The problem of inverse scattering of a plane acoustic wave by a penetrable scatterer with the transmission boundary condition is studied. It is proved that, if the constant exterior wavenumber is known, then the shape of the obstacle and the constant transmission parameter and the constant interior wavenumber are uniquely determined by the scattering amplitude known at the constant exterior wav...

The waveguide invariant is typically defined using of normal modes or ray theory, but it can also be related to the wavenumber-integration method for calculating the acoustic field in a waveguide. In this letter, the Wiener-Khinchin Theorem is used to show that the autocorrelation of the wavenumber-integration kernel, when plotted versus wavenumber difference and frequency, contains striations ...

Reverse time migration backscattering contains kinematic information that can be used to constrain velocity models. The backscattering results from the correlation between forward scattered and backscattered wavefields from sharp interfaces, i.e., sediment-salt interfaces. The synchronization between these wavefields depends on the velocity of the sediment section and the correct interpretation...

An analytical wavepacket-based jet noise model has been applied for the first time to highperformance, military aircraft noise. Ground-based acoustical measurements were made of a tethered high-performance military aircraft with one engine cycling through four engine conditions. The resulting spectra have been decomposed into fine and large-scale similarity spectral components. The spatial dist...

Real-time Raman spectroscopy can be used to assist in assessing skin lesions suspicious for cancer. Most of the diagnostic algorithms are based on full band of the Raman spectra, either in the fingerprint region or the high wavenumber region. In this paper we explored wavenumber selection based analysis in Raman spectroscopy for skin cancer diagnosis. Wavenumber selection was implemented using ...

This paper presents a three-dimensional (3D) range migration algorithm (RMA) suitable for downward-looking 3D-SAR with single-transmitting and multiple-receiving linear array antennas (STMR-LAA). As the round-trip range equation in 3D-SAR with STMR-LAA is a dual square root, the signal spectrum in 3D wavenumber domain contains nonlinear phase terms besides constant and linear phase terms. In th...

The effects of ambipolar diffusion on the linear stability of weakly ionised accretion discs are examined. Earlier work on this topic has focused on axial magnetic fields and perturbation wavenumbers. We consider here more general field and wavenumber geometries, and find that qualitatively new results are obtained. Provided a radial wavenumber and azimuthal field are present along with their a...