Safety systems, built on state-of-the-art technology, are essential for achieving acceptable levels of plant safety to minimize hazards to the reactor and the general public. The second shutdown system(SSS) as an engi...Safety systems, built on state-of-the-art technology, are essential for achieving acceptable levels of plant safety to minimize hazards to the reactor and the general public. The second shutdown system(SSS) as an engineered safety feature and a part of the reactor protection system(RPS) is a means for rapidly shutting down a nuclear reactor, keeping it in a subcritical state and serving as a backup to the first shutdown system(FSS). In this research, one SSS with two types of optimum chamber designs is proposed that take into account the main current characteristic features of the Tehran research reactor with improvements over earlier designs. They are based on a liquid neutron absorber injection that is preferably different, diverse, and independent from the FSS based on the rod drop mechanism. The major design characteristics of this SSS with two different chambers were investigated using MCNPX 2.6.0 code. The performed calculations showed that the designed SSS is a reliable shutdown system, assuring an appropriate shutdown margin and injection time, with no significant effects on the effective delayed neutron fraction while causing minimal variations to the core structure. Further, the reasonable financial cost and the prolongation of the operation cycle are additional advantages of this design.展开更多
As one of the major factors affecting second language learners' success to their acquisition achievement,motivation has been examined in a wide variety of research papers.It is thus instructive to conduct a critic...As one of the major factors affecting second language learners' success to their acquisition achievement,motivation has been examined in a wide variety of research papers.It is thus instructive to conduct a critical review of both theoretical and empirical developments in SLA research from over the last few decades.This approach will provide a broad,and integrated perspective onto the current understanding of the complextopic of motivation.Such an undertaking is valuable for teachers,and researchers alike,in developing useful teaching methods,and finding futureavenues of SLA motivation research respectively.The following paper provides an overview of recent theoretical and empirical findings,examines some of the problems and contradictions found in current SLA research,and gives an initial departure point for future directions of research in the area of motivation.The paper concludes with a discussion of some of the implications for teachers,and possible classroom strategies that are drawn from the current body of motivation research.展开更多
Based on the theoretical origin of sociocultural views,this paper reviews second language writing from the sociocultural perspective in recent years and puts forw ard suggestions for the follow-up study. Research from...Based on the theoretical origin of sociocultural views,this paper reviews second language writing from the sociocultural perspective in recent years and puts forw ard suggestions for the follow-up study. Research from the sociocultural perspective adopts the overall qualitative research methods,with the sociocultural theories and dialogue theories being the framework,attaching importance to the writing process and social context,and concludes that the theoretical basis,research emphasis and methodology still needs perfection.展开更多
Chomsky’s Universal Grammar(UG)theory not only answers"the logical problem of language acquisition",but also provides insights and thoughts for second language acquisition(SLA)research on both theoretical a...Chomsky’s Universal Grammar(UG)theory not only answers"the logical problem of language acquisition",but also provides insights and thoughts for second language acquisition(SLA)research on both theoretical and empirical level.However,there are many problems of UG-based research.On the theoretical aspect,UG-based approach left untouched many areas apart from"core grammar"and the continual development of the theory is problematic to second language researchers.On the empirical aspects,most experiments reveal problems with the design and data collection process.In short,the evaluation of UG concerning SLA should be developmental and comprehensive.展开更多
Keywords word frequency and co-word analysis are adopted in an attempt to to investigate the focuses and fronts of inter-national second language acquisition(SLA) researches by analyzing the key words in articles publ...Keywords word frequency and co-word analysis are adopted in an attempt to to investigate the focuses and fronts of inter-national second language acquisition(SLA) researches by analyzing the key words in articles published in the internationally re-nowned SLA academic journal Language Learning from 2012 to 2016. It is found that the best researched topics in SLA are vocabu-lary acquisition, explicit knowledge, form-focused teaching, language use, and so on, among which learner's language attracts themost attention. In terms of research methods, they become more diversified and interdisciplinary, as empirical studies take a domi-nant position and experiments still play a leading role, displaying an interdisciplinary feature.展开更多
目的分析国内外护理领域第二受害者的研究现状、研究热点及发展趋势。方法检索Web of Science核心合集数据库和中国知网,对建库至2023年11月20日发表的护理领域第二受害者的相关文献采用CiteSpace 6.2.R4软件进行计量学分析。结果共纳...目的分析国内外护理领域第二受害者的研究现状、研究热点及发展趋势。方法检索Web of Science核心合集数据库和中国知网,对建库至2023年11月20日发表的护理领域第二受害者的相关文献采用CiteSpace 6.2.R4软件进行计量学分析。结果共纳入英文文献169篇、中文文献74篇。国外对于护理领域第二受害者的研究已形成多个核心团队,但国内尚未形成合力。国外对第二受害者的影响因素、支持需求以及干预模式等的研究已经比较成熟,而国内大多停留在对第二受害者经历及支持现状探索的量性研究,质性研究以调查护士在经历不良事件后的心理、情绪体验为主,探索护士的支持需求以及支持获取途径的研究不多。较少有基于政策的支持系统构建和以医院为单位的干预项目。结论国内跨地区、跨机构、跨团队合作有待加强,国内外的热点研究方向具有相似性,均呈现多样化。各级各类医疗机构应进一步研究中国第二受害者的需要,推动建立非惩罚性的医院患者安全文化,未来研究可以逐步探索适合中国医疗情况的第二受害者支持系统。展开更多
文摘Safety systems, built on state-of-the-art technology, are essential for achieving acceptable levels of plant safety to minimize hazards to the reactor and the general public. The second shutdown system(SSS) as an engineered safety feature and a part of the reactor protection system(RPS) is a means for rapidly shutting down a nuclear reactor, keeping it in a subcritical state and serving as a backup to the first shutdown system(FSS). In this research, one SSS with two types of optimum chamber designs is proposed that take into account the main current characteristic features of the Tehran research reactor with improvements over earlier designs. They are based on a liquid neutron absorber injection that is preferably different, diverse, and independent from the FSS based on the rod drop mechanism. The major design characteristics of this SSS with two different chambers were investigated using MCNPX 2.6.0 code. The performed calculations showed that the designed SSS is a reliable shutdown system, assuring an appropriate shutdown margin and injection time, with no significant effects on the effective delayed neutron fraction while causing minimal variations to the core structure. Further, the reasonable financial cost and the prolongation of the operation cycle are additional advantages of this design.
文摘As one of the major factors affecting second language learners' success to their acquisition achievement,motivation has been examined in a wide variety of research papers.It is thus instructive to conduct a critical review of both theoretical and empirical developments in SLA research from over the last few decades.This approach will provide a broad,and integrated perspective onto the current understanding of the complextopic of motivation.Such an undertaking is valuable for teachers,and researchers alike,in developing useful teaching methods,and finding futureavenues of SLA motivation research respectively.The following paper provides an overview of recent theoretical and empirical findings,examines some of the problems and contradictions found in current SLA research,and gives an initial departure point for future directions of research in the area of motivation.The paper concludes with a discussion of some of the implications for teachers,and possible classroom strategies that are drawn from the current body of motivation research.
文摘Based on the theoretical origin of sociocultural views,this paper reviews second language writing from the sociocultural perspective in recent years and puts forw ard suggestions for the follow-up study. Research from the sociocultural perspective adopts the overall qualitative research methods,with the sociocultural theories and dialogue theories being the framework,attaching importance to the writing process and social context,and concludes that the theoretical basis,research emphasis and methodology still needs perfection.
文摘Chomsky’s Universal Grammar(UG)theory not only answers"the logical problem of language acquisition",but also provides insights and thoughts for second language acquisition(SLA)research on both theoretical and empirical level.However,there are many problems of UG-based research.On the theoretical aspect,UG-based approach left untouched many areas apart from"core grammar"and the continual development of the theory is problematic to second language researchers.On the empirical aspects,most experiments reveal problems with the design and data collection process.In short,the evaluation of UG concerning SLA should be developmental and comprehensive.
文摘Keywords word frequency and co-word analysis are adopted in an attempt to to investigate the focuses and fronts of inter-national second language acquisition(SLA) researches by analyzing the key words in articles published in the internationally re-nowned SLA academic journal Language Learning from 2012 to 2016. It is found that the best researched topics in SLA are vocabu-lary acquisition, explicit knowledge, form-focused teaching, language use, and so on, among which learner's language attracts themost attention. In terms of research methods, they become more diversified and interdisciplinary, as empirical studies take a domi-nant position and experiments still play a leading role, displaying an interdisciplinary feature.
文摘目的分析国内外护理领域第二受害者的研究现状、研究热点及发展趋势。方法检索Web of Science核心合集数据库和中国知网,对建库至2023年11月20日发表的护理领域第二受害者的相关文献采用CiteSpace 6.2.R4软件进行计量学分析。结果共纳入英文文献169篇、中文文献74篇。国外对于护理领域第二受害者的研究已形成多个核心团队,但国内尚未形成合力。国外对第二受害者的影响因素、支持需求以及干预模式等的研究已经比较成熟,而国内大多停留在对第二受害者经历及支持现状探索的量性研究,质性研究以调查护士在经历不良事件后的心理、情绪体验为主,探索护士的支持需求以及支持获取途径的研究不多。较少有基于政策的支持系统构建和以医院为单位的干预项目。结论国内跨地区、跨机构、跨团队合作有待加强,国内外的热点研究方向具有相似性,均呈现多样化。各级各类医疗机构应进一步研究中国第二受害者的需要,推动建立非惩罚性的医院患者安全文化,未来研究可以逐步探索适合中国医疗情况的第二受害者支持系统。
