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Computer Simulation Study of Thermal Conduction in 1D Chains of Anharmonic Oscillators

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Communications in Theoretical physics 2013年第3期59卷 361-364页

作者： Tejal n.Shah p.n.gajjar Bhavan's Sheth R.A.College of Science KhanpurAhmedabad 380 001GujaratIndia Department of physics University School of SciencesGujarat UniversityAhmedabad 380 009GujaratIndia

In this work thermal conduction in one-dimensional （1D） chains of anharmonic oscillators are studied using computer simulation. The temperature profile, heat flux and thermal conductivity are investigated for chain length n = 100, 200, 400, 800 and 1600. In the computer simulation anharmonicity is introduced due to Fermi-pasta- U1am-β （FpU-β） model For substrate interaction, an onsite potential due to Frenkel-Kontorova （FK） model has been used. numerical simulations demonstrate that temperature gradient scales behave as n-1 linearly with the relation J = 0.1765/n. For the thermal conductivity K, Kn to n obey the linear relation of the type Kn = 0.8805n. It is shown that thermal transport is dep.n.ent on phonon-phonon interaction as web as phonon-lattice interaction. The thermal conductivity increases linearly with increase inanharmonicity and predicts relation κ =0.133 ＋ 0.804β. It is also concluded that for higher value of the strength of the onsite potential system tends to a thermal insulator.

关键词： heat conduction thermal conductivity Anharmonic oscillator Fermi-pasta-Ulam model Frenkel-Kontorova model

A new Method for Characterizing Single parametric Model potential

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Communications in Theoretical physics 2008年第9期50卷 763-766页

作者： p.S.Vyas p.n.gajjar B.Y.Thakore A.R.Jani Department of physics Sardar Patel UniversityVallabh Vidyanagar 388 120GujaratIndia Department of physics University School of SciencesGujarat UniversityAhmedabad 380 009GujaratIndia

A novel approach of characterizing single parametric model potential is proposed by equating total pair wise force to zero. Our well-established single parametric model potential is characterized using the proposed idea and compared the obtained parameter with parameters computed by previously used approaches. Thus characterized pseudopotential is then tested to compute total energy of alkali metals. The results establish the reliability of proposed idea of making total pair wise force to zero in determining the parameter of the pseudopotential.

关键词： pseudopotential alkali metals interatomic force bulk modulus

Some properties of Si,Ge,and α-Sn Using pseudopotential Theory

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Communications in Theoretical physics 2010年第9期54卷 573-577页

作者： p.S.Vyas B.Y.Thakore p.n.gajjar A.R.Jani Department of physics Sardar Patel University Department of physics University School of SciencesGujarat University

The pseudopotential theory beyond second order with our well established single parametric model potential is employed to compute total crystal energy, static bulk modulus, energy band gap at the point X on the Jones-zone face and pressure-volume relation （equation of state under pressure） of Si, Ge and α-Sn using nagy＇s static local field correction function. The results are compared with those obtained using few other local field correction functions. The present results of total energy are in good agreement with the experimental data. Bulk modulus calculated by nagy＇s screening function is perfectly matching with the experimental results for Ge and α-Sn. Some deviation is found in the value of energy band gap.

关键词： pseudopotential total energy semiconductor bulk modulus

Dielectric spectroscopy and structural characterization of nano-filler-loaded epoxy resin

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Journal of Advanced Dielectrics 2021年第2期11卷 15-26页

作者： S.G.Thakor V.A.Rana H.p.Vankar T.R.p.n.it Department of physics School of SciencesGujarat University Ahmedabad 380009GujaratIndia

This work outlines the characterization of epoxy resin[Bisphenol A-(epichlorhydrin):epoxy]and hardener[n(3-dimethylaminopropyl)-1,3-propylenediamine]with various inorganic *** characterizations of epoxy,hardener,neat epoxy(epoxy+hardener)and nano-epoxy(nano-filler+neat epoxy)composites loaded with 1 wt.%of inorganic nano-fillers(SiO_(2),Al_(2)O_(3),TiO_(2)and ZnO)were carried out using precision LCR meter,over the frequency range of 1 kHz-2 MHz at a constant temperature of 300.15 *** structural information of nano-fillers,neat epoxy and nano-epoxy composites was understood by Fourier transform infrared spectroscopy and by ***,hardness and shear strength(shear p.n.h)were also determined in order to gain additional information about the mechanical properties of epoxy *** of inorganic nano-fillers on the dielectric properties,structural chemistry and mechanical properties of neat epoxy composite is discussed thoroughly in this study.

关键词： Epoxy resin nano-fillers dielectric relaxation spectroscopy FTIR mechanical properties XRD