PKI/CA技术综述

公开密钥基础设施(PKI)是解决网络安全的技术．典型PKI应用系统包括安全Web、注册机构(RA)、认证机构(CA)、目录(LDAP)和数据库等服务器．RA验证客户证书申请后提交CA．CA检查信息完整和数字签名正确后把证书存放到证书库和目录服务器，并将签发证书序列号通知客户和RA．客户即可使用该号通过目录服务器下载证书．1993年以来，美、加、欧洲、韩、日等国已相继展开PKI研究．我国2001年将PKI列入十五863计划，并着手解决PKI标准化、CA互联互通等关键技术问题。     

基于CPX8216硬件平台的GPRS板间切换的实现

GPRS全称通用分组无线业务,它在改进了现有GSM系统后能实现高速的数据传输。首先对GPRS系统做了简单介绍,然后在此基础上详细介绍了GPRS的板间切换在CPX8216硬件平台上的实现方法。     

微合金元素Cu及等温温度对低碳硅锰钢氢扩散行为的影响

目的探究微合金及热处理工艺对氢扩散的影响。方法设计含0.4%Cu及未含Cu的两种低合金钢,采用两相区保温-淬火-配分(IQP)热处理工艺获得280、400℃等温温度的试验钢,通过SEM、EBSD、电化学氢渗透等方法分析其氢扩散行为。结果对于无Cu钢,当等温温度为280℃时,大角度晶界占比55%,残余奥氏体(RA)体积分数约为0.02%,氢扩散系数约为1.82×10-7cm2/s;当等温温度为400℃时,大角度晶界占比51%,RA体积分数约为0.35%,氢扩散系数约为1.30×10-7 cm2/s。对于含0.4%Cu的低合金钢,等温温度为280℃时,大角度晶界占比46%,RA体积分数约为0.15%,氢扩散系数约为2.70×10-7 cm2/s;贝氏体区等温温度为400℃时,大角度晶界占比33%,RA体积分数约为3.00%,氢扩散系数约为0.40×10-7 cm2/s。结论微合金元素Cu的添加,导致晶粒度的细化,大角度晶界占比更低,RA含量更高,从而其氢扩散系数更低,不利于氢扩散行为的发生。当等温温度由280℃升到400℃时,虽然会导致晶粒粗化,但大角度晶界占比更低,且RA含量更高,同样会降低其氢扩散系数,不利于氢扩散行为的发生。由此可知,含0.4%Cu、等温温度为400℃时,IQP钢的氢扩散能力最差。     

基于C/S和B/S混合结构的形象化工程进度控制系统

介绍了在铁路建设工程的项目管理中,基于异地协同工作环境下,面向业主的形象进度控制系统的结构与功能模块的设计、实现方法,并对其中用到的关键技术作了简要说明。     

电子商务CA认证系统方案研究

介绍了电子商务安全管理方面广泛使用的CA认证技术,详细阐述了当今CA认证系统的主要体系和系统网络框架。     

A Longitudinal Examination of Causal Attributions and Depression Symptomatology in Rheumatoid Arthritis.

Objective: Examine longitudinal relationships between causal attributions and depression symptoms in adults with rheumatoid arthritis (RA). Study Design: Cross-lagged panel correlations tested the temporal precedence of attributions relative to depression symptoms over 1 year. Participants: Forty-two participants completed self-report instruments on 2 occasions. Main Outcome Measures: The Inventory to Diagnose Depression and the Attributional Style Questionnaire. Results: Time 1 attributions predicted increased levels of depression symptoms at Time 2 after perceived pain and disability were controlled: Time 1 depression symptoms were unrelated to Time 2 attributions. Cross-lagged correlation comparisons revealed statistical dominance for attribution-depression relationships relative to depression-attribution relationships. Conclusions: Results support cognitive diathesis conceptualizations of depression and support cognitive-behavioral treatments for depression in RA. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Profibus-DP在直流调速器6RA70的应用

本文简述了Profibus-DP总线技术和SIMOREGDC-MASTER的特点,构造出由直流调速器6RA70、S7-300PLC和WinCC组成的基于Profibus-DP总线的控制系统,并介绍了该系统的特点及该系统中的PLC与直流调速器6RA70之间的参数设置和编程过程。     

Experimental investigation on high temperature wettability and structural behaviour of SAW fluxes using MgO–TiO2–SiO2 and Al2O3–MgO–SiO2 flux system

To establish the relationship between wettability and structure with the change in SAW flux composition, the contact angle measurement study was performed at 1700 K. For MgO–TiO₂–SiO₂ and Al₂O₃–MgO–SiO₂ flux system the wetting behaviour was studied by evaluating the contact angle as well as surface tension properties. Sessile drop method was used to determine the wetting properties of SAW fluxes. Twenty-one SAW fluxes were designed & developed by applying mixture design approach of design of experiments. Chemical, phase and structural properties of SAW fluxes were measured using modern techniques such as X-ray fluorescence (XRF), X-ray diffraction (XRD) & Fourier Transform Infra-red spectroscopy (FTIR). As per the calculated contact angle value, different surface tension values for MgO–TiO₂–SiO₂ and Al₂O₃–MgO–SiO₂ flux system was calculated using Young's & Boni's equations. Using Dupre's equation the adhesion energy for twenty-one basic fluxes was also calculated. Measured contact angle value increased with increase in the TiO₂/MgO & TiO₂/Al₂O₃ flux ratio. Lower contact angle gives higher wettability between the flux and the heating substrate. With increase of TiO₂/SiO₂ ratio up to 1.5 to 2.0 the calculated surface tension value is decreasing while after that it is increased with increase in TiO₂/SiO₂ ratio.     

PPP项目风险分担研究评述

通过整理和分析大量文献,界定风险分担的概念并对该领城研究进行详细的归类阐释,从中提炼出PPP项目风险分担的三种基本研究路径:理论推演、理论应用和实践总结,得出PPP项目风险分担研究具有三个薄弱环节,即风险分担的过程评价、风险分担比例的确定以及风险分担与其他方面的关联关系,从而指出该领城未来的研究方向.     

UEs Power Reduction Evolution with Adaptive Mechanism over LTE Wireless Networks

At present, the major drawback for mobile phones is the issue of power consumption. As one of the alternatives to decrease the power consumption of standard, power-hungry location-based services usually require the knowledge of how individual phone features consume power. A typical phone feature is that the applications related to multimedia streaming utilize more power while receiving, processing, and displaying the multimedia contents, thus contributing to the increased power consumption. There is a growing concern that current battery modules have limited capability in fulfilling the long-term energy need for the progress on the mobile phone because of increasing power consumption during multimedia streaming processes. Considering this, in this paper, we provide an offline meaning sleep-mode method to compute the minimum power consumption comparing with the power-on solution to save power by implementing energy rate adaptation (RA) mechanism based on mobile excess energy level purpose to save battery power use. Our simulation results show that our RA method preserves efficient power while achieving better throughput compared with the mechanism without rate adaptation (WRA).