An Analytical Capacitance Model of Temperature-Sensitive, Large-Displacement Multimorph Cantilevers: Numerical and Experimental Validation

Scott, Sean; Kim, Jeong-Il; Sadeghi, Farshid; Peroulis, Dimitrios

doi:10.1109/jmems.2011.2171323

Cited by 11 publications

(11 citation statements)

References 31 publications

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“…8,38,40 Fig . The value of t 1 is 5 mm for the dry rGO papers and 150 mm for the hydrogel papers while their t 2 values are $85 mm and $70 mm respectively.…”

Section: Resultsmentioning

confidence: 99%

Tuning the oxygen functional groups in reduced graphene oxide papers to enhance the electromechanical actuation

et al. 2015

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The superior mechanical flexibility, mechanical strength, electrical conductivity, high specific surface area, and a special two-dimensional crystalline structure make graphene a very promising building block material for flexible electromechanical actuators. However, graphene papers have exhibited limited electromechanical actuation strain in aqueous electrolyte solution. In this paper, we show an easy approach to significantly improve the electromechanical actuation of reduced graphene oxide (rGO) papers via fine tuning the oxygen functional groups in rGO sheets, which was achieved by careful control of quantity of the reduction agent used in the chemical reduction process of graphene oxide.The actuation strains are enhanced up to 0.2% at an applied voltage of À1 V, which is more than a 2 fold increase compared to the regular pristine rGO paper. Further theoretical and experimental analyses reveal that the change of the capacitance and the stiffness of the rGO papers are two key factors responsible for the observed improvement.

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“…8,38,40 Fig . The value of t 1 is 5 mm for the dry rGO papers and 150 mm for the hydrogel papers while their t 2 values are $85 mm and $70 mm respectively.…”

Section: Resultsmentioning

confidence: 99%

Tuning the oxygen functional groups in reduced graphene oxide papers to enhance the electromechanical actuation

et al. 2015

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“…In 1925, Timoshenko [216] presented the analysis for such a structure with a constant temperature distribution. The analysis of multimorph beams experiencing strain from thermal expansion was presented in [217] and [218]. is the bending moment in the beam (internal bending moment).…”

Section: B13 Analytical Methodsmentioning

confidence: 99%

Single‐Chip Scanning Probe Microscopes

Sarkar

Mansour²

2015

Micro‐ and Nanomanipulation Tools

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Scanning probe microscopes (SPMs) are the highest resolution imaging instruments available today and are among the most important tools in nanoscience. Conventional SPMs suffer from several drawbacks owing to their large and bulky construction and to the use of piezoelectric materials. Large scanners have low resonant frequencies that limit their achievable imaging bandwidth and render them susceptible to disturbance from ambient vibrations. Array approaches have been used to alleviate the bandwidth bottleneck; however as arrays are scaled upwards, the scanning speed must decline to accommodate larger payloads. In addition, the long mechanical path from the tip to the sample contributes thermal drift. Furthermore, intrinsic properties of piezoelectric materials result in creep and hysteresis, which contribute to image distortion. The tip-sample interaction signals are often measured with optical configurations that require large free-space paths, are cumbersome to align, and add to the high cost of state-of-the-art SPM systems. These shortcomings have stifled the widespread adoption of SPMs by the nanometrology community. Tiny, inexpensive, fast, stable and independent SPMs that do not incur bandwidth penalties upon array scaling would therefore be most welcome. A method to increase the quality factor (Q-factor) of flexural resonators is introduced. The method relies on an internal energy pumping mechanism that is based on the interplay between electrical, iv mechanical, and thermal effects. To the best of the author's knowledge, the devices that are designed to harness these effects possess the highest electromechanical Qs reported for flexural resonators operating in air; electrically measured Q is enhanced from ~50 to ~50,000 in one exemplary device. A physical explanation for the underlying mechanism is proposed.The design, fabrication, imaging, and tip-based lithographic patterning with the first single-chip Scanning Thermal Microscopes (SThMs) are also presented. In addition to 3 DOF scanning, these devices possess integrated, thermally isolated temperature sensors to detect heat transfer in the tip-sample region.Imaging is reported with thermocouple-based devices and patterning is reported with resistive heater/sensors. An "isothermal electrothermal scanner" is designed and fabricated, and a method to operate it is detailed. The mechanism, based on electrothermal actuation, maintains a constant temperature in a central location while positioning a payload over a range of >35μm, thereby suppressing the deleterious thermal crosstalk effects that have thus far plagued thermally actuated devices with integrated sensors.

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“…In this model, the self-weight of the cantilever is assumed to uniformly distribute along the length, and the magnetic field source is equivalent to a uniform load applied within the area where the magnet is attached. The deflection [32] at the tip of the cantilever under an input acceleration (a input ) can be obtained as…”

Section: Design Of Force Field Coupling Structurementioning

confidence: 99%

High-Precision Acceleration Measurement System Based on Tunnel Magneto-Resistance Effect

Gao

Chen

Yao

et al. 2020

Sensors

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A high-precision acceleration measurement system based on an ultra-sensitive tunnel magneto-resistance (TMR) sensor is presented in this paper. A “force–magnetic–electric” coupling structure that converts an input acceleration into a change in magnetic field around the TMR sensor is designed. In such a structure, a micro-cantilever is integrated with a magnetic field source on its tip. Under an acceleration, the mechanical displacement of the cantilever causes a change in the spatial magnetic field sensed by the TMR sensor. The TMR sensor is constructed with a Wheatstone bridge structure to achieve an enhanced sensitivity. Meanwhile, a low-noise differential circuit is developed for the proposed system to further improve the precision of the measured acceleration. The experimental results show that the micro-system achieves a measurement resolution of 19 μg/√Hz at 1 Hz, a scale factor of 191 mV/g within a range of ± 2 g, and a bias instability of 38 μg (Allan variance). The noise sources of the proposed system are thoroughly investigated, which shows that low-frequency 1/f noise is the dominant noise source. We propose to use a high-frequency modulation technique to suppress the 1/f noise effectively. Measurement results show that the 1/f noise is suppressed about 8.6-fold at 1 Hz and the proposed system resolution can be improved to 2.2 μg/√Hz theoretically with this high-frequency modulation technique.

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An Analytical Capacitance Model of Temperature-Sensitive, Large-Displacement Multimorph Cantilevers: Numerical and Experimental Validation

Cited by 11 publications

References 31 publications

Tuning the oxygen functional groups in reduced graphene oxide papers to enhance the electromechanical actuation

Tuning the oxygen functional groups in reduced graphene oxide papers to enhance the electromechanical actuation

Single‐Chip Scanning Probe Microscopes

High-Precision Acceleration Measurement System Based on Tunnel Magneto-Resistance Effect

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