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Rare Metals 2008年第3期27卷 266-272页

作者： ZHANG Yao~(a,b) CHUNG Chiyuen~b ZHU Min~a ~a School of mechanical Engineering,South china University of Technology,Guangzhou 510640,china ~b department of Physics and Materials Science,City University of Hong Kong,Hong Kong,china [a]School of mechanical Engineering South China University of Technology Guangzhou 510640 China [b]Department of Physics Materials Science City University of Hong Kong Hong Kong China

Layered LiCoO2（HT-LiCoO2）films were grown on Pt-metalized silicon（PMS）substrates and polished bulk nickel（PbN）substrates by pulsed laser *** effects of substrate temperature,oxygen pressure,and substrate surface roughness on the microstructure of LiCoO2 films were *** has been found that a higher substrate temperature and a higher oxygen pressure favor the formation of better crystallized and less lithium-deficient HT-LiCoO2 *** HT-LiCoO2 film deposited on PbN substrates consists of large randomly orientated equiaxial grains,whereas on PMS substrate,it is made up of loosely packed highly[001]preferential orientated triangular shaped grains with the average grain size less than 100 *** measurements show that the highly[001]preferentially orientated nanostructured HT-LiCoO2 thin film grown on PMS substrate has good structural stability upon lithium insertion/extraction and can deliver an initial discharge capacity of approximately 45μA·h·cm-2·μm-1with a cycling efficiency of above 99% at the charge/discharge rate of 0.5 C.

关键词： thin film LiCoO2 pulsed laser deposition electrochemical properties thin film growth

PROPULSIVE PERFORMANCE AND VORTEX SHEDDING OF A FOIL IN FLAPPING MOTION

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Journal of Hydrodynamics 2003年第5期15卷 7-12页

作者： Yang Yan, Lu Xi yun, Yin Xie zhen department of Mechanics and mechanical Engineering, University of Science and Technology of china, Hefei 230026, china, department of Mechanics and mechanical Engineering University of Science and Technology of China Hefei 230026 China

The propulsive performance and vortex shedding of oscillating foil, whichmimics biological locomotion, were numerically investigated. The objectives of this study were todeal with unsteady force, in particular thrust force, exerted on the foil in pitching and plungingmotions, and to explore the relation of the propulsive performance with vortex structures near thefoil and vortex shedding in the near wake. The two-dimensional incompressible Navier-Stokesequations in the vorticity and stream-function formulation were solved by fourth-order essentiallycompact finite difference schemes for the space derivatives and a fourth-order Runge-Kutta schemefor the time advancement. To reveal the mechanism of the propulsive performance, the unsteady forceand the shedding of the trailing- and leading-edge vortices of the foil were analyzed. The effectsof some typical factors, such as the frequency and amplitude of the oscillation, the phasedifference between the pitching and plunging motions, and the thickness ratio of the foil, on thevortex shedding and unsteady force were discussed.

关键词： vortex dynamics vortex shedding thrust force unsteady flow flappingmotion

Selections of data preprocessing methods and similarity metrics for gene cluster analysis

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Progress in Natural Science:Materials International 2006年第6期16卷 607-613页

作者： YANG Chunmei, WAN baikun and GAO Xiaofeng (department of biomedical Engineering and Scientific Instrumentations, Tianjin University, Tianjin 300072, china Motorola (china) electronics Ltd., Tianjin 300457, china) [a]department of biomedical Engineering and Scientific Instrumentations Tianjin University Tianjin China [b]Motorola (china) electronics Ltd. Tianjin China

Clustering is one of the major exploratory techniques for gene expression data analysis. Only with suitable similarity metrics and when datasets are properly preprocessed, can results of high quality be obtained in cluster analysis. In this study, gene expression datasets with external evaluation criteria were preprocessed as normalization by line, normalization by column or logarithm transformation by base-2, and were subsequently clustered by hierarchical clustering, k-means clustering and self-organizing maps (SOMs) with Pearson correlation coefficient or Euclidean distance as similarity metric. Finally, the quality of clusters was evaluated by adjusted Rand index. The results illustrate that k -means clustering and SOMs have distinct advantages over hierarchical clustering in gene clustering, and SOMs are a bit better than k-means when randomly initialized. It also shows that hierarchical clustering prefers Pearson correlation coefficient as similarity metric and dataset normalized by line. Meanwhile, k -means clustering and SOMs can produce better clusters with Euclidean distance and logarithm transformed datasets. These results will afford valuable reference to the implementation of gene expression cluster analysis.

关键词： gene expression cluster analysis data preprocessing similarity metrics Rand index.

SH-guided waves in layered piezoelectric/piezomagnetic plates

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Progress in Natural Science:Materials International 2009年第7期19卷 811-816页

作者： Guoquan Nie a,b, Zijun An a, Jinxi Liu b a College of mechanical Engineering, Yanshan University, Qinhuangdao 066004, china b department of Engineering Mechanics, Shijiazhuang Railway Institute, Shijiazhuang 050043, china [a]College of mechanical Engineering Yanshan University Qinhuangdao 066004 China [b]Department of Engineering Mechanics Shijiazhuang Railway Institute Shijiazhuang 050043 China

The propagation of shear horizontal (SH) guided waves in a coupled plate consisting of a piezoelectric layer and a piezomagnetic layer is studied. both the layers are transversely isotropic and perfectly bonded along the interface. The upper and the lower surfaces of the plate are assumed to be mechanically free, electrically open and magnetically closed. Two different cases are considered. One is that the bulk shear wave velocity of piezoelectric material is larger than that of piezomagnetic material. The other is that the bulk shear wave velocity of piezomagnetic material is larger than that of piezoelectric material. The dispersion relation is obtained while the phase velocity is among the bulk shear wave velocity of two different layers. The numerical results show that the phase velocity approaches the smaller bulk shear wave velocity of the material in the system with the increase in the wave number for different modes. The thickness ratio and the properties of the piezoelectric material have great effect on the dispersion behaviors. The results of this paper can offer some fundamental theory to the application of piezoelectric/piezomagnetic composites or structures.

关键词： Piezoelectric material Piezomagnetic material SH-guided wave Dispersion relation

bREAKING WAVE FORCES ON VERTICAL CYLINDERS

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Journal of Hydrodynamics 2002年第4期14卷 110-112页

作者： Ma Ru-jian, Li Gui-xi department of mechanical and Electronic Engineering, Jinan University, Jinan 250022, china department of mechanical and Electronic Engineering Jinan University Jinan 250022 China

The breaking wave forces on vertical cylinders in shallow waters were studied by means of experimental methods. The results indicate that the breaking wave pressure is distributed exponentially with respect to water depth. An experimental formula was given using the test data. Compared with test data, the calculated breaking wave forces are in good agreement with the test data.

关键词： breaking wave forces pressure distribution of breaking waves experimental study

Constraints on the late Mesozoic regional angular unconformity in West Liaoning-North Hebei by LA-ICP-MS dating

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Progress in Natural Science:Materials International 2008年第11期18卷 1395-1402页

作者： Hong Zhang~(a,b,*) Wenmin Guo~a Xiaoming Liu~b a College of mechanical and Energy Engineering,Jiangsu Polytechnic University,Changzhou 213016,china b Key Laboratory of Continental Dynamics,department of Geology,Northwest University,Xi’an 710069,china College of mechanical and Energy Engineering Jiangsu Polytechnic University Changzhou 213016 China Key Laboratory of Continental Dynamics Department of Geology Northwest University Xi’an 710069 China

The angular unconformity between the Tuchengzi Formation and the Zhangjiakou Formation in the Chengde area is commonly regarded as the direct evidence of boundary between Jurassic and Cretaceous systems,and as the evidence of tectonic transformation interfaces in Mesozoic Era in the West Liaoning-North ***,the lower boundary age of the Zhangjiakou Formation in the Chengde was to be thought about 135 Myr in the *** on the detailed study and systematic sampling in Yixian-beipiao,Lingy- uan,Chengde and Luanping areas in the field,the authors obtained the following isotopic ages by means of LA-ICP-MS dating:In the Lingyuan area,the Zhangjiakou Formation and the Yixian Formation are in angular unconformable contact;the age range of the Zhangjiakou Formation volcanic rock is from 133 to 130 Myr(seven samples),and that of the Yixian Formation volcanic rock is from 126 to 121 Myr(eleven samples).In the Luotuoshan of Chengde,the Tuchengzi Formation and the Zhangjiakou Formation are in angu- lar unconformable contact;the age at the lower Zhangjiakou Formation is about 124 Myr(one sample),which reflects that the age range of the lower Zhangjiakou Formation is from 129 to 124 Myr combined with the previous *** the Luanping basin,there is the larg- est sediment gap in upper Mesozoic,whose lower boundary age is confined in 131 to 130 *** the Yixian-beipiao area,the second Member of the Yixian Formation,making up more than 3/4 thickness of the Yixian Formation,was formed in 126 to 119 Myr,and the age of the Yixian Formation at the bottom is about 132 ***,the upper boundary age of the Tuchengzi Formation is about 136 Myr in the West Liaoning-North Hebei *** on the above isotopic data combined with the geological characteristics in the field in the West Liaoning-North Hebei region,it reflects that there was a widespread tectonic event in the period of 136 to 126 Myr (mainly in 130-126 Myr)in the West Liaoning-North Hebei,and it formed the

关键词： Dating LA-ICP-MS Angular unconformity Interface of tectonic transformation West Liaoning-North Hebei

AN INVESTIGATION OF TURbULENT HEAT TRANSFER IN CHANNEL FLOWS bY LARGE EDDY SIMULATION

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Journal of Hydrodynamics 2002年第2期14卷 29-35页

作者： Dong Yu-hong, Zhong Feng-quan, Lu Xi-yun, Zhuang Li-xian department of Mechanics and mechanical Engineering, University of Science and Technology of china, Hefei 230026, china department of Mechanics and mechanical Engineering University of Science and Technology of China Hefei 230026 China

Large Eddy Simulation (LES) of fully developed turbulent channel flow with heat transfer was performed to investigate the effects of the Reynolds number on the turbulence behavior. In the present study, the bottom wall of the channel was cooled and the top wall was heated. The Reynolds numbers, based on the central mean-velocity and the half-width of the channel, were chosen as 4000, 6000, 10 4 and 2×10 4, and the Prandtl number as 1.0. To validate our calculations, the present results were compared with available data obtained by Direct Numerical Simulation (DNS), which proves to be in good agreement with each other. To reveal the effects of the Reynolds number, some typical quantities, including the velocity fluctuations, temperature fluctuation, heat fluxes and turbulent Prandtl number, were studied.

关键词： Large Eddy Simulation (LES) turbulent channel flow Subgrid Scale (SGS) model heat transfer stratified turbulence

FREE-SURFACE WAVES AND FAR WAKES GENERATED bY A FLOATING bODY IN A VISCOUS FLUID

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Journal of Hydrodynamics 2003年第4期15卷 10-16页

作者： Lu Dong-qiang department of mechanical Engineering, The University of Hong Kong, Hong Kong, china Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, Shanghai 200072, china department of mechanical Engineering The University of Hong Kong Hong Kong China Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai 200072 China

The free-surface waves and the flow field due to a body moving on the surfaceof an incompressible viscous fluid of infinite depth were studied analytically. The floating bodywas modeled as a normal point pressure on the free surface. based on the Oseen approximation forgoverning equations and the linearity assumption for boundary conditions, the exact solutions inintegral form for the free-surface elevation, the velocities and the pressure were given. byemploying Lighthill's two-stage scheme, the asymptotic representations in far field for largeReynolds numbers were derived explicitly. The effect of viscosity on the wave profiles was expressedby an exponential decay factor, which removes the singular behavior predicted by the potentialtheory.

关键词： free-surface waves velocity distribution floating body viscosity asymptotic representation light-hill's two-stage scheme

A COMPUTATIONAL STUDY ON bACKWARDS WI MMING HYDRODYNAMICS IN THE EELANGUILLA ANGUILLA

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Journal of Hydrodynamics 2005年第4期17卷 438-447页

作者： HU Wen-rong TONG bin-gang MA Hui-yang LIU Hao department of Physics Graduate School of the Chinese Academy of Sciences Beijing 100039 China department of Engineering Mechanics Shanghai Jiaotong University Shanghai 200240 China department of electronics and mechanical Engineering Chiba University Japan

Eels can perform both forward and backward undulatory swimming but few studies are seen on how eels propel themselves backward. A computational study on the unsteady hydrodynamicsoof the backward swimming in the eel anguilla anguilla is carried out and presented. A two-dimensional geometric model of the European eel body in its middle horizontal section is appropriately approximated by a NACA0005 airfoil. Kinematic data of the backward and forward swimming eel used in the computational modeling are based on the experimental results of the European eel. Present study provided the different flow field characteristics of three typical cases in the backward swimming, and confirmed the guess of Wu： When the eel swims steadily, the vortex centers of the reversed von Kármán vortex street are aligned approximately. An extensive comparison between the backward and forward swimming further reveals that the controllable parameters, such as frequency, amplitude and wavelength of the traveling wave, have a similar influence on the propulsion performance as in forward swimming. but it is shown that the backward swimming does not be a ＂reversed＂ forward swimming one. The backward swimming does show significant discrepancy in the propulsion performance： utilization of a constant-amplitude wave profile enables larger force generation for maneuverability but with much lower propulsive efficiency instead of the linear-increasing amplitude wave profile in the forward swimming. The actual swimming modes eels choose is the best choice associated with their propulsive requirement, as well as their physiological and ecological adaptation.

关键词： anguilla anguilla backward swimming hydrodynamics 2-D N-S equation solution