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Improved double-gate armchair silicene nanoribbon field-effect-transistor at large transport bandgap

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Chinese Physics B 2016年第1期25卷 809-816页

作者： Mohsen Mahmoudi zahra Ahangari Morteza Fathipour Department of Electrical and Computer Engineering University of Tehran Young Researchers and Elite Club Yadegar-e-Imam Khomeini (RAH) Shahre-Rey Branch Islamic Azad University

The electrical characteristics of a double-gate armchair silicene nanoribbon field-effect-transistor （DG ASiNR FET） are thoroughly investigated by using a ballistic quantum transport model based on non-equilibrium Green＇s function （NEGF） approach self-consistently coupled with a three-dimensional （3D） Poisson equation. We evaluate the influence of variation in uniaxial tensile strain, ribbon temperature and oxide thickness on the on-off current ratio, subthreshold swing, transconductance and the delay time of a 12-nm-length ultranarrow ASiNR FET. A novel two-parameter strain mag- nitude and temperature-dependent model is presented for designing an optimized device possessing balanced amelioration of all the electrical parameters. We demonstrate that employing HfO2 as the gate insulator can be a favorable choice and simultaneous use of it with proper combination of temperature and strain magnitude can achieve better device performance. Furthermore, a general model power （GMP） is derived which explicitly provides the electron effective mass as a function of the bandgap of a hydrogen passivated ASiNR under strain.

关键词： silicene double-gate field-effect-transistor non-equilibrium Green's function tight binding

High photocatalytic efficiency of spouting reactor compared with fluidized bed with top irradiation source

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Particuology 2017年第4期15卷 123-128页

作者： Hadi Mansoubi zahra Mansourpour Shohreh Fatemi School of Chemical Engineering College of Engineering University of Tehran Tehran lran

The removal of volatile organic compounds by photocatalytic degradation is one of the safest and most effective ways of removing pollutants from the air. This process is highly affected by the type of reactor, light exposure, and hydrodynamics. For scale up purposes, continuous reactors with high capacity are required for treating large amounts of feedstock. In this work, two types of reactors based on different hydrodynamics, fluidized and spouted reactors, were designed to work under light irradiation inside the reactor. The efficiency of the reactors for volatile organic compound removal from high flow rates of air under Hg lamp irradiation using N-F-TiO2 photocatalyst was investigated. The performance of the fluidized bed and spouted bed were evaluated and compared at the same weight hourly space velocity of feed stream through the reactor. The results revealed that 80% of the initial acetaldehyde was removed in the fluidized bed after about 200 min, while in the spouted bed the acetaldehyde was totally removed after about 120 min.

关键词： Spouted bed reactor Photocatalyst powder VOC removal High efficiency Fluidized bed reactor N-F TiO2

Effect of Ni loadings on the activity and coke formation of MgO-modified Ni/Al_2O_3 nanocatalyst in dry reforming of methane

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Journal of Energy Chemistry 2014年第5期23卷 633-638页

作者： zahra Alipour Mehran Rezaei Fereshteh Meshkani Catalyst and Advanced Materials Research Laboratory Chemical Engineering Department Faculty of Engineering University of Kashan Institute of Nanoscience and Nanotechnology University of Kashan

MgO-modified Ni/Al2O3 catalysts with different Ni loadings were prepared and employed in dry reforming of methane （DRM）. The effect of Ni loadings on the activity and coke formation of Ni/MgO-A1203 catalysts were investigated. The synthesized catalysts were characterized by XRD, N2 adsorption-desorption, SEM, TPO and TPR techniques. The obtained results showed that increasing nickel loading decreased the BET surface area and increased the catalytic activity and amount of deposited carbon. In addition, the effect of gas hourly space velocity （GHSV） and feed ratio were studied.

关键词： nickel catalyst MgO modifier syngas dry reforming coke formation

High efficiency visible-light-driven Fe_2O_3-xS_x/S-doped g-C_3N_4 heterojunction photocatalysts: Direct Z-scheme mechanism

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Journal of Materials Science & Technology 2018年第9期34卷 1511-1525页

作者： Milad Jourshabani zahra Shariatinia Alireza Badiei Department of Chemistry Amirkabir University of Technology (Tehran Polytechnic) School of Chemistry College of Science University of Tehran Nanobiomedicine Center of Excellence Nanoscience and Nanotechnology Research Center University of Tehran

Several nanoporous Fe2 O3-xSx/S-doped g-C3 N4（CNS） Z-scheme hybrid heterojuctions have been successfully synthesized by one-pot in situ growth of the Fe2O3-xSx particles on the surface of CNS. The characterization results show that S-doping in the g-C3 N4 backbone can greatly enhance the charge mobility and visible light harvesting capability. In addition, porous morphology of hybrid composite provides available open pores for guest molecules and also improves light absorbing property due to existence of multiple scattering effects. More importantly, the Fe2 O3-xSx nanoparticles formed intimate heterojunction with CNS and developed the efficient charge transfer by extending interfacial interactions occurred at the interfaces of both components. It has been found that the Fe2 O3-xSx/CNS composites have an enhanced photocatalytic activity under visible light irradiation compared with isolated Fe2 O3 and CNS components toward the photocatalytic degradation of methylene blue（MB）. The optimal loaded Fe2 O3-xSx value obtained is equal to 6.6 wt% that provided 82% MB photodegradation after 150 min with a reaction rate constant of 0.0092 min（-1） which was faster than those of the pure Fe2 O3（0.0016 min（-1））and CNS（0.0044 min（-1）） under the optimized operating variables acquired by the response surface methodology. The specific surface area and the pore volume of Fe2 O3（6.6）/CNS hybrid are 33.5 m2/g and0.195 cm3/g, which are nearly 3.8 and 7.5 times greater compared with those of the CNS, respectively. The TEM image of Fe2 O3（6.6）/CNS nanocomposite exhibits a nanoporous morphology with abundant uniform pore sizes of around 25 nm. Using the Mott-Schottky plot, the conduction and valence bands of the CNS are measured（at pH = 7） equal to-1.07 and 1.48 V versus normal hydrogen electrode（NHE）, *** tests prove that ·OH-and ·O2-radicals are major active species in the photocatalytic *** has been established that formation of the Z-scheme Fe2 O3（6.6）/CNS he

关键词： Visible light irradiation Nanophotocatalyst in situ S-doping Z-scheme heterojunction Response surface methodology(RSM)

Review of electrodeposition methods for the preparation of high-entropy alloys

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International Journal of Minerals,Metallurgy and Materials 2022年第9期29卷 1683-1696页

作者： zahra Shojaei Gholam Reza Khayati Esmaeel Darezereshki Department of Materials Science and Engineering Shahid Bahonar University of KermanKerman 76135-133Iran

High-entropy alloys(HEAs)are suitable for engineering applications requiring excellent mechanical,corrosion,thermal,and magnetic *** the last decade,electrodeposition has emerged as a promising synthesis technique for *** has focused on the influence of procedure parameters on the deposition of different HEA layers and the effect of their microstructure on their corrosion and magnetic *** review of current literature provides comprehensive information on HEAs and the use of direct and pulse electrodeposition as a synthesis technique for these *** review also addresses the research gaps on HEA production via electrodeposition,such as using other ceramic particles instead of graphene oxide in composite structures based on HEAs.

关键词： high-entropy alloy electrodeposition corrosion resistance magnetic properties

Synthesis of mesoporous silica/iron oxide nanocomposites and application of optimum sample as adsorbent in removal of heavy metals

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Rare Metals 2017年第12期36卷 942-950页

作者： Shirin Kalantari Mardali Yousefpour zahra Taherian Faculty of Materials and Metallurgical Engineering Semnan University Semnan 35131-19111 Iran

In this study, mesoporous silica/iron oxide nanocomposite(MCM-FeO) was synthesized via hydrothermal technique. The chemical synthesis of MCM-FeOnanocomposite was achieved at 18 h. The effect of concentration of tetraethylorthosilicate(TEOS) on nanocomposites properties was studied during synthesis process. For this purpose, 0.5, 1.5, 2.5, 3.5, and 4.5 ml tetraethylorthosilicate(TEOS) were selected, respectively. The textural properties and microstructure of the nanocomposites were characterized by X-ray diffraction(XRD), Fourier transform infrared spectroscopy(FTIR), field emission scanning electron microscopy(FESEM), Nadsorption-desorption, and vibrating sample magnetometer(VSM) analysis. Results show that the nanocomposite with tetraethylorthosilicate(TEOS)/cetyltrimethylammonium bromide(CTAB) ratio of 5 exhibits large surface areas(461.19 m~2·g). Furthermore, this nanocomposite shows superparamagnetic behavior under external magnetic field compared to other samples. Moreover, results of removal of metal ions indicate that adsorption of Ni(II), Cd(II), Cr(III),Zn(II), and Pb(II) ions on the surface of adsorbent(nanocomposite) increases with the increase in solution pH, contact time,and adsorbent dosage. Furthermore, the maximum removal rates of heavy metals ions reach 53.0 %, 79.0 %, 61.0 %,89.0 %, and 99.5 % at pH of 5, time of 50 min, and the weight of adsorbent of 0.16 with 2.5 ml TEOS, respectively.

关键词： Interfaces Adsorption Nanocomposite Amorphous materials Oxides

The non-isothermal gravimetric method for study the thermal decomposition kinetic of HNBB and HNS explosives

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Defence Technology（防务技术） 2020年第1期16卷 251-256页

作者： Hamid Reza Pouretedal Sajjad Damiri zahra Bighamian Faculty of Applied Chemistry Malek-ashtar University of TechnologyShahin-ShahrIran

The hexanitrostilben(HNS) is a thermally stable explosive that can be prepared from hexanitrobibenzyl(HNBB).Therefore,the investigation of thermal stability of HNBB can be important in the yield of preparation of *** decomposition kinetic of HNBB and HNS are studied by non-isothermal gravimetric *** TG/DTG curves in non-isothermal method are obtained in range of 25℃-400℃at heating rates of 3℃/min,5℃/min,8℃/min,10℃/min and 12℃/*** data of weighttemperature are used for calculation of activation energy(E_a) of thermal decomposition reactions by methods of Ozawa,Kissinger,Ozawa-Flynn-Wall(OFW) and Kissinger-Akahira-Sunose(KAS) as modelfree methods and Strink's equation as model-fitting *** compensation effect is used for prediction of mechanism and determination of pre-exponential factor(InA) of the decomposition reaction.A reduction 60 kj/mol for the average of activation energy of thermal decomposition reaction of HNBB is obtained versus *** result shows the lower thermal stability of HNBB in comparison to HNS,The Avrami equation(A_(3/2)) with function f(α)=3/2(1-α)[-In(1-α)]^(1/3) indicates the predicted mechanism for thermal decomposition reaction both explosives.

关键词： HNS HNBB Decomposition Thermal Kinetic

Fabrication and Characterization of Willemite Scaffolds Using Corn Stalk as a Novel Bio Template for Bone Tissue Engineering Applications

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Journal of Bionic Engineering 2023年第1期20卷 16-29页

作者： zahra Yahay Seyed Mehdi Mirhadi Fariborz Tavangarian Department of Cellular Biotechnology Cell Science Research CenterRoyan Institute for BiotechnologyACECRIsfahan81593-58686Iran Department of Materials Engineering Shahreza BranchIslamic Azad UniversityShahrezaIsfahan86145-311Iran Mechanical Engineering Program School of ScienceEngineering and TechnologyPennsylvania State UniversityHarrisburgMiddletownPA17057USA

In this paper,we used Corn Stalk(CS)as a renewable and economical bio template to fabricate willemite scaffolds with the potential application in skull bone *** was used as a sacrificial template to synthesize the *** scaffolds with the chemical formula of Zn2SiO4 and pore size in the range of 3 to 10µm could be successfully synthesized by soaking CS in the willemite solution for 24 h and sintering at 950°C for 5 *** porosity of the samples was controlled by the soaking time(between 12 and 48 h)in the willemite solution from 5 to 35%,*** properties of these scaffolds showed a good approximation with cranial bone *** addition,cytotoxicity assays(MTT)were performed on Human Bone Marrow Stromal cells(HBMSc)and A172 human glioblastoma cell lines by direct and indirect culture methods to estimate their toxicity for bone and nerve cells,*** Phosphatase(ALP)activity and DAPI/Phalloidin cell staining were also performed to investigate the efficiency of the scaffolds for bone tissue engineering *** results showed that the scaffolds had good biocompatibility with both HBMSC and A172 cells,noticeable improvement on ALP activity,and great apatite formation ability in Simulated Body Fluid(SBF).All the evidence ascertained that willemite scaffolds made by corn stalks could be a useful candidate for bone tissue engineering applications.

关键词： Corn stalk Bio template Bioactive ceramics-Scaffolds Bone tissue engineering

Catalyst free synthesis of fused pyrido[2,3-d]pyrimidines and pyrazolo[3,4-b]pyridines in water

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Chinese Chemical Letters 2012年第10期23卷 1149-1152页

作者： Abbas Rahmati zahra Khalesi Department of Chemistry University of IsfahanP.O.Box 8174673441 IsfahanIran

A one-pot, three-component condensation reaction of an aldehyde, benzoyl acetonitrile （3-oxo-3-phenylpropane nitrile） and 6- amino-1,3-dimethylpyrimidine-2,4（1H,3H）-dione or 3-methyl-l-phenyl-lH-pyrazol-5-amine in water to give fused pyrido[2,3- d]pyrimidines and pyrazolo[3,4-b]pyridines in high yields without any catalyst, is described.

关键词： Aminopyrazole Aqueous media 3-Methyl-l-phenyl-lH-pyrazol-5-amine Pyrazolo[3,4-b]pyridine