The space charges appear to exist in the region from 14.9 m to 16 m high above the ground and have maximum charge density of 400 nC m-3 as shown in Fig. 8. The height of the charge region is consistent with phase 3 the height of the grounded tower. The measured charge density is about 10 times as selleck chemical Axitinib large as the value measured above a truck farm under the winter thundercloud [Tatsuoka et al., 1991]. The electric field
Inherent instability such as in pull-in phenomenon and stiction exists in both microelectromechanical (MEM) and nanoelectromechanical (NEM) actuators. Inhibitors,Modulators,Libraries Such instability is due to some kind of surface force, i.e. electrostatic, van der Waals (vdW), Casimir and capillary forces. Although vdW and Casimir forces can be neglected when designing a MEM actuator, they play important roles at nanoscales [8-13].
A typical MEM (NEM) parallel-plate (or torsional) actuator is made up of two conducting electrodes, one is typically fixed and the other, Inhibitors,Modulators,Libraries which is controlled by an equivalent mechanical Inhibitors,Modulators,Libraries spring, is movable (or rotary) [1-4]. Inhibitors,Modulators,Libraries The corresponding system can be simplified to one degree of freedom (1DOF). The 1DOF is the displacement,u, of the upper movable beam for the parallel-plate model, and is the torsional angle, ��, for the torsional model. At a certain voltage, the movable electrode becomes unstable and collapses (or pulls-in) to the ground plane. The voltage and displacement (or torsional angle) of the actuators under this state are said to be the pull-in voltage and pull-in displacement (or the pull-in angle) for the Inhibitors,Modulators,Libraries parallel-plate (or torsional) actuators, respectively.
They are briefly described as the pull-in parameters.Using Inhibitors,Modulators,Libraries a one-dimensional (1D) model, the pull-in parameters have been analytically obtained by many researchers when electrostatic [5-7], vdW and Casimir forces [8-16] are considered. The bifurcation Inhibitors,Modulators,Libraries analysis for an electrostatic micro-(nano-) actuator has been addressed in [9-17] with the Inhibitors,Modulators,Libraries consideration of electrostatic, vdW, and Casimir forces for the parallel-plate and torsional actuators. In [9, 11, 12], the influences of vdW or Casimir force (torque) on the electrostatic parallel-plate (torsional) actuators was studied. There are two bifurcation points, of which one is a Hopf bifurcation point, and the other is an unstable saddle point.
Drug_discovery The phase portraits are also drawn, in which periodic orbits are around the Hopf bifurcation point, but the periodic orbit will break into a Carfilzomib homoclinic selleck chemicals llc orbit when meeting the unstable saddle point.In this paper, the influence of damping on the dynamical Olaparib order behavior of the electrostatic parallel-plate and torsional actuators with the vdW or Casimir force (torque) is presented, and the results are compared with those in Refs. [9, 11, 12]. The damping considered in this paper can be a kind of gas (squeeze film) friction which is assumed, without loss of generality, to be linearly proportional to the velocity.2.