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MF-DFA Analysis of Turbulent Transport Measured by a Multipurpose Probe

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Chinese Physics Letters 2015年第10期32卷 76-79页

作者： Lafouti M ghoranneviss M Department of Physics Damavand Branch Islamic Azad University Damavand Iran Plasma Physics Research Center Science and Research Branch Islamic Azad University Tehran Iran

The effect of time of applied bias on the edge turbulent transport is analyzed by the multi-fractal detrend fluctu- ation analysis （MF-DFA） method in the IR-Tl tokamak. The generalized Hurst exponents and the multifractal spectrum are computed by this method. The MF-DFA method is applied to the fluctuation of gradient of float- ing potential time series collected by a multipurpose probe. Tile monofractality or multifractality of the time series can be detected by generalized exponent. The multifractal spectrum describes the singularity content of the process. The results show that with applying bias to the plasma at different times （t = 15 ms, 18ms and 22ms）, the degree of multifractality changes. It reaches the minimum when the bias is applied at t = 18 ms. The multifractality source of data is investigated by the surrogate method （phase randomization techniques）. The surrogate method can destroy the different types of correlations in all the sizes of fluctuations. The results show that the long-range correlation contributes more to multifractality than the fat tail distribution.

关键词： TURBULENCE MULTIFRACTALS RANDOMIZATION (Statistics) CORRELATION (Statistics) TIME series analysis

Bias Effects on the Reynolds Stress Using the Multi-Purpose Probe in IR-T1 Tokamak

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Chinese Physics Letters 2016年第1期33卷 88-91页

作者： M.Lafouti M.ghoranneviss Department of Physics Damavand BranchIslamic Azad University Plasma Physics Research Center Science and Research BranchIslamic Azad University

The effect of the positive bias on Reynolds stress （RS） and its effect on the radial turbulent transport at the edge plasma （r/a =0.9） and scrape-off layer （SOL） region of plasma in tokamak are investigated. The radial and poloidal electric fields （Sr, Ep） and ion saturation current （Is） are measured by multi-purpose probe （MPP）. This probe is fabricated and constructed for the first time in the IR-T1 tokamak. The most advantage of this probe is that the variations of Er and Ep can be measured in different radii at the single shot. Thus the information of different radii can be compared with high precision. The bias voltage is fixed at Vbias = 200 V and it has been applied with the limiter bias that is fixed in r/a = 0.9. Moreover, the phase difference between radial and poloidal electric fields, and temporal evolution of the RS .spectrum detected by MPP are calculated. RS magnitude on the edge （r/a = 0.9） is more than its value in the SOL （r/a = 1.02）. With the applied bias 200 V, ItS and the magnitude of the phase difference between Er and Ep are increased, while the radial turbulent transport is decreased simultaneously. Thus it can be concluded that RS affects radial turbulence. Temporal evolution of the RS spectrum shows that the frequency of RS is increased and reaches its highest value at r/a=0.9 in the presence of bias.

关键词： of is RS been in Bias Effects on the Reynolds Stress Using the Multi-Purpose Probe in IR-T1 Tokamak on IR

Surface Modification of Poly Vinyl Chloride (PVC) Using Low Pressure Argon and Oxygen Plasma

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Plasma Science and Technology 2010年第2期12卷 204-207页

作者： Mahmood ghoranneviss Sheila SHAHIDI Jakub WIENER Plasma Physics Research Center Science and Research Branch Islamic Azad University Department of Textile Chemistry Faculty of Textile Technical University of Liberec

In this study, commercial poly vinyl chloride （PVC） films were treated by oxygen and argon plasmas in a cylindrical glass tube which was surrounded by a DC variable magnetic field, with different sample positions in the plasma reactor and also different exposure durations. Effects of the plasma treatment on the hydrophilic properties of the films were studied by mea- suring the water drop contact angle on the surface of the samples. The surface topography of the untreated and plasma treated films was analyzed and compared by atomic force microscopy （AFM）. The optical characteristic changes in treated samples were investigated using reflective spectrophotometry. Also, the chemical changes which appeared on the surface of the samples were investigated using Fourier transform infrared spectroscopy （FTIR）. The results show that the plasma treated PVC becomes more hydrophilic with an enhanced wettability. A sharp de- crease in the water contact angle may also be a consequence of the surface texturization. The aging effect on wettability of the samples was also investigated. The results show that the effect of oxygen plasma on the surface properties of the samples is more pronounced compared with that of argon plasma.

关键词： plasma surface modification poly vinyl chloride

Sterilization of Cotton Fabrics Using Plasma Treatment

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Plasma Science and Technology 2013年第10期15卷 1031-1033页

作者： S.SHAHIDI M.ghoranneviss Department of Textile Faculty of EngineeringIslamic Azad University Plasma Physics Research Center Science and Research BranchIslamic Azad University

Microbial contamination induces surface deformations and strength degradation of cotton fabrics by invading deeply into the fibers. In this study, the sterilization effects of low pressure plasmas on bacteria-inoculated cotton fabrics were investigated. Oxygen plasma treatment completely sterilized the cotton fabrics inoculated with various concentrations of staphylococcus aureus. Also, the influence of plasma treatment on physical properties of fabrics was examined. It was found that the plasma treatment did not affect ultimate tensile strength and surface morphology of the fabrics because it took advantage of relatively low plasma temperature.

关键词： sterilization fabri plasma treatment

Structure,morphology and electrical resistance of W_(x)N thin film synthesized by HFCVD method with various N_(2) contents

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Rare Metals 2020年第12期39卷 1440-1448页

作者： Somayeh Asgary Mohammad Reza Hantehzadeh Mahmood ghoranneviss Arash Boochani s.asgary m.r.hantehzadehm.ghoranneviss*.1.boochaniplasmaphysics research centerscience and research branchislamic azad universitytehran 14665-678iran department of physics kermanshah branchislamic azaduniversitykermanshah ***iran

Tungsten nitride(W_(x)N)thin films with good crystalline structure,high quality and relatively low resistivity were deposited by hot filament chemical vapor deposition(HFCVD)technique at different mixtures of N2 and Ar *** data demonstrate that different N_(2) contents in gas mixture strongly affect microstructure,phase formation,texture morphology and resistivity of the W_(x)N *** to X-ray diffraction(XRD)patterns,the growth of tungsten nitride films promotes δ-WN phase for lower N_(2) contents in gas *** higher N_(2) contents,a phase transition is observed in the tungsten nitride *** hexagonal δ-WN and cubic β-W_(2)N phases coexist,and WN phase approximately disappears with N_(2) contents in the gas mixture *** electron microscope(SEM)images for deposited films at lower N_(2) contents in gas mixture indicate a definite dense columnar *** electrical resistivity results exhibit a significant drop for the W_(x)N thin films with N_(2) contents in the mixed gas *** changes in N_(2) content in gas mixture are found to be responsible for variation in the film resistivity ***,the deposited tungsten nitride thin film at higher N_(2) contents in gas mixture has noncolumnar microstructure and lower resistivity,which may be used as a superior diffusion barrier.

关键词： Tungsten nitride Thin film HFCVD Electrical resistivity Diffusion barriers

Effect of Electron Irradiation on Polypropylene Films

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Plasma Science and Technology 2011年第2期13卷 194-196页

作者： Sheila SHAHIDI Jakub WIENER Mahmood ghoranneviss Abbas ANVARI Department of Textile Chemistry Faculty of Textile Technical University of Liberec Plasma Physics Research Center Science and Research Branch Islamic Azad University Departments of Physics Sharif University of Technology

Effects of both electron beam irradiation on the properties of polypropylene （PP） films and the irradiation on the different layers of a multilayer PP film are studied. A Fourier transform infrared spectroscope was used to investigate the chemical structure of the films. The results showed that the chemical properties of the first layer were improved, that is, more functional groups responsible for dye ability and hydrophilicity of the film were produced on its surface, while noticeable improvement was not detected on the surface of other layers. This was also confirmed by testing the dye ability of the layers. However, the results obtained by atomic force microscopy showed that the electron irradiation caused some topographical changes, not only on the surface of the first layer but also on the others.

关键词： polypropylene electron beam dye ability film

Influences of substrate temperature on microstructure and corrosion behavior of APS Ni_(50)Ti_(25)Al_(25) inter-metallic coating

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Chinese Physics B 2018年第2期27卷 607-612页

作者： Sh Khandanjou M ghoranneviss Sh Saviz M Reza Afshar Plasma Physics Research Center Science and Research Branch Islamic Azad University Department of Materials Engineering Science and Research Branch Islamic Azad University

In the present investigation, Ni_（50）Ti_（25）Al_（25）（at.%） mechanically alloyed powder is deposited on carbon steel *** the coating process, the substrate is heated to temperature ranging from room temperature to 400℃. The microstructure, porosity, microhardness, adhesion strength, and corrosion behavior of the coating are investigated at different substrate temperatures. Results show that coating porosity is lower on high temperature surface. Microhardness and adhesion strength of the deposition layer on the substrate without preheating have lower values than with preheating. The polarization test result shows that corrosion performance of the coating is dependent on micro cracks and porosities and the increasing of substrate temperature can improve the quality of coating and corrosion performance.

关键词： Ni50Ti25Al25 coating air plasma spray planetary ball milling inter-metallic compounds corrosion resistance

The Diffusion Coefficient Using Sawtooth Oscillation in IR-T1 Tokamak

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Chinese Physics Letters 2017年第8期34卷 101-103页

作者： N. Hasanvand S. Meshkani M. ghoranneviss Plasma Physics Research Center Science and Research Branch Islamic Azad University Tehran Iran

The investigation of runaway electrons is expanded by different methods. The aim of this study is to show sawtooth oscillations of hard x-ray emission and with the help of sawtooth oscillations to obtain radial diffusion coefficient and magnetic fluctuations. In the same way, the hard x-ray spectral evaluation is compared in several time intervals and it is shown that during discharge, the energy of the runaway electrons is less than 200？keV. Also, for typical plasmas, population of runaway electrons is measured at seven time intervals of 5ms and temporal evaluation of runaway electron mean energy. The sawtooth-like shape is observed in the hard x-ray range （10–1000？keV）. By the sawtooth oscillation method, the RE diffusion coefficient in radial transport in the IR-T1 plasma is Dr～0.5Dr～0.5m^2s^-1. The magnetic field fluctuation due to magnetic diffusion DmDm is given as br/Bt～10^-4.

关键词： RE The Diffusion Coefficient Using Sawtooth Oscillation in IR-T1 Tokamak IR

Investigations into the Anti-Felting Properties of Sputtered Wool Using Plasma Treatment

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Plasma Science and Technology 2013年第1期15卷 37-42页

作者： S. M. BORGHEI S. SHAHIDI M. ghoranneviss Z. ABDOLAHI Department of Physics Karaj Branch Islamic Azad University Department of Textiles Faculty of Engineering Arak Branch Islamic Azad University Plasma Physics Research Center Science and Research Branch Islamic Azad University

In this research the effects of mordant and plasma sputtering treatments on the crystallinity and morphological properties of wool fabrics were investigated. The felting behavior of the treated samples was also studied. We used madder as a natural dye and copper sulfate as a metal mordant. We also used copper as the electrode material in a DC magnetron plasma sputtering device. The anti-felting properties of the wool samples before and after dying was studied, and it was shown that the shrink resistance and anti-felting behavior of the wool had been significantly improved by the plasma sputtering treatment. In addition, the percentage of crystallinity and the size of the crystals were investigated using an X-ray diffractometer, and a scanning electron microscope was used for morphological analysis. The amount of copper particles on the surface of the mordanted and sputtered fabrics was studied using the energy dispersive X- ray （EDX） method, and the hydrophobic properties of the samples were examined using the water drop test. The results show that with plasma sputtering treatment, the hydrophobic properties of the surface of wool become super hydrophobic.

关键词： anti-felting wool plasma mordant sputtering