Topic
Acoustic interferometer
About: Acoustic interferometer is a research topic. Over the lifetime, 1493 publications have been published within this topic receiving 19355 citations.
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TL;DR: A point source-point receiver technique, based on laser generation and laser detection of acoustic waves, allows determination of mechanical properties of an anisotropic cylinder and the identification of the stiffness tensor components is applied to signals simulated for a composite material.
3 citations
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25 Jun 1995
TL;DR: In this paper, the results of an In203 coated surface acoustic wave (SAW) sensor for ozone monitoring are presented, where the transduction mechanism is based on film conductivity changes, not on the mass loading effect.
Abstract: In this paper we present our current work towards the development of gas sensors for environmental monitoring based on semiconducting oxide coated Surface Acoustic Wave (SAW) devices. The results for an In203 coated SAW sensor for ozone monitoring are presented. The transduction mechanism is based on film conductivity changes, not on the mass loading effect. INTRODUCT1C)N The release of chemical pollutants to the atmosphere from industrial, agricultural and natural processes is the cause of the enhanced greenhouse effect and ozone depletion. In order to monitor the amount of gas emissions from the different sources, analytical techniques are currently being used. A number of new techniques, imd improvements to current techniques could considerably reduce the uncertainties in the gas exchange determination [I]. Through the development of gas sensors to detect various air pollutants with reversibility and reproducibility these requirements can be met. Current research shows that semiconducting oxides provide an optimum basis for this sensing application. Thin films based on Sn02, In203 and WO3 have been successfully applied to sensing CO, NO,, 03-, CH4 amongst others, showing a change in the conductivity related to the gas concentration [2]. Surface Acoustic Wave gas sensors, based on the acoustoelectric interaction between the SAWS and semiconductive selective film, offer an alternative to conductance or resistance measurements [3]. When a semiconducting oxide film is deposited on a SAW delay line working in an oscillator configuration (figure 1) one can observe variations of the oscillator frequency that depend on the variations of the selective film conductivity as: where Af and AV are the absolute ck of the device and velocity of the SP of the oscillator, vo is the SAM piezoelectric coupling constant of tl surface conductivity of the film an( Cs is the static capacitance per unit surface. According to the above changes in the velocity will occur or IDT IDT J selective film
3 citations
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TL;DR: In this paper, nonlinear interactions between collinear bulk acoustic waves of orthogonal polarizations have been used to perform convolution and correlation in a non-piezoelectric crystal.
Abstract: Nonlinear interactions between collinear bulk acoustic waves of orthogonal polarizations have been used to perform convolution and correlation in a nonpiezoelectric crystal. The analysis of the device operation and experimental results are reported.
3 citations
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TL;DR: In this paper, the authors demonstrate the existence of exotic absorption peaks when acoustic wave propagates through a one-dimensional layered phononic crystal (PC) at frequencies within the band gap into a material of large acoustic impedance mismatch.
Abstract: In this article, we demonstrate the existence of exotic absorption peaks when acoustic wave propagates through a one-dimensional layered phononic crystal (PC) at frequencies within the band gap into a material of large acoustic impedance mismatch. By analyzing the displacement field distribution, it indicates that the absorption peaks are due to the excitation of the resonant interface states at boundary between the last layer of the PC and emergent material. The number of period and the thickness of last layer of the PC play the decisive role in determining the magnitude and frequency of absorption peaks. And the absorptivity can be nearly unity with a reasonable design of the structure. Specifically, these absorption peaks would almost disappear when the incident direction of acoustic waves is reversed. This property can be employed to design an acoustic wave unidirectional absorption device.
3 citations
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TL;DR: In this paper, the authors have set up an apparatus for stress measurements, applied it to Ni plates with different residual stresses, and have obtained output signals corresponding to different stresses, which makes it possible to know the stress state in structures before the formation of cracks, and hence offers a very promising nondestructive testing device.
Abstract: In magnetic substances under oscillating stress due to the application of acoustic waves (such as ultrasonic waves), an oscillating anisotropic field may be generated by the inverse effect of magnetostriction. If this magnetic field oscillation can be detected, the stress state inside the magnetic substance can be determined. Based upon this principle, we have set up an apparatus for stress measurements, applied it to Ni plates with different residual stresses, and have obtained output signals corresponding to different stresses. This measuring technique makes it possible to know the stress state in structures before the formation of cracks, and hence offers a very promising nondestructive testing device.
3 citations