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Study on the microstructures and electrical properties of Bi0.5Ba0.5Fe0.5Ti0.49Nb0.01O3 thermistor ceramic
Bi0.5Ba0.5Fe0.5Ti0.49Nb0.01O3热敏陶瓷的微结构和电学性能研究

Yuan Chang-Lai,Liu Xin-Yu,Ma Jia-Feng,Zhou Chang-Rong,<br>,刘心宇,马家峰,
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
QoS-based scheduling heuristics for dependent tasks in grid computing
网格环境下基于QoS需求的关联任务调度算法*

JIANG Li-li,JIANG Chang-jun,YUAN Lu-lai,<br>姜黎立,,
计算机应用研究 , 2008,
Abstract: 首先描述QoS调度问题,建立QoS需求模型;然后通过分析任务的依赖性,提出时间花费、资源价格和可靠性三种QoS参数的映射机制;最后针对网格环境的新特征,提出一种以优化用户效用为目标,基于QoS的关联任务调度算法(QBDTS_UO).仿真实验结果表明,该算法能以较小的时间花费为代价,有效满足用户的QoS需求,并能大大提高网格资源的使用率.
Electrical properties and impedance analysis of Bi0.5Ba0.5FeO3 ceramic
Bi0.5Ba0.5FeO3陶瓷的电性能及阻抗分析

Yuan Chang-Lai,Liu Xin-Yu,Huang Jing-Yue,Zhou Chang-Rong,Xu Ji-Wen,<br>,刘心宇,黄静月,,许积文
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.
Ca0.6La0.8/3TiO3-Li0.5Sm0.5TiO3复合微波陶瓷的介电性能
杨 云,陈国华,,
硅酸盐学报 , 2014, DOI: 10.7521/j.issn.0454-5648.2014.04.05
Abstract: 采用传统固相合成法制备了xCa0.6La0.8/3TiO3-(1-x)(Li0.5Sm0.5)TiO3(CLT-LST)系列微波介质陶瓷材料,研究了该系列微波介质陶瓷的物相结构、表面形貌、介电性能。实验发现随着Ca0.6La0.8/3TiO3含量的增多,CLT-LST样品XRD峰轻微左移。陶瓷组成对微波介电性能影响显著,复合体系CLT--LST的微波介电性能随着x值不同而连续变化当x从0.2上升到0.6时,介电常数(εr)逐步增大,在x=(0.4~0.6),εr变化趋于稳定,达到较佳值;品质因数(Q·f)则先减小后增大再迅速减小;谐振频率温度系数(τf)逐渐从负值向正值方向移动。当复合体系组成为0.4Ca0.6La0.8/3TiO3-0.6(Li0.5Sm0.5)TiO3时,在1250℃烧结4h所得到的微波介电性能较佳,εr=125;Q·f=2680GHz;τf=7.0×106/℃。
Preparation and magnetoelectric characteristics of K0.5Na0.5NbO3-LiSbO3-BiFeO3/CuFe2O4 composite ceramics
K0.5Na0.5NbO3-LiSbO3-BiFeO3/CuFe2O4复合陶瓷的制备与磁电性能研究

Yuan Chang-Lai,Zhou Xiu-Juan,Xuan Min-Jie,Xu Ji-Wen,Yang Yun,Liu Xin-Yu,<br>,周秀娟,轩敏杰,许积文,杨云,刘心宇
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
BaFe0.4Sn0.6O3/BaBiO3负温度系数复合热敏陶瓷阻抗分析

Yuan Chang-Lai,Liu Xin-Yu,Yang Yun,Xu Ji-Wen,Gu Yan,<br>,刘心宇,杨云,许积文,谷岩
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
boldmath Characterization of the BaBiO3-doped BaTiO3 positive temperature coefficient of a resistivity ceramic using impedance spectroscopy with Tc=155℃
,刘心宇,,许积文,杨云
中国物理 B , 2011,
Abstract: BaBiO3-doped BaTiO3 (BB-BT) ceramic, as a candidate for lead-free positive temperature coefficient of resistivity (PTCR) materials with a higher Curie temperature, has been synthesized in air by a conventional sintering technique. The temperature dependence of resistivity shows that the phase transition of the PTC thermistor ceramic occurs at the Curie temperature, Tc=155 ℃, which is higher than that of BaTiO3 ( ≤ 130 ℃). Analysis of ac impedance data using complex impedance spectroscopy gives the alternate current (AC) resistance of the PTCR ceramic. By additional use of the complex electric modulus formalism to analyse the same data, the inhomogeneous nature of the ceramic may be unveiled. The impedance spectra reveal that the grain resistance of the BB-BT sample is slightly influenced by the increase of temperature, indicating that the increase in overall resistivity is entirely due to a grain-boundary effect. Based on the dependence of the extent to which the peaks of the imaginary part of electric modulus and impedance are matched on frequency, the conduction mechanism is also discussed for a BB-BT ceramic system.
BaBiO3掺杂BaFe0.4Sn0.6O3负温度系数热敏电阻的电学性能
,刘心宇,杨云,轩敏杰,
硅酸盐学报 , 2011,
Abstract: 用传统固态反应法制备多晶(1-x)BaFe0.4Sn0.6O3-xBaBiO3(0.05
Sexual reproductive structures of Latest Proterozoic multicellular rhodophytes (red algae) from South China
ZHANG Yun,<br>张昀,
中国科学C辑(英文版) , 1996,
Abstract: Carposporangium- and spermatangium-like reproductive structures associated with differentiated vegetative tissues have been observed in the multicellular rhodophyte fossils, which were well preserved in the 650-Ma-old phosphate rocks of Doushantuo Formation in Guizhou Province, South China. The fossils show details of cellular structures that are comparable to the female and male reproductive organs of some extant rhodophytes. The first fossil-histological evidence for sexuality of Precambrian non-vascular plants is provided.
Bi4B2O9对(Ca0.2Sr0.05Li0.375Sm0.375)TiO3陶瓷烧结和微波介电性能的影响
刘 飞,王子兴,,彭福伟,陈国华,蒙柳方
硅酸盐学报 , 2014, DOI: 10.7521/j.issn.0454-5648. 2014. 12.15
Abstract: 采用传统固相法制备(Ca0.2Sr0.05Li0.375Sm0.375)TiO3钙钛矿微波介质陶瓷,研究了Bi4B2O9对(Ca0.2Sr0.05Li0.375Sm0.375)TiO3陶瓷微波介电性能的影响,利用X射线衍射仪、扫瞄电子显微镜和矢量网络分析仪对其晶体结构、显微组织和微波介电性能进行了研究。结果表明掺10%Bi4B2O9的(Ca0.2Sr0.05Li0.375Sm0.375)TiO3陶瓷,其烧结温度由1300℃降至1080℃。当添加3.5%Bi4B2O9时,其最佳烧结温度为1150℃,陶瓷的微波介电性能最佳(相对介电常数εr=116.9;品质因数Q×f=3500GHz;频率温度系数τf=1.2×10-6/℃)。
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