scholarly journals Energy Dissipation Contribution Modeling of Vibratory Behavior for Silicon Micromachined Gyroscope

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
J. Zhou ◽  
Q. Shen ◽  
J. B. Xie ◽  
P. P. Cao ◽  
W. Z. Yuan
Keyword(s):  
Numerical Calculation ◽  
Energy Dissipation ◽  
Design Stage ◽  
Temperature Dependent ◽  
Vibratory Gyroscope ◽  
Air Damping ◽  
Temperature And Pressure ◽  
Micromachined Gyroscope ◽  
Quality Factor Q ◽  
Anchor Loss

Energy dissipation contribution of micro-machined Coriolis vibratory gyroscope (MCVG) is modeled, numerically simulated, and experimentally verified in this paper. First, the amount of independent damping dissipation consisting of thermoelastic loss, anchor loss, surface loss, Akhiezer loss, and air damping loss during vibration is obtained by simulation model, PML-based method, and numerical calculation, respectively. Then, temperature and pressure dependence characteristic of the corresponding quality factor (Q) for the MCVG are obtained. Meanwhile, dominant sources of damping dissipation are determined, which paves the way to improve Q. Finally, the temperature-dependent and pressure-dependent characteristics of the total Q are measured with errors of less than 10% and 18% compared with the simulated total Q, respectively, in which accuracy is acceptable for predicting the damping dissipation behavior of MCVG in design stage before high-cost fabrication.

On the Temperature Dependence of Resistivity of Polycrystalline Silicon Films

1987 ◽  
Vol 106 ◽  
Author(s):  
Mark S. Rodder ◽  
Dimitri A. Antoniadis
Keyword(s):  
Numerical Calculation ◽  
Polycrystalline Silicon ◽  
Amorphous Region ◽  
Defect States ◽  
Temperature Dependent ◽  
Step Process ◽  
Dependent Potential ◽  
Si Films ◽  
Polycrystalline Silicon Films ◽  
P Type

ABSTRACTIt is shown that the grain boundary (GB) in polycrystalline-silicon (poly-Si) films need not be modeled as a temperature-dependent potential barrier or as an amorphous region to explain the temperature (T) dependence of resistivity (ρ) in p-type poly-Si films at low T. Specifically, we consider that QB defect states allow for the tunneling component of current to occur by a two-step process. Incorporation of the two-step process in a numerical calculation of ρ vs. T results in excellent agreement with available data from 100 K to 300 K.

Design and Simulation of Capacitive Micromechaned Gyroscope

2011 ◽  
Vol 211-212 ◽  
pp. 909-913
Author(s):  
Yun Bo Shi ◽  
Xing Juan Zhao ◽  
Jun Tang ◽  
Jun Liu ◽  
Rui Rong Wang
Keyword(s):  
Atmospheric Pressure ◽  
Simulation Analysis ◽  
High Sensitivity ◽  
Drive Mode ◽  
Close Match ◽  
High Q ◽  
Air Damping ◽  
Large Numbers ◽  
Detection Mode ◽  
Micromachined Gyroscope

By researching and investigating the structure of capacitive gyroscopes, A novel capacitive micromachined gyroscope is proposed and the structure is designed. The method of electrostatic comber drive, capacitive detection of bar structure is used for the structure, and these make the gyroscope high sensitivity. The main air damping of the drive mode and detection mode is slide film damping, it is possible to make the gyroscope achieve high Q-values at atmospheric pressure. The decoupled gyroscope is designed, too. By large numbers of simulation analysis， frequencies of the first six steps mode are gained, nature frequencies of drive mode and sense mode of gyroscope are a close match, and rationality of the structure is validated. At last, the structure encapsulated is presented.

scholarly journals Monitoring the temperature-dependent elastic and anelastic properties in isotropic polycrystalline ice using resonant ultrasound spectroscopy

2016 ◽  
Vol 10 (6) ◽  
pp. 2821-2829 ◽  
Author(s):  
Matthew J. Vaughan ◽  
Kasper van Wijk ◽  
David J. Prior ◽  
M. Hamish Bowman
Keyword(s):  
Sea Ice ◽  
Ice Cores ◽  
Compressional Wave ◽  
Temperature Dependent ◽  
Resonant Ultrasound Spectroscopy ◽  
Polycrystalline Ice ◽  
Passive Seismic ◽  
Resonant Ultrasound ◽  
Increasing Temperature ◽  
Quality Factor Q

Abstract. The elastic and anelastic properties of ice are of interest in the study of the dynamics of sea ice, glaciers, and ice sheets. Resonant ultrasound spectroscopy allows quantitative estimates of these properties and aids calibration of active and passive seismic data gathered in the field. The elastic properties and anelastic quality factor Q in laboratory-manufactured polycrystalline isotropic ice cores decrease (reversibly) with increasing temperature, but compressional-wave speed and attenuation prove most sensitive to temperature, indicative of pre-melting of the ice. This method of resonant ultrasound spectroscopy can be deployed in the field, for those situations where shipping samples is difficult (e.g. remote locations), or where the properties of ice change rapidly after extraction (e.g. in the case of sea ice).

scholarly journals A Study on the Trimming Effects on the Quality Factor of Micro-Shell Resonators Vibrating in Wineglass Modes

Micromachines ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 695
Author(s):  
Lu ◽  
Xi ◽  
Xiao ◽  
Shi ◽  
Zhuo ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Quality Factor ◽  
Second Harmonic ◽  
Great Influence ◽  
Fem Simulation ◽  
Q Factor ◽  
Thermoelastic Damping ◽  
Frequency Trimming ◽  
Quality Factor Q ◽  
Anchor Loss

Frequency trimming based on mass and stiffness modification is an important post-fabrication process for micro-shell resonators (MSRs). However, the trimming effects on the quality factor are seldom studied, although they may have great influence on the performance of the resonator. This paper presents a study on the quality factor (Q-factor) variation of trimmed micro-shell resonators (MSR). Thermoelastic damping (QTED) and anchor loss (Qanchor) are found to be the dominant energy loss mechanisms resulting in the reduction of the overall Q-factor, according to finite element method (FEM). The effects of different trimming methods on QTED and Qanchor are studied here, respectively. It is found that trimming grooves ablated in the rim of the resonator can cause a ~1–10% reduction of QTED, and the length of trimming groove is positively related to the reduction of QTED. The reduction of QTED caused by the mass adding process is mainly related to the thermal expansion coefficient and density of the additive and contact area between the resonator and additive masses. Besides, the first and second harmonic errors caused by asymmetrical trimming can cause a 10–90% reduction of Qanchor. Finally, trimming experiments were conducted on different resonators and the results were compared with FEM simulation. The work presented in this paper could help to optimize the trimming process of MSRs.

scholarly journals Effects of temperature on performance of compressible magnetorheological fluid suspension systems

2017 ◽  
Vol 29 (1) ◽  
pp. 41-51 ◽  
Author(s):  
Michael McKee ◽  
Faramarz Gordaninejad ◽  
Xiaojie Wang
Keyword(s):  
Theoretical Model ◽  
Energy Dissipation ◽  
Bulk Modulus ◽  
Temperature Effect ◽  
Magnetorheological Fluid ◽  
Suspension System ◽  
Shear Yield Stress ◽  
Temperature Dependent ◽  
Suspension Systems ◽  
Shear Yield

The temperature effect on performance of compressible magnetorheological fluid suspension systems is studied. Magnetorheological fluid is a temperature-dependent material where its compressibility and rheological properties change with temperature. Experimental studies were conducted to explore the temperature effects on the properties of the magnetorheological fluid and the compressible magnetorheological fluid suspension systems. The temperature effect on magnetorheological fluid properties included the bulk modulus, shear yield stress, and viscosity. It was found that the shear yield stress of the magnetorheological fluid remains unchanged within the testing range while both the plastic viscosity, using the Bingham plastic model, and the bulk modulus of the magnetorheological fluid decrease as the temperature of the fluid increases. A theoretical model that incorporates the temperature-dependent properties of magnetorheological fluid was developed to predict behavior of a compressible magnetorheological fluid suspension system. An experimental study was conducted using an annular flow compressible magnetorheological fluid suspension system with varying temperatures, motion frequencies, and magnetic fields. The experimental results are used to verify the theoretical model. Moreover, the stiffness and energy dissipation of the compressible magnetorheological fluid suspension system were obtained, experimentally. The effects of the temperature on performance characteristics of the compressible magnetorheological fluid suspension system were analyzed. It was found that both the stiffness and the energy dissipation decrease with an increase in the temperature of magnetorheological fluid.

Examination of pre-industrial and future [CO2] reveals the temperature-dependent CO2 sensitivity of light energy partitioning at PSII in eucalypts

2010 ◽  
Vol 37 (11) ◽  
pp. 1041 ◽  
Author(s):  
Barry A. Logan ◽  
Carolyn R. Hricko ◽  
James D. Lewis ◽  
Oula Ghannoum ◽  
Nathan G. Phillips ◽  
...  
Keyword(s):  
Electron Transport ◽  
Energy Dissipation ◽  
Fluorescence Emission ◽  
Photosynthetic Electron Transport ◽  
Co2 Assimilation ◽  
Energy Partitioning ◽  
O2 Evolution ◽  
Tree Seedlings ◽  
Temperature Dependent ◽  
Photosynthetic O2 Evolution

We grew faster-growing Eucalyptus saligna Sm. and slower-growing Eucalyptus sideroxylon A. Cunn ex Woolls tree seedlings in sunlit glasshouses at all combinations of 290 µL L–1 (pre-industrial), 400 µL L–1 (modern) or 650 µL L–1 (future) global atmospheric CO2 ([CO2]), and ambient or ambient + 4°C temperature. To assess photosynthetic performance, we simultaneously measured light-saturated CO2 assimilation (Asat) and chlorophyll fluorescence emission along with the capacity for photosynthetic O2 evolution and leaf pigment composition. Photosynthetic response to [CO2] was similar between species. Increasing [CO2] but not temperature increased Asat. The response of photosynthetic electron transport to [CO2] was temperature-dependent and manifested through adjustments in energy partitioning at PSII. Increasing [CO2] resulted in greater PSII operating efficiencies at the elevated temperature. We observed no associated acclimatory adjustments in the capacity for photosynthetic O2 evolution or changes in leaf chlorophyll content. Photoprotective energy dissipation responded to increasing [CO2] and temperature. Across species and treatments, increased energy partitioning to electron transport was always associated with decreased partitioning to energy dissipation. Our results suggest that in response to increasing [CO2] and temperature, E. saligna and E. sideroxylon meet increased demands for the products of electron transport via adjustments in energy partitioning, not through acclimation of the capacity for photosynthetic electron transport or light absorption.

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