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    Construction of Pt nanoparticle-decorated graphene nanosheets and carbon nanospheres nanocomposite-modified electrodes: Application to ultrasensitive electrochemical determination of cefepime

    , Article RSC Advances ; Volume 4, Issue 15 , 2014 , Pages 7786-7794 ; ISSN: 20462069 Shahrokhian, S ; Hosseini Nassab, N ; Ghalkhani, M ; Sharif University of Technology
    Abstract
    A novel ultrasensitive modified electrode was fabricated with a graphene nanosheets and carbon nanospheres (GNS-CNS)-based nanocomposite film as a powerful platform. Pt nanoparticles (PtNPs) were simply electrodeposited onto the GNS-CNS-coated glassy carbon electrode creating a PtNPs/GNS-CNS hybrid nanocomposite modified electrode. Scanning electron microscopy, energy dispersive X-ray spectroscopy and linear sweep voltammetry (LSV) techniques were used for the characterization of the prepared modified electrode. The results of investigation of electrochemical response characteristics of cefepime (CP) revealed a considerable improvement in the oxidation peak current of CP on PtNPs/GNS-CNS/GCE... 

    Growth and characterization of TixNi1-x shape memory thin films using simultaneous sputter deposition from separate elemental targets

    , Article Thin Solid Films ; Volume 491, Issue 1-2 , 2005 , Pages 190-196 ; 00406090 (ISSN) Sanjabi, S ; Sadrnezhaad, S. K ; Yates, K. A ; Barber, Z. H ; Sharif University of Technology
    2005
    Abstract
    The fabrication of TixNi1-x shape memory films using simultaneous magnetron sputtering from two separate, elemental targets was investigated. The films were deposited at room temperature and then annealed at 500 °C to achieve the shape memory effect. The influence of sputtering parameters such as power ratio to the targets (to control the composition) and Ar gas pressure (to control the film structure) were studied. It was found that the Ar gas pressure had a critical influence on the shape memory effect of the films. Characterization of the films was carried out by energy dispersive X-ray spectroscopy in a scanning electron microscope (to measure the film composition and uniformity), in... 

    Designing of CK45 carbon steel and aisi 304 stainless steel dissimilar welds

    , Article Materials Research ; Vol. 17, issue. 1 , Oct , 2014 , p. 106-114 ; 15161439 Pouraliakbar, H ; Hamedi, M ; Kokabi, A. H ; Nazari, A ; Sharif University of Technology
    Abstract
    Gas tungsten arc welding of CK45 and AISI304 stainless steel was performed through preparation of different types of samples using ER308L and ERNi-1 wires. Welded samples were studied by different techniques including optical metallography, scanning electron microscopy equipped with energy dispersive X-ray spectroscopy (SEM-EDS), X-ray diffraction, hardness measurements and impact test. It was observed that in the buttered specimen, the structure of the weld metal was completely austenitic while the microstructure of unbuttered sample was duplex ferritic-austenitic. M23C6-type carbides were observed within the weld metal of both as-weld specimen types. Effects of different post-weld heat... 

    Morphology, rheology and mechanical properties of polypropylene/ethylene-octene copolymer/clay nanocomposites: Effects of the compatibilizer

    , Article Composites Science and Technology ; Volume 72, Issue 14 , 2012 , Pages 1697-1704 ; 02663538 (ISSN) Bagheri Kazemabad, S ; Fox, D ; Chen, Y ; Geever, L. M ; Khavandi, A ; Bagheri, R ; Higginbotham, C. L ; Zhang, H ; Chen, B ; Sharif University of Technology
    Elsevier  2012
    Abstract
    The objective of this study was to investigate the effects of two compatibilizers, namely maleated polypropylene (PP-g-MA) and maleic anhydride grafted poly (ethylene-co-octene) (EOC-g-MA), on the morphology and thus properties of ternary nanocomposites of polypropylene (PP)/ethylene-octene copolymer (EOC)/clay nanocomposite. In this regard the nanocomposites and their neat polymer blend counterparts were processed twice using a twin screw extruder. X-ray diffraction, transmission electron microscopy, Energy dispersive X-ray spectroscopy, and scanning electron microscopy were utilized to characterize nanostructure and microstructure besides mechanical and rheological behaviors of the... 

    Effects of different operating parameters on the particle size of silver chloride nanoparticles prepared in a spinning disk reactor

    , Article Applied Physics A: Materials Science and Processing ; Volume 120, Issue 1 , July , 2015 , Pages 105-113 ; 09478396 (ISSN) Dabir, H ; Davarpanah, M ; Ahmadpour, A ; Sharif University of Technology
    Springer Verlag  2015
    Abstract
    The aim of this research was to present an experimental method for large-scale production of silver chloride nanoparticles using spinning disk reactor. Silver nitrate and sodium chloride were used as the reactants, and the protecting agent was gelatin. The experiments were carried out in a continuous mode by injecting the reactants onto the surface of the spinning disk, where a chemical precipitation reaction took place to form AgCl particles. The effects of various operating variables, including supersaturation, disk rotational speed, reactants flow rate, disk diameter, and excess ions, on the particle size of products were investigated. In addition, the AgCl nanoparticles were... 

    Hydrogen failure sensitivity of A516-Gr70 and API 5L-X70 steels in sour environments

    , Article Anti-Corrosion Methods and Materials ; Volume 62, Issue 5 , 2015 , Pages 294-300 ; 00035599 (ISSN) Taheri, H ; Dolati, A ; Beidokhti, B ; Sharif University of Technology
    Emerald Group Publishing Ltd  2015
    Abstract
    Purpose – This paper aims to clarify the corrosion behavior of two famous structural steels in sour environment. These steels have a vast application in oil and gas industries. The study aims to find the effect of different concentrations of sour solution on the origin of crack in these steels. Design/methodology/approach – After preparation of specimens, different sour solutions were made using the synthetic brine (according to National Association of Corrosion Engineers [NACE], Technical Committee Report 1D182) and various amounts of Na2S.9H2O and CH3COOH. The polarization test was done by Potansiostat apparatus model Zahner-IM6 at two temperatures, 25°C... 

    Spark plasma sintering of a multilayer thermal barrier coating on Inconel 738 superalloy: Microstructural development and hot corrosion behavior

    , Article Ceramics International ; Volume 42, Issue 2 , 2016 , Pages 2770-2779 ; 02728842 (ISSN) Pak Seresht, A. H ; Javadi, A. H ; Bahrami, M ; Khodabakhshi, F ; Simchi, A ; Sharif University of Technology
    Elsevier Ltd 
    Abstract
    In the present work, spark plasma sintering (SPS) process was employed to prepare a nanostructured yttria-stabilized zirconia (8YSZ) coating on a nickel-based superalloy (INCONEL 738) with functionally graded structure. A stack layer of INCONEL 738/NiCrAlY powder/Al foil/NiCrAlY+YSZ powder/YSZ powder was SPSed in a graphite die at an applied pressure of 40 MPa under an vacuum atmosphere (8 Pa). The sintering temperature was ∼1040 °C. For comparison purpose, the air plasma spray (APS) technique was employed to prepare the thermal barrier coating (TBC). Microstructural studies by scanning electron microscopy showed that the SPSed coating was sound and free of interfacial cracks and large... 

    Copper immobilized onto polymer-coated magnetic nanoparticles as recoverable catalyst for 'click' reaction

    , Article Applied Organometallic Chemistry ; 2016 ; 02682605 (ISSN) Banan, A ; Bayat, A ; Valizadeh, H ; Sharif University of Technology
    John Wiley and Sons Ltd  2016
    Abstract
    Copper supported on polymer-coated magnetic nanoparticles was designed and synthesized as a separable heterogeneous catalyst. The catalyst was fully characterized using several techniques such as Fourier transform infrared and energy-dispersive X-ray spectroscopies, scanning and transmission electron microscopies, X-ray diffraction, vibrating sample magnetometry, thermogravimetric analysis and inductively coupled plasma atomic emission spectrometry. All results showed that copper was successfully supported on the polymer-coated magnetic nanoparticles. Also, results showed that the synthesized material can be used as an efficient catalyst for the preparation of a series of 1,4-disubstituted... 

    Deposition of metallic molybdenum thin films on 304L steel substrate by SUT-PF

    , Article Surface and Coatings Technology ; 2016 ; 02578972 (ISSN) Hosseinzadeh, A ; Nazmabadi, M ; Vosoughi, N ; Sharif University of Technology
    Elsevier B. V 
    Abstract
    The present research work aims to employ plasma focus in order to deposit molybdenum (Mo) on the 304 stainless steel substrate. The processing parameters were shot numbers as well as the distance of substrate from the anode tip. Stereo, atom force microscopy (AFM) and field emission-scanning electron microscopy (FE-SEM) equipped with energy dispersive X-ray spectroscopy (EDS) were used to study the deposited coatings. Microhardness measurements were also performed on the coatings. Results indicated that the plasma focus can be successfully applied to deposit Mo anode on the stainless steel substrate. The coatings contained discrete pores with sizes varying by processing parameters. The... 

    Ugi four-component assembly process: An efficient approach for one-pot multifunctionalization of nanographene oxide in water and its application in lipase immobilization

    , Article Chemistry of Materials ; Volume 28, Issue 9 , 2016 , Pages 3004-3016 ; 08974756 (ISSN) Rezaei, A ; Akhavan, O ; Hashemi, E ; Shamsara, M ; Sharif University of Technology
    American Chemical Society  2016
    Abstract
    Graphene-based materials are revealing the leading edge of advanced technology for their exceptional physical and chemical properties. Chemical manipulation on graphene surface to tailor its unique properties and modify atomic structures is being actively pursued. Therefore, the discovery of robust and general protocols to anchor active functionality on graphene basal plane is still of great interest. Multicomponent reactions promise an enormous level of interest due to addressing both diversity and complexity in combinatorial synthesis, in which more than two starting compounds react to form a product derived from entire inputs. In this article, we present the first covalent... 

    Investigation on corrosion stratigraphy and morphology in some iron age bronze alloys vessels by OM, XRD and SEM–EDS methods

    , Article Applied Physics A: Materials Science and Processing ; Volume 122, Issue 4 , 2016 ; 09478396 (ISSN) Oudbashi, O ; Hasanpour, A ; Davami, P ; Sharif University of Technology
    Abstract
    The recently study of the corrosion in some bronze artefacts from the Sangtarashan Iron Age site, western Iran, was established to identify corrosion morphology and mechanism in these objects. The corrosion layers in 22 samples were studied by optical microscopy, scanning electron microscopy–energy-dispersive X-ray spectroscopy and X-ray diffraction methods. The results showed that a thin corrosion crust has formed on the surface of bronzes with a triple-layer structure, including two internal and one external corrosion layers. The formation of these layers is due to copper leaching from the bronze surface. The internal corrosion part has been a compact, tin-rich corrosion/oxidation product... 

    Copper immobilized onto polymer-coated magnetic nanoparticles as recoverable catalyst for ‘click’ reaction

    , Article Applied Organometallic Chemistry ; Volume 31, Issue 5 , 2017 ; 02682605 (ISSN) Banan, A ; Bayat, A ; Valizadeh, H ; Sharif University of Technology
    Abstract
    Copper supported on polymer-coated magnetic nanoparticles was designed and synthesized as a separable heterogeneous catalyst. The catalyst was fully characterized using several techniques such as Fourier transform infrared and energy-dispersive X-ray spectroscopies, scanning and transmission electron microscopies, X-ray diffraction, vibrating sample magnetometry, thermogravimetric analysis and inductively coupled plasma atomic emission spectrometry. All results showed that copper was successfully supported on the polymer-coated magnetic nanoparticles. Also, results showed that the synthesized material can be used as an efficient catalyst for the preparation of a series of 1,4-disubstituted... 

    Structural and corrosion characterization of hydroxyapatite/zirconium nitride-coated AZ91 magnesium alloy by ion beam sputtering

    , Article Applied Surface Science ; Volume 401 , 2017 , Pages 172-180 ; 01694332 (ISSN) Kiahosseini, S. R ; Afshar, A ; Mojtahedzadeh Larijani, M ; Yousefpour, M ; Sharif University of Technology
    Abstract
    The adhesion of hydroxyapatite (HA) as a coating for the AZ91 magnesium alloy substrate can be improved by using the sputtering method and an intermediate layer, such as ZrN. In this study, HA coatings were applied on ZrN intermediate layers at a temperature of 300 °C for 180, 240, 300, 360, and 420 min by ion beam sputtering. A profilometer device was used to study the HA coating thickness, which changed from 2 μm for the 180-min deposition to 4.7 μm for 420-min deposition. The grazing incidence X-ray diffraction analysis method and the Williamson–Hall analysis were used for structural investigation. As the deposition time increased, the crystalline size increased from 50 nm to 690 nm.... 

    Cyclic oxidation characteristics of HVOF thermal-sprayed NiCoCrAlY and CoNiCrAlY coatings at 1000 °C

    , Article Journal of Alloys and Compounds ; Volume 746 , 25 May , 2018 , Pages 509-519 ; 09258388 (ISSN) Feizabadi, A ; Salehi Doolabi, M ; Sadrnezhaad, S. K ; Rezaei, M ; Sharif University of Technology
    Elsevier Ltd  2018
    Abstract
    Thermal-sprayed MCrAlY coatings have become widespread in various industries such as power plants, aeronautics, and oil and gas firms. High-temperature oxidation behavior of these coatings is therefore of significance. Spraying of two prevalent MCrAlY powders (NiCoCrAlY and CoNiCrAlY) on Hastelloy substrate by high velocity oxygen and fuel method and exposing them to 1000 °C air for resolving of their cyclic oxidation behavior are presented in this paper. The coatings were characterized by x-ray diffraction, scanning electron microscopy and energy-dispersive x-ray spectroscopy. The obtained oxidation kinetic indicated that at 1000 °C, the thermally sprayed NiCoCrAlY coating has greater... 

    Interaction between refractory crucible materials and the melted NiTi shape-memory alloy

    , Article Metallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science ; Volume 36, Issue 3 , 2005 , Pages 395-403 ; 10735615 (ISSN) Sadrnezhad, S. K ; Badakhshan Raz, S ; Sharif University of Technology
    Minerals, Metals and Materials Society  2005
    Abstract
    Attempts have been made to quantify the amount of contaminants absorbed by liquid metal from commercial ZrO2-, Al2O3-, and SiC-base crucibles used for vacuum melting of Ni-45 wt pet Ti alloy. The molten alloy was held under vacuum for 90 minutes at 1450°C to become homogenized. Reactions between the liquid metal and the crucible were investigated by visual observation, chemical analysis, scanning electron microscopy (SEM) image processing, and X-ray mapping. The relative degree of contamination declined in the following sequence: commercially pure SiC > SiC-5 wt pct Al2O3-5 wt pet SiO2] > slurry cast alumina > recrystallized alumina > zircon type A > oxygen deficient high-purity zirconia.... 

    Binary and ternary NiTi-based shape memory films deposited by simultaneous sputter deposition from elemental targets

    , Article Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films ; Volume 23, Issue 5 , 2005 , Pages 1425-1429 ; 07342101 (ISSN) Sanjabi, S ; Cao, Y. Z ; Sadrnezhaad, S. K ; Barber, Z. H ; Sharif University of Technology
    2005
    Abstract
    The most challenging requirement for depositing NiTi-based shape memory thin films is the control of film composition because a small deviation can strongly shift the transformation temperatures. This article presents a technique to control film composition via adjustment of the power supplied to the targets during simultaneous sputter deposition from separate Ni, Ti, and X (e.g., Hf) targets. After optimization of sputter parameters such as working gas pressure, target-substrate distance, and target power ratio, binary Ni100-x Tix thin films were fabricated and characterized by energy dispersive x-ray spectroscopy in a scanning electron microscope (to measure the film composition and... 

    Phase formation and microstructural evolution during sintering of Al-Zn-Mg-Cu alloys

    , Article Powder Metallurgy ; Volume 53, Issue 1 , 2010 , Pages 62-70 ; 00325899 (ISSN) Shah Mohammadi, M ; Simchi, A ; Gierl, C ; Sharif University of Technology
    2010
    Abstract
    Al–5·6Zn, Al–5·6Zn–2·5Mg and Al–5·6Zn–2·5Mg–1·6Cu (wt-%) powder blends were compacted at 350 MPa and sintered in nitrogen at different temperatures to study microstructural evolution during sintering. Densification, dimensional changes and mechanical properties of the Al alloys were investigated. Microstructural analyses were performed by scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and simultaneous thermal analysis (STA) in order to determine the temperature and chemical composition of the phases formed during sintering. It was shown that various liquids and intermetallic phases including Al0·71Zn0·29 at 438°C,... 

    Preparation and characteristics of epoxy/clay/B4C nanocomposite at high concentration of boron carbide for neutron shielding application

    , Article Radiation Physics and Chemistry ; Volume 141 , 2017 , Pages 223-228 ; 0969806X (ISSN) Kiani, M. A ; Ahmadi, S. J ; Outokesh, M ; Adeli, R ; Mohammadi, A ; Sharif University of Technology
    Abstract
    In this research, the characteristics of the prepared samples in epoxy matrix by means of X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), as well as scanning electron microscope (SEM) are evaluated. Meanwhile, the obtained mechanical properties of the specimen are investigated. Thermogravimetric analysis (TGA) is also employed to evaluate the thermal degradation of manufactured nanocomposites. The thermal neutron absorption properties of nanocomposites containing 3 wt% of montmorillonite nanoclay (closite30B) have been studied experimentally, using an Am-Be point source. Mechanical tests reveal that the higher B4C concentrations, the more tensile strengths, but lower... 

    Physical, morphological, and biological studies on PLA/nHA composite nanofibrous webs containing equisetum arvense herbal extract for bone tissue engineering

    , Article Journal of Applied Polymer Science ; Volume 134, Issue 39 , 2017 ; 00218995 (ISSN) Khakestani, M ; Jafari, S. H ; Zahedi, P ; Bagheri, R ; Hajiaghaee, R ; Sharif University of Technology
    Abstract
    A series of herbal extract incorporated into poly(lactic acid) (PLA) composite nanofibrous scaffolds were successfully prepared by using electrospinning technique. Equisetum arvense extract (EE) and nanohydroxyapatite (nHA) in different quantities were loaded into PLA solution to fabricate composite nanofibrous webs under various electrospinning conditions. Uniform nanofibers were obtained with an average diameter of 157 ± 47 nm in the case of those containing the herbal extract. Characterization of the webs was carried out by means of Fourier transform infrared (FTIR) spectroscopy, field emission-scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), and... 

    One step electrodeposition of V2O5/polypyrrole/graphene oxide ternary nanocomposite for preparation of a high performance supercapacitor

    , Article International Journal of Hydrogen Energy ; Volume 42, Issue 33 , 2017 , Pages 21073-21085 ; 03603199 (ISSN) Asen, P ; Shahrokhian, S ; Iraji zad, A ; Sharif University of Technology
    Abstract
    A new ternary nanocomposite based on graphene oxide (GO), polypyrrole (PPy) and vanadium pentoxide (V2O5) is obtained via one-step electrochemical deposition process. Electrochemical deposition of V2O5, PPy and GO on a stainless steel (SS) substrate is conducted from an aqueous solution containing vanadyl acetate, pyrrole and GO to get V2O5/PPy/GO nanocomposite. Characterization of the electrode material is carried out by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and atomic force microscopy (AFM). The electrochemical performance of the as-prepared nanocomposite is evaluated by...