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Numerical simulation of the impacts of water level variation on water age in Dahuofang Reservoir

Frontiers of Earth Science 2015年第2期9卷 209-224页

作者： xinwen li yongming shen State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116023 China

The transport timescales were investigated in response to water level variation under different constant flow rates in Dahuofang Reservoir. The concept of water age was applied to quantifY the transport timescales. A three-dimensional hydrodynamic model was developed based on the Environmental Fluid Dynamics Code （EFDC）. The model was calibrated for water surface elevation and temperature profiles from April 1, 2008 to October 31, 2008. Comparisons of observed and modeled data showed that the model reproduced the water level fluctuation and thermal stratification during warm season and vertical mixing during cold season fairly well. The calibrated model was then applied to investigate the response of water age to water level changes in Dahuofang Reservoir. Model results showed that water age increases from confluence toward dam zone. In the vertical direction, the water age is relatively uniform at upstream and stratifies further downstream, with a larger value at bottom layer than at surface layer. Comparisons demonstrated that water level variation has a significant impact on transport timescales in the reservoir. The impact of water level drawdown on water age is stronger at bottom layer than at surface layer. Under high flow conditions, the water age decreases 0-20days at surface layer and 15-25 days at bottom layer. Under mean flow conditions, the water age decreases 20-30 days at surface layer and 30-50 days at bottom layer. Furthermore, the impact is minor in the upstream and increases further downstream. The vertical stratification of water age weakens as the water level decreases. This study provides a numerical tool to quantify the transport timescale in Dahuofang Reservoir and supports adaptive management of regional water resources by local authorities.

关键词： water age EFDC Dahuofang Reservoir,numerical simulation water level

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Computational investigation on hydrodynamic and sediment transport responses influenced by reclamation projects in the Meizhou Bay,China

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Frontiers of Earth Science 2020年第3期14卷 493-511页

作者： Gefei Deng yongming shen Changping li Jun Tang Institute of Environmental and Ecological Engineering Guangdong University of TechnologyGuangzhou510006China State Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian116024China Research Center for Eco-Environmental Engineering Dongguan University of TechnologyDongguan523808China

Reclamation projects are the main method of coastal exploitation,and the hydrodynamic environmental effect,together with the sediment transport response of the reclamation project,is important to the project’s site selection and environmental ***,a 3D numerical model based on the finite volume community ocean model(FVCOM)is applied to simulate the changes in the Meizhou Bay’s hydrodynamic environment and sediment transport after a reclamation *** reclamation project greatly alters the shape of the shoreline and narrows the bay,leading to a significant change in its hydrodynamic environment and sediment *** the project,the clockwise coastal residual current in the corner above the Meizhou Island gradually *** obvious counter-clockwise coastal residual current emerges around the rectangular *** tidal prism decreases by 0.65×10^9 and 0.44×10^9 m^3 in the spring and neap tides,*** residence time presents a major *** changes lead to the weakening of the water exchange capacity and the reduction of the self-purification capacity of the *** in the tidal channel weaken,whilst currents in the horizontal channel *** strength and scope of particle trajectories around the horizontal channel and the Meizhou Island *** suspended sediment concentration(SSC)increases in the majority of the Meizhou Bay but decreases in the lateral *** eastern corner of Z2 shows a tendency to *** western region of the Meizhou Island,the upper portion of the rectangular corner and the western corner of Z4 show a tendency to *** reclamation project increases the maximum storm surges by 0.06 m and decreases the maximum significant wave heights by 0.09 m.

关键词： Meizhou Bay FVCOM-h SWAN reclamation project hydrodynamic environment SSC typhoon

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Rapid decrease in Antarctic sea ice in recent years

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Acta Oceanologica Sinica 2021年第7期40卷 119-128页

作者： Guanghua Hao Hui shen yongming Sun Chunhua li Key Laboratory of Marine Hazards Forecasting National Marine Environmental Forecasting CenterMinistry of Natural ResourcesBeijing 100081China Key Laboratory of Physical Oceanography College of Oceanic and Atmospheric SciencesOcean University of ChinaQingdao 266100China Pilot National Laboratory for Marine Science and Technology(Qingdao) Qingdao 266237China

A 41-year Antarctic sea ice concentration(SIC)dataset derived from satellite passive microwave radiometers during the period of 1979–2019 has been used to analyze sea ice changes in recent *** trends of SIC and sea ice extent(SIE)are calculated during the periods of 1979–2019,1979–2013,and 2014–*** trends show regionally dependent *** SIC shows an increasing trend in most of the regions except the Bellingshausen Sea and Amundsen Sea(BA)during 1979–2019 and 1979–*** SIE trend shows a decreasing or decelerating trend in the period of 1979–2019((6835±2210)km^(2)/a)compared with the 1979–2013 period((18600±2203)km^(2)/a).In recent years(2014–2019),the SIC and SIE have exhibited decreasing trends(–(34567±3521)km^(2)/month),especially in the Weddell Sea(WS)and Ross Sea(RS)during summer and *** trends are related to regionally dependent *** analyses show that the SIC and SIE decreased in response to the warming trend of 2 m air temperature(T_(a-2m))and have exhibited a good relationship with T_(a-2m) in summer and autumn in recent *** sea ice decrease in the Antarctic is mainly caused by increases in absorbed energy and southward energy transportation in recent years,such as the increase in gained solar radiation and moist static energy from the south,which demonstrate notable regional *** the WS region,the local positive feedback from the additional absorbed solar radiation,resulting in warmer air and reduced sea ice,is the main reason for the sea ice decrease in recent *** increase in southward energy transport has also favored a decrease in sea *** the RS region,the increase in southward-transported moist static energy has contributed to the decrease in sea ice,and the increases in cloud cover and longwave radiation have prevented sea ice growth.

关键词： sea ice Antarctic decreasing atmosphere

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Integrated supersonic wind tunnel nozzle

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Chinese Journal of Aeronautics 2019年第11期32卷 2422-2432页

作者： Junmou shen Jingang DONG Ruiqu li Jiang ZHANG Xing CHEN yongming QIN Handong MA China Academy of Aerospace Aerodynamics Beijing 100074China School of Mechanical Aerospace and Civil EngineeringThe University of ManchesterManchester Ml 7DNUK

In supersonic wind tunnels, the airflow at the exit of a convergent-divergent nozzle is affected by the connection between the nozzle and test section, because the connection is a source of disturbance for supersonic flow and the source of disturbance generated by this disturbance propagates downstream. In order to avoid the disturbance, the test can only be carried out in the rhombus area. However, for the supersonic nozzle, the rhombus region is small, limiting the size and attitude angle of the test model. An integrated supersonic nozzle is a nozzle and a test section as a whole, which is designed to weaken or eliminate the disturbance. The inviscid contour of the supersonic nozzle is based on the method of characteristics. A new curve is formed by the smooth connection between the inviscid contour and test section, and the boundary layer is corrected for the overall curve. Integrated supersonic nozzles with Mach number 1.5 and 2 are designed, which are based on this method. The flow field is validated by numerical and experimental results. The results of the study highlight the importance of the connection about the nozzle outlet and test section. They clearly show that the wave system does not exist at the exit of the supersonic nozzle, and the flow field is uniform throughout the test section.

关键词： Boundary layer Disturbance Flow field Integrated supersonic nozzle Supersonic wind tunnels The rhombus region

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Dissipation of polycyclic aromatic hydrocarbons and microbial activity in a field soil planted with perennial ryegrass

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Frontiers of Environmental Science & Engineering 2012年第3期6卷 330-335页

作者： Dengqiang FU Ying TENG Yuanyuan shen Mingming SUN Chen TU yongming LUO Zhengao li Peter CHRISTIE Key Laboratory of Soil Environment and Pollution Remediation Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China Agri-Environment Branch Agri-Food and Biosciences InstituteNewforge LaneBelfast BT95PXUK

Dissipation and plant uptake of polycyclic aromatic hydrocarbons （PAHs） in contaminated agricul- tural soil planted with perennial ryegrass were investigated in a field experiment. After two seasons of grass cultivation the mean concentration of 12 PAHs in soil decreased by 23.4% compared with the initial soil. The 3-, 4-, 5-, and 6- ring PAHs were dissipated by 30.9%, 25.5%, 21.2%, and 16.3% from the soil, respectively. Ryegrass shoots accumulated about 280 ***1, shoot dry matter biomass reached 2.48 x 104kg-ha1, and plant uptake accounted for about 0.99% of the decrease in PAHs in the soil. Significantly higher soil enzyme activities and microbial community functional diversity were observed in planted soil than that in the unplanted control. The results suggest that planting ryegrass may promote the dissipation of PAHs in long-term contaminated agricultural soil, and plant-promoted microbial degradation may be a main mechanism of phytoremediation.

关键词： perennial ryegrass polycyclic aromatic hydrocarbon bioremediation plant uptake soil microbial activity

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Einstein Probe discovery of EP240408a: A peculiar X-ray transient with an intermediate timescale

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Science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 222-240页

作者： Wenda Zhang Weimin Yuan Zhixing ling Yong Chen Nanda Rea Arne Rau Zhiming Cai Huaqing Cheng Francesco Coti Zelati lixin Dai Jingwei Hu Shumei Jia Chichuan Jin Dongyue li Paul O’Brien Rongfeng shen xinwen Shu shengli Sun Xiaojin Sun Xiaofeng Wang Lei Yang Bing Zhang Chen Zhang Shuang-Nan Zhang Yonghe Zhang Jie An David Buckley Alexis Coleiro Bertrand Cordier liming Dou Rob Eyles-Ferris Zhou Fan Hua Feng Shaoyu Fu Johan P.U.Fynbo Lluis Galbany Saurabh W.Jha Shuaiqing Jiang Albert Kong Erik Kuulkers Weihua Lei Wenxiong li Bifang liu Mingjun liu Xing liu Yuan liu Zhu liu Chandreyee Maitra Alessio Marino Itumeleng Monageng Kirpal Nandra Jeremy Sanders Roberto Soria lian Tao Junfeng Wang Song Wang Tinggui Wang Zhongxiang Wang Qingwen Wu Xuefeng Wu Dong Xu Yanjun Xu Suijian Xue Yongquan Xue Zijian Zhang Zipei Zhu Hu Zou Congying Bao Fansheng Chen Houlei Chen Tianxiang Chen Wei Chen Yehai Chen Yifan Chen Chenzhou Cui Weiwei Cui Yanfeng Dai Dongwei Fan Ju Guan Dawei Han Dongjie Hou Haibo Hu Maohai Huang Jia Huo Zhenqing Jia Bowen Jiang Ge Jin Chengkui li Junfei li Longhui li Maoshun li Wei li Zhengda li Tianying lian Congzhan liu Heyang liu Huaqiu liu Fangjun Lu Laidan Luo Jia Ma Xuan Mao Haiwu Pan Xin Pan liming Song Hui Sun Yunyin Tan Qingjun Tang Yihan Tao Hao Wang Juan Wang Lei Wang Wenxin Wang Yilong Wang Yusa Wang Qinyu Wu Haitao Xu Jingjing Xu Xinpeng Xu Yunfei Xu Zhao Xu Changbin Xue Yulong Xue Ailiang Yan Haonan Yang Xiongtao Yang Yanji Yang Juan Zhang Mo Zhang Wenjie Zhang Zhen Zhang Zhen Zhang Ziliang Zhang Donghua Zhao Haisheng Zhao Xiaofan Zhao Zijian Zhao Hongyan Zhou Yilin Zhou Yuxuan Zhu Zhencai Zhu National Astronomical Observatories Chinese Academy of Sciences School of Astronomy and Space Sciences University of Chinese Academy of Sciences Key Laboratory of Particle Astrophysics Institute of High Energy Physics Chinese Academy of Sciences Institute of Space Sciences (ICE) CSIC Institut d’Estudis Espacials de Catalunya (IEEC) Max Planck Institute for Extraterrestrial Physics Innovation Academy for Microsatellites Chinese Academy of Sciences Department of Physics University of Hong Kong School of Physics and Astronomy University of Leicester School of Physics and Astronomy Sun Yat-sen University Department of Physics Anhui Normal University Shanghai Institute of Technical Physics Chinese Academy of Sciences Physics Department Tsinghua University Nevada Center for Astrophysics University of Nevada Las Vegas Department of Physics and Astronomy University of Nevada Las Vegas South African Astronomical Observatory Department of Astronomy University of Cape Town Department of Physics University of the Free State Université Paris Cité CNRS Astroparticule et Cosmologie Université Paris Cité CEA Paris-Saclay IRFU/DAp-AIM Department of Astronomy Guangzhou University Cosmic Dawn Center (DAWN) Niels Bohr Institute University of Copenhagen Department of Physics and Astronomy Rutgers the State University of New Jersey Institute for Cosmic Ray Research The University of Tokyo ESA/ESTEC Department of Astronomy School of Physics Huazhong University of Science and Technology INAF-Osservatorio Astrofisico di Torino Sydney Institute for Astronomy School of Physics The University of Sydney Department of Astronomy Xiamen University Institute for Frontiers in Astronomy and Astrophysics Beijing Normal University Department of Astronomy University of Science and Technology School of Astronomy and Space Sciences University of Science and Technology of China Institute of Deep Space Sciences Deep Space Exploration Laboratory Department of Astronomy School of Physics and Astronomy Yunnan University Shanghai Astronomical Observatory Chi

We report the discovery of a peculiar X-ray transient,EP240408a,by Einstein Probe （EP） and follow-up studies made with EP,Swift,NICER,GROND,ATCA and other ground-based multiwavelength *** new transient was first detected with Wide-field X-ray Telescope （WXT） on board EP on April 8th,2024,manifested in an intense yet brief X-ray flare lasting for *** flare reached a peak flux of 3.9×10-9erg cm-2s-1in 0.5-4 ke V,～300 times brighter than the underlying X-ray emission detected throughout the *** and more precise follow-up observations by EP/FXT,Swift and NICER confirmed the finding of this new *** X-ray spectrum is non-thermal in 0.5-10 ke V,with a power-law photon index varying *** X-ray light curve shows a plateau lasting for ～4 d,followed by a steep decay till becoming undetectable ～10 d after the initial *** on its temporal property and constraints from previous EP observations,an unusual timescale in the range of 7-23 d is found for EP240408a,which is intermediate between the commonly found fast and long-term *** counterparts have been found in optical and near-infrared,with the earliest observation at 17 h after the initial X-ray detection,suggestive of intrinsically weak emission in these *** demonstrate that the remarkable properties of EP240408a are inconsistent with any of the transient types known so far,by comparison with,in particular,jetted tidal disruption events,gamma-ray bursts,X-ray binaries and fast blue optical *** nature of EP240408a thus remains an *** suggest that EP240408a may represent a new type of transients with intermediate timescales of the order of～10 *** detection and follow-ups of more of such objects are essential for revealing their origin.

关键词： X-ray transients ${\bm~{Einstein~~Probe}}$

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Contribution of Temperature Increase to Restrain the Transmission of COVID-19

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The Innovation 2021年第1期2卷 74-81页

作者： Mengyuan Ren Rongjuan Pei Bahabaike Jiangtulu Junxi Chen Tao Xue Guofeng shen Xiaoru Yuan Kexin li Changxin Lan Zhen Chen xinwen Chen Yun Wang Xiaoqian Jia Zewu li Audil Rashid Tippawan Prapamontol Xiuge Zhao Zhaomin Dong Yali Zhang Le Zhang Rongwei Ye Zhiwen li Wuxiang Guan Bin Wang Institute of Reproductive and Child Health Peking University/Key Laboratory of Reproductive HealthNational Health Commission of the People's Republic of ChinaBeijing 100191P.R.China Department of Epidemiology and Biostatistics School of Public HealthPeking UniversityBeijing 100191P.R.China Wuhan Institute of Virology Center for Biosafety Mega-ScienceChinese Academy of SciencesWuhanHubeiChina College of Urban and Environmental Sciences Peking UniversityBeijing 100871P.R.China Key Laboratory of Machine Perception(Ministry of Education) and School of EECSPeking UniversityBeijingChina Institute of Geographic Sciences and Natural Resources Research CASBeijing 100101P.R.China Faculty of Science Botany DepartmentUniversity of GujratHafiz Hayat CampusGujrat-50700Pakistan Research Institute for Health Sciences Chiang Mai UniversityChiang Mai 50200Thailand State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental SciencesBeijing 100012P.R.China Beijing Advanced Innovation Center for Big Data-Based Precision Medicine Beihang UniversityBeijing 100191China

The COVID-19 outbreak has already become a global pandemic and containing this rapid worldwide transmission is of great *** impacts of temperature and humidity on the COVID-19 transmission rate are still under ***,we elucidated these relationships by utilizing two unique scenarios,repeated measurement and natural experiment,using the COVID-19 cases reported from January 23–February 21,2020,in *** modeling results revealed that higher temperature was most strongly associated with decreased COVID-19 transmission at a lag time of 8 *** humidity(RH)appeared to have only a slight *** findings were verified by assessing SARSCoV-2 infectivity under the relevant conditions of temperature(4C–37C)and RH(>40%).We concluded that temperature increase made an important,but not determined,contribution to restrain the COVID19 outbreak in *** suggests that the emphasis of other effective controlling polices should be strictly implemented to restrain COVID19 transmission in cold seasons.

关键词： restrain humidity COV

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Surveillance of Lung Tuberculosis for Immigrants from 1993 to 1995

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旅行医学科学 1996年第1期2卷 3-5页

作者： Feng xinwen shen Jingsheng li Yan Guang Zhou Health Bureau, P. R. China

This paper reports the surveillance results of Lung Tuberculosis（LTB）for im migrants examined at the Health Service Center for International Traveler of Guangzhou H&Q from 1993 to 1995,166 cases whose chest films showed active LTB among 30,019 persons. The detecking rate of chest film was 553/104。16 cases of active LTB patients were posetive sputum smear or culture,defined as infectious LTB（Class A）. 150 cases were noninfectious active LTB（Class B1）. The author analyses the surveillance results of LTB for immigrants and suggested some improving method.

关键词： lung tuberculosis surveillance active tuberculosis infectious tuberculosis

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页岩气储层缝网压裂理论与技术研究新进展

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天然气工业 2018年第3期38卷 1-14页

作者：赵金洲任岚沈骋李勇明 "油气藏地质及开发工程"国家重点实验室.西南石油大学

为破解页岩气开发技术的瓶颈,借鉴北美地区页岩气开发已取得的成果与经验,基于我国自2005年来页岩气开发技术的探索与实践认识,并结合最新的研究成果,综合分析了页岩气储层缝网可压性评价、缝网扩展机理、压裂改造体积评价、压裂液研制... 详细信息

为破解页岩气开发技术的瓶颈,借鉴北美地区页岩气开发已取得的成果与经验,基于我国自2005年来页岩气开发技术的探索与实践认识,并结合最新的研究成果,综合分析了页岩气储层缝网可压性评价、缝网扩展机理、压裂改造体积评价、压裂液研制等方面的理论新进展,主要包括:页岩脆性从建立矿物、力学的半定量门限值测定发展到整合了岩石组分、弹性力学、天然裂缝发育特征的综合评价;缝网扩展从定向延伸理论发展到随机天然裂缝分布下的缝网形成模拟;储层改造体积从依赖微地震监测等仪器技术发展到依托于离散裂缝网络、扩展有限元的数学理论评价方法 ;压裂液从滑溜水(减阻水)和线性胶压裂液体系的泛用到少水或无水等新型压裂液的研制与应用。在此基础上,指出了页岩气储层缝网可压裂性综合评价、深层页岩气压裂、页岩气压裂施工曲线诊断、页岩气重复压裂理论、新型压裂液体系研制及其返排控制等理论和技术所面临的挑战,并预测了相关技术的发展趋势,以期为我国后续页岩气高效开发提供理论与技术指导。

关键词：中国页岩气储集层缝网压裂可压性缝网扩展改造体积压裂液研究进展

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反思与展望:中国“乡村治理”研究评估(2004-2014)

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中国科技论坛 2017年第4期 157-163页

作者：沈费伟刘祖云李永明南京农业大学公共管理学院江苏南京210095 南京农业大学信息科技学院江苏南京210095

本文以知识图谱和文献统计的方法对2004—2014年十大学术期刊的乡村治理研究成果进行了评估。研究发现,当前乡村治理研究存在着欠缺统一的学术规范,导致重复性、非学术性研究偏多;研究类型存在结构性失衡,不能形成真正的学术平台;变量... 详细信息

本文以知识图谱和文献统计的方法对2004—2014年十大学术期刊的乡村治理研究成果进行了评估。研究发现,当前乡村治理研究存在着欠缺统一的学术规范,导致重复性、非学术性研究偏多;研究类型存在结构性失衡,不能形成真正的学术平台;变量统计研究明显短缺,研究尚处于较低阶段;学科方法论研究被严重忽略,难以构建起完整的理论体系。因此,在未来的村治研究中,必须不断强化问题意识和方法论意识,通过注重本土化理论建构和拥有全球视野相结合,从而实现乡村治理研究高质量发展。

关键词：乡村治理学术期刊研究评估本土化视角全球性视野

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