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Bias voltage and properties of magnetron sputtered niobium films

Zhenkong Kexue yu Jishu Xuebao/Journal of Vacuum Science and technology 2008年第1期28卷 67-71页

作者： Cui, Jiangtao Tian, Xiubo Yang, Shiqin State Key Laboratory of Advanced Welding Production Technology School of Materials and Engineering Harbin Institute of Technology Harbin 150001 China Shenzhen Key Lab. of Composite Materials Shenzhen-Tech-Innovation International Shenzhen 518057 China

Niobium films were grown by DC magnetron sputtering on CrNi3Mo steel substrates. Its microstructures and mechanical properties were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and conventional probes. The results show that the negative bias voltages significantly affect its surface morphology and its mechanical properties. For example, at a bias of 150 V, the compact film has the highest erosion-resistance.

关键词： Magnetron sputtering

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Effect of welding speed on the material flow patterns in friction stir welding of AZ31 magnesium alloy

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Rare Metals 2007年第2期26卷 158-162页

作者： ZHANG Hua Wu Huiqiang Huang Jihua LIN Sanbao WU Lin Materials Science and Engineering School University of Science and Technology Beijing Beijing 100083 China Beijing Institute of Astronautical Systems Engineering Beijing 100076 China State Key Lab of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China

The clear zigzag-line pattern on transverse cross sections can be used to explain the formation mechanism of the weld nugget when friction stir welded AZ31 magnesium alloy without any other insert material is used as mark. It provides a simple and useful method to research the joining mechanism of friction stir welding. The rotation speed is kept at 1000 r/min and the welding speed changes from 120 mm/min to 600 mm/min. The macrostructure on the transverse cross section was divided into several parts by faying surface. The results show that the shape and formation procedure of the weld nugget change with the welding speed. There are two main material flows in the weld nugget： one is from the advancing side and the other is from the retreating side. A simple model on the weld nugget formation of FSW is presented in this article.

关键词： AZ31 magnesium alloy friction stir welding faying surface materials flow formation model

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Growth and properties of pulsed laser deposited K3Li2Nb5O15 thin films

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key engineering Materials 2007年 351卷 184-188页

作者： Zhan, Zusheng Gong, Yansheng Shen, Qiang Zhang, Lianmeng State Key Lab. of Advanced Technology for Material Synthesis and Processing Wuhan University of Technology Wuhan 430070 China School of Materials Science and Chemical Engineering China University of Geosciences Hubei Wuhan 430074 China

Potassium lithium niobate (KLN: K3Li2Nb5O15) films have been deposited on quartz glass by Pulsed laser deposition (PLD) technique using a stoichiometric KLN target as starting materials. By investigating the effects of both the oxygen pressure and the substrate temperature on the structure of KLN films, optimum parameters have been identified for the growth of high-quality KLN films. At 10Pa oxygen ambient pressure, tetragonal tungsten-bronze-type structure of KLN films with (310) preferred orientation can be achieved at substrate temperatures in the range of 700-800°C Optical studies indicate that the films are highly transparent in the visible-near-infrared wavelength range.

关键词： Thin films

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Unsymmetrical Quantum key Distribution Using Tripartite Entanglement

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Communications in Theoretical Physics 2007年第3期47卷 441-445页

作者： XIONG Jin ZHANG Zhe-Shen ZHOU Nan-Run PENG Jin-Ye ZENG Gui-Hua State Key Lab of Advanced Optical Communication Systems and Networks Department of Electronic Engineering Shanghai Jiao Tong University Shargghai 200240 China School of Information Science and Technology Northwest University Xi＇an 710069 China

An unsymmetrical quantum key distribution protocol is proposed, in which Greenherger-Horne-Zeilinger （GHZ） triplet states are used to obtain the secret key. Except the lost qubits due to the unperfectness of the physical devices, the unsymmetrical characteristic makes all transmitted qubits useful. This leads to：an excellent efficiency, which reaches 100% in an ideal case. The ＇security is studied from the aspect of information theory. By using the correlation of the GHZ tripartite entanglement state, eavesdropping can be easily checked out, which indicates that the presented protocol is more secure.

关键词： unsymmetrical quantum key distribution GHZ triplet states

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Reaction process of Al2(1-x)MgxTi1+xO 5 composite powder by chemical co-precipitation and subsequent sintering

Reaction process of Al2(1-x)MgxTi1+xO 5 composite powder by ...

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作者： Shen, Shang-Yue Yang, Rui Shen, Qiang Wang, Chuan-Bin Zhang, Lian-Meng School of Materials Science and Chemical Engineering China University of Geosciences Wuhan 430074 China State Key Lab. of Advanced Technology for Materials Synthesis Processing Wuhan University of Technology Wuhan 430070 China

Al2(1-x)MgxTi1+xO5(x=0.05-0.3) composite powder was prepared by the method of chemical coprecipitation and subsequent sintering using TiCl5, MgCl2 and AlCl 3 solution as the raw materials, and ammonia and ammonium carbonate as the solvent. Thermal dynamics and kinetic dynamics analysis of the precursor during the heat treatment were explored in detail, and the reaction process of Al2(1-x)MgxTi1+xO5(x=0.3) composite powder was confirmed. Results show that, as the temperature increases MgO reacts with TiO2 of anatase phase to form MgTi2O5. At about 650°C, anatase transfers into rutile. Then MgTi2Os reacts with Al2O3 to produce MgAl2O4 at 900°C. When the temperature is above 1100°C, the desired Al 2(1-x)MgxTi1+xO5(x=0.3) composite powder is synthesized by the reaction of MgAl2O24, Al 2O3 and TiO2 of rutile phase.

关键词： Powders

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Preparation and property of self-dispersed nanometer γ-AlOOH

Preparation and property of self-dispersed nanometer γ-AlOO...

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作者： Liao, Haida Wu, Bolin Zhang, Lianmeng Liao, Donghua Wang, Huixian State Key Lab. of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China Manning China Guilin China College of Chemistry and Ecological Engineering Guangxi University for Nationalities Nanning 530006 China Department of Materials and Chemical Engineering Guilin University of Technology Guilin China

A peptizing-hydrothermal method to prepare nanometer γ-AlOOH crystal powder with industrial Al(OH)3 as raw materials has been proposed in the present paper. The XRD and TEM results show the product is a pure γ type nanometer A100H crystal powder with average grain diameter of 70nm. Laser grading analysis indicates the average grain diameters of the product in the solution are 66.52nm in water and 84.33nm in N,N-dimethylformamide, respectively without surface modification and dispersant. The experimental result indicated that polymer/inorganic nano-composite with high content of nanometer AlOOH presents inorganic characteristic of polymer. The wear rate of the alumina ceramic ball sintered at 1465°C from ceramic, which contains 98% alumina (wt), can be reduced up to 40% with addition of 3.5% nanometer AlOOH.

关键词： Hydrothermal synthesis

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Time on the performance of ceramic ball grinding media prepared from refractory waste

Time on the performance of ceramic ball grinding media prepa...

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作者： Zhong, L.Y. Wu, B.L. Zhang, L.M. Song, J.G. State Key Lab. of Advanced Technology for Materials Synthesis and Processing Wuhan University of Technology Wuhan 430070 China Key Lab. of Nonferrous Materials and New Processing Technology Guilin University of Technology Ministry of Education Guilin Guangxi 541004 China Department of Materials and Chemical Engineering Guilin University of Technology Guilin 541004 China

Aluminosilicate refractory waste was used to prepare high performance ceramic ball grinding media with 75% Al2O3. The influence of milling time on the particle size of raw materials, the sintering temperature, and performance of ceramic balls were studied. Results show that with increasing milling time the particle size of the raw materials decreased, resulting in a decrease of ceramic ball sintering temperature and an increase in wear resistance and volume density. The wear rate and volume density of balls prepared by milling the materials for 72 h were 0.01886 %/h and 3.374 g/cm 3, respectively.

关键词： Grinding (machining)

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Transmission Properties of Radar Wave through Reentry Plasma Sheath

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Journal of Electronic Science and technology of China 2007年第1期5卷 29-32,37页

作者：高正平马兆国刘静李仲平张大海 Engineering Research Center of Electromagnetic Wave Absorbing Materials Ministry of EducationUniversity of Electronic Science and Technology of China State Key Lab. of Electronic Thin Films & Integrated Devices University of Electronic Science and Technology of China Chengdu 610054 China National Key Laboratory of Advanced Functional Composite Materials 9200 Box

In this paper, by taking into account the coupling of the ionization of ablation gas and atmosphere, an electrons density distribution model is built. Using this model, the transmission properties of different polarization radar wave through sheath are evaluated on the basis of the transmission matrix theory. Then, we discuss the effects of the electrons density, the added magnetic field, and the radar wave frequency on the transmission properties. As a result of this investigation, greater transmission power could be gained in order to efficiently shorten communication blackout, by reducing the electrons density or choosing proper added magnetic field and the frequency of the radar wave according to the different polarization form of the radar wave.

关键词： communication blackout plasma sheath radar wave reentry transmigsion properties

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Transmission Properties of Radar Wave through Reentry Plasma Sheath

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Journal of Electronic Science and technology 2007年第1期000卷 29-32,37页

作者： GAO Zheng-ping MA Zhao-guo LIU Jing LI Zhong-ping ZHANG Da-hai Engineering Research Center of Electromagnetic Wave Absorbing Materials Ministry of Education University of Electronic Science and Technology of China State Key Lab. of Electronic Thin Films & Integrated Devices University of Electronic Science and Technology of China Chengdu 610054 China Engineering Research Center of Electromagnetic Wave Absorbing Materials Ministry of Education National Key Laboratory of Advanced Functional Composite Materials 9200 Box Chengdu 610054 China Beijing 100076 China

In this paper,by taking into account the coupling of the ionization of ablation gas and atmosphere,an electrons density distribution model is built. Using this model,the transmission properties of different polarization radar wave through sheath are evaluated on the basis of the transmission matrix theory. Then,we discuss the effects of the electrons density,the added magnetic field,and the radar wave frequency on the transmission properties. As a result of this investigation,greater transmission power could be gained in order to efficiently shorten communication blackout,by reducing the electrons density or choosing proper added magnetic field and the frequency of the radar wave according to the different polarization form of the radar wave.

关键词： communicationblackout plasmasheath radarwave reentry transmissionproperties

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Evolution of Cu/Al Intermetallic Compounds in the Copper Bump bonds during Aging Process

Evolution of Cu/Al Intermetallic Compounds in the Copper Bum...

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第八届电子封装技术国际会议(2007 8th International Conference on Electronics Packaging technology ICEPT2007)

作者： Chunqing Wang Yanhong Tian Chunjin Hang Y.Zhou Microjoining Lab State Key Lab of Advanced Welding Production Technology Harbin Institute of Techn Microjoining Lab State Key Lab of Advanced Welding Production Technology Harbin Institute of Techn Microjoing Lab Department of Mechanical Engineering University of Waterloo Canada N2L 3G1

Growth of Cu/Al intermetallic compounds (IMCs) at the interface between the copper bond and the Al metallization pad would increase the contact resistance and degrade the bond reliabilities. In this study, the thermosonic copper bump bonds were aged at 250 ℃ for 1 to 196 hours. Then the evolution of Cu/Al IMCs was investigated. Three IMC layers with different colors were found at the Cu/Al interface using the optical microscopy on the xy plane cross-section of the ball bond. The main phases in the Cu/Al IMC are confirmed to be Cu9Al4, and CuAl2. CuAl is believed to be another phase in the copper bond. During the aging process, Cu/Al IMC grew from the periphery of the bond initially and propagated inward to the centre area later. Moreover, some cavities appeared between the IMC layer and bond bottom from the bond periphery and developed into the centre area.

关键词： Copper Intermetallic Aging Bonding Gold Wire Metallization Aluminum Temperature Welding

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