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Advances in Applied mathematics and mechanics 2017年第1期9卷 23-42页

作者： m.r m.soud seyyed fakhrabadi School ofmechanical Engineering College of EngineeringUniversity of TehranTehranIran

The paper presents the size-dependant behaviors of the carbon nanotubes under electrostatic actuation using the modified couple stress theory and homotopy perturbation *** to the less accuracy of the classical elasticity theorems,the modified couple stress theory is applied in order to capture the size-dependant properties of the carbon *** of the static and dynamic behaviors under static DC and step DC voltages are *** effects of various dimensions and boundary conditions on the deflection and pull-in voltages of the carbon nanotubes are to be investigated in detail via application of the homotopy perturbation method to solve the nonlinear governing equations semi-analytically.

关键词： Carbon nanotubes modified couple stress theory homotopy perturbation method electrostatic actuation

Two Bioinspired mobile manipulators with rolling Locomotion

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Journal of Bionic Engineering 2016年第1期13卷 48-58页

作者： Saber mahboubi Heydarabad m.r m.soud seyyed fakhrabadi Steve Davis Samia Nefti-meziani School of Computing Science & Engineering University of Salford Manchester The Crescent M5 4WT UK School of mechanical Engineering College of Engineering University of Tehran Tehran Iran

This paper deals with two novel structures for mobile robots. The original inspiration of the robots comes from a sala- mander and a specific kind of spiders. Our robots have some especial moving capabilities causing to increase the robot ma- neuverability. Indeed, the capability of rolling motion is added to ordinary quadruped robots. This capability causes increment in maneuvering of the robots. manipulators can be embedded into the robots to add the ability of transferring materials into the shell and conducting some tasks such as repairing. In this paper, after analysis of motion principles of the rolling robots, their dynanlic equations are derived. Different simulations of two bioinspired mobile robots are presented in order to scrutinize various capabilities of the proposed designs. Walking capabilities of the robots and their advantages are discussed in detail. The com.rehensive simulation results of the robots in various motion modes are presented. Finally the first prototype is introduced to verify the motion mechanisms.

关键词： bionics rolling robot quadruped robot Lagrange equations

角巩膜镜对圆锥角膜患者视力和角膜参数的影响

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国际眼科杂志 2024年第3期24卷 333-337页

作者： Ali Ayatollahi Haleh Kangari Saeed rahmani seyyed mehdi Tabatabaie Shahid Beheshti医科大学康复学院眼视光系伊朗德黑兰*** Shahid Beheshti医科大学康复学院伊朗德黑兰***

目的:探讨配戴角巩膜接触镜对圆锥角膜患者视力和角膜参数的影响。方法:前瞻性研究。共纳入43例(83眼)圆锥角膜患者。配戴角巩膜接触镜,并分别在戴镜前、戴镜3、6 mo后行裂隙灯检查、客观验光和主观验光、裸眼视力(UCVA)和最佳矫正视力(... 详细信息

目的:探讨配戴角巩膜接触镜对圆锥角膜患者视力和角膜参数的影响。方法:前瞻性研究。共纳入43例(83眼)圆锥角膜患者。配戴角巩膜接触镜,并分别在戴镜前、戴镜3、6 mo后行裂隙灯检查、客观验光和主观验光、裸眼视力(UCVA)和最佳矫正视力(BCVA)、角膜曲率(Kmax、K1和K2)、中央角膜厚度和内皮细胞计数检查。结果:配戴6 mo框架眼镜后平均BCVA(Logm.r)为0.34±0.23,角巩膜接触镜为0.03±0.05(Pmo后,Kmax由52.80±5.93 D变为51.51±5.64 D(Pm变为476.28±35.38μm(Pmm^(2)变为2572.73±274.3 cells/mm^(2)(P<0.001)。结论:临床中角膜参数未发生明显变化,角巩膜镜可显著提高视力,且可安全用于圆锥角膜患者。

关键词：角巩膜接触镜圆锥角膜角膜地形图角膜厚度

Coupled hydroelastic vibrations of an elliptical cylindrical tank with an elastic bottom

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Journal of Hydrodynamics 2014年第2期26卷 264-276页

作者： HASHEmINEJAD seyyed m. TAFANI mostafa Acoustics research Laboratory Center of Excellence in Experimental Solid Mechanics and Dynamics School of Mechanical Engineering Iran University of Science and Technology

An exact three-dimensional analysis based on the linear potential theory and the elaborated method of eigenfunction expansion in elliptic coordinates are presented to study the free coupled elasto-hyrodynamic characteristics of an upright non-deformable cylindrical container of elliptical planform with a flexible bottom plate, filled to an arbitrary depth with an inviscid incom.ressible liquid. Extensive num.rical data are presented in an orderly fashion for the first few symmetric/anti-symmetric coupled hydroelastic natural frequencies as a function of fluid depth parameter for two plate aspect ratios. Also, selected hydrodynamic and structural deformation modes shapes are presented in graphical form. The effects of liquid level, bottom plate elasticity, and cross sectional aspect ratio on the sloshing frequencies and hydrodynamic pressure modes are examined. The validity of the results is examined through computations using a comm.rcial finite element package as well as by comparison with the data available in literature.

关键词： exact solution fluid-structure interaction free surface oscillations vertical elliptical vessel mathieu functions

Eccentricity and thermoviscous effects on ultrasonic scattering from a liquid-coated fluid cylinder

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第1期9卷 65-78页

作者： seyyed m. HASHEmINEJAD m. A. ALIBAKHSHI Acoustics research Lab. Department of Mechanical Engineering Iran University of Science and Technology Narmak Tehran 16844 Iran

Calculation of the scattered field of the eccentric scatterers is an old problem with num.rous applications. This study considers the interaction of a plane com.ressional sound wave with a liquid-encapsulated thermoviscous fluid cylinder subm.rged in an unbounded viscous thermally conducting medium. The translational addition theorem for cylindrical wave functions, the appropriate wave field expansions and the pertinent boundary conditions are employed to develop a closed-form solution in the form of infinite series. The analytical results are illustrated with a num.rical example in which the compound cylinder is insonified by a plane sound wave at selected angles of incidence in a wide range of dimensionless frequencies. The backscattered far-field acoustic pressure amplitude and the spatial distribution of the total acoustic pressure in the vicinity of the cylinder are evaluated and discussed for representative values of the parameters characterizing the system. The effects of incident wave frequency, angle of incidence, fluid thermoviscosity, core eccentricity and size are thoroughly examined. Limiting case involving an ideal com- pressible liquid-coated cylinder is considered and fair agreement with a well-known solution is established.

关键词： Thremoviscous effects Eccentric fluid cylinder Acoustic scattering

Seismic isolation effect of lined circular tunnels with damping treatments

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Earthquake Engineering and Engineering Vibration 2008年第3期7卷 305-319页

作者： seyyed m. Hasheminejad Am.r K. m.ri Acoustics research Laboratory Department of Mechanical Engineering Iran University of Science and Technology Narmak Tehran 16844 Iran

The Havriliak-Negami model for dynamic viscoelastic material behavior and Biot＇s theory of poroelasticity are employed to develop an exact solution for three-dimensional scattering effect of harmonic plane P-SV waves from a circular cavity lined with a multilayered fluid-filled shell of infinite length containing viscoelastic damping materials and embedded within a fluid-saturated permeable surrounding soil medium. The analytical results are illustrated with num.rical examples where the effects of liner/coating structural arrangement, viscoelastic material properties, liner-soil interface bonding condition, seismic excitation frequency, and angle of incidence on the induced dynamic stress concentrations are evaluated and discussed to obtain representative values of the parameters that characterize the system. It is demonstrated that incorporating viscoelastic damping materials with a low shear modulus in the constrained layer configuration is an efficient means of enhancing the overall seismic isolation performance, especially for near-normally incident seismic shear waves where the amplitudes of induced dynamic stresses may be reduced by up to one-third of those without isolation in a relatively wide frequency range. Some additional cases are considered and good agreements with solutions available in the literature are obtained.

关键词： underground tunnel permeable soil seismic wave scattering flee/constrained layer damping

Enhanced Kerr nonlinearity in a quantized four-level graphene nanostructure

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Chinese Physics B 2016年第7期25卷 234-238页

作者： Ghahraman Solookinejad m Panahi E Ahmadi seyyed Hossein Asadpour Department of Physics Marvdasht Branch Islamic Azad University

In this paper, a new model is proposed for manipulating the Kerr nonlinearity of right-hand circular probe light in a monolayer of graphene nanostructure. By using the density matrix equations and quantum optical approach, the third-order susceptibility of probe light is explored num.rically. It is realized that the enhanced Kerr nonlinearity with zero linear absorption can be provided by selecting the appropriate quantities of controllable parameters, such as rabi frequency and elliptical parameter of elliptical polarized coupling field. Our results may be useful applications in future all-optical system devices in nanostructures.

关键词： Kerr nonlinearity graphene nanostructure linear absorption

Optical bistability and multistability via double dark resonance in graphene nanostructure

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Chinese Physics B 2016年第6期25卷 223-229页

作者： seyyed Hossein Asadpour G Solookinejad m Panahi E Ahmadi Sangachin Department of Physics Marvdasht BranchIslamic Azad University

Electrons in graphene nanoribbons can lead to exceptionally strong optical responses in the infrared and terahertz regions owing to their unusual dispersion ***,on the basis of quantum optics and solid-material scientific principles,we show that optical bistability and multistability can be generated in graphene nanostructure under strong magnetic *** also show that by adjusting the intensity and detuning of infrared laser field,the threshold intensity and hysteresis loop can be manipulated *** effects of the electronic cooperation parameter which are directly proportional to the electronic number density and the length of the graphene sample are *** proposed model may be useful for the nextgeneration all-optical systems and information processing based on nano scale devices.

关键词： optical bistability optical multistability graphene nanostructure

CFD modeling of a spouted bed with a porous draft tube

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Particuology 2010年第5期8卷 415-424页

作者： Salar Azizi seyyed Hossein Hosseini m.m.raveji Goodarz Ahmadi Chemical Engineering Department Faculty of EngineeringArak University Department of Chemical Engineering Faculty of EngineeringIlam University Department of mechanical and Aeronautical Engineering Clarkson University

Spouted bed with a porous draft tube is used for drying of grains and chemical products and thermal disinfestations process. This work provides a computational fluid dynamics （CFD） simulation of binary mixtures of glass particles in a spouted bed with a porous draft tube. The simulation used the multi-fluid Eulerian-Eulerian approach based on kinetic theory of granular flows, incorporating a kinetic-frictional constitutive model for dense assemblies of particulate solids and Gidaspow＇s drag model for the interaction between gas and particles. Influences of solids mass fraction and inlet gas flow rate on pressure distribution, gas and particle velocities were studied. The modeling results were compared with the exper- imental work of Ishikura, Nagashima, and Ide （2003） for the flow condition along the axis of the spouted bed. Good agreement between the modeling results and experimental data was observed.

关键词： Spouted bedPorous dra tubeHydrodynamicsKinetictheoryCFD

Optical bistability and multistability in a defect slab doped by GaAs/AlGaAs multiple quantum wells

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Chinese Physics B 2016年第5期25卷 223-228页

作者： seyyed Hossein Asadpour G Solookinejad m Panahi E Ahmadi Sangachin Department of Physics Marvdasht Branch Islamic Azad University

We proposed a new model for controlling the optical bistability（OB） and optical multistability（Om） in a defect slab doped with four-level GaAs/AlGaAs multiple quantum wells with 15 periods of 17.5 nm GaAs wells and 15-nm Al_（0.3）Ga_（0.7）As barriers. The effects of biexciton energy renormalization, exciton spin relaxation, and thickness of the slab on the OB and Om properties of the defect slab were theoretically investigated. We found that the transition from OB to Om or vice versa is possible by adjusting the controllable parameters in a lab. m.reover, the transmission, reflection, and absorption properties of the weak probe light through the slab were also discussed in detail.

关键词： optical bistability optical multistability quantum well nanostructure