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Search Results: 1 - 10 of 66 matches for " Abdolrasoul Gharaati;Hadis Azarshab "
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Characterization of Defect Modes in Onedimensional Ternary Metallo-Dielectric Nanolayered Photonic Crystal
Abdolrasoul Gharaati;Hadis Azarshab
PIER B , 2012, DOI: 10.2528/PIERB11101410
Abstract: We investigate the characterization of defect modes in one-dimensional ternary symmetric metallo-dielectric photonic crystal (1DTSMDPC) band-gap structures. We consider the defect modes for symmetric model with respect to the defect layer. We demonstrate reflectance with respect to the wavelength and its dependence on different thicknesses and indices of refraction of dielectric defect layer, angle of incidence and number of periods for both transverse electric (TE) and transverse magnetic (TM) waves. Also, we investigate properties of the defect modes for different metals. Our findings show that the photonic crystal (PC) with defect layer, made of two dielectrics and one metallic material, leads to different band-gap structures with respect to one dielectric and one metallic layer. There is at least one defect mode when we use dielectric or metallic defect layer in symmetric structure. And, the number of defect modes will be increased by the enhancement of refractive index and thickness of dielectric defect layer.
Photonic Band Structures and Enhancement of Omnidirectional Reflection Bands by Using a Ternary 1D Photonic Crystal Including Left-Handed Materials
Abdolrasoul Gharaati;Z. Zare
PIER M , 2011, DOI: 10.2528/PIERM11070711
Abstract: In this paper, we use the Bloch theorem and transfer matrix method to calculate the dispersion relation of a ternary 1D photonic crystal with left-handed materials. Then, we obtain the total omnidirectional reflection band gaps of this structure. We demonstrate that the omnidirectional reflected frequency bands are enlarged in comparison with ordinary materials with positive index of refraction.
Analytical Calculation of Band Gap of a 1D Planar Ternary Photonic Crystal by Simulating with a Symmetric Lossless Transmission Line
Abdolrasoul Gharaati;Alireza Serajfard
PIER Letters , 2012, DOI: 10.2528/PIERL11102007
Abstract: We simulate a 1D ternary photonic crystal (TPC) employed as a clad of a photonic crystal waveguide (PCW) which consists three different lossless dielectric layers as a unit-cell. Calculating input impedance at each layer interface and using a lossless reciprocal transmission line as a model, we can predict angle intervals in which reflection occurs due to photonic crystal effect. Comparing this method with transfer matrix method and bang structure shows perfect agreement.
Band Structure Engineering in 2D Photonic Crystal Waveguide with Rhombic Cross-Section Elements
Abdolrasoul Gharaati,Sayed Hasan Zahraei
Advances in Optical Technologies , 2014, DOI: 10.1155/2014/780142
Abstract: Two-dimensional photonic crystal (2D PhC) waveguides with square lattice composed of dielectric rhombic cross-section elements in air background, by using plane wave expansion (PWE) method, are investigated. In order to study the change of photonic band gap (PBG) by changing of elongation of elements, the band structure of the used structure is plotted. We observe that the size of the PBG changes by variation of elongation of elements, but there is no any change in the magnitude of defect modes. However, the used structure does not have any TE defect modes but it has TM defect mode for any angle of elongation. So, the used structure can be used as optical polarizer. 1. Introduction PhCs are class of media represented by natural or artificial structures with periodic modulation of the refractive index [1–3]. Such optical media have some peculiar properties which gives an opportunity for a number of applications to be implemented on their basis. In 2D PhCs, the periodic modulation of the refractive index occurs in two directions, while in one other direction structure is uniform. When the refractive index contrast between elements of the PhC and background is high enough, a range of frequencies exists for which propagation is forbidden in the PhC and called photonic band gap (PBG). The PBG depends upon the arrangement and shape of elements of the PhC, fill factor, and dielectric contrast of the two mediums used in forming PhC. The most important feature of PhCs is ability to support spatially electromagnetic localized modes when a perfectly periodic PhC has spatial defects [4–6]. In recent years, a lot of researches are devoted to study 2D PhC with circular, square, and elliptic cross-section elements [7, 8]. However, less work was devoted to study of PhC with rhombic cross-section elements. In this paper, we study band structure for 2D PhC waveguide with dielectric rhombic cross-section elements with a square lattice and how band structure is affected by elongating of elements. 2. PWE Method and Numerical Analysis We consider 2D PhC waveguide as shown in Figure 1(a), consisting of a square lattice of GaAs rhombic cross-section elements in air background, having a lattice constant of ?nm. The rhombuses have side and a refractive index of [8]. The waveguide core is formed by substitution of a row of rhombuses with a row of different rhombuses with refractive index and side along the direction. Figure 1(b) shows the unit cell for the structure used which is composed of the elements as shown in Figure 1(c) [1]. Figure 1: (a) 2D PhC waveguide, (b) the unit
Diabetic diagnose test based on PPG signal and identification system  [PDF]
Hadis Karimipour, Heydar Toossian Shandiz, Edmond Zahedi
Journal of Biomedical Science and Engineering (JBiSE) , 2009, DOI: 10.4236/jbise.2009.26067
Abstract: In this paper, photoplethysmogram (PPG) signals from two classes consisting of healthy and diabetic subjects have been used to estimate the parameters of Auto-Regressive Moving Average (ARMA) models. The healthy class consists of 70 healthy and the diabetic classes of 70 diabetic patients. The estimated ARMA parameters have then been averaged for each class, leading to a unique representative model per class. The order of the ARMA model has been selected as to achieve the best classification. The resulting model produces a specificity of %91.4 and a sensitivity of, %100. The proposed technique may find applications in determining the diabetic state of a subject based on a non-invasive signal.
Evaluation of Unsaturated Layer Effect on Seismic Analysis of Unbraced Sheet Pile Wall  [PDF]
Mohammad Hossein Jahangir, Hadis Soleymani, Saeideh Sadeghi
Open Journal of Marine Science (OJMS) , 2017, DOI: 10.4236/ojms.2017.72022
Abstract: This paper is built upon the previous developments on lateral earth pressure by providing a series of analytical expressions that may be used to evaluate vertical profiles of the effective stress and the corresponding suction stress under steady-state flow conditions. Suction stress profile is modeled for one layer sand near the ground above the water level under hydrostatic conditions. By definition, the absolute magnitude of suction stress depends on both the magnitude of the effective stress parameter and matric suction itself. Thus, by developing the Rankine’s relations in seismic state, the composing method of active and passive surfaces in sides of unbraced sheet pile is examinated and the effects of soil parameter on those surfaces are evaluated by a similar process. The relations described the quantitative evaluation of lateral earth pressure on sheet pile and the effects of unsaturated layer on bending moment and embedded depth of sheet pile in soil.
Extreme Points of the Unit Ball in the Dual Space of Some Real Subspaces of Banach Spaces of Lipschitz Functions
Davood Alimohammadi,Hadis Pazandeh
ISRN Mathematical Analysis , 2012, DOI: 10.5402/2012/735139
Linear Isometries between Real Banach Algebras of Continuous Complex-Valued Functions
Davood Alimohammadi,Hadis Pazandeh
Journal of Operators , 2013, DOI: 10.1155/2013/506129
Abstract: Let and be compact Hausdorff spaces, and let and be topological involutions on and , respectively. In 1991, Kulkarni and Arundhathi characterized linear isometries from a real uniform function algebra on ( , ) onto a real uniform function algebra on ( , ) applying their Choquet boundaries and showed that these mappings are weighted composition operators. In this paper, we characterize all onto linear isometries and certain into linear isometries between and applying the extreme points in the unit balls of and . 1. Introduction and Preliminaries Let and denote the field of real and complex numbers, respectively. The symbol denotes a field that can be either or . The elements of are called scalars. We also denote by the set of all with . Let be a normed space over . We denote by and the dual space of and the closed unit ball of , respectively. For a subset of , let denote the set of all extreme points of . Kulkarni and Limaye showed [1, Theorem 2] that if is a nonzero linear subspace of and , then has an extension to some . We know that if and are normed spaces over and is a linear isometry from onto over , then is a bijection mapping between and . Let be a compact Hausdorff space. We denote by the unital commutative Banach algebra of all continuous functions from into , with the uniform norm , . We write instead as . For , we consider the linear functional on defined by ( ), which is called the evaluation functional on at . Clearly, for all . It is known [2, page 441] that Let be a real or complex linear subspace of . A nonempty subset of is called a boundary for (with respect to ), if for each the function assumes its maximum on at some . We denote by the intersection of all closed boundaries for . If is a boundary for , it is called the Shilov boundary for (with respect to ). Let be linear subspace of containing , the constant function with value on . A representing measure for is an -valued regular Borel measure on such that for all . Let . If , then and , the point mass measure on at , is a representing measure for . We denote by the set of all for which is the only representing measure for . If is a boundary for , it is called the Choquet boundary for (with respect to ). We know that Let be a real linear subspace of , and let be nonempty subset of . We say that is extremely regular at if for every open neighborhood of and for each there is a function with such that for all and for all . Let be a nonempty set. A self-map is called an involution on if for all . A subset of is called -invariant if . Clearly, if is -invariant, then . A -invariant
A Quantitative Model for Measuring the Project and Feeding Buffers in CCM Method by Fuzzy Approach (Case Study: Construction of Industrial Wastewater Treatment Unit at Lorestan Petrochemical Company, Iran)
Hadis Yaghoubzadeh,Emad Roghanian
International Journal of Engineering Research , 2014,
Abstract: The non-completion of a project within a planned duration is one of the greatest problems for organizations in the process of its execution. This issue may cause problems such as increasing the variable costs of the project compared to the predicted figure or its delayed delivery to the
Plexiform Neurofibroma of Penis
Hamid Mazdak,Mohammad Reza Gharaati
Urology Journal , 2007,
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