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Herein, a high‐quality Al0.56Sc0.44N (112¯0)$\left(\right. 11 \overset{\cdot}{2} 0 \left.\right)$ piezoelectric thin‐film‐based surface acoustic wave (SAW) resonator is developed. The Al0.56Sc0.44N is deposited on r‐plane Al2O3(11¯02)$\left(\right. 1 \overset{\cdot}{1} 02 \left.\right)$ substrate by reactive magnetron sputtering. X‐ray diffraction (XRD) spectroscopy shows that the grown Al0.56Sc0.44N films are single‐phased and a‐plane oriented. The full width at half maximum of the XRD rocking curve is only 0.4°, which is smaller than most of the reported values. The effects of normalized thickness of the piezoelectric layer, electrode materials, and thickness on acoustic properties of the SAW resonators are investigated through the 3D finite‐element method equipped with the hierarchical cascading technique. A monotonically decreasing resonant frequency can be obtained with the mass loading of both the electrode metals. For the devices with a Pt electrode, it is observed that the electromechanical coupling coefficient (keff2$k_{\text{eff}}^{2}$) exhibits a nonlinear characteristic of first increasing and then decreasing with the increase of electrode thickness. SAW resonators with a nonpolar a‐plane Al0.56Sc0.44N thin films are fabricated, showing an exceptionally high keff2$k_{\text{eff}}^{2}$ of 4.6%. This result demonstrates a significant potential of AlScN films with the a‐plane orientation in radio frequency application. [ABSTRACT FROM AUTHOR]

Polyvinylidene fluoride (PVDF) and its copolymers present extensive application prospects, especially in the field of wearable electronics. However, utilizing nanofillers for enhanced β‐phase and piezoelectric properties faces challenges like noncontinuous interfaces, poor compatibility between nanofillers and PVDF matrix, and the requirement of high‐voltage polarization, hindering extensive domain alignment on a large scale. Herein, a method is proposed to synthesize high‐performance PVDF composites by introducing hydroxylated barium titanate (H@BTO) nanoparticles and a directional freeze‐drying method to enhance β‐phase content and piezoelectric properties without polarization. Molecular dynamics simulations reveal robust binding interactions between Ba and F atoms along with OH surface terminations on H@BTO, facilitating hydrogen bonding within the PVDF matrix, resulting in dipole alignment and increased spontaneous polarization. The composite film achieves an 86.69% β phase content and a piezoelectric coefficient of ≈14.49 pm V−1 without electric polarization. The freeze‐drying PVDF‐H@BTO composite film paired with a PA6 membrane is used to fabricate triboelectric nanogenerator, demonstrating a current density of ≈107.5 mA m−2 and an output voltage of ≈832 V. Results demonstrate that the utilization of strong binding interactions between various atoms, the hydroxyl anchoring effect, and directional freeze‐drying method as a strategy holds promising prospects for synthesizing high‐performance piezoelectric composites. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerator (TENG) is a promising technology, which can convert biokinetic energy into electricity and be utilized as self‐powered sensors and power sources for wearable electronics. The existing designs of conventional TENGs require complex fabrication processes and device structures, and they need to be attached on human body for wearable application, which is uncomfortable and may lead to malfunction under intense body moment. Here, a direct current TENG is proposed by utilizing natural human body, basketball, shoes, and ground floor. A unidirectional peak voltage and current output up to 700 V and 23 µA can be generated when a player plays a basketball, which can lighten up an array of 240 LEDs, and charge a 100 µF capacitor to 3.2 V in 1 min. The output of TENG is utilized to identify different movements of a basketball player using machine learning algorithm with an accuracy up to 96.7%. Moreover, the human body enabled direct current TENG (HBDC‐TENG) is used as a self‐powered sensor and an energy harvester for a wireless sensing system, which can collect human motion and environmental information, and transmit them wirelessly. The HBDC‐TENG has a great significance for self‐powered wearable electronics, providing a viable solution for human motion status and ambient environment monitoring. [ABSTRACT FROM AUTHOR]

This paper demonstrates a 3.4 GHz micro‐acoustic filter with excellent in‐band insertion loss, rectangle coefficient, and out‐of‐band rejection. The proposed filter was based on a novel topology by integrating the bulk acoustic wave (BAW) resonators with an on‐chip clamping inductor, the introduction of the lumped components is beneficial for improving the filters' stopband rejection while having minimal influence on the rectangle coefficient and in‐band insertion loss. Al0.8Sc0.2N material was selected as the piezoelectric film of the BAW device and the inductor was fabricated on the same wafer with BAW devices. The manufactured filter has a minimum in‐band insertion loss of ~ 1.5 dB, a 3 dB bandwidth of about 170 MHz, and a stopband rejection of nearly ‐30 dB. The experimental results verify the design and show great applications for 5G communication and beyond. [ABSTRACT FROM AUTHOR]

Phononic crystals (PnCs) exhibit acoustic properties that are not usually found in natural materials, which leads to the possibility of new devices for the complex manipulation of acoustic waves. In this article, a micron‐scale phononic waveguide constructed by line defects in PnCs to achieve on‐chip, tightly confined guiding, bending, and splitting of surface acoustic waves (SAWs) is reported. The PnC is made of a square lattice of periodic nickel pillars on a piezoelectric substrate. The PnC lattice constant, pillar diameter, and pillar height are set to 10, 7.5, and 3.2 µm, respectively, leading to a complete bandgap centered at 195 MHz. Interdigitated transducers are monolithically integrated on the same substrate for SAW excitation. The guiding, bending, and splitting of SAWs in the phononic waveguide are experimentally observed through measurement of the out‐of‐plane displacement fields using a scanning optical interferometer. The combination of destructive interference due to the Bragg bandgap and the interaction of the propagating wave with the pillars around the channel results in a tight confinement of the displacement field. The proposed phononic waveguides demonstrate the feasibility of precise local manipulation of SAW that is essential for emerging frontier applications, notably for phonon‐based classical and quantum information processing. [ABSTRACT FROM AUTHOR]

Active electrocorticogram (ECoG) electrodes can amplify weak electrophysiological signals and improve anti‐interference ability; however, traditional active electrodes are opaque and cannot realize photoelectric collaborative observation. In this study, an active and fully transparent ECoG array based on zinc oxide thin‐film transistors (ZnO TFTs) is developed as a local neural signal amplifier for electrophysiological monitoring. The transparency of the proposed ECoG array is up to 85%, which is superior to that of the previously reported active electrode arrays. Various electrical characterizations have demonstrated its ability to record electrophysiological signals with a higher signal‐to‐noise ratio of 19.9 dB compared to the Au grid (13.2 dB). The high transparency of the ZnO‐TFT electrode array allows the concurrent collection of high‐quality electrophysiological signals (32.2 dB) under direct optical stimulation of the optogenetic mice brain. The ECoG array can also work under 7‐Tesla magnetic resonance imaging to record local brain signals without affecting brain tissue imaging. As the most transparent active ECoG array to date, it provides a powerful multimodal tool for brain observation, including recording brain activity under synchronized optical modulation and 7‐Tesla magnetic resonance imaging. [ABSTRACT FROM AUTHOR]

Objective: To tackle the challengeable dilemma of delayed femoral fracture, a technique of fixator‐assisted closed reduction and intramedullary nailing at one stage was introduced herein and its clinical results were investigated. Methods: A retrospective study was conducted on delayed femoral shaft fracture between February 2008 and January 2017. The multiple injured patients aged from 18 to 60 years with delayed femoral fracture was included. All patients were treated by one‐stage internal fixation technique and followed up for more than 1 year. Outcome measures including the operation time, intraoperative blood loss and limb alignment, healing time of fracture, visual analog scale (VAS), and range of knee motion were recorded and evaluated. Results: A total of 13 patients (16 sides) with a mean injury severity score (ISS) of 32.77 ± 9.98 (range, 19 to 52) participated in the investigation. The median length of time‐after‐fracture was 38 days (range, 21 to 110 days). The average shortening distance of the fracture ends was 35.48 ± 19.24 mm (range, 10.00 to 79.00 mm). The average surgery time was 192.19 ± 29.38 min for unilateral femoral fracture, with blood loss of 587.50 ± 232.02 ml. The postoperative discrepancy of lower limb was 3.87 ± 2.52 mm. No patient had vascular and neurologic complications due to the lengthening. All fractures healed successfully with a mean time of 2.98 ± 0.57 months. The mean VAS and maximal knee flexion were 1.63 ± 1.09 and 131.25° ± 5.32° at final follow‐up, respectively. Conclusions: Our findings indicated that fixator‐assisted closed reduction and intramedullary nailing at one stage is an effective treatment for delayed femoral fracture with satisfactory functional recovery. [ABSTRACT FROM AUTHOR]

Stretchable electronics‐based surface electromyography (sEMG) evaluation devices are expected to play a big role in clinical diagnosis. However, the stability and quality of the signals collected by existing stretchable electronics are too poor, especially when muscle movement is involved, making them inappropriate for high standard clinical diagnosis. Here, a physiology‐based design method for stretchable electronics and a novel airbag‐type stretchable electrode array (ASEA) device for assessment of the complex female pelvic floor muscle (PFM) is proposed. Clinical trials show that the ASEA device is able to provide stable contact interface and multi‐channel accurate data acquisition. The stability and quality of the sEMG signal are much better than those obtained by the existing stretchable electronics‐based PFM electrode devices. Furthermore, a muscle‐unit evaluation method (MUEM) to assess the PFM complex state is proposed, especially its cross‐interaction between muscles. Clinical trials show that MUEM can accurately and comprehensively assess PFM state and the correlations between main muscles, which unveils the mechanisms of some special muscle states that are not possible using traditional methods. This proof of concept research holds the promise for the development of new diagnostic strategies for muscle pathological research, and has the potential for clinical application and general implication. [ABSTRACT FROM AUTHOR]

In this paper, new strategies are proposed to design high‐performance organic–inorganic hybrid perovskite (PVK)‐based triboelectric nanogenerators (TENGs) via both chemical composition modulation and electric field‐induced ion migration in the films. Both composition variation and ion migration under electric field are found to change the type of conductivity of the perovskite films, then modify their surface potentials and electron affinities. These are utilized to fabricate PVK‐based TENGs in pairs with poly‐tetrafluoroethylene (PTFE) or nylon films, respectively. Results show that PVK films are able to work as either a positive or a negative tribo‐material depending on the tribo‐material pair used; the optimal performances are obtained for PTFE/PVK TENGs using a PVK film with a MAI/PbI2 ratio of 2 and forward polarization, and for nylon/PVK TENGs using a PVK film with a MAI/PbI2 ratio of 0.4 and reverse polarization, respectively. The maximum output voltage and peak power density of PTFE/PVK TENGs are about 979 V and 24 W m−2, 2.5 and 6.5 times higher than those of TENGs with nonoptimal composition ratio or that are poorly polarized. This work provides a new material design method for high‐performance TENGs and a novel polarization strategy for TENG performance enhancement. [ABSTRACT FROM AUTHOR]

As the most frequent wound complication, infection has become a major clinical challenge in wound management. To overcome the "Black Box" status of the wound‐healing process, next‐generation wound dressings with the abilities of real‐time monitoring, diagnosis during early stages, and on‐demand therapy has attracted considerable attention. Here, by combining the emerging development of bioelectronics, a smart flexible electronics‐integrated wound dressing with a double‐layer structure, the upper layer of which is polydimethylsiloxane‐encapsulated flexible electronics integrated with a temperature sensor and ultraviolet (UV) light‐emitting diodes, and the lower layer of which is a UV‐responsive antibacterial hydrogel, is designed. This dressing is expected to provide early infection diagnosis via real‐time wound‐temperature monitoring by the integrated sensor and on‐demand infection treatment by the release of antibiotics from the hydrogel by in situ UV irradiation. The integrated system possesses good flexibility, excellent compatibility, and high monitoring sensitivity and durability. Animal experiment results demonstrate that the integrated system is capable of monitoring wound status in real time, detecting bacterial infection and providing effective treatment on the basis of need. This proof‐of‐concept research holds great promise in developing new strategies to significantly improve wound management and other pathological diagnoses and treatments. [ABSTRACT FROM AUTHOR]

A bidirectional punch-through transient voltage suppressor based on a five-layer N++P+PP+N++ structure is developed. By realizing the device using a 12-finger layout, transmission line pulse measurements indicate that the device has met the IEC61000-4-2 standard with electrostatic discharge robustness of ±8 kV and has an ultralow capacitance value of less than 0.17 pF. Under 3.3 V forward or reverse bias, the device exhibits a leakage current of less than 2 nA. These excellent figures suggest that the developed structure is well suited for actual system-level protection applications. © 2016 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

This Letter reports a high‐performance film bulk acoustic resonator (FBAR) that can be applied in 5G wireless communication. The FBAR has a back‐etched free‐standing structure using an ultra‐thin single‐crystalline lithium niobate (LiNbO3) as the piezoelectric film. The thin LiNbO3 was obtained by the smart cut method and FBARs were fabricated by a standard MEMS process. Owing to the superior bulk‐like properties of the single‐crystal thin film, the fabricated FBARs have a resonant frequency of 5.0 GHz, a quality factor above 1800 and an electromechanical coupling coefficient of 2.66%, demonstrating a promising potential of FBAR filters in 5G and future 6G applications. [ABSTRACT FROM AUTHOR]

A modified lateral-diffusion metal-oxide-semiconductor (MLDMOS) device with improved electrostatic discharge (ESD) protection performance is proposed for high-voltage ESD protection. In comparison with the traditional LDMOS and the LDMOS with an embedded silicon-controlled rectifier (LDMOS-SCR), the proposed device has better ESD robustness and higher holding voltage. By optimizing key parameters, such as the spacing between the drain and the poly gate, the effective channel length, and the number of fingers, the MLDMOS can achieve a maximum failure current over 80 mA/µm, which is larger than that of LDMOS-SCR. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [ABSTRACT FROM AUTHOR]

Triboelectric nanogenerators (TENGs) have received significant attention in recent years due to their renewable and sustainable properties. They convert mechanical energy into electric energy through contact and separation of two dissimilar materials. Many methods have been developed to improve the performance of TENGs, but little attention has been paid to use nanoparticles such as BaTiO3 (BTO) with high dielectric constant for enhancing the performance. This paper reports the achievement of significant performance enhancement of poly(vinylidene fluoride) (PVDF)/polyamide‐6 (PA6) TENGs by incorporating BTO nanoparticles into the PVDF film. The PVDF‐BTO/PA6 TENG with 10 wt% BTO nanoparticles shows the best results with a peak voltage and charge density up to 900 V and 34.4 μC m−2 at contact frequency of 5 Hz when the contact force and the spacer distance are 180 N and 100 mm, which are much higher than 384 V and 26.4 μC m−2 of the PVDF/PA6 TENG without incorporating BTO nanoparticles. Further increase in the BTO concentration deteriorates the output performance of the TENGs. Detailed investigations on the piezo‐response and permittivity of the PVDF‐BTO films show that the increased piezoelectric constant and permittivity are responsible for the significantly enhanced performance of the TENGs. A mathematical model has been developed to describe the output voltages of the TENG as a function of thickness of the PVDF‐BTO film. Incorporation of BaTiO3 (BTO) nanoparticles in PVDF enhances the performance of triboelectric nanogenerators (TENGs). The PVDF‐BTO/PA6 TENG with 10 wt% BTO shows the best results with a peak voltage and charge density up to 900 V and 34.4 μC m−2, respectively, much higher than 384 V and 26.4 μC m−2 of the PVDF‐PA6 TENG without BTO nanoparticles. [ABSTRACT FROM AUTHOR]

Graphene field‐effect transistors (GFETs) are characterised for the first time under electrostatic discharge stresses. The GFETs are measured from the transmission line pulsing (TLP) tester and very fast TLP (VFTLP) tester. The turn‐on behaviour influenced by back gate voltage is investigated. The I–V curve of the GFETs shows no characteristic of snapback from TLP or VFTLP measurement. [ABSTRACT FROM AUTHOR]