Bin Yang

To enhance low-frequency detection sensitivity and achieve omnidirectionality in underwater acoustic sensors, this paper reports a hexagonal array piezoelectric MEMS acoustic sensor (HAAS). The HAAS comprises six identical triangular cantilever beams symmetrically arranged in a regular hexagon. This array configuration enables signal superposition to boost sensitivity, while the multi-degree-of-freedom vibrating membrane promotes omnidirectionality in underwater acoustic detection. The distinctive hexagonal array structure imparts exceptionally high sensitivity in the frequency range of 630Hz to 1.6kHz (−161.2 dB at fixed 1.6kHz,ref.1 V/ $\upmu $ Pa) and superior omnidirectional directivity, with nonuniformities of ±0.5 dB in the horizontal plane and ±0.3 dB in the vertical plane at 2 kHz. Experimental results demonstrate the substantial potential of the HAAS for applications in underwater biological activity monitoring, communication, and resource exploration.[2025-0191]

Inspired by marine mammals’ exceptional low-frequency hearing, we present a biomimetic cochlea-like scandium-doped aluminum nitride MEMS hydrophone (BCMH) for miniaturized, high-fidelity underwater acoustic sensing. The device employs a compact spiral stress-sensing architecture, achieving a flat receiving sensitivity of $- 167.7~\pm ~1.1$ dB (re V/ $\mu $ Pa), excellent omnidirectivity ±0.5 dB vertical and ±0.9 dB horizontal, with lower than the self-noise base of the first-order sea state. Enabled by bioinspired cochlear geometry and advanced piezoelectric materials, it offers a practical, high-performance solution for low-frequency seismic monitoring and next-generation underwater acoustic sensing, surpassing conventional hydrophone technologies.

Neural probes targeting single neurons are instrumental in overcoming the ambiguity associated with population-averaged signals and the attenuation of extracellular signals to reveal the fundamental units of neural coding. However, current neural probes are limited by resolution, structural design, and micro/nanotechnology, making it challenging to penetrate single neurons in vivo to directly record various neural signals. Here, we report a multilayer carbon-structured nanoprobe (MLCNP) for intracellular electrophysiological and chemical recordings in vivo. The sensing layers, composed of graphene and feather-shaped carbon nanowires (FCNW), and the protective layer of nanodiamond are prepared via microwave plasma chemical vapor deposition. The controlled exposure of nanotips, roughening of FCNW sensing layers, and adsorption of Pt nanoparticles on their surface are achieved through microplasma jet branch etching (MPJBE). The multilayer carbon structures and the MPJBE treatment significantly enhance the cathodic charge, peak cathodic current and sensitivity to dissolved O₂ of nanoprobes. The MLCNP with a tip diameter of approximately 70 nm and an exposed sensing area length of about 900 nm, demonstrates good cytocompatibility, minimal invasive damage, and selective O₂-sensing capabilities. Finally, intracellular electrophysiological signals and variations in O₂ concentration, along with other potential biochemical signals, are successfully recorded in vivo, and the effects of pain stimulation on electrophysiological spikes were analyzed. The developed nanoprobe based on the new materials and processes and its successful acquisition of electrical and biochemical signals at the single-neuron level in vivo, hold profound significance for a deeper understanding of the intrinsic mechanisms of the nervous system.

The ultrasonic cavitation effect plays a critical role in non‐invasive medical treatment. To develop a flexible ultrasonic cavitation patch, it is necessary to enhance the emission intensity of the transducer to reach the threshold sound pressure at low operating voltages, while simultaneously minimizing potential risks to surrounding tissues. This paper presents a piezoelectric ultrasonic micro‐patch with low operating voltage and high safety. The device is fabricated using microfabrication techniques to obtain thin piezoelectric ceramics, which are then embedded in an elastic base layer to ensure optimal adhesion. A ring‐island structure is further designed to integrate both ultrasonic emission and reception functions within a single patch. Sound field simulation and experimental results indicate that, under a driving voltage of 25 Vpp, the emitted ultrasonic intensity reaches 90 kPa, enabling the observation of bubble generation and oscillation in liquids. The mechanical index is only 0.11. To enhance safety, an ultrasonic switch circuit was designed to ensure the temperature remains below 38°C and the spatial‐peak temporal‐average intensity is less than 100 mW/cm ² . This study contributes significantly to the advancement of wearable ultrasound therapy.

Conventionally designed edge-bound type piezoelectric Micro Electro Mechanical Systems (MEMS) speakers with Si supporting layer still suffer from the problem of low sound pressure level (SPL) and high total harmonic distortion (THD). In this paper, we demonstrate a center-bound type piezoelectric MEMS speaker based on flexible supporting layer, which meets the minimum SPL requirement for human hearing, and achieves a lower THD over a wider continuous frequency band compared with the reported state-of-the-art works, and demonstrates good reliability and durability. Test results in an acoustics test adaptor show that at a driving voltage of 1 V ${}_{\mathbf {rms}}$ , greater than 52dB SPLs are obtained in the human audible range of 20Hz-20kHz, basically meeting the minimum auditory requirements for human beings. The applicable working frequency range for THD of this device spans the medium and high frequency band of 500 Hz-20 kHz. Compared with state-of-the-art reported works, it achieves a THD of $\le 5$ % over a significantly wider continuous frequency range. Moreover, this speaker produces no abnormal sound, shows no fracture after dropping from a height of 5meters, and maintain at least 90% of the SPLs after playing music continuously for 100 hours. The proposed center-bound type piezoelectric MEMS speaker with flexible supporting layer is expected to drive its own development and practical application by offering new perspectives and design concepts to researchers and enterprises. [2025-0116]

MEMS vector hydrophones are poised to become the core devices of miniaturized underwater acoustic sensing. However, existing MEMS vector hydrophones suffer from low sensitivity and shallow concave point depth, which hinders long-range detection. In this work, we present an axisymmetric bionic seal whisker–type piezoelectric MEMS vector hydrophone (ASWVH) that leverages bioinspired geometries and stress-concentration regions to amplify piezoelectric output, yielding enhanced directivity and high sensitivity. The optimal microstructure dimensions for ASWVH were determined using COMSOL 5.6 simulations. The biomimetic seal whisker structure not only ensures an operational frequency bandwidth of 20–2000 Hz but also expands the effective acoustic reception area, thereby further enhancing sensitivity. The unique wavy bionic sealing whisker shape provides high sensitivity, and the measured X-axis and Y-axis sensitivities are -171.7 dB and -173.2 dB@2 kHz (re. 1 V/μPa), respectively. Moreover, the device exhibits an exceptional “8”-shaped directivity pattern with concave point depth exceeding 40 dB in both channels, rendering it well-suited for high-precision passive underwater detection.