Hasan Pakarzadeh; Rezvan Derakhshan
Volume 1, Issue 2 , November 2016, Pages 9-16
Abstract
Photonic crystal fibers (PCFs) are new class of optical fibers which have great potentials and various applications. In this article, we investigate and simulate the impacts of structural parameters on mode characteristics of PCFs in telecommunication region that little attention has been paid to it ...
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Photonic crystal fibers (PCFs) are new class of optical fibers which have great potentials and various applications. In this article, we investigate and simulate the impacts of structural parameters on mode characteristics of PCFs in telecommunication region that little attention has been paid to it by using CUDOS MOF software. Here, PCFs are simulated in two different schemes: one with increasing the number of air rings in the cladding area and the other one with increasing the filling fraction; and then the best PCF for the single-mode operation in telecommunication region with the lowest confinement loss is introduced. Also, the wavelength dependence of the loss, effective mode area, and effective mode refractive index is simulated. The results show that with increasing the number of air rings in the cladding as well as the air filling fraction, the PCF losses, effective mode area, and effective mode refractive index are decreased. Moreover, with increasing the wavelength, the effective refractive index is decreased while and the loss and the effective mode area are increased.
Zohreh Dorrani
Volume 1, Issue 2 , November 2016, Pages 17-22
Abstract
In this paper, we designed a micro-displacement sensor using of two-dimensional photonic crystal structures. This structuer is a hexagonal that on each side located seven holes osilicon. The holes made of air that have been arranged in silicon background. The holes have been arranged in a triangular ...
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In this paper, we designed a micro-displacement sensor using of two-dimensional photonic crystal structures. This structuer is a hexagonal that on each side located seven holes osilicon. The holes made of air that have been arranged in silicon background. The holes have been arranged in a triangular arrangement. In this micro sensor, first by using the finite difference time domain simulation method, optimal values for frequency and lattice constant of photonic crystal were calculated. The intensity of propagating waves was obtained in two micrometers of left side of the structure. In the meantime, the output intensity is as a linear function of the displacement. the sensitivity was obtained as . The values of this structure showed that at a proper operating wavelength, the structure could be used as the micro - displacement sensor that also has very good sensitivity.
The micro - displacement sensor is an important measurement system in many applications such as the micro – electro - mechanical systems, aerospace, structure health monitoring, and many engineering fields.
Ghasem Forozani; malus Mohammadi
Volume 1, Issue 2 , November 2016, Pages 23-32
Abstract
In this article we are going to consider dust acoustic solitary wave in dusty plasma whose constituents are inertial negative charged dust particles, Boltzmann distributed electrons and non-thermal distributed ions with variable dust charge. Using reductive perturbation method, we have obtained Korteweg-de ...
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In this article we are going to consider dust acoustic solitary wave in dusty plasma whose constituents are inertial negative charged dust particles, Boltzmann distributed electrons and non-thermal distributed ions with variable dust charge. Using reductive perturbation method, we have obtained Korteweg-de Veries (kdv) and modified kdv (mkdv) equations. A Sagdeev potential for the system and stability conditions for solitonic solution are also derived.
Mehdi Soodmand
Volume 1, Issue 2 , November 2016, Pages 33-38
Abstract
In this article, the zinc oxide nanowires synthesis into the nanoporous anodic alumina template using the two-step anodization method. The physical properties of zinc oxide nanowires investigated by scanning electron microscopy, X- ray diffraction and energy dispersive X-ray spectroscopy and versus of ...
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In this article, the zinc oxide nanowires synthesis into the nanoporous anodic alumina template using the two-step anodization method. The physical properties of zinc oxide nanowires investigated by scanning electron microscopy, X- ray diffraction and energy dispersive X-ray spectroscopy and versus of electrical resistance with temperature by designing devices. Results show that the zinc oxide nanowires have 66 nm in diameter and 1-6 µm in length, and according to the result of spectroscopies, hexagonal structures (wurtzite) with high purity. Also, Resistance characteristics also vary with substrate temperature and with increasing temperature , the current flowing through the zinc oxide nanowires also increases therefore decreasing resistance.
Motreza Pishbini
Volume 1, Issue 2 , November 2016, Pages 39-44
Abstract
In this investigation by using a hydrochemical simulation the effect of the ambient pressure on the output parameters in Ar single bubble sonoluminescence in water at room temperature has been studied. By considering three dominant instabilities including diffusion, shape and Bjerknes in the phase diagram ...
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In this investigation by using a hydrochemical simulation the effect of the ambient pressure on the output parameters in Ar single bubble sonoluminescence in water at room temperature has been studied. By considering three dominant instabilities including diffusion, shape and Bjerknes in the phase diagram the initial conditions for stable bubble are considered. In addition the intensity of light emission at the moment of collapse is numerically calculated by electron-atom bremsstrahlung, electron-ion bremsstrahlung and radiative recombination. Calculation shows that in good agreement with previous observed evidence the expansion ratio, maximum temperature and emission light intensity are remarkably higher for lower ambient pressure and difference between the maximum and minimum temperature and intensity are about 4000K and 12 orders of magnitude respectively.
Seid Ali Hashemizadeh Oghada; Toher Shaabani; Ahmad Yazdani
Volume 1, Issue 2 , November 2016, Pages 45-54
Abstract
In this research we studied the electronic – crystalline structure in the semiconductor compounds of gallium nitride, aluminum nitride and aluminum gallium nitride, those have spontaneous polarization in 0001 axis and good piezoelectric properties. We used the Wien2k package, which works based ...
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In this research we studied the electronic – crystalline structure in the semiconductor compounds of gallium nitride, aluminum nitride and aluminum gallium nitride, those have spontaneous polarization in 0001 axis and good piezoelectric properties. We used the Wien2k package, which works based on the density functional theory and the Berry’s phase approach to investigate Structural parameters, band gap, Operating and intensity of polarization for aluminum nitride, gallium nitride and aluminum gallium nitride semiconductors. Also, we studied their interaction in replacement of aluminum cation in triple semiconductor of aluminum gallium nitride. The results of the calculations showed that the rate of spontaneous and piezoelectric polarization and total macroscopic polarization in nitride semiconductors is high. We used two concentrations of aluminum as 12.5 and 37.5 percent in the ternary compound of AlxGa1-xN to calculate the polarization. Moreover, our calculations showed, that when the amount of aluminum cations increases, the polarization increases too. We also found that a higher share of the macroscopic polarization is attributed to the spontaneous polarization. In addition to, the spontaneous polarization in this case has a non-linear and quadratic relationship with concentration. Moreover, our calculations for band gap of compounds showed that in all of them the band gap is on Γ axis and straight, when the amount of aluminum cations decreases in AlxGa1-xN, the band gap energy decreases too.
Yousef Yousefi
Volume 1, Issue 2 , November 2016, Pages 55-59
Abstract
We discuss system with non-isotropic non-Heisenberg Hamiltonian with nearest neighbor exchange within a mean field approximation process. We drive equations describing non-Heisenberg non-isotropic model using coherent states in real parameters in general form and then obtain dispersion equations of spin ...
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We discuss system with non-isotropic non-Heisenberg Hamiltonian with nearest neighbor exchange within a mean field approximation process. We drive equations describing non-Heisenberg non-isotropic model using coherent states in real parameters in general form and then obtain dispersion equations of spin wave of dipole and quadrupole branches for a small linear excitation from the ground state. In final, soliton solution for quadrupole branches for these linear equations obtained.