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x--ray-spectroscopy
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The effect of titanium dioxide (TiO2) nanoparticles on hydroxyapatite (HA)/TiO2 composite coating fabricated by electrophoretic deposition (EPD)
, Article Journal of Materials Engineering and Performance ; Volume 27, Issue 5 , May , 2018 , Pages 2338-2344 ; 10599495 (ISSN) ; Afshar, A ; Salehi, S ; Sharif University of Technology
Springer New York LLC
2018
Abstract
Composite coatings of Hydroxyapatite (HA) with ceramics, polymers and metals are used to modify the surface structure of implants. In this research, HA/TiO2 composite coating was fabricated by electrophoretic deposition (EPD) on 316 stainless steel substrate. HA/TiO2 composite coatings with 5, 10 and 20 wt.% of TiO2, deposited at 40 V and 90 s as an optimum condition. The samples coated at this condition led to an adherent, continuous and crack-free coating. The influence of TiO2 content was studied by performing different characterization methods such as scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), corrosion resistance in simulated body fluid (SBF),...
Iron‑vanadium oxysulfide nanostructures as novel electrode materials for supercapacitor applications
, Article Journal of Electroanalytical Chemistry ; Volume 818 , 2018 , Pages 157-167 ; 15726657 (ISSN) ; Shahrokhian, S ; Iraji Zad, Azam ; Sharif University of Technology
Elsevier B.V
2018
Abstract
Iron‑vanadium oxysulfide (Fe-VO-S) nanostructures with different Fe:VO atomic ratios are synthesized by a facile and low cost electrochemical deposition method. The synthesis of the various samples is confirmed by the physicochemical characterizations such as Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and atomic force microscopy (AFM). For different Fe-VO-S nanostructures, the correlation between the physicochemical and the electrochemical properties is investigated. It is found that the Fe:VO atomic ratio has an important effect on the structure and size of the resulted particles....
Doxorubicin-conjugated D-glucosamine- and folate- bi-functionalised InP/ZnS quantum dots for cancer cells imaging and therapy
, Article Journal of Drug Targeting ; Volume 26, Issue 3 , 2018 , Pages 267-277 ; 1061186X (ISSN) ; Eskandani, M ; Johari Ahar, M ; Nemati, A ; Akbari, H ; Davaran, S ; Omidi, Y ; Sharif University of Technology
Taylor and Francis Ltd
2018
Abstract
Nanoscaled quantum dots (QDs), with unique optical properties have been used for the development of theranostics. Here, InP/ZnS QDs were synthesised and functionalised with folate (QD-FA), D-glucosamine (QD-GA) or both (QD-FA-GA). The bi-functionalised QDs were further conjugated with doxorubicin (QD-FA-GA-DOX). Optimum Indium to fatty acid (In:MA) ratio was 1:3.5. Transmission electron microscopy (TEM) micrographs revealed spherical morphology for the QDs (11 nm). Energy-dispersive spectroscopy (EDS) spectrum confirmed the chemical composition of the QDs. MTT analysis in the OVCAR-3 cells treated with bare QDs, QD-FA, QD-GA, QD-FA-GA and QD-FA-GA-DOX (0.2 mg/mL of QDs) after 24 h indicated...
Runaway electron energy measurement using hard x-ray spectroscopy in "damavand" tokamak
, Article Review of Scientific Instruments ; Volume 80, Issue 1 , 2009 ; 00346748 (ISSN) ; Iraji, D ; Farahbod, A. H ; Akhtari, K ; Rasouli, H ; Modarresi, H ; Lamehi, M ; Sharif University of Technology
2009
Abstract
Set of experiments has been developed to study existing runaway electrons in "Damavand" tokamak plasma upon characteristics of hard x-ray emissions produced by collision of the runaway electrons with the plasma particles and limiters. As a first step, spatial distribution of hard x-ray emissions on the equatorial plane of the torus was considered. Obtained spectra of hard x-ray emissions for different alignments of shielded detector indicate isotropic emissivity in the equatorial plane. This is in agreement with wide angle cone of bremsstrahlung radiations, deduced from the mean value of energy of the runaway electrons. The mean energy was calculated from the slope of the energy spectrum of...
Effect of rare earth elements addition on thermal fatigue behaviors of AZ91 magnesium alloy
, Article Journal of Rare Earths ; Volume 27, Issue 2 , 2009 , Pages 255-258 ; 10020721 (ISSN) ; Saebnoori, E ; Sharif University of Technology
Chinese Society of Rare Earths
2009
Abstract
Influences of rare earth (RE) elements addition on thermal fatigue behaviors of AZ91 alloy were studied. Repeated heating and cooling cycles were applied on the samples at 170 and 210 °C to develop thermal fatigue cracks. Crack growth mechanisms and microstructural influences were investigated by optical and scanning electron microscopy (SEM) as well as energy dispersive X-ray spectroscopy (EDS). Thermal fatigue behaviors were observed to improve successively by addition of the RE up to 2wt.%. This improvement was attributed to the consummation of aluminum in melt by precipitation of the needle shaped Al11RE3 phases. This process was attributed to the reduction of Mg17Al12 phase volume...
Origin of apparent light-enhanced and negative capacitance in perovskite solar cells
, Article Nature Communications ; Volume 10, Issue 1 , 2019 ; 20411723 (ISSN) ; Taghavinia, N ; Mohammadpour, R ; Hagfeldt, A ; Tress, W ; Sharif University of Technology
Nature Publishing Group
2019
Abstract
So-called negative capacitance seems to remain an obscure feature in the analysis of the frequency-dependent impedance of perovskite solar cells. It belongs to one of the puzzling peculiarities arising from the mixed ionic-electronic conductivity of this class of semiconductor. Here we show that apparently high capacitances in general (positive and negative) are not related to any capacitive feature in the sense of a corresponding charge accumulation. Instead, they are a natural consequence of slow transients mainly in forward current of the diode upon ion displacement when changing voltage. The transient current leads to a positive or negative ‘capacitance’ dependent on the sign of its...
Optimum rice husk ash content and bacterial concentration in self-compacting concrete
, Article Construction and Building Materials ; Volume 222 , 2019 , Pages 796-813 ; 09500618 (ISSN) ; Shoaei, P ; Bahrami, N ; Vaezi, M ; Ozbakkaloglu, T ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
This study is aimed at optimizing the rice husk ash (RHA) content and bacterial concentration in self-compacting concrete (SCC). For this purpose, cement was partially replaced with RHA at 0%, 5%, 10%, 15%, 20%, 25%, and 30% by weight of cement. In addition, micro-silica (MS) was added to all mixes at a dosage of 10% by weight of cementitious materials. The mix with the optimum RHA content was supplied with bacterial cells with concentrations of 103, 105, and 107 cells/ml to reduce the formation of micro-cracks. The RHA concretes showed reduced workability with increasing RHA content. Energy-dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM) analyses were performed on...
Continuous synthesis of barium sulfate nanoparticles in a new high-speed spinning disk reactor
, Article Industrial and Engineering Chemistry Research ; Volume 58, Issue 36 , 2019 , Pages 16597-16609 ; 08885885 (ISSN) ; Molaei Dehkordi, A ; Sharif University of Technology
American Chemical Society
2019
Abstract
A new high-speed spinning disk reactor (HSSDR) was proposed and tested successfully. In this regard, barium sulfate (BaSO4) nanoparticles were synthesized using reactive crystallization processes. In this reactor, the rotational disk speed was varied from 5000 to 15 000 rpm. The effects of various design and operating parameters such as the rotational disk speed, feed entrance radius, volumetric flow rate of feed solutions, supersaturation, and free ion ratio were investigated in detail. The mean particle size (MPS) and specifications of the synthesized barium sulfate were investigated using scanning electron microscopy combined with energy-dispersive X-ray spectroscopy and powder X-ray...
Preparation of sulfur micro-particles suitable for lithium sulfur batteries using sulfur vapor deposition
, Article Materials Research Express ; Volume 6, Issue 10 , 2019 ; 20531591 (ISSN) ; Borzabadi Farahani, A ; Sanaee, Z ; Ghasemi, S ; Mohajerzadeh, S ; Sharif University of Technology
Institute of Physics Publishing
2019
Abstract
The current paper reports the deposition of sulfur micro-particles using sulfur vapor deposition (SVD). Sulfur particles in size of 5 to 45 μm were deposited on a stainless steel substrate to be used as the cathode with porous structure in lithium sulfur (Li-S) batteries. Mass loading of about 0.5 mg cm-2 was obtained from this pure sulfur cathode. The structure of this binder-free cathode was characterized by field emission scanning electron microscopy (FESEM), x-ray spectroscopy (EDS), and x-ray diffraction (XRD). The electrochemical performance of the battery with two different organic liquid ether- and carbonate-based electrolytes was investigated and the results demonstrated that the...
Hexagonal core–shell SiO2[–MOYI]Cl–]Ag nanoframeworks for efficient photodegradation of the environmental pollutants and pathogenic bacteria
, Article Journal of Inorganic and Organometallic Polymers and Materials ; Volume 29, Issue 4 , 2019 , Pages 1314-1323 ; 15741443 (ISSN) ; Asgarpour, F ; Akbari, A ; Eftekhari Sis, B ; Lammel, G ; Sharif University of Technology
Springer New York LLC
2019
Abstract
Hexagonal core–shell SiO2[–MOYI]Cl–]Ag nanoframeworks were synthesized via surface modification of hexagonal silica nanoparticles prepared from perlite (EP) as a cheap and abundant raw material. The prepared samples were well characterized by X-ray diffraction powder (XRD), energy dispersive X-ray (EDX), diffuse reflectance spectroscopy (DRS), Brunauer–Emmett–Teller (BET) specific surface area analysis, fourier transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM). The XRD patterns confirmed that Ag and AgCl crystalline phases were successfully loaded on the surface. The TEM images were also implied that the...
Synthesis of NiAl-TiC composites from elemental powders by volume combustion method
, Article Materials Science and Technology (United Kingdom) ; Volume 35, Issue 7 , 2019 , Pages 831-838 ; 02670836 (ISSN) ; Minagar, A ; Naseri, G ; Bahmani, A ; Malekan, M ; Sharif University of Technology
Taylor and Francis Ltd
2019
Abstract
NiAl-TiC composites were synthesised by volume combustion (VC) method from elemental powders to improve the mechanical properties and high temperature performance of nickel aluminide. Synthesised specimens with porous nature were characterised by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analysis. XRD results showed that NiAl was dominant phase and other phases like Al 3 Ni 2 (in NiAl + 5 wt-% TiC, NiAl + 10 wt-% TiC specimens) and AlNi 3 (in equimolar NiAl-TiC) were present in specimens. Synthesised specimens of NiAl, NiAl + 5 wt-% TiC, NiAl + 10 wt-% TiC, NiAl + 15 wt-% TiC and equimolar NiAl-TiC achieved Vickers...
One step synthesis of SnS2-SnO2 nano-heterostructured as an electrode material for supercapacitor applications
, Article Journal of Alloys and Compounds ; Volume 782 , 2019 , Pages 38-50 ; 09258388 (ISSN) ; Haghighi, M ; Shahrokhian, S ; Taghavinia, N ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
SnS2-SnO2 nano-heterostructures are synthesized with two different precursors of thioacetamide (TAA) and thiourea (TU) at various solvent ratios (SR) of ethanol and water by using a facile, economical, scalable, and cost-effective solvothermal method. The obtained products have been characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDX), and Brunauer–Emmet–Teller (BET) techniques. It is found that different precursors and various SR values have an influence on the composition and morphologies of the prepared nanostructures, leading to variation in capacitive behavior of the fabricated electrodes....
Investigation on the wear properties of Ti/TiC/TiN composite coatings prepared by powder cored wires through TIG method at nitrogen atmosphere on titanium substrate
, Article Materials Research ; Volume 22, Issue 2 , 2019 ; 15161439 (ISSN) ; Allahyari, A. A ; Sharif University of Technology
Universidade Federal de Sao Carlos
2019
Abstract
In this present study, Tungsten Inert Gas (TIG) welding and powder filled cored wires with nitrogen shielding gas were utilized to produce TiC and TiN surface composite coatings on the titanium (Ti) sheet substrate. The TIG procedure was done at same welding parameters for all of prepared samples. Phase analysis and microstructures were done by X-ray Diffraction (XRD), Energy-Dispersive X-ray Spectroscopy (EDS), Optical Microscopy (OM) and Scanning Electron Microscopy (SEM). The obtained results from XRD and EDS demonstrated that the presence of crystalline phases of TiC, TiN and Ti. SEM and OM exhibited formation of the spherical and dendritic TiC particles in a martensitic matrix and also,...
Investigation on the wear properties of Ti/TiC/TiN composite coatings prepared by powder cored wires through TIG method at nitrogen atmosphere on titanium substrate
, Article Materials Research ; Volume 22, Issue 2 , 2019 ; 15161439 (ISSN) ; Ammari Allahyari, A ; Sharif University of Technology
Universidade Federal de Sao Carlos
2019
Abstract
In this present study, Tungsten Inert Gas (TIG) welding and powder filled cored wires with nitrogen shielding gas were utilized to produce TiC and TiN surface composite coatings on the titanium (Ti) sheet substrate. The TIG procedure was done at same welding parameters for all of prepared samples. Phase analysis and microstructures were done by X-ray Diffraction (XRD), Energy-Dispersive X-ray Spectroscopy (EDS), Optical Microscopy (OM) and Scanning Electron Microscopy (SEM). The obtained results from XRD and EDS demonstrated that the presence of crystalline phases of TiC, TiN and Ti. SEM and OM exhibited formation of the spherical and dendritic TiC particles in a martensitic matrix and also,...
Stick-slip behavior of sessile drop on the surfaces with irregular roughnesses
, Article Chemical Engineering Research and Design ; Volume 160 , 2020 , Pages 216-223 ; Shayesteh, M ; Shafiei, Y ; Ghazanfari, M. H ; Sharif University of Technology
Institution of Chemical Engineers
2020
Abstract
In this work, sessile drop and low-bond axisymmetric drop shape analysis methods were coupled to provide some new aspects on stick-slip behavior as well as stick time of a drop on calcite surfaces. Slightly hydrophobic calcite surfaces typified with three irregular roughnesses were used to create irregular surfaces to mimic defects for the water-calcite-air systems. Polishing papers of 200, 600, and 1200 grit and a polishing machine were used to prepare surfaces. X-ray diffraction, energy dispersive X-ray spectroscopy, Fourier transform infrared, and atomic force microscopy techniques were employed to evaluate the chemical and physical properties of surfaces. A model was developed to predict...
Pectic acid–graphene oxide nanocomposite as an adsorbent in vortex-assisted dispersive solid-phase extraction for preconcentration of copper ion followed by flame atomic absorption spectrometry
, Article Polymer Bulletin ; Volume 77, Issue 6 , 2020 , Pages 2821-2836 ; Shakerian, M ; Majeed, H. J ; Eftekhari, M ; Rezazadeh, N ; Sharif University of Technology
Springer
2020
Abstract
An efficient, green, novel and rapid vortex-assisted dispersive solid-phase extraction (VADSPE) technique was used for the preconcentration and determination of trace levels of Cu2+ followed by flame atomic absorption spectrometry. Graphene oxide (GO) was synthesized from graphite and then modified by pectic acid (poly-d-galacturonic acid, PA) to synthesize the pectic acid–graphene oxide (PA-GO) nanocomposite. The Fourier transform infrared spectrophotometry, field emission scanning electron microcopy, energy-dispersive X-ray spectroscopy and X-ray diffraction analysis were used to characterize the synthesized GO-PA nanocomposite. By using VADSPE technique, PA-GO was used as an adsorbent for...
In situ synthesis of quasi-needle-like bimetallic organic frameworks on highly porous graphene scaffolds for efficient electrocatalytic water oxidation
, Article Chemical Communications ; Volume 56, Issue 21 , 2020 , Pages 3135-3138 ; Hasanzadeh, M ; Mojaddami, M ; Shahriyar Far, H ; Simchi, A ; Sharif University of Technology
Royal Society of Chemistry
2020
Abstract
We present enhanced electrocatalytic activity of three-dimensional graphene scaffolds by decoration with one-dimensional CoxNi1-x MOF nanostructures (0 ≤ x ≤ 1). The decreased overpotential and fast kinetics of the oxygen evolution reaction as compared with the existing materials are shown. The developed bimetallic MOF/3DG composites have great potential to be used in electrocatalytic water oxidation. This journal is © The Royal Society of Chemistry
Electrospun chitosan/polyvinyl alcohol nanocomposite holding polyaniline/silica hybrid nanostructures: An efficient adsorbent of dye from aqueous solutions
, Article Journal of Molecular Liquids ; Volume 331 , 2021 ; 01677322 (ISSN) ; Tati, A ; Ahmadipouya, S ; Haddadi, S. A ; Arjmand, M ; Sharif University of Technology
Elsevier B.V
2021
Abstract
In this work, the addition of a novel polyaniline (PANI)/silica (SiO2) nanostructure (PSn) in chitosan/polyvinyl alcohol nanofibers (CP) was evaluated to enhance the dye removal capacity of CP. Fourier transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy (FE-SEM), and energy-dispersive X-ray spectroscopy (EDS) results confirmed the chemical grafting of SiO2 on PANI nanoparticles. Brunauer-Emmett-Teller (BET) results showed a specific surface area of 61 m2 g−1 for the PSn filled CP nanofiber (CP-PSn). FE-SEM and EDS-elemental mapping results showed the uniform dispersibility of PSn in CP nanofibers. After the addition of PSn into CP, the adsorption capacity of...
A novel low-temperature growth of uniform CuInS2 thin films and their application in selenization/sulfurization-free CuInS2 solar cells
, Article Materials Today Communications ; Volume 26 , 2021 ; 23524928 (ISSN) ; Parvazian, E ; Alamgir Tehrani, N ; Taghavinia, N ; Samadpour, M ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
In terms of manufacturability, there is a high tendency to deposit light-absorbing CuInS2 films by solution processing methods like ink-based depositions. In particular, for nanoparticle inks, the synthesis of highly dispersed and stable inks, with uniformity in the deposition process, is a serious challenge. Here, we demonstrate a novel two-step low-temperature CuInS2 film deposition method in which the In2S3 is deposited first. It then partially is converted into CuInS2 through the infiltration of Cu+ ions in the In2S3 layer in a dip-coating process. The resulting films are highly uniform, with diffraction peaks indicating the formation of pure CuInS2 phase. The proper stoichiometry of...
Efficacy of a novel bioactive glass-polymer composite for enamel remineralization following erosive challenge
, Article International Journal of Dentistry ; Volume 2022 , 2022 ; 16878728 (ISSN) ; Heidari, S ; Najafi, F ; Hajihasani, M ; Noshiri, N ; Nazari, N. F ; Sharif University of Technology
Hindawi Limited
2022
Abstract
Introduction. Dental caries is the most common cause of tooth loss. However, it can be stopped by enhancing remineralization. Fluoride and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) are among the most important remineralizing agents. Recent studies have used bioactive glass as a remineralizing agent in different forms. This study aimed to assess the efficacy of a composite paste (prepared by mixing urethane polypropylene glycol oligomer with bioactive glass powder for easier application). Materials and Methods. Enamel disks were cut out of the buccal surface of extracted sound third molars. The samples were randomly divided into 3 groups of 15 and underwent Vickers...