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Numerical Simulation of Bubble Cluster Dynamics, Using Lattice Boltzmann Method
, Ph.D. Dissertation Sharif University of Technology ; Tayyebi Rahni, Mohammad (Supervisor) ; Massah, Hamid Reza (Co-Advisor)
Abstract
Bubble cluster has attracted the interests of many researches since the early twentieth century. Despite its easy generation and numerous occurrences, its study is extremely complex. Describing the dynamical behavior of bubble clusters is possible when quite a few simplifying assumptions are utilized. In other words, one can observe that with current approaches, the relevant theoretical researches are not very valuable. In this research, however, lattice Boltzmann method, a rather recent mesoscopic approach, was used to study the behavior of bubbles in a bubble cluster. Of course, this is only the beginning and there is a long way before getting close to experimental results. However, there...
First principles study of oxygen adsorption on nickel-doped graphite
, Article Molecular Physics ; Volume 110, Issue 13 , Feb , 2012 , Pages 1437-1445 ; 00268976 (ISSN) ; Gobal, F ; Sharif University of Technology
2012
Abstract
Density functional theory is used in a spin-polarized plane wave pseudopotential implementation to investigate molecular oxygen adsorption and dissociation on graphite and nickel-doped graphite surfaces. Molecular oxygen physisorbs on graphite surface retaining its magnetic property. The calculated adsorption energy is consistent with the experimental value of 0.1eV. It is found that substituting a carbon atom of the graphite surface by a single doping nickel atom (2.8% content) makes the surface active for oxygen chemisorption. It is found that the molecular oxygen never adsorbs on doping nickel atom while it adsorbs and dissociates spontaneously into atomic oxygens on the carbon atoms...
First-principle electronic structure calculation of BaFe2-x Cox As2 (X = 0,1, 2) superconductor
,
Article
Journal of Superconductivity and Novel Magnetism
;
Volume 28, Issue 8
,
August
,
2015
,
Pages 2249-2254
;
15571939 (ISSN)
; Khosroabadi, H
; Akhavan, M
;
Sharif University of Technology
Springer New York LLC
2015
Abstract
The equilibrium crystal structure and electronic structure of BaFe2-x Cox As2 (x = 0,1, 2) superconductor have been investigated by using the pseudopotential Quantum Espresso code based on the ab initio density functional theory in the generalized gradient approximation. The equilibrium crystal structure for x = 1.0 has been determined by considering five different Fe/Co configurations. This study shows that the spin calculation is essential to obtain the experimental values at x = 0.0. The total and partial density of states, band structure, and Fermi surfaces of the three compounds has been calculated. Density of states calculation indicates the important...
Electronic structure of Ni-doped BaFe2−x Nix As2 (x = 0, 1, 2) superconductor in the nonmagnetic and magnetic states
,
Article
Journal of Superconductivity and Novel Magnetism
;
Volume 28, Issue 8
,
2015
,
Pages 2365-2371
;
15571939 (ISSN)
; Khosroabadi, H
; Abolhassani, M. R
;
Sharif University of Technology
Springer New York LLC
2015
Abstract
The spin configuration, equilibrium crystal structure, and electronic structure of BaFe2 −x Nix As2 (x = 0, 1, 2) have been investigated by using ab initio pseudopotential Quantum Espresso code in the generalized gradient approximation. The total energy of different Fe(Ni) spin configurations has been calculated to determine the ground state in each doping. The results show an antiferromagnetic order in x = 0.0 and a nonmagnetic state for x = 2.0. Equilibrium lattice and internal parameters for this system have been calculated and compared with the literature data. This study shows that the lattice parameters in the magnetic calculations have been...
Electronic and phonon structures of BaFe2As2 superconductor by Ab-initio density functional theory
, Article Journal of Superconductivity and Novel Magnetism ; Volume 26, Issue 1 , January , 2013 , Pages 93-100 ; 15571939 (ISSN) ; Khosroabadi, H ; Almasi, H ; Akhavan, M ; Sharif University of Technology
2013
Abstract
Electronic and phonon structures of the BaFe2As2 superconductor in the magnetic-orthorhombic phase have been investigated by the ab-initio density functional theory using the pseudopotential Quantum Espresso code. Density of state and electronic band structure for this phase has been studied, but phonon dispersion has been obtained only for the nonmagnetic-orthorhombic phase. Electronic band structure and density of states are in good agreement with other calculations in the literature. The electronic state near the Fermi energy are essentially made from Fe3d and As4p orbital that indicate in-plane conductivity in FeAs layers in this system. Comparing calculated phonon dispersions with...
Effects of K doping on electronic structure of Ba1-xKxFe2As2 superconductor by ab-initio density functional theory
, Article Physica C: Superconductivity and its Applications ; Vol. 507, issue , Dec , 2014 , p. 22-24 ; Khosroabadi, H ; Akhavan, M ; Sharif University of Technology
Abstract
The crystal and electronic structures of normal phase of Ba1-xKxFe2As2 for x = 0.0, 0.5 and 1.0 have been studied by using pseudopotential Quantum Espresso code based on ab-initio density functional theory. Effects of K doping on the crystal structure and lattice parameters have been calculated and compared with the experimental and computational reported data for similar compounds. The metal-metal bonding scenario was used to explain the changes of lattice parameters by K doping. The electronic structure of this system including of density of states and band structure have been calculated and investigated by K doping. One of the interesting results is that a larger peak is appeared near the...
Effects of fluorine doping and pressure on the electronic structure of lao1−x fx feas superconductor: a first principle study
, Article Journal of Superconductivity and Novel Magnetism ; Volume 30, Issue 8 , 2017 , Pages 2065-2071 ; 15571939 (ISSN) ; Khosroabadi, H ; Sharif University of Technology
Springer New York LLC
2017
Abstract
The effects of fluorine doping on the electronic structure of LaO1−xFxFeAs superconductor have been investigated by ab initio density functional theory using pseudopotential quantum espresso code. Firstly, we have studied the role of fluorine doping on the electronic structure of LaO1−xFxFeAs by calculation of band structure, density of states, and Fermi surfaces at various doping levels x = 0.00, 0.25, and 0.50. The lattice parameters and ionic position have been determined by optimizing crystal structure. Our results show that doping decreases cell volume similar to mechanical pressure and shifts the bands and states near the Fermi level toward the lower energies. According to the Fermi...