排序方式: 共有9条查询结果,搜索用时 16 毫秒
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以钛酸丁酯和金属盐酸盐为原料,采用溶胶-凝胶工艺制备了CoFe2O4/TiO2复合薄膜,分析了不同热处理温度对复合薄膜晶粒生长及薄膜表面形貌的影响.通过XRD射线、拉曼光谱、扫描电子显微镜、偏光显微镜对薄膜热分解中物相变化过程及其表面形貌进行了观测,用振动样品磁强计(VSM)测定了样品的磁性.实验结果表明:溶胶-凝胶法制得的复合薄膜,两相组分晶体各自析出长大,CoFe2O4组分均匀地分布在TiO2基体中,随着热处理温度的升高,薄膜的磁性增强. 相似文献
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采用传统固相烧结工艺, 结合特殊的气氛控制技术,制备了铌酸钾钠(KNN)基无铅透明陶瓷 xBa(Sc0.5Nb0.5)O3-(1-x) (K0.5N0.5)NbO3 (简写xBSN-(1-x)KNN). 并对其微观结构、介电、铁电性能和光学透光率进行了研究. 结果表明该体系陶瓷具有准立方钙钛矿结构, 没有其他杂相, 晶粒大小与可见光波长相当, 高度致密, 无明显的晶界存在. 在 x=0.05时, d33最高可达到110 pC/N, 2Pr达到25.4 μC/cm2. 同时该材料具有良好的透明性, 在可见光范围内,透过率达到54%左右, 近红外2500 nm处,透过率接近83%, 是一种有望取代铅基透明陶瓷的环境友好型无铅透明陶瓷. 相似文献
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研究了等静压对0.75Pb(Mg1/3Nb2/3)O3-0.25PbTiO3(PMN-25PT)陶瓷介电温谱的影响,PMN-25PT剩余极化随等静压变化和等静压压致相变.结果表明,随着压力增加,PMN-25PT的介电峰值温度Tm降低,/+{dTm}/-{dP}≈-4℃/kbar,极化弛豫增强;剩余极化随压力增加连续减小;介电常数对压力的依赖关系与对温度场的依赖相似,压力诱导PMN-25PT发生弛豫铁电—顺电相变,相变为宽化的渐变过程,频率色散和极化弛豫更加强烈和普遍.
关键词:
铌镁酸铅-钛酸铅
等静压
介电弛豫
压致相变 相似文献
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This paper reports that a general method of designing
invisible cloaks is using variant constitutive material
parameters to realize the space transformation. A hollow region can
be hidden after this transformation. It was recently shown (Ma H, Qu
S B, Xu Z and Wang J F 2009 \wx{Appl. Phys. Lett.}{94} 103501) that
when the original point moves to the boundary of a cloak, the cloak
can be designed to be open. Based on this theory, we propose
multi-window invisible cloaks which can conceal a group of objects.
Full wave simulations for invisible cloaks with regular and
irregular shapes verified this method. 相似文献
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The method of designing electromagnetic invisible cloaks
is usually based on the form-invariance of Maxwell's equations in
coordinate transformation. The exterior boundary of a cylindrical
invisible cloak is unchanged and the interior boundary is extended
from that of a point to that of a cylindrical region in coordination
transformation. This transformation process makes perfect cloaks,
but it causes singularity in the constitutive material parameters of
cloaks. This singularity makes the cloaks impossible to realize
in practice. In order to remove this singularity, this paper sets
a small cylindrical region replacing a point in the space
transformation. The cylindrical region is so small that it does not
affect the invisibility effects, but it can remove the singularity for
material parameters. Full wave simulations based on the finite element
method were used to verify the designed cloaks. 相似文献
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