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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 2.02.0,China 2.department of mechanical engineering,University college london,torrington place,london wc1e 7je,uk 1. State Key Laboratory of Ocean engineering College of Naval Architecture Ocean and Civil Engineering Shanghai Jiao Tong University Shanghai 20024 China2. Department of Mechanical Engineering University College Londo Torrington Place London WC1E 7JE 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

The Design of Lens Imaging System byMeans of Fractional Fourier Transform

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Chinese Journal of Lasers 2002年第2期11卷 27-32页

作者： CHeN Jiannong XU Qiang (department of Physics, Yantai Teachers’ University, Yantai 2.402., China)D.R.Selviah(department of electronic and electrical {2., University college london, torrington place, london wc1e 7je, uk) department of Physics Yantai Teachers' University Yantai 264025 department of electronic and electrical engineering University College London Torrington Place 英国 London WC1E 7JE

The relation between the 2.d fractional Fourier transform and the imaging process of an optical system is discussed. By changing the coordinate scales of the input plane in respect to the magnification of the optical imaging system, the fractional Fourier transform can be a powerful tool in designing specific imaging system. The Gaussian imaging formula of single lens is obtained by using the tool. Finally the procedures are generalized for designing a double-lens imaging system through an example.

关键词： lens imaging system fractional Fourier transform Gaussian imaging formula

RADIATION AND DIFFRACTION OF WATeR WAVeS BY A SUBMeRGeD CIRCULAR CYLINDeR AT FORWARD SPeeD

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Journal of Hydrodynamics 1993年第4期5卷 85-96页

作者： G.X.Wu department of mechanical {2.,University college london,torrington place,london wc1e,7je,U.K.

The wave radiation and diffraction by a submerged circular cylinder in deep water is analysed by the multipole expansion *** theory is based on the inviscid and linearized potential flow.

关键词： flow water wave circular cylinder

Crank conditions and rotatability of 3-RRR planar parallel mechanisms

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Science China(Technological Sciences) 2009年第12期52卷 3601-3612页

作者： LI RuiQin 1 &DAI Jian S 2.1 college of mechanical {2. and Automation,North University of China,Taiyuan 030051,China 2.department of mechanical engineering,King’s college london,University of london,wc2. 2.S,uk college of mechanical {2. and Automation North University of China Taiyuan 030051 China department of mechanical {2. King’s College London University of London WC2R 2LS London UK

This paper investigates the rotatability of planar parallel mechanisms by revealing the crank conditions that relate to link *** paper extends the theorem of assemblability and the rotatability criterion and applies these criteria to parallel mechanisms in investigating the crank conditions of a parallel mechanism,leading to classification of three types of crank existing conditions including three-crank’s,six-crank’s and nine-crank’s of 3-RRR planar parallel *** results are summarized as constraint conditions in relation with link parameters with a concluding table and case studies.

关键词： crank rotatability planar parallel mechanism

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 {2. and Automation,North University of China,Taiyuan 030051,China 2.department of mechanical engineering,King’s college london,University of london,london wc2. 2.S,uk 1. college of mechanical {2. and Automation North University of China Taiyuan 030051 China2. Department of Mechanical Engineering King’s College London University of London London WC2R 2LS 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

SeCOND ORDeR TRANSIeNT WAVeS AROUND A VeRTICAL CYLINDeR IN A TANK

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Journal of Hydrodynamics 1995年第4期7卷 72-81页

作者： Q. W. Ma, G. X. Wu(department of mechanical {2. University college london torrington place london wcIe 7je )

The free surface problem bound by two cylinders is analysed based on the velocity potential theory. An analytical solution in the take domain is obtained up to the second order in the perturbation expansion. The results are compared with those obtainal from the fully nonlinear theory based on a finite element *** is found that the second order solutiongives a fsr better agreement with the fully nonlinear solution.

关键词： velocity potential analytical solution time domain fully nonlinear theory,transient waves vertical cylinder

Particle monitoring techniques for water treatment applications

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Journal of environmental Sciences 1999年第3期11卷 328-333页

作者： John Gregory department of Civil and environmental engineering, University {2. london, Gower St, london wc1e 6BT, uk University college london 英国

A simple optical technique based on fluctuations in light transmitted through flowing suspensions has proved useful in two distinct water treatment applications. The first of these is the monitoring and control of coagulation/flocculation processes, where information on optimum coagulant dosages as well as on the dynamics of floc formation can be derived. The method is suitable for a very wide range of particle concentrations, up to levels found in highly turbid river waters. The second application is as a very sensitive monitor of particles in filtered water. Such monitoring can help to ensure the effective removal of pathogens such as Cryptosporidium from drinking water. Brief accounts of these techniques are given, together with some examples of their use.

关键词： Cryptosporidium coagulation flocculation fluctuations monitoring particles water treatment.

Dual-turbo receiver architecture for turbo coded MIMO-OFDM systems

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Science China(Information Sciences) 2012年第2期55卷 384-395页

作者： WANG WenJin1,GAO XiQi1,WU XiaoFu2.YOU XiaoHu1,ZHAO ChunMing1 & WONG Kai-Kit3 1National Communication Research Laboratory,Southeast University,Nanjing 2.0096,China 2.anjing Institute of Communications engineering,Nanjing 2.0007,China 3department of electrical and electronic engineering,University college london london wc1e 7je,uk 1. National Communication Research Laboratory Southeast University Nanjing 210096 China2. Nanjing Institute of Communications Engineering Nanjing 210007 China3. Department of Electrical and Electronic Engineering University College London London WC1E 7JE UK

This paper presents a novel architecture of iterative receivers with two layers of iterations for turbo coded multiple-input and multiple-output orthogonal frequency-division multiplexing(MIMO-OFDM)systems,where soft messages are passed not only between the MIMO detector and the turbo decoder,but also between the two component decoders within the turbo *** first derive the factor graph representation of a turbo coded system as a basic building block for developing the iterative ***,a new soft message passing schedule over the factor graph is proposed,resulting in the proposed dual-turbo receiver architecture(DTRA).In DTRA,the MIMO detector and the turbo decoder work concurrently,and the soft messages for both layers of iterations are updated instantaneously,instead of the block-based exchange of soft messages in the conventional iterative *** so doing,the processing latency can be greatly reduced while low computational complexity can be achieved.

关键词： MIMO-OFDM iterative detection and decoding turbo codes

Advances in numerical methods for the solution of population balance equations for disperse phase systems

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Science China Chemistry 2009年第8期52卷 1063-1079页

作者： SU JunWei1,GU ZhaoLin2.3 & XU X.Yun41 department of mechanical {2. and Automation,School of mechanical {2.,Xi’an Jiaotong University,Xi’an 710049,China 2.Key Laboratory of Mechanics on Disaster and environment in Western China,Ministry of education,Lanzhou 730000,China 3 department of environmental Science and Technology,School of Human Settlements and Civil {2.,Xi’an Jiaotong University,Xi’an 710049,China 4 department of Chemical {2.,Imperial college london,london SW7 2.Z,{12. 1. department of mechanical {2. and Automation School of Mechanical Engineering Xi’an Jiaotong University Xi’an 710049 China 2. Key Laboratory of Mechanics on Disaster and environment in Western China Ministry of Education Lanzhou 730000 China 3. department of environmental Science and Technology School of Human Settlements and Civil Engineering Xi’an Jiaotong University Xi’an 710049 China 4. department of Chemical engineering Imperial College London London SW7 2AZ UK

Accurate prediction of the evolution of particle size distribution is critical to determining the dynamic flow structure of a disperse phase system.A population balance equation(PBe),a non-linear hyperbolic equation of the number density function,is usually employed to describe the micro-behavior(aggregation,breakage,growth,etc.) of a disperse phase and its effect on particle size *** solution is the only choice in most *** this paper,three different numerical methods(direct discretization methods,Monte Carlo methods,and moment methods) for the solution of a PBe are evaluated with regard to their ease of implementation,computational load and numerical *** attention is paid to the relatively new and superior moment methods including quadrature method of moments(QMOM),direct quadrature method of moments(DQMOM),modified quadrature method of moments(M-QMOM),adaptive direct quadrature method of moments(ADQMOM),fixed pivot quadrature method of moments(FPQMOM),moving particle ensemble method(MPeM) and local fixed pivot quadrature method of moments(LFPQMOM).The prospects of these methods are discussed in the final section,based on their individual merits and current state of development of the field.

关键词： population balance equation direct discretization method Monte Carlo method moment methods disperse phase system