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    Synthesis of thoria nanoparticles via the hydrothermal method in supercritical condition

    , Article Materials Letters ; Volume 81 , 2012 , Pages 99-101 ; 0167577X (ISSN) Moeini, M ; Malekzadeh, A ; Ahmadi, S. J ; Hosseinpour, M ; Sharif University of Technology
    Elsevier  2012
    Thorium dioxide (thoria) nano-particle was synthesized by employing supercritical water (SCW) as an excellent reaction environment for hydrothermal crystallization of metal oxide particles. This method is ideal for production of ultrafine powder having controlled stoichiometry, high quality, purity and crystallinity. The nano-crystalline thoria was prepared in a stainless steel (316 L) autoclave, fed with an aqueous solution of Th(NO 3) 4.5H 2O as a reactant and took place under SCW condition up to 450 °C for 45 min. The product was recovered and characterized by X-Ray Diffraction (XRD), Thermal Gravimetry Analysis (TG/DTA) and Brunauer, Emmett and Teller (BET) surface area analysis. The... 

    Complete steric exclusion of ions and proton transport through confined monolayer water

    , Article Science ; Volume 363, Issue 6423 , 2019 , Pages 145-148 ; 00368075 (ISSN) Gopinadhan, K ; Hu, S ; Esfandiar, A ; Lozada Hidalgo, M ; Wang, F. C ; Yang, Q ; Tyurnina, A. V ; Keerthi, A ; Radha, B ; Geim, A. K ; Sharif University of Technology
    American Association for the Advancement of Science  2019
    It has long been an aspirational goal to create artificial structures that allow fast permeation of water but reject even the smallest hydrated ions, replicating the feat achieved by nature in protein channels (e.g., aquaporins). Despite recent progress in creating nanoscale pores and capillaries, these structures still remain distinctly larger than protein channels. We report capillaries made by effectively extracting one atomic plane from bulk crystals, which leaves a two-dimensional slit of a few angstroms in height. Water moves through these capillaries with little resistance, whereas no permeation could be detected even for such small ions as Na + and Cl − . Only protons (H + ) can... 

    CMC/celite superabsorbent composites: Effect of reaction variables on saline-absorbency under load

    , Article Iranian Polymer Journal (English Edition) ; Volume 19, Issue 8 , May , 2010 , Pages 571-579 ; 10261265 (ISSN) Pourjavadi, A ; Soleyman, R. A ; Ghasemzadeh, H ; Salimi, H ; Sharif University of Technology
    A series of superabsorbent composites were synthesized through graft copolymerization of acrylic acid (AA) onto carboxymethyl cellulose (CMC) in the presence of celite powder using N,N'-methylenebisacrylamide (MBA) as a cross-linking agent and ammonium persulphate (APS) as an initiator. The chemical structure and thermal properties of the composite hydrogels were characterized by FTIR spectroscopy and TGA methods, respectively. Morphology of the samples was examined by scanning electron microscopy (SEM). In free-state, the swelling conditions and hence the related data are not real, because in all their applications the swelling particles of superabsorbent must absorb aqueous solutions while...