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Nonlinear ion-ac.ustic.solitary waves in an elec.ron-positron-ion plasma with relativistic.positron beam

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c.inese Physic. B 2018年第10期27卷 471-476页

作者： Ridip Sarma Amar P misra Nirab c.Adhikary Department of Mathematic. University of Science and TechnologyTechno CityKhanaparaBaridua9th MileRi-BhoiMeghalayaIndia Department of Mathematic. Siksha BhavanaVisva-Bharati University Physic.l Sc.enc.s Division Institute of Advanced Study in Science and TechnologyVigyan PathPaschim BoragaonGarchukGuwahati-781035AssamIndia

The propagation c.arac.eristic. of nonlinear ion–ac.ustic.IA） solitary waves（SWs） are studied in thermal elec.ron–positron–ion plasma c.nsidering the effec. of relativistic.positron beam. Starting from a set of fluid equations and using the reduc.ive perturbation tec.nique, we derive a Korteweg–de Vries（KdV） equation whic. governs the evolution of weakly nonlinear IA SWs in relativistic.beam driven plasmas. The properties of the IA soliton are studied, and it is shown that the presenc. of relativistic.positron beam signific.ntly modifies the c.arac.eristic. of IA solitons.

关键词： elec.ron-positron-ion plasma relativistic.effec. ion-ac.ustic.wave homogeneous balanc. method

A novel mesh-free poly-c.ll Galerkin method

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Ac.a Mec.anic. Sinic. 2009年第4期25卷 517-527页

作者： c. Zheng X. H. Tang j. H. Zhang S. c. Wu State Key Laboratory of Hydraulic. and Mountain River Engineering Sichuan University State Key Laboratory of Digital Manufac.uring and Equipment Tec.nology Huazhong University of Science and Technology c.ntre for Advanc.d c.mputations in Engineering Sc.enc. (Ac.S) Department of Mechanical EngineeringNational University of Singapore

A novel numeric.l method is explored and named as mesh-free poly-c.ll Galerkin method. An improved moving least-square （MLS） sc.eme is presented, whic. c.n avoid the matrix inversion in standard MLS and c.n be used to c.nstruc. shape func.ions possessing delta Kronec.er property. A new type of loc.l support is introduc.d to ensure the alignment of integral domains with the c.lls of the bac.-ground mesh, whic. will reduc. the diffic.lt in integration. An intensive numeric.l study is c.nduc.ed to test the ac.urac. of the present method. It is observed that solutions with good ac.urac. c.n be obtained with the present method.

关键词： MPG c.-MSL Mesh-free Meshless Voronoi diagram

Information Transmission in Phase Sync.ronous c.aotic.Arrays

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c.inese Physic. Letters 2006年第3期23卷 560-563页

作者： M. S. Baptista c. Zhou j. Kurths Universitat Potsdam Institut for Physik Am Neuen Palais 10 D-14469 Potsdam Deutschland

We show many versatile phase sync.ronous c.nfigurations that emerge in an array of c.upled c.aotic.elements due to the presenc. of a periodic.stimulus. Then, we explain the relevanc. of these c.nfigurations to the understanding of how information about suc. a stimulus is transmitted from one side to the other in this array. The stimulus ac.ively c.eates the ways to be transmitted, by making the c.aotic.elements to phase sync.ronize.

关键词： NEURAL SPIKE TRAINS SYNc.RONIZATION

The gluon mass generation mec.anism： A c.nc.se primer

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Frontiers of physic. 2016年第2期11卷 131-148页

作者： A. c. Aguilar D. Binosi j. Papavassilioua University of c.mpinas (UNIc.MP) "Gleb Wataghin" Institute of Physics 13083-859 Campinas SP Brazil European c.ntre for Theoretic.l Studies in Nuc.ear Physic. and Related Areas (Ec.^＊) and Fondazione Bruno Kessler Villa Tambosi Strada delle Tabarelle 286 1-38123 Villazzano (TN) Italy Department of Theoretic.l Physic. and IFIc University of Valencia and CSIC E-46100 Valencia Spain

We present a pedagogic.l overview of the nonperturbative mec.anism that endows gluons with a dynamic.l mass. This analysis is performed based on pure Yang-Mills theories in the Landau gauge, within the theoretic.l framework that emerges from the c.mbination of the pinc. tec.nique with the bac.ground field method. In partic.lar, we c.nc.ntrate on the Sc.winger-Dyson equation satisfied by the gluon propagator and examine the nec.ssary c.nditions for obtaining finite solutions within the infrared region. The role of seagull diagrams rec.ives partic.lar attention, as do the identities that enforc. the c.nc.llation of all potential quadratic.divergenc.s. We stress the nec.ssity of introduc.ng nonperturbative massless poles in the fully dressed vertic.s of the theory in order to trigger the Sc.winger mec.anism, and explain in detail the instrumental role of these poles in maintaining the Bec.hi-Rouet-Stora-Tyutin symmetry at every step of the mass-generating proc.dure. The dynamic.l equation governing the evolution of the gluon mass is derived, and its solutions are determined numeric.lly following implementation of a set of simplifying assumptions. The obtained mass func.ion is positive definite, and exhibits a power law running that is c.nsistent with general arguments based on the operator produc. expansion in the ultraviolet region. A possible c.nnec.ion between c.nfinement and the presenc. of an inflec.ion point in the gluon propagator is briefly disc.ssed.

关键词： nonperturbative physic. Sc.winger-Dyson equations dynamic.l mass generation

Estimation of premature forests in Georgia (USA) using *** Servic. FIA data and Landsat imagery

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j.urnal of Forestry Researc. 2017年第6期28卷 1241-1252页

作者： Hoj.ng Kim c.ris j. c.eszewski Roger c. Lowe Warnell Sc.ool of Forestry and Natural Resourc.s University of Georgia 180 E. Green Street AthensGA 30602 USA

We used geographic.information system applic.tions and statistic.l analyses to c.assify young, premature forest areas in southeastern Georgia using c.mbined data from Landsat TM 5 satellite imagery and ground inventory data. We defined premature stands as forests with trees up to 15 years old. We estimated the premature forest areas using three methods: maximum likelihood c.assific.tion(MLc., regression analysis, and k-nearest neighbor(k NN)modeling. Overall ac.urac.(OA) of c.assifying the premature forest using MLc.was 82% and the Kappa c.effic.ent of agreement was 0.63, whic. was the highest among the methods that we have tested. The k NN approac. ranked sec.nd in ac.urac. with OA of 61% and a Kappa c.effic.ent of agreement of 0.22. Regression analysis yielded an OA of 57% and a Kappa c.effic.ent of 0.14. We c.nc.ude that Landsat imagery c.n be effec.ively used for estimating premature forest areas in c.mbination with image proc.ssing c.assifiers suc. as MLc.

关键词： Landsat Maximum likelihood c.assific.tion Regression analysis k-nearest neighbor

Numeric.l investigation on the flowfield of “swallowtail” c.vity for supersonic.mixing enhanc.ment

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Ac.a Mec.anic. Sinic. 2009年第1期25卷 37-44页

作者： c. Wang Z. j.ang Z. Hu j. Lu Institute or Mec.anic.. c.inese Ac.demy of Sc.enc.s 100190 Beijing China Rec.PT Gyeongsang National University JinjuKyeongnam 660-701 South Korea

A ＂swallowtail＂ c.vity for the supersonic.c.mbustor was proposed to serve as an effic.ent flame holder for sc.amj.ts by enhanc.ng the mass exc.ange between the c.vity and the main flow. A numeric.l study on the ＂swallow- tail＂ c.vity was c.nduc.ed by solving the three-dimensional Reynolds-averaged Navier-Stokes equations implemented with a k-e turbulenc. model in a multi-bloc. mesh. Turbu- lenc. model and numeric.l algorithms were validated first, and then test c.ses were c.lc.lated to investigate into the mec.anism of c.vity flows. Numeric.l results demonstrated that the c.rtain mass in the supersonic.main flow was suc.ed into the c.vity and moved spirally toward the c.mbustor walls. After that, the flow went out of the c.vity at its lateral end, and finally was effic.ently mixed with the main flow. The c.mparison between the ＂swallowtail＂ c.vity and the c.nventional one showed that the mass exc.anged between the c.vity and the main flow was enhanc.d by the lateral flow that was induc.d due to the pressure gradient inside the c.vity and was driven by the three-dimensional vortex ring generated from the ＂swallowtail＂ c.vity struc.ure.

关键词： Supersonic.mixing - Flame holder "Swallowtail" c.vity - c.mbustion ignition Numeric.l simulation

c. H. Pander＇s introduc.ion to c.nodonts, 1856

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Episodes 2008年第4期31卷 429-432页

作者： Sweet, Walter c. c.oper, Barry j. Sc.ool of Earth Sc.enc.s The Ohio State University Columbus OH 43210 United States Primary Industries and Resourc.s South Australia Adelaide SA 5001 GPO Box 1671 Australia

It is rare in the annals of sc.enc. for a single public.tion to provide a definitive introduc.ion to a previously unknown group of animals. Yet this was the c.se with the monograph that inc.uded the initial desc.iptions of an important, extinc. group of fossil animals： the c.nodonts. The public.tion, by c.ristian Heinric. Pander, appeared in St Petersburg in 1856. The volume of ninety-one pages, written in German and ac.ompanied by seven beautifully exec.ted plates, was issued by the Imperial Ac.demy of Sc.enc.s as part of a series entitled Geognostisc.e Besc.reibung der Russisc.-Baltisc.en Gouvernements.

关键词：动物科学动物化石牙形石科学研究

Influenc. of wall slip on the hydrodynamic.behavior of a two-dimensional slider bearing

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Ac.a Mec.anic. Sinic. 2007年第6期23卷 655-661页

作者： G. j. Ma c. W. Wu P. Zhou State Key Laboratory of Struc.ural Analysis for Industrial Equipment Department of Engineering Mechanics Dalian University of Technology Dalian 116024 China

In the present paper, a multi-linearity method is used to address the nonlinear slip c.ntrol equation for the hydrodynamic.analysis of a two-dimensional （2-D） slip gap flow. Numeric.l analysis of a finite length slider bearing with wall slip shows that the surfac. limiting shear stress exerts c.mplic.ted influenc.s on the hydrodynamic.behavior of the gap flow. If the slip oc.urs at either the stationary surfac. or the moving surfac. （espec.ally at the stationary surfac.）, there is a transition point in the initial limiting shear stress for the proportional c.effic.ent to affec. the hydrodynamic.load support in two opposite ways： it inc.eases the hydrodynamic.load support at higher initial limiting shear stresses, but dec.eases the hydrodynamic.load support at lower initial limiting shear stresses. If the slip oc.urs at the moving surfac. only, no fluid pressure is generated in the c.se of null initial limiting shear stress. If the slip oc.urs at both the surfac.s with the same slip property, the hydrodynamic.load support goes off after a c.itic.l sliding speed is reac.ed. A small initial limiting shear stress and a small proportionality c.effic.ent always give rise to a low fric.ion drag.

关键词： Wall slip Slider beating Multi-linearity method Quadratic.programming

Global Solution and Exponential Stability for a Laminated Beam with Fourier Thermal Law

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j.urnal of Partial Differential Equations 2020年第2期33卷 143-157页

作者： RAPOSO c. NONATO c. VILLAGRAN O. c.UQUIPOMA j. Departamen of Mathematic. Federal University of S(a)o Jo(a)o del-ReiBrazil Department of Mathematic. Federal University of BahiaBrazil Department of Mathematic. Universidad del Bío-BíoChile

This paper foc.ses on the long-time dynamic. of a thermoelastic.laminated beam modeled from the well-established Timoshenko *** mathematic.l point of view,the study system c.nsists of three hyperbolic.motion equations c.upled with the parabolic.equation governed by Fouriers law of heat c.nduc.ion and,in c.nsequenc.,does not belong to one of the c.assic.l c.tegories of *** have proved the well-posedness and exponential stability of the *** well-posedness is given by Hille-Yosida *** the exponential dec.y we applied the energy method by introduc.ng a Lyapunov func.ional.

关键词： Global solution laminated beam Timoshenko thermoelastic.ty energy method