No abstract

Previous works on suspended carbon nanotube and nanowire resonators assume a priori that they oscillate in a single plane. We explore the nonlinear dynamics of such resonators and demonstrate that they can suddenly transition from a planar motion to a whirling, "jump rope" like motion. We identify nondimensional gate voltage, resonator geometry, quality factor, and flexural and axial elastic stiffnesses for which such motions can arise. The deliberate use of nonlinear and nonplanar motions opens up a variety of new modalities for this class of nanoelectromechanical systems that are not accessible in the linear operating regime.

No abstract

Pediatric cognitive pharmacy services to patients at the UNC pediatric nephrology clinic were feasible, which improved the quality of services and promoted better outcomes for these complex patients.

When a microcantilever with a nanoscale tip is scanned laterally over a surface to measure the nanoscale frictional forces, the onset of stick-slip tip motions is an extremely important phenomenon that signals the onset of lateral friction forces. In this article, we investigate theoretically the influence of tip and microcantilever compliance on this phenomenon. We show that static considerations alone cannot predict uniquely the onset of single or multiple atom slip events. Instead, the nonlinear dynamics of the tip during a slip event need to be carefully investigated to determine if the tip evolves to a single or multiple atom stick-slip motions. The results suggest that the relative compliances of the tip and microcantilever can be engineered to induce single or multiple atom stick-slip events and thus control lateral friction forces at the nanoscale.