纳米器件中若干纳米力学基本问题的研究

To conduct systematical investigation on the novel nanodevices, oupled.electric-mechanical behaviors of CNTs and energy converting and dissipation, we have conducted function density, ab initio quantum mechanics calculations and PM3 empirical quantum mechanics calculations as well as quantum-molecular dynamics simulations. Simulations of single walled CNTs under external electric fields and applied force show that external applied electric fields can cause charge polarization and giant axial electrostriction in metallic and semi-metallic carbon nanotubes. The exceptional coupled effects among mechanical, electric and electronic.behaviors of CNTs were revealed. Self-optimized nano-bearings and nano-oscillators are found to be strongly commensuration dependent. The interlayer corrugation and resistant force in rotating, sliding and telescoping the inner tube with respect to the outer shell in multiwalled carbon nanotube systems are shown to be strongly dependent upon the morphology combination of the tubes. It is found that energy dissipation in a zigzag/armchair oscillating tube system is much smaller than that in an armchair/armchair system. The zigzag/zigzag system shows the largest.energy dissipation rate so that the oscillation driven by van der Waals interlayer interaction is dissipated within nanoseconds. Low temperature is important for smooth oscillation. Theoretical study on buckling of mono-molecular films on substrate, large deformation of CNTs, physical effects in MEMS are conducted. Some improvements on calculation efficiency of nano-mechanics.are made as well.

针对微机电系统和纳米技术中带有普遍性的关键问题，以量子力学、分子动力学、连续介质力学、热力学和能量原理为基础，采取从上到下和自下而上相结合的研究方式，多学科交叉融合，建立适于纳米器件研究的纳米力学理论框架；借助力学求解思想，建立适于纳米力学研究的求解方法。研究将推动纳米技术的发展，为纳米系统的设计和制造提供科学基础。.