Results 261 to 270 of about 2,036,069 (311)

Wideband acoustic transmission of human lungs

Medical & Biological Engineering & Computing, 1989
The measurement of sound transmission in human lungs has shown promise to reveal, by noninvasive methods, information about the structure of peripheral airways and lung tissue. The paper gives a detailed explanation of the instrumentation and testing methods developed to measure sound transmission through human lungs and thoracic structures in the 5-20
V, Goncharoff, J E, Jacobs, D W, Cugell
openaire   +2 more sources

Optimization of a transmission acoustic microscope

Journal of Applied Physics, 1978
The acoustic field focused by a spherical solid-water interface has been computed and the results have been used to optimize the geometry of a transmission acoustic microscope. An experimental study has been performed, which enables the sampling of the focused acoustic field, as may be realized by using the Fourier-transform-operation concept for an ...
E. Bridoux, B. Nongaillard, J.M. Rouvaen, C. Bruneel, G. Thomin, R. Torguet   +5 more
openaire   +1 more source

Acoustic metasurfaces for asymmetric transmission

The Journal of the Acoustical Society of America, 2015
We present a design of acoustic metasurfaces yielding highly asymmetric transmission within a certain frequency band. The design consists of a bottom layer of gradient-index metasurface and a top layer of low refractive index metasurface. When the incident waves transmit from the bottom side, the wave-front will be steered, and the total reflection ...
Chen Shen, Yun Jing
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Enhanced acoustic transmission through an aqueous acoustic metasurface

The Journal of the Acoustical Society of America, 2020
Acoustic metasurfaces are ultrathin (subwavelength thickness) structures that can demonstrate extreme acoustic properties, such as negative or near-zero values, similar to those seen in acoustic metamaterials. The negligibly small thickness of acoustic metasurfaces make them a more practical alternative to metamaterials for certain applications.
Amber M. Groopman, Theodore P. Martin, Charles A. Rohde, Caleb F. Sieck, Matthew D. Guild   +4 more
openaire   +1 more source

Efficient acoustic transmission and acoustic intensity control in topological acoustic interlayer

Physica Scripta
Abstract This paper discards the scatterers in the conventional acoustic topology and proposes a new topological acoustic interlayer structure that is different from previous studies. There is no scatterer blocking the propagation of acoustic waves in this kind of interlayer, and thus, a more efficient acoustic transmission capability ...
Xiao Liang, Zhongyuan Tang, Jiangxia Luo, Tiejun Song   +3 more
openaire   +1 more source

Enhancement of asymmetric acoustic transmission

Applied Physics Letters, 2013
We report both experimentally and theoretically that enhanced one-way acoustic transmission is realized by coupling a periodical grating with metal plates. This exotic acoustic phenomenon is attributed to the structure-induced resonant excitation of the leaky Lamb modes which arise from the coupling of the diffracted waves with the resonant surface ...
Hong-xiang Sun, Shu-yi Zhang
openaire   +1 more source

Medium for External Acoustic Transmission

1976
The transducer-skin interface artifact makes single crystal, sector-scanner and multicrystal echocardiographic assessment of anterior cardiac structures technically more difficult than posterior structure evaluation. Furthermore, because of transducer fulcrum effect (pie wedge), relatively less area of the anterior heart can be evaluated with standard ...
H. D. Allen, S. J. Goldberg, D. J. Sahn, W. L. Henry, J. M. Griffith   +4 more
openaire   +1 more source

Transmission Acoustic Microscopy Investigation

1992
The nature of acoustic contrast, i.e. the connection of the amplitude and phase of the output signal of the acoustic microscope with the local values of the acoustic parameters of the sample (density, elasticity, viscosity) is a central problem of acoustic microscopy.
Maev, R. G., Kolosov, Oleg, Levin, V. M., Lobkis, O. I.   +3 more
openaire   +1 more source

The mechanism of acoustic transmission in birds

Biology Bulletin, 2005
Neuronal activity of the medullary nuclei in response to acoustic stimuli was studied by electrophysiology. Neuronal activity was recorded from three nuclei: magnocellular, angular, and laminar. Both tonic and phasic neurons of all nuclei demonstrated a strict dependence of their discharge on temporal patterns of acoustic stimuli.
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Transmission Acoustic Vibration Testing.

1985
Abstract : Laboratory tests were conducted to determine the individual and combined effects of a high contact ratio (HCR) planetary gearset and a stainless steel housing on the acoustic (high frequency) vibration signature of the BLACK HAWK helicopter main transmission.
A. Chory, C. Yoerkie
openaire   +1 more source