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Journal of Materials science & Technology 2011年第8期27卷 735-740页

作者： s. Ahmadi H.R. shahverdi s.s. saremi Faculty of Engineering Department of Materials Science Tarbiat Modares University

Crystallization kinetics of Fe55-xCrzsMo7B10C4Nbx（x= 0, 3） bulk amorphous alloys were analyzed using X-ray diffraction and differential scanning; calorimetric （DsC） tests. In practice, crystallization and growth mechanism were evaluated using DsC tests at four different heating rates （10, 20, 30, and 40 K/rain） and kinetic models. Two-step crystallization behavior was observed when Fe55Cr18MOTB16C4 and Fe52Cr18MoTB16C4Nb3 bulk amorphous alloys were annealed, where Fe36Cr12M010 phase was crystallized in the first step of crystallization. Results show that Fe36Cr12Mo10 and Fe3C phases were crystallized in the structures of the alloys after further annealing： process. Activation energy for the crystallization of Fe36Cr12Mozo phase was measured to be 543 kJ/mol in Fe52Cr18MoTB16C4Nb3 alloy and 375 kJ/mol for Fe55Cr18Mo7B16C4 alloy according to Kissinger-starink model. Moreover, a two-dimensiona nucleation rate was found in Fe52Cr18Mo7B16C4Nb3 diffusion controlled growth mechanism with decreasing alloy whereas a three-dimensional diffusion controlled growth mechanism with decreasing nucleation rate was found in crystallization of Fe36Crz2Mo10 phase during annealing of Fe55Cr18MoTB16C4 alloy. TEM （transmission electron microscopy） observations reveal that crystalline Fe36Cr12M010 phase nucleated in the structures of the alloys in an average size of 10 nm with completely mottled morphology.

关键词： Avrami exponent Crystallization Kinetic models Growth mechanisms Bulk amorphous alloys

Effect of Metal Contact and Rapid Thermal Annealing on Electrical Characteristics of Graphene Matrix

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Chinese Physics Letters 2017年第10期34卷 65-69页

作者： s, Fahad M. Ali s. Ahmed s. Khan s. Alam s. Akhtar Advanced Electronics Laboratories International Islamic University Islamabad Pakistan Department of Physics Federal Urdu University of Arts Sciences & Technology Karachi Pakistan

Development of graphene field effect transistors （GFETs） faces a serious challenge of graphene interface to the dielectric material. A single layer of intrinsic graphene has an average sheet resistance of the order of 1-5 kΩ/□. The intrinsic nature of graphene leads to higher contact resistance yielding into the outstanding properties of the material. We design a graphene matrix with minimized sheet resistance of 0.185 kΩ/□ with Ag contacts. The developed matrices on silicon substrates provide a variety of transistor design options for subsequent fabrication. The graphene layer is developed over 400 nm nickel in such a way as to analyze hypersensitive electrical properties of the interface for exfoliation. This work identifies potential of the design in the applicability of few-layer GFETs with less process steps with the help of analyzing the effect of metal contact and post-process anneMing on its electrical fabrication.

关键词： Effect of Metal Contact and Rapid Thermal Annealing on Electrical Characteristics of Graphene Matrix

Application of integrated simulation environment sIEMNED to the analysis of the MEPHIsT-0 tokamak operation

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Plasma science and Technology 2023年第3期25卷 222-233页

作者： D Yu sYCHUGOV s Yu sOLOVIEV A s ZHILKIN A V MELNIKOV s A KRAT Faculty of Computational Mathematics and Cybernetics Lomonosov Moscow State University National Research Centre Kurchatov Institute National Research Nuclear University Moscow Engineering Physics Institute National University Moscow Institute of Physics and Technology

This paper presents the results of numerical simulation of plasma equilibrium and stability in the MEPHIsT-0 tokamak with sIEMNED software and comparison of simulation results with *** determined characteristics of the vacuum chamber show that it significantly affects the entire *** various scenarios of the inductor operation,a comparison of experimental data and simulated currents and magnetic fields induced in the chamber was carried *** steady-state tokamak operation,a numerical study of equilibrium plasma configurations was carried out depending on the currents in the poloidal magnetic field coils and plasma *** vertical plasma instability was *** limiting values of plasma ellipticity preventing the vertical plasma instability were numerically *** simulations show that plasma equilibrium is supported by induced *** was shown numerically that magnetic configuration with‘zero of higher order’were obtained before the plasma shot,suggesting consistency between the simulation results and observations.

关键词： mathematical modelling tokamak installation MEPHIsT-0

Effect of Under Connected Plates on the Hydrodynamic Efficiency of the Floating Breakwater

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China Ocean Engineering 2014年第3期28卷 349-362页

作者： A.s.Koraim O.s.Rageh Water and Water structure Engineering Department Faculty of EngineeringZagazig University Irrigation and Hydraulics Department Faculty of Engineering El-Mansoura University

In this paper, the hydrodynamic efficiency of a floating breakwater system is experimentally studied by use of physical models. Regular waves with wide ranges of wave heights and periods are tested. The efficiency of the breakwater is presented as a function of the wave transmission, reflection, and energy dissipation coefficients. Different parameters affecting the breakwater efficiency are investigated, e.g. the number of the under connected vertical plates, the length of the mooring wire, and the wave length. It is found that, the transmission coefficient kt decreases with the increase of the relative breakwater width B/L, the number of plates n and the relative wire length l/h, while the reflection coefficient kr takes the opposite trend. Therefore, it is possible to achieve kt values smaller than 0.25 and kr values larger than 0.80 when B/L is larger than 0.25 for the case of l/h-1.5 and n=4. In addition, empirical equations used for estimating the transmission and reflection coefficients are developed by using the dimensionless analysis, regression analysis and measured data and verified by different theoretical and experimental results.

关键词： floating breakwaters vertical plates regular waves transmission reflection energy dissipation

Effect of temperature on pull-in voltage and nonlinear vibration behavior of nanoplate-based NEMs under hydrostatic and electrostatic actuations

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Acta Mechanica solida sinica 2017年第2期30卷 174-189页

作者： Farzad Ebrahimi s.H.s.Hosseini Department of Mechanical Engineering Faculty of Engineering Imam Khomeini International University qazvinIran

This paper deals with the study of the temperature effect on the nonlinear vibration behavior of nanoplate-based nano electromechanical systems（NEMs） subjected to hydrostatic and electrostatic actuations. Using Eringen＇s nonlocal elasticity and Gurtin–Murdoch theory, the nonlocal plate model is derived through Hamilton＇s principle. The governing equation which is extremely nonlinear due to the geometrical nonlinearity and electrostatic attraction forces is solved numerically using the differential quadrature method（DQM）. The accuracy of the present method is veriied by comparing the obtained results with the experimental data and those in the literature and very good agreement is obtained. Finally a comprehensive study is carried out to determine the inluence of temperature on the nonlinear vibration characteristics of NEMs made of two different materials including aluminum（Al）and silicon（si） and some conclusions are drawn.

关键词： small scale effect Nano electromechanical system Nonlinear vibration Temperature effect Pull-in voltage

Macroscopic studies on the Properties of the Anodic Oxide Films on Titanium

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Journal of Materials science & Technology 1998年第3期14卷 241-246页

作者： Mahdy, G.A. Mahmoud, s.s. Chemistry Dept. Faculty of Science Helwan University Helwan Cairo Egypt Chemistry Dept. University College for Women Ain-Shams University Helopolis Cairo Egypt

The effect of fluoride ions on the formation and dissolution behaviour of anodic oxide films on Ti has been investigated in acidic fluoride media (pH=1) using impedance and galvanostatic techniques. A5 the fluoride ion concentration and temperature increase the rate of oxide film formation decreases while the dissolution process increases. oxide film formed at high tem-perature and formation voltage was found to contain more defect sites in the film than that formed at a lower one. Activation energies are calculated during the oxide film formation and dissolution and found to be 20.76 and 28.72 kJ/mol, respectively. Formation rate and reciprocal capacitance data are reported as a function of polarizing current density. Values are recorded for the electrolytic parameters A and B. Potentiostatic curves are derived from the galvanostatic results.

关键词： Figure Macroscopic studies on the Properties of the Anodic Oxide Films on Titanium

Effect of substrate and Annealing Temperatures on Mechanical Properties of Ti-rich NiTi Films

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Journal of Materials science & Technology 2010年第11期26卷 961-966页

作者： A.Kumar s.K.sharma s.Bysakh s.V.Kamat s.Mohan Defence Metallurgical Research Laboratory Department of Instrumentation Indian Institute of Science Central Glass and Ceramics Research Institute

The effect of substrate and annealing temperatures on mechanical properties of Ti-rich NiTi films deposited on si （100） substrates by DC magnetron sputtering was studied by *** films were deposited at two substrate temperatures viz.300 and 400 ℃.NiTi films deposited at 300 ℃ were annealed for 4 h at four different temperatures,i.e.300,400,500 and 600 C whereas films deposited at 400 ℃ were annealed for 4 h at three different temperatures,i.e.400,500 and 600 ℃.The elastic modulus and hardness of the films were found to be the same in the as-deposited as well as annealed conditions for both substrate *** a given substrate temperature,the hardness and elastic modulus were found to remain unchanged as long as the films were ***,both elastic modulus and hardness showed an increase with increasing annealing temperature as the films become *** results were explained on the basis of the change in microstructure of the film with change in annealing temperature.

关键词： NiTi thin film Annealing Nanoindentation

Aerodynamic characteristics of unsymmetrical aerofoil at various turbulence intensities

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Chinese Journal of Aeronautics 2019年第11期32卷 2395-2407页

作者： s.ARUNVINTHAN s.NADARAJA PILLAI Turbulence & Flow Control Lab School of Mechanical Engineering SASTRA Deemed University

A series of wind tunnel tests were performed to investigate the effect of turbulent inflows on the aerodynamic characteristics of the unsymmetrical airfoil at various turbulence intensities and Reynolds number. To assess the aerodynamic characteristics, surface pressure measurements were made over the unsymmetrical airfoil surface by using a simultaneous pressure scanner MPs4264 of scanivalve make. self-generated passive grids made of parallel arrays of round bars were placed at four different locations to generate various Turbulence Intensities(TI) in the wind tunnel. The location of the passive grid has been normalized in terms of considering the distance between the entry of the test section and the leading edge of the model. Based on the wind tunnel results, by comparing the baseline without grid low turbulence case TI = 0.51% with other turbulence generated cases like TI = 4.68%, 4.73%, 6.04% and 8.46% at different Reynolds number, it is found that the coefficient of lift increases with the increase in the turbulence intensity. Results also reveal that the flow featuring turbulence can effectively delay the stall characteristics of an airfoil by attaching the flow over the airfoil for an extended region. Additionally, attempts were made to understand the influence of turbulence on the aerodynamic hysteresis.

关键词： Aerodynamic efficiency Aerodynamic hysteresis Passive grid simultaneous pressure distribution Turbulence intensity

An in situ monitoring method for PECVD process equipment condition

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Plasma science and Technology 2019年第6期21卷 15-22页

作者： G KANG s AN K KIM s HONG Department of Electronic Engineering Myongji University Yongin 17058 Republic of Korea

A key to successful consistent plasma processing is maintaining a consistent process chamber condition over a certain production *** alleviate the concern,in situ process monitoring sensors are employed to investigate the plasma chamber conditions of both the deposition step with direct plasma and the cleaning step with a remote plasma *** situ sensors are optical emission spectroscopy (OEs),optical plasma monitoring sensors (OPMs),voltage current probes (Ⅵ-probes),and self-plasma OEs (sP-OEs).During the deposition,we perform the monitoring of a plasma condition associated with the applied RF power via OEs,OPMs,and a Ⅵ-*** the chamber cleaning step using a remote plasma system does not allow plasma monitoring through the sidewall because the plasma is not formed in the process chamber,thus we employed sP-OEs to monitor the by-product gas chemistry during the chamber cleaning process *** monitoring results with some useful applications,such as arc detection,part failure detection,and cleaning process chemistry analysis,are presented in this *** use of in situ sensors with proper combination can help to understand the plasma process better,to achieve more precise control of plasma processing.

关键词： in situ monitoring sensor advanced equipment control

Nonlinear parametric interactions in ion-implanted semiconductor plasmas having strain-dependent dielectric constants

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Chinese Physics B 2017年第1期26卷 304-309页

作者： N Yadav s Ghosh P s Malviya school of studies in Physics Vikram University Ujjain 465010 India Department of Physics Govt. J.N.S. Post Graduate College Shujalpur 465333 India

We report nonlinear parametric interactions using a hydrodynamic model of ion-implanted semiconductor plasmas having strain-dependent dielectric constants（sDDC）. High-dielectric-constant materials are technologically important because of their nonlinear properties. We find that the third-order susceptibility varies in the range 10^-14--10^-12m^2·V^-2 for ion-implanted semiconductor plasmas, which is in good agreement with previous results. It is found that the presence of sDDC in ion-implanted semiconductor plasma modifies the characteristic properties of the material.

关键词： nonlinear parametric interactions ion-implanted semiconductor plasmas strain-dependent dielectric constant