Mass loading effect of shock accelerometers

2005 ◽  
Vol 117 (4) ◽  
pp. 2386-2386
Author(s):  
Lixue Wu ◽  
George S. K. Wong ◽  
Peter Hanes ◽  
Won‐Suk Ohm
Keyword(s):  
Mass Loading ◽  
Loading Effect

Investigation on Resonance Effects of Closely Resonating Nano-Pillars Attached to SAW Resonator

2011 ◽  
Vol 403-408 ◽  
pp. 1183-1187
Author(s):  
N. Ramakrishnan ◽  
Harshal B. Nemade ◽  
Roy Paily Palathinkal
Keyword(s):  
Acoustic Wave ◽  
Resonance Frequency ◽  
Frequency Shift ◽  
Fem Simulation ◽  
Mass Loading ◽  
Loading Effect ◽  
Resonance Effects ◽  
Additional Information ◽  
Resonance Frequency Shift ◽  
Small Change

Surface acoustic wave (SAW) sensors form an important class of micro sensors in the microelecto mechanical systems (MEMS) family. Mass loading effect of a sensing medium is one of the prime sensing principles in SAW sensors. Recently we reported mass loading effect of high aspect ratio nano-pillars attached to a SAW resonator. We observed increase in resonance frequency of the SAW resonator in addition to the general mass loading characteristics. We concluded that when the resonance frequency of the pillar is equal to the SAW resonator frequency, the resonance frequency shift caused by mass loading of pillar tends to a negligible value. When such resonating pillars are used as sensing medium in SAW sensors, even a very small change in the dimension of the pillar will offer significant resonance frequency shift. Accordingly, high sensitive SAW sensors can be developed. However in practice it’s quite difficult to manufacture nano-pillars with accurate dimensions such that they resonate with SAW resonator. There is more probability that the pillars may closely resonate with SAW device and offer mass loading. In the present work we have extended our earlier work and performed finite element method (FEM) simulation to study the insight physics of the closely resonating pillars and their effects on acoustic wave propagating on SAW substrate. In this paper we present the discussion on the resonance effects of typical closely resonating pillars on resonance frequency spectrum of the SAW resonator and observations in the pressure wave at the contact surface of the pillar and SAW resonator substrate. It is observed that when the nano-pillars closely resonate with SAW resonator, the pillar oscillations combine with waves propagating in the substrate and introduce beat frequencies. The results and discussion of this paper adds additional information in designing SAW based coupled resonating systems.

Improved Prediction of Electrodes’ Mass Loading Effect on MEMS FBAR Structure in Longitudinal Resonance

2008 ◽  
Author(s):  
Annie Ruimi ◽  
Yueming Liang ◽  
Robert M. McMeeking
Keyword(s):  
Finite Elements ◽  
Aluminum Nitride ◽  
Resonant Frequency ◽  
Layer Thickness ◽  
Piezoelectric Layer ◽  
Numerical Scheme ◽  
Three Dimensional ◽  
Mass Loading ◽  
Loading Effect ◽  
One Dimensional

In this paper, we derive an exact one-dimensional rule for predicting mass loading effect due to electrodes by analyzing a FBAR structure consisting of a piezoelectric layer and two electrodes in longitudinal resonance. We validate the numerical scheme using aluminum nitride as the piezoelectric material and gold and aluminum for the top and bottom electrodes respectively. Results are compared with three-dimensional finite elements simulations obtained earlier. It is seen that the new rule predicts higher values of the resonant frequency and constitutes an improvement over an elementary rule particularly for electrodes thicknesses greater than 20% of the piezoelectric layer thickness.

The magnetic flux transport along the -Esw direction in the magnetotails on Mars and Venus

2020 ◽  
Author(s):  
Lihui Chai ◽  
James Slavin ◽  
Yong Wei ◽  
Weixing Wan ◽  
Charlie F. Bowers ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Magnetic Flux ◽  
Pressure Gradient ◽  
Plasma Sheet ◽  
Magnetic Pressure ◽  
Mass Loading ◽  
Flux Transport ◽  
Loading Effect

<p>The induced magnetotails on Mars and Venus are considered to arise through the interplanetary magnetic field (IMF) draping around the planet and the solar wind deceleration due to the mass loading effect. They have very similar structures as that on Earth, two magnetic lobes of opposite radial magnetic fields and a plasma sheet in between. However, the orientation and geometry of the induced magnetotails are controlled by the IMF, not the planetary intrinsic magnetic field. In this study, we present another characteristic of the induced magnetotails on Mars and Venus with the observations of MAVEN and Venus Express. It is found that the magnetic flux in the induced magnetotails on Mars and Venus are inhomogeneous. There is more magnetic flux in the +E hemisphere than -E hemisphere. The magnetic flux is observed to transport gradually from the +E hemisphere to the -E hemisphere along the magnetotail. The magnetotail magnetic flux transport seems to be faster on Mars than that at Venus. Based on these observations, we suggest that the finite gyro-radius effect of the planetary ions that are picked up by the solar wind is responsible to the magnetic flux inhomogeneity and transport in the induced magnetotails. The role of the magnetic pressure gradient in the magnetotail will be discussed.</p>

scholarly journals Asymmetric mass loading effect at Titan's ionosphere

2001 ◽  
Vol 106 (A5) ◽  
pp. 8323-8332 ◽  
Author(s):  
Andreas Kopp ◽  
Wing-Huen Ip
Keyword(s):  
Mass Loading ◽  
Loading Effect

Mass-loading effect on quality factor of floppy silicon microcantilever in free air space

2011 ◽  
Vol 6 (2) ◽  
pp. 62-65 ◽  
Author(s):  
Yong Liu ◽  
Gang Zhao ◽  
Li Wen ◽  
Xingzhong Xu ◽  
Jiaru Chu
Keyword(s):  
Quality Factor ◽  
Mass Loading ◽  
Loading Effect ◽  
Free Air ◽  
Air Space
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