نتایج جستجو برای: crystal lattice

تعداد نتایج: 244411  

Journal: :iranian journal of science and technology (sciences) 2015
x. tan

by analyzing the zero-field-splitting parameters and of cr2+ (3d4) ion located at tetrahedral site in znse crystal, the local structure distortion and absorption spectra around cr2+ in znse: cr2+ system have been calculated on the basis of the complete energy matrix for the d4 configuration within the strong-filed-representation. it is shown that there exists an expansion distortion in the loca...

2004
Qinjun Kang Dongxiao Zhang Peter C. Lichtner Ioannis N. Tsimpanogiannis

[1] We develop a new, lattice effects-free lattice Boltzmann model for simulating crystal growth from supersaturated solution. Simulations of crystal growth from a single or multiple nuclei in a domain initially filled with supersaturated solution are presented, such as in the case of gas hydrate formation. We find that as the process changes from diffusion-controlled to surface reaction-contro...

Ali Sadr, Alireza Kashani nia Ashkan Ghanbari,

 In this paper, we investigate the evolution of supercontinuum and femtosecond optical pulses generation through square lattice elliptical-core photonic crystal fiber (PCF) at 1550 nm by using both full-vector multipole method (M.P.M) and novel concrete algorithms: symmetric  split-step Fourier (SSF) and  fourth order Runge Kutta (RK4) which is an accurate method to solve the general  nonlinear...

Journal: :journal of optoelectronical nano structures 0
mahmoud nikoufard university of kashan masoud kazemi alamouti university of kashan

in this article, we suggested a novel design of polarization splitter based on coupler waveguide on inp substrate at 1.55mm wavelength. photonic crystal structure is consisted of two dimensional (2d) air holes embedded in inp/ingaasp material with an effective refractive index of 3.2634 which is arranged in a hexagonal lattice. the photonic band gap (pbg) of this structure is determined using t...

بخشی گرمی, فریال, بروستانی, جمال,

In this paper we studied the focusing effect of electromagnetic wave in the two-dimensional graded photonic crystal consisting of Silicon rods in the air background with gradually varying lattice constant. The results showed that graded photonic crystal can focus wide beams on a narrow area at frequencies near the lower edge of the band gap, where equal frequency contours are not concave. For c...

In this paper, a new structure is provided for the dispersion compensating photonic crystal fibers in order to broaden the chromatic dispersion and increase the dispersion compensating capability in a wide wavelength range. In the structure, putting a combination of circular holes and a star structure in the inner core clad causes the dispersion coefficient profile to be broadened, and addition...

In this paper, a new structure is provided for the dispersion compensating photonic crystal fibers in order to broaden the chromatic dispersion and increase the dispersion compensating capability in a wide wavelength range. In the structure, putting elliptical holes in the first ring of the inner core clad of a dispersion compensating fiber of the hexagonal lattice, increases the wavelength ran...

Journal: :international journal of nanoscience and nanotechnology 2014
m. khorasani-motlagh h. vahidi m. noroozifar

the perovskite-type oxides strontium-substituted lanthanum nickelate (lsno) were prepared by a coprecipitation method in the present of octanoic acid as surfactant. the phase composition, morphology,lattice parameters and size of nanoparticles in these materials were characterized through fourier transform infrared spectroscopy (ft-ir), x-ray diffraction (xrd), scanning electron microscopy (sem...

Journal: :journal of artificial intelligence in electrical engineering 2013
abolfazl abbaspour hamed alipour banaei alireza andalib

in this paper, using annular resonator we have designed an adding and dropping filter light based ontwo-dimensional photonic crystals. the shape of ring resonator filter adding and dropping that wehave proposed is race track. this filter has a hexagonal lattice structure of silicon bars withrefractive index 3/46 that is located in the context of air with refractive index 1. transmissionefficien...

Journal: :journal of artificial intelligence in electrical engineering 2013
reza ghavidel barsary alireza andalib hamed alipour-banaei

here, we propose an optical filter and an optical power splitter based on two-dimensionalphotonic crystal all circular ring resonators. these structures are made of a square lattice ofsilicon rods with the refractive index n1=3.464 surrounded by air (with refractive indexn2=1). first, we have designed the filter and by using that, we designed a power splitter. thetransmission efficiency and qua...

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