基于20kW燃料电池电堆及燃料电池测试系统,获得燃料电池极化曲线及氢气消耗量曲线;基于锂离子动力电池充放电系统,获得锂离子动力电池输出电压曲线.将试验所得数据导入到LMS AMESim软件中,分别构建燃料电池及锂离子动力电池模块,同时,...基于20kW燃料电池电堆及燃料电池测试系统,获得燃料电池极化曲线及氢气消耗量曲线;基于锂离子动力电池充放电系统,获得锂离子动力电池输出电压曲线.将试验所得数据导入到LMS AMESim软件中,分别构建燃料电池及锂离子动力电池模块,同时,构建仿真平台其他所需模块并搭建DC/DC变换器模型,建立燃料电池-锂离子动力电池混合的动力系统仿真平台.依据不同动力源的各自特点,引入能量控制策略,对该混合动力系统进行模拟仿真.在所选定新欧洲驾驶循环(new European driving cycle,NEDC)工况下仿真结果表明,该混合动力系统可以满足车辆在所选定工况下的动力需求.DC/DC变换器可提升并稳定燃料电池输出电压跟随母线电压,并通过对电流的分配进行功率在不同动力源之间的分配;燃料电池输出功率在合理范围之内,并取消燃料电池在低功率下的工况,从而保护燃料电池,延长其使用寿命;锂离子动力电池荷电状态(state of charge,SOC)始终保持在合理范围内,未出现过充或过放情况.研究结果可为搭建混合动力试验平台及整车搭载匹配提供理论依据及参考.展开更多
This paper presents a review of the literature on the effectiveness of Blackboard system, its uses and limitations in information management and highlights the ongoing debate of it. A critical evaluation of Blackboard...This paper presents a review of the literature on the effectiveness of Blackboard system, its uses and limitations in information management and highlights the ongoing debate of it. A critical evaluation of Blackboard system literature reveals a good number of academic views, studies, theories, models and experiences regarding the virtual learning environment. The extant literature shows that the world of information management is always in flux as it is being impacted on by the learning technology such as blackboard system. Blackboard system now has a recognised presence in the information management of the education system. Now the question is: how effective is this Blackboard system? The article will explore, in part, how blackboard is designed as suitable learning models in terms of learner cognitive engagement and constructivist perspective, resulting in the effective Blackboard system. It will further cover to review the effectiveness of Blackboard as an aid to pedagogy. Finally, the article will also present a comparison between Blackboard and other LMS such as Moodle to explore the effectiveness and limitations of the Blackboard for better academic information management.展开更多
Forest development type(FDT) is an expectation pattern for forest management object. Based on investigation data and reference to other stands data in the similar environment,FDT of Pinus caribaea in Baisha County,Hai...Forest development type(FDT) is an expectation pattern for forest management object. Based on investigation data and reference to other stands data in the similar environment,FDT of Pinus caribaea in Baisha County,Hainan Province was designed. Accordidng to the condition of forest stand,it was the object to transform pure coniferous stand to close to nature stand with the structure of coniferous broadleafed mixed forest. On the other hand,visualization of FDT by LMS(landscape management system),was performed for management Pinus caribaea in future.展开更多
开放与远程教育将来自不同国家或地区的学习者联系起来,通过Internet和学习管理系统(Learn-ing Management System,简称LMS)的支持,学习者可以方便地进行网上交互和学习。学习者网上交互是学习者对所学知识的理解和深化的过程,因此交互...开放与远程教育将来自不同国家或地区的学习者联系起来,通过Internet和学习管理系统(Learn-ing Management System,简称LMS)的支持,学习者可以方便地进行网上交互和学习。学习者网上交互是学习者对所学知识的理解和深化的过程,因此交互成为提高学习质量的重要方式。然而,学习者网上交互受到多个因素的影响。本文以上海电视大学(Shanghai TV University,简称SHTVU)和马来西亚宏愿大学(Wawasan Open U-niversity,简称WOU)的学习者为研究对象,并对他们的网上交互进行了比较研究。研究发现了两国学习者网上交互行为的差异,并从国家文化差异、LMS的支持作用和教学模式的设计三个方面分析了差异产生的原因。针对这些原因,我们给出一些建议以帮助提高学习者网上学习的质量。展开更多
文摘基于20kW燃料电池电堆及燃料电池测试系统,获得燃料电池极化曲线及氢气消耗量曲线;基于锂离子动力电池充放电系统,获得锂离子动力电池输出电压曲线.将试验所得数据导入到LMS AMESim软件中,分别构建燃料电池及锂离子动力电池模块,同时,构建仿真平台其他所需模块并搭建DC/DC变换器模型,建立燃料电池-锂离子动力电池混合的动力系统仿真平台.依据不同动力源的各自特点,引入能量控制策略,对该混合动力系统进行模拟仿真.在所选定新欧洲驾驶循环(new European driving cycle,NEDC)工况下仿真结果表明,该混合动力系统可以满足车辆在所选定工况下的动力需求.DC/DC变换器可提升并稳定燃料电池输出电压跟随母线电压,并通过对电流的分配进行功率在不同动力源之间的分配;燃料电池输出功率在合理范围之内,并取消燃料电池在低功率下的工况,从而保护燃料电池,延长其使用寿命;锂离子动力电池荷电状态(state of charge,SOC)始终保持在合理范围内,未出现过充或过放情况.研究结果可为搭建混合动力试验平台及整车搭载匹配提供理论依据及参考.
文摘This paper presents a review of the literature on the effectiveness of Blackboard system, its uses and limitations in information management and highlights the ongoing debate of it. A critical evaluation of Blackboard system literature reveals a good number of academic views, studies, theories, models and experiences regarding the virtual learning environment. The extant literature shows that the world of information management is always in flux as it is being impacted on by the learning technology such as blackboard system. Blackboard system now has a recognised presence in the information management of the education system. Now the question is: how effective is this Blackboard system? The article will explore, in part, how blackboard is designed as suitable learning models in terms of learner cognitive engagement and constructivist perspective, resulting in the effective Blackboard system. It will further cover to review the effectiveness of Blackboard as an aid to pedagogy. Finally, the article will also present a comparison between Blackboard and other LMS such as Moodle to explore the effectiveness and limitations of the Blackboard for better academic information management.
文摘Forest development type(FDT) is an expectation pattern for forest management object. Based on investigation data and reference to other stands data in the similar environment,FDT of Pinus caribaea in Baisha County,Hainan Province was designed. Accordidng to the condition of forest stand,it was the object to transform pure coniferous stand to close to nature stand with the structure of coniferous broadleafed mixed forest. On the other hand,visualization of FDT by LMS(landscape management system),was performed for management Pinus caribaea in future.
文摘开放与远程教育将来自不同国家或地区的学习者联系起来,通过Internet和学习管理系统(Learn-ing Management System,简称LMS)的支持,学习者可以方便地进行网上交互和学习。学习者网上交互是学习者对所学知识的理解和深化的过程,因此交互成为提高学习质量的重要方式。然而,学习者网上交互受到多个因素的影响。本文以上海电视大学(Shanghai TV University,简称SHTVU)和马来西亚宏愿大学(Wawasan Open U-niversity,简称WOU)的学习者为研究对象,并对他们的网上交互进行了比较研究。研究发现了两国学习者网上交互行为的差异,并从国家文化差异、LMS的支持作用和教学模式的设计三个方面分析了差异产生的原因。针对这些原因,我们给出一些建议以帮助提高学习者网上学习的质量。
