| 研究実績の概要 |
This research proposes a novel ultrasonic transducer named DPLUS that outputs powerful ultrasound from a thin waveguide using double parabolic reflections, and its basic characteristics are studied.
In this year, the selection criteria of the piezoelectric material for DPLUS were firstly examined. For realizing powerful ultrasound output, the mechanical quality factor and the non-linear vibration characteristics were found as important material indexes. Under a suitable piezoelectric material, the vibration velocity in the DPLUS waveguide can reach around 10 m/s at around 30 kHz and 1.3 MHz, and the acoustic pressure between 1 to 2 MHz can reach 7.3 MPa. It was found that the saturation velocity (10 m/s) in the DPLUS waveguide comes from its material (duralumin), and therefore other materials were proposed such as metal glass and Nitinol. Study of a DPLUS with a 1-mm diameter and 1-m long Nitinol thin waveguide showed that powerful ultrasound can be transmitted through the long waveguide and the waveguide material damping was found as the most important index for improving the vibration output. By delivering the ultrasound to the animal fat, the temperature increases by 10 °C within 30 s, and the fat was melted. Therefore, successful tissue destruction was demonstrated.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
1: 当初の計画以上に進展している
理由
By studying the selection criteria of the piezoelectric material and waveguide material, high-power ultrasound output of DPLUS has been realized, and the vibration limit in the DPLUS waveguide was revealed.
In addition, therapeutic ultrasound was successfully demonstrated by a DPLUS with a 1-mm diameter and 1-m long Nitinol thin waveguide.
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| 今後の研究の推進方策 |
For a specific application of DPLUS, the optimal design of DPLUS is still unclear. For example, for therapeutic ultrasound, revealing the optimal dimensions of the DPLUS thin waveguide and the optimal working frequency are the important future research directions.
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