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Intraosseous ultrasound imaging is valuable for guiding pedicle screw placement in surgery. However, single-frequency ultrasound, whether low or high, often fails to provide both adequate imaging resolution and depth simultaneously. To address this limitation, we introduce a novel ultrafast multi-frequency ultrasound patch fusion imaging method for pedicle screw navigation. This approach combines […]

Wireless power transfer (WPT) with rectennas is important for IoT sensor applications. Miniature GHz voltage transformers are more attractive than a large-size charge pump to operate the rectifiers efficiently. In this study, GHz bulk acoustic wave (BAW) piezoelectric transformers based on c-axis zig-zag polarization-inverted ScAlN thin films are proposed. The capacitive impedance ( ${Z}_{C}$ ) […]

Doppler ultrasound is a noninvasive imaging technique that measures blood flow velocity and is commonly used in cardiac evaluation and vascular assessment. Compared to the conventional longitudinal view, cross-sectional Doppler is more robust to motion, making it more suitable for monitoring applications. In this article, an adaptive framework is presented to automatically monitor flow in the […]

This article reports a high-temperature acoustic emission (AE) sensor enabling couplant-free and waveguide-free attachments on structures operating up to $650~^{\circ }$ C. The microfabricated sensor is constructed using silicon carbide as the substrate and aluminum nitride (AlN) as the piezoelectric film. The piezoelectric coefficient ( ${d}_{{33}}$ ) of AlN is measured using piezoresponse […]

Piezoelectric ceramics tailored for high-power resonance applications are investigated, utilizing a composite structure comprising the ferroelectric phase (K, Na)NbO3 as a matrix integrated with the alkali titanoniobate dielectric phase KTiNbO5. Achieving a mechanical quality factor of 750, comparable to lead-based counterparts, highlights their suitability for demanding applications. Crucially, […]

Super-resolution ultrasound (SRUS) imaging through localizing and tracking microbubbles (MBs), also known as ultrasound localization microscopy (ULM), has achieved unprecedented resolution in deep tissue in vivo. In this review, we will focus on the key technical steps of ULM, including data acquisition and tissue clutter removal, motion correction, localization, tracking, and final image […]

Ultrasound localization microscopy (ULM) is a blood flow imaging technique that utilizes micrometer-sized microbubbles (MBs) as contrast agents to achieve high-resolution microvessel reconstruction through precise localization and tracking of MBs. The accuracy of MB localization is critical for producing high-quality images, which makes tissue clutter filtering an essential step in ULM. Recent […]

This article describes the study of loss mechanisms in an incredible high-performance surface acoustic wave (IHP SAW) resonator on the 42°YX-LiTaO3/SiO2/Si structure. The full 3-D finite element method (FEM) is applied with the assistance of the hierarchical cascading technique (HCT). Excellent agreement is obtained between calculation and measurement not only for the effective electromechanical […]

Plane wave imaging (PWI) is pivotal in medical ultrasound (US), prized for its ultrafast capabilities essential for real-time physiological monitoring. Traditionally, enhancing image quality in PWI has necessitated an increase in the number of plane waves (PWs), unfortunately compromising its hallmark high frame rates. To fully leverage the frame rate advantage of PWI, existing […]