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Exploration of the mechanism of cavitation vortex rope and vortex development in the draft tube of tubular turbine units

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International Journal of Agricultural and Biological Engineering 2024年第1期17卷 163-171,F0002页

作者： Chuang Cheng Zhenggui Li Changrong Shen Shenglong Gu Chuchu Zeng Chuanzheng Bai Meng Liu Junfeng Hu Qinghai University of Science and Technology Xining 810000China Key Laboratory of Fluid and Power Machinery Ministry of Education(Xihua University)Chengdu 610039China south-to-north water Diversion East Jiangsu water Source Co. Ltd.Nanjing 210029China School of civil engineering and water resources Qinghai UniversityXining 810016China Dongyuan Branch of Shenzhen water planning and Design Institute Co. Ltd.Changsha 410000China

Draft tube vortex rope is considered a special cavitation flow phenomenon in tubular turbine *** vortex rope is one of the most detrimental factors affecting the safety of hydraulic *** this study,ANSYS CFX software was utilized to numerically simulate the internal cavitation flow of a hydraulic turbine draft *** evolution of the cavitation vortex core was characterized by vortex line distribution and vorticity transport *** shape and number of blades influenced the revolving direction and distribution characteristics of the vortex close to the runner cone,which formed a counterclockwise-clockwise-counterclockwise distribution ***,there were many secondary flows in the draft *** cancellation and dissipation between the flows was one of the reasons for reduction in *** the cross-sectional shape of the draft tube was changed,the vorticity was distributed from the center of the vortex rope to all parts of the cross-sectional draft tube,with extreme values at the center and at the *** vortex stretching and dilatation terms played a major role in the change in vorticity,with the baroclinic torque having an effect at the center of the vortex rope,this study is helpful to understand the flow of water in the draft tube and guide the design and optimization of the draft tube in engineering application.

关键词： cavitation vortex rope vorticity transport equation vortex line draft tube

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Experimental and theoretical analysis of loading characteristics of electret fi lter media for charged particles

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PARTICUOLOGY 2024年第10期93卷 87-98页

作者： Cai, Yiqi Cai, Rongrong Zhang, Lizhi south China Univ Technol Sch Chem & Chem Engn Key Lab Enhanced Heat Transfer & Energy Conservat Educ Minist Guangzhou 510640 Peoples R China south China Univ Technol State Key Lab Subtrop Bldg Sci Guangzhou 510640 Peoples R China

The degradation of filtration performance in electret filter media during usage poses a significant challenge. Pre-charging of aerosols has been identified as an effective method to mitigate this issue. However, the effects of particle charging characteristics on the loading characteristics of electret filters still need a comprehensive understanding. In this study, a needle-cylinder corona charger was employed to pre-charge aerosols, and the particle charge state was determined by multiphysics simulation. The effects of particle charge polarity and charge quantity on the loading performance of the electret filter were quantitatively investigated. The results showed that the particle charge polarity had a negligible impact on the loading performance under the condition of the equivalent particle charge quantity. In addition, the charged particles effectively improved the efficiency degradation during the loading process of electret media, with higher charge quantities resulting in more pronounced improvements. The electrostatic attenuation factor showed a negative exponential correlation with the particle charge quantity. This was attributed to the uneven particle deposition on fiber surface due to the attraction of charged particles by the opposite charges on the electret fibers, which alleviated the effect of electrostatic shielding. (c) 2024 Published by Elsevier B.V. on behalf of Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences.

关键词： Electret filter Charged particles Loading characteristic Corona charging Electrostatic screening NUMERICAL-SIMULATION FILTER FILTRATION AEROSOL PERFORMANCE COLLECTION TRANSPORT MODEL

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Urban Flood Mitigation Strategies with Coupled Gray–Green Measures: A Case Study in Guangzhou City, China

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International Journal of Disaster Risk Science 2024年第3期15卷 467-479页

作者： Jiayue Li Jiajun Zeng Guoru Huang Wenjie Chen School of Civil Engineering and Transportation South China University of Technology School of Architecture South China University of Technology State Key Laboratory of Subtropical Building and Urban Science South China University of Technology College of water Conservancy and Civil Engineering South China Agricultural University

The integration of gray and green infrastructure has proven to be a feasible approach for managing stormwater in established urban areas. However, evaluating the specific contributions of such coupled strategies is challenging. This study introduced a novel integrated hydrological-hydrodynamic model that takes into account the layout of low-impact development(LID)facilities along with pipeline alignment and rehabilitation. Reliable results from modeling were used to assess the individual contribution of LID and improved drainage facilities to urban flooding mitigation. We selected a natural island in Guangzhou City, China, as the study site. The results indicate that combining three LID measures, namely green roofs, sunken green spaces, and permeable pavements, can reduce total runoff by 41.7% to 25.89% for rainfall recurrence periods ranging from 1year to 100 years, and decrease the volume of nodal overflow by nearly half during rainfall events of less than 10-year return period. By integrating LID measures with the upgraded gray infrastructure, the regional pipeline overloading condition is substantially alleviated, resulting in a significant improvement in pipeline system resilience. For urban flooding control, it is recommended to integrate sufficient green space and avoid pipe-laying structural issues during urban planning and construction. The findings may assist stakeholders in developing strategies to best utilize gray and green infrastructure in mitigating the negative eff ects of urban flooding.

关键词： Coupled hydrodynamic model Gray–green approach Guangzhou City LID Pipe renovation Urban inundation

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Contributors to tidal duration asymmetry with varied coastline configurations on western shelf of Yellow Sea

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water Science and Engineering 2024年第1期17卷 1-12页

作者： Xi Feng Zheng Li Hui Feng Jia-yan Yang Shou-peng Xie Wei-bing Feng College of Harbor.Coastal and Offshore Engineering Hohai UniversityNanjing 210098China China Harbour Engineering Co. LtdBeijing 100027China Key Laboratory of Port Waterway and Sedimentation Engineering of the Ministry of CommunicationsNanjing 210029China China south-to-north water Diversion Corporation Limited Beijing 100036China

Coastal management in China is confronted with an urgent choice between natural restoration and maintenance of existing seawalls and reclaimed land for economic development.A key criterion for making this decision is the resilience to coastal flooding,which depends on the ability to predict tidal *** duration asymmetry(TDA)is a key parameter in determination of the arrival and duration of flood *** study selected the western inner shelf of the Yellow Sea(WYS)as the study area and investigated the responses of TDA to different shoreline configurations and relative sea level *** responses of TDA to shoreline reconstruction yielded spatial variability locally and *** the nearshore area,the responses of TDA to the complex ocean environment mainly originated from the combined functions of reflection,bottom friction,and advection,which controlled the energy transfer from M2 or S2 constituents to their overtides or compound *** sensitivity of TDA to coastline typologies was not limited to coastal waters but could stretch over the entire inner *** vulnerability of tidal responses was due to the displacement of the M2 amphidrome of the Kelvin wave on the WYS,which in turn changed tidal energy fluxes over the *** relative sea level rise could intensify the feedback of TDA to seawalls and land reclamation.

关键词： Tidal duration asymmetry Western inner shelf of Yellow Sea Natural restoration Relative sea level rise Tidal amphidrome

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Analyzing the spatiotemporal evolution and driving forces of gross ecosystem product in the upper reaches of the Chaobai River Basin

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Frontiers of Environmental Science & Engineering 2024年第8期18卷 117-132页

作者： Jiacheng Li Qi Han Liqiu Zhang Li Feng Guihuan Liu Beijing Key Laboratory for Source Control Technology of water Pollution College of Environmental Science and EngineeringBeijing Forestry UniversityBeijing 100083China Engineering Research Center for water Pollution Source Control&Eco-remediation College of Environmental Science and EngineeringBeijing Forestry UniversityBeijing 100083China Center of Eco-compensation Chinese Academy of Environmental PlanningMinistry of Ecology of EnvironmentBeijing 100041China

The Chaobai River Basin,which is a crucial ecological barrier and primary water source area within the Beijing-Tianjin-Hebei region,possesses substantial ecological *** gross ecosystem product(GEP)in the Chaobai River Basin is a reflection of ecosystem conditions and quantifies nature’s contributions to humanity,which provides a basis for basin ecosystem service management and *** study investigated the spatiotemporal evolution of GEP in the upper Chaobai River Basin and explored the driving factors influencing GEP spatial *** patterns from 2005 to 2020 were analyzed,and GEP was calculated for 2005,2010,2015,and *** driving factors influencing GEP spatial differentiation were identified using the optimal parameter-based geographical detector(OPGD)*** key findings are as follows:(1)From 2005 to 2020,the main ecosystem types were forest,grassland,and *** areas experienced significant changes,and conversions mainly occurred among urban,water,grassland and agricultural ecosystems.(2)Temporally,the GEP in the basin increased from 2005 to 2020,with regulation services *** the county(district)scale,GEP exhibited a north-west-high and south-east-low pattern,showing spatial differences between per-unit-area GEP and county(district)GEP,while the spatial variations in per capita GEP and county(district)GEP were similar.(3)Differences in the spatial distribution of GEP were influenced by regional natural geographical and socioeconomic *** these factors,gross domestic product,population density,and land-use degree density contributed *** among different driving forces noticeably impacted GEP spatial *** findings underscore the necessity of incorporating factors such as population density and the intensity of land-use development into ecosystem management decision-making processes in the upper reaches of the Chaobai River *** policies

关键词： Ecosystem pattern Gross ecosystem product(GEP) Spatiotemporal evolution Optimal parameter-based geographical detector(OPGD) Chaobai River Basin

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A general synthetic strategy for N, P co-doped graphene supported metal-rich noble metal phosphides for hydrogen generation

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Green Energy & Environment 2024年第1期9卷 152-162页

作者： Jingwen Ma Xiang Li Guangyu Lei Jun Wang Juan Wang Jian Liu Ming Ke Yang Li Chunwen Sun School of Chemical and Environmental Engineering China University of Mining and Technology(Beijing)Beijing100083China State Key Laboratory of Heavy Oil Processing China University of PetroleumBeijing102249China Lab of Advanced Nano-structures&transfer Processes Department of Chemical EngineeringTianjin UniversityTianjin300354China PetroChina planning and Engineering Institute Beijing100083China

The exploitation of electrocatalysts with high activity and durability for HER is desirable for future energy systems,but it is still a *** have attracted increasing attentions,but the preparation process often needs toxic regents or dangerous reaction ***,we develop a general green method to fabricate metal-rich NMPs anchored on NPG through pyrolyzing DNA cross-linked *** obtained Ru_(2) P-NPG exhibits an ultrasmall overpotential of 7 mV at 10 mA cm^(2) and ultralow Tafel slope of 33 mV dec^(-1) in 1.0 mol L?1 KOH,even better than that of commercial Pt/*** addition,Ru 2 P-NPG also shows low overpotentials of 29 and 78 mV in 0.5 mol L^(-1) H_(2)SO_(4) and 1.0 mol L^(-1) PBS,*** superior activity can be attributed to the ultrafine dispersion of Ru 2 P nanoparticles for more accessible sites,more defects formed for abundant active sites,the two-dimensional plane structure for accelerated electron transfer and mass transport,as well as the regulation of electron distribution of the ***,the synthetic method can also be applied to prepare other metal-rich noble metal phosphides(Pd_(3)P-NPG and Rh_(2)P-NPG),which also exhibits high activity for *** work provides an effective strategy for designing NMP-based electrocatalysts.

关键词： Noble metal phosphides Electrocatalyst Deoxyribonucleic acid Hydrogen evolution pH universal

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Calculation of Mass Concrete Temperature and Creep Stress under the Influence of Local Air Heat transfer

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Computer Modeling in Engineering & Sciences 2024年第9期140卷 2977-3000页

作者： Heng Zhang Chao Su Xiaohu Chen Zhizhong Song Weijie Zhan Academy of Science and Technology Changjiang Institute of Survey Planning Design and ResearchWuhan430010China College of water Conservancy and Hydropower Engineering Hohai UniversityNanjing210098China Chief Engineer Office Wujiang Company of Goupitan Power Construction CooperationYuqing564408China

Temperature-induced cracking during the construction of mass concrete is a significant *** simulations of concrete temperature have primarily assumed that the concrete is placed in an open *** problem of heat transfer between the air and concrete has been simplified to the concrete’s heat dissipation ***,in the case of tubular concrete structures,where air inlet and outlet are relatively limited,the internal air temperature does not dissipate promptly to the external environment as it *** accurately simulate the temperature and creep stress in tubular concrete structures with enclosed air spaces during construction,we establish an air–concrete coupled heat transfer model according to the principles of conjugate heat transfer,and the accuracy of the model is verified through ***,we conduct a case study to analyze the impact of airflow within the ship lock corridor on concrete temperature and creep *** results demonstrate that enhancing airflow within the corridor can significantly reduce the maximum concrete *** with cases in which airflow within the corridor is neglected,the maximum concrete temperature and maximum tensile stress can be reduced by 12.5℃ and 0.7 MPa,respectively,under a wind speed of 4 m/*** results of the traditional calculation method are relatively close to those obtained at a wind speed of 1 m/***,the temperature reduction process in the traditional method is faster,and the method yields greater tensile stress values for the corridor location.

关键词： Conjugate heat transfer temperature field mass concrete creep stress

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Identified the hydrochemical and the sulfur cycle process in subsidence area of Pingyu mining area using multi-isotopes combined with hydrochemistry methods

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Journal of Groundwater Science and Engineering 2024年第1期12卷 62-77页

作者： Hui-Meng Su Fa-Wang Zhang Jing-Yu Hu Jin-Feng Lei Wei Zuo Bo Yang Yu-Hua Liu School of Environmental Studies China University of GeosciencesWuhan 430074China Center for Hydrogeology and Environmental Geology China Geological SurveyBaoding 071051Hebei ProvinceChina Henan Branch China South-to-North Water Diversion Middle Route Corporation LimitedZhengzhou 450046China The Fifth Geological Survey Institute Henan Provincial Bureau of Geology and Mineral ResourcesZhengzhou 450012China Natural Resources Science and Technology Innovation Center of Henan Province(Research on Eco-Environmental Assessment and Restoration Technology) Zhengzhou 450012China

Groundwater serves as an important water source for residents in and around mining *** achieve scientific planning and efficient utilization of water resources in mining areas,it is essential to figure out the chemical formation process and the ground water sulfur cycle that transpire after the coal mining *** on studies of hydrochemistry and D,^(18)O-H_(2)O,^(34)S-SO_(4)isotopes,this study applied principal component analysis,ion ratio and other methods in its attempts to reveal the hydrogeochemical action and sulfur cycle in the subsidence area of Pingyu mining *** study discovered that,in the studied area,precipitation provides the major supply of groundwater and the main water chemistry effects are dominated by oxidation dissolution of sulfide minerals as well as the dissolution of carbonate and silicate *** sulfate in groundwater primarily originates from oxidation and dissolution of sulfide minerals in coal-bearing strata and human *** mixed sulfate formed by the oxidation of sulfide minerals and by human activities continuously recharges the groundwater,promoting the dissolution of carbonate rock and silicate rock in the process.

关键词： PCA Ion ratio water chemistry Sulfide minerals Multi-isotopes Subsidence area of mining area

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Systematic review of the efficacy of data-driven urban building energy models during extreme heat in cities:Current trends and future outlook

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Building Simulation 2024年第5期17卷 695-722页

作者： Nilabhra Mondal Prashant Anand Ansar Khan Chirag Deb David Cheong Chandra Sekhar Dev Niyogi Mattheos Santamouris Department of Architecture and Regional planning Indian Institute of Technology KharagpurKharagpurIndia Department of Geography Lalbaba CollegeUniversity of CalcuttaKolkataIndia School of Architecture Design and PlanningThe University of SydneyAustralia Department of the Built Environment National University of SingaporeSingapore Department of Geological Sciences Jackson School of GeosciencesThe University of Texas at AustinAustinUSA DepartmentofCivil Architecturaland Environmental EngineeringThe Universityof Texas at AustinAustinUSA Faculty of Built Environment University of New South WalesAustralia

Energy demand fluctuations due to low probability high impact(LPHI)micro-climatic events such as urban heat island effect(UHI)and heatwaves,pose significant challenges for urban infrastructure,particularly within urban *** short term load forecasting(STLF)of buildings in urban micro-climatic setting(UMS)is obscured by the complex interplay of surrounding morphology,micro-climate and inter-building energy *** urban building energy modelling(UBEM)approaches to provide quantitative insights about building energy consumption often neglect the synergistic impacts of micro-climate and urban morphology in short temporal *** order modelling,unavailability of rich urban datasets such as building key performance indicators for building archetypes-characterization,limit the inter-building energy dynamics consideration into *** addition,mismatch of resolutions of spatio-temporal datasets(meso to micro scale transition),LPHI events extent prediction around UMS as well as its accurate quantitative inclusion in UBEM input organization step pose another degree of *** review aims to direct attention towards an integrated-UBEM(i-UBEM)framework to capture the building load fluctuation over multi-scale spatio–temporal *** highlights usage of emerging data-driven hybrid approaches,after systematically analysing developments and limitations of recent physical,data-driven artificial intelligence and machine learning(AI-ML)based modelling *** also discusses the potential integration of google earth engine(GEE)-cloud computing platform in UBEM input organization step to(i)map the land surface temperature(LST)data(quantitative attribute implying LPHI event occurrence),(ii)manage and pre-process high-resolution spatio-temporal UBEM *** the potential of digital twin,central structed data models to integrate along UBEM workflow to reduce uncertainties related to building archetype characterizat

关键词： urban heat island(UHI) urbanmicro-climate urban morphology urban building energy modelling(UBEM) digitaltwin shorttermload forecasting(STLF) googleearthengine(GEE)

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D-A-D-structured boron-dipyrromethene with aggregation-induced enhanced phototherapeutic efficiency for near-infrared fluorescent and photoacoustic imaging-guided synergistic photodynamic and photothermal cancer therapy

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Chinese Chemical Letters 2024年第10期35卷 325-330页

作者： Xuejian Xing Pan Zhu E Pang Shaojing Zhao Yu Tang Zheyu Hu Quchang Ouyang Minhuan Lan Key Laboratory of Hunan Province for water Environment and Agriculture Product Safety College of Chemistry and Chemical Engineering Central South University School of Chemistry and Chemical Engineering Neijiang Normal University Medical Department of Breast Cancer Hunan Cancer Hospital Medical Department of Breast Cancer The Affiliated Cancer Hospital of Xiangya School of Medicine Central South University

Clinical phototheranostic agents suffer from low absorption in near-infrared（NIR） region, decreasing singlet oxygen quantum yield（1O2QY） caused by aggregation in water, and low photothermal conversion efficiency（PCE）, all of which are factors weakening their phototheranostic efficacy. Herein, we designed and synthesized a donor-acceptor-donor（D-A-D） structured boron-dipyrromethene derivative（B-2TPA） which exhibited NIR absorption and fluorescence. After being encapsulated in amphiphilic distearoyl phosphoethanolamine polyethyleneglycol 2000（DSPE-PEG-2000）, the water-soluble B-2TPA nanoparticles（NPs）had increasing1O2QY（6.7%） due to the intermolecular aggregation-induced decrease in the energy gap between singlet and triplet excited states. Moreover, the quenched fluorescence and stable twisted intramolecular charge transfer in aggregates further increased the PCE of B-2TPA NPs to 60.1%. In vitro and in vivo studies confirmed that B-2TPA NPs could be used in NIR fluorescence and photoacoustic imagingguided synergistic photodynamic and photothermal therapy in tumor treatment.

关键词： Aggregation Boron-dipyrromethene Intersystem crossing Photodynamic therapy Photothermal therapy Twisted intramolecular charge transfer

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