Results 171 to 180 of about 2,219 (213)
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Novel tilt measurement method based on self-demodulated FBG sensor and pendulum clinometer
SPIE Proceedings, 2005A novel tilt measurement method is proposed based on self-demodulated fiber Bragg grating (FBG) sensor system, which consists of a couple of matched FBGs and a cantilever-based pendulum clinometer. With a cantilever structure, the tilt angle is measured by means of a differential form of Bragg wavelength shifting, with which the cross-sensitivity of ...
Jian Yang +4 more
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Fourier formalism for describing nonlinear self-demodulation of a primary narrow ultrasonic beam
The Journal of the Acoustical Society of America, 1990Presented here is the derivation of nonlinear interactions that occur within a primary narrow beam for which the temporal spectrum is continuous and narrow. This follows the bases of the Fourier formalism. Acoustics levels are presumed weak enough so that second-order equations may be used.
Pierre Cervenka, Pierre Alais
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Self-demodulation of acoustic pulses in the near zone of an acoustic radiator
Acoustical Physics, 2011The self-demodulation of acoustic pulses in the near zone of an acoustic radiator is studied both theoretically and experimentally. In the experiment, the aforementioned nonlinear process is studied for three types of biological tissues.
A. D. Mansfel’d +2 more
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The Journal of the Acoustical Society of America, 2007
Using a sensitive optical interferometer, the low frequency displacement nonlinearly generated by an ultrasonic tone burst propagating in a liquid is studied. Close to the source, the low frequency displacement contains a quasi-static component, which is affected by diffraction effects farther from the transducer.
Mathieu, Rénier +2 more
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Using a sensitive optical interferometer, the low frequency displacement nonlinearly generated by an ultrasonic tone burst propagating in a liquid is studied. Close to the source, the low frequency displacement contains a quasi-static component, which is affected by diffraction effects farther from the transducer.
Mathieu, Rénier +2 more
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A novel multi-functional fiber grating sensor with self-demodulation and discrimination capabilities
PICALO 2008: 3rd Pacific International Conference on Laser Materials Processing, Micro, Nano and Ultrafast Fabrication, 2008A low-cost but multi-functional fiber grating sensor with self-demodulation and discrimination capabilities is presented. The sensor can measure strain, vibration, normal temperature (-10-100°C), high temperature (100-800°C) and pressure. There are three fiber Bragg gratings (FBGs) and one fiber long period grating (LPG) in the sensor system.
Yage Zhan +4 more
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Ionospheric self-demodulation and self-distortion of radio waves
Journal of Atmospheric and Terrestrial Physics, 1959Abstract Experiments in which the phenomenon of ionospheric self-demodulation was investigated are described. Demodulation is observed to occur only at the lower modulation frequencies, and it is concluded that the occurrence of the phenomenon can be satisfactorily explained by an extension of Bailey 's theory of ionospheric cross-modulation as ...
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Temperature-compensated high pressure FBG sensor with a bulk-modulus and self-demodulation method
Sensors and Actuators A: Physical, 2005A free active element bulk-modulus based fiber Bragg grating (FBG) high pressure sensor and self-demodulation method for FBG wavelength shift signals are presented. With a simple isosceles triangle cantilever structure, problems of cross-sensitivity and chirped-signal in FBG sensor and are solved.
Jian Yang +3 more
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Japanese Journal of Applied Physics, 2015
A novel hearing aid system utilizing amplitude-modulated bone-conducted ultrasound (AM-BCU) is being developed for use by profoundly deaf people. However, there is a lack of research on the acoustic aspects of AM-BCU hearing. In this study, acoustic fields in the ear canal under AM-BCU stimulation were examined with respect to the self-demodulation ...
Kazuhito Ito, Seiji Nakagawa
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A novel hearing aid system utilizing amplitude-modulated bone-conducted ultrasound (AM-BCU) is being developed for use by profoundly deaf people. However, there is a lack of research on the acoustic aspects of AM-BCU hearing. In this study, acoustic fields in the ear canal under AM-BCU stimulation were examined with respect to the self-demodulation ...
Kazuhito Ito, Seiji Nakagawa
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Sensor Letters, 2007
A micro-vibration measurement method is proposed based on isostrain cantilever structure and cascade self-demodulated fiber Bragg grating (FBG) pair. The micro-vibration is measured with a cantilever structure which can induce a differential shift of FBG pair's Bragg wavelengths.
Jian Yang +4 more
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A micro-vibration measurement method is proposed based on isostrain cantilever structure and cascade self-demodulated fiber Bragg grating (FBG) pair. The micro-vibration is measured with a cantilever structure which can induce a differential shift of FBG pair's Bragg wavelengths.
Jian Yang +4 more
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Journal of Sound and Vibration, 2018
Abstract This work presents a fiber Bragg grating (FBG) displacement sensing system to experimentally investigate the dynamic behaviors of phononic crystal (PC) beams through impact-induced early short time or long time transient responses. Based on the couple-mode theory and the optical transfer matrix (T-matrix) formulation, we first show that it ...
Kuo-Chih Chuang +3 more
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Abstract This work presents a fiber Bragg grating (FBG) displacement sensing system to experimentally investigate the dynamic behaviors of phononic crystal (PC) beams through impact-induced early short time or long time transient responses. Based on the couple-mode theory and the optical transfer matrix (T-matrix) formulation, we first show that it ...
Kuo-Chih Chuang +3 more
openaire +1 more source