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The transverse ultrasound absorption in cubic crystals with positive and negative anisotropies of the second-order elasticity moduli is analyzed. The scattering of the ultrasound by defects and during anharmonic scattering processes is…

Materials Science · Physics 2007-05-23 I. G. Kuleyev , I. I. Kuleyev , I. Yu. Arapova

By taking both the Doppler frequency shift for electromagnetic wave and the quantum energy variation of matter wave into consideration, a resonant-absorption condition based on the local-ether wave equation is presented to account for a…

General Physics · Physics 2007-05-23 Ching-Chuan Su

Particulate materials include powders, emulsions, composites, and many others. This is why measuring these has become important for both industry and scientific applications. For industrial applications, the greatest need is to measure…

Statistical Mechanics · Physics 2024-07-10 Paulo S. Piva , Kevish K. Napal , Art L. Gower

Lying between traditional parabolic and hyperbolic equations, time-fractional wave equations of order $\alpha\in(1,2)$ in time inherit both decaying and oscillating properties. In this article, we establish a long-time asymptotic estimate…

Analysis of PDEs · Mathematics 2024-01-05 Xinchi Huang , Yikan Liu

A popular absorbing structure, often referred to as Perfect Metamaterial Absorber, comprising metallic periodic pattern over a thin low-loss grounded substrate is studied by resorting to an efficient transmission line model. This approach…

Classical Physics · Physics 2015-06-12 Filippo Costa , Simone Genovesi , Agostino Monorchio , Giuliano Manara

The influence of absorption on the spectra of microwave graphs has been studied experimentally. The microwave networks were made up of coaxial cables and T junctions. First, absorption was introduced by attaching a 50 Ohm load to an…

Chaotic Dynamics · Physics 2014-04-01 M. Allgaier , S. Gehler , S. Barkhofen , H. -J. Stöckmann , U. Kuhl

High-efficiency absorption of low-frequency sounds (< 1000 Hz) while maintaining a free flow of fluids remains a significant challenge in acoustical engineering due to the rigid trade-off between absorption and ventilation performances.…

Applied Physics · Physics 2020-06-01 Xiao Xiang , Xiaoxiao Wu , Xin Li , Peng Wu , Hong He , Qianjin Mu , Shuxia Wang , Yingzhou Huang , Weijia Wen

We study theoretically the mode conversion and the associated resonant absorption of p-polarized electromagnetic waves into longitudinal plasma oscillations in cold, unmagnetized and stratified plasmas with periodic spatial density…

Plasma Physics · Physics 2016-04-05 Dae Jung Yu , Kihong Kim

Consider a particle which is randomly accelerated by Gaussian white noise on the line segment $0<x<1$ and is absorbed as soon as it reaches $x=0$ or $x=1$. The mean absorption time $T(x,v)$, where $x$ and $v$ denote the initial position and…

Statistical Mechanics · Physics 2011-07-19 Stanislav N. Kotsev , Theodore W. Burkhardt

We address the issue of whether amplification, like absorption, suppresses wave transmission at large gain, as has been claimed in previous studies of wave propagation in active random media. A closer examination reveals that the…

Disordered Systems and Neural Networks · Physics 2009-10-31 Xunya Jiang , Qiming Li , C. M. Soukoulis

Absorption and emission of light is studied theoretically for excited atoms in coherent superposition of states subjected to isolated attosecond pulses in the extreme ultraviolet range. A gauge invariant formulation of transient absorption…

Atomic Physics · Physics 2023-05-24 Axel Stenquist , Felipe Zapata , Jan Marcus Dahlström

In photoacoustic imaging, ultrasound waves generated by a temperature rise after illumination of light absorbing structures are measured on the sample surface. These measurements are then used to reconstruct the optical absorption. We…

Applied Physics · Physics 2018-12-05 Oliver Lang , Peter Kovacs , Christian Motz , Mario Huemer , Thomas Berer , Peter Burgholzer

With the development of terahertz time-domain spectroscopy, methods have been proposed to precisely estimate the thickness, refractive index, and attenuation coefficient of a sample. In this article, we propose a new method to compute these…

In this paper, we consider a long-wave equivalent medium to a finely parallel-layered inhomogeneous medium, obtained using the Backus average. Following the work of Postma and Backus, we show explicitly the derivations of the conditions to…

Geophysics · Physics 2018-09-28 F. P. Adamus

We study the dominant effect of a long wavelength density perturbation $\delta(\lambda_L)$ on short distance physics. In the non-relativistic limit, the result is a uniform acceleration, fixed by the equivalence principle, and typically has…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-27 Tobias Baldauf , Mehrdad Mirbabayi , Marko Simonović , Matias Zaldarriaga

It is shown that perfect absorption and giant amplification can be realized when a wave impinges on a special metamaterial layer with zero real parts of the permittivity and permeability. The imaginary parts of the permittivity and…

Optics · Physics 2011-05-26 Y. Jin , S. S. Xiao , N. A. Mortensen , S. L. He

Sound wave propagation in a relativistic perfect fluid with a non-homogeneous isentropic flow is studied in terms of acoustic geometry. The sound wave equation turns out to be equivalent to the equation of motion for a massless scalar field…

General Relativity and Quantum Cosmology · Physics 2009-10-31 Neven Bilic

We investigate the interaction of polarized electromagnetic waves with hyperbolic metamaterial structures, whereby the in-plane permittivity component $\epsilon_x$ is opposite in sign to the normal component $\epsilon_z$. We find that when…

Optics · Physics 2015-06-19 Klaus Halterman , J. Merle Elson

Signatures of photon localization are observed in a constellation of transport phenomena which reflect the transition from diffusive to localized waves. The dimensionless conductance, g, and the ratio of the typical spectral width and…

Disordered Systems and Neural Networks · Physics 2009-11-11 A. Z. Genack , A. A. Chabanov

It is shown that the dispersion and attenuation functions in a linear viscoelastic medium with a positive relaxation spectrum have a sublinear growth rate at very high frequencies. A local dispersion relation in parametric form is found.…

Mathematical Physics · Physics 2015-05-18 Malgorzata Seredynska , Andrzej Hanyga