Viscous damping of nanobeam resonators: humidity, thermal noise and the   paddling effect
  The nanobeam resonator is the key mechanical component in the nano-electromechanical system. In addition to its high frequency originating from its low dimension, the performance is significantly influenced by the circumstances, especially at nanoscale where a large surface area of the material is exposed. Molecular dynamics simulations and theoretical analysis are used for a quantitative prediction on the damping behavior, such as the critical damping condition and lifetime, of nanobeam resonators that directly maps the fluid-structure properties and interaction information into dynamical behaviors. We show here how the humidity defines the critical damping condition through viscous forces, marking the transition from under-damping to over-damping regime at elevated humidity. Novel phenomena such as the thermal fluctuation and paddling effects are also discussed. 
Chao Chen, Ming Ma, Jefferson Zhe Liu, Quanshui Zheng and Zhiping Xu
cond-mat.mtrl-sci cond-mat.mes-hall