Search

The development of flexible and stretchable devices is crucial for realizing future electronics. In particular, for dielectric layer, conventional inorganic materials are limited by their brittle nature, while organic materials suffer from a low dielectric constant. Here, a novel intrinsically photopatternable high‐k Parylene‐based thin film (Parylene‐OH) is fabricated via a chemical vapor deposition process based on the Gorham method, which provides pin‐hole free, conformal polymeric film on any type of surface. Parylene‐OH can be photo‐patterned by UV crosslinking without further lithography processes and dielectric constant of Parylene‐OH increases from 6.05 to 7.53 after crosslinking, without degrading other parameters, making it comparable to conventional high‐k dielectric, Al2O3. Flexible In─Ga─Zn─O (IGZO) thin‐film transistors (TFTs) with patterned dielectric layers can withstand higher strain owing to the localized pattern of each unit. A CMOS inverter integrated with n‐type IGZO and p‐type Te TFTs is successfully fabricated. Parylene‐OH can be used in the future of state‐of‐the‐art flexible electronic devices. [ABSTRACT FROM AUTHOR]

In this work, the development of a flexible Double‐Gate (DG) organic thin film transistor (DG‐OTFT), and its employment is reported for the realization of multimodal tactile sensors. Due to the self‐encapsulation of the stacked DG architecture, highly stable organic transistors are obtained that show almost negligible degradation after 6 months. Moreover, such configuration is also very useful for the development of sensing devices. In the case, one of the two gates is used to bias and set the working point of the devices, whereas the second one is connected to a polyvinylidene fluoride(PVDF)‐capacitor, a pyro/piezoelectric material. It is demonstrated that the charge displacement induced by the PVDF capacitor due to an applied external pressure or due to a temperature variation led to a reproducible variation of the device's output current. Using this approach high‐performing multimodal tactile sensors are obtained with sensitivity to up to 241 nA N−1 and 442 nA °C−1 respectively. [ABSTRACT FROM AUTHOR]

One SMEG can generate a maximum V oc and I sc of 0.57 V and 66 μA when a small amount of LiCl is dropped on one side at ambient humidity. V oc and I sc reach up to 3.55V and 204 μA when six SMEGs are connected in series or in parallel. The series connection of six SMEGs successfully lit an LED and a calculator, respectively. [Display omitted] In response to the energy crisis caused by the exhaustion of fossil energy sources, as well as to combat global warming and achieve carbon neutrality, a sandwiched-structure fabric-based moisture-enabled electricity generator (SMEG) has been developed. Cotton fabric coated with MWCNT and PEDOT: PSS solution is used as the upper and bottom electrodes, while the acid-treated cotton fabric with coating PVA and HCl hydrogel electrolyte serves as the middle layer. A single SMEG can generate a maximum open-circuit voltage (V oc) of 0.44 V and a maximum short-circuit current (I sc) of 30 μA. When a drop of LiCl is dripped on one side of SMEGs, the maximum V oc and I sc increases to 0.57 V and 66 μA, respectively. The decline in output performance slows down when LiCl is applied. The V oc increases almost linearly in series and reaches 3.55 V when six SMEGs are connected, while the I sc increases linearly in parallel and reaches 204 μA when six SMEGs are connected. The maximum power density of a single SMEG yields 0.29 μW/cm2 with an external resistance of 1 kΩ. The series connection of six SMEGs successfully lit an LED and a calculator under ambient humidity conditions, demonstrating their potential application in small electronics. [ABSTRACT FROM AUTHOR]

Flexible perovskite light‐emitting diodes (f‐PeLEDs) have attracted increasing interest to realize true‐color, low‐cost, and light‐weight wearable optoelectronic and flexible display applications. However, their external quantum efficiency (EQE) and mechanical stability lag far behind because of the inherent surface and brittle issues of polycrystalline perovskite films. In this work, a multi‐functional polymeric‐termination surface of perovskite film is constructed for achieving efficient and mechanically stable f‐PeLEDs. It takes the roles to not only reduce defects through equipping coordination groups to improve emission properties, but also optimize film morphology and eliminate pinholes to solve the long‐standing issue of leakage current. Meanwhile, the polymeric‐termination surface with anchoring points and polymeric soft chains on perovskites demonstrates synergetic effects beyond the corresponding functional group‐only or polymer‐only strategies in reducing the Young's modulus and improving the mechanical flexibility. Ultimately, the record EQE of 22.1% and significantly enhanced mechanical stability of maintaining 82% of the initial performance after 2000 bending cycles with radius of 5 mm are achieved in pure‐green f‐PeLEDs. The work paves the way for the development of high‐performance flexible optoelectronic devices. [ABSTRACT FROM AUTHOR]

Bimode temperature‐pressure sensors hold significant promise in personal health monitoring, wearables and robotic signal detection. Traditional bimode sensors typically combine two independent sensors, leading to fabrication complexity. This study develops a bimode temperature‐pressure sensor by using a facile electrodeposition method to create sandwiched BiSbTe/Carbon Paper/BiSbTe thin films and stacking them to a vertical structure. It demonstrates high sensitivity for temperature sensing, capable of detecting temperature difference as low as 1 K, and a rapid response time of 0.92 s due to a vertical structure. Utilizing its thermoelectric mechanism, the sensor achieves self‐powered sensing for finger touch and respiration states. Furthermore, its island‐like contact surface ensures high sensitivity with an extremely fast response time of 0.17 s, by rapidly changing contact resistance under pressure, allowing it to detect various human behaviors, including body movements and micro‐expressions. Beyond its sensing capabilities, the film excels in flexibility, electromagnetic interference shielding, and stability, presenting significant potential for integration into self‐powered electronic skin systems for health monitoring, wearables, artificial intelligence, and other electronic skin applications. [ABSTRACT FROM AUTHOR]

There is a pressing need for flexible integrated systems owing to the swift progress of flexible electronics. Apart from flexibility, flexible supercapacitor (FSC) integrated systems exhibit certain characteristics like rapid charge–discharge rates, high power density, and excellent cycling stability, which makes them a promising candidate to serve as a vital component in flexible electronics. In this context, an in‐depth overview of recent progress in FSC‐integrated systems, including their design of structure, materials, fabrication techniques, and applications, is offered. On the basis of the current progress, the existing challenges and future prospects are also outlined and discussed. [ABSTRACT FROM AUTHOR]

The hunt for sustainable and efficient energy harvesting and storage devices has driven significant interest in triboelectric nanogenerators (TENGs) as potential alternatives to traditional batteries for powering electronic devices. However, the development of biodegradable TENGs remains a formidable challenge. This study presents the preparation of a tribopositive material entirely composed of biodegradable poly(butylene adipate-co-terephthalate) (PBAT) polymer enhanced with CoFe2O4 (CF) nanoparticles. The CF nanoparticles, synthesized via the combustion method, were incorporated into the PBAT matrix through solvent casting to form films with varied filler content (0.2, 0.4, 0.6, 0.8, and 1 g). The CF nanoparticles structural, surface, and electrical properties were characterized using XRD and FTIR spectroscopy. At the same time, the morphology of the nanomaterials and their composites was analyzed by scanning electron microscopy. Specifically, the 0.8 g PBAT-CF TENG demonstrated superior performance, achieving an output voltage of 45.45 V and a current of 4.5 µA. Subsequent electrical studies, including charging commercial capacitors (1.0 to 47 μF) and powering LEDs and calculators, underscored the device's efficiency. The PBAT-CF TENG also effectively generated voltage and current signals from physical activities like walking and jumping. This innovative approach highlights the potential for biodegradable, high-performing, self-powered flexible electronics, and wearable devices, paving the way for sustainable technological advancements. [ABSTRACT FROM AUTHOR]

Copyright of Advanced Textile Technology is the property of Zhejiang Sci-Tech University Magazines and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In recent years, perovskite solar cells (PSCs) have emerged as a focal point for numerous researchers due to their excellent photoelectric performance. In comparison to their single‐junction devices, double‐junction cells have exhibited the potential for superior power conversion efficiency (PCE). Copper indium gallium selenide (CIGS) solar cells, a well‐established photovoltaic technology, can be used as a viable bottom cell candidate for double‐junction tandem solar cells (TSCs). Recently, the PCE of the most advanced 4T perovskite/CIGS TSCs reached 29.9%, while the highest PCE of 2T perovskite/CIGS TSC is 24.2%, which develops relatively slowly. In contrast to the leading perovskite/silicon (Si) TSCs in terms of PCE (PCE2T = 33.9%, PCE4T = 30.35%), perovskite/CIGS TSCs exhibit distinctive advantages such as adjustable bandgap, high absorption coefficient, radiation resistance, and can be prepared on flexible substrates. Building upon these advantages, the optimization process in four‐terminal and two‐terminal perovskite/CIGS TSCs is elucidated, the key technologies and challenges in material, structure, and photoelectric performance of the tandem cells are summarized, and a prospective analysis of their future overall development in this review is provided. Furthermore, it is hoped to give readers a comprehensive understanding of perovskite/CIGS TSCs. [ABSTRACT FROM AUTHOR]

Air quality is deteriorating due to continuing urbanization and industrialization. In particular, nitrogen dioxide (NO2) is a biologically and environmentally hazardous byproduct from fuel combustion that is ubiquitous in urban life. To address this issue, we report a high‐performance flexible indium phosphide nanomembrane NO2 sensor for real‐time air quality monitoring. An ultralow limit of detection of ~200 ppt and a fast response have been achieved with this device by optimizing the film thickness and doping concentration during indium phosphide epitaxy. By varying the film thickness, a dynamic range of values for NO2 detection from parts per trillion (ppt) to parts per million (ppm) level have also been demonstrated under low bias voltage and at room temperature without additional light activation. Flexibility measurements show an adequately stable response after repeated bending. On‐site testing of the sensor in a residential kitchen shows that NO2 concentration from the gas stove emission could exceed the NO2 Time Weighted Average limit, i.e., 200 ppb, highlighting the significance of real‐time monitoring. Critically, the indium phosphide nanomembrane sensor element cost is estimated at <0.1 US$ due to the miniatured size, nanoscale thickness, and ease of fabrication. With these superior performance characteristics, low cost, and real‐world applicability, our indium phosphide nanomembrane sensors offer a promising solution for a variety of air quality monitoring applications. [ABSTRACT FROM AUTHOR]

Researchers have created a modern infrared (IR) sensor that is both super-sensitive and highly flexible. This remarkable device possesses impressive properties of exceptional sensitivity (24,000%), high responsiveness (1.25 A/W), and fast response time (3 ms). This innovation stands out for its unique construction: an ultrathin layer of lead sulfide (PbS) deposited on a standard Whatman filter paper. This design achieves a photo-current 32 times greater than previous record-holding PbS thin films. The key advantage is its unmatched flexibility. This sensor can bend and flex without breaking, maintaining its IR detection capabilities even after enduring extreme bending cycles. This breakthrough paves the way for a new era of wearable IR photo sensors, flexible electronics, and medical applications. [ABSTRACT FROM AUTHOR]

The conversion of ambient mechanical vibrations into electricity using piezoelectric nanogenerators (PENGs) has garnered significant attention from researchers over the past few years, in light of its potential in wearable applications. The high flexibility and significant ferroelectricity of poly(vinylidene fluoride) (PVDF) make them the most promising candidates for PENG applications among polymer piezoelectric materials. In the present work, NiO nanoparticles were incorporated in different ratios into a PVDF matrix, and their potential for use in piezoelectric nanogenerators was investigated. The PVDF/NiO (5 wt.%) nanocomposite PENG exhibited the highest electrical output, with a 2.8-fold increase in open-circuit voltage and short-circuit current observed as compared to a bare PVDF-based PENG. However, a further increase in the compositional ratio of NiO led to a decrease in PENG output. The improved piezoelectricity in the PVDF/NiO (5 wt.%) nanocomposite is attributed to the enhanced polar phases and improved ferroelectricity of PVDF. Further confirmation of the improved piezoresponse was explored by measurement of the piezoelectric coefficient (d33) and dielectric study of the nanocomposites. The PENG electrical output was further simulated using the finite elemental method in COMSOL Multiphysics 5.5. The simulated results matched well with the experimental output, which confirmed the improved electrical performance of the PVDF/NiO nanocomposite-based PENGs. The enhanced performance of the nanocomposite PVDF film is attributed to the higher β phase in the PVDF. The efficiency of the PENG devices in motion-sensing applications was also explored. Different output voltage signals corresponding to different movements of the nanocomposite-based PENGs make the device compatible with sensor applications. [ABSTRACT FROM AUTHOR]

This research article presents a monopole antenna-based sensor for detecting cow pregnancy through urine analysis. The proposed flexible antenna sensor is printed on denim fabric with a permittivity of 1.7 and a loss tangent of 0.002. The flexible antenna resonates at 2.4 GHz and the gain of the proposed antenna sensor is 2.016 dBi, with a corresponding efficiency of 96.8%. The antenna's dimensions are 30 × 44 × 1 mm3. The substrate region behind the inner area of the radiator ring acts as a sensing area. This substrate can absorb liquids through the sensing area, causing the dielectric properties of the substrate to change according to the dielectric constant of the fluid under test. Urea concentration in pregnant cow urine is 11.06 mg/dL and 1.39 mg/dL in non-pregnant cow urine. The proposed antenna sensor uses microwave signals to detect pregnancy in cows. The deviation in resonance frequency and quality factor are used as key parameters for detecting cow pregnancy. [ABSTRACT FROM AUTHOR]

With the advent of the internet era, wearable electronic devices and flexible electronic technology are rapidly emerging, and new resistive random access memory (RRAM) based on flexible substrates have thus gained extensive attention. Here, the flexible Bi 0·95 Er 0·05 FeO 3 /ZnO/La 0·66 Sr 0·34 MnO 3 (BEFO/ZnO/LSMO) heterostructure is prepared on Mica substrate using the sol-gel method. The high resistance state (HRS) to low resistance state (LRS) ratio consistently surpasses 102 under the flat and the 15 mm bending radius state. There is no significant change in the resistive switching (RS) behavior after 30 I–V curve cycles and 103 write/erase operations on the BEFO/ZnO/LSMO heterostructure, which reflects excellent stability. In addition, the device still works properly at 175 °C for dynamic conversion between HRS and LRS. The observed RS behavior in the BEFO/ZnO/LSMO heterostructure is attributed to ion migration and alterations in the potential barrier height at the interfaces. These results suggest that the BEFO/ZnO/LSMO heterostructure based on a flexible Mica substrate plays a crucial role in the development of next-generation portable and flexible electronic systems due to its excellent flexibility and thermal stability. [ABSTRACT FROM AUTHOR]

The growing demand for wearable healthcare devices has led to an urgent need for cost-effective, wireless and portable breath monitoring systems. However, it is essential to explore novel nanomaterials that combine state-of-the-art flexible sensors with high performance and sensing capabilities along with scalability and industrially acceptable processing. In this study, we demonstrate a highly efficient NiS2-based flexible capacitive sensor fabricated via a solution-processible route using a novel single-source precursor [Ni{S2P(OPr)2}2]. The developed sensor could precisely detect the human respiration rate and exhibit rapid responsiveness, exceptional sensitivity and selectivity at ambient temperatures, with an ultra-fast response and recovery. The device effectively differentiates the exhaled breath patterns including slow, fast, oral and nasal breath, as well as post-exercise breath rates. Moreover, the sensor shows outstanding bending stability, repeatability, reliable and robust sensing performance and is capable of contactless sensing. The sensor was further employed with a user-friendly wireless interface to facilitate smartphone-enabled real-time breath monitoring systems. This work opens up numerous avenues for cost-effective, sustainable and versatile sensors with potential applications for Internet of Things-based flexible and wearable electronics. This article is part of the theme issue 'Celebrating the 15th anniversary of the Royal Society Newton International Fellowship'. [ABSTRACT FROM AUTHOR]

An all‐flexible self‐powering unit, combining a flexible perovskite solar mini‐module for energy conversion and ultra‐flexible screen‐printed interdigitated carbon supercapacitors on paper for energy storage, is designed and developed. Through a hybrid bifurcated structure, the supercapacitors are connected in series and neatly layered on a paper substrate with the perovskite solar mini‐module strategically placed on top for seamless integration. The photosupercapacitor quickly reaches saturated voltage under various light intensities (1 sun, 1000 lx, 500 lx, and 200 lx) and displays a self‐discharge time of over 2 minutes. It delivers peak overall and storage efficiencies of 2.8% and 23%, respectively, and exhibits an extensive potential window of 3.8 V, making it a prominent choice for real time applications in electronic systems. In a nutshell, the inherent flexibility of both the solar module and the storage system, coupled with the space‐saving design, and the extensive potential window of the hybrid photosupercapacitor paves the way for implementation in portable and wearable electronics operating in indoor environments, ushering a new era of more versatile and adaptable energy solutions. [ABSTRACT FROM AUTHOR]

The exponential demand for real-time monitoring applications has altered the course of sensor development, from sensor electronics miniaturization, e.g., resorting to printing techniques, to low-cost, flexible and functional wearable materials. Humidity sensing has been used in the prevention and diagnosis of medical conditions, as well as in the assessment of physical comfort. This paper presents a resistive flexible humidity sensor composed of silver interdigitated electrodes (IDTs) screen printed onto polyimide film and an active layer of multiwall carbon nanotubes (MWCNT) dispersed in a water-soluble polymer, polyvinyl alcohol (PVA). Different MWCNT/PVA sensor sizes and MWCNT percentages are tested to study their effect on the initial electrical resistance (Ri) values and sensor response at different humidity percentages. The results show that the Ri values decrease with the increase in % MWCNT. The sensor size did not influence the sensor response, while the % MWCNT affected the sensor behavior upon relative humidity (RH) increments. The 1% MWCNT/PVA sensor showed the best response, reaching a relative electrical resistance, ΔR/R0, of 509% at 99% RH. Comparable with other reported sensors, the produced MWCNT/PVA flexible sensor is simpler, greener and shows a good sensitivity to humidity, being easily incorporated in wearable monitoring applications, from sports to medical fields. [ABSTRACT FROM AUTHOR]

For this article, a low-cost, compact, and flexible inkjet-printed electromagnetic sensor was investigated for its chemical and biomedical applications. The investigated sensor design was used to estimate variations in the concentration of chemicals (ethanol and methanol) and biochemicals (hydrocortisone—a chemical derivative of cortisol, a biomarker of stress and cardiovascular effects). The proposed design's sensitivity was further improved by carefully choosing the frequency range (0.5–4 GHz), so that the analyzed samples showed approximately linear variations in their dielectric properties. The dielectric properties were measured using a vector network analyzer (VNA) and an Agilent 85070E Dielectric Probe Kit. The sensor design had a resonant frequency at 2.2 GHz when investigated without samples, and a consistent shift in resonant frequency was observed, with variation in the concentrations of the investigated chemicals. The sensitivity of the designed sensor is decent and is comparable to its non-flexible counterparts. Furthermore, the simulation and measured results were in agreement and were comparable to similar investigated sensor prototypes based on non-flexible Rogers substrates (Rogers RO4003C) and Rogers Droid/RT 5880), demonstrating true potential for chemical, biomedical applications, and healthcare. [ABSTRACT FROM AUTHOR]

Despite considerable interest, uniform and robust flexible transparent conducting electrodes (FTCEs) that can be seamlessly integrated and used for highly efficient large‐area flexible oganic light‐emitting diodes (OLEDs) remain elusive. In this study, a large‐area fabrication of uniform transparent electrodes for high‐performance flexible OLEDs by exploiting the rapid nanowelding process of silver nanowires (AgNWs) onto polyethylene terephthalate substrate under Xe‐lamp irradiation and mechanical pressing treatment is reported. The performance of AgNWs FTCEs is significantly enhanced by applying the Xe‐lamp beam irradiation for 5 s and subsequent compression at 20 MPa for 15 s, achieving a low sheet resistance of 26.5 Ω sq−1, a high transmittance of 95.2% (at 550 nm), and very smooth surfaces with root‐mean‐square of 5.4 nm. Meanwhile, the nanowelded AgNWs FTCEs maintain excellent electrical conductivity (only a 2.96% increase in ΔR/R0) after 1000 bending cycles. The resulting AgNWs FTCEs‐based green phosphorescent OLED achieves an unprecedented external quantum efficiency (EQE) of 23.7% and a current efficiency as high as 81.5 cd A−1. Benefiting from the uniform properties for resulting AgNWs FTCEs, the fabricated flexible OLED with a large area of 25 × 25 mm2 still retains a high EQE of 22.2% and a current efficiency of 78.0 cd A−1. [ABSTRACT FROM AUTHOR]

Highlights: The review provides a brief overview of the basic structure, operating mechanism, and key performance indicators of flexible graphene field-effect transistors. The review details the preparation strategy of flexible graphene field-effect transistors focusing on material selection and patterning techniques. The review analyzes the latest strategies for developing wearable and implantable flexible biomedical sensors based on flexible graphene field-effect transistors. Flexible electronics are transforming our lives by making daily activities more convenient. Central to this innovation are field-effect transistors (FETs), valued for their efficient signal processing, nanoscale fabrication, low-power consumption, fast response times, and versatility. Graphene, known for its exceptional mechanical properties, high electron mobility, and biocompatibility, is an ideal material for FET channels and sensors. The combination of graphene and FETs has given rise to flexible graphene field-effect transistors (FGFETs), driving significant advances in flexible electronics and sparked a strong interest in flexible biomedical sensors. Here, we first provide a brief overview of the basic structure, operating mechanism, and evaluation parameters of FGFETs, and delve into their material selection and patterning techniques. The ability of FGFETs to sense strains and biomolecular charges opens up diverse application possibilities. We specifically analyze the latest strategies for integrating FGFETs into wearable and implantable flexible biomedical sensors, focusing on the key aspects of constructing high-quality flexible biomedical sensors. Finally, we discuss the current challenges and prospects of FGFETs and their applications in biomedical sensors. This review will provide valuable insights and inspiration for ongoing research to improve the quality of FGFETs and broaden their application prospects in flexible biomedical sensing. [ABSTRACT FROM AUTHOR]

The flexible system of wind turbines refers to the components such as blades, towers, and rotor shafts that are subjected to external forces such as wind loads, inertial forces, and gravity during operation, resulting in deformation and vibration. This paper proposes that dynamic response analysis of the flexible system, through the response data, put forward improvement measures to improve the stability. The flexible dynamic response of wind turbine was analyzed. The fluid dynamics and structural dynamics of wind turbine are analyzed by the finite element method, and the flow chart is combined to get the wind turbine velocity, pressure, shear stress, and vorticity distribution nephogram. The results provide a reference value for monitoring structural state dynamics parameters of large wind turbines. Wind power generation technology is relatively mature, and its proportion in the field of power generation is gradually increasing. Wind energy is inexhaustible and can occupy a place in the development and utilization of new energy for a long time. This study provides an important reference for determining the dynamic parameters of wind turbine operation and improves the stability and reliability of wind turbine operation. The results provide a reference value for monitoring structural state dynamics parameters of large wind turbines. [ABSTRACT FROM AUTHOR]

Effective optical limiters (OLs) are necessary devices for the protection of various sensitive photo‐detectors, cameras, infrared sensors, or even the human eyes once encountering unexpected high‐intensity illumination or laser blinding attacks. Vanadium dioxide (VO2) shows pronounced infrared switching behavior across the phase transition, which is considered as an idea optical limiter for broad‐band infrared laser protection. However, the self‐adapting optical limiter function based on VO2 is quite difficult to realize since the open‐state absorptance of the VO2 layer is always very low, which makes the laser irradiation cannot trigger the phase transition quickly. In the current study, a self‐excited VO2 infrared optical limiter is proposed, which is integrated by a transferred VO2 layer, InGaAs micro/nano wires, and a local heater. Based on the"optical response–electric heating" strategy, the phase transition of VO2 layer can be quickly triggered once the incident laser beam intensity exceeds the pre‐set threshold value. In addition, this integrated device has an excellent switching ratio, flexible controllability, and stability. This work achieves a practical VO2 optical limiter device and provides a promising strategy for developing VO2‐based integrated multifunctional devices in the future. [ABSTRACT FROM AUTHOR]

A multifunctional sensor comprising flexible and transparent ultraviolet (UV) photodetectors (PDs) with strain gauges based on Ag nanowire (AgNW)@ZnO nanorods (ZnONRs) was fabricated using a cost-effective, simple, and efficient method. High-aspect ratio silver nanowires were synthesized using the polyol method. An AgNW@ZnONR composite was formed via the hydrothermal method to ensure the multifunctional capability of the flexible sensors. After refining the process parameters, the size of the ZnO nanorods was decreased to fabricate pliable multifunctional sensors using AgNW@ZnONRs. At a deposition of 0.207 g of AgNW@ZnONRs, the sensor achieves its maximum switching ratio and fastest response time under conditions of 2000 μW/cm2 UV optical power density. With a ton (rise time) of 2.7 s and a toff (fall time) of 2.3 s, the ratio of Ion to Ioff current is 1151. Additionally, the sensor's maximum optical current value correlates linearly with UV light's power density. The maximum response current increased from 222.5 pA to 588.1 pA, an increase of 164.3%, when the bending angle was increased from 15° to 90° for the sensor with a deposition of 0.276 g of AgNW@ZnONRs. There was no degradation in the response of the sensors after 10,000 bending cycles, as they have excellent stability and repeatability, which means they can meet the requirements of wearable sensor applications. Therefore, there is great potential for the practical application of multifunctional AgNW@ZnONRs in flexible sensors. [ABSTRACT FROM AUTHOR]

Photomultiplication‐type organic photodetectors (PM‐OPDs) effectively amplify photogenerated signals, eliminating the need for external amplifiers and simplifying detection systems. Current designs require high bias voltages, leading to significant power consumption. This study introduces PM‐OPDs with reduced bias voltage by incorporating a hole‐blocking layer (HBL) between the active layer and electrode. Deep HOMO level and thin HBL facilitate hole accumulation and energy level bending, lowering bias voltage and enhancing electron injection. The elevated LUMO level of the HBL minimizes non‐radiative recombination and prolongs the lifetime of accumulated holes, resulting in greater photogains. Four HBLs—BCP, PFN‐Br, BPhen, and C60—are explored with ZnO serving as an electron transporting layer (ETL). By applying a bi‐directional bias of ±0.5 V, PM‐OPDs are enabled to operate with an EQE of 19560% and a detectivity of 2.8 × 1013 Jones. The versatility of this mechanism is validated across three active layer combinations. Compared to commercial silicon photodetector, the flexible PM‐OPDs achieved a 139.3‐fold increase in photocurrent in photoplethysmography under faint light conditions. This work presents a promising strategy for developing bi‐directional biased PM‐OPDs with reduced power consumption while maintaining high gains for various practical applications. [ABSTRACT FROM AUTHOR]

Brain-computer interfaces (BCIs) represent a cutting-edge field in neuroengineering, facilitating direct communication between the brain and external devices. With applications ranging from the study of neuroscience to medical diagnosis and therapy, virtual reality, and cognitive augmentation, BCIs are at the forefront of technological advancement. Traditional rigid neural probes used in BCIs face challenges in maintaining long-term, stable recordings at the single-neuron level. Furthermore, achieving high electrode density while minimizing flexural rigidity remains a challenge with conventional rigid materials. In this perspective, we emphasize the importance of spatiotemporal scalability in the advancement of neural probes. We discuss the necessary material properties to achieve high spatiotemporal scalability, which is critical for long-term stability in neural recordings and for increasing electrode counts and density. We review recent developments in flexible and soft material systems, as well as fabrication strategies to meet these challenges. Our analysis highlights the potential of flexible and soft electronics to overcome existing limitations and realize the full potential of next-generation BCIs. [ABSTRACT FROM AUTHOR]

Aircraft in both the commercial and defense sectors undergo significant disassembly in order to access and inspect critical structures and components. To limit the extent of disassembly needed and thus increase system availability, the concept of mobile robotic inspection has been notionally discussed for over 20 years. Notably this interest in mobile robotic inspection extends beyond aircraft to include civil infrastructure, pipelines, and nuclear plants where some robotic platforms are currently in use. However, the unique challenges associated with complex aircraft systems and structures remain to be addressed. With advancements in the fields of durable polymers, autonomous materials, flexible electronics, tailorable actuation, and others, soft robotics are an increasingly viable solution to the challenge of inspection in access-limited spaces. This perspective article will overview key advancements in pertinent technical areas and highlight scientific barriers to wide-spread use and acceptance of soft robotics for aircraft inspection. [ABSTRACT FROM AUTHOR]

The flexible piezoelectric pressure sensor is essential in areas such as machine sensing and human activity monitoring. Here, 0-dimensional PZT piezoelectric ceramic nanoparticles with carbon coating were synthesized by a surface-modified technique. The excellent electrical conductivity of the carbon shell causes redistribution and accumulation of mobile charges in the carbon layer, resulting in a greatly increased piezoelectric effect by inducing an enhanced electric field. A series of organic–inorganic composite films were prepared by the spin-coating method using polydimethylsiloxane (PDMS) as the matrix. The as-fabricated flexible PZT@C/PDMS composite film with 40 wt% PZT@C powder exhibits an excellent output voltage of ~74 V, a peak of output current ~295 nA, as well as a big sensitivity of 5.26 V N−1. Moreover, the composite film can be used as a pressure sensor to detect changes in force as well as for monitoring limb movements such as finger flexion, wrist flexion, and pedaling. This study reveals the promising applications of flexible 40%PZT@C/PDMS composite film for limb motion monitoring and pressure sensing. [ABSTRACT FROM AUTHOR]

Copyright of Automobile Technology & Material is the property of Automobile Technology & Material Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Owing to promising room‐temperature thermoelectric properties, n‐type Ag2Se has been considered as an alternative for Bi2Te3. Herein, a carrier separation strategy is realized by compositing an insulating electron donor, polyethyleneimine (PEI), with the n‐type Ag2Se. Inhomogeneous distribution of PEI can attract the minority carriers (holes) in the n‐type Ag2Se matrix, while the separated minority carriers can avoid significant scattering of the main carriers based on coulomb repulsion, leading to record‐high carrier mobility of 1551.99 cm2 V−1 s−1 and an improved S2σ of 22.39 µW m−1 K−2 at 300 K for 6 mol% PEI/Ag2Se composite film. Moreover, with PEI acting as a binder, the resistance of 6 mol% PEI/Ag2Se composite film only increases by 6.5% after bending 1000 cycles at the radius of 6 mm, showing high stability. The assembled flexible device based on 6 mol% PEI/Ag2Se composite films exhibits an excellent power density of 73.93 W m−2 at a temperature difference of 50 K, showing potential applications in powering generation for wearable electronics. [ABSTRACT FROM AUTHOR]

Metasurface absorbers (MSAs) are of significant importance in a wide range of applications, such as in the field of stealth technology. Nevertheless, conventional designs demonstrate limited flexible characteristics and a lack of transparency, hence constraining their suitability for certain radar stealth applications. This study introduces a novel MSA operating in the broad microwave range, which exhibits both optical transparency and flexibility. The structure consists of a flexible substrate made of polyvinyl chloride (PVC), along with a resistive film composed of indium tin oxide (ITO). The proposed structure exhibits the ability to effectively absorb over 90% of the energy carried by incident electromagnetic (EM) waves across the frequency range of 9.85–41.76 GHz within an angular range of 0° to 60°. In addition, to assess the efficacy of the absorption performance, an examination of the radar cross-section (RCS) characteristics is conducted. The results indicate a reduction of over 10 dB across the aforementioned broad frequency spectrum, regardless of the central angle. [ABSTRACT FROM AUTHOR]

The removal of foreign bodies (FBs) from the airways of children is a critical procedure that can avert serious complications. While both flexible and rigid bronchoscopy techniques are employed for this purpose, their comparative efficacy and safety remain subjects of debate. Therefore, we conducted this investigation to compare between both procedures. Studies comparing flexible to rigid bronchoscopy (n = 14) were identified by searching PubMed, Scopus, Web of Science, Cochrane Library, and Google Scholar. We performed comparative meta-analyses of reported presentation characteristics and clinical outcomes, using fixed- and random-effects models. A diverse range of FB types and locations were identified. No difference was observed in the success rate of FB removal between flexible and rigid bronchoscopy (logOR = 0.27; 95%CI: −1.91:2.45). The rate of negative first bronchoscopy was higher in the flexible compared to the rigid group (logOR = 2.68; 95%CI: 1.68:3.67). Conversion rates to the alternative method were higher in the flexible bronchoscopy group. The overall complication rates were similar between both methods; however, the risk of desaturation was significantly lower with flexible bronchoscopy (logOR = −2.22; 95%CI: −3.36:−1.08). Flexible bronchoscopy was associated with a shorter length of hospital stay. The choice of bronchoscopy technique should be tailored to individual case characteristics. [ABSTRACT FROM AUTHOR]

This paper comprehensively analyses the specific absorption rate (SAR) for an ultra-wideband (UWB) wearable antenna designed for body-centric communication applications. The study is motivated by the extent of electromagnetic radiation in our surroundings, raising worries about health for wireless device users and wearable devices that utilize UWB technology. The proposed antenna is made of a foam substrate having a dielectric constant of 1.07, a thickness of 2 mm with a dimension of 36 × 48 × 2 mm 3 . The designed structure optimizes UWB (3.1–10.6 GHz) in connotation with the ISM band of 2.4 GHz. The proposed antenna works well over the wide frequency range resulting in a bandwidth of 11.53 GHz and a total gain of 8.05 dBi. An excellent impedance matching is obtained by creating a stub at the feed point which gives the maximum value of S11 as − 44.88 dB. The analysis focuses on the SAR values to measure the rate of electromagnetic energy absorption by human tissues over 1 and 10 g by constructing an equivalent three-layer body phantom model. The results indicate that the proposed antenna exhibits SAR values well within the limits set by international standards of 1.6 W/kg averaged over 1 g of tissue and 2 W/kg for 10 g of tissue, while maintaining efficient radiation characteristics across the UWB spectrum. [ABSTRACT FROM AUTHOR]

The next‐generation bionics and, more specifically, wearable and implantable bioelectronics require wireless, battery‐free, long‐term operation and seamless bio‐integration. Design considerations, materials choice, and implementation of efficient architectures have become crucial for the fabrication and deployment of wireless devices, especially if they are flexible or soft. Wireless power and data transfer represent key elements for the development of robust, efficient, and reliable systems for health monitoring, advanced disease diagnosis and treatment, personalized medicine. Here, the recent advances in materials and technologies used for wireless energy sourcing and telemetry in bio‐integrated flexible bionic and bioelectronic systems are reviewed. The study tackles different challenges related to mechanical compliance, low thickness, small footprint, biocompatibility, biodegradability, and in vivo implementation. The work also delves into the main figures of merit that are mostly adopted to quantify the wireless power/data transfer performances. Lastly, the pivotal applications of wearable and implantable wireless bionics/bioelectronics are summarized, such as electrical stimulation/recording, real‐time monitoring of physiological parameters, light delivery trough optical interfaces, electromechanical stimulation via ultrasounds, highlighting their potential for future implementation and the challenges related to their commercialization. [ABSTRACT FROM AUTHOR]

Iron-based anode materials usually exhibit an unsatisfactory rate performance and poor cycle stability during Li+ storage. Herein, ultrathin hexagonal Fe3O4 nanosheets are embedded in nitrogen-doped carbon nanofibers (hexa-Fe3O4@N-CNF), boosting the Li+ diffusion kinetics and maintaining cycling stability. The ultrathin hexa-Fe3O4 nanosheets possess a short Li+ diffusion pathway, while N-CNF displays excellent conductivity, both of which contribute to the rapid insertion/extraction of Li+. The iron-induced thermal-catalyzed N-CNF manifests enhanced mechanical stability due to its increased graphitization degree, which effectively alleviates the mechanical stress resulting from the volume change of the hexa-Fe3O4 during Li+ storage, thereby enhancing the cyclic stability of hexa-Fe3O4@N-CNF. The compressed anode of hexa-Fe3O4@N-CNF presents a high mass loading (3.3 mg cm–2) and is coupled with a flexible cathode (activated carbon casted onto N-CNF) to assemble the quasi-solid-state lithium-ion hybrid capacitor (LIHC), enabling the attainment of high volumetric power/energy density (66.5 W h L–1 at 117.9 W L–1 and 38.5 W h L–1 at 11785.7 W L–1). When the LIHC is bent at 180°, its Li+ storage performance illustrates a negligible degradation. Additionally, LIHC features a low self-discharge rate (∼14.2 mV h–1). Overall, the long-term cycle stability, high power/energy density, low self-discharge rate, as well as mechanical robustness render this LIHC a suitable candidate for flexible energy storage applications. [ABSTRACT FROM AUTHOR]

Flexible photoelectrochemical (PEC) based sensors have been extensively investigated for noninvasive healthcare monitoring. However, known electrode materials struggle to combine technologically relevant metrics of high sensitivity and flexibility due to their low electrical conductivity and fragile mechanical properties. Herein, a flexible PEC‐based sensor for dopamine (DA) detection is presented by integrating highly conductive and flexible MXene between CdS quantum dots and g‐C3N4 with suitable energy level matching. Theoretical calculations reveal that the interfaces of constructed PEC electrodes with enhanced electronic conductivity derived from MXene not only improve the electron transfer kinetics, but form built‐in electric fields at the interfaces, facilitating the separation efficiency of electron–hole pairs. As a result, the as‐prepared sensors display the combined advantages of a wide detection range (1 nM–0.1 mM), low detection limit (0.48 nM), high stability, selectivity, and repeatability for DA detection. Building on these metrics, a scalable screen‐printing method is further developed for integrating the sensors on flexible platforms. These all‐integrated PEC‐based sensors exhibit stable photocurrent signals under different bending angles and bending cycles. Therefore, this work demonstrates the scalable development of flexible PEC‐based sensors for the sensitive detection of DA and holds promise for the future development of noninvasive healthcare monitoring. [ABSTRACT FROM AUTHOR]

Inorganic semiconductor gas sensors, being widely utilized in gas‐sensing applications, face significant challenges in attaining mechanical flexibility and humidity resistance in wearable sensing fields. Herein, a highly flexible, breathable, and hydrophobic all‐inorganic self‐supporting nanofiber (NF) gas sensor is developed using electrospinning combined with thermal sulfidation approach. This innovative sensor features a bilayer configuration, with an amorphous SiO2 nanofiber substrate layer and an interwoven SiO2 and SnO2–SnS2 nanofiber active layer. The relatively low elastic modulus of the amorphous SiO2 nanofibers, combined with the three‐dimensional network interwoven structure, endow the SnO2–SnS2–SiO2/SiO2 sensor with superior mechanical flexibility. The sensor exhibits excellent sensitivity, selectivity, moisture resistance, and cycling stability (>10 000 cycles at 140° bending) to both high and low concentration NO2. Notably, an excellent flexible detecting capability of the sensor to NO2, an asthma‐related biomarker, is demonstrated at ultralow concentrations (≈25 ppb) in simulated exhaled breath environments. The enhanced moisture resistance is attributed to the effective inhibition of hydrogen bond formation from H2O molecules by the Sn─S bonds formed through sulfidation of SnO2 nanofibers. This work represents a substantial advancement in the universal fabrication of flexible, breathable and moisture‐resistant inorganic semiconductor sensors for wearable breath sensing applications. [ABSTRACT FROM AUTHOR]

Double-row tapered roller bearings are one of the main bearings for semi-direct drive wind turbines. Its performance is directly related to its service life. At present, the research of double-row tapered roller bearings is mainly focused on single bearing, and the research of multicomponent bearing system is rarely considered comprehensively. In this paper, a rigid-flexible hybrid multi-force analysis model considering multiple components is proposed, which can be used for the analysis and research of system models. The results show that the contact load is similar to the theoretical contact load. The contact stress distribution of the left row roller along the prime line is more uniform, and there is only one row bearing near zero of the roller. The error between the simulation results and the theoretical calculation results is 4.56%, which is within the allowable range of error, so it is feasible to analyze the contact stress of the proposed rigidflexible mixed multi-mechanical system model. [ABSTRACT FROM AUTHOR]

The purpose of this study is to describe how the Provincial Smart-City Agency in Indonesia adapted agile practices. Implementing agile in conventional government is challenging because formal regulations dictate that a government entity operates by default. While agile approach demands a quick and effective response to shifting circumstances, its deployment frequently contrasts with the established bureaucracy. Considering practicing agile in government organizations, this paper asks how the Provincial Smart-City Agency adapts an agile approach to comply with the conventional government. This case study uses a qualitative method and NVivo software to organize and analyze data. Data were collected through internship observation from April to August 2022 and semi-structured interviews between June and September 2022. Data triangulation was used to validate the informants’ information. By describing the adaptation of agile practices in a provincial smart city agency, this paper expands knowledge on the adaptation of government organizations to implement agile concepts within a conventional bureaucracy that previous studies did not discuss. The result of this study contributes to agile adaptation practice to help government organizations start implementing agile practice by learning from the Provincial Smart-City Agency's success through six elements adapted to enable agility: the innovative structure of the organization, flexible working hours for non-permanent employees, workflow interaction, operational flexibility in the workplace, categorization of work into dynamic flexible tasks and routine repetitive tasks, and work location. These elements are affected by several factors, some of which arise from inherent characteristics of the agile components that influence the other components. [ABSTRACT FROM AUTHOR]

This study explores the development and performance of bistable materials, emphasizing their potential applications in aero-vehicles and high-stress environments. By integrating soft and hard materials within a composite structure, the research demonstrates the creation of bistable composites that exhibit remarkable flexibility and rigidity. Advanced simulations using COMSOL Multiphysics and 3D-printed prototypes reveal that these materials effectively absorb and dissipate stress, maintaining structural integrity under high-pressure conditions. Compression tests highlight the ability of bistable structures to bear significant loads, distributing stress efficiently across multiple layers. The innovative proposal of combining stiff and flexible materials within a single unit cell enhances bistable behavior, offering superior energy absorption and resilience. This work underscores the promise of bistable materials in advancing materials science, providing robust solutions for aerospace, automotive, and protective gear applications and paving the way for future research in optimizing bistable structures for diverse engineering challenges. [ABSTRACT FROM AUTHOR]

Vibration sensors are widely applied in the detection of faults and analysis of operational states in engineering machinery and equipment. However, commercial vibration sensors with a feature of high hardness hinder their usage in some practical applications where the measured objects have irregular surfaces that are difficult to install. Moreover, as the operating environments of machinery become increasingly complex, there is a growing demand for sensors capable of working in wet and humid conditions. Here, we present a flexible, superhydrophobic vibration sensor with parallel microcracks. The sensor is fabricated using a femtosecond laser direct writing ablation strategy to create the parallel cracks on a PDMS film, followed by spray-coating with a conductive ink composed of MWCNTs, CB, and PDMS. The results demonstrate that the developed flexible sensor exhibits a high-frequency response of up to 2000 Hz, a high acceleration response of up to 100 m/s2, a water contact angle as high as 159.61°, and a linearity of 0.9812 between the voltage signal and acceleration. The results indicate that the sensor can be employed for underwater vibration, sound recognition, and vibration monitoring in fields such as shield cutters, holding significant potential for mechanical equipment vibration monitoring and speech-based human–machine interaction. [ABSTRACT FROM AUTHOR]

Mechanical energy harvesters made from soft and flexible materials can be employed as energy sources for wearable and implantable devices. However, considering how human organs and joints expand and bend in many directions, the energy generated in response to a mechanical stimulus in only one direction limits the applicability of mechanical energy harvesters. Here, we report carbon nanotube (CNT) sheets/an elastomer bilayer harvesting electrode (CBHE) that converts two-axis mechanical stimulation into electrical energy. The novel microwinkled structure of the CBHE successfully demonstrates an electrochemical double-layer (EDL) capacitance change from biaxial mechanical stimulation, thereby generating electrical power (0.11 W kg−1). Additionally, the low modulus (0.16 MPa) and high deformability due to the elastomeric substrate suggest that the CBHE can be applied to the human body. [ABSTRACT FROM AUTHOR]

The increasing need for wearable health monitoring gadgets has led to the development of better antenna technology for reliable wireless communication in small, wearable designs. This paper introduces a new way to create a wearable Multiple-Input Multiple-Output (MIMO) antenna specifically for health monitoring. Working at the sub 6 GHz frequency, this antenna allows fast data transfer and effective communication between wearable devices and healthcare systems. The selection of polylactic acid (PLA) as the substrate material offers several advantages for wearable applications. PLA boasts superior flexibility, simplifies the fabrication process, and ensures compatibility with the form factor of wearable devices. The antenna’s construction involves meticulous steps like resin preparation, extrusion, and surface treatments to achieve the desired dimensions and optimize its performance. The uniqueness of this work lies in of developing a smaller-sized (29x19mm²) antenna to improve signal reception with -45 dB isolation between the antennas and ensure dependable wireless communication. Through meticulous testing and model construction, the antenna design is refined by incorporating additional antenna components to enhance signal quality, mitigate issues, and optimize overall system performance. [ABSTRACT FROM AUTHOR]

Background: We aim to describe our experience with bronchoscopy to diagnose and relieve tracheobronchial obstruction in anticipation of decannulation in children on extracorporeal membrane oxygenation (ECMO) support. Methods: A retrospective cohort study of children on ECMO between 1/2018 and 12/2022. Results: A total of 107 children required ECMO support during the study period for cardiac (n = 48, 45%), pulmonary (n = 38, 36%), or cardiopulmonary dysfunction (n = 21, 20%). Thirty‐seven (35%) patients underwent 99 bronchoscopies while on ECMO. Most (76%, n = 75) experienced no improvement or worsening of chest radiography 24 hours following bronchoscopy. Clinical improvement in tidal volumes 48 hours after the first bronchoscopy was noted in 13/25 patients with available data (p = 0.05). Adverse events were seen in 18 (49%) patients who underwent bronchoscopy, including pneumothorax (n = 8, 22%), pneumonia (n = 7, 19%), pulmonary hemorrhage (n = 6, 16%), and sepsis (n = 5, 14%). ECMO courses were longer (25.4 ± 37.2 vs 6.1 ± 8.8 days, p < 0.0001) and more likely to be complicated by pneumonia (p = 0.0004) and sepsis (p = 0.047) in patients who underwent bronchoscopy compared with those who did not. Adverse events following bronchoscopy were associated with the number of bronchoscopies (p = 0.0003) and the presence of obstructive materials but not with the type of bronchoscopy or indication for ECMO. Mortality rates were similar between patients who underwent bronchoscopy and those who did not. Conclusion: Children requiring bronchoscopy represent a subset of the sickest children on ECMO. Bronchoscopy may provide benefit in children with persistent cardiopulmonary failure who could not otherwise be decannulated. Adverse events are associated with the number of bronchoscopies and the presence of obstructive material. Level of Evidence: 4 Laryngoscope, 134:4134–4140, 2024 [ABSTRACT FROM AUTHOR]

To investigate the impact of electrode structure on Electrical Stimulation Therapy (EST) for chronic wound healing, this study designed three variants of flexible microelectrodes (FMs) with Ag-Cu coverings (ACCs), each exhibiting distinct geometrical configurations: hexagonal, cross-shaped, and serpentine. These were integrated with PPY/PDA/PANI (3/6) (full name: polypyrrole/polydopamine/polyaniline 3/6). Hydrogel dressing comprehensive animal studies, coupled with detailed electrical and mechanical modeling and simulations, were conducted to assess their performance. Results indicated that the serpentine-shaped FM outperformed its counterparts in terms of flexibility and safety, exhibiting minimal thermal effects and a reduced risk of burns. Notably, FMs with metal coverings under 3% demonstrated promising potential for optoelectronic self-powering capabilities. Additionally, simulation data highlighted the significant influence of hydrogel non-uniformity on the distribution of electrical properties across the skin surface, providing critical insights for optimizing EST protocols when employing hydrogel dressings. [ABSTRACT FROM AUTHOR]

Highlights The sandwich-structured flexible mechanoluminescent sensor (SFLC) film shows great application potential as wireless wearable strain sensor and encryption device. System-level integration of SFLC film with deep learning-based artificial intelligence enables fast and accurate interpretation of color data to strain values with automatic correction of errors caused by varying color temperatures. The smart glove wearable sensor based on the SFLC film combined with deep learning neural network enables fast and accurate hand gesture recognition.

Abstract The flexible system of wind turbines refers to the components such as blades, towers, and rotor shafts that are subjected to external forces such as wind loads, inertial forces, and gravity during operation, resulting in deformation and vibration. This paper proposes that dynamic response analysis of the flexible system, through the response data, put forward improvement measures to improve the stability. The flexible dynamic response of wind turbine was analyzed. The fluid dynamics and structural dynamics of wind turbine are analyzed by the finite element method, and the flow chart is combined to get the wind turbine velocity, pressure, shear stress, and vorticity distribution nephogram. The results provide a reference value for monitoring structural state dynamics parameters of large wind turbines. Wind power generation technology is relatively mature, and its proportion in the field of power generation is gradually increasing. Wind energy is inexhaustible and can occupy a place in the development and utilization of new energy for a long time. This study provides an important reference for determining the dynamic parameters of wind turbine operation and improves the stability and reliability of wind turbine operation. The results provide a reference value for monitoring structural state dynamics parameters of large wind turbines.

Highlights The review provides a brief overview of the basic structure, operating mechanism, and key performance indicators of flexible graphene field-effect transistors. The review details the preparation strategy of flexible graphene field-effect transistors focusing on material selection and patterning techniques. The review analyzes the latest strategies for developing wearable and implantable flexible biomedical sensors based on flexible graphene field-effect transistors.

Abstract This paper comprehensively analyses the specific absorption rate (SAR) for an ultra-wideband (UWB) wearable antenna designed for body-centric communication applications. The study is motivated by the extent of electromagnetic radiation in our surroundings, raising worries about health for wireless device users and wearable devices that utilize UWB technology. The proposed antenna is made of a foam substrate having a dielectric constant of 1.07, a thickness of 2 mm with a dimension of $$36\times 48\times 2 {\text{mm}}^{3}$$ 36 × 48 × 2 mm 3 . The designed structure optimizes UWB (3.1–10.6 GHz) in connotation with the ISM band of 2.4 GHz. The proposed antenna works well over the wide frequency range resulting in a bandwidth of 11.53 GHz and a total gain of 8.05 dBi. An excellent impedance matching is obtained by creating a stub at the feed point which gives the maximum value of S11 as − 44.88 dB. The analysis focuses on the SAR values to measure the rate of electromagnetic energy absorption by human tissues over 1 and 10 g by constructing an equivalent three-layer body phantom model. The results indicate that the proposed antenna exhibits SAR values well within the limits set by international standards of 1.6 W/kg averaged over 1 g of tissue and 2 W/kg for 10 g of tissue, while maintaining efficient radiation characteristics across the UWB spectrum.

Abstract Mask face recognition has recently gained increasing attention in the current context. Face mask occlusion seriously affects the performance of face recognition systems, because more than 75% of the face area remains unexposed and the mask directly causes an increase in intra-class differences and a decrease in inter-class separability in the feature space. To improve the performance of face recognition model against mask occlusion, we propose a fast and efficient method for mask generation in this paper, which can avoid the need for large-scale collection of real-world mask face training sets. This approach can be embedded in the training process of any mask face model as a module and is very flexible. Experiments on the MLFW, MFR2 and RMFD datasets show the effectiveness and flexibility of our approach that outperform the state-of-the-art methods.

Abstract We investigated the techno-economic feasibility and power supply potential of enhanced geothermal systems (EGS) across the contiguous United States using a new subsurface temperature model and detailed simulations of EGS project life cycle. Under business-as-usual scenarios and across depths of 1–7 kilometers, we estimated 82,945 GW and 0.65 GW of EGS supply capacity with lower levelized cost of electricity than conventional hydrothermal and solar photovoltaic projects, respectively. Considering the scenario of flexible geothermal dispatch via wellhead throttling and power plant bypass, these estimates climbed up to 184,112 GW and 44.66 GW, respectively. The majority of EGS supply potential was found in the Western and Southwestern regions of the United States, where California, Oregon, Nevada, Montana, and Texas had the greatest EGS capacity potential. With advanced drilling rates based on state-of-the-art implementations of recent EGS projects, we estimated an average improvement of 25.1% in the levelized cost of electricity. These findings underscored the pivotal role of flexible operations in enhancing the competitiveness and scalability of EGS as a dispatchable renewable energy source.