龙滩工程按正常蓄水位400m方案一次建成效益巨大

2003年11月龙滩工程将实现大江截流，随着工程建设的全面推进，越发显出实施龙滩水电站正常蓄水位400m一次建成方案的重要性和紧迫性。相对分期建设而言，400m水位一次建成，工程效益大、增加投资少、无后期加高过程中的各种技术难题，基本不影响电站的初期发电效益，水轮机设计与运行问题少、机组运行条件好，电站规模效益与社会综合效益巨大，有利于移民安置和库区经济的发展，对国家、地方、企业均十分有利，因此应尽快决策实施400m一次建成方案。     

The principle and fundamental characteristics of brushless three-phase synchronous induction motor with two stators

Brushless three-phase synchronous motor involving a rotating ac exciter on the same shaft as the motor and with the windings linked through a shaft-mounted rectifier is widely used as medium and large capacity machines. However, the motor needs to fit with damping windings for self-starting outside of the field winding in the rotor and needs to equip discharge resistance with complex electronic device to dispose of electromagnetic force induced in the field winding at starting. Therefore, the rotor structure is very complex, and there are disadvantages, especially for the robust and highly reliable motor that is desired. To solve the problem found in traditional motors, the authors proposed a brushless three-phase synchronous induction motor with two stators and one wound rotor. This problem is solved because the proposed motor is of two-stators structure: the rotor winding operates as a secondary winding of induction motor at starting and as the field winding at synchronous operation. The motor can self-start as a wound-rotor induction motor without external secondary resistance. Therefore, discharge resistance is not necessary; the starting equipment is very simple and the rotor structure is robust. It is possible to start with high torque. In this paper, the basic constitution of the proposed motor and the principles of operation are described in detail. The experimental results at starting and pulling into synchronism are shown for confirming the principles of operation and the experimental and numerical results of the starting characteristics. The load ones and the generating ones are shown and then the practical use of the proposed motor is confirmed.     

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。     

Analysis and design of Hermite subdivision schemes

Published online: 14 May 2002     

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     

大同煤矿集团公司供水处局域网的开发和应用

介绍了大同煤矿集团公司供水处处级局域网的设计原则及开发过程，对外级局域网1年来取得的管理效果、经济效益、社会效益进行了简明的阐述。     

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