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diffraction-gratings
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Fast convergent Fourier modal method for the analysis of periodic arrays of graphene ribbons
, Article Optics Letters ; Volume 38, Issue 16 , 2013 , Pages 3009-3012 ; 01469592 (ISSN) ; Sharif University of Technology
2013
Abstract
Li's Fourier factorization rules [J. Opt. Soc. Am. A 13, 1870 (1996)] should be applied to achieve a fast convergence rate in the analysis of diffraction gratings with the Fourier modal method. I show, however, that Li's inverse rule cannot be applied for periodic patterns of graphene when the conventional boundary condition is used. I derive an approximate boundary condition in which a nonzero but sufficiently small height is assumed for the boundary. The proposed boundary condition enables us to apply the inverse rule, leading to a significantly improved convergence rate. A periodic array of graphene ribbons is in fact a special type of finite-conductivity strip grating, and thus the...
Rapid formation of hydroxyapatite nanostrips via microwave irradiation
, Article Journal of Alloys and Compounds ; Volume 469, Issue 1-2 , 2009 , Pages 391-394 ; 09258388 (ISSN) ; Mohajerani, M ; Mazloumi, M ; Khalifehzadeh, R ; Lak, A ; Sadrnezhaad, S. K ; Sharif University of Technology
2009
Abstract
Hydroxyapatite (HAp) nanostrips were rapidly obtained during a mild microwave heating method. Applying microwave irradiation to Ca(NO3)2·4H2O/CTAB/Na2HPO4 precursor solution, the HAp precipitation process was occurred directly and without common crystallographic transformations including dissolution and slow recrystallization. The cationic surfactant CTAB was used as a soft template to modify nucleation and growth process. TEM investigations showed that the fabricated nanostrips had a width and length of about 10 and 55 nm, respectively. The X-ray diffraction pattern revealed that the fabricated well-crystallized and high purity hydroxyapatite nanostrips had a pattern similar to the bone...