| Presentation | 2011-01-20 Second Harmonic Component in Focused Gaussian Beam Transmitting through a Layer with Nonuniformly Distributed Sound-Speed Shigemi SAITO, |
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| Abstract(in Japanese) | (See Japanese page) |
| Abstract(in English) | A method to measure automatically and display two-dimensionally the nonlinearity parameter B/A in the biological sample inserted in the focal region of the focused Gaussian beam in water has previously been presented. Although the nonuniformity of B/A in the sample was then observed, the measured B/A is not fully reliable because the measuring principle assumes uniform samples. In this article, the fundamental and second harmonic components in the focused sound transmitting through the layer of the medium with a monotonous sound-speed variance in one direction are analyzed and the influence on the B/A measurement is investigated. The Khokhlov-Zabolotskaya equation including the small perturbation due to a slightly nonuniform sound-speed is solved with the successive approximation. As a result, it is clarified that the sound pressure induced by the perturbation does not affect the received signal in principle in the case of the variance normal to the acoustic axis. On the other hand, in the case of axial variance, it is shown that the amplitude of the second harmonic slightly differs from that defined by the average sound-speed. Then the measurement error of the nonlinearity coefficient β is generated by the rate less than 1.8 times the axial change-rate in sound-speed within the layer. |
| Keyword(in Japanese) | (See Japanese page) |
| Keyword(in English) | Focused Sound / Nonlinear Propagation / Second Harmonic / Nonuniform Medium / Successive Approximation |
| Paper # | US2010-95 |
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| Conference Information | |
| Committee | US |
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| Conference Date | 2011/1/13(1days) |
| Place (in Japanese) | (See Japanese page) |
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| Topics (in Japanese) | (See Japanese page) |
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| Paper Information | |
| Registration To | Ultrasonics (US) |
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| Language | JPN |
| Title (in Japanese) | (See Japanese page) |
| Sub Title (in Japanese) | (See Japanese page) |
| Title (in English) | Second Harmonic Component in Focused Gaussian Beam Transmitting through a Layer with Nonuniformly Distributed Sound-Speed |
| Sub Title (in English) | |
| Keyword(1) | Focused Sound |
| Keyword(2) | Nonlinear Propagation |
| Keyword(3) | Second Harmonic |
| Keyword(4) | Nonuniform Medium |
| Keyword(5) | Successive Approximation |
| 1st Author's Name | Shigemi SAITO |
| 1st Author's Affiliation | School of Marine Science and Technology, Tokai University() |
| Date | 2011-01-20 |
| Paper # | US2010-95 |
| Volume (vol) | vol.110 |
| Number (no) | 366 |
| Page | pp.pp.- |
| #Pages | 6 |
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