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Acoustic focusing by coiling up space
Applied Physics Letters, 2012We report the design of a gradient index acoustic lens by coiling up space, an entirely different, yet more direct approach compared with previous designs. The proposed model comprises a series of acoustic metamaterial units with curled channels. Acoustic waves propagate freely within the channels but their propagating phases can be delayed at will by ...
Yong Li +5 more
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Acoustic focusing using efficient ultrasonic metagratings
The Journal of the Acoustical Society of America, 2020Metagratings are periodic arrays of rationally designed elements with engineered scattering properties. In contrast to gradient meta-surfaces, a much less dense array of elements is required, and efficient refraction or reflection is possible for very large angles.
Yan Kei Chiang +4 more
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Meteorological Focusing of Acoustic Energy
Sound: Its Uses and Control, 1963Meteorological focusing of acoustic energy by calculating acoustic ray paths, to be used as a method of noise ...
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A circularly focused and scanned acoustic scanner
IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 1999This paper describes a new type of electronically scanned and focused acoustic imaging device called the cylindrical grating acoustic scanner. With this device, a new transducer called the circular-edge-bonded transducer (CEBT) is devised that is bonded on one end of a cylindrical substrate and can generate a surface acoustic wave propagating along the
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Reconfigurable ultrasound focusing effect through acoustic barriers
UltrasonicsThe low transmission efficiency of ultrasonic waves in waveguides of a high acoustic impedance (referred to as dense materials), due to the impedance mismatch between the background media and the dense materials, poses a significant obstacle to practical applications of high-intensity focused ultrasound (HIFU) such as ultrasound therapy or medical ...
Ming, Ma +3 more
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Ultrasonic focused waveform generation using time reversal acoustic focusing system
Journal of Mechanical Science and Technology, 2008Abstract The concept of Time Reversal Acoustics (TRA) provides an elegant possibility of both temporal and spatial concentrating of acoustic energy in highly inhomogeneous media. We explored the possibility of generating acoustical signals with arbitrary waveforms using the TRA Focusing System (TRA FS).
Bok Kyoung Choi +3 more
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Optimum acoustic frequency for focused ultrasound surgery
Ultrasound in Medicine & Biology, 1994A model is described that enables calculation of ultrasound lesioning rate (inverse of time to achieve a threshold lesion in the absence of thermal redistribution) as a function of acoustic frequency, tissue penetration depth, d, attenuation coefficient at specific frequency, mu, and power of dependence of attenuation on frequency, n.
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Solid Plate Acoustical Wave Focusing
1975This paper is devoted to the operating procedures of solid plate wave focusing, the heart of the solid plate acoustical viewer, first presented at the Fifth International Symposium. The waves are the imaging device somewhat akin to the focused electronic signals in a television display, the next to last step in the viewing procedure by acoustical ...
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Acoustically focusing and measuring biological cells
2023In the 1990s, thousand-year-old mummies were exhumed at an excavations site in the southern tip of Peru. The exhumed mummies included the mummified body of a woman in her mid thirties who presented an abnormal growth on the bone of her upper arm. Such bone tumors are classified as an orphan disease due to their low prevalence in the general public ...
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Acoustic metagrating focusing and Bessel vortexes
Applied Physics LettersAcoustic focusing and Bessel vortexes have great potential in medical ultrasound, particle trapping, and information processing. Based on the generalized Snell's law (GSL), metasurface focusing and Bessel vortexes were achieved by using in-plane phase profiles to shape wavefronts.
Ke-qi Zhao +7 more
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