检索结果-南通市图书馆

A Coupled Variable Coefficient Modified KdV Equation Arising from a Two-Layer Fluid System

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2007年第12期48卷 961-970页

作者： GAO Yuan~1 and TANG Xiao-Yan~(1,2)~1 Department of Physics,Shanghai Jiao Tong University,Shanghai 200240,China~2 Institut Für Theoretische physik IV,Fakultt für physik und Astronomie,Ruhr-Universitt Bochum,D-44870 Bochum,Germany Department of Physics Shanghai Jiao Tong University Institut Fur Theoretische physik IV Fakultat fur Physik und Astronomie Ruhr-Universitat Bochum

A quite general coupled variable coefficient modified KdV (VCmKdV) equation in a two-layer fluid systemis derived by means of the reductive perturbation *** use of the CK's direct method,some similarityreductions of the coupled VCmKdV equation are obtained and their corresponding group explanations are *** exact solutions of the coupled equations are also presented.

关键词： coupled variable coefficient mKdV equation two-layer fluid similarity solution periodic waves

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2008年第1期49卷 229-230页

作者： TANG Xiao-Yan Padma Kant Shukla Department of Physics Shanghai Jiao Tong University Shanghai 200240 China Institut fur Theoretische physik IV Fakultat fur Physik und Astronomie Ruhr-Universitat Bochum D-44870 Bochum Germany School of Physics University of KwaZulu-Natal 4000 Durban South Africa

Applying the classical Lie symmetry approach to the barotropic and quasi-geostrophic potential vorticity equation without forcing and dissipation on a β-plane channel, we find a new symmetry, which is not presented in a previous work [F. Huang, Commun. Theor. Phys. （Beijing, China） 42 （2004） 903]. A general finite transformation group is obtained based on the full Lie point symmetry, Furthermore, two new types of similarity reduction solutions are obtained.

关键词： Lie symmetry similarity reductions potential vorticity equation

An automated, 0.5 Hz nano-foil target positioning system for intense laser plasma experiments

在线全文

学校读者我要写书评

暂无评论

High Power Laser Science and Engineering 2017年第2期5卷 52-56页

作者： Ying Gao Jianhui Bin Daniel Haffa Christian Kreuzer Jens Hartmann Martin Speicher Florian H.Lindner Tobias M.Ostermayr Peter Hilz Thomas F.Rsch Sebastian Lehrack Franz Englbrecht Sebastian Seuferling Max Gilljohann Hao Ding Wenjun Ma Katia Parodi Jorg Schreiber Lehrstuhl fur Medizinphysik Fakultat fUr PhysikLudwig-Maximilians-Universitat MiinchenAm Coulombwall 1D-85748GarchingGermany Max-Planck-lnstitut fur Quantenoptik D-85748 GarchingGermany peking University Beijing 100871PR China

We report on a target system supporting automated positioning of nano-targets with a precision resolution of 4 μm in three dimensions. It relies on a confocal distance sensor and a microscope. The system has been commissioned to position nanometer targets with 1 Hz repetition rate. Integrating our prototype into the table-top ATLAS 300 TW-laser system at the Laboratory for Extreme Photonics in Garching, we demonstrate the operation of a 0.5 Hz laser-driven proton source with a shot-to-shot variation of the maximum energy about 27% for a level of confidence of 0.95. The reason of laser shooting experiments operated at 0.5 Hz rather than 1 Hz is because the synchronization between the nano-foil target positioning system and the laser trigger needs to improve.

关键词： high intense laser nm thick target positioning system repetition rated laser-driven ion source

Investigating color screening in proton-nucleus collisions with complex potentials

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2022年第11期46卷 203-211页

作者： Liuyuan Wen Xiaojian Du Shuzhe Shi Baoyi Chen Department of Physics Tianjin UniversityTianjin 300350China fakultat fur physik Universitat BielefeldD-33615 BielefeldGermany Center for Nuclear Theory Department of Physics and AstronomyStony Brook UniversityStony BrookNew York11784USA

Color screening and parton inelastic scattering modify the heavy-quark antiquark potential in mediums consisting of particles from quantum chromodynamics(QCD),leading to the suppression of quarkonium production in relativistic heavy-ion *** to the small charm/anti-charm(cc)pair production number in proton-nucleus(pA)collisions,the correlation between different cc pairs is negligible,which makes the Schrödinger equation viable for tracking the evolution of only one cc *** employ the time-dependent Schrödinger equation with an in-medium cc potential to study the evolution of charmonium wave functions in a hydrodynamic-like QCD medium produced in pA *** explore different parametrizations of real and imaginary parts of the cc potential and calculate the nuclear modification factors(R_(pA))of J/ψ and ψ(2S)in √s_(NN)=5.02 TeV energy p-Pb collisions at the Large Hadron Collider(LHC).Comparing strong and weak screening scenarios with experimental data in this approach,we arrive at the conclusion that color screening is weak at temperatures close to the deconfined phase ***,the imaginary part of the potential is crucial in describing the experimental data,which is consistent with widely studied semi-classical approaches,where dissociation rates are essential.

关键词： heavy-ion collision quarkonium dissociation quark-gluon plasma Schrödinger equation

Reconstruction of Complex Materials by Integral Geometric Measures

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2002年第2期18卷 155-158页

作者： Klaus R.MeckeMax-Planck-Institut fur Metallforschung, Heisenbergstr.1, D-70569 Stuttgart, Institut fur Theoretische und Angewandte physik, fakultat fiir physik Universitat Stuttgart, Pfaffenwaldring 57, D-70569 Stuttgart, Germany [ Manuscript received Nov fakultat fur Phys. Univ. Stuttgart D-70569Stuttgart Pfaffenwaldring 57 Germany

The goal of much research in computational materials science is to quantify necessary morphological information and then to develop stochastic models which both accurately reflect the material morphology and allow one to estimate macroscopic physical properties. A novel method of characterizing the morphology of disordered systems is presented based on the evolution of a family of integral geometric measures during erosion and dilation operations. The method is used to determine the accuracy of model reconstructions of random systems. It is shown that the use of erosion/dilation operations on the original image leads to a more accurate discrimination of morphology than previous methods.

关键词： Porous media Integral geometry Morphology Erosion Dilation Minkowski functionals Reconstruction

Magnetic-Field-Induced Semimetal-Insulator-like Transition in Highly Oriented Pyrolitic Graphite

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2007年第1期24卷 199-202页

作者：王志明邢定钰张世远徐庆宇 Margriet VanBael 都有为 Institute of Mechanical Engineering Nanjing University of Science and Technology Nanjing 210094 National Laboratory of Solid State Microstructures and Department of Physics Nanjing University Nanjing 210093 Universitat Leipzig Fakultat für Physik und Geowissenschaften Institut ff/r Experimentelle Physik Ⅱ Linnéstrasse 5 D-04103 Leipzig Germany Laboratorium voor Vaste-Stoffysica en Magnetisme Katholieke Universiteit Leuven B-3001 Heverlee Belgium

We report the extraordinarily large positive magnetoresistances （MR, 69400% at 4.5K under a magnetic field of 8.15 T）, de Hass-van Alphen oscillations effect at 10 K and the semimetal-Jnsulator-like transition in a wide range of temperature in highly oriented pyrolitic graphite （HOPG）. Besides a dominating ordinary MR （OMR） mechanism in the free-electron mode, it is realized from qualitative analysis that the Coulomb interacting quasiparticles within graphite layers play some roles. However it is difficult to associate the transition with the simple OMR theory. In order to investigate the possible origins of the transition, further analysis is carried out. It is revealed that the magnetic-field-induced behaviour is responsible for the semimetal-insulator-like transitions in HOPG.

关键词： MAGNETORESISTANCE MAGNETIC fields OSCILLATIONS GRAPHITE

Theoretical and Numerical Stability Analysis of the Liquid Metal Pinch Using the Shallow Water Approximation

维普期刊数据库评论

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 Thermal Science 2008年第3期17卷 261-266页

作者： E. Zienicke Ben-Wen Li A. Thess A. Krazschmar P. Terhoeven Institut fur physik Technische Universitat Ilmenau PF 100565 D-98684 Ilmenau Germany Key Laboratory of National Education Ministry for Electromagnatic Processing of Materials POB 314 NortheasternUniversity Shenyang 110004 China fakultat Maschinenbau Technische Universitat Ilmenau PF 100565 D-98684 Ilmenau Germany Moeller GmbH Hein Moeller Str. 7-11 D-53115 Bonn Germany

The pinch instability for a cylindrical jet of liquid metal passed through by an axial electrical current is investigated. Besides the pinch effect originating from surface tension, the Lorentz force, created by the axial current density and the corresponding azimuthal magnetic field, causes an electromagnetic pinch effect. This effect has drawn attention in electrical engineering, because it can be used in the construction of liquid metal current limit- ers with self-healing properties. In this paper a simple model is derived using the shallow water approximation： the equations describing the full system are reduced to two one-dimensional evolution equations for the axial velocity and the radius of the jet. A stability analysis for this reduced system is carried out yielding critical current density and the growth rate for the instability. To investigate the nonlinear behaviour of the pinch instability for finite perturbations simulations, the shallow water model are performed.

关键词： MHD pinch instability analysis electric current limiter numerical simulation Fourier spectralmethod

Self-diffusion coefficients of organic solvents in linear and branched high density polyethylene particles measured by PFG NMR

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2008年第1期19卷 110-114页

作者： Xiao Wei Yan Xiao Hong Ren Siegfried Stap Jing Dai Wang Yong Rong Yang Department of Chemical Engineering Zhejiang University Hangzhou 310027 China FG Technische physik ll/Polymerphysik Fakultat fiir Mathematik und Naturwissenschaften Technische Universitiit Ilmenau Postfach 100565 D-98684 Ilmenau Germany Institut fiir Technische Chemie und Makromolekulare Chemie RWTH Aachen University Worringerweg 1 D-52056 Aachen Germany

Pulsed field gradient nuclear magnetic resonance （PFG NMR） has been performed to study the diffusion of organic solvents into semicrystalline polyethylene particles. Self-diffusion coefficients in different domains of the sample can be extracted through a bi- exponential fit to the echo intensity attenuation, which allows the precise determination of the tortuosity of the polyethylene particles. Further exploration comes from the measurements with branched polyethylene particles and it was found that the diffusion in polymer phase contributed significantly to the slow component of the exponential decay curve. 2007 Jing Dai Wang. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

关键词： Self-diffusion coefficients Pulsed field gradient NMR Tortuosity Polyethylene particle

Non-Maxwellian electron distributions resulting from direct laser acceleration in near-critical plasmas

在线全文

学校读者我要写书评

暂无评论

Matter and Radiation at Extremes 2016年第1期1卷 82-87页

作者： T.Toncian C.Wang E.McCary A.Meadows A.V.Arefiev J.Blakeney K.Serratto D.Kuk C.Chester R.Roycroft L.Gao H.Fu X.Q.Yan J.Schreiber I.Pomerantz A.Bernstein H.Quevedo G.Dyer T.Ditmire B.M.Hegelich Department of Physics University of TexasAustinTX78712USA State Key Laboratory of Nuclear Physics and Technology Peking UniversityBeijing100871China fakultat fur physik Ludwig-Maximilians-UniversityMunichGermany

The irradiation of few-nm-thick targets by a finite-contrast high-intensity short-pulse laser results in a strong pre-expansion of these targets at the arrival time of the main *** targets decompress to near and lower than critical densities with plasmas extending over few micrometers,*** *** interaction of the main pulse with such a highly localized but inhomogeneous target leads to the generation of a short channel and further self-focusing of the laser *** at the Glass Hybrid OPCPA Scaled Test-bed(GHOST)laser system at University of Texas,Austin using such targets measured non-Maxwellian,peaked electron distribution with large bunch charge and high electron density in the laser propagation *** results are reproduced in 2D PIC simulations using the EPOCH code,identifying direct laser acceleration(DLA)[1]as the responsible *** is the first time that DLA has been observed to produce peaked spectra as opposed to broad,Maxwellian spectra observed in earlier experiments[2].This high-density electrons have potential applications as injector beams for a further wakefield acceleration stage as well as for pump-probe applications.

关键词： Direct laser acceleration Electron acceleration Near critical plasmas PIC simulations