Nanomechanical resonators often exhibit nonlinear dynamic behaviors due to their small sizes. In this study, we show that the geometric nonlinearity of high-Q Si3N4 nanomechanical string resonators can be substantially tuned by support design. Through careful engineering of support geometries, we control both stress and geometric nonlinearities, tuning nonlinear dynamics from hardening to softening solely by mechanical design. Our work offers new insights into nullifying or enhancing nonlinearity in a purely mechanical manner which is of interest for resonant sensors.

In this paper, we design, develop, and assess the performance of MEMS gas sensors coated with a metal organic framework, namely Zeolitic imidazolate framework (ZIF-8). We demonstrate the potential use of nonlinear dynamic features of electrostatic MEMS resonators, captured using the motion-induced current method, to detect CO2 and determine its concentration

A new method has been developed to gradually reconstruct the topography of surfaces. The technique involves measuring the changes in the dynamic vibration of a Nanofiber, which is moved parallel to the measured surface and gradually inserted deeper without physical contact. The Nanofiber vibrates and measures the wall of a deep groove, and the intermolecular forces between the vibrating fiber and the measured surface, such as Van der Waals (VdW) interaction forces, allow for measurable changes in the dynamics to be observed. This method can reconstruct the topography of inaccessible surfaces beyond current AFM capabilities. The estimate of topography distribution is refined based on a simplified, decoupled model, and it can be demonstrated that the simplified model converges to the fully coupled one, thus reconstructing the true topography. The paper also includes simulated examples of magnetic and VdW forces, along with a large-scale experiment with magnetic forces that simulate intermolecular forces.