Miniaturized sound generators are attractive to realize intriguing functions.Thermoacoustic device’s application is seriously limited due to the frequency-doubling phenomenon.To address this issue,photoacoustic sound...Miniaturized sound generators are attractive to realize intriguing functions.Thermoacoustic device’s application is seriously limited due to the frequency-doubling phenomenon.To address this issue,photoacoustic sound generator is considered as a promising alternative.Here,based on vertical single-wall carbon nanotubes(CNTs)array,we introduce a photoacoustic sound generator with internal nano-Helmholtz cavity.Different from traditional device that generates sound by periodically heating up the open space air around material,this sound generator produces an audio signal by forming a forced vibration of the air inside the CNTs.Interestingly,anomalous photoacoustic behavior is observed that the sound pressure level(SPL)curve has a resonance peak,the corresponding frequency of which is inversely proportional to the CNTs array’s height.Furthermore,the energy conversion efficiency of this photoacoustic device is 1.64 times as large as that of a graphene sponge-based photoacoustic device.Most importantly,this device can be employed for music playing,bringing a new clew for the development of musical instruments in the future.展开更多
Fe_(3)O_(4)/CNTs纳米复合材料用水热法在乙醇和丙二醇的混合溶液中合成,尺寸为5~15 nm的四氧化三铁纳米颗粒均匀附着在碳纳米管表面。作为锂电池负极材料,合成的Fe_(3)O_(4)/CNTs纳米复合材料展现出了优异的长循环特性和倍率循环特性...Fe_(3)O_(4)/CNTs纳米复合材料用水热法在乙醇和丙二醇的混合溶液中合成,尺寸为5~15 nm的四氧化三铁纳米颗粒均匀附着在碳纳米管表面。作为锂电池负极材料,合成的Fe_(3)O_(4)/CNTs纳米复合材料展现出了优异的长循环特性和倍率循环特性。在电流密度100 mA g^(-1)的条件下,在300次循环充放电后容量仍然能够保持在605 mAh g^(-1)。酸处理碳纳米管的加入为四氧化三铁提供了大量的生长点,显著减小了四氧化三铁颗粒的尺寸,阻止了充放电过程中颗粒的团聚,构建了独特的三维导电网,使复合材料展现出了优异的电化学性能。展开更多
文摘Miniaturized sound generators are attractive to realize intriguing functions.Thermoacoustic device’s application is seriously limited due to the frequency-doubling phenomenon.To address this issue,photoacoustic sound generator is considered as a promising alternative.Here,based on vertical single-wall carbon nanotubes(CNTs)array,we introduce a photoacoustic sound generator with internal nano-Helmholtz cavity.Different from traditional device that generates sound by periodically heating up the open space air around material,this sound generator produces an audio signal by forming a forced vibration of the air inside the CNTs.Interestingly,anomalous photoacoustic behavior is observed that the sound pressure level(SPL)curve has a resonance peak,the corresponding frequency of which is inversely proportional to the CNTs array’s height.Furthermore,the energy conversion efficiency of this photoacoustic device is 1.64 times as large as that of a graphene sponge-based photoacoustic device.Most importantly,this device can be employed for music playing,bringing a new clew for the development of musical instruments in the future.
文摘Fe_(3)O_(4)/CNTs纳米复合材料用水热法在乙醇和丙二醇的混合溶液中合成,尺寸为5~15 nm的四氧化三铁纳米颗粒均匀附着在碳纳米管表面。作为锂电池负极材料,合成的Fe_(3)O_(4)/CNTs纳米复合材料展现出了优异的长循环特性和倍率循环特性。在电流密度100 mA g^(-1)的条件下,在300次循环充放电后容量仍然能够保持在605 mAh g^(-1)。酸处理碳纳米管的加入为四氧化三铁提供了大量的生长点,显著减小了四氧化三铁颗粒的尺寸,阻止了充放电过程中颗粒的团聚,构建了独特的三维导电网,使复合材料展现出了优异的电化学性能。
