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On the Viscous Flow Past A Sphere: A SimplifiedDescription

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Communications in Nonlinear science and Numerical Simulation 1999年第2期4卷 104-109页

作者： Shijun LIAO(school of Naval Architecture & Ocean engineering, shanghai jiaotong university,shanghai 200030, china)E-mail: sjliao@*** school of Naval Architecture & Ocean engineering Shanghai Jiaotong University Shanghai 200030 China

We apply a new asymptotic technique for nonlinear problems, namelythe homotopy analysis method (HAM) proposed by LIAO, to give analytic solutions atthe 10th-order approximation of the viscous flow past a sphere. Differennt from thewell-known 2nd-order approximation of Proudman and Pearson, our approximations areuniformly valid in both near and far field of the flow, and our drag coefficient formulasagree better with experimental data in a larger region of Rernolds number.

关键词： viscous flow past a sphere analytic approximation

A whisker-like carbon composite for the immobilization of laccase and its bioelectrochemistry

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science china Chemistry 2010年第6期53卷 1332-1336页

作者： MA GuoXian1,2,ZHONG QingDong2 & LU TianHong3 1Department of Chemical engineering,shanghai Institute of Technology,shanghai 200233,china 2school of materials science and engineering,shanghai university,shanghai 200072,china 3Department of Chemistry,Nanjing Normal university,Nanjing 210097,china Department of Chemical engineering Shanghai Institute of Technology Shanghai China school of materials science and engineering Shanghai University Shanghai China Department of Chemistry Nanjing Normal University Nanjing China

A novel mesoporous carbon/whisker-like carbon (MCWC) composite was used for the immobilization of laccase (Lac) and its bioelectrochemical behaviors were *** was confirmed by XPS that Lac was strongly adsorbed on the surface of the MCWC *** cyclic voltammetric results showed that the immobilized Lac underwent a direct quasi-reversible electrochemical *** value of the electron transfer rate constant ks was estimated to be 0.770 s-1,indicating a reasonably fast electron transfer between the immobilized Lac and the underlying *** surface concentration (I-) of Lac was estimated to be 2.730 × 10-12 mol/*** experimental results showed that the immobilized Lac displayed an appreciable electrocatalytic activity to the electrochemical reduction of *** properties could be attributed to the particular structure of loosely packed nanometer-scale carbon whiskers and the existence of a large amount of oxygen-containing *** immo- bilization method and the novel carrier (MCWC) may find new applications in fabricating the biocatalysts for biofuel cells.

关键词： laccase whisker-like carbon composite direct electrochemical reaction oxygen bioelectrochemistry

SURFACE MESH PARAMETERIZATION WITH NATURAL BOUNDARY

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Chinese Journal of Mechanical engineering 2003年第3期16卷 264-267页

作者： Ye MingZhu XiaofengWang Chengtaoschool of Mechanical engineering,shanghai jiaotong university,shanghai 200030, china school of Mechanical engineering Shanghai Jiaotong University 上海 200030

Using the projected curve of surface mesh boundary as parameter domainborder, linear mapping parameterization with natural boundary is realized. A fast algorithm forleast squares fitting plane of vertices in the mesh boundary is proposed. After the mesh boundary isprojected onto the fitting plane, low-pass filtering is adopted to eliminate crossovers, sharpcorners and cavities in the projected curve and convert it into an eligible convex parameter domainboundary. In order to facilitate quantitative evaluations of parameterization schemes, threedistortion-measuring formulae are presented.

关键词： Parameterization Convex combination mapping Harmonic mapping Dirichletenergy

Analysis of Intel-metallic Phases Formed on Surface Vapor Oxidized H13 Hot Work Steels in Molten Aluminum

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材料热处理学报 2004年第5期 1299-1303页

作者： WANG Rong, WU Xiao-chun, MBS Yong-an school of materials science and engineering, shanghai university, shanghai, china

In this paper, the author dipped surface vapor oxidized H13 steel specimens into 700 °C molten aluminum liquid for a certain period of time. Analyze the intermetallic phases formed on the H13 samples surface with optical microscope and X-ray diffraction method. The observation of immersion test sample’s cross-section shows that Fe3O4 film will protect die substrate from molten aluminum erosion. The identification of the intermetallic phases reveals that they consist of 2 parts, which is named as the composite layer and the compact layer. Further investigations are made in order to know the phase constituents of the 2 layers, they are A18Fe2Si (outer composite layer), (AlCuMg) and A15Fe2 (compact layer), respectively. The experimental results show that on the same specimen, a convex surface with bigger radius of curvature is more likely to be molten and the melting loss speed is also faster than a flat and smooth surface. The thickness of compact layer on a smooth surface is much bigger than that of the convex surface. Therefore, the author supposes the compact layer is favorable in stabilizing the die surface material from further melting loss, as their formation on the die surface, the melting loss speed will decrease.

关键词： soldering melting loss HI3 steel aluminum die casting intermetallic phases

SEMANTIC NETWORK PRESENTATION OF MECHANICAL MOTION SCHEME AND ITS MECHANISM TYPES SELECTION METHOD

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Chinese Journal of Mechanical engineering 2004年第2期17卷 253-256页

作者： Ye Zhigang Zou Huijun Zhang Qing Tian Yongli school of Mechanical engineering,shanghai jiaotong university,shanghai 200030, china school of Mechanical engineering Shanghai Jiaotong University 上海 200030

The presentation method of the mechanical motion scheme must support thewhole process of conceptual design. To meet the requirement, a semantic network method is selectedto represent process level, action level, mechanism level and relationships among them. Computeraided motion cycle chart exploration can be realized by the representation and revision of timecoordination of mechanism actions and their effect on the design scheme. The uncertain reasoningtechnology based on semantic network is applied in the mechanism types selection of the needledriving mechanism of industrial sewing mechanism, and the application indicated it is correct,useful and advance.

关键词： Semantic network Scheme design Closeness degree Motion cycle chart Mechanical motion scheme

Effect of Polypropylene Fibers on the Long-term Tensile Strength of Concrete

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Journal of Wuhan university of Technology(materials science) 2007年第1期22卷 52-55页

作者：姚武 school of materials science and engineering Tongji University

The influence of low volume fraction of polypropylene（PP） fibers on the tensile properties of normal and high strength concretes was studied. The experimental results indicate that the addition of PP fibers in concrete leads to a reduction in tensile strength during the age of 28 d. Whereas, after 28 days, there is a notable effect in tensile strength due to PP fibers restraining the formation and growth of microcracks in concrete, which improves the continuity and integrality of concrete structure, Thus, a low volume fraction of PP fibers is beneficial to enhancing the long-term tensile strength of concrete materials and improving the durability of concrete structures.

关键词： polypropylene fiber concrete tensile strength microcrack

Preparation,Characterization and Visible Light Photocatalytic Activity of Nitrogen-doped TiO_2

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Journal of Wuhan university of Technology(materials science) 2006年第4期21卷 71-77页

作者：王正鹏 school of Environmental science and engineering Shanghai Jiao Tong UniversityShanghai 200240China

The N-doped TiO2 polycrystalline powder was synthesized through calcining the hydrolysis prodact of tetra-butyl titanate with ammonia. The photocatalytic activity of N-doped TiO2 powder with anatase phone calcined at 400℃ was 2.7 times higher than that of Degussa P25 for phenol decomposition under visible light. All samples had mesoporoas structures. X- ray photoelectron spectroscopy confirmed that a trace amount of N atoms remained in the anatase polycrystaUine TiO2 powder when calcined at 400 ℃ as substitutional atoms at the oxygen sites. UV-Vis and EPR analyses indicated that oxygen vacancy states were created during the course of N-doped TiO2 powder formation. It is considered that substitutional N atoms, oxygen vacancy, states, large BET surface areas and mesoporoas structure are important facwrs for the N-doped photocatalyst to present a high vis-activity.

关键词： photocatalyst visible Light nitrogen-doped TiO2 phenol

A STEEL MATRIX WEAR RESISTANT COMPOSITE REINFORCED BY IN-SITU GRANULAR EUTECTICS

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Acta Metallurgica Sinica(English Letters) 2001年第2期14卷 79-84页

作者： Z.M. Xu, T.X. Li and J.G. Li (school of materials science and engineering, shanghai Jiao Tong university, shanghai 200030, china) Sch. of Mat. Sci. and Eng. Shanghai Jiaotong Univ. Shanghai 200030 China

A new steel matrix wear resistant composite reinforced by in situ granular eutectics can be obtained by modifying with a Si-Ce-Ti compound in the steel melt. The result indicates that the in situ granular eutectic is a pseudo-eutectic of austenite and (Fe,Mn)3C, which is formed between austenite dendrites during solidification due to the segregation of C and Mn impelled by modifying elements. The quantity of in situ granular eutectic reaches up to 8%-12% and its grain size is in the range from 10um to 20um. The austenite steel matrix wear resistant composite reinforced by in situ granular eutectic (abbreviated AGE composite) and austenite-bainite steel mains wear resistant composite reinforced by in situ granular eutectic (abbreviated ABGE composite) are obtained in the as-cast state and by air hardening, respectively. The wear resistance of the AGE and ABGE composites can be more greatly increased than that of their matrix steels under low and medium impact working condition.

关键词： steel matrix composite Si-Ce-Ti compound in situ granular eutectic mechanical property

OPTIMIZING LAYOUT OF URBAN STREET CANYON USING NUMERICAL SIMULATION COUPLING WITH MATHEMATICAL OPTIMIZATION

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Journal of Hydrodynamics 2006年第3期18卷 345-351页

作者： WANG Jia-song ZHAO Bao-qing YE Chun YANG De-qing HUANG Zhen school of Mechanical and Power engineering Shanghai Jiaotong University Shanghai 200030 China school of Naval Architecture Ocean and Civil Engineering Shanghai Jiaotong University Shanghai 200030China

Optimizing the layout of the urban street canyon to achieve the maximum environmental benefits should become a new idea for modem urban street design and planning. This paper aims to find out the optimized street canyon from a viewpoint of environmental protection by using the two-dimensional numerical simulation model with the κ-ω turbulence model, coupling with the mathematical optimization method. The total pollutant concentration within and at top of the specific street canyons was taken as the objective function, and the height of one side of the canyon as the constrained condition. A nonlinearly improved constrained variable metric solver was used. The effect of the height of the leeward building and windward building on the integrated pollutant dispersion was studied to achieve the most beneficial configuration of the urban geometry. The optimization of layout for an asymmetrical street canyon was obtained. It is further found that the step-down street canyon with a large height difference is generally a good layout favoring to reduce the concentration accumulation in the street canyon.

关键词： street canyon mathematical optimization numerical simulation street layout