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Peripheral nerve stimulators have emerged as a crucial instrument in the realm of neurological disease, capable of modulating nerve activity through precisely targeted electrical stimulation to specific sites within the nervous system. Herein, a new wireless battery‐free peripheral nerve stimulation device for remote muscle activation is developed. The device with conch‐inspired bionic design can be wirelessly powered and controlled by a mobile phone playing audio via the piezoelectric effect. The device consists of two parts: a conch‐like signal‐intensifying piezoelectric resonator for converting acoustic wave into electrostimulation signal; and a pedestal with stimulation electrodes for transmitting the electrostimulation signal to a peripheral nerve. For remote nerve intervention, a programmed audio tone from one mobile phone can be tele‐transmitted from other phones according to the desired stimulation protocols. In‐vivo experiments in stimulating the sciatic nerve in mice showed that the device can activate muscles (e.g., 1 Hz 920 mV for 26 degree of leg movement), and the neuron‐muscle interaction has been confirmed by electromyogram (EMG). The wireless peripheral nerve stimulation conch achieves feasible remote muscle activation without batteries, and can extend the scope of self‐powered techniques for telemedicine and limb/trunk rehabilitation. [ABSTRACT FROM AUTHOR]

Softening of piezoelectric materials facilitates the development of flexible wearables and energy harvesting devices. However, as one of the most competitive candidates, piezoelectric ceramic-polymer composites inevitably exhibit reduced power-generation capability and weak mechanical strength due to the mismatch of strength and permittivity between the two phases inside. Herein a flexible, air-permeable, and high-performance piezoceramic textile composite with a mechanically reinforced hierarchical porous structure is introduced. Based on a template-assisted sol-gel method, a three-order hierarchical ceramic textile is constructed by intertwining submillimeter-scale multi-ply ceramic fibers that are further formed by twisting micrometer-scale one-ply ceramic fibrils. Theoretical analysis indicates that large mechanical stress can be easily induced in the multi-order hierarchical structure, which greatly benefits the electrical output. Fabricated samples generate an opencircuit voltage of 128 V, a short-circuit current of 120 μA, and an instantaneous power density of 0.75 mW cm-2, much higher than the previously reported works. The developed multi-order and 3D-interconnected piezoceramic textile shows satisfactory piezoelectricity (d33 of 190 pm V-1), air permeability (45.1 mm s-1), flexibility (Young's modulus of 0.35 GPa), and toughness (0.125 MJ m-3), collectively. The design strategy of obtaining balanced properties promotes the practicality of smart/functional materials in wearables and flexible electronics. [ABSTRACT FROM AUTHOR]

A miniaturized high temperature superconducting (HTS) ultra‐wideband (UWB) bandpass filter (BPF) is presented based on stub‐loaded multi‐mode resonator (SLMMR) in this letter. This SLMMR constructed by loading three sets of different open stubs on a stepped‐impedance resonator brings five resonant modes into the passband for UWB bandwidth and a pair of transmission zeros in the transition bands for high selectivity. The filter is finally designed and fabricated on a 0.5‐mm thick MgO substrate with double‐sided YBCO HTS films. At 77 K, the measured results show that the 3‐dB bandwidth covers 3.0 GHz‐12.0 GHz; the minimum insertion loss is 0.11 dB; the return loss is better than 15.75 dB; the out‐of‐band rejection is greater than 24.35 dB in the lower stopband, and the upper stopband with 20 dB attenuation level is extended to 16.77 GHz. [ABSTRACT FROM AUTHOR]