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trolling-mode-atomic-force-microscopy--afm
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Simulation of Imaging in Trolling Mode Atomic Force Microscopy by Molecular Dynamics Method
, M.Sc. Thesis Sharif University of Technology ; Nejat Pishkenari, Hossein (Supervisor)
Abstract
Atomic force microscopy (AFM), as an indispensable tool for nanoscale characterization, has major drawback for operation in a liquid environment arising from the large hydrodynamic drag on the vibrating cantilever. The newly introduced “Trolling Mode” (TR-Mode) AFM resolves this complication utilizing a specialized nanoneedle cantilever that keeps the cantilever outside of the liquid. Herein, a mechanical model with a lumped mass was developed to capture the dynamics of such cantilever with a nanoneedle tip. This new developed model was applied to investigate the effects of the needle – liquid interface on the performance of the AFM, including the imaging capability in liquid. Also...
Dynamic Modeling and Control of Atomic Force Microscope in Trolling Mode
, Ph.D. Dissertation Sharif University of Technology ; Vosoughi, Gholamreza (Supervisor) ; Nejat Pishkenari, Hossein (Supervisor)
Abstract
Trolling mode atomic force microscope (TR-AFM) significantly reduces the hydrodynamic drag generated during operation in liquid environments. This is achieved by utilizing a long nanoneedle and keeping the cantilever out of liquid. In this research, a continuous mathematical model is developed to study TR-AFM dynamics near a sample submerged in the liquid. Effects of cantilever torsion, nanoneedle flexibility, and liquid-nanoneedle interactions are considered in the model. The finite element model of the TR-AFM resonator considering the effects of fluid and nanoneedle flexibility is presented in this research, for the first time. The model is verified by ABAQUS software. The effect of...
Modeling of Force Interactions between Tip of Atomic Force Microscopy in Trolling Mode and Environment
, M.Sc. Thesis Sharif University of Technology ; Nejat Pishkenari, Hossein (Supervisor)
Abstract
Submerging of the Micro-beam of the AFM is indispensible in case of imaging bio-samples. (Bio-samples are unstable in non-aquos environment.), so hydrodynamical interaction of liquid and beam (viscous and meniscus forces) will result into quality factor decrease. This will cause image resolution decrement as well as damage to the sample because of large tip-sample forces during imaging of the bio-samples. The proposed method “Trolling mode AFM” keeps the micro-beam of the AFM out of the liquid, by adding a nano-needle to the end of the AFM tip. This would lead to resolve the aforementioned problems. Modeling of a part of the operation of this mechanism was done in this thesis, in order to...