TM plasmons in a cylindrical superlattices (LANS) waveguide structure

In this work, we have investigated theoretically the propagation characteristics of TM plasmons in a cylindrical wave-guide structure of a lateral antiferromagnetic - non magnetic superlattices (LANS) bounded by a metal. We derived the Eigenmodes equation and study the dispersion properties of transverse magnetic (TM) plasmons which propagate on the waveguide. We found that, backward TM plasmons can be tuned by adjusting the thickness of the waveguide to small reduced radius. We also found that the plasmons turn from backward to forward when the bounded material is vacuum. We also illustrated the dependence of the wave index nx on the magnetic fraction f1 of (LANS). Larger propagation lengths of TM plasmons are realized at small reduced radius and less magnetic material in LANS. The energy flow on the waveguide is also analyzed. We studied the dependence of the power flow on the electric permittivity of the metal m. More forward plasmons are observed by increasing Em. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2299

Test of Universality in Anisotropic 3D Ising Model

Chen and Dohm predicted theoretically in 2004 that the widely believed universality principle is violated in the Ising model on the simple cubic lattice with more than only six nearest neighbours. Schulte and Drope by Monte Carlo simulations found such violation, but not in the predicted direction. Selke and Shchur tested the square lattice. Here we check only this universality for the susceptibility ratio near the critical point. For this purpose we study first the standard Ising model on a simple cubic lattice with six nearest neighbours, then with six nearest and twelve next-nearest neighbours, and compare the results with the Chen-Dohm lattice of six nearest neighbours and only half of the twelve next-nearest neighbours. We do not confirm the violation of universality found by Schulte and Drope in the susceptibility ratio.Comment: 6 pages including 4 figures, Physica A, in pres

New Eaxactly Solvable Hamiltonians: Shape Invariance and Self-Similarity

We discuss in some detail the self-similar potentials of Shabat and Spiridonov which are reflectionless and have an infinite number of bound states. We demonstrate that these self-similar potentials are in fact shape invariant potentials within the formalism of supersymmetric quantum mechanics. In particular, using a scaling ansatz for the change of parameters, we obtain a large class of new, reflectionless, shape invariant potentials of which the Shabat-Spiridonov ones are a special case. These new potentials can be viewed as q-deformations of the single soliton solution corresponding to the Rosen-Morse potential. Explicit expressions for the energy eigenvalues, eigenfunctions and transmission coefficients for these potentials are obtained. We show that these potentials can also be obtained numerically. Included as an intriguing case is a shape invariant double well potential whose supersymmetric partner potential is only a single well. Our class of exactly solvable Hamiltonians is further enlarged by examining two new directions: (i) changes of parameters which are different from the previously studied cases of translation and scaling; (ii) extending the usual concept of shape invariance in one step to a multi-step situation. These extensions can be viewed as q-deformations of the harmonic oscillator or multi-soliton solutions corresponding to the Rosen-Morse potential.Comment: 26 pages, plain tex, request figures by e-mai

Проектування та аналіз хвилеводного датчика структури на основі наночастинок і лівогвинтового матеріалу

Використання лівогвинтових матеріалів у наукових застосуваннях привернуло увагу багатьох дослідників за останні кілька років. Наночастинки – це також нові матеріали з невеликими розмірами в нанометровому масштабі, які швидко привертають до себе все більший інтерес і увагу, особливо в галузі нанотехнологій. Основними перевагами використання як лівогвинтових матеріалів, так і наночастинок у запропонованих датчиках є можливість значного зменшення розмірів структури та покращення датчика чутливості. У роботі ми дослідили тришаровий планарний хвилеводний датчик, що складається з ядра з тонких наночастинок на основі лівосторонніх матеріалів підкладки та водяного покриву, які використовуються для зондування. Взаємодія поверхневих хвиль ТМ і ТЕ з запропонованою планарною хвилеводною структурою буде вивчатися для виявлення глибини проникнення; будь-які зміни показника заломлення аналіту та пов'язаного з цим ефекту підвищення чутливості будуть проаналізовані. Спостерігається, що чутливість запропонованих датчиків покращується у порівнянні із звичайними тришаровими хвилеводними датчиками. Помічено високу чутливість, яка може бути використана для майбутніх застосувань датчиків.The use of left-handed materials in scientific applications has attracted attention of many researchers in the last few years. Nanoparticles are also new materials with small size in scale of nanometer which are rapidly attracting more interest and consideration especially in nanotechnology application. The main advantages of using both left-handed materials and nanoparticles in the proposed sensors are the possibility of a significant reduction in the structure size and the enhancement of the sensitivity sensor. In this paper, we have investigated a three-layer planar waveguide sensor consisting of thin nanoparticles core based on left-handed material substrate and water cover which are employed for sensing applications. The interaction of TM and TE surface waves with the proposed planar waveguide structure will be studied for detection of the penetration depth, any changes in the refractive index of the analyte and the related sensitivity enhancement effect are analyzed. It is observed that the sensitivity of the proposed sensors is improved compared to that of the conventional three-layer waveguide sensors. High sensitivity has been observed which could be utilized for future sensor applications

Angled local directional pattern for texture analysis with an application to facial expression recognition

Local binary pattern (LBP) is currently one of the most common feature extraction methods used for texture analysis. However, LBP suffers from random noise, because it depends on image intensity. Recently, a more stable feature method was introduced, local directional pattern (LDP) uses the gradient space instead of the pixel intensity. Typically, LDP generates a code based on the edge response values using Kirsch masks. Yet, despite the great achievement of LDP, it has two drawbacks. The first is the static choice of the number of most significant bits used for LDP code generation. Second, the original LDP method uses the 8‐neighborhood to compute the LDP code, and the value of the centre pixel is ignored. This study presents angled local directional pattern (ALDP), which is an improved version of LDP, for texture analysis. Experimental results on two different texture data sets, using six different classifiers, show that ALDP substantially outperforms both LDP and LBP methods. The ALDP has been evaluated to recognise the facial expressions emotion. Results indicate a very high recognition rate for the proposed method. An added advantage is that ALDP has an adaptive approach for the selection of the number significant bits as opposed to LDP

Characteristics of electomagnetic and magneto-static surface waves in metal-dielectric-ferrite-left handed waveguide layered structure

Some works have been carried out on studying metamaterials with negative electrical permittivity and negative magnetic permeability which called Left-handed materials (LHM), the propagation dispersion characteristics of magnetic waves in waveguide structures containing LHM. In this communication, we investigate the dispersion characteristics of magnetic surface waves in a metal-dielectric-ferrite (YIG)-LHM layered waveguide structure. Several characteristics of the propagation are also obtained especially on the non-reciprocal behavior. It has been noticed that the non-reciprocal behavior of the wave propagation has been obtained in the forward direction for the electromagnetic waves whereas this reciprocal behavior has been found in the forward and backward directions for the magneto-static surface waves. It should be stressed that the addition of the LHM layer to the above waveguide structure has been noticed to dominate the control of the direction of the dispersion curves from forward to backward wave propagation

Design and characterization of homogeneous TM nonlinear wave guide sensors

Consiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7 , Rome / CNR - Consiglio Nazionale delle RichercheSIGLEITItal