Bistable Cantilevers Actuated by Fringing Electrostatic Fields

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Naftaly Krakover ◽  
Slava Krylov
Keyword(s):  
Electrostatic Force ◽  
Thermal Sensitivity ◽  
Three Dimensional ◽  
Inertial Force ◽  
High Sensitivity ◽  
Initial Shape ◽  
Bistable Behavior ◽  
Plate Electrode ◽  
Cantilever Structure ◽  
Indeterminate Structures

Bistable microstructures are distinguished by their ability to stay in two different stable configurations at the same loading. They manifest rich behavior and are advantageous in applications such as switches, nonvolatile memories, and sensors. Bistability of initially curved or buckled double-clamped beams, curved plates, and shells is associated with mechanical geometric nonlinearity appearing due to coupling between bending and compressive axial/in-plane stress. The bistable behavior is achieved by using a combination of carefully tailored initial shape and constrained boundaries. However, these statically indeterminate structures suffer from high sensitivity to temperature and residual stress. In this work, we show using the model that by combining electrostatic actuation by fringing fields with direct transversal forcing by a parallel-plate electrode or piezoelectric (PZT) transducer, bistable behavior can be obtained in a simple cantilever structure distinguished by robustness and low thermal sensitivity. Reduced-order model of the cantilever was built using Galerkin decomposition, the electrostatic force was obtained by means of three-dimensional (3D) finite elements (FEs) modeling. We also demonstrate that operation of the device in the vicinity of the bistability threshold may enhance the frequency sensitivity of the cantilever to loading. This sensitivity-enhancement approach may have applications in a broad range of resonant microelectromechanical inertial, force, mass, and biosensors as well as in atomic force microscopy (AFM).

Numerical Simulation of the Flow and Heat Transfer Induced by Corona Discharge Coupling with Electrostatically Forced Vibration

2021 ◽  
Author(s):  
Yeng-Yung Tsui ◽  
Hao-Yu Lin ◽  
Ting-Kai Wei ◽  
Yu-Jie Huang ◽  
Chi-Chuan Wang
Keyword(s):  
Heat Transfer ◽  
Corona Discharge ◽  
Electrostatic Force ◽  
Three Dimensional ◽  
Resonant Mode ◽  
Finite Volume Methods ◽  
Flexible Plate ◽  
Ionic Wind ◽  
Plate Electrode ◽  
Oscillatory Movement

Abstract A thin, flexible plate electrode was adopted to generate both ionic wind and vibration in our previous study. The design contains a metal inductor placed next to the plate electrode so that it is attracted to vibrate by the induced electrostatic force. The resulting flow was used to enhance heat transfer. In this study, a numerical methodology is developed to unveil the flow structure induced by the corona discharge and electrode vibration. The oscillatory movement of the electrode is modeled as a cantilever beam vibrating at its first resonant mode. The electric and flow fields are solved by the finite volume methods. It is shown that a jet-like flow is generated by the electric discharge. The oscillatory movement of the jet results in flat temperature profile in comparison with the corona only system. Owing to the unsteady characteristic, the jet strength is less strong than that without vibration. The calculated results are qualitatively in line with the experiments, though some considerable differences exist. It is found that the oscillatory flow brings about lower overall heat transfer effectiveness than that without vibration regardless of the corona voltage. On the contrary, experiments showed that heat transfer is enhanced at low corona voltages where the ionic wind is not so overwhelming. The disagreement is mainly attributed to the 2-D assumption made in the simulation. The experimental arrangement, the corona discharge, and the vortex flows resulted all are three-dimensional. Therefore, 3-D calculations become necessary.

Efficient chemosensors for toxic pollutants based on photoluminescent Zn(II) and Cd(II) metal-organic networks

2021 ◽  
Author(s):  
Luis David Rosales-Vazquez ◽  
Alejandro Dorazco-González ◽  
Victor Sanchez-Mendieta
Keyword(s):  
Optical Sensors ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Environmental Research ◽  
Toxic Pollutants ◽  
Sensitivity And Selectivity ◽  
Metal Organic ◽  
Analytical Tools ◽  
Organic Networks

Optical sensors with high sensitivity and selectivity, as important analytical tools for chemical and environmental research, can be accomplished by straightforward synthesis of luminescent one-, two- and three-dimensional Zn(II) and...

scholarly journals A flexible and highly sensitive pressure sensor based on three-dimensional electrospun carbon nanofibers

RSC Advances ◽  
2021 ◽  
Vol 11 (23) ◽  
pp. 13898-13905
Author(s):  
Chuan Cai ◽  
He Gong ◽  
Weiping Li ◽  
Feng Gao ◽  
Qiushi Jiang ◽  
...  
Keyword(s):  
Carbon Nanofibers ◽  
Pressure Sensor ◽  
Carbon Nanofiber ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Highly Sensitive ◽  
Sensitive Pressure

A three-dimensional electrospun carbon nanofiber network was used to measure press strains with high sensitivity.

scholarly journals High-Performance On-Chip Silicon Beamsplitter Based on Subwavelength Metamaterials for Enhanced Fabrication Tolerance

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1304
Author(s):  
Raquel Fernández de Cabo ◽  
David González-Andrade ◽  
Pavel Cheben ◽  
Aitor V. Velasco
Keyword(s):  
Integrated Circuits ◽  
Fundamental Mode ◽  
High Performance ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Power Splitting ◽  
Excess Loss ◽  
Power Splitters ◽  
On Chip ◽  
Efficient Power

Efficient power splitting is a fundamental functionality in silicon photonic integrated circuits, but state-of-the-art power-division architectures are hampered by limited operational bandwidth, high sensitivity to fabrication errors or large footprints. In particular, traditional Y-junction power splitters suffer from fundamental mode losses due to limited fabrication resolution near the junction tip. In order to circumvent this limitation, we propose a new type of high-performance Y-junction power splitter that incorporates subwavelength metamaterials. Full three-dimensional simulations show a fundamental mode excess loss below 0.1 dB in an ultra-broad bandwidth of 300 nm (1400–1700 nm) when optimized for a fabrication resolution of 50 nm, and under 0.3 dB in a 350 nm extended bandwidth (1350–1700 nm) for a 100 nm resolution. Moreover, analysis of fabrication tolerances shows robust operation for the fundamental mode to etching errors up to ± 20 nm. A proof-of-concept device provides an initial validation of its operation principle, showing experimental excess losses lower than 0.2 dB in a 195 nm bandwidth for the best-case resolution scenario (i.e., 50 nm).

scholarly journals Pulsed Electromagnetic Cross-Well Exploration for Monitoring Permafrost and Examining the Processes of Its Geocryological Changes

Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 60
Author(s):  
Viacheslav Glinskikh ◽  
Oleg Nechaev ◽  
Igor Mikhaylov ◽  
Kirill Danilovskiy ◽  
Vladimir Olenchenko
Keyword(s):  
High Performance ◽  
Geophysical Methods ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Data Interpretation ◽  
Industrial Facilities ◽  
Wide Range ◽  
Vector Finite Element ◽  
A New Technique ◽  
Pulsed Electromagnetic

This paper is dedicated to the topical problem of examining permafrost’s state and the processes of its geocryological changes by means of geophysical methods. To monitor the cryolithozone, we proposed and scientifically substantiated a new technique of pulsed electromagnetic cross-well sounding. Based on the vector finite-element method, we created a mathematical model of the cross-well sounding process with a pulsed source in a three-dimensional spatially heterogeneous medium. A high-performance parallel computing algorithm was developed and verified. Through realistic geoelectric models of permafrost with a talik under a highway, constructed following the results of electrotomography field data interpretation, we numerically simulated the pulsed sounding on the computing resources of the Siberian Supercomputer Center of SB RAS. The simulation results suggest the proposed system of pulsed electromagnetic cross-well monitoring to be characterized by a high sensitivity to the presence and dimensions of the talik. The devised approach can be oriented to addressing a wide range of issues related to monitoring permafrost rocks under civil and industrial facilities, buildings, and constructions.

scholarly journals Development of a new method for assessing otolith function in mice using three-dimensional binocular analysis of the otolith-ocular reflex

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shotaro Harada ◽  
Takao Imai ◽  
Yasumitsu Takimoto ◽  
Yumi Ohta ◽  
Takashi Sato ◽  
...  
Keyword(s):  
Eye Movement ◽  
Three Dimensional ◽  
Vertical Component ◽  
Inertial Force ◽  
Linear Acceleration ◽  
The Body ◽  
Body Axis ◽  
Gravitational Acceleration ◽  
Ocular Reflex ◽  
Translational Movement

AbstractIn the interaural direction, translational linear acceleration is loaded during lateral translational movement and gravitational acceleration is loaded during lateral tilting movement. These two types of acceleration induce eye movements via two kinds of otolith-ocular reflexes to compensate for movement and maintain clear vision: horizontal eye movement during translational movement, and torsional eye movement (torsion) during tilting movement. Although the two types of acceleration cannot be discriminated, the two otolith-ocular reflexes can distinguish them effectively. In the current study, we tested whether lateral-eyed mice exhibit both of these otolith-ocular reflexes. In addition, we propose a new index for assessing the otolith-ocular reflex in mice. During lateral translational movement, mice did not show appropriate horizontal eye movement, but exhibited unnecessary vertical torsion-like eye movement that compensated for the angle between the body axis and gravito-inertial acceleration (GIA; i.e., the sum of gravity and inertial force due to movement) by interpreting GIA as gravity. Using the new index (amplitude of vertical component of eye movement)/(angle between body axis and GIA), the mouse otolith-ocular reflex can be assessed without determining whether the otolith-ocular reflex is induced during translational movement or during tilting movement.

Recent Developments In Monochromatic Microprobe X-Ray Fluorescence (MMXRF)

1998 ◽  
Vol 4 (S2) ◽  
pp. 378-379
Author(s):  
Z. W. Chen ◽  
D. B. Wittry
Keyword(s):  
Materials Science ◽  
High Vacuum ◽  
Three Dimensional ◽  
High Sensitivity ◽  
X Rays ◽  
Fluorescence Excitation ◽  
X Ray ◽  
Quantitative Microanalysis ◽  
Recent Developments ◽  
Fifth Order

A monochromatic x-ray microprobe based on a laboratory source has recently been developed in our laboratory and used for fluorescence excitation. This technique provides high sensitivity (ppm to ppb), nondestructive, quantitative microanalysis with minimum sample preparation and does not require a high vacuum specimen chamber. It is expected that this technique (MMXRF) will have important applications in materials science, geological sciences and biological science.Three-dimensional focusing of x-rays can be obtained by using diffraction from doubly curved crystals. In our MMXRF setup, a small x-ray source was produced by the bombardment of a selected target with a focused electron beam and a toroidal mica diffractor with Johann pointfocusing geometry was used to focus characteristic x-rays from the source. In the previous work ∼ 108 photons/s were obtained in a Cu Kα probe of 75 μm × 43 μm in the specimen plane using the fifth order reflection of the (002) planes of mica.

An Assessment of Three-Dimensional Turbulent Boundary Layer Prediction Methods

1973 ◽  
Vol 95 (3) ◽  
pp. 415-421 ◽  
Author(s):  
A. J. Wheeler ◽  
J. P. Johnston
Keyword(s):  
Boundary Layer ◽  
Eddy Viscosity ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Boundary Layer Flows ◽  
Mean Velocity ◽  
Eddy Viscosity Model ◽  
Separating Flow ◽  
Dimensional Boundary ◽  
Stress Models

Predictions have been made for a variety of experimental three-dimensional boundary layer flows with a single finite difference method which was used with three different turbulent stress models: (i) an eddy viscosity model, (ii) the “Nash” model, and (iii) the “Bradshaw” model. For many purposes, even the simplest stress model (eddy viscosity) was adequate to predict the mean velocity field. On the other hand, the profile of shear stress direction was not correctly predicted in one case by any model tested. The high sensitivity of the predicted results to free stream pressure gradient in separating flow cases is demonstrated.

Nanopillar modified high-sensitivity asymmetric Graphene-GaN photodetector

Nanoscale ◽  
2021 ◽  
Author(s):  
Chang Liu ◽  
Xiaodong Li ◽  
Tiangui Hu ◽  
Wenkai Zhu ◽  
Faguang Yan ◽  
...  
Keyword(s):  
Electrical Properties ◽  
High Performance ◽  
2D Materials ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Optical And Electrical Properties ◽  
Two Dimensional

Integration of two dimensional (2D) materials with three dimensional (3D) semiconductors reveals intriguing optical and electrical properties that surpass those of the original materials. Here we report the high performance...

Synthesis of ZrO2: Pr3+, Gd3+ nanocrystals for optical thermometry with thermal sensitivity above 2.32% K-1 over 270 K of sensing range

2021 ◽  
Author(s):  
Minghui Li ◽  
Jun Zhou ◽  
Ruoshan Lei ◽  
Huanping Wang ◽  
Feifei Huang ◽  
...  
Keyword(s):  
Thermal Sensitivity ◽  
High Sensitivity ◽  
Sensing Range ◽  
Optical Thermometry ◽  
Co Doped

Nowadays, there is an enthusiastic effort to develop the luminescent thermometers used for remote and high-sensitivity temperature readout over a wide sensing range. Herein, the Pr3+ and Gd3+ co-doped ZrO2...

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