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Orientation angle rotatability of planar serial n-link manipulators

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Science China(Technological Sciences) 2010年第6期53卷 1620-1637页

作者： LI RuiQin1,XIAO DengHong1 & DAI Jian S2 1 College of Mechanical Engineering and Automation,North University of China,Taiyuan 030051,China 2 Department of Mechanical Engineering,King’s College London,University of London,London wc2R 2LS,UK College of Mechanical Engineering and Automation North University of China Taiyuan China Department of Mechanical Engineering King’s College London University of London London UK

This paper presents a new method of analyzing the orientation angle rotatability of a planar serial n-link manipulator by examining the rotatability of its virtual equivalent *** orientation boundary region decomposition is proposed based on the polynomial discriminant derived from a serial three-link *** angle workspace indicates a set of angle ranges by which the end-effector can reach with certain orientation for every point in the reachable position *** introducing a virtual equivalent mechanism,the open-chain kinematic problem is converted into a close-chain mechanism,and the Grashof-type condition is used to examine the rotatability of the end-effector *** reachable position workspace can be divided into several Grashof intervals and non-Grashof intervals based on the extreme positions and singular configurations of a *** derived equations in this paper can be used to calculate the variation rule of the orientation angle workspace of any given planar serial n-link manipulator on the basis of its link *** orientation angle rotatability of a seven-link serial manipulator is solved by the proposed method and graphical representations of the orientation angle workspaces are mapped onto a three-dimensional coordinate *** theoretical approach has practical significance for the design of a highly dexterous serial n-link manipulator with proposed link relations.

关键词： Grashof criterion planar serial manipulator orientation angle workspace virtual equivalent mechanism

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Valuing water quality in China:purpose,approach and policy

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Journal of Environmental Sciences 1999年第3期11卷 309-315页

作者： Timothy Swanson,Brett Day,Susana Mourato Centre for Social and Economic Research on the Global Environment, Department of Economics, and School of Public Policy, University College London, Gower Street, London wc1E 6BT, United Kingdom University College London 英国

The economic valuation of water quality in a rapidly developing country such as China should be undertaken to determine when the benefits from rapid growth begin to exceed the costs from the same. The best approach is to ascertain the total economic valuation of the environmental resource. This includes all of the various uses of the resource, and even those values that are unconnected to individual use (e.g. natural and aesthetic values). A method known as contingent valuation (CV) is used to ascertain these forms of value. This approach is demonstrated here in an application to river water quality in the Beijing area. A CV study is reported in which Beijing area citizens reported an average willingness to pay about 1.3% of annual income in order to prevent further deterioration of river water quality. Aggregation over the representative population indicates that the perceived cost of further river quality deterioration is in the neighbourhood of USD 60 million. Such a measure provides some indication of the socially desired “stopping point”—— in the pursuit of economic growth at the expense of environmental quality.

关键词： water management policy environmental valuation environment development.

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Numeration and type synthesis of 3-DOF orthogonal translational parallel manipulators

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Progress in Natural Science:Materials International 2008年第5期18卷 563-574页

作者： Jingjun Yua, Jian S. Dai b, Shusheng Bi a, Guanghua Zong a a Robotics Institute, Beihang University, Beijing 100083, China b Department of Mechanical Engineering, School of Physical Science and Engineering, King’s College, University of London, The Strand, London wc2R 2LS, UK Robotics Institute Beihang University Beijing 100083 China Department of Mechanical Engineering School of Physical Science and Engineering King’s College University of London The Strand London WC2R 2LS UK

Low-degree-of-freedom (Low-DOF) parallel manipulators (PMs) have drawn extensive interests, particularly in type synthesis in which two main formal approaches were established by using the reciprocal screw system theory and Lie group theory. This paper aims at numeration and type synthesis of orthogonal translational parallel manipulators (OTPMs) by resorting to an integration of the group- based method and graphical representation of the topology. For this purpose, the concept of Cartesian DOF-characteristic matrix, orig- inated from displacement subgroup and displacement submanifold, is proposed. A new approach based on the combination of the atlas of Cartesian DOF-characteristic matrix and the displacement group-theoretic method is addressed for both exhaustive classi cation and type synthesis of OTPMs. The proposed approach is prone to construct an orthogonal structure and is easy to realize the complete clas- si cation and exhaustive enumeration of this class of low-DOF PMs.

关键词： Type synthesis Displacement group Orthogonal translational parallel manipulator

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全数字频谱兼容高清晰度电视系统

国际广播电视技术 1992年第2期6卷 26-33页

作者： Lupl.,wc 李幼林

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艾滋病与免疫系统

科学（中文版） 1994年第1期 50-58页

作者： Gree.,wc 郭凯声

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佩戴式心电图监护器的心律失常检测程序

国外医学.生物医学工程分册 1981年第1期 58-59页

作者： Muller wc 彭立言

引言用以分析心律失常的这一程序在RCA COSMAC微型计算机存贮器中占4K字节,其中2K字节为程序本身,2K字节用以存贮心电图数据和数值表。程序包括5个部分:预置、心律失常检测、报警、传输和手动超控。此程序按中断方式运行,其组织方式使... 详细信息

引言用以分析心律失常的这一程序在RCA COSMAC微型计算机存贮器中占4K字节,其中2K字节为程序本身,2K字节用以存贮心电图数据和数值表。程序包括5个部分:预置、心律失常检测、报警、传输和手动超控。此程序按中断方式运行,其组织方式使其得以最好地利用两次中断之间的指令。中断是由于调定每5毫秒转换一次模数转换器而造成的。计算机执行一条指令平均需时8微秒,因此在每次模数转换时此程序仅能处理625条指令。

关键词：心律失常程序 QRS 常检心电图电诊断图压缩算法缓冲器波群

The sloshing of stratified liquid in a two-dimensional rectangular tank

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Science China(Physics,Mechanics & Astronomy) 2011年第1期54卷 2-9页

作者： WU GuoXiong1,2 1 State Key Laboratory of Ocean Engineering,College of Naval Architecture,Ocean and Civil Engineering,Shanghai Jiao Tong University,Shanghai 200240,China 2 Department of Mechanical Engineering,University College London,Torrington Place,London wc1E 7JE,UK State Key Laboratory of Ocean Engineering College of Naval Architecture Ocean and Civil Engineering Shanghai Jiao Tong University Shanghai China Department of Mechanical Engineering University College Londo London UK

The sloshing of inviscid liquid of stratified density in a rectangular tank is *** the flow is no longer irrotional,the governing equation is found to be quite different from the Laplace equation used for the liquid of constant *** particular it contains terms of mixed temporal and spatial *** problem is solved based on the variable separation method and Laplace transform for the constant Vaisala-Brunt *** is found that the stratification of density may have small effects on those natural frequencies associated with the constant density,but many new natural frequencies have appeared as a result of its effect.

关键词： sloshing density stratification resonance rectangular tank

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老年心脏钙化综合征

国外医学(老年医学分册) 1988年第3期 111-112页

作者： Robert wc 马毅志

动脉粥样硬化高发区的老年人心脏常有钙化沉积物,最常见的沉积部位为心外膜冠状动脉、二尖瓣瓣环区域、主动脉瓣瓣叶和左室乳头肌。上述部位钙化可加重冠状动脉狭窄和导致二尖瓣返流和/或二尖瓣狭窄、主动脉瓣狭窄和/或返流及乳头肌功... 详细信息

动脉粥样硬化高发区的老年人心脏常有钙化沉积物,最常见的沉积部位为心外膜冠状动脉、二尖瓣瓣环区域、主动脉瓣瓣叶和左室乳头肌。上述部位钙化可加重冠状动脉狭窄和导致二尖瓣返流和/或二尖瓣狭窄、主动脉瓣狭窄和/或返流及乳头肌功能障碍,从而出现相应的临床表现,由于老年人心脏钙化与冠状动脉粥样硬化常常存在于同一心脏而且心脏钙化综合征的易患因素与冠状动脉粥样硬化的易患因素相同,故有理由认为二者的病因相同。

关键词：主动脉瓣狭窄冠状动脉粥样硬化瓣环瓣叶老年人二尖瓣狭窄心脏综合征综合病症

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应用分形和多重分形几何学模拟地震小断层

世界石油科学 1995年第1期 26-30,102页

作者：乐有喜 Belf.,wc

油藏描述中的一个重要问题是对未被地震技术确定出来的断层进行预测。这些断层能够破坏流动单元的连续性，也可能是水平钻井的潜在目的层，描述这些断层分布的方法之一是随机模拟。本文介绍了一种用分形和多重分形概念来模拟地下小断层... 详细信息

油藏描述中的一个重要问题是对未被地震技术确定出来的断层进行预测。这些断层能够破坏流动单元的连续性，也可能是水平钻井的潜在目的层，描述这些断层分布的方法之一是随机模拟。本文介绍了一种用分形和多重分形概念来模拟地下小断层的数量，长度，排列方向和空间分布的技术。这种方法是利用断层的分形性质来确定它们真实的长度分布，断层是以多重分形谱表征的，而不只是以单一的分数维来表征。

关键词：分形几何模拟断层油气勘探