Piezoelectric micromachined ultrasonic transducers (PMUTs) are a promising alternative to conventional bulk piezoelectric ceramic-based ultrasonic transducers. However, the transmitting sensitivity of the reported PMUTs is far from satisfactory. In this paper, we report a beam-membrane coupled PMUT (BM-PMUT), which enhances the transmitting sensitivity via simultaneously increasing the acoustic emission areas and maintaining the comparable vibration amplitude. Experimental results show that the center and edge transmitting sensitivities of the BM-PMUT are 108.1 and 96 nm/V at 370 kHz, which are 109.9 and 49.6 nm/V at 677 kHz for the traditional PMUT (T-PMUT). Thus, the BM-PMUT realizes piston-like mode shapes and achieves around twofold improvement in the effective acoustic emission area relative to the traditional T-PMUT of the same size. Due to the larger acoustic emission areas and comparable vibration amplitudes, the normalized far-field sound pressure level of the BM-PMUT is 8.5 dB higher than that of the T-PMUT.
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http://dx.doi.org/10.3390/mi13030423 | DOI Listing |
Eur Radiol
January 2025
Department of Information Technology, Uppsala University, 75237, Uppsala, Sweden.
Objectives: The aim is to assess the feasibility and accuracy of a novel quantitative ultrasound (US) method based on global speed-of-sound (g-SoS) measurement using conventional US machines, for breast density assessment in comparison to mammographic ACR (m-ACR) categories.
Materials And Methods: In a prospective study, g-SoS was assessed in the upper-outer breast quadrant of 100 women, with 92 of them also having m-ACR assessed by two radiologists across the entire breast. For g-SoS, ultrasonic waves were transmitted from varying transducer locations and the image misalignments between these were then related analytically to breast SoS.
Ultrasonics
January 2025
Department of Civil Engineering and Architecture, Tallinn University of Technology, Ehitajate tee 5, 19086, Tallinn, Estonia. Electronic address:
Pipe bends are recognized as critical areas susceptible to wall thinning, a phenomenon instigated by abrupt changes in the fluid flow direction and velocity. Conventional monitoring techniques for bends typically depend on localized ultrasonic measurements of thickness. While these methods are effective, they can be time-consuming compared to the use of permanently installed transducers, a strategy employed in guided wave tomography (GWT).
View Article and Find Full Text PDFSensors (Basel)
December 2024
School of Instrument and Electronics, North University of China, Taiyuan 030051, China.
Tire pressure monitoring systems (TPMSs) are essential for maintaining driving safety by continuously monitoring critical tire parameters, such as pressure and temperature, in real time during vehicle operation. Among these parameters, tire pressure is the most significant, necessitating the use of highly precise, cost-effective, and energy-efficient sensing technologies. With the rapid advancements in micro-electro-mechanical system (MEMS) technology, modern automotive sensing and monitoring systems increasingly rely on MEMS sensors due to their compact size, low cost, and low power consumption.
View Article and Find Full Text PDFUltrasonics
January 2025
Department of Biomedical Engineering, The George Washington University, 800 22 nd St. NW Suite 5000, Washington, DC 20052, United States of America. Electronic address:
Objectives: In this study, we aim to investigate whether therapeutic ultrasound can modulate the release of melatonin from the pineal gland-either increasing or decreasing its levels-and to assess the safety of this technique. This research could address a significant clinical need by providing a noninvasive method to potentially regulate sleep and circadian rhythms through the targeted modulation of melatonin.
Methods: Rat pineal glands were placed in a well with a Krebs Ringer Buffer solution.
J Acoust Soc Am
January 2025
Escola Politécnica, University of São Paulo, São Paulo, 05508-030, Brazil.
Ultrasonic sensors based on backscattering principles have been developed for various applications involving arbitrary or random scatterer distributions. Although the theory of multiple scattering of waves is well-established, it has not been thoroughly explored in these applications. This work presents a feasible and simplified three-dimensional scattering model to predict the transient response generated by a set of rods positioned in the near field of a 1 MHz water-coupled ultrasonic transducer.
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