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A Generalization of Vosper's Theorem

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Chinese Annals of Mathematics,Series B 2024年第5期45卷 767-776页

作者： yujie wang Min TANG School of Mathematics and Statistics Anhui Normal UniversityWuhu 241002AnhuiChina

Let Z/m Z be the ring of residual classes modulo m,and let A and B be nonempty subsets of Z/m *** this paper,the authors give the structure of A and B for which|A+B|=|A|+|B|-1=m-2.

关键词： Sumsets Inverse problem Vosper's theorem Kemperman's theorem

Impacts of 1.5℃ and 2.0℃ Global Warming on Runoff of Three Inland Rivers in the Hexi Corridor, Northwest China

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Journal of Meteorological Research 2020年第5期34卷 1082-1095页

作者： yujie wang Yong wang Hongmei XU Key Laboratory of Meteorological Disaster Ministry of Education/International Joint Research Laboratory on Climate and Environment Change/Collaborative Innovation Center on Forecast and Evaluation of Meteorological DisastersNanjing University of Information Science&TechnologyNanjing 210044 School of Atmospheric Sciences Nanjing University of Information Science&TechnologyNanjing 210044 Chongqing Climate Center Chongqing Meteorological ServiceChongqing 401147 National Climate Center China Meteorological AdministrationBeijing 100081

Basin-scale projections of river runoff at different warming levels provide useful information for climate change adaptation. In this study, we investigated changes in the projected climate and simulated runoff under 1.5℃ and 2.0℃ global warming of three inland rivers in the Hexi Corridor: the Shiyang River(SYR), the Heihe River(HHR),and the Shule River(SLR). The change in climate was projected based on five global climate models(GCMs) under three representative concentration pathways(RCPs), and the change in runoff was simulated based on the Soil and Water Assessment Tool(SWAT) hydrological model. Furthermore, the uncertainties in projected climate change and simulated runoff constrained by the GCMs and RCPs were quantified. The results indicate that, compared with the baseline period(1976–2005), there is a 1.42–1.54℃ increase in annual air temperature and 4%–12% increase in annual mean precipitation in the three river basins under 1.5℃ global warming, while there is a 2.09–2.36℃ increase in annual air temperature and 5%–11% increase in annual mean precipitation under 2.0℃ global warming. The simulated annual runoff of the SYR decreases by 4% under 1.5℃ global warming, that of the HHR decreases by 3% and 4%, while that of the SLR increases considerably by 10% and 11% under 1.5℃ and 2.0℃ global warming, respectively. The additional 0.5℃ global warming results in an annual air temperature increase of 0.67–0.82℃, a change of -1% to 1% in annual mean precipitation, and a change of -1% to 5% in simulated runoff. The simulated annual runoff has greater uncertainty. The simulations indicate substantial and consistent warming in autumn and winter in the three basins, relatively drier summer and autumn in the SYR and HHR basins, and a relatively drier autumn in the SLR basin. The simulated monthly runoff shows more complex changes with large uncertainties constrained mainly by the GCMs.

关键词： climate change runoff Shiyang River(SYR) Heihe River(HHR) Shule River(SLR)

A compact 3D block cutting and contact searching algorithm

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Science China(Technological Sciences) 2019年第8期62卷 1438-1454页

作者： LIN XingChao LI Xu wang XiaoGang wang yujie State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin Beijing 10003& China Key Laboratory of Urban Underground Engineering of Ministry of Education Beijing Jiaotong University Beijing 100044 China Department of Geotechnical Engineering China Institute of Water Resources and Hydropower Research Beijing 100048 China

The geometry relation and the contact point-pairs detection between two three dimensional(3D) objects with arbitrary shapes are essential problems involved in discontinuous computation and computational geometry. This paper reported a geometry relation judgment and contact searching algorithm based on Contact Theory. A contact cover search algorithm is proposed to find all the possible contact cover between two blocks. Two blocks can come to contact only on these covers. Each contact cover can define a possible contact point-pair between two blocks. Data structure and flow chart are provided, as well as some examples in *** problems involving concave blocks or parallel planes are considered to be very difficult in past and are solved by this algorithm. The proposed algorithm is compacted and applicable to the discontinuous computation, such as robotic control, rock mass stability, dam stability etc. A 3D cutting and block searching algorithm is also proposed in this study and used to search the outer boundary of the 3D entrance block when 3D concave blocks are encountered. The 3D cutting and block searching algorithm can be also used to form the block system for jointed rock.

关键词： contact discontinuous computation block cutting computational geometry jointed rock cover

Separation of Th^(4+) and RE^(3+) with Hollow Fiber Extraction

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Journal of Rare Earths 1999年第2期17卷 9-13页

作者： wang, yujie Zhang, Shumin Li, Deqian Inst of Applied Chemistry Chinese Acad of Sciences Changchun China

Separation of Th4+ and RE3+ was investigated by hollow fiber membrane extraction with N1923 in countercurrent recirculating operation. The effect of H+ concentration in aqueous phase and flow rates of aqueous and organic phases on mass transfer coefficient was tested. Then the extraction of Th4+ from RE sulfate obtained from Baotou ore was carried out. The results obtained show that the mass transfer coefficient of Th4+ changes with the flow rate of aqueous phase, but does not change with the flow rate of organic phase and H+ concentration in aqueous phase, which suggests that the mass transfer rate of Th4+ is controlled by that in the water critical layer. The mass transfer rate of RE3+ does not change with the flow rate of water phase, changes a little with the flow rate of organic phase, and changes with H+ concentration, which suggests that the mass transfer rate is controlled by their reaction rate with N1923. Th4+ could be extracted completely in 8 h from RE sulfate solution of Baotou ore withrelatively less extraction of RE3+. So the separation of radioactive element under the sealed condition could be done.

关键词： Rare earths Thorium Hollow fiber membrane Extraction Amine N1923

GLOBAL DYNAMICS OF A CHOLERA MODEL WITH TIME DELAY

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International Journal of Biomathematics 2013年第1期6卷 143-160页

作者： yujie wang JUNJIE WEI Department of Mathematics Harbin Institute of Technology Harbin 150001 Heilongjiang P. R. China Department of Mathematics Jilin Normal University Siping 136000 Jilin P. R. China

The global dynamics of a cholera model with delay is considered. We determine a basic reproduction number R0 which is chosen based on the relative ODE model, and establish that the global dynamics are determined by the threshold value R0. If R0 〈 1, then the infection-free equilibrium is global asymptotically stable, that is, the cholera dies out; If R0 〉 1, then the unique endemic equilibrium is global asymptotically stable, which means that the infection persists. The results obtained show that the delay does not lead to periodic oscillations. Finally, some numerical simulations support our theoretical results.

关键词： Cholera model delay Lyapunov functional global stability.

Battery Full Life Cycle Management and Health Prognosis Based on Cloud Service and Broad Learning

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IEEE/CAA Journal of Automatica Sinica 2022年第8期9卷 1540-1542页

作者： yujie wang Kaiquan Li Zonghai Chen Department of Automation University of Science and Technology of ChinaHefei 230027China

Dear editor,This letter presents battery full life cycle management and health prognosis based on cloud service and broad ***,a cloud-based framework for battery full life cycle management is ***,the broad learning me... 详细信息

关键词： battery Battery prediction.

A PDE Approach to the Long-Time Asymptotic Solutions of Contact Hamilton-Jacobi Equations

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Wuhan University Journal of Natural Sciences 2022年第3期27卷 189-194页

作者： wang yujie LI Xia School of Mathematics Science Suzhou University of Science and TechnologySuzhou 215009JiangsuChina

We study the long-time asymptotic behaviour of viscosity solutions u(x,t)of the Hamilton-Jacobi equation u_(t)(x,t)+H(x,u(x,t),Du(x,t))=0 in T^(n)×(0,∞)with a PDE approach,where H=H(x,u,p)is coercive in p,non-decreasing in u and strictly convex in(u,p),and establish the uniform convergence of u(x,t)to an asymptotic solution u_(∞)(x)as t→∞.Moreover,u_(∞) is a viscosity solution of Hamilton-Jacobi equation H(x,u(x),Du(x))=0.

关键词： asymptotic solution Hamilton-Jacobi equation PDE approach

Reactor characterization and primary application of a state of art dual-reactor chamber in the investigation of atmospheric photochemical processes

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Journal of Environmental Sciences 2020年第12期32卷 161-168页

作者： Hao Luo Guiying Li Jiangyao Chen yujie wang Taicheng An Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control Guangzhou Key Laboratory Environmental Catalysis and Pollution ControlSchool of Environmental Science and EngineeringInstitute of Environmental Health and Pollution ControlGuangdong University of TechnologyGuangzhou 510006China

Increasing attention has been paid to the air pollution more recently. Smog chamber has been proved as a necessary and effective tool to study atmospheric processes, including photochemical smog and haze formation. A novel smog chamber was designed to study the atmospheric photochemical reaction mechanism of typical volatile organic compounds(VOCs) as well as the aging of aerosols. The smog chamber system includes an enclosure equipped with black lights as the light source, two parallel reactors(2 m^3 of each) with separate control of light source and temperature, with a series of coupled instruments for online monitoring of gas phase and particle phase reactants and products. Chamber characterization, including air source stability, effective light intensity, temperature stability, as well as gas phase and particle phase wall losses, were carried out before further research. The results showed that our smog chamber systems developed by other domestic and international groups. It was also observed that the wall loss of aromatic VOCs varied with different functional groups as well as the isomerism. The results of preliminary simulation experiment from styrene-NO_x demonstrated that the chamber can be well utilized to simulate gas-particle conversion progresses in the atmosphere.

关键词： Smog chamber Dual-reactors Volatile organic compounds Ozone formation Secondary organic aerosol

A survey of Digital Twin techniques in smart manufacturing and management of energy applications

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Green Energy and Intelligent Transportation 2022年第2期1卷 51-61页

作者： yujie wang Xu Kang Zonghai Chen Department of Automation University of Science and Technology of ChinaHefeiAnhui230027China

With the continuous advancement and exploration of science and technology,the future trend of energy technology will be the deep integration of digitization,networking,intelligence with energy *** increasing maturity of digital technologies,such as the Internet of Things,big data,and cloud computing,has given rise to the creation and use of a potential technology–Digital ***,research on Digital Twin has produced many concepts and outcomes that have been applied in many *** the energy sector,while some relevant ideas and case studies of Digital Twin have been generated,there are still many gaps to be *** a potential technology with advantages in many aspects,Digital Twin is bound to generate more promotion and applications in the energy *** paper systematically reviews the existing Digital Twin approaches and their possible applications in the energy *** addition,this paper attempts to analyze Digital Twin from different perspectives,such as definitions,classifications,main features,case studies and key ***,the directions and challenges of possible future applications of Digital Twin in the energy fields have been presented.

关键词： Digital Twin Smart energy application Low carbon city Smart grid Electrified transportation Energy storage system