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Characteristics of Positive Ions in the Sheath Region of magnetized Collisional Electronegative Discharges

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Plasma Science and Technology 2014年第6期16卷 552-556页

作者： m.m.hatami A.R.NIKNAm Physics Department of K.N.Toosi University of Technology Laser-Plasma Research Institute of Shahid Beheshti University G.C.

A hydrodynamic model is used to investigate the characteristics of positive ions in the sheath region of a low-pressure magnetized electronegative discharge. Positive ions are modeled as a cold fluid, while the electron and negative ion density distributions obey the Boltzmann distribution with two different temperatures. By taking into account the ion-neutral collision effect in the sheath region and assuming that the momentum transfer cross section has a power law dependence on the velocity of positive ions, the sheath formation criterion （modified Bohm＇s criterion） is derived and it is shown that there are specified maximum and minimum limits for the ion mach number m. Considering these two limits of m, the behaviors of electrostatic potential, charged particle density distributions and positive ion velocities in the sheath region are studied for different values of ion-neutral collision frequency.

关键词： electronegative plasma hydrodynamic model magnetized plasma sheath,Bohm's criterion

Effect of Ion Concentrations on the Characteristics of a multi-Component magnetized Plasma Sheath

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Plasma Science and Technology 2009年第6期11卷 642-646页

作者： m.m.hatami B.SHOKRI Laser-Plasma Research Institute of Shahid Beheshti University G.C.EvinTehranIran Physical Department and Laser-Plasma Research Institute of Shahid Beheshti University G.C.EvinTehranIran

A hydrodynamic approach is used to investigate a three-component magnetized plasma sheath which consists of electrons and two species of positive ions. Assuming a phase space of one-dimensional spatial coordinate system and three-dimensional velocity coordinate system, the effect of different concentrations of positive ion species on some characteristics of the plasma sheath such as the velocity and density distribution of positive ion species and the electrostatic potential of this region is investigated. The calculated results show that the increase in the density ratio of positive ion species causes a decrease in both the ion velocities and the electrostatic potential of the sheath region. Also, it is shown that in the sheath region of a magnetized plasma consisting of only one positive ion species the bumps of the net density of charged particles disappears much faster. In addition, three-dimensional velocity of each positive ion species in the sheath region is plotted for different concentrations of positive ion species.

关键词： magnetized plasma plasma and electropositive plasma sheath hydrodynamic equations multi-component sheath

motion of a spherical particle in a fluid forced vortex by DQm and DTm

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Particuology 2014年第5期12卷 206-212页

作者： m.hatami D.D.Ganji Esfarayen University Department of Mechanical EngineeringEsfarayenNorth KhorasanIran mechanical Engineering Faculty Babol University of TechnologyBabolP.O.Box 484Iran

In this study, coupled equations of the motion of a particle in a fluid forced vortex were investigated using the differential transformation method （DTm） with the Pad6 approximation and the differential quadrature method （DO_m）. The significant contribution of the work is the introduction of two new, fast and efficient solutions for a spherical particle in a forced vortex that are improvements over the previous numerical results in the literature. These methods represent approximations with a high degree of accuracy and minimal computational effort for studying the particle motion in a fluid forced vortex. In addition, the velocity profiles （angular and radial） and the position trajectory of a particle in a fluid forced vortex are described in the current study.

关键词： Spherical particle Forced vortex Differential transformation method (DTm)Angular velocity Differential quadrature method (DQm)

Quantum phase distribution and the number-phase Wigner function of the generalized squeezed vacuum states associated with solvable quantum systems

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Chinese Physics B 2012年第5期21卷 265-273页

作者： G.R.Honarasa m.K.Tavassoly m.hatami Department of Physics Faculty of ScienceShiraz University of Technology Atomic and molecular Group Faculty of PhysicsYazd University

The quantum phase properties of the generalized squeezed vacuum states associated with solvable quantum systems are studied by using the Pegg-Barnett ***,two nonclassical features,i.e.,squeezing in the number and phase operators,as well as the number-phase Wigner function of the generalized squeezed states are *** to some actual physical situations,the present approach is applied to two classes of generalized squeezed states：solvable quantum systems with discrete spectra and nonlinear squeezed states with particular nonlinear ***,the time evolution of the nonclassical properties of the considered systems has been numerically investigated.

关键词： squeezed vacuum states solvable quantum systems phase distribution number phaseWigner function

Exact Solutions of the Dirac Equation for an Electron in a magnetic Field with Shape Invariant method

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Chinese Physics Letters 2008年第11期25卷 3848-3851页

作者： m. R. Setare O. hatami Department of Science University of Kurdistan Pasdaran Ave. Sanandaj Iran

Based on the shape invariance property we obtain exact solutions oI the Dirac equation for an electron moving in the presence of a certain varying magnetic field, then we also show its non-relativistic limit.

关键词： the power-law exponents precipitation durative abrupt precipitation change

Exact Solution of Klein-Gordon Equation for Charged Particle in magnetic Field with Shape Invariant method

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Communications in Theoretical Physics 2009年第6期51卷 1000-1002页

作者： m.R. Setare O. hatami Department of Science University of Kurdistan Pasdaran Ave. Sanandaj Iran

Based on the shape invariance property we obtain exact solutions of the three-dimensional relativistic Klein Gordon equation for a charged particle moving in the presence of a certain varying magnetic field, and we al... 详细信息

关键词： Klein Gordon equation shape invariance supersymmetric quantum mechanics exact solutions magnetic field

Analysis of turbulent mHD Couette nanofluid flow and heat transfer using hybrid DTm-FDm

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Particuology 2016年第3期14卷 95-101页

作者： S. mosayebidorcheh m. Sheikholeslami m. hatami D.D. Ganji Young Researchers and Elite Club Najafabad Branch lslamicAzad University Ndjafabad Iran Department of mechanical Engineering Lenjan Branch Islamic Azad University lsfahan Iron Department of mechanical Engineering Babol University of Technology Babol Iran mechanical Engineering Department Engineering and Technical College Esfarayen University Esfarayen North Khorasan lran

Unsteady turbulent magnetohydrodynamic nanofluid hydrothermal treatment is studied. The zero- equation turbulence model is used to simulate turbulent flow. The modeling results obtained by applying the hybrid differential transformation method-finite difference method to solve this problem confirm its viability. An analytical procedure is used for finding the effects of the problem parameters. Results indicate that the average Nusselt number over the lower plate depends linearly on volume fraction of nanofluid, Hall parameter, turbulent Eckert number, and Reynolds number whereas it is inversely proportional on the Hartmann number and the turbulent parameter.

关键词： Turbulent Hall effect Hybrid DTm-FDm Nanofluid magnetohydrodynarnic couette flow

Quantum Squeezing of Dark Solitons in Optical Fibers

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Communications in Theoretical Physics 2011年第8期56卷 322-326页

作者： G.R.Honarasa m.hatami m.K.Tavassoly Atomic and molecular Group Faculty of PhysicsYazd University Physics Group Faculty of ScienceShiraz University of Technology

The quantum theory of dark soliton propagation in fibers is studied based on the linearization approximation. Then the uncertainties in photon number, phase, position （time） and momentum of quantized dark solitons are calculated. Finally, the squeezing of the dark soliton is investigated by using homodyne detection and compared with bright soliton case.

关键词： squeezing dark soliton quantum nonlinear Schrodinger equation quantum fluctuation

Investigation of third-grade non-Newtonian blood flow in arteries under periodic body acceleration using multi-step differential transformation method

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Applied mathematics and mechanics(English Edition) 2015年第11期36卷 1449-1458页

作者： m.hatami S.E.GHASEmI S.A.R.SAHEBI S.mOSAYEBIDORCHEH D.D.GANJI J.hatami Department of mechanical Engineering Esfarayen University of Technology Young Researchers and Elite Club Islamic Azad University Deptartment of mechanical Engineering Islamic Azad University Department of mechanical Engineering Babol University of Technology Garmsar Health & Care Center Semnan University of Medical Sciences

In this paper, a non-Newtonian third-grade blood in coronary and femoral arteries is simulated analytically and numerically. The blood is considered as the third- grade non-Newtonian fluid under the periodic body acceleration motion and the pulsatile pressure gradient. The hybrid multi-step differential transformation method （Hybrid-ms- DTm） and the Crank-Nicholson method （CNm） are used to solve the partial differential equation （PDE）, and a good agreement between them is observed in the results. The effects of the some physical parameters such as the amplitude, the lead angle, and the body acceleration frequency on the velocity and shear stress profiles are considered. The results show that increasing the amplitude, Ag, and reducing the lead angle of body acceleration, 9, make higher velocity profiles on the center line of both arteries. Also, the maximum wall shear stress increases when Ag increases.

关键词： pulsatile blood third-grade non-Newtonian fluid differential transforma-tion method (DTm) femoral artery coronary artery