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Search Results: 1 - 10 of 45684 matches for " YUAN Chang-Lai "
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Fabrication and Properties of the Potassium Sodium Niobate/Cobalt Copper Ferritemultiferroic Magnetoelectric Composites
XUAN Min-Jie, LIU Xin-Yu, YUAN Chang-Lai, XU Ji-Wen, MA Jia-Feng
无机材料学报 , 2012, DOI: 10.3724/sp.j.1077.2012.12014
Abstract: (1–x)(0.9462K0.5Na0.5NbO3-0.0498LiSbO3-0.004BiFeO3)-xCo0.85Cu0.15Fe2O4((1–x)(KNN-LS-BFO)-xCCFO) (x=0.1, 0.2, 0.3, 0.4, 0.5) multiferroic magnetoelectric ceramics were prepared by solid phase method. The presence of perovskite and spinel in the sintered composites were proved by XRD patterns and no impurity phase existed. SEM images show that particle size of KNN-LS-BFO is big and complete, while the particle size of CCFO is small. When x increases from 0.1 to 0.5, the piezoelectric coefficient of the composites decreases from 120 pC/N to33 pC/N, While saturation magnetization and remanent magnetization increase and saturation magnetostriction constant increases from 18×10–6 to 52×10–6 approximately. When the applied magnetic field increases, the magnetoelectric properties of the composites increase to the maximum and then decrease. When the alternating magnetic field frequency is 1 kHz and x=0.3, the magnetoelectric voltage coefficient attains maximum value 20.6 mV/A.
Study on the microstructures and electrical properties of Bi0.5Ba0.5Fe0.5Ti0.49Nb0.01O3 thermistor ceramic

Yuan Chang-Lai,Liu Xin-Yu,Ma Jia-Feng,Zhou Chang-Rong,

物理学报 , 2010,
Abstract: 采用固相合成工艺,制备了Bi0.5Ba0.5Fe0.5Ti0.49Nb0.01O3(BBFTN)热敏陶瓷,借助X射线衍射仪、扫描电子显微镜、阻温测试仪和交流阻抗谱考察其微结构、直流电阻、介电特性、阻抗和电学模量方面的电学性能. 结果表明:BBFTN材料依然为立方钙钛矿结构,平均晶粒尺寸约为1.0 μm,晶格常数相对于BaTiO3的晶格常数有所变大;室温电
Preparation and Magnetoelectric Coupling Effects of Ba0.85Ca0.15Zr0.1Ti0.9O3/CoFe2O4 Laminated Ceramics
YUAN Chang-Lai, XUAN Min-Jie, XU Ji-Wen, LIU Xin-Yu, ZHOU Chang-Rong, YANG Yun
无机材料学报 , 2013, DOI: 10.3724/sp.j.1077.2013.12236
Abstract: The Ba0.85Ca0.15Zr0.1Ti0.9O3-CoFe2O4 laminated composite ceramics composed of the piezomagnet CoFe2O4, and the piezoelectrics Ba0.85Ca0.15Zr0.1Ti0.9O3 with the sintering agents CuO and CeO2, were prepared by the interfacial solid-state melt infiltration technique. It is found that a good interfacial bonding between the piezomagnet and piezoelectrics is obtained. With the increasing thickness ratio of piezomagnet to piezoelectrics, the magnetostriction coefficient (–λ) of the laminated ceramics increase, the piezoelectric coefficient (d33) decrease, and the magnetoelectric coupling coefficient (αE) increases firsty and then decreases. The values of –λ and d33 of the laminated ceramics are in the range from 67×10-6 to 134×10-6 and 205 pC/N to 340 pC/N, respectively. At dc magnetic field of 100 mT along with ac frequency of 230 kHz and the thickness ratio of 2, a maximum value of αE=3200 mV/(cm·mT) is achieved for the laminated ceramics.
Preparation and Properties of Sm2O3 Doped (Ba0.7Ca0.3)TiO3-Ba(Zr0.2Ti0.8)O3 Lead-free Piezoelectric Ceramics
CUI Ye-Rang, LIU Xin-Yu, YUAN Chang-Lai, ZHAI Xia, HU Yao-Bin, LI Ruo-Wen
无机材料学报 , 2012, DOI: 10.3724/sp.j.1077.2012.11517
Abstract: Sm2O3 doped (Ba0.7Ca0.3)TiO3-Ba(Zr0.2Ti0.8)O3 (BCZT) lead-free piezoelectric ceramics were prepared by solid state synthesis method. The microstructure and electrical properties of prepared ceramics were investigated by XRD, SEM and other techniques. The results demonstrate that Sm2O3 doping reduces sintering temperature of BCZT lead-free piezoelectric ceramics and increases the Curie temperature Tc from 85 o 95 BCZT ceramics doped with 0.02wt%-0.1wt% Sm2O3 possess a typical ABO3 type perovskite structure.With the doping of 0.02wt% Sm2O3, the BCZT ceramics show the optimum electrical properties, and its piezoelectric constant d33, electromechanical coupling factor kp, mechanical quality factor Qm, dielecteic loss tanδ and relative dielectric constant εr reach 590 pC/N, 0.52, 43, 1.3% and 3372, respectively.
Electrical Properties of CuO―doped SrFe0.9Sn0.1O3― δ Thick Film NTC Thermistors
YUAN Chang-Lai,WU Xiu-Fang,LIU Xin-Yu,HUANG Jing-Yue,LI Bo,LIANG Mei-Fang,MO Chong-Gui
无机材料学报 , 2011, DOI: 10.3724/sp.j.1077.2011.00387
Abstract: CuO―doped SrFe0.9Sn0.1O3― δ (CSFS) thick―film negative temperature coefficient (NTC) thermistors ( 20mol%, 30mol%, 40mol%, 50mol% ) were prepared by the screen printing method. The microstructures and electrical prop erties of CSFS thick films were determined. With the increase of CuO content, the surface morphology of thick films becomes denser. The room―temperature resistance values gradually decreases to about 0.46 M Ω and the thermistor― constant values are basically constant at around 3300 K. After the addition of CuO, SrFe0.9Sn0.1O3― δ is decomposed into various SrFe1― xSn xO3― δ ( 0.1< x<1 ) phases. By two― RQ series equivalent circuit model, impedance characteristics of the thick film containing 40mol% CuO content are investigated over the measured temperature range of 25–250 It is found that the total thick―film resistance is mainly attributed to the contribution of grain and grain boundary resistances, both of which show the typical NTC thermistor characteristics. Furthermore, the complete match of peak frequencies between the imaginary parts of impedance and electric modulus suggests that delocalized conduction is the main conduction mechanism in the thick―film NTC thermistors.
Electrical properties and impedance analysis of Bi0.5Ba0.5FeO3 ceramic

Yuan Chang-Lai,Liu Xin-Yu,Huang Jing-Yue,Zhou Chang-Rong,Xu Ji-Wen,

物理学报 , 2011,
Abstract: 以传统的固相反应法制备了Bi0.5Ba0.5FeO3陶瓷,并采用X射线衍射仪、扫描电子显微镜、直流阻温测试仪和交流阻抗分析仪测试了Bi0.5Ba0.5FeO3陶瓷的微结构和电性能.分析结果表明:Bi0.5Ba0.5FeO3陶瓷具有立方钙钛矿结构,颗粒尺寸约1.0μm;在16—280℃范围内,Bi0.5Ba0.5FeO3陶瓷表现出明显的负温度系数热敏效应,其热敏常数、活化能分别为6490K及0.558eV;介电温谱揭示,在280℃下Bi0.5Ba0.5FeO3陶瓷材料没有出现相变行为.对于交流阻抗谱,采用3个串联的RQ(R与Q为并联)等效部件来拟合分析,拟合结果表明拟合数据与实验数据高度匹配,且这3个等效部件分别代表晶界、晶粒和晶壳的贡献.3个部件中,晶粒对陶瓷电阻阻值的影响最大,晶壳贡献次之,晶界最小,且3个部件电阻值都显示出负温度系数效应.在25—115℃范围内,电学模量虚部峰频与阻抗虚部峰频始终不匹配,意味着Bi0.5Ba0.5FeO3陶瓷体内部一直表现出局域导电机理.
Preparation and magnetoelectric characteristics of K0.5Na0.5NbO3-LiSbO3-BiFeO3/CuFe2O4 composite ceramics

Yuan Chang-Lai,Zhou Xiu-Juan,Xuan Min-Jie,Xu Ji-Wen,Yang Yun,Liu Xin-Yu,

物理学报 , 2013,
Abstract: 采用传统的固相法制备了(1-x)(K0.5Na0.5NbO3-LiSbO3-BiFeO3)-xCuFe2O4 (x=0.1, 0.2, 0.3, 0.4) 磁电复合陶瓷, 并借助X射线衍射仪、扫描电镜和磁电耦合系数测试仪等对复合陶瓷的微结构和性能进行了分析. 结果表明, 复合陶瓷的K0.5Na0.5NbO3-LiSbO3-BiFeO3和CuFe2O4物相之间发生了一定的离子相互扩散作用, 且两相的颗粒大小匹配性较好. 随着CuFe2O4含量增加, 复合陶瓷的压电系数从130 pC/N减小到30 pC/N, 饱和磁致伸缩系数从4.5×10-6增加到12.4×10-6左右, 磁电耦合系数表现出先增加后减小, 在x=0.3时获得最大的磁电耦合系数9.4 mV·cm-1·Oe-1.
Impedance analysis of BaFe0.4Sn0.6O3/BaBiO3 composite negative temperature coefficient ceramics

Yuan Chang-Lai,Liu Xin-Yu,Yang Yun,Xu Ji-Wen,Gu Yan,

物理学报 , 2010,
Abstract: 以BaBiO3为导电相,BaFe0.4Sn0.6O3为高阻相,采用固态反应法制备了不同BaBiO3含量的BaFe0.4Sn0.6O3/BaBiO3负温度系数(NTC)热敏复合陶瓷.为获得在渗流阈值(即BaBiO3含量为12 mol%)前后复合陶瓷的内部导电机理,对复合陶瓷进行了阻抗分析.分
Role of hyaluronic acid and laminin as serum markers for predicting significant fibrosis in patients with chronic hepatitis B
Li, Feng;Zhu, Chang-Lai;Zhang, Hong;Huang, Hua;Wei, Qun;Zhu, Xiang;Cheng, Xiao-Yang;
Brazilian Journal of Infectious Diseases , 2012, DOI: 10.1590/S1413-86702012000100002
Abstract: objectives: the aim of this study was to evaluate the diagnostic performance of serum ha and ln as serum markers for predicting significant fibrosis in chb patients. methods: serum ha and ln levels of 87 patients with chronic hepatitis b and 19 blood donors were assayed by ria. liver fibrosis stages were determined according to the metavir scoring-system. the diagnostic performances of all indexes were evaluated by the receiver operating characteristic (roc) curves. results: serum ha and ln concentrations increased significantly with the stage of hepatic fibrosis, which showed positive correlation with the stages of liver fibrosis (ha: r = 0.875, p < 0.001; ln: r = 0.610, p < 0.001). there were significant differences of serum ha and ln levels between f2-4 group in comparison with those in f0-f1 group (p < 0.001) and controls (p < 0.001), respectively. from roc curves, 185.3 ng/ml as the optimal cut-off value of serum ha for diagnosis of significant fibrosis, giving its sensitivity, specificity, ppv, npv, lr+, lr- and ac of 84.2%, 83.3%, 90.6%, 73.5%, 5.04, 0.19 and 83.9, respectively. while 132.7 ng/ml was the optimal cut-off value of serum ln, the sensitivity, specificity, ppv, npv, lr+, lr- and ac were 71.9%, 80.0%, 87.2%, 60.0%, 3.59%, 0.35% and 74.7, respectively. combinations of ha and ln by serial tests showed a perfect specificity and ppv of 100%, at the same time sensitivity declined to 63.2% and lr+ increased to 18.9, while parallel tests revealed a good sensitivity of 94.7%, npv to 86.4%, and lr- declined to 0.08. conclusions: serum ha and ln concentrations showed positive correlation with the stages of liver fibrosis. detection of serum ha and ln in predicting significant fibrosis showed good diagnostic performance, which would be further optimized by combination of the two indices. ha and ln would be clinically useful serum markers for predicting significant fibrosis in patients with chronic hepatitis b, when liver biopsy is contraindicated.
A Virtual Deadline Guided Min-Min Meta-task Scheduling Heuristic

YANG Jiang-Hu,GAO Chuan-Shan,HUANG Chang-Lai,LI Ming,

计算机科学 , 2006,
Abstract: In Grid environment which is a Heterogeneous Computing(HC) environment, resource status and user behavior are very complicated, so scheduling heuristics for meta-task are more complicated than traditional parallel scheduling heuristics. How to map a set of tasks on a set of machines is known to be NP-hard. The goal of those scheduling heuristics is minimize the makespan of the meta-tasks. Some heuristics are introduced to solve such scheduling problem, including Min-Min and other heuristics. In this paper, based on traditional Min-Min scheduling heuristic, a virtual deadline guided meta-task scheduling heuristic is proposed. The simulation results show that the proposed heuristic has less makespan than traditional Min-Min scheduling heuristic.
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