Results 171 to 180 of about 4,455,887 (219)
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Self-demodulation of elastic waves in a one-dimensional granular chain
Physical Review E, 2004The self-demodulation process in a nonlinear granular chain of identical beads is studied analytically and numerically. In such a medium, in accordance with the dispersion relation, longitudinal waves that have a frequency higher than the so-called cutoff frequency of the chain are evanescent.
V, Tournat, V E, Gusev, B, Castagnède
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Effect of self-demodulation on the subharmonic response of contrast agent microbubbles
Physics in Medicine and Biology, 2012Subharmonic (SH) emission from the ultrasound contrast agent (UCA) is of interest since it is produced only by the UCA and not by tissue, opposite to harmonic imaging modes where both tissue and microbubble show harmonics. In this work, the use of the self-demodulation (S-D) signal as a means of microbubble excitation at the SH frequency to enhance the
Daeichin, V +5 more
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Self-IQ-Demodulation Based Compensation Scheme of Frequency-Dependent IQ Imbalance for Wideband Direct-Conversion Transmitters [PDF]
IEEE Transactions on Broadcasting, 2015 A low cost frequency-dependent (FD) I/Q imbalance self-compensation scheme is investigated in this paper. The direct conversion transmitters are widely used in wireless systems.
Yue Zhang +2 more
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Self-Demodulated Heterodyne Frequency Domain Distributed Brillouin Fiber Sensor
IEEE Photonics Technology Letters, 2007We demonstrate a novel technique for Brillouin scattering-based distributed fiber sensing. The proposed technique is based on the use of two counterpropagating intensity-modulated optical signals, with their modulation frequencies differing by a small, fixed quantity. Stimulated Brillouin scattering leads to an optical demodulation of the probe signal,
R. BERNINI, MINARDO, Aldo, ZENI, Luigi
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The Journal of the Acoustical Society of America, 2021
Stable cavitation from microbubbles is important for both ultrasound-mediated therapy and contrast-enhanced imaging. Here, we extend the findings of prior studies, which indicate that the self-demodulation of the excitation pulse caused by nonlinear propagation can enhance stable cavitation.
null Vagisha +2 more
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Stable cavitation from microbubbles is important for both ultrasound-mediated therapy and contrast-enhanced imaging. Here, we extend the findings of prior studies, which indicate that the self-demodulation of the excitation pulse caused by nonlinear propagation can enhance stable cavitation.
null Vagisha +2 more
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Seismic Profiling with a Parametric, Self-Demodulated Ricker Wavelet
1987The nonlinear self-demodulation of a burst of high frequency sound produces a highly directive, low frequency transient in the parametric array process. Ricker wavelets, of interest in exploration seismology, can be generated from the self-demodulation of a primary pulsed in a Gaussian envelope.
T. G. Muir +3 more
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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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Optimized high frequency nonlinear contrast imaging using self-demodulation
2012 IEEE International Ultrasonics Symposium, 2012Previously we have shown that a suitable design of the excitation envelope to generate a self-demodulation (SD) signal at the subharmonic (SH) frequency can enhance the SH emission of ultrasound contrast agent (UCA) more than 20 dB at 10 MHz transmit frequency. The SH emission from the UCA is of interest since it is produced only by the UCA and is free
V. Daeichin +6 more
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Investigation of the process of self-demodulation of acoustic waves in the river sand
The Journal of the Acoustical Society of America, 1999Experimental investigation and theoretical description of nonlinear self-demodulation of a pulsed high-frequency acoustic wave and propagation of the secondary low-frequency acoustic pulses in dry and water-saturated sand are carried out. The dependence of the propagation time of the video pulses upon the initial static pressure and the relation of the
Veniamin E. Nazarov +2 more
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