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首先阐述了碳纳米管声学桥的这一新概念,即通过共振超声谱方法测量置放在两个微型压电换能器之间的碳纳米管的多个固有频率,确定其物理特性。作为碳纳米管声学桥的理论基础,文中应用解析方法和有限元数值方法分析了碳纳米管声学桥的声波传播特性,重点研究了碳纳米管声学桥结构尺寸与振动模式的品质因数之间的关系。在此基础上,探讨了声学桥的三个潜在应用场合:作为研究碳纳米管材料特性的有力工具;碳纳米管声学桥对微小质量变化具有10-220g/Hz的灵敏度,可作为高精度质量敏感元件;碳纳米管声学桥在周围环境真空压力改变时,谐振频率会变化,通过测量频移来确定真空压力,故碳纳米管声学桥可作为超高真空传感器。 ; In this paper,we first present a new method/concept for the investigation of physical properties of carbon nanotubes,which is called carbon nanotube acoustic bridge.It is using resonant ultrasound spectroscopy(RUS) to obtain the eigenfrequencies of the carbon nanotube that is slightly clamped between two micro ultrasonic transducers,or it refers to that the carbon nanotube clamped between two ultrasonic transducers only propagates those acoustic waves whose frequencies are identical to its eigenfrequencies.Then we study the theoretical basis of carbon nanotube acoustic bridge by using the analytical method and finite element method in ANSYS to acquire the acoustic wave modes in carbon nanotube acoustic bridge.Especially,we derive the relationship between the structural parameters of carbon nanotube and the quality factor of its vibration modes.Based on these,three potential applications of carbon nanotube acoustic bridge are established: it is used as a powerful tool to study the material properties of various kinds of carbon nanotubes;it is proved to own a sensitivity of 10-220 g/Hz to an extremely small change of mass,which enables it used as a mass-changing detector with high sensitivity;with the derived relationship between the shift of its resonance frequencies and the pressure where the carbon nanotube acoustic bridge is,it can used as a vacuum sensor for ultrahigh vacuum. ; 厦门大学引进人才科研启动基金资助 |
