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Transparent and flexible metamaterial absorbers can provide solutions for electromagnetic compatibility and electromagnetic radiation pollution. They also play key roles in platforms with optical windows that require low detectability and immunity to electromagnetic interference. Due to the lack of active adaptability to complex electromagnetic environments, early metamaterial absorbers need to be redesigned and manufactured once the application scenarios change. The new two-dimensional material graphene provides a practical technical approach for the realization of transparent tunable absorbers. In this work, we propose a polarization-insensitive dual-tunable microwave absorber based on graphene metasurface. By controlling two separate bias voltages applied to patterned graphene or continuous graphene, independent dynamic regulation of electromagnetic wave absorption frequency and amplitude is achieved. It also possesses the features of optical transparency and flexibility. The measurement results show that the absorption frequency can be shifted from 9.8 to 11.3 GHz, the peak absorption rate at each absorption frequency remains above 99.6%, and the reflection amplitude modulation can be achieved simultaneously at each absorption frequency. The proposed absorber integrates multiple modulation functions for electromagnetic waves, and the overall structure is optically transparent and flexible. Therefore, it can contribute to many practical wave absorbing applications. [ABSTRACT FROM AUTHOR]

This letter proposes a method to calculate the expected value of the shielding effectiveness of a composite material slab, including a planar array of randomly oriented metal helices as chiral particles. Helix‐loaded concrete composite materials are advantageous for electromagnetic interference shielding applications. While planar periodic arrays of chiral particles have been extensively studied, this research discusses a non‐periodic array in which the helical particle axis direction in each unit cell is random. This method estimates the slab's shielding effectiveness by defining it as a random variable expanded into three independent basis‐like functions. Comparisons with full‐wave simulations show acceptable agreement across a wide frequency range, with a total RMS error of 0.9 dB. This study additionally includes an experimental measurement to validate the proposed method. This technique provides the initial step in developing an analytical method to analyse and estimate the transmitted power of general structures using a stochastic approach. Examples include concrete composites containing randomly distributed helical steel particles with significant shielding effectiveness. [ABSTRACT FROM AUTHOR]

With the development of electronic devices and wireless communication technology, the quality of human life has improved. However, shielding from electromagnetic interference (EMI) is required due to device malfunctions and harmful effects on human health. Polymer‐based shielding materials getting much attention due to their light weight, flexibility, good processability, and other desirable traits. However, achieving consistent dispersion of conductive fillers and optimizing the balance between electrical, mechanical, and thermal properties remain challenges despite the advantages of polymer‐based materials. Especially, epoxy resins are promising polymer materials for EMI shielding applications due to their excellent mechanical strength, chemical resistance, and excellent adhesive properties. Additionally, epoxy resin exhibits remarkable processability allowing for various fabrication techniques such as casting, molding, and three‐dimensional printing. However, one of the significant drawbacks of epoxy resin is the difficulty in achieving uniform dispersion of conductive fillers within the epoxy matrix. In this study, we propose an iron‐nickel alloy (FeNi) embedded in an epoxy matrix (FeNi/Epoxy) for EMI shielding material. It is manufactured by facile fabrication process due to the advantages of epoxy, which has excellent processability. EMI shielding effectiveness at 12 GHz is enhanced from 9.12 to 17.86 dB by the increase of FeNi concentrations. Furthermore, thermal and mechanical properties were improved by the increase of FeNi concentration. Thermal conductivity for efficient heat dissipation is increased from 0.63 to 1.49 Wm−1 K−1. Moreover, polydopamine (PDA) was employed as a surface coating material for FeNi to overcome the non‐uniform dispersion of FeNi particles in the epoxy matrix. Surface coating by PDA significantly enhanced the dispersion uniformity and strengthened the adhesion between the filler and matrix. Elastic modulus is greatly increased from 83.03 MPa to 1.29 GPa by the surface coating. The enhancement of mechanical properties is derived from the chemical bonds between the filler and matrix. [ABSTRACT FROM AUTHOR]

The ongoing global shift towards sustainability in electrical engineering necessitates novel materials that offer both ecological and technical benefits. Biomass‐derived carbon materials (BCMs) are emerging as cornerstones in this transition due to their sustainability, cost‐effectiveness, and versatile properties. This review explores the expansive role of BCMs across various electrical engineering applications, emphasizing their transformative impact and potential in fostering a sustainable technological ecosystem. The fundamentals of BCMs are investigated, including their unique structures, diverse synthesis procedures, and significant electrical and electrochemical properties. A detailed examination of recent innovations in BCM applications for energy storage, such as batteries and supercapacitors, and their pivotal role in developing advanced electronic components like sensors, detectors, and electromagnetic interference shielding composites has been covered. BCMs offer superior electrical conductivities, tunable surface chemistries, and mechanical properties compared to traditional carbon sources. These can be further enhanced through innovative doping and functionalization techniques. Moreover, this review identifies challenges related to scalability and uniformity in properties and proposes future research directions to overcome these hurdles. By integrating insights from recent studies with a forward‐looking perspective, this paper sets the stage for the next generation of electrical engineering solutions powered by biomass‐derived materials, aligning technological advancement with environmental stewardship. [ABSTRACT FROM AUTHOR]

Polylactic acid (PLA) composites with multifunctional properties and minimal filler content are increasingly in demand across various industries. However, achieving a balance between high mechanical strength, electrical conductivity, thermal conductivity, and electromagnetic interference (EMI) shielding remains challenging. In this study, a dual‐processing strategy combining Pickering emulsion templating and melt blending is presented to hybridize 1D carbon nanotubes (CNTs) and 2D graphene nanoplatelets (GNPs) within a PLA matrix. This approach successfully forms a stable dual‐filler network, ensuring uniform dispersion of the fillers. The results show that this method significantly enhances the performance of the resulting PM‐PGxCy composites (P: Pickering emulsion; M: melt blending; x and y: mass fractions of GNPs and CNTs, respectively). Specifically, the PM‐PG1.43C1.43 composite exhibits remarkable improvements in mechanical strength (56.2 MPa), electrical conductivity (43.5 S m−1), EMI shielding effectiveness (20.1 dB), and thermal conductivity (0.34 W m·K−1), outperforming composites prepared using either method alone. These findings indicate that the dual‐processing strategy effectively combines 1D and 2D fillers, facilitating superior interfacial interactions and enhancing the multifunctional properties of PLA‐based composites. This study offers a new approach to achieving high‐performance PLA composites with low filler content, offering significant potential for applications in electronics, packaging, and EMI shielding technologies. [ABSTRACT FROM AUTHOR]

Microwave absorbing materials play an increasingly important role in modern electronic warfare technology for enhancing electromagnetic compatibility and suppressing electromagnetic interference. High‐entropy ceramics (HECs) possess extraordinary physical and chemical properties, and more importantly, the high tunability of multi‐component HECs has brought new opportunities to microwave absorbing materials. Rich crystallographic distortions and multi‐component occupancies enable HECs to have highly efficient microwave absorption properties, excellent mechanical properties, and thermal stability. Therefore, the structural advantages of HECs are integrated from comprehensive perspectives, emphasizing on the role of dielectric and magnetic properties in the absorption phenomenon. Strategies are proposed to improve the microwave absorption capacity of HECs, including composition optimization, microstructure engineering, and post‐treatment technology. Finally, the problems and obstacles associated with high‐entropy materials (HEMs) research are discussed. The innovative design concepts of high‐entropy microwave absorbing ceramics are highlighted. [ABSTRACT FROM AUTHOR]

This study presents a facile self‐healing electromagnetic interference (EMI) shielding composite by sandwiching a layer of silver nanowires (AgNWs) between two layers of self‐healing polyurethane (SPU). The AgNWs layer forms an interconnected conductive network that effectively reflects and absorbs electromagnetic radiation, providing efficient EMI shielding. The SPU layers contribute autonomous healing of mechanical damages and restoring structural integrity and conductive pathways. The composite films exhibit remarkable EMI shielding effectiveness (SE) (up to 64.6 dB), exceptional mechanical toughness (106.4 MJ/m3), and self‐healing capabilities, outperforming conventional shielding materials. The synergy between AgNWs and SPU layers offers lightweight, flexible, tough, and self‐healing properties, making this material highly promising for applications in wearable electronics, aerospace, and automotive industries where durability and long‐term reliability are critical. Highlights: Facile fabrication of sandwiched AgNWs layer between SPU films.Sandwiched AgNWs/SPU films with exceptional EMI shielding.AgNWs form conductive networks for efficient EMI shielding.Remarkable mechanical toughness of 106.4 MJ/m3 and self‐healing capability.Potential shielding materials for lightweight, wearable electronics, aerospace. [ABSTRACT FROM AUTHOR]

Highlights This study investigates novel polymer composites for enhanced thermal conductivity and electromagnetic interference (EMI) shielding. By incorporating sodium alginate‐mediated Ca crosslinked MXene and boron nitride fillers into an epoxy matrix, the composites exhibit significantly improved thermal, electrical, and mechanical properties. Surface treatment enhanced filler dispersion and interfacial bonding by introducing hydroxyl groups, which improve compatibility between the fillers and the matrix, thereby reducing agglomeration and creating robust thermal and electrical conduction networks. Hot‐pressing method further increases composite density by eliminating internal voids and aligning the fillers more effectively, resulting in superior characteristics. The best performing hot‐pressed composite achieved a through‐plane thermal conductivity of 7.45 W/m K, excellent EMI shielding effectiveness of 58.3 dB, along with a tensile strength of 37.2 MPa and an elongation as high as 3.8%. These enhancements make the composites highly suitable for advanced electronic devices where efficient heat dissipation and EMI shielding are critical. Surface treatment improves filler dispersion and compatibility. High‐filler composites are fabricated by hot‐pressing method. MX‐CA‐BN/EPH composites achieve 7.45 W/m K thermal conductivity. Enhanced EMI shielding effectiveness of 58.3 dB. [ABSTRACT FROM AUTHOR]

Most low infrared emissivity coatings for anti‐infrared reconnaissance are merely suitable for targets warmer than their surroundings, and their flexibility and wearability are unsatisfactory for dynamic stealth applications. Herein, a spectral‐selective and adjustable patterned polydimethylsiloxane/MXene/nanoporous polytetrafluoroethylene metafabric with an asymmetric structure is designed, which achieves spectral selectivity of reflection/emission in mid‐infrared wavebands and synchronous reflection/absorption of solar light, integrating "shielded infrared stealth" and "compensatory thermal camouflage" in temperature‐change scenarios. By synergizing the low infrared emissivity of MXene and the effective heat‐transfer suppression of the patterned polydimethylsiloxane, the metafabric obtains an infrared emissivity of as low as ≈28% and minimizes the radiative temperature difference between a target of 36 °C and its low‐temperature surroundings even to 2.5 °C. Conversely, the metafabric adaptively unitizes its surface infrared signature with its high‐temperature background via the thermal energy compensation supplied by the solar‐thermal/electrothermal conversion of MXene and the powerful radiation emission of the outer polydimethylsiloxane. Besides, the metafabric creates a comfortable skin‐interface microclimate by the high solar‐light reflection of the nanoporous polytetrafluoroethylene and exhibits satisfactory electromagnetic interference shielding performances, mechanical flexibility, self‐cleaning, and antioxidation. This work provides a new strategy for designing multifunctional thermal camouflage materials for counter‐reconnaissance in changeable surroundings. [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]

In this paper, the study of the homogeneous resistivity and two‐layer soil influences on the performance of the electrodes of grounding systems subjected to lightning strikes is carried out considering soil ionization. The study is done on the behaviour of the ground electrodes while the resistivity of the soil is altered from small to high value in the case of homogeneous soil, while the study is obtained on two‐layer soils in the case of diverse values of the reflection factor. In the suggested algorithm for two‐layer soils, each layer has its resistivity and dielectric constant, where the dielectric constant and soil resistivity depend on the lightning frequency. The field resulting from lightning strikes, which causes soil ionization, has been studied, and the results have been used to understand the behaviour of ground rods under the influence of lightning strikes. The credibility of the results has been strengthened by comparing it with what others have obtained recently. The article's novelty can be summarized in the investigation of the performance of the electrodes of grounding grids that are installed in high soil resistivity of uniform and two‐layer soils containing the impacts of soil ionization, lightning frequency, soil resistivity, and permittivity variations. [ABSTRACT FROM AUTHOR]

This manuscript addresses the issue of electromagnetic radiation interference experienced by secondary equipment in ultra-high voltage (UHV) fixed series capacitors (FSCs) under electromagnetic transient overvoltage conditions, which cannot be easily determined. To tackle this, a simulation and analysis method for the electromagnetic interference characteristics of secondary equipment is proposed. First, a primary system simulation model of UHV FSC is established, including modeling the platform's multi-conductor system. The electromagnetic transient overvoltage signals between the low-voltage busbar and the high-potential platform are then simulated and analyzed under two conditions: spark gap triggering and disconnector operation. Next, a finite element model of secondary equipment is created to simulate and analyze the electric field distribution of different materials in the area of the measuring box. The shielding effectiveness of the measuring box is calculated using the overvoltage signals at the measuring box location as excitation. This method allows for the simulation of the electric field distribution in the measuring box area for different materials and calculates the shielding efficiency of the measuring box. It effectively simulates the complex electromagnetic environment of secondary equipment, assesses the electromagnetic shielding efficiency of the measuring box, and provides a theoretical basis for analyzing and improving the anti-interference characteristics of the measuring box. [ABSTRACT FROM AUTHOR]

The growth of the Internet of Things has focused attention on visualized sensors as a key technology. However, it remains challenging to achieve high sensing accuracy and self-power ability. Here, we propose a self-powered visualized tactile-acoustic sensor (SVTAS) based on an elaborated triboelectrification-induced electroluminescence (TIEL) unit. To date, it features a high brightness of 0.5 mW cm-2 (32 cd m-2) and a record-low detection limit of 0.5 kPa in horizontal-sliding mode. Meanwhile, the SVTAS is applicable to convert acoustic waves into TIEL signals in contact-separation mode, showing the highest response to the 44.07 Hz sound, a high signal-to-noise ratio of 8.7 dB-1, and an ultrafast response time of 0.8 ms. Furthermore, advanced artificial visualized perception systems are constructed with excellent performance in recognizing motion trajectories and human speech with different words/sentences. This work paves the way for the highly efficient and sustainable development of new-generation self-powered visualized perception systems, contributing a solution to wireless communication free from electromagnetic interference. [ABSTRACT FROM AUTHOR]

The development of multifunctional electromagnetic interference (EMI) shielding materials with low cost, stable performance and mass production is still facing great challenges. High-density traditional metals limit the application of EMI shielding materials. The unique structure of wood is considered an effective way to solve the above-mentioned problems. In this study, waste wood was used as raw material to prepare low-energy metallized particleboard. The particleboard was functionally finished to show excellent hydrophobic properties and been used stably in a humid environment. Dynamic thermal mechanical properties and mechanical properties analyses of particleboard were carried out. The bend strength (MOR), elastic modulus (MOE) and tensile strength were 30.50 MPa, 5384 MPa and 7.85 MPa, respectively. Metallized particleboard exhibited excellent electromagnetic shielding effectiveness (EMI SE) (average value 81.62 dB) in the entire X-band. The preparation of wood-based shielding metallized particleboard provides a feasible strategy for replacing traditional metal materials. [ABSTRACT FROM AUTHOR]

In this study, ultra‐thin films of Al, Co, and multilayered Al/Co were fabricated using the magnetron sputtering technique on a very thin glass substrate. Subsequently, electromagnetic wave shielding measurements were conducted utilizing the transmission‐reflection line method with the aid of a vector network analyzer. In measurements conducted within the X‐band microwave frequency range within the waveguide, the maximum electromagnetic interference shielding effectiveness (EMI SE) values obtained were determined as 46 dB for Al, 24 dB for Co, and 48 dB for the multilayered Al/Co film. The structural and morphological analyses of these shielding films were included in the study using x‐ray Diffraction (XRD), energy dispersive x‐ray analysis (EDAX), Scanning Electron Microscopy (SEM), and Atomic Force Microscopy (AFM) techniques. Scattering parameter results indicated that increasing conductivity values enhance the shielding effectiveness (SE) while also demonstrating an additional positive impact on the SE value for multilayered structures. This finding indicates that nanometer‐thick Al or Al/Co multilayer films could significantly protect electronic devices or individuals exposed to X‐band microwave radiation. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

To provide a hold‐up time function in DC‐DC supplies for cell site stations or data centers, using a boost converter with a bulk output capacitor as a front‐end converter stage is a simple and highly cost‐effective solution. However, conventional boost converters with a hard‐switching operation result in low conversion efficiency and increased electromagnetic interference emissions. In this paper, a boost converter with a new non‐dissipative snubber is proposed that only requires two additional diodes, an inductor, and a multilayer ceramic capacitor. The main feature of the proposed snubber is that the components are not located on the main power processing path. This means they only require low ratings, improving cost‐effectiveness. A prototype converter is analyzed, realized, and applied to a 300 W redundant DC‐DC power supply module for a 5G cell base station. © 2024 The Author(s). IEEJ Transactions on Electrical and Electronic Engineering published by Institute of Electrical Engineers of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

In this paper, the effect of crosstalk noise in a mutually coupled multiwalled carbon nanotube (MWCNT) interconnect were investigated. The multiresolution time-domain method (MRTD) is used to analyze the crosstalk noise model. On the victim line of MWCNT interconnects, the worst-case propagation delay and peak voltage have been measured and compared to those obtained using the conventional finite difference time domain (FDTD) method, and HSPICE simulations for the 22 nm technology node have been validated. The results of the proposed method shows that the crosstalk induced propagation delays in both dynamic in-phase, out-phase, and peak voltage timing and peak voltage in functional crosstalk of the MWCNT interconnects are an average error less than 2% for the proposed model and conventional FDTD model with HSPICE simulations. It has been observed that the simulation results of the proposed model match accurately with HSPICE and dominate the conventional FDTD model. For various cases of input switching, the proposed numerical model is extremely time efficient and effective in evaluating crosstalk mediated propagation delay and peak voltages. The suggested approach could also be used to fix problems including electromagnetic interference and on-chip interconnect reliability. [ABSTRACT FROM AUTHOR]

Introduction. The presence of broad-spectrum and high-amplitude electromagnetic interference (EMI) within a single-phase induction motor (SPIM) drive poses a significant threat to both the system and other electronic equipment. High-frequency (HF) models of electrical motors play a critical role in overcoming these challenges, as they are essential for characterizing electromagnetic compatibility (EMC) in drives and designing effective EMI filters. The novelty of this study proposes an enhanced HF motor model based on transfer functions (TFs) to accurately represent the motor’s behavior at HFs for frequency-domain analyses in the range of 100 Hz to 30 MHz. Purpose. The equivalent HF model for a SPIM is discussed in this paper. The suggested equivalent circuit describes a motor’s common-mode (CM) properties. Methodology. HF model was developed by a frequency-domain analysis utilizing an experimental setup and MATLAB software. The motor impedance analysis is based on the measurement of variations in motor characteristics as a function of frequency in the CM setup. Originality. TF has been tuned using an asymptotic identification method of Bode to match the behavior of the real impedances of the motor parameters as a function of the frequency in the CM configuration. This tuned TFs are then synthesized into a comprehensive wideband EMC equivalent circuit model using the Foster network technique, which can be then simulated in any Spice-based simulator tools. Results. The proposed mathematical model was employed to conduct simulations, and the resulting predictions were validated against experimental data. CM response of the EMC equivalent circuit at low, medium, and HFs were compared between simulations and experimental measurements using Lt-Spice simulator software. Practical value. It is observed that results show satisfactory agreement with the measurements over a large frequency bandwidth [100 Hz–30 MHz], and the equivalent model of SPIM can be cascaded with other electronic and electrical modules to form a complete single-phase electric drive system model for fast analysis and prediction of system level EMI and electromagnetic sensitivity. [ABSTRACT FROM AUTHOR]

The design and development of efficient microwave-absorbing and electromagnetic interference (EMI) shielding materials and structures to conceal electromagnetic (EM) waves remains a consistent and challenging task. Despite advancements in materials science and microwave engineering, there is a need for optimized materials that offer both effective microwave absorption and EMI shielding while minimizing material layer thickness. This research aims to address this gap by utilizing the firefly algorithm (FFA) to predict the optimal medium properties and thickness of microwave-absorbing and EMI shielding materials under specific constraints. In this context, a comprehensive investigation was carried out at the X-band involving numerical and experimental EM characterization of novel lightweight fiber-based samples. Additionally, the FFA has been applied to optimize these fiber-based microwave structures within the given constraints. Two separate objective functions (OBF) targeting minimum sample thickness, maximum microwave absorption, and shielding effectiveness (SE) bandwidth have been integrated into the FFA to address the thickness–bandwidth trade-off issue. Subsequently, resistive ink-coated glass fiber (IGF) and ink-coated mesh fiber (IMF) were developed and characterized based on the optimal solutions provided by the FFA. Consequently, an optimized IMF sample provides a minimum reflection coefficient (RC) of −19.0 dB at 10.7 GHz with a bandwidth of 2.8 GHz (9.6 to 12.4 GHz) below the −10 dB threshold. Besides, the optimal IGF sample achieves maximum SE of 11 dB at thickness of only 0.8 mm and covers the entire operating band. Furthermore, the response of the proposed structure was assessed for various oblique angles of incidence, revealing significant potential for various practical applications. A strong correlation between measured and theoretical findings underscores the potential of the proposed approach in realizing efficient microwave stealth and EMI shielding materials. [ABSTRACT FROM AUTHOR]

Highlights: The large-scale, high-strength, super-tough, and multifunctional nacre-like heterocyclic aramid (HA)/MXene@polypyrrole (PPy) (HMP) nanocomposite papers were fabricated using the in-situ assembly of PPy onto the HA/MXene hydrogel template. The "brick-and-mortar" layered structure and abundant hydrogen-bonding interactions among MXene, PPy, and HA respond cooperatively to external stress and effectively increase the mechanical properties of HMP nanocomposite papers. The templating effect from HA/MXene was utilized to guide the assembly of conducting polymers, leading to high electrical conductivity and outstanding electromagnetic interference shielding performance. Robust, ultra-flexible, and multifunctional MXene-based electromagnetic interference (EMI) shielding nanocomposite films exhibit enormous potential for applications in artificial intelligence, wireless telecommunication, and portable/wearable electronic equipment. In this work, a nacre-inspired multifunctional heterocyclic aramid (HA)/MXene@polypyrrole (PPy) (HMP) nanocomposite paper with large-scale, high strength, super toughness, and excellent tolerance to complex conditions is fabricated through the strategy of HA/MXene hydrogel template-assisted in-situ assembly of PPy. Benefiting from the "brick-and-mortar" layered structure and the strong hydrogen-bonding interactions among MXene, HA, and PPy, the paper exhibits remarkable mechanical performances, including high tensile strength (309.7 MPa), outstanding toughness (57.6 MJ m−3), exceptional foldability, and structural stability against ultrasonication. By using the template effect of HA/MXene to guide the assembly of conductive polymers, the synthesized paper obtains excellent electronic conductivity. More importantly, the highly continuous conductive path enables the nanocomposite paper to achieve a splendid EMI shielding effectiveness (EMI SE) of 54.1 dB at an ultra-thin thickness (25.4 μm) and a high specific EMI SE of 17,204.7 dB cm2 g−1. In addition, the papers also have excellent applications in electromagnetic protection, electro-/photothermal de-icing, thermal therapy, and fire safety. These findings broaden the ideas for developing high-performance and multifunctional MXene-based films with enormous application potential in EMI shielding and thermal management. [ABSTRACT FROM AUTHOR]

Highlights: Unique inter-skeleton conductive films are constructed in polymer foam. The resistance change of the foam can reach four orders of magnitude under compression. This foam exhibits strain-adaptive electromagnetic interference shielding performance, anti-interference pressure sensor with high sensitivity over a wide pressure range and compression-regulated Joule heating function. Conductive polymer foam (CPF) with excellent compressibility and variable resistance has promising applications in electromagnetic interference (EMI) shielding and other integrated functions for wearable electronics. However, its insufficient change amplitude of resistance with compressive strain generally leads to a degradation of shielding performance during deformation. Here, an innovative loading strategy of conductive materials on polymer foam is proposed to significantly increase the contact probability and contact area of conductive components under compression. Unique inter-skeleton conductive films are constructed by loading alginate-decorated magnetic liquid metal on the polymethacrylate films hanged between the foam skeleton (denoted as AMLM-PM foam). Traditional point contact between conductive skeletons under compression is upgraded to planar contact between conductive films. Therefore, the resistance change of AMLM-PM reaches four orders of magnitude under compression. Moreover, the inter-skeleton conductive films can improve the mechanical strength of foam, prevent the leakage of liquid metal and increase the scattering area of EM wave. AMLM-PM foam has strain-adaptive EMI shielding performance and shows compression-enhanced shielding effectiveness, solving the problem of traditional CPFs upon compression. The upgrade of resistance response also enables foam to achieve sensitive pressure sensing over a wide pressure range and compression-regulated Joule heating function. [ABSTRACT FROM AUTHOR]

Interfacial jamming and assembly, facilitated by nanoparticle surfactant (NPS) complexation, demonstrate a remarkable efficacy in stabilizing multiphase systems, evident in structured liquid streams and structured Pickering emulsions. However, the utilization of structured liquid templates to tune multiple porosity levels of ultra‐flyweight aerogels is barely discussed. In this study, a structured Pickering emulsion is prepared through mixing an aqueous dispersion of graphene oxide (GO) with an organic (hexane) solution containing an active ligand. The emulsion is jetted into the same organic phase, resulting in "dual jamming". This process produced worm‐like aerogels with porosity that can be precisely tailored at four different levels: i) voids between filaments, ii) cavities produced by evaporation of trapped hexane droplets, iii) pores generated from sublimation of water in the bulk of GO emulsion, and iv) microscopic regions trapped between GO flakes or fractures/holes within GO nanosheets. These aerogels exhibit ultra‐low density (1.67–2.3 mg cm−3), high compressibility, and shape recovery. The multi‐scale porosity, created by structural design, endows aerogels with a record‐level fluid sorption capacity (e.g., 615 g g−1 for chloroform). Additionally, the aerogels demonstrate an absorption‐dominant electromagnetic interference (EMI) shielding mechanism, achieving a remarkable specific EMI shielding (SSE/t) of 67 178 dB cm2 g−1. [ABSTRACT FROM AUTHOR]

Background: The safety of new‐generation mobile phones using 5G networks in patients with modern‐generation pacemakers has not been studied. Objectives: This study aimed to compare the risk of electromagnetic interference (EMI) generated by a new‐generation mobile phone with 5G networks when positioned at the pacemaker pocket or the contralateral ear and assess the incidence of EMI with telemetry interrogation in patients with permanent pacemakers. Methods: We enrolled 489 patients with pacemakers from three different manufacturers. The pacemaker mode was programmed for overdrive pacing and sensing mode if an intrinsic rhythm was present. A smartphone (Samsung S21 + 5G) was placed directly over the pulse generator and right ear. The phone was tested under standby mode, 5G internet connection, and incoming and outgoing calls for each location. Real‐time electrocardiography (ECG) monitoring and patient symptoms were recorded to determine the occurrence of EMI. The possibility of EMI with interrogation telemetry was also investigated. Results: A total of 4824 tests were performed on 489 patients. Most pacemakers were dual‐chamber (82%) or magnetic resonance imaging (MRI)‐compatible systems (83%). EMI was not detected with both mobile phone positions. Interference with telemetry was demonstrated in 11.5% of patients. Almost all incidences of interference (98.2%) occurred during incoming calls. Single‐chamber pacemakers, non‐MRI‐compatible systems, older pulse generators, older leads, and unipolar settings were significantly related to a higher incidence of interference with interrogation telemetry. Conclusions: The risk of EMI between modern smartphones with 5G networks and pacemakers is low. Nevertheless, interference with the interrogation telemetry may still occur. [ABSTRACT FROM AUTHOR]

ABSTRACT In order to reduce the damage and interference caused by electromagnetic leakage to human beings and equipment during wireless energy transmission, this paper proposes a resonant hybrid array composite shielding structure based on an LCC‐S compensation circuit at an operating frequency of 200 kHz. First, by analyzing the effects of the number of turns and turn spacing on the coil coupling coefficient, the optimal parameters of the circular main coil were determined and analysis of the effect of different inductance ratios on the transmission efficiency of the system using MATLAB. Second, the system transmission efficiency and magnetic field distribution of the system with an intermediate resonant coil and three different types of array coils are simulated, and the optimal location of the hybrid array is determined; nanocrystals are selected as the shielding material and integrated reactive and passive shielding methods to improve system transmission performance and reduce electromagnetic leakage. Finally, an experimental platform was set up to verify the system's transmission performance. The results showed that when the hybrid array was placed in the center of the transmission coil, the magnetic flux density decreased by 40.1% at 58 mm from the measurement center. At a transmission distance of 16 mm, the transmission efficiency reached 60.2%, which was 9.4% higher than the situation without shielding. [ABSTRACT FROM AUTHOR]

Oriented aerogels, emerging as a new generation of lightweight electromagnetic interference (EMI) materials, often face complex synthesis processes. While creating an orderly oriented microstructure for EMI aerogels through ambient pressure drying (APD) shows promise, it remains a significant challenge. Here, inspired by the directional grown structure of the plant, a new strategy that employs rapid precursor orientation followed by slow cross‐linking to achieve the APD of directional EMI aerogels is proposed. This approach demonstrates that low‐temperature oriented polymerization of polyaniline enables strong cross‐linking with poly(3,4‐ethylenedioxythiophene) and alginate, forming a robust conductive directional skeleton and mitigating surface tension issues during mild drying. The resulting aerogel features high conductivity (48.84 S m−1), excellent flame retardancy, and impressive compressive strength. Notably, its sturdy frame allows for further enhancement with other functional materials, such as Mxene, through re‐processing and re‐drying. The tree‐branch‐like aerogel achieves a significantly improved EMI shielding effectiveness of 50.3 dB across an ultrawideband range of 8.2–40 GHz. This strategy offers a new idea for the straightforward preparation of functional aerogels with programmability and oriented microstructures using ambient drying. [ABSTRACT FROM AUTHOR]

The effects of electromagnetic (EM) radiation have received increased attention, closely associated with the widespread use of electronics and wireless communication. A significant development in the area is the recent adoption of metal‐organic frameworks (MOFs) to effectively enable electromagnetic interference (EMI) shielding. MOF tunable molecular scaffold architecture offers numerous pathways to generate customizable magnetic and electrical properties, which are prerequisite materials characteristics for efficient EMI shielding performance. Their flexibility in terms of structural design, accompanied by high porosity and large specific surface area, makes MOFs excellent candidates to shield EM waves at multiple scales. Herein, the crucial role of molecular‐, nano‐, micro‐, and macro‐scale structural design is reviewed in accordance with the shielding performance of MOFs. The current design strategies of MOF‐based EMI shields are systematically outlined, and the shielding mechanisms are also expounded based on their structural features. The factors that hinder the widespread utilization of functional MOF‐derived EMI shields are also examined. Future research directions are unveiled for the rational design of the next‐generation MOF‐based EMI shields to address the pressing EM radiation concerns. [ABSTRACT FROM AUTHOR]

Highlights In this novel work, we fabricated the multiwalled carbon nanotubes (MWCNTs)/polypyrrole (PPy) nanocomposite by employing the novel ultrasonic dual mixing (UDM) method. Subsequently, the atomistics and structural characterizations of the fabricated MWCNT/PPy nanocomposite (PM) were performed using SEM, Raman, and XRD. Furthermore, we experimentally evaluated the mechanical properties of the fabricated PM by reinforcing the PPy matrix with MWCNTs at different wt.%. The experimental study of PM shows that the mechanical properties depend upon the amount and dispersion quality of MWCNTs in the PPy matrix. In order to validate the experimental outcomes, the conservative fully coupled finite element (FE) models were developed using the ANSYS Workbench and novel FEAST software. The electromagnetic interference (EMI) shielding effectiveness (SE) of developed PM was also calculated at different thicknesses of PM by taking the effect of SE due to absorption (SEA) and SE reflection (SER) in the microwave frequency range of the C‐band (5.37–8.2 GHz) into consideration. The total SE (SET), the cumulative sum of SEA and SER, is the strong function of the thickness of the PM. Additionally, our study's outcomes reveal that as the thickness of the PM increased, the SET also increased by dominating the SEA rather than the SER. The SET value of 75 dB was observed for a sample with a thickness of 3 mm, indicating a high level of shielding. Thus, material becomes a highly attractive option for achieving high‐performance EMI SE in the C‐band for satellite communications, Wi‐Fi devices, weather radar systems, surveillance, and cordless telephones. A complex permittivity and permeability were also studied using the Nicolson–Ross–Weir (NRW) method to understand the mechanism behind the EMI SE. Nanocomposite fabricated using the novel ultrasonic dual mixing method. FE models were developed to validate experimental results. The EC and EMI SE are improved with the increase in the sample thickness. Absorption, rather than reflection, dominated the shielding mechanism. SE was observed ~75$$ \sim 75 $$ dB with good mechanical properties. [ABSTRACT FROM AUTHOR]

The electromagnetic interference shielding effectiveness (EMISE) and thermal conductivity (TC) of a graphene bio‐based epoxy composite were investigated in this study. This study aims to evaluate the effects of dispersion methods on the EMISE and TC of graphene bio‐based epoxy composites. Four dispersion methods were applied to disperse graphene: hand mixing, high‐shear mixing, ultrasonication, and ultrasonication with high‐shear mixing. The graphene weightage used in this study are 3, 6, and 9 wt.%. The EMISE was examined at the X‐band frequency. A microstructural analysis was performed using scanning electron microscopy to investigate the fracture surface morphology of the composites. The results revealed that the composite with 9 wt.% graphene exhibited the highest shielding effectiveness and TC, averaging 8.35 dB and 0.3855 W/mK, respectively, for all the dispersion methods. The composite with 3 wt.% graphene dispersed via ultrasonication exhibited the highest absorption loss (2.98 dB). Moreover, the composites with 6 and 9 wt.% graphene dispersed via ultrasonication with high‐shear mixing showed good overall improvement. This finding provides valuable insights into the effect of dispersion techniques on graphene bio‐based epoxy composites and presents a suitable dispersion method for improving the EMISE and TC. Highlights: Effect of dispersion methods on EMISE and TC has been investigated.Optimum SEA achieved in 3 wt.% composites dispersed via ultrasonication.Higher wt.% increased the SE and TC of composites.Ultrasonication with high‐shear mixing improved overall results. [ABSTRACT FROM AUTHOR]

Detecting buried active faults presents the challenge of precisely locating the upper breakpoint, the shallowest point in the Quaternary system where faults occur. Microtremor survey technology, unaffected by urban electromagnetic interference, offers an eco-friendly and efficient method for investigating buried faults and stratigraphic structures in urban areas. This research uses microtremor survey technology to identify the upper breakpoint of the buried Nankou-Sunhe Fault in Changping, Beijing. For data collection, 17 microtremor survey points were deployed across the northern section of the Nankou-Sunhe fault, employing a three-point nested circular array with a point spacing of approximately 200 m to form a profile spanning approximately 320 m. For data analysis, the spatial autocorrelation method was utilized. Each measurement point was divided into 9 sets of radii, ranging from a minimum of approximately 4 m to a maximum of 28 m. The correlation coefficients for each set were calculated, and the dispersion curve for each measurement point was generated by fitting the average coefficients with the Bessel function of the first kind of order zero. The apparent S-wave velocity was determined directly from the dispersion curve using empirical formulas and interpolated to generate the contour cross-section map. Integrating the section and inverted S-wave velocity data can significantly enhance interpretation accuracy, and based on these data, the spatial development characteristics and upper breakpoint locations of the Nankou-Sunhe fault zone were analyzed, and the strata shallower than 100 m were deduced. The results align well with known geological data, such as luminescence dating and 14C dating from boreholes at nearby locations. [ABSTRACT FROM AUTHOR]

Highlights The waste carbon fiber reinforced epoxy (WFRE) is difficult to recycle and high‐value reuse due to its irreversible cross‐linked structure. Currently, many recycling methods are flawed, rendering effective recycling unattainable and resulting in the waste of high‐value carbon fibers and increased environmental pollution. In this study, the production of high‐aspect‐ratio carbon fiber powder from WFRE was achieved through the application of solid‐state shear milling technology. The prepared EP/WFRE/CNT composites exhibited commendable mechanical properties and good electromagnetic interference (EMI SE) shielding efficiency, owing to the excellent dispersion and interfacial adhesion. The EMI SE value of EP/WFRE/CNT composites reached 21.9 dB, meeting the basic demand in the civil field. The flexural modulus of EP/WFRE/CNT composites reached 5914 MPa with the incorporation of 5 wt.% CNT. Moreover, the storage modulus of composite at 40°C increased from 2299 MPa for neat epoxy to 3006 MPa for composites. This research proposes a novel application of WFRE as good mechanical performance material for electromagnetic interference shielding, demonstrating the potential for commercial‐scale applications. Solid‐state shear milling can effectively peel epoxy resin. Solid‐state shear milling can preserve the high aspect ratio of carbon fiber. EP/WFRE/CNT has a flexural modulus of up to 5914.8 MPa. EP/WFRE/CNT has EMI SE that reaches 21.9 dB. CNT and carbon fiber synergistically formed conductive network. [ABSTRACT FROM AUTHOR]

Transparent electromagnetic interference (EMI) shielding is highly desired in specific visual scenes, but the challenge remains in balancing their EMI shielding effectiveness (SE) and optical transmittance. Herein, this study proposed a directionally aligned silver nanowire (AgNW) network construction strategy to address the requirement of high EMI SE and satisfactory light transmittance using a rotation spraying technique. The orientation distribution of AgNW is induced by centrifugal inertia force generated by a high‐speed rotating roller, which overcomes the issue of high contact resistance in random networks and achieves high conductivity even at low AgNW network density. Thus, the obtained transparent conductive film achieved a high light transmittance of 72.9% combined with a low sheet resistance of 4.5 Ω sq−1 and a desirable EMI SE value of 35.2 dB at X band, 38.9 dB in the K‐band, with the highest SE of 43.4 dB at 20.4 GHz. Simultaneously, the excellent conductivity endowed the film with outstanding Joule heating performance and defogging/deicing ability, ensuring the visual transparency of windows when shielding electromagnetic waves. Hence, this research presents a highly effective strategy for constructing an aligned AgNW network, offering a promising solution for enhancing the performance of optical‐electronic devices. [ABSTRACT FROM AUTHOR]

The development of next‐generation flexible electronics hinges on the creation of materials that are not only mechanically robust but also multifunctional. Herein, a novel approach is presented to fabricate an aramid nanofibers/cellulose nanocrystals/montmorillonite nanoplates (ACM) composite substrate with a robust "brick and mortar" microstructure. This substrate is seamlessly integrated with a high‐performance graphene/silver nanowire (G/Ag) composite conductive layer, resulting in the creation of ACM&G/Ag nanopapers. The resulting nanopapers achieve remarkable tensile strength (δc) (543.82 MPa), tensile modulus (Ec) (10.93 GPa), and toughness (Uc) (95.18 MJ m−3). Notably, when normalized by weight, the specific tensile strength of these nanopapers surpasses that of commercial titanium alloy, reaching 399.87 MPa g−1 cm3, compared to titanium alloy's 257.00 MPa g−1 cm3. With a high conductivity of 1398.08 S cm−1, ACM&G/Ag nanopapers exhibit impressive electromagnetic interference shielding effectiveness (EMI SE) of 39.59 dB and EMI SE/t of 16359.26 dB cm−1. Moreover, ACM&G/Ag nanopapers exhibit exceptional thermal management performance, featuring high electrical heating temperature (280 °C), rapid response time (<6 s), enduring heating stability, deicing capacity, and reliable heating performance even in humid environments. These results underscore the substantial potential of these high‐performance nanopapers in diverse applications such as wearable devices, electromagnetic compatibility, thermal management, human health, and aerospace. [ABSTRACT FROM AUTHOR]

Intrinsically stretchable conductors are vital components in next‐generation flexible electronics. However, solid conductive networks are generally vulnerable to external deformations due to their incompatible mechanical properties with the highly elastic substrates or matrixes. It is still challenging to achieve precisely controlled conductive structure with stable electromechanical performances. Herein, a nanocomposite conductor with 3D engineered bicontinuous phase system is developed, which is constructed by alternately arranged robust solid‐phase and conductive liquid‐phase via additive liquid/solid assembly. The proper rheological properties and extraordinary structural compatibility of the liquid‐phase prompt the formation of bridged structure within the 3D periodic solid‐phase main skeleton, giving rise to stable and even strain‐enhanced electrical and electromagnetic interference (EMI) shielding properties under external deformation. A negative resistance change of −37% along with unabated EMI shielding effectiveness and mechanical properties are obtained at 100% strain, showing negligible performance degradation even after 10,000 cycles of rigorous stretching and releasing. A strain‐tolerant pressure‐sensing device is further demonstrated using the liquid/solid nanocomposite structure, delivering a unique function of precisely recognizing the local pressure at large tensile loading interference. This work provides a new paradigm for the manufacturing of nanocomposites with desired functionalities using the adequate nanofiller reserve toward practical strain‐tolerant applications. [ABSTRACT FROM AUTHOR]

In this paper, a comparison of the emissions of grid-connected converters under grid distortion in the supraharmonic range is performed. The investigated supraharmonic grid distortion is divided into two types, namely odd-integer and even-integer multiples of the grid frequency. It is found that the first distortion type does not affect the emissions of the grid-connected converters, while the second distortion is responsible for the 2N-harmonic emissions that appear in the frequency spectra of the grid-connected converters, which, in turn, interact with the supraharmonic primary emissions of these converters, resulting in additional supraharmonic emissions. To explain this behavior, a mathematical analysis is provided for two types of grid-connected converters with an inverter interface and with a diode bridge rectifier interface. Simulations and experimental studies are performed to verify the main findings of the mathematical analysis. [ABSTRACT FROM AUTHOR]

The design and preparation of lightweight and flexible electromagnetic interference (EMI) shielding composites with high efficiency and low reflection are critical to the electronic field. First, silver nanowires (AgNWs) were vacuum filtered on the electrospun thermoplastic polyurethane (TPU) fibrous film. Then, by combining the adhesive with the electrospun silicon carbide nanowhisker (SiCnw) @TPU composite fibrous film, the asymmetric EMI shielding composite films with high electromagnetic shielding efficiency (EMI SE) and low incident power were obtained. The lower AgNWs‐TPU layer provides the primary EMI SE, and the upper SiCnw@TPU fibrous film is used for electromagnetic wave absorption. This unique asymmetric structure, the synergistic effect of SiCnw's particular absorbing function and the excellent conductivity of the AgNWs layer make the film show high overall SE (SET = 55.18 dB). In order to improve the absorption effect of the composite film, the number of layers of SiCnw@TPU was adjusted, resulting in a final reflection coefficient value as low as 0.55. This work proposes a new strategy for developing EMI shielding composite films with high efficiency and low reflection, serving as a reference. [ABSTRACT FROM AUTHOR]

Highlights: The introduction of MoS2 generates a "kill three birds with one stone" effect to the original binary MXene/ANF system: lubrication toughening mechanical performance; reduction in secondary reflection pollution of electromagnetic wave; and improvement in the performance of photothermal conversion. After the introduction of MoS2 into MXene/ANF (60:40), the strain and toughness were increased by 53.5% (from 18.3% to 28.1%) and 61.7% (from 8.9 to 14.5 MJ m−3), respectively. Fortunately, the SER decreases by 22.4%, and the photothermal conversion performance was increased by 22.2% from ~ 45 to ~ 55 °C. The design and fabrication of high toughness electromagnetic interference (EMI) shielding composite films with diminished reflection are an imperative task to solve electromagnetic pollution problem. Ternary MXene/ANF (aramid nanofibers)–MoS2 composite films with nacre-like layered structure here are fabricated after the introduction of MoS2 into binary MXene/ANF composite system. The introduction of MoS2 fulfills an impressive "kill three birds with one stone" improvement effect: lubrication toughening mechanical performance, reduction in secondary reflection pollution of electromagnetic wave, and improvement in the performance of photothermal conversion. After the introduction of MoS2 into binary MXene/ANF (mass ratio of 50:50), the strain to failure and tensile strength increase from 22.1 ± 1.7% and 105.7 ± 6.4 MPa and to 25.8 ± 0.7% and 167.3 ± 9.1 MPa, respectively. The toughness elevates from 13.0 ± 4.1 to 26.3 ± 0.8 MJ m−3 (~ 102.3%) simultaneously. And the reflection shielding effectiveness (SER) of MXene/ANF (mass ratio of 50:50) decreases ~ 10.8%. EMI shielding effectiveness (EMI SE) elevates to 41.0 dB (8.2–12.4 GHz); After the introduction of MoS2 into binary MXene/ANF (mass ratio of 60:40), the strain to failure increases from 18.3 ± 1.9% to 28.1 ± 0.7% (~ 53.5%), the SER decreases ~ 22.2%, and the corresponding EMI SE is 43.9 dB. The MoS2 also leads to a more efficient photothermal conversion performance (~ 45 to ~ 55 °C). Additionally, MXene/ANF–MoS2 composite films exhibit excellent electric heating performance, quick temperature elevation (15 s), excellent cycle stability (2, 2.5, and 3 V), and long-term stability (2520 s). Combining with excellent mechanical performance with high MXene content, electric heating performance, and photothermal conversion performance, EMI shielding ternary MXene/ANF–MoS2 composite films could be applied in many industrial areas. This work broadens how to achieve a balance between mechanical properties and versatility of composites in the case of high-function fillers. [ABSTRACT FROM AUTHOR]

The popularity of portable and wearable flexible electronic devices, coupled with the rapid advancements in military field, requires electromagnetic interference (EMI) shielding materials with lightweight, thin, and flexible characteristics, which are incomparable for traditional EMI shielding materials. The film materials can fulfill the above requirements, making them among the most promising EMI shielding materials for next‐generation electronic devices. Meticulously controlling structure of composite film materials while optimizing the electromagnetic parameters of the constructed components can effectively dissipate and transform electromagnetic wave energy. Herein, the review systematically outlines high‐performance EMI shielding composite films through structural design strategies, including homogeneous structure, layered structure, and porous structure. The attenuation mechanism of EMI shielding materials and the evaluation (Schelkunoff theory and calculation theory) of EMI shielding performance are introduced in detail. Moreover, the effect of structure attributes and electromagnetic properties of composite films on the EMI shielding performance is analyzed, while summarizing design criteria and elucidating the relevant EMI shielding mechanism. Finally, the future challenges and potential application prospects of EMI shielding composite films are prospected. This review provides crucial guidance for the construction of advanced EMI shielding films tailored for highly customized and personalized electronic devices in the future. [ABSTRACT FROM AUTHOR]

AbstractThermosets, before hardening, consist of independent macromolecules similar to thermoplastics, however, chemical curing of these macromolecules via heat or radiations may form irreversibly crosslinked macromolecular networks between their main chains. Graphene quantum dots are inimitable spherical nano-entities having the advantages of extremely small sizes, of 5-10 nm, very high surface area, surface/edge effects, quantum confinements and a range of physical characteristics including semiconductivity, fluorescence and magnetic properties. Similar to other nanocarbons (like graphene, fullerene or nanodiamonds), graphene quantum dots have been examined as noteworthy nanofillers to enhance the essential physical features of various macromolecular matrices, such as thermosets, thermoplastics and rubbers. Consequently, this review article was intended to systematically discuss the existing scientific state of graphene quantum dots reinforced thermosetting macromolecular matrices for the formation of high performance nanomaterials. According to the literature reports, the type, amount and molecular weight of these macromolecules seemed to affect the epoxy-quantum dots interactions and physical properties, like strength and heat stability of the resulting nanomaterials. Moreover, including graphene quantum dots in thermosetting matrices, like epoxies, hyperbranched polyesters and hyperbranched polyurethanes, has positively influenced the engineering aspects (mainly mechanical and thermal attributes) of the resulting nanocomposites owing to their interactions, compatibility and interfacial tendencies toward these matrices. Principally, epoxy/graphene quantum dots nanocomposites have been fabricated and investigated for the effects of graphene quantum nano-entities on the physical property enhancements of these irreversibly crosslinked macromolecules due to their mutual matrix-nanofiller interfaces. As per our analysis, the literature hitherto on the graphene quantum dots reinforced thermosetting matrix nanocomposites has disclosed significant property improvements of these macromolecules and their promising technological applications for high performance anticorrosion coatings, electromagnetic interference shields and biomedical fields. [ABSTRACT FROM AUTHOR]

The development of electronics and telecommunication technologies requires high‐performance electromagnetic interference (EMI) shielding materials to mitigate the rising concern of electromagnetic pollution. In this work, a novel partial dissolution approach is reported to fabricate an all‐natural eco‐friendly high‐strength cellulose/biochar (Cel@BC) composite showing excellent EMI shielding performance due to its densely crosslinking conductive core–shell structure. This results in a high conductivity of 130.9 S m−1, providing ultra‐high metal‐level EMI shielding effectiveness ≈72.4 dB. Absorption effectiveness reaches a maximum of 68.2 dB with electromagnetic waves absorbance >40%, featuring an obvious advantage over traditional reflecting‐dominated metals. This Cel@BC biocomposite presents lower environmental impacts than existing metals and petrochemical‐based plastics, as it biodegrades into carbon‐sequestering biochar. These outstanding EMI shielding properties and advantageous eco‐friendly nature make it an excellent cost‐efficient alternative to existing shielding materials on the market. [ABSTRACT FROM AUTHOR]

Silver nanofiber (Ag NF)-percolated networks have been widely utilized in the development of flexible transparent electrodes, transparent heaters, energy-saving devices, and electromagnetic interference shielding materials. Ag NFs with high aspect ratios substantially decrease the number density required for percolation, resulting in qualitatively superior transparent conducting networks. However, the mass production of Ag NFs with high aspect ratios is challenging. Recently, we developed a cost-effective method for the rapid mass production of Ag NFs that involves only two steps: blow spinning a self-reducing solution to generate precursor NFs, followed by heating treatment in air. However, the current utilization of high heating temperatures limits the choice of optional substrate materials. In this study, we investigate the effect of heating temperature on the self-reduction process and explore the possibility of lowering the heating temperature to rapidly produce Ag NFs. We observe that Ag NFs obtained at different heating temperatures exhibit similar microstructures, fiber diameters, compositions, and sheet resistances. In addition, we quantitatively analyze the self-reduction durations at different heating temperatures and examine the causes of failure of the self-reduction process at specific temperatures. The insights gained in lowering the heating temperature will contribute to broadening the range of suitable substrate materials and promoting energy conservation. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) fillers are a new hotspot in the development of polymer composites. The 3D microstructure is capable of effectively solving the agglomeration problem of low dimensional microstructure and forming 3D network in the polymer matrix at a very low percolation threshold. This could assist to transfer the charge carrier and heat as well as disperse the stress, further greatly improving the electrical conductivity, thermal conductivity, and mechanical properties of polymer composites. Starting from the different types of fillers, this review discusses the various methods including vapor deposition technology, template method, directional freezing method, and 3D printing technology for preparation of 3D carbon-based fillers, 3D inorganic fillers, and 3D organic-inorganic hybrid fillers in recent years, which will facilitate researchers to inspire the preparation of 3D fillers/polymer composites. Besides, this article also reviews the applications of 3D fillers/polymer composites in the fields of electronics and energy storage such as electromagnetic interference (EMI) shielding materials, thermally conductive materials, organic phase change materials, shape-memory materials, piezoresistive materials, and batteries as well as capacitors in detail. The relevant knowledge can boost researchers to fabricate the diverse 3D fillers/polymer composites and promote the development of related research on the 3D fillers/polymer composites. [ABSTRACT FROM AUTHOR]

Photonics-assisted methods for microwave frequency measurement (MFM) show great potential for overcoming electronic bottlenecks and offer promising applications in radar and communication due to their wide bandwidth and immunity to electromagnetic interference. In common photonics-assisted MFM methods, the frequency-to-time mapping (FTTM) method has the capability to measure various types of signals, but with a trade-off between measurement error, measurement range, and real-time performance, while the frequency-to-power mapping (FTPM) method offers low measurement error but faces great difficulty in measuring signal types other than single-tone signals. In this paper, a two-step high-precision MFM method based on the combination of FTTM and FTPM is proposed, which balances real-time performance with measurement precision and resolution compared with other similar works based on the FTTM method. By utilizing high-speed optical sweeping and an optical filter based on stimulated Brillouin scattering (SBS), FTTM is accomplished, enabling the rough identification of multiple different signals. Next, based on the results from the previous step, more precise measurement results can be calculated from several additional sampling points according to the FTPM principle. The demonstration system can perform optical sweeping at a speed of 20 GHz/μs in the measurement range of 1–18 GHz, with a measurement error of less than 10 MHz and a frequency resolution of 40 MHz. [ABSTRACT FROM AUTHOR]

A blood glucose concentration and temperature sensor with a balloon-shaped single-mode fiber (SMF) based on a core-offset structure is proposed and experimentally demonstrated. The balloon-shaped SMF is created by offset-fusing a straight-line SMF between two other SMFs, thereby forming a Mach–Zehnder interferometer (MZI). The core-offset structure can effectively excite higher-order cladding modes. The experimental results showed that the maximum sensitivity of blood glucose concentration was 0.331 nm/(mmol/l) and the maximum sensitivity of temperature was 0.216 nm/°C when the offset distance was 10 μm. Dual-parameter measurement was achieved through a dual-parameter matrix. In addition, the sensor has characteristics such as simple structure, low cost, good stability, and electromagnetic interference resistance, making it potentially valuable for diagnosing high blood glucose and related conditions. [ABSTRACT FROM AUTHOR]

The capability to identify the frequency of unknown microwave signals with an ultra‐wide measurement bandwidth is highly desirable in radar astronomy, satellite communication, and 6G networks. Compared to electronic solutions, the integrated photonic technology‐enabled dynamic instantaneous frequency measurement (DIFM) approach is attractive as it offers unique advantages, such as ultra‐wide frequency measurement bandwidth, high flexibility, and immunity to electromagnetic interference. However, so far the bandwidth of the reported DIFM systems based on integrated photonic technology is limited to below 30 GHz due to the finite bandwidth of electro‐optical modulators (EOMs), limiting their applications, particularly in the field of millimeter wave technology (30–300 GHz). Here, the first integrated dynamic microwave instantaneous frequency measurement system with a record‐breaking operation bandwidth (ranging from 5 to 65 GHz) and low root‐mean‐square (RMS) error (≈300 MHz) is presented on the lithium niobate on insulator (LNOI) integrated photonic platform. This demonstration paves the way for high‐performance millimeter wave photonic integrated devices using the LNOI platform. [ABSTRACT FROM AUTHOR]

This paper addresses and compares the modeling of typical EMI filters used in three-phase power equipment obtained through two different approaches, namely, physical and behavioral. Firstly, an innovative physical EMI filter modeling procedure is presented, which relies on an analytical formulation in terms of chain-parameters matrices and allows for an easy evaluation of its attenuation characteristics. The considered procedure builds an overall filter model by combining simple components models, requiring the determination of only a limited number of parasitic elements. Furthermore, the latter can be easily estimated without the need to build any prototype, avoiding the costly trial-and-error design procedures currently applied in the industrial context. Additionally, the considered physical model is tailored for high-power filters, built with thick wires, while most of the physical models available in the literature are aimed at small-sized filters built on printed circuit boards. The procedure is validated step by step, discussing the accuracy of each component model and its impact on overall accuracy compared to the actual measurements of the final assembled filter. Secondly, a behavioral modeling procedure is presented, which is based on external measurements performed on the filter prototype and provides an equivalent circuit model. Specifically, it extends to three-phase filters a circuit model previously developed for the single-phase case. Lastly, a critical comparison between the proposed physical and behavioral models is presented, highlighting the strengths and limitations of both and suggesting optimal uses for each. [ABSTRACT FROM AUTHOR]

The growing importance of electromagnetic interference (EMI) shielding composites in civil engineering has garnered increasing attention. Conductive cement-based composites, incorporating various conductive fillers, such as carbon nanotubes (CNTs), carbon fibers (CFs), and graphene nanoplatelets (GNPs), provide effective solutions due to their high electrical conductivity. While previous studies have primarily focused on improving the overall shielding effectiveness, this research emphasizes balancing the reflection and absorption properties. The experimental results demonstrate an EMI shielding performance exceeding 50 dB, revealing that filler size (nano, micro, or macro) and shape (platelet or fiber) significantly influence both reflection and absorption characteristics. Based on a comprehensive evaluation of the shielding properties, this study highlights the need to consider factors such as reflection versus absorption losses and filler shape or type when optimizing filler content to develop effective cement-based EMI shielding composites. [ABSTRACT FROM AUTHOR]

With the rapid development of bioscience and technology, wearable electronic devices are developing toward advanced trends such as flexibility, convenience, multifunctionality, and user‐friendliness. Herein, polystyrene‐block‐poly(ethylene‐co‐butylene)‐block‐polystyrene (SEBS) is employed for assisting the strong binding of silver nanoparticles (AgNPs) with polyimide nanofiber (PIF) to obtain the durable PIAgS conductive nanofiber membrane with antibacterial and hydrophobic ability. Owing to the porous fiber skeleton of nanofiber membrane and good interface adhesion, AgNPs can be homogeneously anchored onto fiber surface to construct stable and perfect 3D conductive network with an ultrahigh conductivity of up to 2102.7 S/m, enabling multifunctionality of the resultant conductive nanofiber membrane with superior bioelectric signal (EMG/ECG) sensing, pressure sensing (S = 1.45 kPa−1, 100 kPa) for deep learning assisted gesture recognition, electromagnetic interference (EMI) shielding (18757.8 dB·cm2·g−1), and electric heating (12.2 °C/V2) performances. Furthermore, as a multifunctional wearable electronic device, the antimicrobial ability of AgNPs and breathability of nanofiber membrane can ensure its sufficient wearing safety and comfort. Importantly, the inherent weathering resistance of PINF and SEBS also endows it with excellent stability and broad service life. Taken together, the designed conductive nanofiber membrane possesses great application potential for next‐generation multifunctional wearable electronic device with excellent stability and wide applicability. [ABSTRACT FROM AUTHOR]

It is demonstrated that single‐crystalline and highly doped GaAs membranes are excellent candidates for realizing infrared‐transparent shields of electromagnetic interference at millimeter frequencies. Measured optical transmittance spectra for the semiconductor membranes show resonant features between 750 and 2500 nm, with a 100% maximum transmittance. The shielding effectiveness of the membranes is extracted from measured scattering parameters between 65 and 85 GHz. Selected GaAs membranes and membranes/polyamide films exhibit shielding effectiveness ranging from 22 to 40 dB, which are suitable values to ensure the safe operation of infrared devices for commercial applications. Theoretical calculations based on a plane wave model show that the interplay of primary reflection and multiple internal reflections of the radio‐frequency waves results in broadband shielding capabilities of the membrane between 10 and 300 GHz. [ABSTRACT FROM AUTHOR]

The phase-shifted full-bridge converter is often used as an on-board DC/DC converter because of its advantages of easy control and low loss. The use of a spread spectrum modulation technique can reduce the conducted common mode electromagnetic interference. However, the spectrum expansion of periodic pulse width modulation is not strong enough and is accompanied by spectral overlapping phenomenon in the high-frequency band. In addition, the chaotic pulse width modulation generates a large number of low-frequency components and the spectrum expansion is not controllable. In this paper, discrete chaotic sequences are used to modulate the modulation frequency of the periodic function for the second time to enhance the harmonic side-band extension capability of the periodic pulse width modulation, and to solve the problem of the accumulation of the low-frequency harmonic components caused by the chaotic pulse width modulation, and the introduction of the wide-band characteristics of the chaotic sequences can alleviate the overlapping phenomenon of the spectrum in the high-frequency band. Through the whale optimization algorithm, the relevant modulation parameters affecting the periodic-chaotic pulse width modulation–modulation frequency fm and frequency extension range Δf are optimized. Finally, a 500W phase-shifted full-bridge converter experimental prototype verifies that period-chaos pulse-width modulation has better common mode EMI attenuation characteristics when compared with period pulse-width modulation and chaotic pulse-width modulation. In addition, it verifies the accuracy of the optimized parameters. The modulation means and optimization methods proposed in this paper can be used to reduce the conducted electromagnetic interference in switching power supplies. [ABSTRACT FROM AUTHOR]