检索结果-南通市图书馆

On the Numerical Solution to a Nonlinear Wave Equation Associated with the First Painlev Equation:an Operator-Splitting Approach

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of mathematics,Series B 2013年第2期34卷 237-254页

作者： Roland GLOWINSKI Annalisa QUAINI department of mathematics University of Houston4800 Calhoun RdHouston(TX) 77204USA laboratoire Jacques-Louis Lions Universit Pierre et Marie Curie4Place Jussieu75252 Paris CEDEX 05France

The main goal of this article is to discuss the numerical solution to a nonlinear wave equation associated with the first of the celebrated Painlev'e transcendent ordinary differential *** order to solve numerically the above equation,whose solutions blow up in finite time,the authors advocate a numerical methodology based on the Strang's symmetrized operator-splitting *** this approach,one can decouple nonlinearity and differential operators,leading to the alternate solution at every time step of the equation as follows:(i) The first Painlevé ordinary differential equation,(ii) a linear wave equation with a constant *** that the space dimension is two,the authors consider a fully discrete variant of the above scheme,where the space-time discretization of the linear wave equation sub-steps is achieved via a Galerkin/finite element space approximation combined with a second order accurate centered time discretization *** handle the nonlinear sub-steps,a second order accurate centered explicit time discretization scheme with adaptively variable time step is used,in order to follow accurately the fast dynamic of the solution before it blows *** results of numerical experiments are presented for different coefficients and boundary *** show that the above methodology is robust and describes fairly accurately the evolution of a rather "violent" phenomenon.

关键词：非线性波动方程 Painlevé方程数值解法操作员 Galerkin 常微分方程分裂分离方法

Pattern dynamics of a reaction-diffusion predator-prey system with both refuge and harvesting

在线全文

学校读者我要写书评

暂无评论

International Journal of Biomathematics 2021年第1期14卷 1-29页

作者： Lakshmi Narayan Guin Sudipta Pal Santabrata Chakravarty Salih Djilali department of mathematics Visva-BharatiSantiniketan 731235West BengalIndia department of mathematics Universite Hassiba Benbouali de ChlefChlef 02000Algeria Laboratoire d’Analyse Non Linéaire et Mathématiques AppliquéesUniversitéde TlemcenTlemcenAlgeria

We are concerned with a reaction-diffusion predator–prey model under homogeneous Neumann boundary condition incorporating prey refuge(proportion of both the species)and harvesting of prey species in this *** for asymptotic stability(local and global)and bifurcation of the subsequent temporal model system are thoroughly analyzed around the unique positive interior equilibrium *** partial differential equation(PDE),the conditions of diffusion-driven instability and the Turing bifurcation region in two-parameter space are *** results around the unique interior feasible equilibrium point specify that the effect of refuge and harvesting cooperation is an important part of the control of spatial pattern formation of the species.A series of computer simulations reveal that the typical dynamics of population density variation are the formation of isolated groups within the Turing space,that is,spots,stripe-spot mixtures,labyrinthine,holes,stripe-hole mixtures and stripes ***,we discuss spatiotemporal dynamics of the system for a number of different momentous parameters via numerical simulations.

关键词： Two species reaction-diffusion system ratio-dependent functional response diffusion-driven instability pattern selection stationary patterns

Preface for Cyber‑Attack Detection and Resilient Control of Intelligent and Connected Vehicles

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Automotive Innovation 2023年第2期6卷 143-145页

作者： Hui Zhang Manjiang Hu Anh‑Tu Nguyen Yunpeng Wang Yang Shi School of Transportation Science and Engineering Beihang UniversityBeijingChina College of Mechanical and Vehicle Engineering Hunan UniversityChangshaChina laboratoire d’Automatique de Mécanique et d’Informatique Industrielles et Humaines UMR CNRS 8201UniversitéPolytechnique des Hauts-de-FranceValenciennesFrance department of Mechanical Engineering University of VictoriaVictoriaBCCanada

Intelligent and connected vehicles(ICVs),as a critical future product of the automotive industry,have developed rapidly in recent *** insertion of a cyber chain between vehicles can bring considerable benefits,including shared perception information,improved traffic efficiency,enhanced vehicle safety,optimized energy utilization,and reduced carbon emissions.

关键词： insertion Preface benefits

Physiological Responses of Pea Plants to Salinity and Gibberellic Acid

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Phyton-International Journal of Experimental Botany 2023年第1期92卷 149-164页

作者： Houneida Attia department of Biology College of ScienceTaif UniversityTaif21944Saudi Arabia laboratoire ProductivitéVégétale et Contraintes Environnementales Département des Sciences BiologiquesFacultédes Sciences de TunisUniversitéTunis El ManarTunis2092Tunisia

Pea is a seed *** is rich in cellulose fibre and *** is also a significant source of minerals and *** this paper,we set out to better characterize the physiological responses of Pisum sativum *** the combined effects of NaCl,100 mM and gibberellins(GA3).Our analysis revealed that NaCl caused a decrease in growth resulting in a reduction in root elongation,distribution and density,leaf number and leaf area,and a decrease in dry matter of roots and ***,the contribution of GA3 in the salty environment induced an increase in these different parameters suggesting an improving effect of this hormone on growth of pea in presence of *** also led to a disturbance of the photosynthetic ***,level of chlorophyll pigments(a and total)and photosynthetic activity were decreased compared to the control ***,the exogenous supply of GA3 restored this decrease in net CO_(2) assimilation,but not in chlorophyll *** analyses were performed on the effect of salinity/GA3 interaction on osmolytes(soluble sugars and starch).Our results showed an increase in sugars and a decrease in starch in the presence of 100 mM *** salt-GA3 combination resulted in compensation of soluble sugar contents but not of starch contents,suggesting a beneficial effect of GA3 under saline stress *** of three main polyamines putrescine,spermidine,and spermine increased significantly in all organs of salt-treated plants.

关键词： Pisum sativum L. salinity gibberellic acid growth sugars polyamines

Enhanced Learning Resource Recommendation Based on Online Learning Style Model

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2020年第3期25卷 348-356页

作者： Hui Chen Chuantao Yin Rumei Li Wenge Rong Zhang Xiong Bertrand David the School of Computer Science and Engineering Beihang UniversityBeijing 100191China Sino-French Engineer School Beihang UniversityBeijing 100191China. laboratoire cHnfoRmatique en Image et systemes d*information(LIRIS)Lab Ecole Centrale de LyonEcully69134France

Smart learning systems provide relevant learning resources as a personalized bespoke package for learners based on their pedagogical needs and individual *** paper introduces a learning style model to represent features of online *** also presents an enhanced recommendation method named Adaptive Recommendation based on Online Learning Style(AROLS),which implements learning resource adaptation by mining learners’behavioral ***,AROLS creates learner clusters according to their online learning ***,it applies Collaborative Filtering(CF)and association rule mining to extract the preferences and behavioral patterns of each ***,it generates a personalized recommendation set of variable size.A real-world dataset is employed for some *** show that our online learning style model is conducive to the learners’data mining,and AROLS evidently outperforms the traditional CF method.

关键词： smart learning e-learning online learning style adaptive recommendation Collaborative Filtering(CF)

Overall Assessment of Heat Transfer for a Rarefied Flow in a Microchannel with Obstacles Using Lattice Boltzmann Method

在线全文

学校读者我要写书评

暂无评论

工程与科学中的计算机建模(英文) 2024年第1期138卷 273-299页

作者： Siham Hammid Khatir Naima Omolayo M.Ikumapayi Cheikh Kezrane Abdelkrim Liazid Jihad Asad Mokdad Hayawi Rahman Farhan Lafta Rashid Naseer Ali Hussien Younes Menni Laboratory of Development in Mechanics and Materials(LDMM) Zian Achour UniversityDjelfaPB 3117Algeria department of Technology University Center Salhi Ahmed Naama(Ctr.Univ.Naama)P.O.Box 66Naama45000Algeria department of Mechanical and Mechatronics Engineering Afe Babalola University Ado Ekiti360101Nigeria Departement of Physics Faculty of ScienceAbou Bekr Belkaid UniversityTlemcen13000Algeria department of Physics Faculty of Applied SciencesPalestine Technical University-KadoorieTulkarmPalestine Aeronautical Technical Engineering Al-Farahidi UniversityBaghdad10011Iraq Mechanical Engineering department University of KerbalaKarbala56001Iraq Information and Communication Technology Research Group Scientific Research CenterAl-Ayen UniversityThi-QarIraq National University of Science and Technology Dhi QarIraq

The objective of this investigation is to assess the effect of obstacles on numerical heat transfer and fluid flow momentum in a rectangular microchannel(MC).Two distinct configurations were studied:one without obstacles and the other with alternating obstacles placed on the upper and lower *** research utilized the thermal lattice Boltzmann method(LBM),which solves the energy and momentum equations of fluids with the BGK approximation,implemented in a Python coding *** jump and slip velocity conditions were utilized in the simulation for the MC and extended to all obstacle *** study aims to analyze the rarefaction effect,with Knudsen numbers(Kn)of 0.012,0.02,and *** outcomes indicate that rarefaction has a significant impact on the velocity and temperature *** presence of nine obstacles led to slower fluid movement inside the microchannel MC,resulting in faster cooling at the *** MCs with obstacles,the rarefaction effect plays a crucial role in decreasing the Nusselt number(Nu)and skin friction coefficient(Cf).Furthermore,the study demonstrated that the obstacles played a crucial role in boosting fluid flow and heat transfer in the *** findings suggest that the examined configurations could have potential applications as cooling technologies in micro-electro-mechanical systems and microdevice applications.

关键词： Microfluid rarefied flow LBM microchannel Knudsen number numerical simulation

Pressure-broadened atomic Li(2s-2p) line perturbed by ground neon atoms in the spectral wings and core

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2017年第7期26卷 67-74页

作者： Sabri Bouchoucha Kamel Alioua Moncef Bouledroua Physics department Badji Mokhtar University laboratoire de Physique de la Matière et du Rayonnement Chérif Messaidia University laboratoire de Physique des Rayonnements Badji Mokhtar University

Full quantum calculations are performed to investigate the broadening profiles of the atomic lithium Li（2s-2p） resonance line induced by interactions with ground Ne（2s^22p^6） perturbers in the spectral wings and core. The X^2Σ~＋, A^2Π,and B^2Σ~＋ potential-energy curves of the two first low lying Li Ne molecular states, as well as the corresponding transition dipole moments, are determined with ab initio methods based on the SA-CASSCF-MRCI calculations. The emission and absorption coefficients in the wavelength range 550-800 nm and the line-core width and shift are investigated theoretically for temperatures ranging from 130 K to 3000 K. Their temperature dependence is analyzed, and the obtained results are compared with the previous experimental measurements and theoretical works.

关键词： pressure broadening emission and absorption coefficients linewidth lineshift

Effect of the synthesis route on the structural and dielectric properties of SrBi1.8Y0.2Nb2O9 ceramics

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2018年第11期25卷 1304-1312页

作者： Mohamed Afqir Amina Tachafine Didier Fasquelle Mohamed Elaatmani Jean-Claude Carru Abdelouahad Zegzouti Mustapha El Hammioui laboratoire des Sciences des Matériaux Inorganiques et leurs applications Facultédes Sciences SemlaliaUniversitéCadi AyyadMarrakech 40000Maroc Unite de Dynamique et Structure des Materiaux Moleculaires Universite du Littoral-Cote d’OpaleCalais 62100France laboratoire de recherche sur la réactivitédes matériaux et l’optimisation des procédés Facultédes Sciences SemlaliaUniversitéCadi Ayyad 40000MarrakechMaroc

This work is devoted to the synthesis and characterization of yttrium-doped SrBi_2Nb_2O_9 ceramics prepared by three methods: solid state reaction, co-precipitation, and hydrothermal. Multiple characterizations, specifically scanning electron microscopy(SEM), X-ray powder diffraction(XRD), and Fourier transform infrared spectroscopy(FTIR), were used to validate the structural feature. The crystallite size was estimated by Scherrer's formula and the Williamson–Hall plot. The effect of the process on the band intensities of the FTIR spectra was investigated. The crystallite size and microstructure of ceramics prepared from different synthesis processes were strongly influenced by the sinterability. SEM images revealed nanograin ceramics for materials prepared by co-precipitation and hydrothermal methods and micrograin ceramics prepared by the solid state method. The synthesized compounds underwent phase transitions at 480–465°C. The dielectric and electrical properties of these Y-doped SrBi_2Nb_2O_9 ceramics appear to be dependent on the grain size.

关键词： Aurivillius,synthesis routes crystallite size microstructure dielectric

An Immersed Method Based on Cut-Cells for the Simulation of 2D Incompressible Fluid Flows Past Solid Structures

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2019年第4期119卷 165-184页

作者： Francois Bouchon Thierry Dubois Nicolas James Université Clermont Auvergne CNRSLMBPF-63000 CLERMONT-FERRANDFrance laboratoire de Mathématiques et applications UMR 7348 Universitéde PoitiersTéléport 2-B.P.30179Boulevard Marie et Pierre Curie86962 Futuroscope Chasseneuil CedexFrance

We present a cut-cell method for the simulation of 2D incompressible flows past *** consists in using the MAC scheme on cartesian grids and imposing Dirchlet boundary conditions for the velocity field on the boundary of solid structures following the Shortley-Weller *** order to ensure local conservation properties,viscous and convecting terms are discretized in a finite volume *** scheme is second order implicit in time for the linear part,the linear systems are solved by the use of the capacitance matrix method for non-moving *** results of flows around an impulsively started circular cylinder are presented which confirm the efficiency of the method,for Reynolds numbers 1000 and *** example of flows around a moving rigid body at Reynolds number 800 is also shown,a solver using the PetSc-Library has been prefered in this context to solve the linear systems.

关键词： Immersed boundary methods cutt-cell methods incompressible viscous flows