检索结果-南通市图书馆

An Energy Stable SPH Method for Incompressible Fluid Flow

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Applied Mathematics and Mechanics 2022年第5期14卷 1201-1224页

作者： Xingyu Zhu Shuyu Sun Jisheng Kou Computational Transport Phenomena Laboratory Division of Physical Science and EngineeringKing Abdullah University of Science and TechnologyThuwal 23955-6900Saudi Arabia School of Civil Engineering Shaoxing UniversityShaoxing 312000ZhejiangChina School of Mathematics and Statistics Hubei Engineering UniversityXiaogan 432000HubeiChina

In this paper,a novel unconditionally energy stable Smoothed Particle Hydrodynamics(SPH)method is proposed and implemented for incompressible fluid flows.In this method,we apply operator splitting to break the momentum equation into equations involving the non-pressure term and pressure term separately.The idea behind the splitting is to simplify the calculation while still maintaining energy stability,and the resulted algorithm,a type of improved pressure correction scheme,is both efficient and energy stable.We show in detail that energy stability is preserved at each full-time step,ensuring unconditionally numerical stability.Numerical examples are presented and compared to the analytical solutions,suggesting that the proposed method has better accuracy and stability.Moreover,we observe that if we are interested in steady-state solutions only,our method has good performance as it can achieve the steady-state solutions rapidly and accurately.

关键词： Particle method Smoothed Particle Hydrodynamics(SPH)method incompressible fluid flow energy stability numerical stability

Review of deep learning algorithms in molecular simulations and perspective applications on petroleum engineering

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Geoscience Frontiers 2024年第2期15卷 55-67页

作者： Jie Liu Tao Zhang Shuyu Sun Physical Science and Engineering Division(PSE) Computational Transport Phenomena LaboratoryKing Abdullah University of Science and Technology(KAUST)Thuwal 23955-6900Saudi Arabia

In the last few decades,deep learning(DL)has afforded solutions to macroscopic problems in petroleum engineering,but mechanistic problems at the microscale have not benefited from it.Mechanism studies have been the strong demands for the emerging projects,such as the gas storage and hydrate production,and for some problems encountered in the storage process,which are common found as the chemical interaction between injected gas and mineral,and the formation of hydrate.Emerging advances in DL technology enable solving molecular dynamics(MD)with quantum accuracy.The conventional quantum chemical method is computational expensive,whereas the classical MD method cannot guarantee high accuracy because of its empirical force field parameters.With the help of the DL force field,precision at the quantum chemistry level can be achieved in MD.Moreover,the DL force field promotes the computational speed compared with first-principles calculations.In this review,the basic knowledge of the molecular force field and deep neural network(DNN)is first introduced.Then,three representative opensource packages relevant to the DL force field are introduced.As the most common components in the development of oil and gas reservoirs,water and methane are studied from the aspects of computational efficiency and chemical reaction respectively,providing the foundation of oil and gas researches.However,in the oil and gas problems,the complex molecular topo structures and various element types set a high challenge for the DL techniques in MD.Regarding the computational efficiency,it needs improvement via GPU and parallel accelerations to compete with classical MD.Even with such difficulties,the booming of this technique in the area of petroleum engineering can be predictable.

关键词： Deep neural network Molecular dynamics Force field Petroleum engineering

STABILITY AND CONVERGENCE ANALYSIS OF SECOND-ORDER SCHEMES FOR A DIFFUSE INTERFACE MODEL WITH PENG-ROBINSON EQUATION OF STATE

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2017年第6期35卷 737-765页

作者： Qiujin Peng Zhonghua Qiao Shuyu Sun Institute for Mathematical Sciences Renmin University of China Beijing 100872 China Department of Applied Mathematics The Hong Kong Polytechnic University Hung Horn Hong Kong Division of Physical Sciences and Engineering King Abdullah University of Science and Technology Thuwal 23955-6900 Kingdom of Saudi Arabia

In this paper, we present two second-order numerical schemes to solve the fourth order parabolic equation derived from a diffuse interface model with Peng-Robinson Equation of state （EOS） for pure substance. The mass conservation, energy decay property, unique solvability and L~ convergence of these two schemes are proved. Numerical results demon- strate the good approximation of the fourth order equation and confirm reliability of these two schemes.

关键词： Diffuse interface model Fourth order parabolic equation Energy stability,Convergence.

Contaminant Flow and Transport Simulation in Cracked Porous Media Using Locally Conservative Schemes

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Applied Mathematics and Mechanics 2012年第4期4卷 389-421页

作者： Pu Song Shuyu Sun Department of Mathematical Sciences Clemson University ClemsonSC 29634USA Computational Transport Phenomena Laboratory(CTPL) Division of Physical Sciences and Enginerring(PSE)King Abdullah University of Science and Technology(KAUST)4700 King Abdullah University of Science and TechnologyThuwal 23955-6900Kingdom of Saudi Abrabia

The purpose of this paper is to analyze some features of contaminant flow passing through cracked porous medium,such as the influence of fracture network on the advection and diffusion of contaminant species,the impact of adsorption on the overall transport of contaminant wastes.In order to precisely describe the whole process,we firstly build the mathematical model to simulate this problem numerically.Taking into consideration of the characteristics of contaminant flow,we employ two partial differential equations to formulate the whole problem.One is flow equation;the other is reactive transport equation.The first equation is used to describe the total flow of contaminant wastes,which is based on Darcy law.The second one will characterize the adsorption,diffusion and convection behavior of contaminant species,which describes most features of contaminant flow we are interested in.After the construction of numerical model,we apply locally conservative and compatible algorithms to solve this mathematical model.Specifically,we apply Mixed Finite Element(MFE)method to the flow equation and Discontinuous Galerkin(DG)method for the transport equation.MFE has a good convergence rate and numerical accuracy for Darcy velocity.DG is more flexible and can be used to deal with irregular meshes,as well as little numerical diffusion.With these two numerical means,we investigate the sensitivity analysis of different features of contaminant flow in our model,such as diffusion,permeability and fracture density.In particular,we study Kd values which represent the distribution of contaminant wastes between the solid and liquid phases.We also make omparisons of two different schemes and discuss the advantages of both methods.

关键词： Mixed finite element methods discontinuous Galerkin methods reactive transport equation flow equation

EFFICIENT LINEAR SCHEMES WITH UNCONDITIONAL ENERGY STABILITY FOR THE PHASE FIELD MODEL OF SOLID-STATE DEWETTING PROBLEMS

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2020年第3期38卷 452-468页

作者： Jie Chen Zhengkang He Shuyu Sun Shimin Guo Zhangxin Chen School of Mathematics and Statistics Xi'an Jiaotong UniversityXi'an 710049China Computational Transport Phenomena Laboratory Division of Physical Science and EngineeringKing Abdullah University of Science and TechnologyThuwal 23955-6900Kingdom of Saudi Arabia School of Mathematics and Statistics Xi'an Jiaotong Universityy Xi'an 710049China Department of Chemical&Petroleum Engineering Schulich School of EngineeringUniversity of Calgary2500 University Drive N.W.CalgaryAlberta T2N 1N4Canada

In this paper,we study linearly first and second order in time,uniquely solvable and unconditionally energy stable numerical schemes to approximate the phase field model of solid-state dewetting problems based on the novel"scalar auxiliary variable"(SAV)approach,a new developed efficient and accurate method for a large class of gradient flows.The schemes are based on the first order Euler method and the second order backward differential formulas(BDF2)for time discretization,and finite element methods for space discretization.The proposed schemes are proved to be unconditionally stable and the discrete equations are uniquely solvable for all time steps.Various numerical experiments are presented to validate the stability and accuracy of the proposed schemes.

关键词： Phase field models Solid-state dewetting SAV Energy stability Surface diffusion Finite element method

Explore the mechanism of pulsed electric field technology on improving the antioxidant activity of Leu-Tyr-Gly-Ala-Leu-Gly-Leu

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Food Bioscience 2022年第3期47卷 289-297页

作者： Liangzi sun Mengqi Li shuyu Zhang Zhijie Bao Songyi Lin National Engineering Research Center of Seafood School of Food Science and TechnologyDalian Polytechnic UniversityDalian116034PR China

In this study,the synthetic peptide Leu-Tyr-Gly-Ala-Leu-Gly-Leu(LYGALGL)derived from egg white was used as the research object.The structure-activity relationship was elucidated by cell experiment and structure determination.The results of cell experiment showed that the superoxide dismutase(SOD)activity and mitochondrial membrane potential(MMP)of LYGALGL were significantly increased by pulsed electric field(PEF)treatment,especially by 10 kV/cm field intensity treatment(P<0.05).However,the content of reactive oxygen species(ROS)decreased significantly(P<0.05).LYGALG treated with 10 kV/cm showed the highest antioxidant activity.The results of structure determination showed that theβ-turn of LYGALGL increased,the random coil decreased,and the active hydrogen sites moved under 10 kV/cm treatment.The structure of LYGALGL was changed and the active site was exposed by PEF,thus improving the antioxidant activity of LYGALGL.

关键词： Pulsed electric field(PEF) Egg white LYGALGL Antioxidant Secondary structure Structure Activity relationship

Cocrystal engineering:towards high-performance near-infrared organic phototransistors based on donor-acceptor charge transfer cocrystals

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Chemistry 2023年第1期66卷 266-272页

作者： Fei Li Lei Zheng Yajing sun shuyu Li Lingjie sun Fangxu Yang Weibing Dong Xiaotao Zhang Wenping Hu Tianjin Key Laboratory of Molecular Optoelectronic Sciences Institute of Molecular Aggregation Science of Tianjin UniversityTianjin 300072China Tianjin Key Laboratory of Molecular Optoelectronic Sciences School of ScienceTianjin UniversityTianjin 300072China Joint School of National University of Singapore and Tianjin University International Campus of Tianjin UniversityFuzhou 350207China Key Laboratory of Resource Chemistry and Eco-environmental Protection in Qinghai-Tibet Plateau Qinghai Minzu UniversityXining 810007China

Near-infrared organic phototransistors have wide application prospects in many fields.The active materials with the high mobility and near-infrared response are critical to building high-performance near-infrared organic phototransistors,which are scarce at present.Herein,a new charge transfer cocrystal using 5,7-dihydroindolo[2,3-b]carbazole(5,7-ICZ)as the donor and 2,2’-(benzo[1,2-b:4,5-b’]dithiophene-4,8-diylidene)dimalononitrile(DTTCNQ)as the acceptor is properly designed and prepared in a stoichiometric ratio(D:A=1:1),which not only displays a high electron mobility of 0.15 cm^(2)V^(-1)s^(-1) and very low dark current,but also can serve as the active layer materials in the region of near-infrared detection due to the narrowed band gap and good charge transport properties.A high photosensitivity of 1.8×10^(4),the ultrahigh photoresponsivity of 2,923 A W-1and the high detectivity of 4.26×10^(11)Jones of the organic near-infrared phototransistors are obtained.

关键词： organic semiconductors charge transporting properties organic cocrystals organic field effect transistors near-infrared organic phototransistors

Mediator complex subunit MED25 physically interacts with DST to regulate spikelet number in rice

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Integrative Plant Biology 2022年第4期64卷 871-883页

作者： Lihao Lin Minmin Du shuyu Li Chuanlong sun Fangming Wu Lei Deng Qian Chen Chuanyou Li State Key Laboratory of Plant Genomics National Centre for Plant Gene Research(Beijing)Institute of Genetics and Developmental BiologyThe Innovative Academy of Seed DesignThe Chinese Academy of SciencesBeijing 100101China State Key Laboratory of Crop Biology College of AgronomyShandong Agricultural UniversityTaian 271018China

Grain number is a flexible trait and contributes significantly to grain yield.In rice,the zinc finger transcription factor DROUGHT AND SALT TOLERANCE(DST)controls grain number by directly regulating cytokinin oxidase!dehydrogenase 2(OsCKX2)expression.Although specific upstream regulators of the DST-OsCKX2 module have been identified,the mechanism employed by DST to regulate the expression of OsCKX2 remains unclear.Here,we demonstrate that DST-interacting protein 1(DIP1),known as Mediator subunit OsMED25,acts as an interacting coactivator of DST.Phenotypic analyses revealed that OsMED25-RNAi and the osmed25 mutant plants exhibited enlarged panicles,with enhanced branching and spikelet number,similar to the dst mutant.Genetic analysis indicated that OsMED25 acts in the same pathway as the DST-OsCKX2 module to regulate spikelet number per panicle.Further biochemical analysis showed that OsMED25 physically interacts with DST at the promoter region of OsCKX2,and then recruits RNA polymerase II(Pol II)to activate OsCKX2 transcription.Thus,OsMED25 was involved in the communication between DST and Pol II general transcriptional machinery to regulate spikelet number.In general,our findings reveal a novel function of OsMED25 in DST-OsCKX2 modulated transcriptional regulation,thus enhancing our un derstanding of the regulatory mechanism underlying DST-OsCKX2-mediated spikelet number.

关键词： DST MED25 OsCKX2 rice spikelet number

On Stochastic Error and Computational Efficiency of the Markov Chain Monte Carlo Method

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Communications in Computational Physics 2014年第7期16卷 467-490页

作者： Jun Li Philippe Vignal Shuyu Sun Victor M.Calo Center for Numerical Porous Media King Abdullah University of Science and TechnologyThuwalSaudi Arabia Material Science and Engineering King Abdullah University of Science and TechnologyThuwalSaudi Arabia AppliedMathematics and Computational Science Earth Sciences and EngineeringKing Abdullah University of Science and TechnologyThuwalSaudi Arabia.

InMarkov ChainMonte Carlo(MCMC)simulations,thermal equilibria quantities are estimated by ensemble average over a sample set containing a large number of correlated samples.These samples are selected in accordance with the probability distribution function,known from the partition function of equilibrium state.As the stochastic error of the simulation results is significant,it is desirable to understand the variance of the estimation by ensemble average,which depends on the sample size(i.e.,the total number of samples in the set)and the sampling interval(i.e.,cycle number between two consecutive samples).Although large sample sizes reduce the variance,they increase the computational cost of the simulation.For a given CPU time,the sample size can be reduced greatly by increasing the sampling interval,while having the corresponding increase in variance be negligible if the original sampling interval is very small.In this work,we report a few general rules that relate the variance with the sample size and the sampling interval.These results are observed and confirmed numerically.These variance rules are derived for theMCMCmethod but are also valid for the correlated samples obtained using other Monte Carlo methods.The main contribution of this work includes the theoretical proof of these numerical observations and the set of assumptions that lead to them.

关键词： Phase coexistence Gibbs ensemble molecular simulation Markov Chain Monte Carlo method variance estimation blocking method