PKI Networks

Organizations use PKI （Public Key Infrastructures） to support internal business processes, but some businesses have industrial partnerships with others, and these alliances can exploit B2B （Business to Business） e-commerce capabilities by connecting corporate PKI. The paper deals with two methods to realize access control in extended organization PKI business processes： BCAs （Bridge Certification Authority） create a combined multi-enterprise PKI at the cast of increased complexity when evaluating the acceptability of certificates. But today＇s COTS （Commercial Off-The-Shelf） products are not entirely prepared to meet the challenges of bridge-connected PKIs. The paper focuses on designing a secure access control mechanism in extended organization PKI networks based on web service. The secure access control mechanism has integrated the role-based access control in X.509v4 PMI （Privilege Management Infrastructure） with the XML （Extensible Markup Language） securily solution. The paper proposes the access control mechanism and realization technology in details, and some measures to improve the system＇s running efficiency are suggested.     

电子政务系统属性证书交换模型研究实现

本文分析了特权管理基础设施PMI以及其属性证书在电子政务系统中应用的必要性和可能性，在充分研究电子政务属性证书的两种交换模式的基础上，结合我国电子政务网络特征，分别建立了适合电子政务内网和外网的属性证书交换模型，并与PERMIS和Akenti进行了比较分析。     

聚甲基丙烯酰亚胺(PMI)泡沫的进展

聚甲基丙烯酰亚胺(Polymethacrylimide,PMI)泡沫是当今夹层结构复合材料最主要的芯材,具有密度低、力学性能和耐热性能突出、易于机加工、与热固性树脂黏结良好、适应于热压罐固化工艺等突出优点,已经在航空航天、交通运输、风电叶片、医疗器械、电子通讯等领域获得较广泛应用。本文对PMI泡沫的发展历史、制备技术、结构与性能进行了综述,并提出了国内PMI泡沫进一步发展亟待解决的问题。