Sharif Digital Repository

Cadmium sulfide (CdS) with different morphologies was successfully prepared by solvothermal process by controlling the processing parameters, including nature of precursor and solvent, reaction temperature and process time. X-ray diffraction patterns revealed that, in all cases highly pure and crystallized CdS with hexagonal structure were obtained. In addition, it was found that the processing parameters influence on preferable growth direction of CdS nanostructures. Field emission scanning electron microscope analysis showed that CdS nanowires with different aspect ratios were obtained (depending upon the reaction temperature and process time) in presence of sulfur powder and... 

Perovskite-type barium strontium titanate (BST) thin films and powders with nanocrystalline and mesoporous structure were prepared by a straightforward particulate sol-gel route at room temperature. The prepared sol had a narrow particle size distribution of about 20 nm. X-ray diffraction (XRD) revealed that phase composition and preferable orientation growth of BST depended upon the annealing temperature. Transmission electron microscope (TEM) images showed that the crystallite size of the powders decreased with increasing annealing temperature from 8 nm at 25 °C down to 5 nm at 800 °C. Field emission scanning electron microscope (FE-SEM) analysis and atomic force microscope (AFM) images... 

TiO2 nanorods have been successfully grown into a track-etched polycarbonate (PC) membrane by a particulate sol-electrophoretic deposition from an aqueous medium. The prepared sols had a narrow particle size distribution around 17 nm and excellent stability against aging, with zeta potentials in the range of 47-50 mV at pH 2. It was found that TiO2 nanorods were grown from dilute aqueous sol with a low, 0.1-M concentration. Fourier transform infrared spectroscopy (FT-IR) analysis confirmed that a full conversion of titanium isopropoxide was obtained by hydrolysis, resulting in the formation of TiO2 particles. X-ray diffraction (XRD) results revealed that TiO2 nanorods dried at 100 °C were a... 

Nanocrystalline nickel titanate (NiTiO3) thin films and powders with mesoporous structure were produced at the low temperature of 500 °C by a straightforward particulate sol-gel route. The sols were prepared in various Ni:Ti molar ratios. X-ray diffraction and Fourier transform infrared spectroscopy revealed that the powders contained mixtures of the NiTiO 3 and NiO phases, as well as the anatase-TiO2 and the rutile-TiO2 depending on the annealing temperature and Ni:Ti molar ratio. Moreover, it was found that Ni:Ti molar ratio influences the preferable orientation growth of the nickel titanate, being on (202) planes for the nickel dominant powders (Ni:Ti ≥ 75:25) and on (104) planes for the... 

Low temperature lithium titanate compounds (i.e., Li4Ti 5O12 and Li2TiO3) with nanocrystalline and mesoporous structure were prepared by a straightforward aqueous particulate sol-gel route. The effect of Li:Ti molar ratio was studied on crystallisation behaviour of lithium titanates. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) revealed that the powders were crystallised at the low temperature of 500 °C and the short annealing time of 1 h. Moreover, it was found that Li:Ti molar ratio and annealing temperature influence the preferable orientation growth of the lithium titanate compounds. Transmission electron microscope (TEM) images showed that the average... 

The objective of this paper is to study the influence of the second peak temperature during real and simulated welding on properties of the subcritically (S), intercritically (IC) and supercritically (SC) reheated coarse grained heat affected (CGHAZ) zones. The X80 high strength pipeline microalloyed steel was subject to processing in a double-pass tandem submerged arc welding process with total heat input of 6.98 kJ/mm and thermal cycles to simulate microstructure of reheated CGHAZ zones. This involved heating to a first peak temperature (TP1) of 1400 °C, then reheating to different second peak temperatures (TP2) of 700, 800 and 900 °C with a constant cooling rate of 3.75 °C/s. Toughness of... 

In this research, the effect of applied voltage and electrolyte concentration on structure, chemical composition, optical properties, and especially photo-catalytic activity of the TiO2 layers containing micro/nano-sized pores are discussed. TiO2 layers were synthesized by micro arc oxidation (MAO) process using different electrolyte concentrations and applied voltages. Surface structure of the layers was studied by scanning electron microscope (SEM); furthermore, energy dispersive spectrophotometry (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) techniques were employed to determine phase structure and chemical composition of the layers. Photo-activity of the... 

Micro-arc oxidation process was used to synthesize V2O5-TiO2 porous layers for the first time. Surface morphology and topography of the layers were investigated by scanning electron microscope (SEM) and atomic force microscope (AFM). X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques were also employed to evaluate phase structure and chemical composition of the layers. It was found that the V2O5-TiO2 layers consisted of anatase, rutile, and vanadium pentoxide phases fraction of which varied with the applied voltage and the electrolyte concentration. It was also revealed that pore size and surface roughness increased with the applied voltage and the electrolyte... 

Nanocrystalline zinc titanate (ZnTiO3) thin films and powders with purity of 94% were produced at the low sintering temperature of 500 °C and the short sintering time of 1 h by a straightforward aqueous particulate sol-gel route. The effect of Zn:Ti molar ratio was studied on the crystallisation behaviour of zinc titanates. The prepared sols showed a narrow particle size distribution in the range 17-19 nm. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) revealed that the powders contained mixtures of the rhombohedral-ZnTiO3, cubic-ZnO, cubic-Zn2TiO4 phases, as well as the anatase-TiO2 and the rutile-TiO2 depending on the sintering temperature and Zn:Ti molar ratio.... 

V2O5-TiO2 layers with a sheet-like morphology were synthesized by micro arc oxidation process for the first time. Surface morphology and topography of the layers were investigated by scanning electron microscope (SEM) and atomic force microscope (AFM). Phase structure and chemical composition of the layers were also studied by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques. It was revealed that the composite layers had a sheet-like structure average thickness of which was about 100 nm depending on the applied voltage. The layers consisted of anatase, rutile, and vanadium pentoxide phases fractions of which varied with the applied voltage. The optical properties... 

To improve the biocompatibility and corrosion resistance of 316L SS (Stainless Steel) metal implants, HAp(hydroxyapatite)/TiO2/Al2O3 nanocomposite coating was created using dip sol-gel method sintered at 550 °C. The weight percentage of TiO2+ Al2O3 in these coatings was 20, 30, and 40% wt. In this study, characterization was performed using FTIR (Fourier-Transform Infrared Spectroscopy), XRD, FE-SEM (Field Emission Scanning Electron Microscope), EDS (Energy Dispersive Spectroscopy), DLS (Dynamic Light Scattering), Pull-off, and AFM (Atomic Force Microscopy) analysis. The potentiodynamic polarization and EIS (Electrochemical Impedance Spectroscopy) were performed in the simulated body fluid... 

A new technique for preparation of an unbreakable solid-phase microextraction (SPME) fiber, using sol-gel technology is developed. Primarily, an ultrathin two-dimensional intermediate film was prepared by hydrolysis of 3-(trimethoxysilyl)-1-propanthiol self-assembled monolayer grafted onto gold, then a stationary phase by electrodeposition of 3-(trimethoxysilyl) propylmethacrylate as a precursor, tetramethyl orthosilicate and polyethylene glycol as a coating polymer was produced. The scanning electron microscopy images revealed that the new fiber exhibits a rather porous and homogenous surface. The thermal stability of the fabricated fiber was investigated by thermogravimetric analysis. The... 

Nanostructured TiO2-ZrO2 thin films and powders were prepared by a straightforward aqueous particulate sol-gel route. Titanium (IV) isopropoxide and zirconium (IV) acetate hydrate were used as precursors, and hydroxypropyl cellulose was used as a polymeric fugitive agent in order to increase the specific surface area. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy revealed that the powder were crystallised at the low temperature of 500 °C, containing anatase-TiO 2 and tetragonal-ZrO2 phases. Furthermore, it was found that ZrO2 retarded the anatase-to-rutile transformation up to 900 °C. The activation energies for crystallite growth of TiO2 and ZrO2 components in... 

Nanostructured TiO2-CeO2 thin films and powders were prepared by a straightforward aqueous particulate sol-gel route. Titanium (IV) isopropoxide and cerium chloride were used as precursors, and hydroxypropyl cellulose was used as a polymeric fugitive agent in order to increase the specific surface area. The effect of Ce:Ti molar ratio was studied on the crystallisation behaviour of the products. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) revealed that the powders crystallised at the low temperature of 500 °C, containing anatase-TiO2, rutile-TiO2 and cubic-CeO2 phases, as well as Ti 8O15, Ti3O5 and Ce 11O20 depending on annealing temperature and Ce:Ti molar... 

Nanocrystalline neodymium titanium oxide thin films and powders with different phase compositions with mesoporous structure were produced by a straightforward particulate sol-gel route. The sols were prepared in various Nd:Ti molar ratios and they showed a narrow particle size distribution in the range 20-26 nm. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) revealed that the powders contained mixtures of Nd4Ti9O24, Nd2Ti4O11, Nd3Ti4O12 for titanium dominant powders (Nd:Ti ≤ 45:60), mixtures of Nd2TiO5 and Nd2O3 for neodymium dominant powders (Nd:Ti ≥ 75:25) and pure Nd3Ti4O12 phase for equal molar ratio of Nd:Ti, depending on the annealing temperature and Nd:Ti... 

In this study, a new facile and cost effective method is used to modify polysulfone membrane surface in order to improve the hydrophilicity, antifouling, and blood compatibility. This modification was performed by adding two functional monomers on the dialysis membrane. Polysulfone (PSF) membranes containing polyvinylpyrrolidone were prepared via phase inversion technique. In the next step, free radical polymerization combined with surface polymerization was used to introduce acrylic acid (AA) and 2-hydroxyethyl methacrylate (HEMA) onto the polysulfone membrane surface via circulation of initiator and monomer solutions across the membrane surface, respectively. Various monomer concentrations... 

Herein, the NH2-UiO-66 metal organic framework (MOF) has been green synthesized with the assistance of high gravity to provide a suitable and safe platform for drug loading. The NH2-UiO-66 MOF was characterized using a field-emission scanning electron microscope, transmission electron microscope (TEM), X-ray diffraction, and zeta potential analysis. Doxorubicin was then encapsulated physically on the porosity of the green MOF. Two different stimulus polymers, p(HEMA) and p(NIPAM), were used as the coating agents of the MOFs. Doxorubicin was loaded onto the polymer-coated MOFs as well, and a drug payload of more than 51% was obtained, which is a record by itself. In the next step, pCRISPR was...