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畴极化转动对多晶铁电材料断裂特性的影响
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作者 程锦泉 王彪 杜善义 《应用数学和力学》 EI CSCD 北大核心 2002年第11期1113-1123,共11页
 主要基于细观力学方法揭示了畴极化转动对多晶铁电陶瓷的各向异性断裂特性的平均影响· 首先,用Eshelby_Mori_Tanaka理论和统计模型分析了无穷大铁电材料体中一椭球夹杂的内、外电弹性场,得到畴极化转动对电弹性场的平均影响;...  主要基于细观力学方法揭示了畴极化转动对多晶铁电陶瓷的各向异性断裂特性的平均影响· 首先,用Eshelby_Mori_Tanaka理论和统计模型分析了无穷大铁电材料体中一椭球夹杂的内、外电弹性场,得到畴极化转动对电弹性场的平均影响;其次,推导了等效多晶铁电陶瓷中含一钱币状裂纹的裂纹扩展力(能量释放率)Gext,并用它估计了畴极化转动对多晶铁电陶瓷断裂特性的影响· 对BaTiO3陶瓷中裂纹扩展力的计算结果表明,对多晶铁电材料断裂特性分析必须考虑畴极化转动的影响· 计算结果得出了与实验相一致的结论:在受较小的力时,外加电场对裂纹扩展产生较大的影响。 展开更多
关键词 极化转动 多晶铁电材料 断裂特性 闭域
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多晶铁电材料的有效电弹性能预报 被引量:2
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作者 程锦泉 王彪 杜善义 《力学学报》 EI CSCD 北大核心 1999年第3期330-338,共9页
本文利用细观力学方法———Eshelby等效夹杂法和MoriTanaka的平均场理论,根据铁电材料的微结构特点,建立了一个细观统计模型对多晶铁电材料的有效电弹性能和模量进行分析预报.在本细观统计模型中,不仅考虑到单... 本文利用细观力学方法———Eshelby等效夹杂法和MoriTanaka的平均场理论,根据铁电材料的微结构特点,建立了一个细观统计模型对多晶铁电材料的有效电弹性能和模量进行分析预报.在本细观统计模型中,不仅考虑到单晶粒的形状影响,而且考虑铁电畴在外场作用下发生极化转动的影响. 展开更多
关键词 铁电材料 极化转动 细观力学 有效电弹性能
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含随机分布缺陷的多晶铁电材料的有效电弹性能 被引量:1
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作者 程锦泉 王彪 杜善义 《力学学报》 EI CSCD 北大核心 2001年第3期407-414,共8页
针对铁电材料含有随机分布缺陷以及微结构在外场作用下发生变化的特点,建立起一个细观统计力学模型,考虑到缺陷和畴极化转动之间的相互影响,利用细观力学方法──Eshelby等效夹杂法和Mori-Tanaka的平均场理论,具... 针对铁电材料含有随机分布缺陷以及微结构在外场作用下发生变化的特点,建立起一个细观统计力学模型,考虑到缺陷和畴极化转动之间的相互影响,利用细观力学方法──Eshelby等效夹杂法和Mori-Tanaka的平均场理论,具体分析了所含缺陷以及外场对铁电材料有效电弹性能和模量的影响.针对BaTiO3铁电陶瓷的有效电弹性能与常数的预报结果表明了缺陷的存在将增强材料的压电性能. 展开更多
关键词 多晶铁电材料 随机分布缺陷 极化转动 细观力学 有效电磁性能 微结构 外场作用
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FLC编码系统中材料参量设计的电路实验研究 被引量:2
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作者 王梦遥 潘炜 +3 位作者 罗斌 张伟利 邹喜华 熊悦 《应用基础与工程科学学报》 EI CSCD 2006年第4期590-596,共7页
提出用电路模型实验的方法对铁电液晶基相位编码系统进行材料参量设计.建立了编码系统中关于相位分析的铁电液晶电路模型.以铁电液晶材料的典型参数(自发极化强度、转动粘滞系数以及液晶薄膜厚度)为参变量,给出了稳态方位角(表征外加电... 提出用电路模型实验的方法对铁电液晶基相位编码系统进行材料参量设计.建立了编码系统中关于相位分析的铁电液晶电路模型.以铁电液晶材料的典型参数(自发极化强度、转动粘滞系数以及液晶薄膜厚度)为参变量,给出了稳态方位角(表征外加电场引起的铁电液晶折射率变化)与各参变量间的依赖关系,以及各参变量对调制速率的影响.实验结果表明:调制速率随自发极化强度的提高而增加,随转动粘滞系数、液晶薄膜厚度的提高而减慢.控制自发极化强度取值大于38nC/cm3,转动粘滞系数小于210mPa.s,液晶薄膜厚度小于24μm可使稳态方位角满足基于相位编码系统提出的参考值. 展开更多
关键词 铁电液晶 相位编码 电路模型 自发极化强度:转动粘滞系数
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Converted-wave diodic moveout and application in the land gas cloud area
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作者 张四海 李向阳 戴恒昌 《Applied Geophysics》 SCIE CSCD 2011年第3期171-180,239,共11页
PS converted-waves (C-waves) have been commonly used to image through gas clouds but the C-wave imaging may also be degraded by the diodic effect introduced by the gas cloud. It may be compensated for using a veloci... PS converted-waves (C-waves) have been commonly used to image through gas clouds but the C-wave imaging may also be degraded by the diodic effect introduced by the gas cloud. It may be compensated for using a velocity perturbation method which decouples the diodic moveout into two parts: the base velocity and the velocity perturbation. Gas clouds are widely distributed in the Sanhu area in the Qaidam basin of northwest China which is rich in natural gas. A land 2D3C seismic dataset is analyzed from the Sanhu area and significant diodic effects are observed in the data which harm the C-wave imaging. The diodic correction is applied to this data and the resultant C-wave imaging and the details of the reservoir structure are significantly improved. The diodic moveout plays an important role in working out the residu~ shear wave statics and the association of diodie correction and shear wave residual statics computation is a key step of C-wave high fidelity imaging in the gas cloud area. Finally, the new process workflow with diodic moveout is given. 展开更多
关键词 Diodic converted wave gas cloud base velocity PERTURBATION
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Stereodynamics of O(^3P)+H2 at Scattering Energies of 0.5, 0.75, and 1.0 eV 被引量:2
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作者 Victor Wei-keh Wu 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2010年第2期149-154,I0001,共7页
Quasiclassical trajectory calculation of the title reaction O(^3P)+H2→OH+H at three different scattering energies of 0.5, 0.75, and 1.0 eV on the lowest electronic potential energy surface 1^3A" has been done. D... Quasiclassical trajectory calculation of the title reaction O(^3P)+H2→OH+H at three different scattering energies of 0.5, 0.75, and 1.0 eV on the lowest electronic potential energy surface 1^3A" has been done. Distribution P(θr) of polar angles between the relative velocityk of the reactant and rotational angular momentum vector j' of the product, distribution P(φr) of the azimuthal as well as dihedral angles correlating k-k'-j', 3-dimensional distri-bution, and polarization-dependent differential cross sections (PDDCSs)dependent upon the scattering angle of the product molecule OH between the relative velocity k of the reactant and k' of the product at different scattering energies of 0.5, 0.75, and 1.0 eV are presented and discussed. 展开更多
关键词 Quasiclassical trajectory calculation Stereodynamics Alignment Rotational angular momentum Polarization-dependent differential cross section O+H2 reaction
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Preparation High-Temperature Behavior of Conversion Coating of Alumina Film on FeCrAI (Ce) Stainless Steel
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作者 H. Essom 《Journal of Chemistry and Chemical Engineering》 2012年第12期1083-1092,共10页
FeCrAI (Ce) stainless steel was functionalized by a conversion treatment in order to allow alumina by diffusion coatings with strong interfacial bonding. The very porous conversion coating produced in a pack alumini... FeCrAI (Ce) stainless steel was functionalized by a conversion treatment in order to allow alumina by diffusion coatings with strong interfacial bonding. The very porous conversion coating produced in a pack aluminization technique had excellent adhesion and was conductive enough to permit conditions favorable for the precipitation of alumina oxyhydroxide during aluminum diffusion coatings. In this work, the bed was prepared as a mixture of A1, NH4C1 and A1203. In the high-activity bed were heat-treated at 1,173 K in an atmosphere made up of team with subsequent air-cooling. The effect of the bed content on the coating was examined. With the high-activity, the desired Fe2Al5 was formed as the outermost coating layer. The coating presented chemical composition gradients suitable for strong adhesion. The improvement of the thermal oxidation behaviour was studied at 1,373 K. Two different aqueous environments, which are (1) NaC1 and (2) H2SO4, are employed for using the technique of potentiodynamic polarization curve. The obtained experimental electrochemical parameters (Ecorr, Jcorr etc,) were used to compare the corrosion resistance of the tested steel state complemented by MEB (electronic scanning microscopy) in combination with dispersive analysis X in energy (EDS) or X ray diffraction indicated that the elements concentration maximum was located in the vicinity of the interface especially in the FeCrAI (Ce) coated by spherical A1203 powder. These results an discussed in terms of an addition effect on the development of the microstructure of oxide films. 展开更多
关键词 COATING ALUMINA corrosion MORPHOLOGY heat treatment adhesion.
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