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Numerical simulation of the transient multiphase field during plasma deposition manufacturing composite materials

Science China(Physics,Mechanics & Astronomy) 2009年第4期52卷 508-517页

作者： KONG FanRong1,2,ZHANG HaiOu1 & WANG GuiLan3 1 State Key Laboratory of Digital manufacturing Equipment and Technology,Huazhong university of Science and Technology,Wuhan 430074,China 2 research center for advanced manufacturing,southern methodist university,3.01 dyer street,dallas,texas 75205,usa 3 College of Material Science and Engineering,Huazhong university of Science and Technology,Wuhan 430074,China 1. State Key Laboratory of Digital manufacturing Equipment and Technology Huazhong University of Science and Technology Wuhan 430074 China 2. research center for advanced manufacturing Southern Methodist University 3101 Dyer Street Dallas Texas 75205 USA 3. College of Material Science and Engineering Huazhong University of Science and Technology Wuhan 430074 China

A solid/liquid/gas unified model has been developed to investigate the gradient composition formation during the plasma deposition manufacturing(PDM) composite materials process. In this model,an enthalpy porosity model was applied to deal with the melting and solidification of the deposited layer,and a level-set approach was introduced to track the evolution of the free surface of the molten pool and the deposited layer. Moreover,complicated physical phenomena occurring at the liquid/gas interface,including forced convection heat loss,heat emission and plasma heat source,have been incorporated into the governing equations by source terms. In this study,the numerical experiment of nickel base alloy powder deposited on the medium steel substrate by PDM technique was implemented based on the staggered grid and SIMPLEC algorithm. Concentration gradient distribution of the solute material at the composite material interface,fluid flow and temperature distribution in the molten pool and the deposited layer have been investigated in detail.

关键词： plasma deposition manufacturing composite material solid/liquid/gas unified model level-set approach

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Keyhole Double-Sided Arc Welding Process

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Journal of Materials Science & Technology 2001年第1期17卷 159-160页

作者： Yuming ZHANG Shaobin ZHANG and bang JIANG Welding research Laboratory, center for Robottes and manufacturing Systems, university of Kentucky, Lexington, Kentucky 40506, usa. Lin WU National Key Laboratory for advanced Welding Production Technology, Harbi Univ Kentucky Ctr Robot & Mfg Syst Welding Res Lab Lexington KY 40506 USA Harbin Inst Technol Natl Key Lab Adv Welding Prod Technol Harbin 150001 Peoples R China

In the proposed method, the current/arc is guided through the keyhole so that the energy of the plasma jet is compensated while it is consumed in heating the workpiece along the keyhole. As a result, deep narrow penet... 详细信息

关键词： Arc Keyhole Double-Sided Arc Welding Process Zhang

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Online application of automatic surface quality inspection system to finishing line of cold rolled strips

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Journal of university of Science and Technology Beijing 2003年第4期10卷 38-41页

作者： Hao Sun, Ke Xu, and Jinwu XuNational Engineering research center of advanced Rolling, university of Science and Technology Beijing, Beijing 100083, China National Engineering research center of advanced Rolling. university of Science and Technology Beijing Beijing 100083 China

An automatic surface quality inspection system installed on a finishing lineof cold rolled strips is introduced. The system is able to detect surface defects on cold rolledstrips, such as scratches, coil breaks, rusts, roll imprints, and so on. Multiple CCD area scancameras were equipped to capture images of strip surface simultaneously. Defects were detectedthrough 'Dark-field illumination' which is generated by LED illuminators. Parallel computationtechnique and fast processing algorithms were developed for real-time data processing. Theapplication to the production line shows that the system is able to detect defects effectively.

关键词： surface inspection cold rolled strip finishing line CCD cameras imageprocessing

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Nano-scale Interfacial Friction Behavior between Two Kinds of Materials in MEMS Based on Molecular Dynamics Simulations

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Journal of Wuhan university of Technology(Materials Science) 2006年第4期21卷 173-176页

作者：杨平 research center of Micro-Nano Science and Technology Jiangsu University Zhenjiang 212013ChinaResearch Center of Advanced Design & Manufacturing Guilin Institute of Electronic Technology Guilin 541004 China

The aim of this article was to provide a systematic method to perform molecular dynamics simulotion or evaluation for nano-scale interfacial friction behavior between two kinds of materials in MEMS design. Friction is an important factor affecting the performance and reliability of MEMS. The model of the nano-scale interracial friction behavior between two kinds of materials was presented based on the Newton＇ s equations of motion. The Morse potential function was selected for the model. The improved Verlet algorithm was employed to resolve the model, the atom trajectories and the law of the interfacial friction behavior. Comparisons with experimental data in other paper confirm the validity of the model. Using the model it is possible to simulate or evaluate the importance of different factors for designing of the nano-scale interfacial friction behavior between two kinds of materials in MEMS.

关键词： molecular dynamics simulation interfacial friction nano-scale friction MEMS

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Effect of Heating Rate Before Tempering on Reversed Austenite in Fe-9Ni-C Alloy

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Journal of Iron and Steel research International 2012年第9期19卷 73-78页

作者： ZHANG Kun , TANG Di , WU Hui-bin ( National Engineering research center of advanced Rolling , university of Science and Technology Beijing , Beijing 100083 , China ) National Engineering research center of advanced Rolling University of Science and Technology Beijing Beijing 100083 China

The alloy was reheated to 580℃ for tempering at rates of 2 , 5 , 10 , 20 , and 40℃ / s , respectively , after *** amount , distribution , and stability of reversed austenite were investigated by X-ray diffraction ( XRD ) and electron back scatter diffraction ( EBSD ) .The microstructure and cryogenic impact energy were studied by scanning electron microscope ( SEM ), transmission electron microscope ( TEM ) and Charpy V-notch ( CVN ) *** results showed that when the sample was heated at 10℃ / s , the volume fraction of reversed austenite exhibited maximum of 8% ; the reversed austenite was uniform along all kinds of boundaries ; the reversed austenite contained higher concentration of carbon which enabled it to be more *** cryogenic toughness of the alloy was greatly improved when heated at 10℃ / s , as the fracture surface observation showed that it mainly fractured in ductile rupture mode , which was consistent with the results of cryogenic impact energy.

关键词： 9Ni steel heating rate reversed austenite cryogenic toughness

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Local segment-shared protection based on source egress gateway selection for multi-domain optical mesh networks

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Science China(Information Sciences) 2011年第2期54卷 227-235页

作者： ZHANG ShengFeng1,3, PENG YunFeng1,2, DU Shu1, YANG XiaoLong1,2 & LONG KePing1,2 1research center for Optical Internet and Mobile Information Networks, university of Electronic Science and Technology of China, Chengdu 611731, China 2Institute of advanced Network Technology and New Serives (ANTS), university of Science and Technology Beijing, Beijing 100083, China 3research center for Optical Internet Networks, Chongqing university of Posts and Telecommunications, Chongqing 400065, China 1. research center for Optical Internet and Mobile Information Networks University of Electronic Science and Technology of China Chengdu 611731 China3. Research Center for Optical Internet Networks Chongqing University of Posts and Telecommunications Chongqing 400065 China2. Institute of Advanced Network Technology and New Serives (ANTS) University of Science and Technology Beijing Beijing 100083 China

Survivability for multi-domain optical networks is becoming a key parameter due to expanding network. In order to provide the shared-path-protected lightpath in multi-domain optical mesh networks, we propose a protection solution, called GSLSSP. A new source egress gateway selecting mechanism is adopted in this solution. For each connection request, this mechanism can enable the source node to select a better egress gateway node to the destination domain and compute one inter-domain working path near the optimal path with the cooperating of this gateway node, under scalability and domain privacy constraint of multi-domain networks. And then one intra-domain link-disjoint local segment-backup path for each working-segment path is computed out in each single-domain passed by the working path. Simulation evaluation shows that the proposed scheme can provide 100% protection ability for multiple failures. Besides, it is effective in multi-domain path protection with more efficient resource utilization, lower blocking probabilities and less inter-domain cost than other schemes.

关键词： survivability optical mesh networks multi-domains multiple failures segment-shared protection

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Effects of temperature and pressure on the structural and optical properties of ZnO films grown by pulsed laser deposition

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Science China(Technological Sciences) 2010年第2期53卷 317-321页

作者： ZHAO Lei, XU ChangShan, LIU YuXue & LIU YiChun center for advanced Opto-Electronic Functional Materials research, Northeast Normal university, Changchun 130024, China 1. center for advanced Opto-Electronic Functional Materials research Northeast Normal University Changchun 130024 China

ZnO thin films were deposited on fused silica via pulsed laser deposition (PLD) at substrate temperatures from 300°C to 800°C and ambient oxygen pressures ranging from 10-2 mTorr to 240 mTorr. X-ray diffraction (XRD) and Raman spectra indicated that wurtzite ZnO was obtained in all cases. The highly c-oriented ZnO films were obtained for oxygen pressures above 11 mTorr. The room-temperature photoluminescence (PL) spectra demonstrated that all the films exhibited strong near-band-edge (NBE) emission, while deep-level (DL) emission was also observed in films deposited at oxygen pressures below 80 mTorr. From analysis of the XRD, Raman and photoluminescence PL data, an optimal condition was identified for the deposition of highly crystallized ZnO films.

关键词： zinc oxide film pulsed laser deposition optical properties

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Pleonaste in Boxian meteorite

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Chinese Science Bulletin 1998年第19期43卷 1656-1660页

作者： WANG Kuiren and HONG Ji’an Department of Earth and Space Sciences, university of Science and Technology of China advanced research center for Earth Sciences and Astronomy, university of Science and Technology of China, Third World Academy of Sciences Department of Earth and Space Sciences University of Science and Technology of China China advanced research center for Earth Sciences and Astronomy University of Science and Technology of China Third World Academy of Sciences Hefei China

There are three kinds of occurrence of pleonaste, a rare meteoritic mineral, totally found in Boxian meteorite. They are as the following: (ⅰ) occurring in the inner circle of the chondrule edge, of which a circle texture is composed; (ⅱ) occurring in the state of inclusions, included in an olivine chondrule, with close paragenesis of wadsleyite; (ⅲ) occurring in the state of porphyry. The chondrule in the first occurrence belongs to CA chondrules. The chemical compositions of pleonaste are heterogeneity except for the atomic ratios of Fe/(Mg+Fe), which can be attributed to the following reasons: (ⅰ) they are congenetic minerals; (ⅱ) the heterogeneity of the compositions of the solar clouds in the early states; (ⅲ) the chondrites are the multiple-stage evolution; (ⅳ) the further proof of Boxian meteorite is an unequilibrium common chondrite.

关键词： rare pleonaste in meteorites found genesis.

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Stability of linear discrete switched systems with delays based on average dwell time method

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Science China(Information Sciences) 2010年第6期53卷 1216-1223页

作者： WANG Yong 1 , WANG Wei 1 & LIU GuoPing 2,3 1 research center of Information and Control, Dalian university of Technology, Dalian 116024, China 2 Faculty of advanced Technology, university of Glamorgan, Pontypridd, CF37 1DL, UK 3 CTGT center in Harbin Institute of Technology, Harbin 150001, China 1. research center of Information and Control Dalian University of Technology Dalian 116024 China2. Faculty of Advanced Technology University of Glamorgan Pontypridd CF37 1DL UK3. CTGT Center in Harbin Institute of Technology Harbin 150001 China

This paper deals with the problem of exponential stability for a class of linear discrete switched systems with constant *** switched systems consist of stable and unstable *** on the average dwell time method, some switching signals will be found to guarantee exponential stability of these *** explicit state decay estimation is also given in the form of the solutions of linear matrix inequalities(LMIs).An example relating to networked control systems(NCSs) illustrates the effectiveness of the proposed method.

关键词： switched systems average dwell time time delay LMI

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Integral ear elimination and virtual point-based updating algorithms for constrained Delaunay TIN

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Science China(Technological Sciences) 2008年第S1期51卷 135-144页

作者： WU LiXin1,2,WANG YanBing2,3 & SHI WenZhong2,4 1 Institute for Geo-informatics & Digital Mine research,Northeastern university,Shenyang 110004,China 2 Institute for GIS/RS/GPS & Subsidence Engineering research,China university of Mining & Technology,Beijing 100085,China 3 Laboratory of 3D Information Acquisition & Application,Capital Normal university,Beijing 100037,China 4 center for advanced GIS research,LSGI,Polytechnic university Hong Kong,Hong Kong,China Northeastern Univ Inst Geoinformat & Digital Mine Res Shenyang 110004 Peoples R China China Univ Mining & Technol Inst GIS RS GPS & Subsidence Engn Res Beijing 100085 Peoples R China Capital Normal Univ Lab Informat Acquisit & Applicat Beijing 100037 Peoples R China Hong Kong Polytech Univ LSGI Ctr Adv GIS Res Hong Kong Hong Kong Peoples R China

Constrained Delaunay Triangular Irregular Networks (CD-TIN),a kind of special data structure,have many practical applications in Geoinformatics,especially in the representation of linear constrained triangulation for DTM and DSM,such as in digital city and digital mine. Past researches on D-TIN mainly focused on point in-sertion and deletion without consideration of constraint,and that on CD-TIN usu-ally paid more attention to the insertion algorithms for points and edges,but little to the deletion algorithms. The presented algorithms are far insufficient for the dy-namic updating of CD-TIN. In this paper,the constraint edge in CD-TIN is consid-ered to be any set of broken lines,i.e.,polygon edges,broken lines and simple segments. The constraint edge may be composed of one or more constraint seg-ments,and it is allowed to be in any form: Open or close,intersection or self-in-tersection. By improving to present insertion and deletion algorithms for D-TIN,two new algorithms for CD-TIN updating are presented. According to the polymorphism of the constraints in CD-TIN,virtual point is adopted to represent the crossing node between constraint edges when a constraint edge is inserted in CD-TIN. Two new algorithms named as Integral Ear Elimination (IEE) and Influence Domain Retrian-gulation for Virtual Point (IDRVP) are presented,the former is for constraint point deletion,while the later is for the insertion and deletion of constraint edge. The principle of IDRVP is that to divide the influence domain of a virtual point into some parts by the constraint-keeping edges,and to retriangulate each part of the influ-ence domain individually referring to the constraint visible property and constraint empty circle (CEC) criterion. Finally,a prototype system is developed with VC++,one case on the integration of 3D terrain and buildings is demonstrated to test the correctness of new algorithms. It shows that the new algorithms are effective for the updating of CD-TIN.

关键词： Delaunay TIN spatial constraint data updating spatial modeling polymorphism digital mine

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