Using Stroh＇s formalism the simple explicit expressions of Green＇s functions for a 2D piezoelectric body with two semi-infinite fixed conductor cracks subjected to a generalized line force were given. The Coulomb fo...Using Stroh＇s formalism the simple explicit expressions of Green＇s functions for a 2D piezoelectric body with two semi-infinite fixed conductor cracks subjected to a generalized line force were given. The Coulomb force acting on the free line charge aroused by the piezoelectricity and the distributed boundary polarization charges was discussed at first. Interactions between two singularities with free charge （s） located in a region with external cracks were studied, too. The numerical results show that the Coulomb force for two or more singularities with one free charge at least will have much influence on the electromechanical fields in piezoelectric media when these singularities move closely with each other and therefore cannot be overlooked again. The solutions obtained are valid not only for plane and anti-plane problems but also for coupled problems between in-plane and out-of-plane deformations.展开更多
From the perspective of individual learner differences,this paper aims to show the readers an outline of the influence of individual learner differences on written corrective feedback.Based on 200 eighth and ninth gra...From the perspective of individual learner differences,this paper aims to show the readers an outline of the influence of individual learner differences on written corrective feedback.Based on 200 eighth and ninth grade junior high school students’thinking patterns and tests,60 students were selected as subjects in this study.Based on the comparative analysis and error analysis in second language acquisition as the main theoretical basis,this study analyzed the common types of errors in the use of nonpredicate verbs in junior high school students and their causes.There are three main questions in this study:how about the error frequency of the five forms(present participle,past participle,infinitive,gerund and independent nominative structure)in the nonpredicate verb learning of junior high school students?What kind of mistakes do junior high school students make in the process of learning non-predicate verbs?According to the conclusion of the investigation and research,the author puts forward some suggestions from the aspects of teachers and students in the last part of the article.展开更多
In this paper,first the author provides a brief review of contemporary psychological views on motivation and motivation in SLL.The author then discusses Williams and Burden' s (1997) cognitive model of motivation,...In this paper,first the author provides a brief review of contemporary psychological views on motivation and motivation in SLL.The author then discusses Williams and Burden' s (1997) cognitive model of motivation,which suggests that both internal and external factors are significant in motivation.And next the author selects two internal factors (attitudes to language learning in general and attitudes to target language community and culture) and two external factors (parents and teachers),discussing their relevance to motivation in language learning.After that the author refers in her answer both to the wider literature on motivation and her own experience of motivation as a language teacher and learner.The author concludes the paper by drawing some practical implications from employing this model.展开更多
文摘Using Stroh＇s formalism the simple explicit expressions of Green＇s functions for a 2D piezoelectric body with two semi-infinite fixed conductor cracks subjected to a generalized line force were given. The Coulomb force acting on the free line charge aroused by the piezoelectricity and the distributed boundary polarization charges was discussed at first. Interactions between two singularities with free charge （s） located in a region with external cracks were studied, too. The numerical results show that the Coulomb force for two or more singularities with one free charge at least will have much influence on the electromechanical fields in piezoelectric media when these singularities move closely with each other and therefore cannot be overlooked again. The solutions obtained are valid not only for plane and anti-plane problems but also for coupled problems between in-plane and out-of-plane deformations.
文摘From the perspective of individual learner differences,this paper aims to show the readers an outline of the influence of individual learner differences on written corrective feedback.Based on 200 eighth and ninth grade junior high school students’thinking patterns and tests,60 students were selected as subjects in this study.Based on the comparative analysis and error analysis in second language acquisition as the main theoretical basis,this study analyzed the common types of errors in the use of nonpredicate verbs in junior high school students and their causes.There are three main questions in this study:how about the error frequency of the five forms(present participle,past participle,infinitive,gerund and independent nominative structure)in the nonpredicate verb learning of junior high school students?What kind of mistakes do junior high school students make in the process of learning non-predicate verbs?According to the conclusion of the investigation and research,the author puts forward some suggestions from the aspects of teachers and students in the last part of the article.
文摘In this paper,first the author provides a brief review of contemporary psychological views on motivation and motivation in SLL.The author then discusses Williams and Burden' s (1997) cognitive model of motivation,which suggests that both internal and external factors are significant in motivation.And next the author selects two internal factors (attitudes to language learning in general and attitudes to target language community and culture) and two external factors (parents and teachers),discussing their relevance to motivation in language learning.After that the author refers in her answer both to the wider literature on motivation and her own experience of motivation as a language teacher and learner.The author concludes the paper by drawing some practical implications from employing this model.
