1,720,965 research outputs found
Optimum Structural Design of Micromechanical Crab-Leg Flexures with Microfabrication Constraints
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VISCOUS DAMPING MODEL FOR LATERALLY OSCILLATING MICROSTRUCTURES
No full textViscous energy loss in oscillating fluid-film dampers that provide frictional shear for laterally-driven planar microstructures is investigated. It is found that Stokes-type fluid motion models viscous damping more accurately than Couette-type flow field. This paper characterizes the damping property of a fluid layer in terms of viscous energy dissipation, then derives analytic damping formulae for practical Q estimation. Theoretical Q-factors are compared to the experimental values, measured from surface-micromachined polysilicon resonators. Data reported by previous investigators are also analyzed and compared. The experimental results indicate that the Stokes-type damping model presents a more general damping treatment with better Q estimation, although discrepancies of 10 to 20% still remain between the estimated and measured Q. [59
Nanomechanical protein concentration detector using a nanogap squeezing actuator with compensated displacement monitoring electrodes
No full textWe present a new class of the protein concentration detector based on the mechanical stiffness measurement of protein-receptor layers in a squeezed nanogap. Compared to the previous protein size detector, the present device reduces the distortion and uncertainty in the displacement measurement by adding an actuated nanogap and reference electrodes. Compared to the conventional protein detectors based on electrochemical, optical, optomechanical, and mechanical principles, the present device also offers simple, inexpensive, and high-precision protein detection. We design and fabricate the protein concentration detector using an electrothermal actuator and two nanogaps with reference electrodes. In an experimental study, we verify that the present protein detector measures the size of the proteins streptavidin and m-antibiotin as 12.1 +/- 2.3 and 13.2 +/- 3.3 nm at the measurement uncertainty of +/- 1.9 nm, respectively, while showing the concentration detection sensitivity of 2.88 N/m/nM in the m-antibiotin concentration range of 5-10 nM
A Nanomechanical Protein Concentration Detector Using a Nano-Gap Squeezing Actuator with Compensated Displacement Monitoring Electrodes
No full textSLIDE FILM DAMPING IN LATERALLY DRIVEN MICROSTRUCTURES
No full textSlide film damping occurs when two parallel plates are in relative tangential motion. Viscous energy dissipation in the fluid between the two plates becomes a representative damping mechanism in laterally driven microdevices. In this paper, we investigate the slide film damping both theoretically and experimentally. A new physical model has been proposed for the characterization of slide film damping. Dynamic characteristics of a fluid film have been described in terms of velocity profiles, damping mechanisms, and levels of viscous energy dissipation. Simplified analytical damping formulae have been developed for practical Q estimation. The theoretical Q compares well with the experimental Q. Data reported by previous investigators are also analyzed and compared with the Q value estimated in the present study. It is concluded that our theoretical model offers simple and reasonably good quantitative prediction of Q. Possible sources of error in the theoretical Q prediction are discussed. The effects of fluid-film thickness and microstructure geometry on Q are investigated, so that the results can be used in the damping design for laterally driven microtransducers
Nanomechanical Protein Presence and Concentration Detectors Based on the Mechanical Stiffness of Proteins in Squeezed Nano-Gaps
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