碳纳米管薄膜扬声器的声场特性研究
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摘要
碳纳米管薄膜是基于热声效应产生声场的一种新型声源。文中搭建了碳纳米管薄膜扬声器系统,对其进行了声场测试和特性分析;根据已有的理论公式计算声压和频率响应,与测试结果对比,对碳纳米管薄膜声压公式进行了验证和讨论,分析了导致误差的原因。研究结果表明:碳纳米管薄膜扬声器的声压随着频率升高而增大,在低中频上升迅速,3000Hz以后趋于平缓;在远场,随着测点到薄膜的距离增大,声压逐渐减小;在近场,并非严格的平面波,计算值与测试值误差较大,已有的理论公式需要修正。
Carbon nanotube film is a new type of sound source based on thermo-acoustic effect. In this paper,a carbon nanotube thin-film speaker system is designed,the sound field test and characteristic analysis are carried out. The sound pressure and frequency response are calculated according to the theoretical formula. Compared with the test results,the sound pressure formula of the carbon nanotube film is verified and discuss the causes of the error. The results show that the sound pressure of the carbon nanotube film loudspeaker increases with the increase of the frequency,increases rapidly at the low frequency and be steady after 3000 Hz. In the far field,with the distance from the measuring point to the film increases,the sound pressure gradually reduced; in the near field,the sound is not a strict plane wave,the calculated value and the test value have a larger error,the theoretical formula needs to be amended.
Carbon nanotube film is a new type of sound source based on thermo-acoustic effect. In this paper,a carbon nanotube thin-film speaker system is designed,the sound field test and characteristic analysis are carried out. The sound pressure and frequency response are calculated according to the theoretical formula. Compared with the test results,the sound pressure formula of the carbon nanotube film is verified and discuss the causes of the error. The results show that the sound pressure of the carbon nanotube film loudspeaker increases with the increase of the frequency,increases rapidly at the low frequency and be steady after 3000 Hz. In the far field,with the distance from the measuring point to the film increases,the sound pressure gradually reduced; in the near field,the sound is not a strict plane wave,the calculated value and the test value have a larger error,the theoretical formula needs to be amended.
引文
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[3]XIAO L,LIU P,LIU L,et al.High frequency response of carbon nanotube thin film speaker in gases[J].Journal of Applied Physics,2011,110(8):084311.
[4]LIM C W,TONG L H,LI Y C.Theory of suspended carbon nanotube thinfilm as a thermal-acoustic source[J].Journal of Sound and Vibration,2013,332(21):5451-5461.
[2]RAMA V.Applied physics:nanothermal trumpets[J].Nature,2010,463:619
[3]XIAO L,LIU P,LIU L,et al.High frequency response of carbon nanotube thin film speaker in gases[J].Journal of Applied Physics,2011,110(8):084311.
[4]LIM C W,TONG L H,LI Y C.Theory of suspended carbon nanotube thinfilm as a thermal-acoustic source[J].Journal of Sound and Vibration,2013,332(21):5451-5461.