回火方式和时间对高速钢的组织与性能的影响

采用透射电镜、X—射线等手段研究了不同回火方式和时间下 W6Mo5Cr4V2高速纲力学性能与组织的变化。发现淬火该钢经560和630℃多次回火后马氏体内孪晶清晰完整,板条马氏体中仍然存在着以魏氏组织形态分布的 M_3C 型碳化物。证实380℃×(0.5～5)h+560℃×1h×2次的低高温配合回火工艺与560℃×1h×3次的普通回火相比,可使高速钢的硬度、红硬性及冲击韧性提高.采用560℃×(1～3)h×3次的回火工艺时,随每次回火时间延长,高速钢的强度、冲击韧性和断裂韧性提高,红硬性变化不大,但硬度则稍稍下降(约1HRC).     

应用功的互等定理法求解弹性中厚板弯曲

本文根据Ｒｅｉｓｓｕｅｒ理论、用功的互等定理法。求解了在均布横向载荷作用下弹性中厚板的弯曲问题．应用本法只需求解一个简单积分方程．就可得到挠曲面方程的精确解．计算表明．这是一种简便有效的方法．     

Fourier级数的Euler平均对有界变差函数的点态逼近

本文估计Ｆｏｕｒｉｅｒ级数的Ｅｕｌｅｒ平均对有界变差函数的点态逼近度。     

DOS攻击原理及对策

随着互连网应用的推广普及,威胁网络可靠运行的安全问题变得极为重要.通过详细研究严重危害网络安全的DOS攻击,提出了预防并消除其破坏的具体方法和措施.     

Mlgebraic Attack on Filter-Combiner Model Keystream Generators

Algebraic attack was applied to attack Filter-Combiner model keystream generators. We proposed thetechnique of function composition to improve the model, and the improved model can resist the algebraic attack. A new criterion for designing Filter-Combiner model was also proposed: the total length L of Linear Finite State Machines used in the model should be large enough and the degree d of Filter-Combiner function should be approximate [L/2].     

An Improved Model of Attack Probability Prediction System

This paper presents a novel probability generation algorithm to predict attacks from an insider who exploits known system vulnerabilities through executing authorized operations. It is different from most intrusion detection systems （IDSs） because these IDSs are inefficient to resolve threat from authorized insiders. To deter cracker activities, this paper introduces an improved structure of augmented attack tree and a notion of ＂minimal attack tree＂, and proposes a new generation algorithm of minimal attack tree. We can provide a quantitative approach to help system administrators make sound decision.     

Improved Authenticated Multi-Key Agreement Protocol

Zhou et al give an attack on Ham＇s modified authenticated multi-key agreement protocol, and give a protocol that can prevent the unknown key-share attack. The paper points out that the protocol is vulnerable to a concatenation attack. This paper proposes an improved authenticated multi-key agreement protocol which shows how to make Harn＇s protocol more secure by modifying the signature and verification. And this protocol can escape the concatenation attack.     

和谐大学师生人际关系的意义与构建研究

和谐,已经成为社会发展的主旋律。和谐校园应是其中的组成部分,而和谐的大学师生人际关系是促成大学校园和谐的有力切入点。人际关系和谐表达了一种心理和谐,这符合和谐社会的最终意义。大学师生人际关系构建的教育学意义的重新诠释及其具体途径探寻,可以作为对这一主题的建设性说明。     

2m次根方案在同步攻击下的安全性证明

证明了在分解整数困难的前提下，2^m次根方案在同步攻击下是安全的.     

基于缓冲区溢出的网络渗透技术的实现

作为信息安全防御技术的对立面，网络渗透技术在信息安全领域里扮演着重要的角色.缓冲区溢出技术是网络渗透最基本的技术之一，笔者对目前流行的几种网络渗透技术进行了介绍，分析了缓冲区溢出的基本原理，研究了在Windows环境中基于缓冲区溢出的网络渗透的具体实现，提出了针对缓冲区溢出攻击的网络安全防治策略.