碳纳米管和二硫化钼纳米管振荡器的分子动力学研究

发布时间：2018-01-04 13:29

本文关键词：碳纳米管和二硫化钼纳米管振荡器的分子动力学研究　出处：《南昌航空大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着科技日新月异的发展,纳米科学作为本世纪的一门前沿科学,起到了举足轻重的作用。纳米材料所具有的一些独特性能,为下一代性能卓越且构造精细的仪器件的开发提供了可能。本文以当下研究热门的纳米机电系统为对象,提出了基于两种不同材料设计的纳米振荡器—传统的双壁碳纳米管(Carbon Nanotube,CNT)振荡器和新型的双壁异质CNT@MoS_2纳米管振荡器。并采用经典的分子动力学方法,研究了纳米振荡器的振荡行为特性以及相关参数对其振荡行为的影响,其主要研究内容如下:(1)此次在对扶手椅型@锯齿型的双壁碳纳米管体系的研究中,本文首次提出了一种全新的方法—螺旋上升法,即通过给扶手椅型的内管施加一个螺旋上升长度以此来改善内管的振荡行为。运用分子动力学模拟的方法,我们分析了不同大小的螺旋上升长度对内管振荡稳定性、振荡幅度和振荡频率的影响。研究发现内管的振荡行为对螺旋上升长度很敏感。扶手椅型的内管在逐渐增加螺旋上升长度后,其轴向的自激发振荡行为有所改善,且当扶手椅型的内管所具有的螺旋上升长度大小为1nm时,在800ps后,它能保持稳定的振荡且其振荡的平衡位置与初始时刻的位置也能相互匹配。通过此次模拟,我们发现可以给扶手椅型的内管施加一个合适的螺旋上升长度来设计一种稳定和低耗散的旋转自激发双壁碳纳米管振荡器。(2)CNT@MoS_2双壁纳米管振荡器在此次研究中首次通过了分子动力学的方法对其振荡行为进行了考察。模拟结果显示,本次研究的异质形态CNT@MoS_2双壁纳米管振荡器,其内管能在间距值为0.289nm~0.681nm的范围内稳定而持续的振荡且其振荡频率能达到吉兆赫兹以上,与传统的碳纳米管振荡器相比,异质形态的CNT@MoS_2纳米管振荡器具有很宽的间距优势。模拟结果还显示CNT@MoS_2双壁纳米管的内、外管具有不同的管状结构特征时,其更适合充当低损耗振荡的纳米振荡器。(3)通过分子动力学方法,首次研究了旋转型CNT@MoS_2双壁纳米管体系其内管轴向的自激发振荡行为。模拟结果显示,CNT@MoS_2双壁纳米管体系其内管能在5GHz~500GHz的旋转频率下一直保持持续而稳定的轴向振荡,且其振荡频率能达到吉兆赫兹,而对于以往传统的旋转型双壁碳纳米管体系其内管的自激发振荡行为要经过很长一段时间的激励才能保持稳定的振荡。模拟中还研究了温度对旋转型CNT@MoS_2双壁纳米管振荡行为的影响。研究发现当体系的温度低于300K时,内管沿轴向的振荡行为在整个模拟过程中表现的很稳定且内管的振荡幅度和振荡频率随着温度的升高都有所增加;而当体系温度达到300K时,内管的振荡行为却很不稳定。
[Abstract]:With the rapid development of science and technology, nanoscience, as a frontier science in this century, plays an important role. Nanomaterials have some unique properties. For the next generation of excellent performance and fine structure of the development of instruments. This paper focuses on the current research on nano-electromechanical systems as the object. A novel nano-oscillator based on two different materials, the traditional two-walled carbon nanotube Nanotube, is proposed. CNT) oscillator and a new type of double-walled heterostructure CNT@MoS_2 nanotube oscillator are used in this paper. The classical molecular dynamics method is also used. The characteristics of oscillatory behavior and the effect of related parameters on the oscillatory behavior of nano-oscillator are studied. The main contents of this study are as follows: 1) in this study, the armchair type @ sawtooth double-walled carbon nanotube system is studied. In this paper, a new method, the spiral rise method, is proposed for the first time, in order to improve the oscillatory behavior of the inner tube by adding a spiral rise length to the inner tube of the armchair, and the method of molecular dynamics simulation is used. The stability of the internal tube oscillating with different spiral riser lengths is analyzed. It is found that the oscillation behavior of the inner tube is very sensitive to the spiral rise length. The armchair type inner tube increases the spiral rise length gradually. The axial self-excited oscillation behavior is improved, and when the spiral rise length of the armchair type inner tube is 1 nm, after 800 PS. It can maintain stable oscillation and the equilibrium position of its oscillation can match the position of the initial moment. We have found that an appropriate spiral rise length can be applied to the armchair type inner tube to design a stable and low dissipative rotating self-excited double-walled carbon nanotube oscillator. In this study, the oscillation behavior of CNT@MoS_2 double-walled nanotube oscillator was investigated by molecular dynamics for the first time. The heterostructure of CNT@MoS_2 double-walled nanotube oscillator is studied in this paper. The inner tube can oscillate steadily and continuously in the range of 0.289 nm and 0.681nm, and its oscillation frequency can reach more than gigahertz, which is compared with the traditional carbon nanotube oscillator. The heterogenous CNT@MoS_2 nanotube oscillator has the advantage of wide spacing. The simulation results also show that the CNT@MoS_2 double-walled nanotubes have different tubular structure characteristics. It is more suitable to act as a low-loss oscillating nano-oscillator. The self-excited oscillation behavior of the inner tube in a rotating CNT@MoS_2 double-walled nanotube system is investigated for the first time. The inner tube of CNT@MoS_2 double-walled nanotube system can maintain a constant and stable axial oscillation at the rotation frequency of 5GHz ~ 500GHz, and its oscillation frequency can reach GHz. However, the self-excited oscillation behavior of the inner tube of the traditional rotating double-walled carbon nanotube system can be kept stable only after a long period of excitation. In the simulation, the effect of temperature on the rotation type CNT@M is also studied. The effect of the oscillatory behavior of oS_2 double-walled nanotubes. It is found that the temperature of the system is lower than 300K. The oscillation behavior of the inner tube along the axial direction is very stable in the whole simulation process and the oscillation amplitude and frequency of the inner tube increase with the increase of temperature. However, when the temperature of the system reaches 300 K, the oscillation behavior of the inner tube is unstable.
【学位授予单位】：南昌航空大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN752;TB383.1

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