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Localization of ultrasonic waves in ...

Hu, Hefei.

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Localization of ultrasonic waves in an open three-dimensional system.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Localization of ultrasonic waves in an open three-dimensional system./
Author:	Hu, Hefei.
Description:	174 p.
Notes:	Source: Masters Abstracts International, Volume: 45-03, page: 1514.
Contained By:	Masters Abstracts International45-03.
Subject:	Physics, Acoustics. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=MR22516
ISBN:	9780494225165

Localization of ultrasonic waves in an open three-dimensional system.
Hu, Hefei.

Localization of ultrasonic waves in an open three-dimensional system. - 174 p.

Source: Masters Abstracts International, Volume: 45-03, page: 1514.

Thesis (M.Sc.)--University of Manitoba (Canada), 2007.

The transport of ultrasound through a strongly scattering medium, with either a random or ordered mesostructure, was studied in the intermediate frequency regime, where the wavelength in the sample is comparable to the size of the scatterers. The samples were made by braising aluminum beads to form a solid network, held together by weak bonds between the beads. In the random samples, wave transport was found to be diffusive in the lower part of the intermediate frequency regime (&sim;0.25 MHz). At higher frequencies (&sim;2 MHz), the diffusion approximation was found to break down, and the localization of ultrasound was observed. This demonstration of ultrasonic wave localization, believed to be the first experimental realization of this effect in three dimensions, was based on two approaches: the observation of time dependence in the diffusion coefficient, and evidence for non-Rayleigh statistics and anomalously large variance of the normalized transmitted intensity. Band gaps were observed in both the random and crystalline aluminum bead samples, and in the crystals, the group velocity was found to be negative in the lowest frequency gap.

ISBN: 9780494225165Subjects--Topical Terms:

1019086
Physics, Acoustics.

Localization of ultrasonic waves in an open three-dimensional system.
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035 $a (UMI)AAIMR22516
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100 1 $a Hu, Hefei. $3 1923197
245 1 0 $a Localization of ultrasonic waves in an open three-dimensional system.
300 $a 174 p.
500 $a Source: Masters Abstracts International, Volume: 45-03, page: 1514.
502 $a Thesis (M.Sc.)--University of Manitoba (Canada), 2007.
520 $a The transport of ultrasound through a strongly scattering medium, with either a random or ordered mesostructure, was studied in the intermediate frequency regime, where the wavelength in the sample is comparable to the size of the scatterers. The samples were made by braising aluminum beads to form a solid network, held together by weak bonds between the beads. In the random samples, wave transport was found to be diffusive in the lower part of the intermediate frequency regime (&sim;0.25 MHz). At higher frequencies (&sim;2 MHz), the diffusion approximation was found to break down, and the localization of ultrasound was observed. This demonstration of ultrasonic wave localization, believed to be the first experimental realization of this effect in three dimensions, was based on two approaches: the observation of time dependence in the diffusion coefficient, and evidence for non-Rayleigh statistics and anomalously large variance of the normalized transmitted intensity. Band gaps were observed in both the random and crystalline aluminum bead samples, and in the crystals, the group velocity was found to be negative in the lowest frequency gap.
590 $a School code: 0303.
650 4 $a Physics, Acoustics. $3 1019086
690 $a 0986
710 2 0 $a University of Manitoba (Canada). $3 1018707
773 0 $t Masters Abstracts International $g 45-03.
790 $a 0303
791 $a M.Sc.
792 $a 2007
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=MR22516