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Ferroelectric properties of Bi_(3.4)Ho_(0.6)Ti_3O_(12. thin films prepared by sol-gel method

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Science china(Technological Sciences) 2008年第9期51卷 1439-1444页

作者： FU ChengJu1, HUANG ZhiXiong1, LI Jie2.& GUO DongYun3 1 school of Materials Science and technology, Wuhan {2. of technology, Wuhan 430070, china 2.school of mechanical engineering, chongqing {2. of Science and technology, chongqing 400050, china 3 Department of Physics, Wuhan {2., Wuhan 430072. china school of Materials Science and technology Wuhan University of Technology Wuhan China school of mechanical {2. Chongqing University of Science and Technology Chongqing China Department of Physics Wuhan University Wuhan China

We have prepared the Ho-substituted bismuth titanate (Bi3.4Ho0.6Ti3O12. BHT) thin films on Pt/Ti/SiO2.Si substrates using sol-gel method. The crystal structure and morphology of the films were characterized using X-ray diffraction and atomic force microscopy. The BHT film shows a single phase of Bi-layered Aurivillius structure and dense microstructure. The 2.r and 2.c of the 600-nm-thick BHT film were 38.4 μC/cm2.and 376.1 kV/cm, respectively at applied electric field 500 kV/cm. The dielectric constant and dielectric loss are about 310 and 0.015 at a frequency of 1 MHz, respectively. The Pr value decreased to 93% of its pre-fatigue values after 4.46×109 switching cycles at 1 MHz frenquency, and the BHT film shows good in-sulating behavior according to the test of leakage current.

关键词： Bi3.4Ho0.6Ti3O12 thin film sol-gel method ferroelectric property fatigue dielectric constant

Effects of compressing and remelting in SIMA processing on semi-solid structure evolution of an Al-Zn wrought alloy

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Rare Metals 2003年第3期22卷 185-191页

作者： LIUChangming ZOUMaohua CollegeofmechanicalEngineedng ChongqingUniversityChongqing400044China CollegeofPolytechnic ChongqingUniversityChongqing400044China

Structure evolution of an Al-Zn wrought alloy in remelting processing in thestrain induced melt activated (SIMA) serai-solid procedure was observed, and effects of factors, theremelting temperature, the holding time, and the compression strain, on structures and grain sizesof the alloy were investigated. The results show that (1) the proper temperature of remelting is inthe range of 610 to 615℃; (2. the grain size in specimen with greater compression strain is smallerthan that with smaller compression strain in condition of the same remelting temperature andholding time, and the grain size in local area with great local equivalent strain is smaller thanthat with small one; (3) liquid occurs in form of cluster in matrix during remelting and itsquantity increases with remelting time increasing; liquid in specimen with great compression strainoccurs earlier than that with small one, and quantity of liquid in the center of specimen withgreater local equivalent strain is greater than that in the two ends of it; (4) distortion energyafter deforming in matrix of the alloy is the significant factor to activate melting of matrix atlocal area with great local equivalent strain.

关键词： semi-solid structure evolution strain induced melt activated processing semi-solid remelting Al-Zn alloy

RESEARCH OF DYNAMIC CHARACTERIATIC FOR TRANSMISSION SYSTEM

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Chinese Journal of mechanical engineering 2001年第1期14卷 74-77页

作者： Qin Shuren school of mechanical {2.,chongqing university 重庆大学机械学院重庆

The kinetic precision of transmission chain is a key problem in the research of gear cutting machine transmission *** traditional point of view is to consider the transmission chain as a geometrical meshing system,thus it is deemed that the kinetic precision of the transmission chain only depends on the manufacturing and assembly errors of its transmission *** further research reveals that the kinetic precision of transmission system is closely related with the system dynamic ***,from the dynamic point of view,it is discerned that not only deems the transmission chain as a geometrical meshing system but also considers it as a dynamic system performing with torsional *** the basis of analyses and processes of measuring data of samples from tests of cutting machine's kinetic precision of transmission chain,the results represent that the influences of dynamic characteristics of the transmission system on its kinetic precision is non *** methods for discerning the transfer function of torsional vibration of gear transmission system and experimental results have been given.

关键词： Dynamic characteristics Gear Transmission system

Mechanism of zonal disintegration in surrounding rock mass around deep rock engineering and its application

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Science china(Technological Sciences) 2011年第S1期54卷 221-227页

作者： ZHANG YongXing & ZHANG BoHu school of Civil engineering,{2. university,{2. 400045,china school of Civil engineering Chongqing University Chongqing China

The mechanical behaviors of deep rock mass are different from those of shallow rock *** cases of Jinping II Hydropower Station,the special phenomenon of zonal disintegration in the surrounding rock mass around the diversion tunnels,is *** the basis of fracture mechanics,a new strength criterion for deep rock mass is *** new nonlinear strength criterion that is relative to the rock mass rating classification can be applied to the study of the tensile failure of deep rock ***,zonal disintegration model is established,and the radius of fractured zone and none-fractured zone of deep surrounding rock mass around cylindrical tunnel are obtained,their exact positions and the evolution law of zonal disintegration of surrounding rock mass is *** validate the present model,comparison between calculation results and the experiment observation on facture and failure around underground openings is carried *** is found that the numerical simulation result is in good agreement with the experimental one on failure modes around the *** sensitivity analysis,the effects of stress condition,cohesion and the angle of internal friction on the phenomenon of zonal disintegration are ***,the present model is adopted in the analysis of the zonal disintegration in the surrounding rock mass around the diversion tunnels in Jinping II Hydropower ***,the magnitude and distributions of fractured zones are determined by numerical simulation.

关键词： deep rock mass zonal disintegration strength criteria of deep rock mass numerical simulation

Effects of scandium addition on microstructure and mechanical properties of ZK60 alloy

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Progress in Natural Science:Materials International 2011年第1期21卷 59-65页

作者： Fu-sheng PAN~(1,2.,Ting-ting LIU~(1,2.,Xi-yan ZHANG~(1,2.,Ai-tao TANG~(1,2.,Wei-qing WANG~(1,2. 1.National engineering Research Center for Magnesium Alloys,chongqing {2.,chongqing 400045,china 2.College of Materials Science and engineering,chongqing {2.,chongqing 400045,china National engineering Research Center for Magnesium Alloys Chongqing University Chongqing 400045 China College of Materials Science and engineering Chongqing University Chongqing 400045 China

The effects of Sc addition on the microstructure and mechanical properties of the ZK60 wrought magnesium alloy were investigated by using optical microscope,scanning electron microscopy,X-ray diffraction and tensile *** experimental results show that a minor Sc addition to ZK60 alloy has an obvious effect on the refinement of the microstructure of the ZK60 alloy. During hot extrusion,incomplete dynamic recrystallization occurs in all the alloys,and the recrystallized grains become much finer with increasing Sc *** tensile strengths of ZK60 evidently increase with the addition of Sc,but the elongations decrease. The ZK60 alloy with 0.6%(mass fraction) Sc addition is found to have the tensile strength of about 350 MPa and the yield strength of about 2.0 *** T6 heat treatment,the tensile strength of the alloy containing 0.6%Sc remains almost ***, the yield strength of the alloy increases up to 352.MPa,and the ratio of the tensile strength to the yield strength is close to 1.

关键词： wrought magnesium alloy scandium microstructure mechanical properties

Effect of Preparation Methods on mechanical Properties of PVA/HA Composite Hydrogel

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Journal of Bionic engineering 2010年第3期7卷 235-243页

作者： Dekun Zhang~1, Junjie Duan~1, Dagang Wang~2. Shirong Ge~2.1. school of Materials Science and engineering,{2. university of Mining and technology Xuzhou 2.1116, P. R.{2. 2. school of mechanical and Electrical engineering,{2. university of Mining and technology, Xuzhou 2.1116, P. R.{2. school of Materials Science and engineering China University of Mining and Technology Xuzhou P. R. China school of mechanical and Electrical {2. China University of Mining and Technology Xuzhou P. R. China

Poly(vinyl alcohol) (PVA)/hydroxyapatite (HA) composite hydrogel specimens were prepared with 15% PVA and 1%,2., 3%, 4% and 5% HA by repeated freezing-thawing. The tests of static and dynamic mechanical properties were carried out todiscuss the influence of different contents of HA and freezing-thawing cycles on the mechanical properties of PVA/HA compositehydrogel. The results of static mechanical tests showed that the PVA/HA composite hydrogel with 3% HA and ninefreezing-thawing cycles had excellent stress relaxation properties, higher relaxation ratio, lower stress equilibrium value andpresented better properties of creep and recovery. The results of dynamic mechanical test showed that the PVA/HA compositehydrogel with nine freezing-thawing cycles had higher storage modulus and loss modulus, so was the PVA/HA compositehydrogel with 3% HA.

关键词： composite hydrogel HA contents freezing-thawing cycles static properties dynamic properties

Kinetics analysis of volume phase transition of intelligent neutral thermo-sensitive hydrogels

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Science china(Physics,Mechanics & Astronomy) 2008年第5期51卷 532-540页

作者： WANG XiaoGui1 & LI YiQuan2.1 College of mechanical engineering,Zhejiang {2. of technology,Hangzhou 310032.china 2.school of mechanical & Electronic engineering,Changchun {2. of Science and technology,Changchun 13002.,china College of mechanical engineering Zhejiang University of Technology Hangzhou China school of mechanical & Electronic {2. Changchun University of Science and Technology Changchun China

In this work,utilizing the first law of thermodynamics and the Flory mean-field theory,the kinetic deformation studies concerning the volume phase transition of the neutral thermo-sensitive hydrogels were performed *** hydrogel was assumed as a biphasic mixture medium in the framework of the continuum mixture *** the energy conservation of the thermodynamics system of the hydrogel,the governing equations for the kinetics of the nonlinear large deforma-tion were *** explicit analytical expressions of the effective stress tensor and the chemical potential of the fluid of the thermo-sensitive hydrogel PNIPA were also obtained from the Helmholtz free energy,which can model the steady-static volume phase transition quantitatively.

关键词： thermo-sensitive hydrogel volume phase transition effective stress energy conservation

Grain refinement of Mg-Li-Al cast alloys by adding typical master alloys

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Progress in Natural Science:Materials International 2011年第3期21卷 236-239页

作者： Bin JIANG~(1,2.,Qing-shan YANG~2.Ming-xing ZHANG~3,Dong QIU~3,Rui-hong LI~2.Fu-sheng PAN~(1,2. 1.National engineering Research Center for Magnesium Alloys,chongqing {2.,chongqing 400044,china 2.College of Materials Science and engineering,chongqing {2.,chongqing 400044,china 3.Division of Materials,school of mechanical and Mining engineering, The {2. of Queensland,St Lucia,QLD 4072.Australia National engineering Research Center for Magnesium Alloys Chongqing University Chongqing 400044 China College of Materials Science and engineering Chongqing University Chongqing 400044 China Division of Materials School of Mechanical and Mining Engineering The University of Queensland St Lucia QLD 4072 Australia

Commercial Al-3Ti-1C and Al-5Ti-1B master alloys were added in order to refine the grains of Mg-Li-Al *** effects of their addition levels on grain refinement of Mg-Li-Al cast alloy were investigated and the mechanism of the grain refinement was *** results showed that the addition of Al-3Ti-1C master alloy reduced the grain size of LA141 cast alloy from 900μm to 400μm,while the addition of Al-5Ti-1B master alloy reduced the grain size of LA51 cast alloy from 500μm to 2.0μ*** grain refining mechanism was the heterogeneity nucleation of TiC and TiB2.because of less than 10%mismatches of TiC/β-Li and TiB2.α-Mg.

关键词： magnesium lithium alloy master alloy grain refinement

Electrically Conductive Concrete for Heating Using Steel Bars as Electrodes

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Journal of Wuhan university of technology(Materials Science) 2010年第3期25卷 523-526页

作者：侯作富 school of mechanical {2. Yangtze University

The steel bars with good electrical conductivity were used as two kinds of electrodes in the making of carbon fiber（CF） electrically conductive concrete for *** results of the pertinent experiments illustrate the design is *** change in electrical resistivity over three years＇ hydration time was studied when steel bars were used as lateral face electrodes and top bottom surface electrodes *** temperature rise test was conducted to verify the heating properties of two kinds of *** only the study can reduce the CF volume content of electrically conductive concrete for heating to 0.58% or 0.36% according to different design,but also it will enhance the carrying capacity of the concrete roadway for heating.

关键词： steel bar carbon fiber electrical resistivity temperature rise