A radiative transfer equation is used to model the diffuse multiple scattering of ultrasound in a medium containing discrete random scatterers. An assumption of uncorrelated phases allows one to write an equation of energy balance for the diffuse intensity. This ultrasonic radiative transfer equation contains single-scattering and propagation parameters that are calculated using the elastic wav...

We consider the problem of scattering of time-harmonic acoustic waves by an unbounded sound-soft rough surface. Recently, a Brakhage–Werner type integral equation formulation of this problem has been proposed, based on an ansatz as a combined singleand double-layer potential, but replacing the usual fundamental solution of the Helmholtz equation with an appropriate half-space Green’s function. ...

tuned liquid dampers (tld) are among passive control devices that have been used to suppress the vibration of structures in recent years. these structures must be adequately presentable as an equivalent single degree of freedom system with long fundamental period. the tld, located at the top floors of the structure, can dissipate the external input energy into the system through the sloshing ef...

The plane-wave dynamics of 3ω → 2ω, ω subharmonic optical parametric oscillators containing a second harmonic generator of the idler-wave ω is analyzed analytically by using the meanfield approximation and numerically by taking into account the field propagation inside the media. The resonant χ(−3ω; 2ω, ω) : χ(−2ω;ω,ω) cascaded second-order nonlinearities induce a mutual injection-locking of th...

Reverse time migration (RTM) is the method of choice for imaging complex subsurface structures. In this paper, we show that slightly modifying the conventional formulation, plus implementing an appropriate imaging condition, yields a true amplitude version of RTM that provides the correct amplitude-versus-angle relation. We also discuss different ways to suppress the migration artifacts and sho...

We propose a hybrid scattering parameter matrix for concurrent on & off – board EMI analysis of mixed RF-Digital Circuits. To start with, we first consider on–board EMI effects on digital circuits, particularly on an inverter to show the vulnerability of digital devices to RF interference and investigate both system and device level upsets due to adjacent EMI sources on Printed Circuit Boards (...

W e study the variations of the received frequencies (Complex Doppler effect) from a source moving uniformly in a homogeneous isotropic plasma and emitting a uniform EM plane wave with amplitude E0 , as a function of coe/Eo where coe is the plasma frequency. The ratio of the velocity U of the source over the group velocity UgT of the transmitted wave is then calculated from the slope of the Dop...

An algorithm for the direct inversion of the linear systems arising from Nyström discretization of integral equations on one-dimensional domains is described. The method typically has O(N) complexity when applied to boundary integral equations (BIEs) in the plane with non-oscillatory kernels such as those associated with the Laplace and Stokes’ equations. The scaling coefficient suppressed by t...

We investigate the scattering of plane harmonic compression and shear waves by a Griffith crack in an infinite isotropic dielectric polymer. The dielectric polymer is permeated by a uniform electric field normal to the crack face, and the incoming wave is applied in an arbitrary direction. By the use of Fourier transforms, we reduce the problem to that of solving two simultaneous dual integral ...

High-order harmonic generation (HHG) from aligned molecules has provided a promising way to probe the molecular orbital with an Ångström resolution. This method, usually called molecular orbital tomography (MOT) replies on a simple assumption of the plane-wave approximation (PW), which has long been questioned due to that PW approximation is known to be valid in the keV energy region. However, ...