| 摘要 |
An improved ultrasonic transducer designed for rugged outdoor applications uses a thin-walled cylindrical tube of polarized ceramic operating in the fundamental circumferential resonant frequency mode. The major portion of the external surface area of the vibrating cylinder is covered by a sound insulating barrier, thereby preventing sound radiation from the covered non-radiating surface area portion of the cylinder. Specific unique relationships between the diameter, length and wall thickness of the ceramic tube, which are necessary to achieve the objects of the invention, are described.
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