The effect of a surface impedance load on the behavior of quasi-Rayleigh waves near a cylindrical cavityPleiades Publishing Ltd - Tập 56 - Trang 422-428 - 2010
V. V. Tyutekin, D. E. Syresin, T. V. Zharnikov
The effect of a surface impedance load on the properties of axisymmetric quasi-Rayleigh waves propagating along the boundaries of a cylindrical cavity is investigated. By solving the problem by means of the impedance method, a dispersion equation for these waves is obtained. It is shown that the equation can be represented as the condition that the determinant of the sum of impedance matrices of t...... hiện toàn bộ
Reconstruction of the fine structure of an acoustic scatterer against the distorting influence of its large-scale inhomogeneitiesPleiades Publishing Ltd - Tập 49 - Trang 627-637 - 2003
V. A. Burov, I. M. Grishina, O. I. Lapshenkina, S. A. Morozov, O. D. Rumyantseva, E. G. Sukhov
In the ultrasonic diagnostics of small-size neoplasms of biological tissues at the earliest stage of their development, an efficient way to eliminate the distorting influence of high-contrast or large inhomogeneities of the biological medium is to apply the iterative technique. A simple approach is proposed, which makes it possible with only two iteration steps to achieve an efficient focusing of ...... hiện toàn bộ
High-frequency modes in a two-dimensional rectangular room with windowsPleiades Publishing Ltd - Tập 56 - Trang 525-536 - 2010
E. D. Shabalina, N. V. Shirgina, A. V. Shanin
We examine a two-dimensional model problem of architectural acoustics on sound propagation in a rectangular room with windows. It is supposed that the walls are ideally flat and hard; the windows absorb all energy that falls upon them. We search for the modes of such a room having minimal attenuation indices, which have the expressed structure of billiard trajectories. The main attenuation mechani...... hiện toàn bộ
Study of how hydrological conditions affect the propagation of pseudorandom signals from the shelf in deep waterPleiades Publishing Ltd - Tập 62 - Trang 350-356 - 2016
Yu. N. Morgunov, V. V. Bezotvetnykh, A. V. Burenin, E. A. Voitenko
The paper examines how hydrological conditions affect manifestation of the acoustic “landslide” effect, which consists in focusing of acoustic energy in the near-bottom layer on the shelf and its transition to the axis of an underwater sound channel in deep water. We compare the results of experiments performed in the Sea of Japan in April 2014 and August 2006 on the same acoustic track, where the...... hiện toàn bộ
Adaptive resolution of broadband hydroacoustic signals with partially coherent structurePleiades Publishing Ltd - Tập 59 - Trang 565-579 - 2013
G. S. Malyshkin, A. V. Shafranyuk
The problem of resolving a weak broadband signal against the background of a strong broadband signal using adaptive superresolution algorithms for signals with distorted coherence is considered. The correlation matrix is estimated using not only time but also frequency accumulation with a differently formed focusing matrix. Imitative simulation has been carried out and the simulation results are a...... hiện toàn bộ
Common features of the amplitude-frequency characteristics of vowels in different forms of speechPleiades Publishing Ltd - Tập 48 - Trang 620-622 - 2002
N. G. Andreeva, G. A. Kulikov, A. P. Samokishchuk
According to classical concepts, the relationship between the first two formants is the feature that determines the identification of long vowels in speech. However, the characteristics of vowels may considerably vary depending on the conditions of their production. Thus, the aforementioned features that are valid for adult speech cannot be extended to speech signals with high fundamental frequenc...... hiện toàn bộ