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Gradient Estimates for p-Laplacian Lichnerowicz Equation on Noncompact Metric Measure Space

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Chinese Annals of Mathematics,Series B 2020年第3期41卷 397-406页

作者： Liang ZHAO ming shen Department of Mathematics Nanjing University of Aeronautics and AstronauticsNanjing 210016China College of Mathematics and Computer Science Fuzhou UniversityFuzhou 350116China

In this paper, the authors obtain the gradient estimates for positive solutions to the weighted p-Laplacian Lichnerowicz equation △p,fu + cuσ= 0 on noncompact smooth metric measure space, where c is a nonnegative constant, and p, σ(1 < p≤2, σ≤p-1) are real constants. Moreover, by the gradient estimate, they can get the corresponding Liouville theorem and Harnack inequality.

关键词： p-Laplacian Positive solutions Liouville theorem

Determination of water flushing characteristics and their influencing factors on the Dahuofang Reservoir in China using an improved ECOMSED model

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Frontiers of Earth Science 2015年第3期9卷 394-411页

作者： ming ZHANG Yongming shen State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116023 China

A three-dimensional hydrodynamic model with the capability to deal with changing land water boundaries was developed based on ECOMSED in this study. The model was configured to numerically study the water flushing characteristics of Dahuofang Reservoir in China through the determination of spatially distributed residence times. The model successfully reproduced the intra-annual water level variations, as well as the temporal evolution and spatial distribution of water temperature. Through a series of numerical experiments, it can be concluded that （1） the water flushing of the reservoir is both temporally and spatially variable; and （2） inflows and withdrawals are the decisive factors influencing the water flushing characteristics. Heat fluxes are the controlling factors of the water flushing of a strong stratified reservoir. Wind has the weakest effect, but it still should be considered in determination of reservoir water flushing characteristics.

关键词： numerical modeling residence time flushing,influence factor Dahuofang Reservoir

Combined grain size, strain rate and loading condition effects on mechanical behavior of nanocrystalline Cu under high strain rates

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Acta Mechanica Sinica 2012年第4期28卷 1125-1132页

作者： Lu-ming shen School of Civil Engineering The University of SydneyNSW 2006 Australia

Molecular dynamics simulations of nanocrystalline Cu with average grain sizes of 3.1 nm, 6.2 nm, 12.4 nm and 18.6 nm under uniaxial strain and stress tension at strain rates of 10^8 s^-1, 10^9 S^-1 and 10^10 s^-1 are performed to study the combined grain size, strain rate and loading condition effects on mechanical properties. It is found that the strength of nanocrystalline Cu increases as grain size increases regardless of loading condition. Both the strength and ductility of nanocrystalline Cu increase with strain rate except that there is no monotonic relation between the strength and strain rate for specimens under uni- axial strain loading. Moreover, the strength and ductility of specimens under uniaxial strain loading are lower than those under uniaxial stress loading. The nucleation of voids at grain boundaries and their subsequent growth characterize the failure of specimens under uniaxial strain loading, while grain boundary sliding and necking dominate the failure of specimens under uniaxial stress loading. The rate dependent strength is mainly caused by the dynamic wave effect that limits dislocation motion, while combined twinning and slipping mechanism makes the material more ductile at higher strain rates.

关键词： Nanocrystalline Grain boundaries . Grain size stress . Uniaxial strain Cu. Molecular dynamics . High strain rates. Uniaxial

STUDY AND APPLICATION OF STEADY FLOW AND UNSTEADY FLOW MATHEMATICAL MODEL FOR CHANNEL NETWORKS

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Journal of Hydrodynamics 2007年第5期19卷 572-578页

作者： ZHANG ming-liang shen Yong-ming State Key Laboratory of Coastal and Offshore Engineering Dalian University of Technology Dalian 116024 China

Based on the Preissmann implicit scheme for the one-dimensional Saint-Venant equation, the mathematical model for one-dimensional fiver networks and canal networks was developed and the key issues on the model were expatiated particularly in this article. This model applies the method of three-steps solution for chaunel-junction-channel to simulate the river networks, and the Gauss elimination method was used to calculate the sparse matrix. This model was applied to simulate the tree-type irrigation canal networks, complex looped channel networks and the Lower Columbia Slough networks. The results of water level and discharge agree with the data from the Adlul and field data. The model is proved to be robust for simulating unsteady flows in river networks with various degrees of complex structure. The calculated results show that this model is useful for engineering applications in complicated river networks. Future research was recommended to focus on setting up ecological numerical model of water quality in river networks and canal networks.

关键词： Preissmann implicit scheme canal networks and river networks unsteady flow ecological numerical model

Simulation and Analysis of Dual-Evaporator Refrigeration System for Electric Vehicles

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Automotive Innovation 2020年第4期3卷 347-355页

作者： ming shen Qing Gao State Key Laboratory of Automotive Simulation and Control Jilin UniversityChangchun 130025China College of Automotive Engineering Jilin UniversityChangchun 130025China Department of Thermal Engineering Jilin UniveristyChangchun 130022China

Thermal management system is a crucial part in electric vehicles to ensure battery safety and driving comfort.A refrigerant-based thermal management system of electric vehicles with two evaporators connected in series(series system)or in parallel(parallel system)is *** performances of the two systems are investigated and *** results reveal that the optimal refrigerant charge is approximately 600 ***,there is no correlation between the optimal refrigerant charge,and in the arrangement of heat sinks or the heat *** the optimal refrigerant charge,the coefficient of perfor-mance of the series system ranges from 3.47 to *** coefficient of performance of the parallel system ranges from 3.40 to 4.59,which is lower than that of the series ***,the series system has higher exergy efficiency and better cooling *** heat source(cabin)with a small thermal mass placed in the rear evaporator of the series system can weaken the lag of its cooling *** additional serial evaporator is an alternative solution to the dual-evaporator thermal management system of electric vehicles.

关键词： Lithium-ion battery Thermal management Dual evaporators Simulation analysis

A Kinematical Calibration of the Galactocentric Distance

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Chinese Journal of Astronomy and Astrophysics 2007年第1期7卷 120-128页

作者： ming shen Zi Zhu Department of Astronomy Nanjing University Nanjing 210093

We present a new determination of the Galactocentric distance by a pure kinematical model. Two subgroups of components from the Galactic thin disk, the O-B5 stars and the Galactic open clusters, were selected for our analysis. On the basis of kinematical data of around 1200 O-B5 stars, we obtained an estimated value of Ro=8.25-4-0.79 kpc, while a similar evaluation from 270 Galactic open clusters gives Ro=7.95-4-0.62 kpc. Considering the scatter of Ro given by individual investigators with different methods, our present determinations agree well with the best value proposed by Reid.

关键词： Galaxy kinematics and dynamics-stars early-type-open clusters and associations

An Efficient Approach of Processing Multiple Continuous Queries

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Journal of Computer Science & Technology 2016年第6期31卷 1212-1227页

作者： Wen Liu Yan-ming shen Peng Wang School of Computer Science and Technology Dalian University of Technology Dalian 116024 China School of Computer Science Fudan University Shanghai 201203 China

As stream data is being more frequently collected and analyzed, stream processing systems are faced with more design challenges. One challenge is to perform continuous window aggregation, which involves intensive computation. When there are a large number of aggregation queries, the system may suffer from scalability problems. The queries are usually similar and only differ in window specifications. In this paper, we propose collaborative aggregation which promotes aggregate sharing among the windows so that repeated aggregate operations can be avoided. Different from the previous approaches in which the aggregate sharing is restricted by the window pace, we generalize the aggregation over multiple values as a series of reductions. Therefore, the results generated by each reduction step can be shared. The sharing process is formalized in the feed semantics and we present the compose-and-declare framework to determine the data sharing logic at a very low cost. Experimental results show that our approach offers an order of magnitude performance improvement to the state-of-the-art results and has a small memory footprint.

关键词： data stream streams aggregation query sharing continuous query

Thermal conductivity model of filled polymer composites

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International Journal of Minerals,Metallurgy and Materials 2011年第5期18卷 623-631页

作者： ming-xia shen Yin-xin Cui Jing He Yao-ming Zhang College of Mechanics and Materials Hohai University Nanjing 210098 China

Theoretical and empirical models for predicting the thermal conductivity of polymer composites were summarized since the *** effects of particle shape,filler amount,dispersion state of fillers,and interfacial thermal barrier on the thermal conductivity of filled polymer composites were investigated,and the agreement of experimental data with theoretical models in literatures was *** with high thermal conductivity was chosen to mix with polyvinyl-acetate （EVA） copolymer to prepare SiO2/EVA *** data of the co-films＇ thermal conductivity were compared with some classical theoretical and empirical *** results show that Agari＇s model,the mixed model,and the percolation model can predict well the thermal conductivity of SiO2/EVA co-films.

关键词： polymer matrix composites thermal conductivity mathematical models polyvinyl acetates silica filled polymers.

Development of chromatographic technologies for the quality control of Traditional Chinese Medicine in the Chinese Pharmacopoeia

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Journal of Pharmaceutical Analysis 2021年第2期11卷 155-162页

作者： ming-Rui shen Yi He Shang-Mei Shi Chinese Pharmacopoeia Commission No.11 Fahua NanliBeijing100061China

As an important branch of medicine, Traditional Chinese Medicine(TCM) has been applied for the treatment of diseases for thousands of years in China and other countries in East Asia. The Chinese Pharmacopoeia(ChP) is a drug code formulated by the Chinese government, and it includes a special volume for the monographs of TCM, which plays an important role in ensuring the quality of drugs. The use of quality control technology has always been a complex and important factor in TCM. Owing to the chemical diversity of TCM, chromatography technology has been proven to be a comprehensive strategy for the assessment of the overall quality of TCM and has become the main analytical method in the *** article provides an overview of the classical and modern chromatographic technologies applied in the ChP, and summarizes the advantages and disadvantages of each technique in the TCM *** 2020, the new edition of the Ch P(the 2020 edition) has been implemented at the end of 2020. This paper also contains a brief introduction about the application of chromatographic technologies in the new edition of the ChP.

关键词： Traditional Chinese medicine Chinese pharmacopoeia Chromatographic technology Quality control