多壁纳米碳管振子及其能量耗散的分子动力学模拟

Simulation of the Energy Dissipation Mechanisms in Multiwall Carbon Nanotube Oscillators with Molecular Dynamics

运用分子动力学模拟的方法,模拟了不同温度下,不同管型的多壁纳米碳管振子;讨论了温度变化、壁面原子间的匹配程度对振动特性及振动过程中能量耗散的影响,根据能量的消耗来计算管壁间的摩擦力的大小.模拟结果表明,多壁纳米碳管振子在作减幅振动过程中不断有能量的消耗,振动频率可以超过80吉赫(GHz),振动时的恢复力与内外碳管重叠面积无关,通过统计消耗能量所计算的摩擦力大小在10-5nN/atom量级;摩擦力的大小随温度升高有增大的趋势,但与管壁间原子匹配程度的相关性不大.

Different type multiwall carbon nanotube oscillators were simulated at different temperature using molecular dynamic method. The influence of system temperature and atom commensurate situation on vibration characteristic and energy dissipation in this process were analyzed. The friction force between walls was calculated through evaluating the dissipated energy. The amplitude of the oscillation decreases with the time elapse and the vibration frequency can even exceed 80GHz. The restore force is independent of the overlap area between the inner and the out tubes. The friction force is calculated to 10^-5 nN/atom magnitude, and it increases with the system temperature, but it does not depend on to the atom commensurate level between the inner and the outer tubes.