计及Casimir效应时旋转式NEMS致动器的动态稳定性研究

分析了Casimir力对旋转式纳电子机械(NEMS)致动器动态稳定性的影响.计及Casimir效应时,旋转式致动器失稳时的临界倾角和临界电压和结构的几何尺寸有关.外加电压为零时,导出了旋转式致动器在Casimir力作用下发生吸合的临界特征几何尺寸.给出了旋转式致动器的无量纲化运动控制方程,并对它作了定性分析.定性分析表明:该运动方程相应的自治系统在相平面上的平衡点包括中心点、稳定的焦点和不稳定的鞍点;相图呈现周期轨道、同宿轨道以及异宿轨道.另外系统还存在分叉现象.

Influence of van der Waals and Casimir Forces on Electrostatic Torsional Actuators

The influence of van der Waals (vdW) and Casimir forces on the stability of the electrostatic torsional nanoelectromechanical systems (NEMS) actuators is analyzed in the paper. With the consideration of vdW and Casimir effects, the dependence of the critical tilting angle and pull-in voltage on the sizes of structure is investigated. And the influence of vdW torque is compared with that of Casimir torque. The modified coefficients of vdW and Casimir torques on the pull-in voltage are, respectively, calculated. When the gap is sufficiently small, pull-in can still take place with arbitrary small angle perturbation because of the action of vdW and Casimir torques even if there is not electrostatic torque. And the critical pull-in gaps for two cases are, respectively, derived.

Surface Stability of Epitaxial Elastic Films by Casimir Force

We investigate the morphological stability of epitaxial thin elastic films on a substrate by the Casimir force between the film surface and a flat plate. Critical undulation wavelengths are derived for two different limit conditions. Consideration of the Casimir force in both limit cases decreases the critical wavelength of the surface perturbation.

Casimir Effect on the Pull-in Parameters of Nanometer Switches

Casimir effect on the critical pull-in gap and pull-in voltage of nanoelectromechanical switches is studied. An approximate analytical expression of the critical pull-in gap with Casimir force is presented by the perturbation theory. The corresponding pull-in parameters are computed numerically, from which one can notice the nonlinear effect of Casimir force on the pull-in parameters. The detachment length has been presented, which increases with increasing thickness of the beam.