Nano and micro electro-mechanical systems (NEMS and MEMS) have been attracting a large amount of attention recently as they have extensive current/potential applications. However, due to their scale, molecular interaction and size effects are considerably high which needs to be considered in the theoretical modelling of their electro-mechanical behaviour. Both nano- and micro-scale electrically actuated structures are discussed when subjected to constant and time-varying voltages, and different theories and models, introduced in the past few years for modelling such small structures, are discussed. It is highlighted that considering the intermolecular forces and size-dependence effects can change both the static and dynamic behaviours of such systems significantly. This review presents the current stage of the research on electrically actuated NEMS/MEMS by analysing the latest models and studies in this field in the framework of electro-mechanical coupling and small-size effects.

纳米和微机电系统（NEMS和MEMS）由于具有广泛的电流/潜在应用而最近引起了广泛的关注。然而，由于它们的规模，分子相互作用和尺寸效应非常高，这在它们的机电行为的理论模型中需要考虑。讨论了在恒定电压和时变电压下的纳米级和微米级电动结构，并讨论了过去几年引入的用于建模此类小型结构的不同理论和模型。需要强调的是，考虑分子间作用力和尺寸依赖性效应可以显着改变此类系统的静态和动态行为。