نتایج جستجو برای: dispersion wave

تعداد نتایج: 273423  

A theory is presented for the dispersion relations of the nonlinear phonon-polaritons arising when phonons are coupled to the electromagnetic waves in multilayered structures of nonlinear materials. The calculations are applied to a multilayered structure consisting of a thin film surrounded by semi-infinite bounding media where each layer may have a frequency dependent dielectric function and ...

A Mandi, P Chandra Pal P Pati S Kundu

In this work, attempts are made to study the dispersion of Love waves in dry sandy layer sandwiched between fiber reinforced layer and inhomogeneous half space.Inhomogeneity in half space associated with density and rigidity and considered in exponential form. Displacement components for fiber reinforced layer, dry sandy layer and inhomogeneous half-space have been obtained by using method of s...

2011
NI Oguanobi BJC Onwubere SO Ike BC Anisiuba EC Ejim OG Ibegbulam

BACKGROUND The prognostic implications of P-wave dispersion in patients with a variety of cardiac disease conditions are increasingly being recognised. The relationship between P-wave dispersion and left ventricular function in sickle cell anaemia is unknown. OBJECTIVE This study was aimed at evaluating the relationship between P-wave dispersion and left ventricular function in adult Nigerian...

D.K Madan R.K Poonia V Kaliraman,

The propagation of surface waves in a fluid- saturated porous isotropic layer over a semi-infinite homogeneous elastic medium with an irregularity for free and rigid interfaces have been studied. The rectangular irregularity has been taken in the half-space. The dispersion equation for Love waves is derived by simple mathematical techniques followed by Fourier transformations.  It can be seen t...

Journal: :international journal of civil engineering 0
m. fazlavi n. 21, arghavan, dibaji shomali, farmanieh, tehran e. haghshenas n. 21, arghavan, dibaji shomali, farmanieh, tehran

in this paper we are going to show the importance of mode identification in microtremor array analysis. the idea come from four concentric ambient noise array recordings with aperture 100 to 1000 meters, performed in southern urban area of tehran near the shrine of imam khomeini. these measurements were part of a comprehensive research project with the aim of determination of deep shear wave ve...

P Alam, S Kundu

In the present paper, we are contemplating the influences of heterogeneities and pre-stresses on the propagation of Love-type waves in an initially stressed heterogeneous transversely isotropic layer of finite thickness lying over an inhomogeneous half space. The material constants and pre-stress have been taken as space dependent and arbitrary functions of depth in the respective media. To sim...

تشکری, حسن, نجاتی, عاطفه, کنجوری, فرامرز,

In this work, we calculated the phonon dispersion of GaNNTs (4,0) and (4,4) by quantum ESPRESSO package using Density Functional Theory (DFT), pseudo potentials, and plane wave self-consistent field (PWscf) method. For the purpose of lattice-dynamical calculation and phononic properties, we used PWscf and Phonon codes. The former produces the self-consistent electronic and all related computati...

Journal: :MEDICC review 2014
Elibet Chávez Emilio González María del Carmen Llanes Merlin Garí Yosvany García Julieta García Elizabet Fernández

INTRODUCTION Hypertension and obesity in adults have been linked to increased EKG P-wave dispersion; the association has been shown in relation to hypertension, left ventricular hypertrophy and atrial enlargement. Though studies in children have linked P-wave dispersion to left ventricular hypertrophy, scant pediatric literature relates P-wave dispersion to hypertension and obesity. OBJECTIVE...

Journal: :فیزیک زمین و فضا 0
الهام شعبانی دانشجوی دکتری ژئوفیزیک، گروه فیزیک زمین، مؤسسة ژئوفیزیک دانشگاه تهران نوربخش میرزائی دانشیار، گروه فیزیک زمین، مؤسسة ژئوفیزیک دانشگاه تهران ابراهیم حق شناس استادیار، پژوهشگاه بین المللی زلزله شناسی و مهندسی زلزله، تهران مرتضی اسکندری قادی دانشیار، گروه علوم پایه مهندسی، پردیس دانشکده های فنی، دانشگاه تهران

recordings of ambient noise or microtremors are increasingly used to find valuable information on soil in one dimension at a given site. ambient vibrations, which are assumed to be mainly composed of surface waves, can be used to determine the surface wave dispersion curve in order to retrieve shear wave velocity profile. in this regard, microtremors are usually recorded simultaneously in an ar...

Journal: :Journal of the American College of Cardiology 1995
M Zabel S Portnoy M R Franz

OBJECTIVES This study tested the correlation of QT and JT dispersion and other potentially useful electrocardiographic (ECG) indexes with dispersion of repolarization and recovery time. BACKGROUND Dispersion of ventricular repolarization is currently being assessed noninvasively from the surface ECG by means of QT and JT dispersion, although their correlation with dispersion of repolarization...

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