检索结果-南通市图书馆

Main issues in research and practice of environmental protection for water conservancy and hydropower projects in China

引用

Water Science and Engineering 2016年第4期9卷 312-323页

作者： ang chen Miao Wu Kai-qi chen Zhi-yu Sun chen Shen Peng-yuan Wang Institute of Hydropower and Environment Research China Three Gorges Corporation School of Civil Engineering Tsinghua University College of Hydrology and Water Resources Hohai University Appraisal Center for Environment and Engineering Ministry of Environmental Protection

In this paper,we generally summarize the main issues in the operational period of water conservancy and hydropower projects in China over the past several ***,the adverse impacts of these projects since the technical guidelines were proposed in 2006 are ***,combined with projects and experience from 2006 to 2014,the four main issues are summarized:(1) There exist many questions in the design and construction of fishways,which are useful for fish migration,and the migration effects are not as expected.(2) Temperature stratification affecting the downstream fish is the major impact of temperature,and alters fish spawning in the reproduction season.(3)Ecological base flow has been one of the primary questions of the last 30 years in China,the greatest related difficulty being quantification of the amount and flow process necessary to satisfy fish life history.(4) Fish habitat protection and restoration are popular topics in recent years with the development of river ecosystem *** habitat loss due to the impacts of dam construction and habitat fragmentation has become more and more *** four issues are now the main difficulties in water project management,and interact with one another to bear combined effects on river *** issues of eco-hydraulic consideration in the design period are the key ***,future priorities for research and practice of environmental protection for water conservancy and hydropower projects in China are *** main purpose of this paper is to enhance the scientific research,monitoring,and assessment of operating effectiveness.

关键词： Temperature stratification Ecological base flow Fish habitat Environmental protection

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

磷块岩成矿过程及其稀土元素富集机理综述

引用

岩石矿物学杂志 2024年第5期43卷 1199-1217页

作者：雷梦丹钟日晨崔浩王赵依陈缓李艳霞于畅邓依凌一凡李默洁黎子萌陈昂快北京科技大学土木与资源工程学院北京100083 中国地质大学(北京)地球科学与资源学院北京100083

磷块岩矿床是以细晶磷灰石为主要矿石矿物的一种海相沉积磷矿床,形成于古元古代后6个历史时期的上升流地区,与生物活动重要节点、大陆风化加剧时期密切相关。磷块岩矿床的形成受海平面升降、微生物活动与沉积物孔隙水中的物理化学条件... 详细信息

磷块岩矿床是以细晶磷灰石为主要矿石矿物的一种海相沉积磷矿床,形成于古元古代后6个历史时期的上升流地区,与生物活动重要节点、大陆风化加剧时期密切相关。磷块岩矿床的形成受海平面升降、微生物活动与沉积物孔隙水中的物理化学条件等因素控制,而形成高品质磷块岩矿床的关键是极低的沉积速率与周期性的海底风暴。部分磷块岩中超常富集中重稀土元素,是潜在的稀土资源来源。磷块岩中稀土元素的主要赋存矿物为细晶磷灰石,其中的稀土元素主要来源于沉积时期的海水和早期成岩时期的沉积物孔隙水,并以吸附或晶格替代的方式储存于细晶磷灰石中。稀土元素可以通过形成稀土-碳酸盐络合物等方式吸附于海洋微粒表面,当氧化还原条件变化时,海洋微粒分解并将稀土元素释放至沉积物孔隙水中。本文通过文献综述发现不同海洋微粒对于稀土元素的吸附具有选择性,从而导致不同的孔隙水具有不同的稀土元素配分模式,进而影响磷块岩矿床中细晶磷灰石的稀土元素配分模式。细晶磷灰石对于稀土元素的富集不具有选择性,故受海水影响较大时呈现重稀土元素富集特征,而受孔隙水影响较大时则呈现中稀土元素凸起特征。由于超常富集稀土元素的磷块岩矿床常呈现中稀土元素凸起的稀土元素配分模式,这与海底热液输入的铁锰氧化物的稀土元素配分特征以及早期成岩过程中孔隙水的稀土元素配分特征相符,这或许指示着海底热液活动输入的铁锰氧化物及早期成岩过程对于磷块岩矿床稀土元素富集过程的影响。本文从磷块岩矿床的特征、时空分布及成矿的控制要素等方面对于磷块岩矿床的成矿过程进行了综述,从磷块岩矿床的稀土元素含量及稀土元素异常分析磷块岩成矿过程中稀土元素的富集行为和分异行为,并讨论了超常富集稀土元素的磷块岩中稀土元素可能存在的富集机理。研究磷块岩成矿过程及其稀土元素富集机理,可以为超常富集稀土元素的磷块岩矿床的勘查开发提供理论依据,对于保障稀土资源供应具有重要意义。

关键词：磷块岩稀土元素深海沉积物早期成岩过程铁锰氧化物

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Bound states in the continuum based on the total internal reflection of Bloch waves

引用

National Science Review 2023年第1期10卷 178-186页

作者： Peng Hu Chongwu Xie Qianju Song ang chen Hong Xiang Dezhuan Han Jian Zi College of Physics Chongqing University State Key Laboratory of Surface Physics Key Laboratory of Microand Nano-Photonic Structures (Ministry of Education) and Department of Physics Fudan University Chongqing Key Laboratory for Strongly Coupled Physics

A photonic-crystal slab can support bound states in the continuum(BICs) that have infinite lifetimes but are embedded into the continuous spectrum of optical modes in free *** formation of BICs re quires a total internal reflection(TIR) condition at both interfaces between the slab and the free ***,we show that the TIR of Bloch waves can be directly obtained based on the generalized Fresnel equations *** each of these Bloch waves picks up a phase with integer multiples of 2π for traveling a round trip,light can be perfectly guided in the slab,namely forming a BIC.A BIC solver with low computational complexity and fast convergence speed is developed,which can also work efficiently at high frequencies beyond the diffraction limit where multiple radiation channels *** examples of multi-channel BICs are shown and their topological nature in momentum space is also *** can be attributed to the coincidence of the topological charges of far-field radiations from different radiation *** concept of the generalized TIR and the TIR-based BIC solver developed offer highly effective approaches for explorations of BICs that could have many potential applications in guided-wave optics and enhanced light-matter interactions.

关键词： bound states in the continuum total internal reflection Bloch waves generalized Fresnel equations topological charges

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Learners’motivational response to the Science,PE,&Me!curriculum:A situational interest perspective

引用

Journal of Sport and Health Science 2021年第2期10卷 243-251页

作者： Senlin chen Haichun Sun Xihe Zhu ang chen Catherine D.Ennis(Posthumous) School of Kinesiology Louisiana State UniversityBaton RougeLA 70803USA Department of Teaching and Learning University of South FloridaTampaFL 33620USA Department of Human Movement Sciences Old Dominion UniversityNorfolkVA 23529USA Department of Kinesiology University of North Carolina at GreensboroGreensboroNC 27402USA

Background:The Science,PE,&Me!(SPEM)curriculum is a concept-based physical education curriculum that offers students coherent educational experiences for constructing health-related fitness knowledge through movement *** purpose of this study was to evaluate students’motivational response to the SPEM curriculum from the situational interest ***:The study used a cluster randomized controlled design in which 30 elementary schools in one of the largest metropolitan areas in the eastern United States were randomly assigned to an experimental or comparison *** all students in the 3rd,4th,and 5th grades in the targeted schools were eligible to participate in the study,a random sample of students from the experimental(n=1749;15 schools)and comparison groups(n=1985;15 schools)provided ***’motivational response to the SPEM curriculum or comparison curriculum was measured using the previously validated Situational Interest *** were analyzed using structural mean ***:The results demonstrated that the experimental group(as reference group)showed significantly higher enjoyment(z=-2.01),challenge(z=-6.54),exploration(z=-12.195),novelty(z=-8.80),and attention demand(z=-7.90)than the comparison ***:The findings indicate that the SPEM curriculum created a more situationally interesting context for learning than the comparison physical education curriculum.

关键词： Constructivist learning theory Curriculum intervention Elementary physical education Learner motivation Structural mean modeling

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

基于深度强化学习的无人机通信网络效率优化

引用

舰船电子工程 2024年第6期44卷 60-64页

作者：伍亮习彤汤巍姜军陈昂西藏大学信息科学技术学院拉萨850000 西华师范大学教育学院南充637002

随着无人机在各种应用中的广泛应用,其通信网络的安全性、频谱和能源效率问题逐渐凸显。该研究针对无人机群通信网络提出了一种基于深度强化学习的联合优化策略。首先构建了一个考虑安全威胁、频谱共享和能源消耗的模型。然后,通过深度... 详细信息

随着无人机在各种应用中的广泛应用,其通信网络的安全性、频谱和能源效率问题逐渐凸显。该研究针对无人机群通信网络提出了一种基于深度强化学习的联合优化策略。首先构建了一个考虑安全威胁、频谱共享和能源消耗的模型。然后,通过深度强化学习训练了智能代理来动态地选择最佳的频谱分配和能源策略,以在保证网络安全的同时提高频谱和能源效率。通过大量的仿真实验,证明了该方法在提高通信安全性、频谱利用率和能源效率方面均表现出色,且相比传统基线和平均分配DQN-wopa~([15])方法有明显的优势。

关键词：无人机安全性频谱能效优化深度强化学习

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Operationalizing physical literacy for learners: Embodying the motivation to move

引用

Journal of Sport and Health Science 2015年第2期4卷 125-131页

作者： ang chen Department of Kinesiology University of North Carolina at Greensboro

Physical literacy is a concept that is expected to encompass the mind and body in an integrated way to explain, promote, and help sustain human beings＇ fundamental function： movement. According to Whitehead（2010）, physical literacy is defined by motivation, especially by competence-based and interest-based motivation. This point of view is consistent with vast amount of research evidence on children and adolescents＇ physical activity behavior. In the article I attempt to interpret and operationalize physical literacy from a perspective that children＇s motivation in physical education is both an innate mental disposition and an acquired/learned attribute. Particularly I rely on the conceptual learning theory and motivation regulation mechanisms of the self-determination theory to argue that in physical education, children should experience tasks that inspire them to embody competence and interest along with self-regulation strategies necessary for developing and sustaining the motivation to move.

关键词： Extrinsic motivation Intrinsic motivation Motivation embodiment Physical literacy

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

基于灰度图二值化的汽车制动器摩擦片残缺检测方法

引用

内燃机与配件 2024年第6期 19-21页

作者：杨秀娥金卢佳徐路平陈昂长兴新城机动车排气检测有限公司湖州313100 绍兴越弘车辆检测有限公司绍兴312000 衢州星光机动车检测有限公司衢州324000 义乌市中益机动车性能检测有限公司金华322000

由于传统方法在汽车制动器摩擦片残缺检测应用中正检率比较低,无法达到预期的检测效果,提出基于灰度图二值化的汽车制动器摩擦片残缺检测方法。采用CCD工业相机采集到摩擦片图像信息,通过对摩擦片灰度图二值化处理,提取到摩擦片图像前... 详细信息

由于传统方法在汽车制动器摩擦片残缺检测应用中正检率比较低,无法达到预期的检测效果,提出基于灰度图二值化的汽车制动器摩擦片残缺检测方法。采用CCD工业相机采集到摩擦片图像信息,通过对摩擦片灰度图二值化处理,提取到摩擦片图像前景区域,利用递增函数计算出摩擦片轮廓连通域,提取到摩擦片残缺特征,从而识别检测出摩擦片残缺。经实验证明,设计方法正检率在95%以上,在汽车制动器摩擦片残缺检测方面具有良好的应用前景。

关键词：灰度图二值化汽车制动器摩擦片残缺检测递增函数

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

市级妇幼保健医院重点学科建设的思路

引用

当代医学 2024年第6期30卷 191-194页

作者：文礼娟陈昂杨颖柔肖琼清孙晓芳中山市博爱医院科教部广东中山528400

市级妇幼保健院属于医疗临床医学及公共卫生服务的结合,是我国医疗卫生事业的重要构成,国家“十四五”卫生健康战略加强出生缺陷、妇幼保健及公共医疗的发展。本院的重点特色专科生殖健康与不孕症专科、产前诊断中心、儿科、产科、妇女... 详细信息

市级妇幼保健院属于医疗临床医学及公共卫生服务的结合,是我国医疗卫生事业的重要构成,国家“十四五”卫生健康战略加强出生缺陷、妇幼保健及公共医疗的发展。本院的重点特色专科生殖健康与不孕症专科、产前诊断中心、儿科、产科、妇女保健和儿童保健科与国家健康战略契合,是医院发展的机遇,而伴随社会经济持续发展及人们对医疗卫生服务要求的不断提升,医院面临的挑战更加严峻。市级妇幼保健院必须通过加强重点学科建设实现可持续发展,通过重点学科建设提升市级妇幼保健院的核心竞争力及医疗卫生服务综合能力水平。本文从重点学科的内涵出发,分析市级妇幼保健院重点学科建设的重要性,市级妇幼保健院重点学科建设的思路及其执行方法,以推动市级妇幼保健院的重点学科建设,提升其医疗卫生服务的整体水平。

关键词：市级妇幼保健机构重点学科建设思路设计

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Phase characterisation of metalenses

引用

Light(Science & Applications) 2021年第4期10卷 551-561页

作者： Maoxiong Zhao Mu Ku chen Ze-Peng Zhuang Yiwen Zhang ang chen Qinmiao chen Wenzhe Liu Jiajun Wang Ze-Ming chen Bo Wang Xiaohan Liu Haiwei Yin Shumin Xiao Lei Shi Jian-Wen Dong Jian Zi Din Ping Tsai State Key Laboratory of Surface Physics Key Laboratory of Micro-and Nano-Photonic Struaures(Ministry of Education)and Department of PhysicsFudan University200433 ShanghaiChina Department of Electronic and Information Engineering The Hong Kong Polytechnic University999077 Hong KongChina School of Physics and State Key Laboratory of Optoelectronic Materials and Technologies Sun Yat-sen University510275 GuangzhouChina Shanghai Engineering Research Center of Optical Metrology for Nanofabrication(SERCOM) 200433 ShanghaiChina State Key Laboratory on Tunable Laser Technology Ministry of Industry and Information Technology Key Lab of Micro-Nano Optoelectronic Information SystemShenzhen Graduate SchoolHarbin Institute of Technology518055 ShenzhenChina

Metalenses have emerged as a new optical element or system in recent years,showing superior performance and abundant ***,the phase distribution of a metalens has not been measured directly up to now,hindering further quantitative evaluation of its *** have developed an interferometric imaging phase measurement system to measure the phase distribution of a metalens by taking only one photo of the interference *** on the measured phase distribution,we analyse the negative chromatic aberration effect of monochromatic metalenses and propose a feature size of *** sensitivities of the phase response to wavelength between the Pancharatnam-Berry phase-based metalens and propagation phase-reliant metalens are directly observed in the ***,through phase distribution analysis,it is found that the distance between the measured metalens and the brightest spot of focusing will deviate from the focal length when the metalens has a low nominal numerical aperture,even though the metalens is ideal without any fabrication *** also use the measured phase distribution to quantitatively characterise the imaging performance of the *** phase measurement system will help not only designers optimise the designs of metalenses but also fabricants distinguish defects to improve the fabrication process,which will pave the way for metalenses in industrial applications.

关键词： character distribution nominal

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

基于SWOT分析的科研项目管理策略应用成效分析

引用

现代医院 2024年第2期24卷 314-316页

作者：文礼娟陈昂汪小妹杨颖柔肖琼清黄美欣中山市博爱医院广东中山528400

运用SWOT分析医院科研管理存在的优势及外部机遇,有助于帮助医院弥补内部劣势及规避外部威胁,形成科学、合理的科研项目管理策略。文章选取Y医院作为研究案例,基于SWOT分析方法对Y医院优势、劣势、机遇及威胁,提出针对性的“SO”“WO”... 详细信息

运用SWOT分析医院科研管理存在的优势及外部机遇,有助于帮助医院弥补内部劣势及规避外部威胁,形成科学、合理的科研项目管理策略。文章选取Y医院作为研究案例,基于SWOT分析方法对Y医院优势、劣势、机遇及威胁,提出针对性的“SO”“WO”“ST”“WT”科研管理战略,将科研管理战略应用于医院科研项目管理后Y医院的科研立项、论文、发明专利及成果转化数量明显增多,对Y医院的科研质量具有明显的促进作用。

关键词： SWOT分析科研项目管理策略应用成效

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：