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    Role of second phase particles on microstructure and texture evolution of ARB processed aluminium sheets

    , Article Materials Science and Technology ; Volume 25, Issue 5 , 2009 , Pages 625-631 ; 02670836 (ISSN) Pirgazi, H ; Akbarzadeh, A ; Sharif University of Technology
    The accumulative roll bonding (ARB) process was carried out on a high purity alloy (AA1100) and a particle containing aluminium alloy (AA3003) for up to eight cycles. The electron backscattered diffraction (EBSD) method was utilised to investigate the microstructural and microtextural evolution in ARB processed sheets. The results indicate that the lack of second phase particles in pure aluminium hinders grain refinement and leads to the formation of unrefined bands, which results in the increase of the overall texture intensity and the development of a strong texture. Asubmicrometre grain structure in this alloy develops at the final stages of the process. It was also found that the... 

    Size, composition and optical properties of copper nanoparticles prepared by laser ablation in liquids

    , Article Applied Physics A: Materials Science and Processing ; Volume 88, Issue 2 , 2007 , Pages 415-419 ; 09478396 (ISSN) Tilaki, R. M ; Iraji Zad, A ; Mahdavi, M ; Sharif University of Technology
    Colloidal copper nanoparticles were prepared by pulsed Nd:YAG laser ablation in water and acetone. Size and optical properties of the nanoparticles were characterized by transmission electron microscopy and UV-visible spectrophotometry, respectively. The copper particles were rather spherical and their mean diameter in water was 30 nm, whereas in acetone much smaller particles were produced with an average diameter of 3 nm. Optical extinction immediately after the ablation showed surface plasmon resonance peaks at 626 and 575 nm for the colloidal copper in water and acetone, respectively. Time evaluation showed a blue shift of the optical extinction maximum, which is related to the change of... 

    Colloidal stability of dextran and dextran/poly ethylene glycol coated TiO2 nanoparticles by hydrothermal assisted sol-gel method

    , Article Ceramics International ; Volume 39, Issue 7 , 2013 , Pages 8377-8384 ; 02728842 (ISSN) Naghibi, S ; Madaah Hosseini, H. R ; Faghihi Sani, M. A ; Sharif University of Technology
    Colloidal stability of dextran (Dex) and Dex/poly ethylene glycol (PEG) coated TiO2 nanoparticles (NPs) were investigated. The particles were successfully synthesized by a hydrothermal assisted sol-gel technique. The results of Ultraviolet-visible (UV-vis) spectrophotometry showed that Dex and PEG additions during hydrothermal process (HTP) led to the formation of long-term (more than 60 days) stable colloids, while the addition of dispersants after HTP did not have a significant impact on the colloidal stability of NPs. X-ray diffraction (XRD) and selected area electron diffraction (SAED) analyses proved that PEG and/or Dex coated NPs had less crystallinity than the plain TiO2. Fourier... 

    Synthesis and crystallization of lead-zirconium-titanate (PZT) nanotubes at the low temperature using carbon nanotubes (CNTs) as sacrificial templates

    , Article Advanced Powder Technology ; Volume 23, Issue 5 , September , 2012 , Pages 647-654 ; 09218831 (ISSN) Mohammadi, M. R ; Tabei, S. A ; Nemati, A ; Eder, D ; Pradeep, T ; Sharif University of Technology
    Elsevier  2012
    Pb(Zr 0.52Ti 0.48)O 3 (PZT) nanotubes with diameters of 80-100 nm and a wall thickness of 15-20 nm were prepared by sol-gel template technique and using multi-walled carbon nanotubes (MWCNT) as sacrificial templates. The coating process of MWCNT with PZT precursor sol and removal of the carbon nanotubes by an interrupt heat treatment were discussed and studied by Raman spectroscopy. Simultaneous thermal analysis (STA) revealed that PZT nanotube crystallized at the low temperature of 410°C by the significantly low activation energy of crystallization of 103.7 kJ/mol. Moreover, based on the X-ray diffraction (XRD) pattern and selected area electron diffraction pattern the crystal structure of... 

    Electron back scattered diffraction (EBSD) characterization of warm rolled and accumulative roll bonding (ARB) processed ferrite

    , Article Journal of Materials Processing Technology ; Volume 209, Issue 3 , 2009 , Pages 1436-1444 ; 09240136 (ISSN) Kolahi, A ; Akbarzadeh, A ; Barnett, M. R ; Sharif University of Technology
    An interstitial free (IF) steel was severely deformed using accumulative roll bonding (ARB) process and warm rolling. The maximum equivalent strains for ARB and warm rolling were 4.8 and 4.0, respectively. The microstructure and micro-texture were studied using optical microscopy and scanning electron microscopy equipped with electron back scattered diffraction (EBSD). The grain size and misorientation obtained by both methods are in the same range. The microstructure in the ARB samples after 6 cycles is homogeneous, although a grain size gradient is observed at the layers close to the surface. The through thickness texture gradient in the ARB samples is different from the warm rolled... 

    High-performance enzyme-free glucose sensor with Co-Cu nanorod arrays on Si substrates

    , Article Recent Patents on Biotechnology ; Volume 12, Issue 2 , 2018 , Pages 126-133 ; 18722083 (ISSN) Shirinzadeh, H ; Yazdanpanah, A ; Karponis, D ; Aghabarari, B ; Tahmasbi, M ; Seifalian, A ; Mozafari, M ; Sharif University of Technology
    Bentham Science Publishers B.V  2018
    Background: Glucose sensors have been extensively researched in patent studies and manufactured a tool for clinical diabetes diagnosis. Although some kinds of electrochemical enzymatic glucose sensors have been commercially successful, there is still room for improvement, in selectivity and reliability of these sensors. Because of the intrinsic disadvantages of enzymes, such as high fabrication cost and poor stability, non-enzymatic glucose sensors have recently been promoted as next generation diagnostic tool due to their relatively low cost, high stability, prompt response, and accuracy. Objective: In this research, a novel free standing and binder free non-enzymatic electrochemical sensor... 

    Direct production of carbon nanotubes decorated with Cu2O by thermal chemical vapor deposition on Ni catalyst electroplated on a copper substrate

    , Article Journal of Nanoparticle Research ; Volume 13, Issue 10 , October , 2011 , Pages 4681-4689 ; 13880764 (ISSN) Nayeb Sadeghi, S ; Shafiekhani, A ; Vesaghi, M. A ; Sharif University of Technology
    Carbon nanotubes (CNTs) decorated with Cu2O particles were grown on a Ni catalyst layer deposited on a Cu substrate by thermal chemical vapor deposition from liquid petroleum gas. Ni catalyst nanoparticles with different sizes were produced in an electroplating system at 45 °C using the corrosive effect of H2SO4 which was added to solution. These nanoparticles provide the nucleation sites for CNT growth avoiding the need for a buffer layer. The surface morphology of the Ni catalyst films and CNT growth over this catalyst was studied by scanning electron microscopy (SEM). High temperature surface segregation of the Cu substrate into the Ni catalyst layer and its exposition to O2 at... 

    New gasochromic system: Nanoparticles in liquid

    , Article Journal of Nanoparticle Research ; Volume 14, Issue 4 , March , 2012 ; 13880764 (ISSN) Ranjbar, M ; Kalhori, H ; Mahdavi, S. M ; Zad, A. I ; Sharif University of Technology
    In this study, WO 3 nanocrystallites were first produced by laser ablation of W target in deionised water. To synthesize palladium, a PdCl 2 solution (0.2 g/L) was added to the liquid. Transmission electron microscope revealed successful synthesis of tungsten oxide nanocrystallites along with the production of Pd and core-shell Pd/WO3 nanoparticles. Gasochromic behavior was examined by hydrogen bubbling into Pd/WO 3 liquid in which a transition to blue absorbing state was observed. Optical absorption spectra of the colored liquid represented different sharp small polaron absorbing peaks below 3 eV and the peaks intensity was observed to be varied with Pd:WO 3 ratio. Time variations of... 

    Templated growth of superparamagnetic iron oxide nanoparticles by temperature programming in the presence of poly(vinyl alcohol)

    , Article Thin Solid Films ; Volume 518, Issue 15 , 2010 , Pages 4281-4289 ; 00406090 (ISSN) Mahmoudi, M ; Simchi, A ; Imani, M ; Stroeve, P ; Sohrabi, A ; Sharif University of Technology
    Magnetite (Fe3O4) nanostructures with different morphologies including uniform nanoparticles, magnetic beads and nanorods were synthesized via a co-precipitation method. The synthesis process was performed at various temperatures in the presence of polyvinyl alcohol (PVA) at different concentrations. It is shown that small amounts of PVA act as a template in hot water (70 °C), leading to the oriented growth of Fe3O4 nanorods, which was confirmed by selected area electron diffraction. Individually coated magnetite nanoparticles and magnetic beads were formed at a relatively lower temperature of 30 °C in the folded polymer molecules due to the thermo-physical properties of PVA. When a moderate... 

    Dynamic restoration and microstructural evolution during hot deformation of a P/M Al6063 alloy

    , Article Materials Science and Engineering A ; Volume 542 , April , 2012 , Pages 56-63 ; 09215093 (ISSN) Asgharzadeh, H ; Simchi, A ; Kim, H. S ; Sharif University of Technology
    Hot deformation behavior of Al6063 alloy produced by direct powder extrusion was studied by means of uniaxial compression test in the temperature range between 300 and 450°C and strain rate range between 0.01 and 1s -1. Electron backscatter diffraction (EBSD) technique and transmission electron microscopy (TEM) were utilized to study the microstructure of the material before and after the hot deformation. The microstructure of the extruded alloy consisted of elongated grains within a subgrain structure and small grains free of low angle grain boundaries (LAGBs). An equiaxed duplex microstructure consisting of large substructured grains and fine grains separated by high angle grain boundaries...