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Nonlinear dynamical analysis of some microelectromechanical resonators with internal damping

Acta Mechanica Sinica 2021年第9期37卷 1457-1466,I0004页

作者： Dongming Wei Daulet Nurakhmetov Christos Spitas Almir Aniyarov Dichuan Zhang School of Sciences and Humanities Nazarbayev UniversityNur-Sultan010000Kazakhst School of Engineering Nazarbayev UniversityNur-Sultan010000Kazakhstan

In this paper, a new Kelvin-Voigt type beam model of a microelectromechanical resonator made of power-law materials taking into account internal strain-rate damping is proposed and the corresponding lumped-parameter model is derived. Analytical formulas of the lumped parameters in the model are presented. And the pull-in solution is analyzed based on the lumped-parameter model. It is demonstrated analytically and numerically that the internal damping plays an important role in the pull-in solution as well as in determination of the amplitudes and frequencies of the resonator. The hysteresis loops are provided for this model with initial conditions using numerical simulations. The approximation of the electrostatic force in the lumped-parameter model can describe the relations between amplitudes and frequencies with different values of the stiffness and damping coefficients quite well.

关键词： Power-law materials Euler-Bernoulli cantilever beam Lumped-parameter model microelectromechanical system Strain-rate damping

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Mode-localized accelerometer with ultrahigh sensitivity

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Science China(Information Sciences) 2022年第4期65卷 238-250页

作者： Hao KANG Bing RUAN Yongcun HAO Honglong CHANG Ministry of Education Key Laboratory of Micro and Nano systems for Aerospace School of Mechanical EngineeringNorthwestern Polytechnical University

The mode localization phenomenon is an effective technique to enhance sensor sensitivity,and some low noise floor mode-localized sensors,including accelerometers,mass sensors,and electrometers,have been successfully *** further improve the performance of the mode-localized accelerometer,we report a microelectromechanical system mode-localized accelerometer based on 4-degree of freedom （DoF） weakly coupled resonators （WCRs） with a stress-relief structure eliminating the thermal stress generated during the silicon-on-glass fabrication *** results show that compared with the state-of-the-art 3-DoF mode-localized accelerometer (4.40 g-1),the amplitude ratio-based sensitivity of the proposed accelerometer(119.36 V·g-1) is improved by 2612%.Moreover,the noise floor is 0.64μg·Hz-1/2from 0.01 to 3 Hz under the closed-loop *** the authors’best knowledge,this is the lowest measured noise floor for mode-localized accelerometers.

关键词： mode localization weakly coupled resonators accelerometer degree-of-freedom microelectromechanical system

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A prototype portable instrument employing micro-preconcentrator and FBAR sensor for the detection of chemical warfare agents

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Nanotechnology and Precision Engineering 2022年第1期5卷 43-48页

作者： Xu Yan Hemi Qu Ye Chang Wei Pang Xuexin Duan State Key Laboratory of Precision Measuring Technology and Instruments Tianjin UniversityTianjin 300072China College of Precision Instrument and Optoelectronics Engineering Tianjin UniversityTianjin 300072China Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education) Nankai UniversityTianjin 300071China

The presence of chemical warfare agents(CWAs)in the environment is a serious threat to human safety,but there are many problems with the currently available detection methods for *** example,gas chromatography–mass spectrometry cannot be used for in-field detection owing to the rather large size of the equipment required,while commercial sensors have the disadvantages of low sensitivity and poor ***,we develop a portable gas sensing instrument for CWA detection that consists of a MEMSfabricated micro-preconcentrator(μPC)and a film bulk acoustic resonator(FBAR)gas *** μPC is coated with a nanoporous metal–organic framework material to enrich the target,while the FBAR provides rapid detection without the need for extra carrier *** methylphosphonate(DMMP),a simulant of the chemical warfare agent sarin,is used to test the performance of the *** results show that the μPC provides effective sample pretreatment,while the FBAR gas sensor has good sensitivity to DMMP *** combination of μPC and FBAR in one instrument gives full play to their respective advantages,reducing the limit of detection of the ***,both the μPC and the FBAR are fabricated using a CMOS-compatible approach,and the prototype instrument is compact in size with high portability and thus has potential for application to in-field detection of CWAs.

关键词： Micro-preconcentrator Film bulk acoustic resonator Chemical warfare agent microelectromechanical system

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OPTICAL COHERENCE TOMOGRAPHY FOR BLADDER CANCER DIAGNOSIS:FROM ANIMAL STUDY TO CLINICAL DIAGNOSIS

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Journal of Innovative Optical Health Sciences 2008年第1期1卷 125-140页

作者： ZHIJIA YUAN HUGANG REN WAYNE WALTZER JASON KIM JINGXUAN LIU KEMIAO JIA HUIKAI XIE YINGTIAN PAN Departments of Biomedical Engineering Stony Brook UniversityStony BrookNYUSA Departments of Biomedical Urology Stony Brook UniversityStony BrookNYUSA Departments of Biomedical Pathology Stony Brook University Stony BrookNYUSA The ECE Department University of FloridaGainesvilleFLUSA

This paper summarizes the recent technological development in our lab on cystoscopic optical coherence tomography(COCT)by integrating time-domain OCT(TDOCT)and spectral-domain OCT(SDOCT)with advanced MEMS-mirror technology for endoscopic laser scanning *** COCT catheter can be integrated into the instrument channel of a commercial 22Fr rigid cystoscopic sheath for in vivo imaging of human bladder under the cystosocopic visual guidance;the axial/transverse resolutions of the COCT catheter are roughly 9μm and 12μm,respectively,and 2D COCT imaging can be performed with over 110dB dynamic range at 4–8 *** examine the utility and potential limitations of OCT for bladder cancer diagnosis,systemic ex vivo rat bladder carcinogenesis studies were performed to follow various morphological changes induced by tumor growth and in vivo porcine study was performed to examine the feasibility of COCT for in vivo *** by promising results of the animal studies,preliminary clinical study was conducted on patients scheduled for operating-room cystoscopy for bladder ***-blind clinical results reveal that COCT can delineate detailed bladder architectures(e.g.,urothelium,lamina propria,muscularis)at high resolution and detect bladder cancers based on enhanced urothelial heterogeneity as a result of excessive growing nature of bladder *** diagnostic sensitivity and specificity can be enhanced to 92%and 85%,*** also suggest that due to reduced imaging depth of COCT in cancerous lesions,staging of bladder cancers may be limited to Ta or T1 for non-outgrowing cancerous lesions.

关键词： Optical coherence tomography bladder cancer diagnosis microelectromechanical system

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Analytical modeling of self-powered electromechanical piezoelectric bimorph beams with multidirectional excitation

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International Journal of Smart and Nano Materials 2011年第3期2卷 134-175页

作者： M.F.Lumentut I.M.Howard Department of Mechanical Engineering Curtin UniversityAustralia

Unused mechanical energies can be found in numerous ambient vibration sources in industry including rotating equipment,vehicles,aircraft,piping systems,fluid flow,and even external movement of the human body.A portion of the vibrational energy can be recovered using piezoelectric transduction and stored for subsequent smart system utilization for applications including powering wireless sensor devices for health condition monitoring of rotating machines and defence communication *** vibration environment in the considered application areas is varied and often changes over time and can have components in three perpendicular directions,simultaneously or *** paper presents the development of analytical methods for modeling of self-powered cantilevered piezoelectric bimorph beams with tip mass under simultaneous longitudinal and transverse input base motions utilizing the weak and strong forms of Hamiltonian’s principle and space-and time-dependent eigenfunction series which were further formulated using *** reduced constitutive electromechanical equations of the cantilevered piezoelectric bimorph were subsequently analyzed using Laplace transforms and frequency analysis to give multi-mode frequency response functions(FRFs).The validation between theoretical and experimental results at the single mode of eigenfunction solutions reduced from multi-mode FRFs is also given.

关键词： microelectromechanical system piezoelectric energy harvesting smart sensor Hamiltonian strong weak and closed forms vibration

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