The sound-transmission, beam-formation, and sound-reception processes of a short-finned pilot whale (Globicephala macrorhynchus) were investigated using computed tomography (CT) scanning and numerical simulation. The results showed that sound propagations in the forehead were modulated by the upper jaw, air components, and soft tissues, which attributed to the beam formation in the external acoustic field. These structures owned different acoustic impedance and formed a multiphasic sound transmission system that can modulate sounds into a beam. The reception pathways composed of the solid mandible and acoustic fats in the lower head conducted sounds into the tympano-periotic complex. In the simulations, sounds were emitted in the forehead transmission system and propagated into water to interrogate a steel cylinder. The resulting echoes can be interpreted from multiple perspectives, including amplitude, waveform, and spectrum, to obtain the acoustic cues of the steel cylinder. By taking the short-finned pilot whale as an example, this study provides meaningful information to further deepen our understanding of biosonar system operations, and may expand sound-reception theory in odontocetes.

中文翻译：

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基于数值建模的短鳍领航鲸 (Globicephala macrorhynchus) 声音传输和接收研究

短鳍领航鲸 ( Globicephala macrorhynchus)的声音传输、波束形成和声音接收过程) 使用计算机断层扫描 (CT) 扫描和数值模拟进行研究。结果表明，前额中的声音传播受到上颌、空气成分和软组织的调制，这归因于外部声场中的波束形成。这些结构具有不同的声阻抗，形成了多相声传输系统，可以将声音调制成光束。由下头部的固体下颌骨和声学脂肪组成的接收通路将声音传导到鼓膜 - 鼓膜复合体中。在模拟中，声音在前额传输系统中发出并传播到水中以询问钢瓶。由此产生的回波可以从多个角度解释，包括幅度、波形和频谱，以获得钢瓶的声学线索。以短鳍领航鲸为例，本研究为进一步加深我们对生物声纳系统操作的理解提供了有意义的信息，并可能扩展齿鲸的声音接收理论。