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Spatial and temporal variation of water clarity in typical reservoirs in the Beijing-Tianjin-Hebei region observed by GF 1-WFV satellite data

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Journal of Oceanology and Limnology 2024年第4期42卷 1048-1060页

作者： Chang CAO Junsheng LI Xiaodong JIA Shenglei wang Bo wan Liaoning earthquake Agency Shenyang 11000China Key Laboratory of Digital earth Science Aerospace Information Research InstituteChinese Academy of SciencesBeijing 100094China International Research Center of Big Data for Sustainable Development Goals Beijing 100094China School of electronic Electrical and Communication EngineeringUniversity of Chinese Academy of SciencesBeijing 100049China

Rapidly monitoring regional water quality and the changing trend is of great practical and scientific significance,especially for the Beijing-Tianjin-Hebei(BTH)region of China where water resources are relatively scarce and inland water bodies are generally *** remote sensing data of the GF 1 satellite launched in 2013 have characteristics of high spatial and temporal resolution,which can be used for the dynamic monitoring of the water environment in small lakes and ***,the water quality remote sensing monitoring model based on the GF 1 satellite data for lakes and reservoirs in BTH is still lacking because of the considerable differences in the optical characteristics of the lakes and *** this paper,the typical reservoirs in BTH-Guanting Reservoir,Yuqiao Reservoir,Panjiakou Reservoir,and Daheiting Reservoir are taken as the study *** the atmospheric correction of GF 1-WFV,the relative radiation normalized atmospheric correction was adopted after comparing it with other methods,such as 6 S and *** the water clarity retrieval,a water color hue angle based model was proposed and outperformed other available published models,with the R 2 of 0.74 and MRe of 31.7%.The clarity products of the four typical reservoirs in the BTH region in 2013-2019 were produced using the GF 1-WFV *** on the products,temporal and spatial changes in clarity were analyzed,and the main influencing factors for each water body were *** was found that the clarity of Guanting,Daheiting,and Panjiakou reservoirs showed an upward trend during this period,while that of Yuqiao Reservoir showed a downward *** the influencing factors,the water level of the water bodies can be an important factor related to the water clarity changes in this region.

关键词： GF 1 satellite atmospheric correction clarity Beijing-Tianjin-Hebei spatial and temporal change analysis

Numerical investigation of sinusoidal pulsating gas intake to intensify the gas-slag momentum transfer in the top-blown smelting furnace

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International Journal of Minerals,Metallurgy and Materials 2024年第2期31卷 301-314页

作者： Zhanghao wan Shiliang Yang Desong Kong Dongbo Li Jianhang Hu Hua wang State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization Kunming University of Science and TechnologyKunming 650093China Southwest Copper Branch Yunnan Copper Co.Ltd.Kunming 650102China

The variation characteristics of bubble morphology and the thermal-physical properties of bubble boundary in the top-blown smelting furnace were explored by means of the computational fluid dynamics *** essential aspects of the fluid phase(e.g.,splashing volume,dead zone of copper slag,and gas penetration depth)were explored together with the effect of sinusoidal pulsating gas intake on the momentum-transfer performance between *** results illustrated that two relatively larger vortices and two smaller vortices appear in the bubble waist and below the lance,*** expansion of larger ones as well as the shrinking of smaller ones combine to cause the contraction of the bubble *** to the results of the case with a fixed gas injection velocity(V_(g)=58 m/s),the splashing volume and dead zone volume of the slag under the V_(g)=58+10sin(2πt)condition are reduced by 24.9%and 23.5%,respectively,where t represents the instant *** penetration depth and slag motion velocity of the latter are 1.03 and 1.31 times high-er than those of the former,respectively.

关键词： top-blown smelting furnace pulsed flow volume of fluid penetration depth splashing volume

Predicting PM_(2.5) Concentration in the Yangtze River Delta Region Using Climate System Monitoring Indices and Machine Learning

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Journal of Meteorological Research 2024年第2期38卷 249-261页

作者： Jinghui MA Shiquan wan Shasha XU Chanjuan wang Danni QIU Shanghai Typhoon Institute Shanghai Meteorological ServiceShanghai 200030 Key Laboratory of Polar Atmosphere-Ocean-Iice System for Weather and Climate Ministry of EducationDepartment of Atmospheric and Oceanic SciencesFudan UniversityShanghai 200438 Shanghai Key Laboratory of Meteorology and Health Shanghai Meteorological ServiceShanghai 200030 Yangzhou Meteorological Office Yangzhou 225001 Department of Physics Yangzhou UniversityYangzhou 225003

Changing meteorological conditions during autumn and winter have considerable impact on air quality in the Yangtze River Delta(YRD)*** climatic factors,such as sea surface temperature and sea ice,together with the atmospheric circulation,directly affect meteorological conditions in the YRD region,thereby modulating the variation in atmospheric PM_(2.5) *** study used the evolutionary modeling machine learning technique to investigate the lag relationship between 144 climate system monitoring indices and autumn/winter PM_(2.5) concentration over 0-12 months in the YRD *** calculating the contribution ratios and lagged correlation coefficients of all indices over the previous 12 months,the top 36 indices were selected for model ***,the nine indices that contributed most to the PM_(2.5) concentration in the YRD region,including the decadal oscillation index of the Atlantic Ocean and the consistent warm ocean temperature index of the entire tropical Indian Ocean,were selected for physical mechanism *** evolutionary model was developed to forecast the average PM_(2.5) concentration in major cities of the YRD in autumn and winter,with a correlation coefficient of *** model testing,the correlation coefficient between the predicted and observed PM_(2.5) concentrations was in the range of 0.73-0.83 and the root-mean-square error was in the range of 9.5-11.6μg m-3,indicating high predictive *** model performed exceptionally well in capturing abnormal changes in PM_(2.5) concentration in the YRD region up to 50 days in advance.

关键词： PM_(2.5)concentration machine learning evolutionary modeling seasonal prediction

2D–3D dual carbon layer confined ultrasmall VN nanoparticles for improving lithium-ion storage in hybrid capacitors

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Rare Metals 2024年第1期43卷 65-75页

作者： Zhao-Wei Hu Hui-Fang Li Peng wang wan-Li wang Lei Yang Xiao-Jun wang Zhi-Ming Liu College of electromechanical engineering Shandong Engineering Laboratory for Preparation and Application of High-Performance Carbon-MaterialsQingdao University of Science&TechnologyQingdao 266061China Research Center for Intelligent and Wearable Technology College of Textiles and ClothingQingdao UniversityQingdao 266071China

Lithium-ion capacitors(LICs) of achieving high power and energy density have garnered significant attention. However, the kinetics unbalance between anode and cathode can impede the application of LICs. Vanadium nitride(VN) with a high theoretical specific capacity(~ 1200 m Ah·g^(-1)) is a better pseudocapacitive anode to match the response of cathode in LICs. However, the insertion/extraction of Li-ions in VN's operation results in significant volume expansion. Herein, the VN/N-r GO-5composite that three-dimentional(3D) dicyandiamidederived-carbon(DDC) tightly wrapped VN quantum dots(VN QDTs) on two-dimentional(2D) reduced graphene oxid(r GO) was prepared by a facile strategy. The VN QDTs can reduce ion diffusion length and improve charge transfer kinetics. The 2D r GO as a template provides support for nanoparticle dispersion and improves electrical conductivity. The 3D DDC tightly encapsulated with VN QDTs mitigates agglomeration of VN particles as well as volume expansion. Correspondingly, the LICs with VN/Nr GO-5 composite as anode and activated carbon(AC) as cathode were fabricated, which exhibits a high energy density and power density. Such strategy provides a perspective for improving the electrochemical properties of LIC anode materials by suppressing volume expansion and enhancing conductivity.

关键词： Vanadium nitride(VN)quantum dots Reduced graphene oxide(rGO)nanosheets Dicyandiamide-derived-carbon 2D–3D dual carbon layer Lithium-ion capacitors

Numerical simulation of liquid sloshing in a spherical tank by MPS method

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Journal of Hydrodynamics 2024年第2期36卷 232-240页

作者： Cong-yi Huang Ji-fei wang Wei-wen Zhao De-cheng wan Computational Marine Hydrodynamic Lab(CMHL) School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China Shanghai Aerospace System engineering Institute Shanghai201109China

This paper investigates the sloshing phenomena in a spherical liquid tank using the moving particle semi-implicit(MPS)method,a crucial study in fluid *** from previous research focused on rectangular or LNG tanks,this work explores the unique motion patterns inherent to spherical *** accuracy of our in-house MPS solver MLParticle-SJTU is validated against experimental data and finite volume method(FVM).And the MPS method reveals a closer alignment with experimental outcomes,which suggests that MPS method is particularly effective for modeling complex,non-linear fluid *** the fluid’s response to excitation at its natural frequency is simulated,showcasing vigorous sloshing and rotational *** analyses of the fluid motion are conducted by drawing streamline diagrams,velocity vector diagrams,and vorticity *** fluid’s motion response is explored using both time-domain and frequency-domain curves of the fluid centroid,as well as the sloshing force.

关键词： Moving particle semi-implicit(MPS)method spherical tank liquid sloshing model experiment

Structural parameter optimization of a furrow opener based on eDeM software

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International Journal of Agricultural and Biological engineering 2024年第3期17卷 115-120页

作者： Longjie wang Bin Zhou Chang wan Ling Zhou College of Mechanical and electrical engineering Tarim UniversityAlar 843300XinjiangChina Modern Agricultural engineering Key Laboratory at Universities of education Department of Xinjiang Uygur Autonomous Region Alar 843300XinjiangChina Xinjiang Production and Construction Corps(XPCC)Key Laboratory of Utilization and equipment of Special Agricultural and Forestry Products in Southern Xinjiang Alar 843300XinjiangChina

To reduce the ditching resistance of a furrow opener during operation,single-factor and multiple-factor combinations were used to explore the influence of the furrow opener’s advance speed,blade opening angle,and width on the ditching resistance based on the discrete element method(DeM).A DeM simulation of the furrow opener was *** changing these influencing factors,the parameters with the least resistance to operation were *** openers were fabricated according to the optimized results,and soil trench tests were carried *** and soil groove tests showed that the minimum ditching resistance was 58.54 N when the current advance speed was 4.47 m/s,the blade opening angle was 32.02°,and the furrow opener width was 51.45 *** error between the simulated value of the ditching resistance and the soil trench test was within 10%,and the trends of resistance change were essentially the same,indicating that it is feasible to optimize the structural parameters of a trench furrow opener using *** research results can provide a reference for the parameter optimization of furrow openers.

关键词： furrow opener discrete element optimization ditching resistance

Insights into the role of oxygen-containing functional groups on carbon surface in water–electricity generation

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Nano Research 2024年第7期17卷 6645-6653页

作者： wan Xue Zongbin Zhao Honghui Bi Bolun Zhang Xuzhen wang Jieshan Qiu State Key Laboratory of Fine Chemicals Liaoning Key Laboratory for Energy Materials and Chemical EngineeringSchool of Chemical EngineeringDalian University of TechnologyDalian 116024China State Key Laboratory of Fine Chemicals Liaoning Key Laboratory for Energy Materials and Chemical EngineeringSchool of ChemistryDalian University of TechnologyDalian 116024China State Key Laboratory of Chemical Resource engineering College of Chemical EngineeringBeijing University of Chemical TechnologyBeijing 100029China

A deep understanding of the electricity generation mechanism from the interaction between water molecules and carbon material surfaces is attractive for next-generation water-based energy conversion and storage ***,an asymmetric generator was assembled based on functionalized carbon nanotubes films to investigate the relative contribution from various oxygen functional groups on carbon surface to the water-electrical *** and calculations demonstrate that the electricity mainly originates from the water molecule adsorption by carboxyl groups and dissociation of functional groups on carbon surface,which leads to the formation of electrical double layers at *** device allows the electricity generation with a variety of water sources,such as deionized water,tap water,as well as *** particular,the generator based on carboxyl carbon nanotubes can induce a voltage of over 200 mV spontaneously in natural seawater with the power density of about 0.11 mW·g^(−1).High voltages can be achieved easily through the series-connection strategy to power electronic products such as a liquid crystal *** work reveals the dominant role of carboxyl groups in carbon-based water–electricity conversion and is expected to offer inspiration for the preparation of carbon materials with high electrical performance.

关键词： electricity generation water adsorption dissociation carboxyl groups carbon nanotubes

Graph Convolutional Networks embedding Textual Structure Information for Relation extraction

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Computers, Materials & Continua 2024年第5期79卷 3299-3314页

作者： Chuyuan Wei Jinzhe Li Zhiyuan wang Shanshan wan Maozu Guo School of electrical and Information engineering Beijing University of Civil Engineering and ArchitectureBeijing102616China

Deep neural network-based relational extraction research has made significant progress in recent years,andit provides data support for many natural language processing downstream tasks such as building knowledgegraph,sentiment analysis and question-answering ***,previous studies ignored much unusedstructural information in sentences that could enhance the performance of the relation extraction ***,most existing dependency-based models utilize self-attention to distinguish the importance of context,whichhardly deals withmultiple-structure *** efficiently leverage multiple structure information,this paperproposes a dynamic structure attention mechanism model based on textual structure information,which deeplyintegrates word embedding,named entity recognition labels,part of speech,dependency tree and dependency typeinto a graph convolutional ***,our model extracts text features of different structures from theinput *** Structure information Graph Convolutional Networks employs the dynamic structureattention mechanism to learn multi-structure attention,effectively distinguishing important contextual features invarious structural *** addition,multi-structure weights are carefully designed as amergingmechanismin the different structure attention to dynamically adjust the final *** paper combines these featuresand trains a graph convolutional network for relation *** experiment on supervised relation extractiondatasets including Semeval 2010 Task 8,TACReD,TACReV,and Re-TACeD,the result significantly outperformsthe previous.

关键词： Relation extraction graph convolutional neural networks dependency tree dynamic structure attention

Numerical Study on the Aerodynamic and Fluid−Structure Interaction of An NReL-5MW Wind Turbine

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China Ocean engineering 2024年第3期38卷 363-378页

作者： ZHAO Mi YU wan-li wang Pi-guang QU Yang DU Xiu-li Key Laboratory of Urban Security and Disaster engineering of Ministry of education Beijing University of TechnologyBeijing 100124China State Key Laboratory of Bridge engineering Safety and Resilience Beijing University of TechnologyBeijing 100124China

A 5-MW wind turbine has been modeled and analyzed for fluid-structure interaction and aerodynamic *** this study, a full-scale model of a 5-MW wind turbine is first developed based on a computational fluid dynamics(CFD) approach, in which the unsteady, noncompressible Reynolds Averaged Navier-Stokes(RANS) method is used. The main focus of the study is to analyze the tower shadow effect on the aerodynamic performance of the wind turbine under different inlet flow conditions. Subsequently, the finite element model is established by considering fluid/structure interactions to study the structural stress, displacement, strain distributions and flow field information of the structure under the uniform wind speed. Finally, the fluid-structure interaction model is established by considering turbulent wind and the tower shadow effect. The variation rules of the dynamic response of the one-way and two-way fluid-structure interaction(FSI) models under different wind speeds are analyzed, and the numerical calculation results are compared with those of the centralized mass model. The results show that the tower shadow effect and structural deformation are the main factors affecting the aerodynamic load fluctuation of the wind turbine, which in turn affects the aerodynamic performance and structural stability of the blades. The structural dynamic response of the coupled model shows significant similarity, while the structural displacement response of the former exhibits less fluctuation compared with the conventional centralized mass model. The one-way fluid-structure interaction(FSI)model shows a higher frequency of stress-strain and displacement oscillations on the blade compared with the two-way FSI model.

关键词： computational fluid dynamics methods(CFD) tower shadow effect aerodynamic performance fluidstructure interaction space flow field