期刊文献+
共找到3篇文章
< 1 >
每页显示 20 50 100
Theoretical Perspectives in Strategy Assessment
1
作者 Li Shaojun is a Research Professor at the Institute for World Economic and Political Studies, China Academy of Social Sciences. 《Contemporary International Relations》 2003年第9期2-8,共7页
To assess strategy, it is necessary to define the concept of strategy first. There exist many debates on how to define strategy at present. Usually scholars would like to address the following common propositions: fir... To assess strategy, it is necessary to define the concept of strategy first. There exist many debates on how to define strategy at present. Usually scholars would like to address the following common propositions: first, strategy is the guideline that influences the overall situation; second, strategy is the means and approach to realize goals; third, the implementation of strategy must take strength and 展开更多
关键词 in AS AS theoretical perspectives in Strategy Assessment that for of
下载PDF
打破LiNiO_(2)的能量密度极限:Li_(2)NiO_(3)还是Li_(2)NiO_(2)? 被引量:1
2
作者 贾怡宁 叶耀坤 +6 位作者 刘佳华 郑世胜 林伟成 王竹 李舜宁 潘锋 郑家新 《Science China Materials》 SCIE EI CAS CSCD 2022年第4期913-919,共7页
开发新一代层状氧化物阴极,是发展高能量密度电动汽车锂离子电池迫切关注的问题.目前有一种方法是不断提高镍基层状氧化物中的镍含量,但这一方法的极限是LiNiO_(2).为了突破这一极限,获得更高的能量密度,近年来备受关注的一种方法是在... 开发新一代层状氧化物阴极,是发展高能量密度电动汽车锂离子电池迫切关注的问题.目前有一种方法是不断提高镍基层状氧化物中的镍含量,但这一方法的极限是LiNiO_(2).为了突破这一极限,获得更高的能量密度,近年来备受关注的一种方法是在过渡金属层中引入过量的锂离子,形成Li_(2)MO_(3)(M是过渡金属阳离子).然而,还有一种一直被忽视的方法是在过渡金属层和原始Li层之间插入一层额外的Li离子,形成Li_(2)MO_(2).本研究中,我们选择了典型的Li_(2)NiO_(3)和1T-Li_(2)NiO_(2)作为代表,从理论角度综合比较了Li_(2)NiO_(3)、1T-Li_(2)NiO_(2)和LiNiO_(2)的各项电化学性能.我们发现,不同于LiNiO_(2)中发生的Ni^(3+)/Ni^(4+)单电子阳离子氧化还原,在Li_(2)NiO_(3)中存在着伴有极化子的阴离子氧化还原.而在Li_(2)NiO_(2)中,则发生了伴有绝缘体到金属转变的Ni^(2+)/Ni^(4+)双电子氧化还原.在这三种材料中,由于Li_(2)NiO_(2)具有双电子氧化还原活性,其在容量、能量密度、电导率和热稳定性等方面都表现优异,是最有希望突破LiNiO_(2)极限的下一代层状氧化物阴极材料.虽然Li_(2)NiO_(2)具有脱锂过程中的体积变化较大的缺点,但我们提出了两种可能的解决方法:在Li层中掺杂Na和在TM层中掺杂Mo,都获得了不错的效果.这一工作为如何突破Li-NiO_(2)的能量密度极限,开发下一代具有高能量密度的层状氧化物阴极提供了新的思路. 展开更多
关键词 Li-ion battery Li_(2)NiO_(3)and Li_(2)NiO_(2) double-electron redox anionic redox theoretical perspective
原文传递
Learner Identity in Chinese as a Foreign/Second Language Education:A Critical Review
3
作者 LI Citing LI Wendong 《Frontiers of Education in China》 2020年第1期73-98,共26页
This paper reports the results of a review of 33 journal articles chosen from 87 empirical studies on learner identity in Chinese as a foreign/second language(CFL/CSL)education,published during the years 2005-2019.By ... This paper reports the results of a review of 33 journal articles chosen from 87 empirical studies on learner identity in Chinese as a foreign/second language(CFL/CSL)education,published during the years 2005-2019.By analyzing the co-occurrence of keywords in these Social Science Citation Index(SSCI)journal articles,this review identifies the theoretical perspectives and topical trends of CFL/CSL education research on learner identity.The review shows that while such post-structuralist theories and notions as capital,identity and investment model have continued to play a predominant role in CFL/CSL identity research,interdisciplinary perspectives seem to also demonstrate their theoretical value and interpretive power.Furthermore,the review found that researchers explored a wide array of topical issues in relation to learner identity involved in the complex linguistic and social ecology of Chinese language learning.The review concludes with suggestions for future projects to consider that expand the thematic and theoretical scope by exploring intersections between different social categories and learner identities in societal contexts. 展开更多
关键词 IDENTITY Chinese as a foreign/second language(CFL/CSL) theoretical perspectives topical concerns post-structuralist theories interdisciplinary perspectives
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部