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A multilayer structure of TeO2/interdigital transducers (IDTs)/ZnO(112¯0)/Si(100) was proposed and investigated to achieve both high sensitivity and temperature-stability for bio-sensing applications. Dispersions of phase velocities, electromechanical coupling coefficients K2, temperature coefficient of delay (TCD) and sensitivity in the multilayer structures were simulated as functions of normalized...
This paper has analyzed the relationship between the distribution of displacement vectors and the properties of corresponding line defect waveguide within the band gaps of PCs. In order to obtain the band gaps of PCs, a delay line model was built. Through simulating this model by finite element method, the displacement vectors in PCs also can be obtained. To analyze the properties of corresponding...
This paper has studied the influence of filling fraction on the band gaps of two-dimensional (2-D) piezoelectric phononic crystals (PnCs) in radio frequency (RF). The 2-D piezoelectric PnCs consists of tungsten (W) stubs on the finite slab of 128°YXLiNbO3 substrate. With Bloch periodic theorem, the single cell model was built using the three-dimensional (3-D) finite element method (FEM). Based on...
Carbon black combined PDMS is a promising material for laser ultrasonic inspection but the generated ultrasound field characteristics have not been studied. To obtain the wave field generated by laser in the polymer material, thermo-elasticity model was adopted, a 2D axial symmetry finite element model is built and the physics and parameters are set as actual situation for ultrasonic wave generation...
As a new structure, reflecting gratings based on two-dimensional (2-D) piezoelectric phononic crystals (PCs) have been studied for several years. This paper has proposed an approach to analyze the reflectivity of this reflecting grating in two directions. In the method, resonant modal was firstly analyzed with three-dimensional (3-D) finite element method (FEM) using the commercial software COMSOL...
A three-dimensional (3D) finite element method (FEM) model was proposed to analyze the resonant modal of the transducers based on two-dimensional (2D) phononic crystals (PnCs). Using this model two modals existed with symmetric modal and anti-symmetric modal can be extracted, and then reflectivity of the transducers was derived. An example of transducer based on 2D PnCs composed of IDTs of aluminum...
This paper has proposed a weighted waveguide for surface acoustic waves (SAW) based on two-dimensional piezoelectric phononic crystals (PnCs). In order to analyze the transmission of the weighted waveguide based on PnCs, SAW delay line model was built. In the model, period boundary condition was adopted to reduce the time and memory of model cost and perfect matching layer was adopted to absorb the...
The impacts of two immobilization methods, which are Biotin-avidin system (BAS) and Self-assembled monolayer technology (SAM), made on the performance of aptasensors in terms of acoustics were analyzed through experiment. Love-wave aptasensors were designed by coupling aptamers to the surface of a Love-wave sensor with the two methods respectively. Abrin is chosen as the analyte. For certain concentrations...
This paper aimed to study the pressure sensitive coefficients of different cuts of quartz for the surface acoustic wave(SAW) pressure sensors with non-uniform pressure load, and tried to find the most sensitive cut. The finite element analysis/ perturbation theory combines model was constructed to calculate the pressure sensitive coefficients. For analysis of different cut angles (0, θ, φ) of quartz...
Phononic crystals (PCs) have promising band gaps, in which Surface Acoustic Wave (SAW) propagating is prohibited. Several numerical methods have already been developed and applied to analyze piezoelectric PCs, most of them have various disadvantages, as they cannot calculate the transmission characteristic of the limited structure or cannot provide the propagation process for SAW in time domain. The...
A surface acoustic wave (SAW)-based sensor coated with SnO2 thin layer is investigated for H2S sensing. The conventional semiconductor sensor usually works in higher temperature (>;150°C) by resistance effect and performs with low sensitivity (>;10ppm). Compared with conventional semiconductor sensor, the SAW-based sensor is affected not only by conductivity but also by mass loading. Both of...
A love-wave biosensor has been designed by coupling aptamers to the Au-surface of sensor chip. Aptamers are artificial nucleic acid ligands that can be obtained in the process of SELEX. Aptamers have advantages over antibodies, such as high affinity, specificity, and stability. As Love waves' acoustic energy is confined to a thin near-surface region of substrate by guiding layer, Love wave sensors...
In the paper, takes three-A level hospital in Jiangxi province as an example, based on the survey in the concrete hospital and systematic analysis on hospital actual situation, with the help of the literature review, research methodology and analytical framework of the competitiveness, the paper established the main influencing factors that acted on the hospital competitiveness, then on the basis...
The paper introduces a rigorous numerical model to analyze SAW (surface acoustic wave) resonators by BEM (boundary element method). At first it is proposed that the mass-loading effect of electrode is neglected and the surface of substrate is free, and the substrate is semi-infinite. Then corresponding programs are developed to analyze a SAW resonator. Electrical charge distribution on the electrode-substrate...
Highway airstrips construct the airport net with stock airports and standby airports as assistant, and the icing condition of airstrip surface need be monitored. Surface acoustic wave(SAW) ice sensor is in small size and can wireless passive measure, potential in highway airstrip ice monitoring application. Based on Zimmermann's theory, the impacts of guiding layer thickness on phase velocity was...
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