The results of experimental and theoretical studies of nonlinear acoustic phenomena (amplitude-dependent losses, resonant frequency shifts, damping of weak ultrasonic pulses and their carrier frequency phase delay under action of a powerful low-frequency pumping wave as well as amplitude-phase self-action of the finite-amplitude ultrasonic pulses) in a magnesite rod are presented. Analytical description of the observed phenomena was carried out within the frameworks of the phenomenological state equations that contain low-frequency hysteretic nonlinearity and both high-frequency dissipative and elastic nonlinearity. From comparison of experimental and analytical amplitude-frequency dependences of nonlinear phenomena, the values of magnesite acoustic nonlinearity parameters were determined. The frequency dependences have been discovered for hysteretic (in a range 3.6-17.2 kHz) as well as dissipative and elastic nonlinearity (in a range 50-370 kHz).
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http://dx.doi.org/10.1016/j.ultras.2013.07.008 | DOI Listing |
Ultrasonics
January 2025
Medical Ultrasound Department for the Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, Jiangsu 215163, China. Electronic address:
Shear Wave Elastography (SWE) is an imaging technique that detects shear waves generated by tissue excited by Acoustic Radiation Force (ARF), and characterizes the mechanical properties of soft tissue by analyzing the propagation velocity of shear wave. ARF induces a change in energy density through the nonlinear propagation of ultrasound waves, which drives the tissue to generate shear waves. However, the amplitude of shear waves generated by ARF is weak, and the shear waves are strongly attenuated in vivo.
View Article and Find Full Text PDFMicrosyst Nanoeng
January 2025
Institute of Novel Semiconductors, State Key Laboratory of Crystal Materials, Shandong University, 27 South Shanda Road, Shandong, 250100, P. R. China.
Acoustic frequency combs (AFCs) contain equidistant coherent signals with unconventional possibilities on metrology. Previously, implementation of AFCs on mechanical microresonators with large air damping loss is difficult, which restricted their atmospheric applications. In this work, we explore the potentials of a composite diamond/silicon microcantilever for parametric generation of AFCs in ambient air.
View Article and Find Full Text PDFJ Acoust Soc Am
January 2025
Audio Communication Group, Technische Universität Berlin, Einsteinufer 17c, Berlin, 10587 Germany.
Soundscape studies vary considerably in study design, statistical methods, and model fit metrics used. Due to this confounding of data and methods, it is difficult to assess the suitability of statistical modelling techniques used in the literature. Therefore, five different methods and two performance metrics were applied to three existing soundscape datasets to model soundscape Pleasantness and Eventfulness based on seven acoustic and three sociodemographic predictors.
View Article and Find Full Text PDFNano Lett
January 2025
Facultad de Ciencias Exactas y Naturales, Departamento de Física, Universidad de Buenos Aires, 1428 Buenos Aires, Argentina.
Nanostructured high-index dielectrics have shown great promise as low-loss photonic platforms for wavefront control and enhancing optical nonlinearities. However, their potential as optomechanical resonators has remained unexplored. In this work, we investigate the generation and detection of coherent acoustic phonons in individual crystalline gallium phosphide nanodisks on silica in a pump-probe configuration.
View Article and Find Full Text PDFUltrasonics
January 2025
College of Aerospace Engineering, Chongqing University, Chongqing 400044, China. Electronic address:
This study delves into the feasibility of leveraging quasi-static component (QSC) generation during primary Lamb wave propagation to discern subtle alterations in the interfacial properties of a two-layered plate. Unlike the second-harmonic generation of Lamb waves, QSC generation doesn't necessitate precise phase-velocity matching but rather requires an approximate matching of group velocities to ensure the emergence of cumulative growth effects. This unique characteristic empowers the QSC-based nonlinear ultrasonic method to effectively surmount the limitations associated with inherent dispersion and multimode traits of Lamb wave propagation.
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