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Showing 2 results for Khosroshahi
Synthesis and characterization of gold nanoshells for biomedical applications
M.s. Nourbakhsh, M.e. Khosroshahi,
Volume 30, Issue 2 (Dec 2011)
Abstract
Gold nanoshells are a new type of nanoparticles including dielectric cores with a continuous thin layer of gold. By varying the core diameter, shell thickness, and the ratio of these parameters, the optical properties of gold nanoshells can be tuned to have maximum absorption in the visible and near infrared spectrum range. The purpose of this research was to synthesize gold coated SiO2 nanoshells for biomedical applications particularly laser tissue soldering. Nanoshells were synthesized using Stober method. The nanoshells were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, UV-visible spectroscopy and atomic force microscopy. The Fourier transform infrared spectroscopy confirmed the functionalization of the surfaces of silica nanoparticles with NH2 terminal groups. A tunable absorption was observed between 470-600 nm with a maximum range of 530-560 nm. Based on the X-ray diffraction, three main peaks of Au (111), (200) and (220) were identified. Also, atomic force microscopy results showed that the diameter of silica core was about 100 nm and the thickness of gold shell about 10 nm. This result showed that it is possible to use these nanoshells with visible and infrared lasers for biomedical applications.
Synthesis of Three-dimensional Graphene and Optimization of Its Morphology
Z. Khosroshahi, F. Karimzadeh, M. Kharaziha,
Volume 37, Issue 2 (Journal of Advanced Materials-Summer 2018)
Abstract
Due to electrical properties (high electron mobility) and electrochemical characteristics (high electron transport rate), graphene-based  materials have been widely applied for various scientific fields. However, due to their two-dimensional  structures, these materials have low active sites for reaction. Therefore, changing from two-dimensional sheets dimensional to the three-dimensional ones  could provide graphene-based materials with high specific surface and electron and mass transport particles. For these purpose, reduced graphene oxide (rGO) and polystyren (PS) aqueous solution were mixed with two different  weight ratios kinetic. In this study, the three-dimensional graphene (3DG) was synthesized with graphene oxide using sacrificial PS particles. For this purpose, rGO and the PS aqueous solution were mixed with two different weight ratios of 95:5 and 85:15. Then, the 3DG-PS scaffolds were synthesized by controlling the pH value in the range of 6-8. Subsequently, PS particles were removed by immersing the synthesized scaffolds in toluene. In this research, the effect of filtering through the member filter and centrifuge on the morphology of the  scaffolds was  investigated. The scaffolds were characterized with X-ray diffraction and scanning electron microscopy. The results showed the formation of 3DG with a uniform distribution of porosities by  using the  centrifuge procedure. Moreover, the sacrificial PS particles were completely removed when the rGO to PS weight ratio was 95:5. So, 3DG with the uniform distribution of microscopy porosity could be synthesized through the sacrificial mold method and the centrifuge procedure; graphene oxide was also reduced with the PS weight ratio of 95:5. Further, based on the electrochemical evaluation of  this optimized sample, as compared to the  rGO , it was found that the 3DG had better electrochemical properties than the rGO. Therefore, 3DG with  the optimized rGO to PS weight ratio of 95:5 could be an ideal substitute for rGO in electrochemical applications

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