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The characteristics of arc beam shaping in hybrid plasma and laser deposition manufacturing

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science{1.(Technological sciences) 2006年第2期49卷 238-247页

作者： zhang Hai’ou1, QIAN Yingping1,3, wang Guilan1 & ZHENG Qiguang2.1. {2. of Material science and technology, Huazhong university of science and technology, wuhan 430074, china 2. Institute of Laser technology and Engineering, Huazhong university of science and technology, wuhan 430074, china 3. Mechanical Engineering College, hubei university of technology, wuhan 430068, china 1. school of Material {1. and {2. Huazhong University of Science and Technology Wuhan 430074 China 3. Mechanical Engineering College Hubei University of Technology Wuhan 430068 China 2. Institute of Laser {1. and Engineering Huazhong University of Science and Technology Wuhan 430074 China

As a new direct metal prototyping technology,the hybrid plasma and laser deposition manufacturing (PLDM) is proposed in this paper. In order to figure out the characteristics of plasma arc beam and mould in the PLDM process of high temperature alloy, the high speed CCD camera is used to obtain the picture around the plasma arc. Afterwards the sketch of picture is clearly obtained. And the effect of laser parameter, such as average power, pulse width, pulse repetition frequency and the angle between laser beam and plasma arc beam on the plasma arc appearance, is studied experimentally. The results show that the modality of plasma arc beam is markedly influenced by laser beam. And the improvements of shape precision and surface state of the layer deposited by PLDM are confirmed.

关键词： plasma hybrid laser, direct deposition, plasma arc beam, molding character, high-temperature alloy.

A study of two-dimensional magnetic polaron

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science{1.(Physics,Mechanics & Astronomy) 2006年第4期49卷 421-429页

作者： LIU Tao1, zhang Huaihong1, FENG Mang1,2.& wang Kelin1,3 1. {2. of science, Southwest university of science and technology, Mianyang 62.010, china 2. wuhan Institute of Physics and Mathematics, Chinese Academy of sciences, wuhan 430070, china 3. Department of Modern Physics, university of science and technology of china, Hefei 2.002., china school of {1. Southwest University of Science technology Mianyang 621010 China wuhan Institute of Physics Mathematics Chinese Academy of Sciences Wuhan 430070 China Department of Modern Physics University of Science technology of{1. Hefei 230026 China

By using the variational method and anneal simulation, we study in this paper the self-trapped magnetic polaron (STMP) in two-dimensional anti-ferromagnetic material and the bound magnetic polaron (BMP) in ferromagnetic material. Schwinger angular momentum theory is applied to changing the problem into a coupling problem of carriers and two types of Bosons. Our calculation shows that there are single-peak and multi-peak structures in the two-dimensional STMP. For the ferromagnetic material, the properties of the two-dimensional BMP are almost the same as that in one-dimensional case; but for the anti-ferromagnetic material, the two-dimensional STMP structure is much richer than the one-dimensional case.

关键词： self-trapped magnetic polaron, bound magnetic polaron, impurity potential, anti-ferromagnet.

Accountability Analysis of Electronic Commerce Protocols by Finite Automaton Model

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wuhan {1. Journal of Natural {2.s 2004年第3期9卷 293-295页

作者： Xie Xiao-yao 1,2., zhang Huan-guo 1 1. school of {2., wuhan university, wuhan 430072. hubei, china 2. Institute of Network technology, Guizhou university of technology, Guiyang 550003, Guizhou, china wuhan {1. School of Computer Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***) Guizhou university of {1. Institute of Network Technology Guiyang Guizhou China (GRID:grid.443382.a) (ISNI:***) wuhan {1. School of Computer Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***)

The accountability of electronic commerce protocols is an important aspect to insures security of electronic transaction. This paper proposes to use Finite Automaton (FA) model as a new kind of framework to analyze the transaction protocols in the application of electronic commerce. Key words finite automaton - electronic commerce - nonrepudiation - information security CLC number TP 393. 08 Foundation item: Supported by the National Natural science Foundation of{1. (66973034, 901.4005, 60373087)Biography: Xie Xiao-yao (1.52.), male, Professor, Ph. D candidate, research direction: information security.

关键词： finite automaton electronic commerce nonrepudiation information security

Flame-retardant Mechanism of Magnesium Oxychloride in Epoxy Resin

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Journal of wuhan {1. of {2.(Materials science) 2009年第1期24卷 127-131页

作者：秦麟卿 State Key Laboratory of Advanced technology for Materials Synthesis and Processing Wuhan University of Technology Center for Material Research and Analysis Wuhan University of Technology

Flame-retardant mechanism of magnesium oxychloride （M OC） in EP was in-vestigated by limiting oxygen index （LOI）, XRD, SEM, TG-DTG and DSC. The results show that MOC performed well as an inorganic flame-retardant in EP. When the content of MOC is 50%, the LOI of EP reaches {1..6% and mass of residual char reaches 9.6%. The flame retarde mechanism of MOC is due to the synergies of diluting, cooling, catalyzing char forming and obstructing effects.

关键词： magnesium oxychloride epoxy resin flame-retardant properties flame retardedmechanism

Synthesis, Characterization and Flame-retardant Properties of Epoxy Resins and AACHH Composites

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Journal of wuhan {1. of {2.(Materials science) 2009年第5期24卷 763-767页

作者：秦麟卿 State Key Laboratory of Advanced technology for Materials Synthesis and Processing Wuhan University of Technology

Flame retardant epoxy resins were prepared by a simple mixed method using ammonium aluminum carbonate hydroxy hydrate （AACHH） as a halogen-free flame retardant. The prepared samples were characterized by X-ray diffraction, thermogravimetric and differential scanning calorimetry, scanning electron microscope and limiting oxygen index（LOI） experiments. Effects of AACHH content on LOI of epoxy resins/AACHH composite and flame retardant mechanism were investigated and discussed. Results show that AACHH exhibites excellent flame-retardant properties in epoxy resin（EP）. When the content of AACHH was 47.4%, the LOI of EP reached 3{1.{1.. Moreover, the initial and terminal decomposition temperature of EP increased by 48 ℃ and 40 ℃, respectively. The flame retarded mechanism of AACHH is due to the synergic flame retardant effects of diluting, cooling, decomposition resisting and obstructing.

关键词： epoxy resin(EP) flame retardant ammonium aluminum carbonate hydroxy hydrate (AACHH) composite

Toughening Modification of Unsaturated Polyester Resin Using HDI Trimer

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Journal of wuhan {1. of {2.(Materials science) 2009年第4期24卷 627-630页

作者：段华军 school of Materials {1. and Engineering Wuhan University of Technology

HDI trimer was firstly used to improve the mechanical properties of hydroxyl-terminated unsaturated polyester （UP）. Mechanical properties measurements performed on the cured materials demonstrate a distinct improvement in intensity and toughness in the presence of HDI trimer and shows the change trends of increase and then decrease. The morphological analysis of the fracture surfaces shows that the micro-phase separated structures appear in modified UPR systems and changed from dendritric, dimple and to cystiform structures with the increase of HDI trimer content. The presence of the cystiform structures made the modified UPR systems present the best properties.

关键词： HDI trimer unsaturated polyester toughness mechanical properties morphology

Research on Alkaline Filler Flame-Retarded Asphalt Pavement

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Journal of wuhan {1. of {2.(Materials science) 2006年第3期21卷 146-148页

作者：胡曙光 school of Materials {1. and Engineering Wuhan University of Technology Wuhan 430070China

Used as flame returdant of tunnel asphalt pavement, organic bromides produce a large amount of poisons and smoke in construction and flame retardation stage. The alkaline filler was found to replace mineral filler, and the flame- retarded asphalt mixtures were produced. Experimental results show that these asphalt mixtures are smoke restrained ; the performances and construction technology of asphalt pavement are not influenced; also the alkaline filler is of low-price. So this kind of flame-retarded asphalt mixtures is suitable for tunnel patement.

关键词： alkaline filler flame-retarded asphalt mixture limited oxygen index tunnel

Effect of Sintering Aid CuO-MnO_2.on Dielectric Properties of 0.5Ba(Mg_(1.3)Nb_(2.3))O_3-0.5Ba(Ni_(1.3)Nb_(2.3))O_3 Ceramics

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Journal of wuhan {1. of {2.(Materials science) 2009年第1期24卷 123-126页

作者：田中青 school of Materials {1. and Engineering Chongqing Institute of Technology

Microstructures and microwave dielectric properties of 0.5Ba（Mg1.3Nb2.3）O3-0.5Ba（Ni1.3Nb2.3）O3 ceramics with x wt% CuO-x wt% MnO2.additions （x=0.2.-1. prepared by conventional solid-state route were investigated. It is found that low level-doping of CuO-MnO2.can significantly improve the density of the specimens and their microwave dielectric properties. The relative density of 0.5Ba（Mg1.3Nb2.3）O3-0.5Ba（Ni1.3Nb2.3）O3 ceramics can be increased by 95% sintering at 1.330 ℃ due to the liquid phase effect. The second phase is not observed in ceramics with CuO-MnO2.addition. The parameterεr increases with increasing sintering temperature, and Qf is effectively promoted by CuO-MnO2.addition. Higher CuO-MnO2.content would make τf value more positive. Meanwhile, εr value of 30.5, Qf value of 63 2.0 GHz and τf value of 0.5 ppm/ ℃ were obtained for 0.5Ba（Mg1.3Nb2.3）O3-0.5Ba（Ni1.3Nb2.3）O3 ceramics with 0.5 wt% CuO-0.5 wt% MnO2.addition sin-tered at 1.330 ℃ for 4 h.

关键词： ceramics oxides X-ray diffraction dielectric properties

A New Secure Password Authentication Scheme Using Smart Cards

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wuhan {1. Journal of Natural {2.s 2008年第6期13卷 739-743页

作者： wang Bangju1,2. wang Yuhua3, {2. Huanguo1 1. school of computer, wuhan university/Key Laboratory of Aerospace Information Security and Trust Computing of Ministry of Education, wuhan 430072. hubei, china 2. school of {12., Huazhong Agricultural university, wuhan 430070, hubei, china 3. College of Information {12. and Engineering, Henan university of technology Zhengzhou 450001, Henan, china school of Information {1. and {2. Southwest Jiaotong University Chengdu 610031 Sichuan China

Thirteen security requirements for an ideal password authentication scheme using smart cards are listed and a new smart card based password authentication scheme with identity anonymity is proposed. The new scheme can satisfy all the listed ideal security requirements and has the following merits：（1. it can resist all the attacks listed in introduction; （2. less storage memory requirement due to no verification table stored in server; （3） low computational cost due to hash functions based operations; （4） even if the smart card is lost, the new system is still secure; （5） As user identity is anonymous, this scheme is more practical. The new proposed scheme can be applied in source constraint networks.

关键词： password password authentication hash function attack smart card