Shielding Devices Research Articles

Highly Stretchable Supercapacitor‐Type Multifunctional Self‐Powered Porous Electronic Skins

AbstractThe development of highly stretchable self‐powered electronic skins with a broad detection range is urgently needed but remains a great challenge. Herein, unprecedented highly stretchable, broad‐range‐response, supercapacitor‐type, one‐body, and self‐powered electronic skins are developed by assembling porous polyurethane/polypyrrole electrode, polyacrylic acid/polyacrylamide ionic gel electrolyte, and porous polyurethane/MXene electrode. The folded porous structure of the electrodes significantly enhances the stretchability, while the modulus‐gradient multilayer structure of the device effectively broadens the pressure detection range. The electronic skins combine self‐powered dynamic/static pressure sensing, ultrabroad detection range (20 Pa–3.5 MPa), ultrahigh stretchability up to 387%, excellent compression stability (5000 cycles under 195 kPa), and good stretching stability (500 cycles under 200% tensile strain). They have the capability of monitoring human body motions, physiological signals, and high pressures from motorcycle tires, as well as tactile sensing of robotic grippers. In addition, they can be applied for highly stretchable thermal management and electromagnetic shielding devices. This work provides a new strategy for the development of highly stretchable, broad‐range‐response, and multifunctional self‐powered wearable electronics and sensors.

Highly durable and conductive Korea traditional paper (Hanji) embedded with Ti3C2Tx MXene for Hanji-based paper electronics

Lightweight, low-cost, eco-friendly, and mechanically flexible Ti3C2Tx (MXene) electrodes require for paper electronics. We develop a highly durable and conductive traditional Korean paper (Hanji) covered with MXene for Hanji-based paper electronics. The effective networking of MXene on the cellulose structure of Hanji leads to a highly conductive and flexible Hanji which acts as a multi-functional paper for Hanji-based paper electronics. Owing to the synergetic combination of Hanji and MXene, the as-prepared Hanji/MXene exhibits a low sheet resistance of 0.62 Ohm square−1, and outstanding mechanical stability without breaking the Hanji fibers. To further evaluate the potential of our Hanji/MXene composite, its performance in electromagnetic interference (EMI) shielding, interconnectors, heaters, supercapacitors, and temperature sensor applications is investigated. Shielding and heater paper samples employing Hanji/MXene-based electrodes show an EMI shielding efficiency (EMI SE) of 43.3 dB and saturation temperature of 76 °C at a low voltage of 3 V. Moreover, the Hanji/MXene-based supercapacitors exhibit a capacitance of 139.6 mF cm−2 at a current density of 1 mA cm−2. Furthermore, the Hanji/MXene-based temperature sensors exhibit an effective sensing performance over a wide temperature range. Overall, the successful operation of Hanji-based EMI shielding devices, interconnectors, heaters, supercapacitors, and temperature sensors indicates that Hanji/MXene serves as a promising conductive paper substrate for multi-functional paper electronics.

A Novel Shielding Device for Cardiac Cath Labs

Abstract This research evaluates the effectiveness of a large specialized cardiac catheterization laboratory shielding device (SCCLSD) placed perpendicular to the patient compared to traditional shielding methods in reducing occupational exposure to scattered x rays, contributing to the ongoing enhancement of radiation safety in the cardiac catheterization laboratory (CCL) setting. An experimental setup involving an anthropomorphic phantom on the catheterization table simulated radiation scatter from a patient. Measurements were taken systematically at various grid points and heights in the CCL using a Fluke 451P ion chamber while mimicking a real interventional scenario. In-air peak exposure rates were analyzed at head, chest, and waist heights in the anteroposterior (AP) position. Results demonstrated that the SCCLSD provided a superior radiation shadow and effective whole-body radiation exposure reduction compared to conventional shielding devices. Considering that conventional shielding requires staff to wear lead aprons, an effective dose equivalent correction factor was applied for exposure measurements without the SCCLSD. Even after the correction factor, the SCCLSD continued outperforming lead aprons and offered whole-body protection, including the head and arms, which is typically neglected with conventional shielding. The SCCLSD also reduces exposure to the eyes, aligning with lower occupational exposure recommendations from ICRP and NCRP. However, proper CCL staff positioning is important in maximizing the effectiveness of the SCCLSD. Future research avenues may explore exposure rates at different C-arm angles to more completely assess the SCCLSD’s impact on occupational exposure.

Percolation-Triggered Negative Permittivity in Nano Carbon Powder/Polyvinylidene Fluoride Composites.

Percolating composites exhibiting negative permittivity have garnered considerable attention due to their promising applications in the realm of electromagnetic shielding, innovative capacitance devices, coil-less inductors, etc. Nano carbon powder/polyvinylidene fluoride (CP/PVDF) percolating composites were fabricated that exhibit Drude-type negative-permittivity behavior upon reaching the CP percolation threshold. This phenomenon is attributed to the formation of a plasmonic state within the interconnected CP network, enabling the delocalization of electrons under the alternating electric field. Furthermore, a significant (nearly two orders of magnitude) increase in the conductivity of sample is observed at a CP content of 12.5 wt%. This abrupt change coincides with the percolation phenomenon, suggesting a transition in the conduction mechanism. To elucidate this behavior, comprehensive analyses of the phase composition, microstructure, AC conductivity, and relative permittivity were performed. Additionally, the sample containing 5 wt% CP exhibits a remarkably high permittivity of 31.5, accompanied by a relatively low dielectric loss (tanδ < 0.2). The findings expand the potential applications of PVDF, while the fabricated percolating composites hold promise for electromagnetic shielding, antennas, and other electromagnetic devices.

Modeling and Analysis of Magnetic Noise Characteristics of Permalloy–Nanocrystalline Magnetic Shielding Devices

Modeling and Analysis of Magnetic Noise Characteristics of Permalloy–Nanocrystalline Magnetic Shielding Devices

Analytical model and precise evaluation of multi-layer magnetic shielding performances considering ultra-weak magnetic properties

Regarding the vast difference between the design index and the actual performance of magnetic shielding devices, this paper proposes a novel method of using precise permeability under a specific weak magnetic field, aiming to improve the design accuracy of shielding performance. Firstly, the relative permeability of the permalloy is measured under the applied magnetic field from the geomagnetic field down to 1 nT. Next, the precise shielding coefficient formulas of the single- and double-layer spherical shells are derived. For the double-layer spherical shells, the deviation of remanence between considering the ultra-weak magnetic properties and using the constant permeability is 24.3%. This clarifies the necessity of considering the ultra-weak magnetic properties in multi-layer structures. Then, a new accurate method of the shielding coefficient for the finite-length magnetic shielding cylinder is proposed, with a deviation of less than 5%. Finally, this method has been validated again by remanence measurement of the three-layer magnetic shielding cylinders. The deviation between simulation and experiment is 4.03% when considering the ultra-weak magnetic properties. While using the constant permeability, the deviation is as high as 19.31%. Therefore, considering the ultra-weak magnetic properties in multi-layer structures can significantly improve the accuracy of the performance evaluation.

Research on the stress magnetic coupling effect of a permalloy based on an optimized Jiles Atherton model in magnetic shielding devices

Magnetic shielding devices are extensively used in the measurement of quantum physics, the static magnetic field shielding layer made of permalloy in the magnetic shielding device will work under different stresses. Due to the magnetic properties of permalloy being sensitive to the applied stress, it is necessary to establish a magnetic property model considering stress to accurately evaluate the residual magnetic field in magnetic shielding devices under different stresses. However, the measurement and modeling of the magnetic properties of permalloy under different stresses have not been considered in relevant research. In this paper, the magnetic properties of permalloy under different tensile and compressive stresses were measured, and the optimized Jiles Atherton (JA) model of permalloy considering stress constructed. The parameters of the JA model are extracted by a genetic algorithm,-the particle swarm optimization algorithm, through measurement. Finally, the effectiveness of the model in predicting magnetic properties is validated. The JA optimization model considering stress can improve the calculation accuracy of magnetic shielding devices, which is of great significance for the design and application of magnetic shielding devices.

The Effect of a Ferromagnetic Steel Enclosure on Magnetic Shielding Systems: Analysis, Modeling, and Experimental Validation

The Effect of a Ferromagnetic Steel Enclosure on Magnetic Shielding Systems: Analysis, Modeling, and Experimental Validation

Enhancement of Cobalt Bismuth Nano-Ferrite via Heat Treatment to be Applied in High-Frequency and Antimicrobial Applications

Cobalt bismuth nano-ferrite (Co/Bi) with the chemical formula CoBi0.02Fe1.98O4 was produced using a simple flash auto-combustion method at three different temperatures: as-prepared, 600°C, and 800°C. A single-phase spinel structure was confirmed using X-ray diffraction, and the nano-scale morphology was examined using AFM (atomic force microscopy). Magnetic measurements demonstrated that increasing the annealing temperature increased the saturation magnetization Ms by 1.3 times. However, the coercivity Hc changed from semi-hard ferrite (as-prepared sample) to soft ferrite (Co/Bi nano-ferrite at 800°C) and reduced 10.7 times that of as-prepared nanoparticles. Therefore, the 800°C Co/Bi nano-ferrite with a low coercive field is recommended for transformers, recording heads, inductor cores, magnetic shielding, and microwave devices. The as-prepared sample and that at 600°C displayed super-high microwave frequency (SHF) in the X band in high-frequency applications calculated from magnetic measurement. The 800°C sample also has an extremely high microwave frequency in the Ku band, which is utilized in radar and satellite communications. Antimicrobial characterization showed that raising the annealing temperature increased the effectiveness of the samples against tested microorganisms. Thus, the samples under investigation are highly suggested for ultra-high microwave frequency applications and biological antibacterial nanomaterials.

Multi-interfacial bridging engineering of flexible MXene film for efficient electromagnetic shielding and energy conversion

Accompanied by the progressive development of electronic equipment, excellent electromagnetic interference (EMI) shielding materials display a satisfying prospect in protecting electronic devices against electromagnetic pollution/radiation, while integrating energy conversion. Heretofore, it remains a conundrum to availably construct thin films with multi-interfacial bridging engineering as multifunctional shielding devices. To effectively achieve electromagnetic wave attenuation and integrate energy conversion, a co-mixed vacuum-assisted filtration strategy is designed to synthesize Au@MXene/cellulose nanocrystal/dodecylbenzenesulfonic acid-doped polyaniline (AMCP) films. Profited from the interfacial engineering, the total EMI shielding effectiveness (SE) can be increased by 27 % with the highest value of 67.9 dB. MXene with localized surface plasmon resonance characteristics gives the composite films good energy conversion performance, that is, the composite film can be rapidly heated up to 100 °C under the irradiation of an infrared lamp, and its surface temperature remains stable after continuous irradiation. Additionally, the infrared emissivity is as low as 0.173 within the 8–14 μm, which is necessary to adapt various application scenarios. Therefore, it is reliable that the AMCP films constructed by multicomponent offer a facile strategy for MXene-based EMI shielding devices with integration characteristics.

Analysis of comprehensive magnetic shielding and optimization design of high-conductive layers in magnetic shielding devices for atomic magnetometer

Since the frequency of the biological magnetic field is DC to 500 Hz, it is important to improve the ability of the magnetic shielding device within this range for the measurement of the biological magnetic field and the reduction of the magnetic noise of the SERF magnetometer. At present, the optimization of AC magnetic field shielding in the frequency range of 0.01 to 500 Hz is rarely considered. To optimize the AC shielding factor, this paper analyzed the influence of the position and structure of the high-conductive layer in the magnetic shielding device and proposed an optimized structure of the high conductive layer. What’s more, the theoretical formula was improved by introducing frequency coefficients, solving the problem of significant differences between theoretical calculation results, FEM results and measurement results. Finally, it was verified by experiments that the optimized high-conductivity layer structure can improve the AC shielding factor of magnetic shielding device.

MXene and AgNW based flexible transparent conductive films with sandwich structure for high-performance EMI shielding and electrical heaters

With the popularization of 5G technology and the development of science and technology, flexible and transparent conductive films (TCF) are increasingly used in the preparation of optoelectronic devices such as electromagnetic shielding devices, transparent flexible heaters, and solar cells. Silver nanowires (AgNW) are considered the best material for replacing indium tin oxide to prepare TCFs due to their excellent comprehensive properties. However, the loose overlap between AgNWs is a significant reason for the high resistance. This article investigates a sandwich structured conductive network composed of AgNW and Ti3C2Tx MXene for high-performance EMI shielding and transparent electrical heaters. Polyethylene pyrrolidone (PVP) solution was used to hydrophilic modify PET substrate, and then MXene, AgNW, and MXene were assembled layer by layer using spin coating method to form a TCF with a sandwich structure. One-dimensional AgNW is used to provide electron transfer channels and improve light penetration, while two-dimensional MXene nanosheets are used for welding AgNWs and adding additional conductive channels. The flexible TCF has excellent transmittance (85.1 % at 550 nm) and EMI shielding efficiency (27.1 dB). At the voltage of 5 V, the TCF used as a heater can reach 85.6 °C. This work offers an innovative approach to creating TCFs for the future generation.

3D Graphene Straintronics for Broadband Terahertz Modulation

AbstractThe increasing utilization of terahertz (THz) bandwidth in both industrial and private sectors highlights the significance of efficient terahertz shielding and absorption devices. These devices play a crucial role in safeguarding electronic components from disruptive effects and rendering objects less detectable by radar systems. However, the limited availability of materials and devices hinders progress in this field. In this study, a strain engineering route is presented for the active control of terahertz shielding and absorption properties in 3D graphene through the application of mechanical strain. A straintronic modulator based on 3D graphene is demonstrated, capable of modulating absorption and reflection of THz radiation in real‐time over a wide range of 0.1–3 THz. The modulator can be tuned to exhibit either shielding capability with a specific shielding effectiveness of 0.3 × 105 dB cm2 g−1 or stealth characteristics with an average reflection loss of 25 dB and 99.4% absorption. These findings open new avenues for leveraging 2D materials in their 3D porous form, where strain‐induced changes in interlayer interactions enable control over the properties of these materials. This discovery unveils vast unexplored physical phenomena with immense potential for advanced THz imaging, radar, and electromagnetic applications.

Enhancement of optical and radiation shielding properties in calcium–magnesium silicate bioactive glasses through Na2O and P2O5 additives

The present study investigates the influence of Na2O/MgO and P2O5/SiO2 substitutions on the structure and protective properties of bioactive glasses composed of 32CaO–19MgO–0.5P2O5–0.5CaF2–48SiO2 (mole %). The glass samples are prepared using the conventional melt-quenching method. Optical analyses, including refractive index (n), molar refraction (Rm), and cationic polarizability (αm), are calculated and discussed to examine structural modifications. Raman spectroscopy is employed for detailed structural analysis. The effects of compositional changes on the protective parameters are thoroughly investigated by theoretically determining mass attenuation using the newly developed Phy-X/PSD software and XCOM programs, which are then experimentally confirmed at three selected radioactive isotope energies. Experimental measurements of mass attenuation coefficient follow the sequence: MACG1 > MACG2 > MACG3 > MACG4. Raman spectroscopy results indicate that the glass network primarily consists of silicate and phosphate species as the main structural units. An increase in the molar ratio of Na2O and P2O5 improves the radiation shielding effectiveness of the samples. Among them, sample G5, with the lowest SiO2 and MgO content, exhibits the best shielding characteristics due to its high density and molar fraction of Na2O and P2O5. A correlation between microhardness and protective effectiveness is also established. The obtained results support the potential use of these glasses as dual agents for both radiation shielding and medical devices simultaneously.

Broad-wave reflection of polymer-stabilised cholesterol liquid crystal with nanofibers doped magnetic nanoparticles

ABSTRACT In this study, the polymer-stabilised cholesterol-based liquid crystal (PSCLC) films with broad-wave reflection were prepared via PVA nanofibers as carriers loaded with Fe3O4 nanoparticles. Fe3O4 nanoparticles have absorption properties in the UV region. When UV light is irradiated along the thickness of the liquid crystal cell, the resulting gradient distribution of UV light intensity induces a gradient distribution of spacing and thus a broad-wave reflection. Specifically, the effects of nanoparticles content loaded in nanofibers, magnetic field strength, polymerisation time and temperature, UV light intensity and polymerised monomer content were studied. The result shows that the proper contents of Fe3O4 nanoparticles and the polymerisation conditions have favourable impacts on the broad-wave reflection of PSCLC films. To clarify the mechanism of formed broad-wave reflection, the morphology of nanofibers was observed by scanning electron microscopy (SEM). The modification of nanoparticles was collected by transmission electron microscopy (TEM) and infrared spectroscopy. The texture of PSCLC films was observed by POM. The broad-wave reflection were measured by UV-Vis spectrophotometer. This strategy broadens the broad-wave reflection of PSCLC films from 300 nm to 476 nm increasing its application potential in UV shielding devices, and infrared thermal control devices.

Asymmetric and Flexible Ag-MXene/ANFs Composite Papers for Electromagnetic Shielding and Thermal Management.

Lightweight, flexible, and electrically conductive thin films with high electromagnetic interference (EMI) shielding effectiveness and excellent thermal management capability are ideal for portable and flexible electronic devices. Herein, the asymmetric and multilayered structure Ag-MXene/ANFs composite papers (AMAGM) were fabricated based on Ag-MXene hybrids and aramid nanofibers (ANFs) via a self-reduction and alternating vacuum-assisted filtration process. The resultant AMAGM composite papers exhibit high electrical conductivity of 248,120 S m-1, excellent mechanical properties with tensile strength of 124.21 MPa and fracture strain of 4.98%, superior EMI shielding effectiveness (62 dB), ultra-high EMI SE/t (11,923 dB cm2 g-1) and outstanding EMI SE reliability as high as 96.1% even after 5000 cycles of bending deformation benefiting from the unique structure and the 3D network at a thickness of 34 μm. Asymmetric structures play an important role in regulating reflection and absorption of electromagnetic waves. In addition, the multifunctional nanocomposite papers reveal outstanding thermal management performances such as ultrafast thermal response, high heating temperatures at low operation voltage, and high heating stability. The results indicate that the AMAGM composite papers have excellent potential for high-integration electromagnetic shielding, wearable electronics, artificial intelligence, and high-performance heating devices.

Highly efficient and stable Ra2LaNbO6 double perovskite for energy conversion device applications

Using first-principles calculations, in this piece of work, authors have investigated the physical properties of Ra2LaNbO6 double perovskite by employing the linearized augmented plane wave (LAPW) method. Structural and electronic properties are determined by using LDA, GGA (WC and PBE), LDA + mBJ, and GGA + mBJ potentials. We have found that Ra2LaNbO6 is an indirect band gap (Eg = 2.4 eV) semiconductor. Its elastic and thermodynamic parameters demonstrate its stability. Its optical study indicates that this material opens the door to its applications in optical devices such as photodetectors, solar cells, superlenses, optical fibers, filters, electromagnetic shielding devices, photovoltaic devices, etc. This material is very good for its practical implementation in thermoelectric devices as both p- and n-type material and extends the interest of experimentalists for further investigations. Thus, Ra2LaNbO6 is found thermodynamically stable and identified as a potential candidate for photovoltaic and thermoelectric devices.

Tough, stretchable dual-network liquid metal-based hydrogel toward high-performance intelligent on-off electromagnetic interference shielding, human motion detection and self-powered application

The stretchable conductive materials with adjustable electromagnetic interference (EMI) shielding performance and other multifunctional integrated applications are remarkably desirable and challenging in flexible electronics. However, the existing stretchable materials often suffer from the decay of EMI shielding performance during the stretching process, which limits their practical applications. Meanwhile, it remains a great challenge to construct materials with ordered porous frameworks as integrated shielding devices. Incorporating porous structure will generate abundant interior surfaces/interfaces, facilitating multiple reflections of incident electromagnetic waves (EMWs). Herein, we employ ultrasound method to modify liquid metal (LM) with carbon nanotubes (CNTs), and further utilize an UV in-situ polymerization method to fabricate CNT@LM/polyacrylamide/gelatin (LMCPG) dual network hydrogel elastomer. The LMCPG hydrogel elastomer possesses high strength and durability, and its tensile strength reaches 117 kPa at 1033% strain owing to the high strength of the rigid network and the beneficial deformation ability of the flexible network. Deformable CNT@LM droplets elongate randomly during stretching process, which facilitates establishing more conductive paths. The EMI shielding capacity of the stretched elastomer can be controlled, achieving an intelligent on-off behavior, which exhibits a 211% increase at 200% strain in EMI shielding effectiveness (SE) compared with the undeformed state. Moreover, the LMCPG elastomer shows a significant triboelectric performance, which can provide power supply for flexible electronic devices, achieving an uninterrupted monitoring of the human body motion by devices. Therefore, as a flexible electronic material, it can offer a facile solution to achieve intelligent multifunctional integrated EMI shielding materials.

Evaluation of Radiation Dose Reduction to Cardiologists by Tableside Shielding Devices

Evaluation of Radiation Dose Reduction to Cardiologists by Tableside Shielding Devices

Assembled MXene Macrostructures for Multifunctional Polymer Nanocomposites

As a thriving family of 2D nanomaterials, early transition metal carbides and carbonitrides (MXenes) are regarded as promising candidates in various applications. To enhance the mechanical robustness and environmental stability of MXenes, research on their polymer‐based nanocomposites with improved oxidation and damage tolerance has attracted increasing attention. As a reinforcing and functional filler, MXenes can also endow polymer with desired thermal/electrical properties. Compared to the powder‐based direct dispersion, assembling MXene nanosheets into MXene macrostructures (MMs) is proven as an effective strategy to unite with polymer. In particular, performance of the nanocomposites can be readily optimized by manipulating the structure of MMs and their interactions with polymer. In this Review, recent research progress on the MMs/polymer nanocomposites is summarized to provide a systematic understanding of the relationships among structures, fabrication techniques, and performance. Beyond diverse exfoliation methods for synthesizing MXene flakes, special attention is given to the assembly routes to construct mechanically robust macrostructures and hybrid techniques to build various MMs/polymer nanocomposites. Then, their applications in several areas of fundamental research and practical application are discussed, including heat/electrical conduction, electromagnetic shielding, and flexible devices. Finally, the challenges and perspectives are summarized to guide the future exploration for multifunctional MMs/polymer nanocomposites.