排序方式: 共有4条查询结果,搜索用时 15 毫秒
1
1.
2.
3.
Correlation of Lithium Ionic Diffusion with Nb Concentration in Li7-xLa3Zr2-xNbxO12 Evaluated by an Internal Friction Method 下载免费PDF全文
Solid lithium-ion conductors Li7-xLa3Zr2-xNbxO12(x =0.25, 0.5, 1, 1.5) with cubic garnet structure are suc- cessfully prepared by a solid state reaction method, and the effects of Nb concentration on lithium ion diffusion are investigated by means of internal friction (IF) technique. A prominent relaxation-type IF peak (actually composed of two components) is observed in each Nb doped LiTLa3Zr2012 compound: with apeak PL at lower temperature and a peak PH at higher temperature. The mechanisms of the two components are suggested to be associated with two diffusion processes of lithium ions via vacancies: 48g ←→ 48g and 489 ←→ 24d. The relaxational strength of the IF peak gradually decreases, which is accompanied by the activation energy increasing from 0.45 eV to 0.64 eV with the increasing Nb doping level. The corresponding mechanism is ascribed to originate from lattice contraction as well as the lower concentration of diffusion ions induced by the substitution of Zr4+ by Nb5+. 相似文献
4.
高三的数学复习不能简单看作是知识点的重复,而是学生在教师的引领下,一方面对知识点加深理解并进行梳理与归纳,另一方面更要关注数学知识与数学结构以及数学各分支之间的贯通与联结,使得学生在进一步熟练知识的基础上提升应用知识分析问题、解决问题的能力,最终使得学生的数学能力实现提升.如何实现这一目标呢?笔者在刚过去的2011年高三的数学复习中进行了实践,不断引导学生构建认知单元,使学生的数学能力得到了较大的提升,取得了满意的复习效果. 相似文献
1