نتایج جستجو برای: acoustic wave scattering

تعداد نتایج: 390724  

2002
A G Ramm

Modified Rayleigh conjecture (MRC) in scattering theory is proposed and justified. MRC allows one to develop numerical algorithms for solving direct scattering problems related to acoustic wave scattering by soft and hard obstacles of arbitrary shapes. It gives an error estimate for solving the direct scattering problem. It suggests a numerical method for finding the shape of a star-shaped obst...

2007
F. M. Bufler

A simplified model for inelastic acoustic phonon scattering of holes in silicon is developed. It consists in approximating both the acoustic phonon energy and the square of the phonon wave vector by lattice-temperature dependent constants. The resulting scattering rate depends only on energy and thus facilitates the search of after-scattering-states during full-band Monte Carlo simulation. The ...

Journal: :Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics 1999
C Coste F Lund M Umeki

When a surface wave interacts with a vertical vortex in shallow water the latter induces a dislocation in the incident wave fronts that is analogous to what happens in the Aharonov-Bohm effect for the scattering of electrons by a confined magnetic field. In addition to this global similarity between these two physical systems there is scattering. This paper reports a detailed calculation of thi...

2007
A. G. Ramm

Acoustic or electromagnetic EM wave scattering by one or several bodies is usually studied by reducing the problem to solving some integral equations. In this paper we show that if the bodies are small in comparison with the wavelength, then the scattering problem can be reduced to solving linear algebraic systems with matrices whose elements have physical meaning. These elements are electrical...

2001
RAINER KRESS R. KRESS

We first review the basic existence results for exterior boundary value problems for the Helmholtz equation via boundary integral equations. Then we describe the numerical solution of these integral equations in two dimensions for a smooth boundary curve using trigonometric polynomials on an equidistant mesh. We provide a comparison of the NystrGm method, the collocation method and the Gale&in ...

Journal: :Physical review letters 2005
Kikuo Cho Kazunori Okumoto N I Nikolaev A L Ivanov

Bragg scattering of polaritons by a coherent acoustic wave is mediated and strongly enhanced by the exciton states resonant with the acoustic and optic fields in the intraband and interband transitions, respectively. In this case, in contrast with conventional acousto-optics, the resonantly enhanced Bragg spectra reveal the multiple orders of diffracted light. For polaritons in GaAs microcaviti...

2012
H. Arabshahi A. Karimi

In this work the electron mobility of AlN Wurtzite and AlN Zincblende semiconductor compounds were calculated using iterative method in range of 100-600 K. We compare polar optic phonon scattering, deformation-potential acoustic phonon scattering, piezoelectric scattering and impurity scattering mechanisms. Boltzmann transport equation was solved using iterative method. In addition, we took int...

Journal: :iranian journal of public health 0
m shayeghi dept. of medical entomology and vector control, school of public health, tehran mh dehghani dept. of environmental health engineering, school of public health, tehran university of medical sci am fadaei dept. of environmental health engineering, school of public health, tehran university of medical sci

background: organophosphorus pesticides are one of the most prevalent usages for pest control in the country. such pesti­cides enter into water sources by different routes. since drinking of contaminated water at the higher doses than the standard level, may causes undesirable effects to human health and ecosystem. the object of this research was to investigate the ef­fect of various parameters...

2016
Christopher M. Kube Joseph A. Turner

An elastic wave propagating in a metal loses a portion of its energy from scattering caused by acoustic impedance differences existing at the boundaries of anisotropic grains. Theoretical scattering models capture this phenomena by assuming the incoming wave is described by an average elastic moduli tensorC0 i jkl (x) that is perturbed by a grain with elasticityCi jkl (x ′) where the scattering...

Journal: :international journal of environmental research 2012
a.r. noorpoor a. sadighzadeh h. habibnejad

the removal of fine particles less than 2.5 μm in diameter generated from industrial plantsrepresents a serious challenge in air pollution abatement. these particles can penetrate deeply into the lungs and are difficult to remove by cyclones, electrostatic precipitators, and other conventional separation devices. in this paper, the influence of acoustic waves on removing aerosol particles from ...

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