检索结果-南通市图书馆

Using Natural Radionuclides to Trace Sources of Suspended Particles in the Lower Reaches of the Yellow River

Journal of Ocean University of China 2024年第1期23卷 99-108页

作者： ZHANG Han BURNETT CWilliam ZHANG Xiaojie ZHAO Shibin yang disong NAN Haiming YU Zhigang XU Bochao Frontiers Science Center for Deep Ocean Multispheres and Earth System and Key Laboratory of Marine Chemistry Theory and TechnologyMinistry of EducationOcean University of ChinaQingdao 266100China Laboratory for Marine Ecology and Environmental Science Qingdao National Laboratory for Marine Science and TechnologyQingdao 266071China College of Chemistry and Chemical Engineering Ocean University of ChinaQingdao 266100China Department of Earth Ocean and Atmospheric ScienceFlorida State UniversityTallahasseeFL 32306USA North China Sea Environmental Monitoring Center State Oceanic AdministrationKey Laboratory of Ecological Prewarning and Protection of Bohai SeaMNRQingdao 266033China Shandong Provincial Key Laboratory of Marine Ecological Environment and Disaster Prevention and Mitigation Qingdao 266033China

Natural radionuclides are powerful tools for understanding the sources and fate of suspended particulate matter(SPM).Particulate matter with different particle sizes behaves differently with respect to adsorption and desorption.We analyzed the activi-ties and distribution characteristics of multiple natural radionuclides(238U,226Ra,40K,228Ra,7Be and 210Pbex)on size-fractionated SPM at the Lijin Hydrographic Station(Huanghe or Yellow River)every month over a one-year period.Results showed that medium silt(16–32µm)was the main component.As expected,the activity of each radionuclide decreased with an increase of particle size.We examined the sources of SPM with different particle sizes using activity ratios of 226Ra/238U,228Ra/226Ra,40K/238U and 7Be/210Pbex,and concluded that SPM with different particle sizes originated from different sources.Our results indicate that fine SPM(32µm)was mainly derived from resuspension of riverbed sediment.During high runoff periods,the concentration of SPM increased significantly,and the pro-portion of fine particles originating upstream increased.Naturally occurring radioactive isotopes,especially on size-fractionated par-ticles,are therefore seen as useful tracers to understand the sources and behaviors of riverine particles transported from land to sea.

关键词： the Yellow River suspended particulate matter size-fractions radionuclides sediment sources water elutriator

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

Using radium isotopes to quantify submarine groundwater discharge at different scales in the Huanghe River Estuary,China

引用

海洋学报:英文版 2023年第8期42卷 32-39页

作者： Haowei Xu disong yang Xiaoyi Guo Maosheng Gao Guangquan Chen Diansheng Ji Shengtao Chen Huaming Yu Bochao Xu Frontiers Science Center for Deep Ocean Multispheres and Earth System/Key Laboratory of Marine Chemistry Theory and Technology of Ministry of Education Ocean University of ChinaQingdao 266100China Laboratory for Marine Ecology and Environmental Science Qingdao National Laboratory for Marine Science and TechnologyQingdao 266071China College of Chemistry and Chemical Engineering Ocean University of ChinaQingdao 266100China North China Sea Environmental Monitoring Center of State Oceanic Administration/Key Laboratory of Ecological Prewarning and Protection of Bohai Sea Ministry of Natural ResourcesQingdao 266033China Shandong Provincial Key Laboratory of Marine Ecological Environment and Disaster Prevention and Mitigation Qingdao 266033China Qingdao Institute of Marine Geology Qingdao 266071China Key Laboratory of Marine Sedimentology and Environmental Geology First Institute of OceanographyMinistry of Natural ResourcesQingdao 266061China Laboratory for Marine Geology Qingdao National Laboratory for Marine Science and TechnologyQingdao 266237China Yantai Marine Center Ministry of Natural ResourcesYantai 264003China North China Sea Ecological Center Ministry of Natural ResourcesQingdao 266033China Key Laboratory of Ecological Prewarning and Protection of Bohai Sea Ministry of Natural ResourcesQingdao 266033China College of Oceanic and Atmospheric Sciences Ocean University of ChinaQingdao 266100China Sanya Oceanographic Institution Ocean University of ChinaSanya 572000China

As an important land-ocean interaction process,submarine groundwater discharge(SGD)is composed of multiple dynamical processes at different scales and plays an important role in the study of coastal ocean geochemical budgets.However,most of the existing studies focus on the quantification of the total groundwater discharge,few studies are about the differentiation and quantification of groundwater discharge processes at different scales(i.e.,short-scale SGD and long-scale SGD).As a world-class river,the Huanghe River is highly turbid and heavily regulated by humans.These natural and anthropogenic factors have a significant impact on groundwater discharge processes in the Huanghe River Estuary(HRE).In this study,the distribution patterns of the natural geochemical tracer radium isotopes(^(224)Ra and^(223)Ra)and other hydrological parameters in the HRE were investigated during four cruises.By solving the mass balance of^(224)Ra and^(223)Ra in the HRE,the long-scale SGD flux was quantified as 0.01−0.19 m/d,and the short-scale SGD flux was 0.03−0.04 m/d.The rate of short-scale SGD remained essentially constant among seasons,while the rate of long-scale SGD varied considerably at different periods and showed a synchronous trend with the variation of river discharge.The results of this study are significant for understanding the SGD dynamics in the HRE and the contribution of SGD to the ocean geochemical budgets.

关键词： radium isotopes submarine groundwater discharge Huanghe River Estuary

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

Submarine groundwater discharge and benthic biogeochemical zonation in the Huanghe River Estuary

引用

Acta Oceanologica Sinica 2022年第1期41卷 11-20页

作者： Guangquan Chen Bochao Xu Shibin Zhao disong yang William C.Burnett Shaobo Diao Maosheng Gao Xingyong Xu Lisha Wang Key Laboratory of Coastal Science and Integrated Management First Institute of OceanographyMinistry of Natural ResourcesQingdao 266061China Laboratory for Marine Geology Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China Frontiers Science Center for Deep Ocean Multispheres and Earth System/Key Laboratory of Marine Chemistry Theory and Technology of Ministry of Education Ocean University of ChinaQingdao 266100China Marine Ecology and Environmental Science Laboratory Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China College of Chemistry and Chemical Engineering Ocean University of ChinaQingdao 266100China Department of Earth Ocean and Atmospheric ScienceFlorida State UniversityTallahassee 32306USA Qingdao Institute of Marine Geology China Geological SurveyQingdao 266071China

Submarine groundwater discharge(SGD)has received increasing attention by studies on coastal areas;however,its effects on biogeochemical zonation have not been investigated to date.The Huanghe River Estuary(HRE)is a world class river estuary with high turbidity,and heavy human regulation.This study investigated how SGD is related to the benthic biogeochemistry of the HRE.Based on the distribution of several parameters(e.g.,salinity,temperature,dissolved oxygen(DO)levels,p H,radium isotopes,and nutrients),the HRE was subdivided into six different zones,and the SGD fluxes within each zone were quantified and compared.The highest SGD flux was found in the northwest nearshore zone,where it was more than one order of magnitude higher than in the offshore zone.High SGD resulted in low DO and p H,but high nutrient levels in the benthic boundary layer.The southeast nearshore zone was also characterized by high SGD flux,but benthic waters were more oxic because of the dominating inputs by the Huanghe River.These data suggest that such a zonation would help to understand benthic biogeochemical processes.High SGD may not only contribute to the estuarine nutrient budget,but may also contribute to the formation of hypoxia and acidification.

关键词： SGD zonation benthic biogeochemistry radium isotopes Huanghe River Estuary

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

日本政府对外援助机制的军事化转向

引用

现代国际关系 2024年第6期 81-100,140,141页

作者：杨达熊雪晖吴的凇贵州大学东盟研究院、公共管理学院贵州大学经济学院贵州大学公共管理学院

近年来,日本在安全保障领域显示积极扩张姿态,尤其在政府开发援助(ODA)基础上,建立政府安全保障能力强化支援(OSA)机制,显露在国际社会扩大安全职责范围的意图。OSA依托原有ODA,在对外援助的事项、目的、对象和方式上都呈现出军事化动向... 详细信息

近年来,日本在安全保障领域显示积极扩张姿态,尤其在政府开发援助(ODA)基础上,建立政府安全保障能力强化支援(OSA)机制,显露在国际社会扩大安全职责范围的意图。OSA依托原有ODA,在对外援助的事项、目的、对象和方式上都呈现出军事化动向,比此前ODA更加突出安全考量。透视OSA的框架和运作逻辑可以观察到,其深层动因涉及制度话语权争夺、区域力量对比调整、重振地缘影响力的意图等。可以预计,OSA将对日本及其援助对象乃至全世界产生不同程度的深远复杂影响。

关键词：日本政府安全保障能力强化支援(OSA) 对外援助东南亚日菲关系

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

温度效应对CFST拱桥拱肋预拱度取值影响的探讨

引用

山西建筑 2024年第7期50卷 145-147,153页

作者：周弟松广西路桥工程集团有限公司广西南宁530200

为探讨制作温差对拱肋预拱度取值的影响,以某主跨528 m的中承式钢管混凝土拱桥为依托背景,利用MIDAS/civil建立有限元仿真模型,分析了五个不同制作温差梯度对拱肋成拱线形的影响。计算结果表明:当拱肋制作温差与设计基准温度相差较大时... 详细信息

为探讨制作温差对拱肋预拱度取值的影响,以某主跨528 m的中承式钢管混凝土拱桥为依托背景,利用MIDAS/civil建立有限元仿真模型,分析了五个不同制作温差梯度对拱肋成拱线形的影响。计算结果表明:当拱肋制作温差与设计基准温度相差较大时,原设计预拱度可能存在设置不足的情况,建议拱肋预拱度取值应计入拱肋制作温差对成拱线形的影响。此外,依据9座钢管混凝土拱桥实例,在有限元计算结果的基础之上结合Plane函数和Levenberg-Marquardt优化算法,得到了单位环境变温与空钢管状态下拱顶挠度间的显式函数关系式。

关键词：桥梁工程钢管混凝土拱桥制作温差有限元预拱度线形

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

拱桥斜拉扣挂系统高效拆除技术研究

引用

山西建筑 2024年第5期50卷 160-163页

作者：陈泽彬周弟松广西路桥工程集团有限公司广西南宁530200

针对大跨径拱桥多采用斜拉扣挂施工技术进行拱肋节段拼装,通常扣索数量繁多、各扣索间距较密集,传统采用逐级松索的拆除方法面临施工工作量大、拆索效率低的现状,提出一种从拱脚到l/4和l/4到拱顶交替一次拆除扣索的快速拆索方法。该方... 详细信息

针对大跨径拱桥多采用斜拉扣挂施工技术进行拱肋节段拼装,通常扣索数量繁多、各扣索间距较密集,传统采用逐级松索的拆除方法面临施工工作量大、拆索效率低的现状,提出一种从拱脚到l/4和l/4到拱顶交替一次拆除扣索的快速拆索方法。该方法通过拆索过程中对拱肋控制点位移的影响分析,得到拆除不同位置扣索对结构受力变形的影响规律,提出扣索逐根拆除的施工方案,并从拱圈线形、扣索索力和拱圈应力三个方面对比分析了各拆索顺序的影响规律,以此确定最优的拆索方案。

关键词：拱桥斜拉扣挂扣索拆除线形应力拆索方案

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

Using Rn-222 to Study Human-Regulated River Water-Sediment Input Event in the Estuary

引用

Journal of Ocean University of China 2023年第6期22卷 1464-1472页

作者： XU Yuezhi XIAO Liu GAO Maosheng yang disong ZHAO Shibin XU Haowei WANG Lisha ZHANG Xiaojie College of Chemistry and Chemical Engineering Ocean University of ChinaQingdao 266100China Key Laboratory of Marine Chemistry Theory and Technology Ministry of Education and Frontiers Science Center for Deep Ocean Multispheres and Earth SystemOcean University of ChinaQingdao 266100China SGS-CSTC Standard Technical Service(Qingdao)Co. Ltd.Qingdao 266100China Qingdao Institute of Marine Geology China Geological SurveyQingdao 266071China

The implementation of the water sediment regulation scheme(WSRS)is a typical example of artificially controlling land-source input.During WSRS,the water discharge of the Yellow River will increase significantly,and so will the input of terri-genous materials.In this study,we used a natural geochemical tracer 222Rn to quantify terrestrial inputs under the influence of the 2014 WSRS in the Yellow River Estuary.The results indicated that during WSRS the concentration of 222Rn in the estuary increased by about four times than in the period before WSRS.The high-level 222Rn plume disappeared quickly after WSRS,indicating that 222Rn has a very short‘memory effect’in the estuary.Based on the investigation conducted from 2015 to 2016,the concentration of 222Rn tended to be stable in the lower reaches of the Yellow River.During WSRS,the concentrations of 222Rn in the river water in-creased sharply at about 3–5 times greater than in the non-WSRS period.Based on the 222Rn mass balance model,the fluxes of 222Rn caused by submarine groundwater discharge(SGD)were estimated to be(3.5±1.7)×10^(3),(11±3.9)×10^(3),and(5.2±1.9)×10^(3)dpm m^(-2)d^(-1)in the periods before,during,and after WSRS,respectively.This finding indicated that SGD was the major source of 222Rn in the Yellow River Estuary,which can be significantly increased during WSRS.Furthermore,the SGD-associated nutrient fluxes were estimated to be 9.8×10^(3),2.5×102,and 1.1×10^(4)μmolm^(-2)d^(-1)for dissolved inorganic nitrogen,phosphorus,and silicon,respectively,during WSRS or about 2–40 times greater than during the non-WSRS period.

关键词： 222Rn submarine groundwater discharge water sediment regulation scheme nutrient Yellow River

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

Data-driven Estimation of Cloud Effects on Surface Irradiance at Xianghe,a Suburban Site on the North China Plain

引用

Advances in Atmospheric Sciences 2022年第12期39卷 2213-2223页

作者： Mengqi LIU Jinqiang ZHANG Hongrong SHI disong FU Xiang'ao XIA Key Laboratory of Atmospheric Sounding Chengdu University of Information TechnologyChengdu 610225China Key Laboratory of Middle Atmosphere and Global Environment Observation Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science&TechnologyNanjing 210044China

Clouds are a dominant modulator of the energy budget.The cloud shortwave radiative effect at the surface(CRE)is closely related to the cloud macro-and micro-physical properties.Systematic observation of surface irradiance and cloud properties are needed to narrow uncertainties in CRE.In this study,1-min irradiance and Total Sky Imager measurements from 2005 to 2009 at Xianghe in North China Plain are used to estimate cloud types,evaluate cloud fraction(CF),and quantify the sensitivities of surface irradiance with respect to changes in CF whether clouds obscure the sun or not.The annual mean CF is 0.50,further noting that CF exhibits a distinct seasonal variation,with a minimum in winter(0.37)and maximum in summer(0.68).Cumulus occurs more frequently in summer(32%),which is close to the sum of the occurrence of stratus and cirrus.The annual CRE is–54.4 W m^(–2),with seasonal values ranging from^(–2)9.5 W m^(–2)in winter and–78.2 W m^(–2)in summer.When clouds do not obscure the sun,CF is a dominant factor affecting diffuse irradiance,which in turn affects global irradiance.There is a positive linear relationship between CF and CRE under sun-unobscured conditions,the mean sensitivity of CRE for each CF 0.1 increase is about 1.2 W m^(–2)[79.5°

关键词： cloud radiative effect solar radiation cloud fraction cloud-radiation interaction

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

超声心动图联合CT下肺动脉造影评价肺动脉高压患者心功能不全的诊断效能

引用

心电与循环 2024年第1期43卷 48-51,55页

作者：陈迪松华群冯仁海陈炯宁波市第六医院影像科 315100

目的探讨超声心动图联合CT下肺动脉造影(CTPA)评价肺动脉高压(PAH)患者心功能不全的诊断效能。方法选择2018年6月至2020年8月宁波市第六医院收治的PAH患者142例。根据是否发生心功能不全将PAH患者分为观察组37例和对照组105例。比较两... 详细信息

目的探讨超声心动图联合CT下肺动脉造影(CTPA)评价肺动脉高压(PAH)患者心功能不全的诊断效能。方法选择2018年6月至2020年8月宁波市第六医院收治的PAH患者142例。根据是否发生心功能不全将PAH患者分为观察组37例和对照组105例。比较两组超声心动图和CTPA检查有关参数水平。绘制ROC曲线,分析超声心动图联合CTPA评价PAH患者心功能不全的诊断效能。结果观察组右心室收缩压(RVSP)水平高于对照组,右心室射血分数(RVEF)、三尖瓣环收缩期位移(TAPSE)水平低于对照组,差异均有统计学意义(均P3项指标单独预测的AUC。肺动脉直径、右心室横径两者联合预测心功能不全的AUC大于肺动脉直径、右心室横径单独的AUC。超声心动图联合CTPA预测心功能不全的AUC为0.913,大于超声心电图和CTPA单独预测。结论超声心动图联合CTPA有利于预测PAH患者的心功能不全。

关键词：超声心动图 CT下肺动脉造影肺动脉高压心功能不全

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

钢管筒节段高精度加工制造技术研究

引用

山西建筑 2024年第15期50卷 93-96页

作者：郑健马文辉马瑞艺周弟松广西路桥工程集团有限公司广西南宁530200

针对传统钢管筒节加工制作校圆工作量大,且易形成桃心型圆的难题,提出了钢板在卷板前将筒节钢板纵缝两侧预压制成圆弧状,并通过特制弧形样板校圆等一系列措施,形成成套钢管筒节段高精度加工制造工艺。最后,以乐望红水河特大桥主跨528 m... 详细信息

针对传统钢管筒节加工制作校圆工作量大,且易形成桃心型圆的难题,提出了钢板在卷板前将筒节钢板纵缝两侧预压制成圆弧状,并通过特制弧形样板校圆等一系列措施,形成成套钢管筒节段高精度加工制造工艺。最后,以乐望红水河特大桥主跨528 m钢管混凝土拱桥的拱肋筒节段加工制作为工程依托,将该技术应用于工程实践,实践结果表明:该技术能显著提高拱肋的加工精度和校圆效率。

关键词：钢管拱筒节段乐望红水河桥加工制作

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：