Eight-node conforming straight-side quadrilateral element with high-order completeness (QH8-C1)

A new eight-node conforming quadrilateral element with high-order completeness, denoted as QH8-C1, is proposed in this article. First, expressions for the interpolation displacement function satisfying the requirements for high-order completeness in the global coordinate system are constructed. Second, the displacement function expression in global coordinates is transformed into isoparametric coordinates, and the relationships between the two series of coefficients for the two kinds of displacement function expressions are found. Third, the displacement function expression is modified to satisfy the requirements of nodal freedom and interelement boundary continuity. The key to the new element construction is the derivation of the linear relationship expressions among 12 coefficients of element displacement interpolation polynomials in the global and isoparametric coordinate systems. As a result, the relationship between quadratic completeness and interelement continuity is explicitly given, and a proof of the completeness and the continuity was conducted to theoretically guarantee the validity of the derivation results. Furthermore, in order to verify the correctness of the theoretical work, nine numerical examples were performed. The computation results from these examples demonstrate that QH8-C1 exhibited excellent performance, including high simulation accuracy, fast convergence, insensitivity to mesh distortion, and monotonic convergence.     

浅析建设工程施工合同中几个条款

对比FID IC施工合同条件,指出了我国建设工程施工合同示范文本中几个条款中的不足,并提出了改进的相应建议。改进后的合同更加完备,将有利于减少合同履行中纠纷的出现。     

瑞雷波检测在水泥土搅拌桩中的应用

本文详细介绍了瑞雷波检测水泥土搅拌桩的方法和步骤,对该方法加以详细设计,并结合自己做过的工程实例具体分析、总结。通过与其他常规方法的对比、分析总结出该方法的优点并对桩基无损检测给与了建议。     

On the degree of completeness of cryptographic functions

This paper discusses the degree of completeness of cryptographic functions, which is one of the cryptographic criteria should be considered in the design of stream ciphers. We establish the re- lationships between the degree of completeness and other cryptographic criteria. For resilient Boolean functions, a method to enhance the degree of completeness is proposed, while the nonlinearity and the algebraic degree do not decrease. Moreover, two constructions of resilient functions are provided, which have optimal degree of completeness, high nonlinearity, and high algebraic degree.     

梯形模糊数上的完备度量及其在多属性决策中的应用

为充分利用梯形模糊数的信息,本文定义了梯形模糊数上一种新的距离,证明了该距离具有完备性。利用这种距离,针对梯形模糊数上的多属性决策问题,给出了一种基于理想点的决策方法。对属性权重的"归一化"处理使得这种方法具有简单易行的优点,最后以实例说明了该方法的有效性。     

张家口地区电子文献传递系统(EDDS)的开发研究

随着人们对信息资源的需求及文献传递工作的重视,文献传递的服务模式及发展趋势逐渐成为社会所关注的问题.本课题通过分布式文献传递的服务模式,利用完备的网络搜索系统模型,构建张家口地区高校图书馆之间的电子文献传递桥梁.     

分布式失效检测算法的研究与分析

在受限异步假设的前提下,本文提出了基于“存活授权／自杀失效”方法的分布式失效检测算法,并从用户进程角度给出了完整性和精确性的定义。     

全自主移动机器人在未知环境中的运动规划

针对机器人在未知环境中的运动规划,本文给出了一种基于激光传感器的完备路径规划算法,使机器人可以有效地扫描整个未知环境。使得机器人扫描整个未知环境的行走路径较短,所需的时间也较短。计算机仿真验证了算法的可行性,同时体现了算法的优越性。     

卷烟阴燃完全性对常规烟气指标的影响

采用自制设备测定中国50种不同牌号卷烟实际可燃率、自由燃烧速度,并结合气相色谱分析常规烟气成分。结果表明:①实际可燃率与自由燃烧速度呈极显著负相关,即卷烟阴燃越完全,自由燃烧速度越慢。②实际可燃率与常规烟气中的总粒相物(total particulate matter,TPM)、烟碱、焦油、抽吸口数指标均呈极显著正相关,其中与TPM相关性最强;自由燃烧速度与TPM、烟碱、焦油、抽吸口数指标均呈极显著负相关,其中与TPM、焦油相关性较强。综合分析卷烟阴燃越完全,自由燃烧速度越慢,则抽吸口数越多,焦油含量越高。