修井机多桥间转向传动机构的设计

对于大型修井机采用的重型底盘,多桥转向系统是底盘开发中的关键技术之一。在分析目前修井机采用的转向传动结构(方案1)存在问题的基础上,参照军用车底盘的应用案例又提出了2种方案,经对比分析,确定了最佳的传动机构新方案,并根据多桥转向理论和四连杆机构的几何关系对该机构进行了参数确定。通过实际应用,证明该转向传动布置方案具有传动误差小、不产生附加转向、现场调节安装方便、易于组织生产等特点。     

井下减速器传动方案分析

结合井下减速器的结构特点，分析了定轴轮系传动、2K-H型行星轮系传动、3K行星轮系传动、少齿差行星轮系传动4种传动方案，选择内齿作为输出轴的少齿差行星轮系传动方案更符合涡轮钻具的传动要求和井下工具结构特点。少齿差行星轮系的研制、开发、应用可降低涡轮钻具转速，提高扭矩，提高深井钻速。     

西安地铁区间隧道通过地裂缝带的施工方案

通过对西安地铁区间隧道通过地裂缝的特点分析,提出了几种地铁区间隧道通过地裂缝的方法,指出地铁结构采用这些方法能够适应地裂缝的变形发展,并在地裂缝活动的情况下维持地面交通和地铁的正常运营。     

3G中的QoS结构及无线资源分配策略

在3G（第3代移动通信系统）中，为了给不同类型的业务提供不同级别的端到端QoS，网络资源必须进行合理分配。QoS和资源分配是密不可分的，而无线资源分配显得尤为重要。文中提出了UMTS的QoS结构，分3部分对空中接口部分的QoS（即无线资源分配策略问题）进行了讨论：首先提出了一种RRA算法，接着讨论了W－CDMA和TD－CDMA系统的无线资源分配问题，最后讨论了下行链路及上行链路的呼叫允许控制（CAC）。     

Analysis and design of Hermite subdivision schemes

Published online: 14 May 2002     

Model checker aided design of a controller for a wafer scanner

For a case-study of a wafer scanner from the semiconductor industry it is shown how model checking techniques can be used to compute (1) a simple yet optimal deadlock avoidance policy, and (2) an infinite schedule that optimizes throughput. in the absence of errors. Deadlock avoidance is studied based on a simple finite state model using Smv, and for throughput analysis a more detailed timed automaton model has been constructed and analyzed using the Uppaal tool. The Smv and Uppaal models are formally related through the notion of a stuttering bisimulation. The results were obtained within 2 weeks, which confirms once more that model checking techniques may help to improve the design process of realistic, industrial systems. Methodologically, the case study is interesting since two models were used to obtain results that could not have been obtained using only a single model. Supported by the European Community Project IST-2001-35304 (Ametist), http://ametist.cs.utwente.nl/.     

三峡工程明渠提前截流方案及水力学试验研究

论述了三期明渠提前截流方案的综合比较分析及截流水力学试验研究成果。认为拟定的提前截流诸方案各有利弊 ,其截流难度较初设方案显著增加。对于截流“基本方案”及“比较方案”的成功实施 ,必须辅之以一定的工程技术措施降低截流难度     

三元乙丙橡胶卷材在地下防水工程中的应用

地下防水工程既是一项系统工程，又是一项隐蔽工程，如何选择防水材料和控制工程质量显得到关重要。本文结合工程实例，介绍了三元乙丙橡胶卷材在地下防水工程中的应用，分析了三元乙丙卷材的特点，提出了地下水的技术方案，施工操作要求，质量过程控制要点和施工注意项，本文对三元乙丙卷材的工程应用具有指导和借鉴意义。     

The ponding problem on elastic membranes: an analog equation solution

 In this paper, the nonlinear response of elastic membranes with arbitrary shape under partial and full ponding loads has been analyzed. Large deflections are considered, which result from nonlinear kinematic relations. The problem is formulated in terms of the displacements components and the three coupled nonlinear governing equations are solved using the analog equation method (AEM). The membrane may be prestressed either by prescribed boundary displacements or tractions. Using the concept of the analog equation the three coupled nonlinear equations are replaced by three uncoupled Poisson's equations with fictitious sources under the same boundary conditions. Subsequently, the fictitious sources are established using a procedure based on the BEM and the displacement components as well as the stress resultants at any point of the membrane are evaluated from their integral representations. In addition to the geometrical nonlinearity, the ponding problem is itself nonlinear, because the ponding load depends on the deflection surface that it produces. Iterative schemes are developed which converge to the equilibrium state of the membrane under the ponding loads. Several membranes are analyzed which illustrate the method and demonstrate its efficiency and accuracy. The method has all the advantages of the pure BEM, since the discretization and integration is limited only to the boundary. Received 28 July 2001