Search

[Display omitted] Covalent organic frameworks (COFs) are regarded as the potential and promising anode materials for potassium ion batteries (PIBs) on account of their robust and porous crystalline structure. In this work, multilayer structural COF connected by double functional groups, including imine and amidogent through a simple solvothermal process, have been successfully synthesized. The multilayer structure of COF can provide fast charge transfer and combine the merits of imine (the restraint of irreversible dissolution) and amidogent (the supply of more active sites). It presents superior potassium storage performance, including the high reversible capacity of 229.5 mAh g−1 at 0.2 A g−1 and outstanding cycling stability of 106.1 mAh g−1 at the high current density of 5.0 A g−1 after 2000 cycles, which is superior to the individual COF. The structural advantages of the covalent organic framework linking by double functional groups (d -COF) can develop a new road for that COF anode material for PIBs in further research. [ABSTRACT FROM AUTHOR]

It was found that the transfer film of SiO2/Polytetrafluoroethylene (PTFE) composite had terrace-like structure that affected the tribological properties in our previous work. Interestingly, the thickness of the different layers in this morphology was approximately equal, and the coverage rate of the different layers decreased with the increase of the number of layers. It is unknown whether this morphology exists in PTFE composites filled with other types of fillers. Especially, little is known about the influence of the different kinds of fillers on the morphology of the transfer film. In this paper, the effects of three different kinds of fillers, Polyetheretherketone (PEEK), WS2, and Si3N4, on the morphology of the transfer film were studied. The results showed that the transfer films of all the PTFE composites had terrace-like structure with a single layer of approximately the same thickness independent of the filler type. The effect of filler type on the number of layers was significant. The number of layers of the transfer film of PEEK/PTFE composite was the largest (4 layers) and that of WS2/PTFE composite was the smallest (1 layers). The wear resistance of the PTFE composites was independent of the monolayer thickness but increased with the number of layers. [ABSTRACT FROM AUTHOR]

The variable dielectric properties of multilayer structural ceramic/polyolefin composite film substrate materials with silicon dioxide (SiO2) and titanium dioxide (TiO2) powders as fillers and 1,2‐polybutadiene/styrene‐butadiene‐styrene triblock copolymer/ethylene‐propylene‐diene terpolymer/(1,2‐PB/SBS/EPDM) as polymer matrix were systematically investigated. Single‐layer SiO2, TiO2 and SiO2/TiO2/polyolefin‐based composite films denoted as A, B and H, respectively, were prepared by the flow casting method, and then multilayer structural composite substrates with different stacking methods were prepared by the hot pressing method. Four different layering modes were used: ABAB, AABB, ABBA, and BAAB. It was found that the dielectric constants of all four modes were within the scientific range. Compared to the other four types of laminated substrates, however, the fifth composite substrate with four identical film laminations made from a blend of two fillers (HHHH) exhibited better thermal stability and had a lower dielectric loss (0.00206) at 10 GHz compared to the other four types of laminated substrates. On the other hand, the other four types of laminated substrates have better mechanical properties compared to the hybrid substrates. This work provides a new idea for the preparation of oxide ceramic/polyolefin‐based dielectric composites that meet the requirements of different dielectric and thermomechanical properties. [ABSTRACT FROM AUTHOR]

The surface fracture toughness is an important mechanical parameter for studying the failure behavior of air plasma sprayed (APS) thermal barrier coatings (TBCs). As APS TBCs are typical multilayer porous ceramic materials, the direct applications of the traditional single edge notched beam (SENB) method that ignores those typical structural characters may cause errors. To measure the surface fracture toughness more accurately, the effects of multilayer and porous characters on the fracture toughness of APS TBCs should be considered. In this paper, a modified single edge V-notched beam (MSEVNB) method with typical structural characters is developed. According to the finite element analysis (FEA), the geometry factor of the multilayer structure is recalculated. Owing to the narrower V-notches, a more accurate critical fracture stress is obtained. Based on the Griffith energy balance, the reduction of the crack surface caused by micro-defects is corrected. The MSEVNB method can measure the surface fracture toughness more accurately than the SENB method. [ABSTRACT FROM AUTHOR]

Tungsten is one of best candidates for plasma facing materials (PFMs) in fusion reactors. But its application in fusion areas is strongly restricted by the inherent brittleness and high ductile–brittle transition temperature. To improve the toughness of W-based materials, W/TiN/Ta-laminated composites were fabricated by spark plasma sintering. Three-point bending test was performed to investigate the bending mechanical properties. Multiple crack propagation is the main crack propagation mode in W/TiN/Ta composites. Energy dissipation by interfacial debonding and crack deflection at interfaces as well as crack bridging by Ta foils and plastic deformation of Ta can contribute to the toughening of W/TiN/Ta composites. The existence of interfacial TiN coatings can act as weak points and promote interfacial debonding. TiN coatings with (111) preferred orientation are found to be conducive to the strengthening of W/TiN/Ta composites. [ABSTRACT FROM AUTHOR]

Flexible pressure sensors capable of monitoring diverse physiological signals and body movements have garnered tremendous attention in wearable electronic devices. Thereinto, high constant sensitivity over a wide pressure range combined with breathability, biocompatibility, and biodegradability is pivotal for manufacturing of reliable pressure sensors in practical sensing applications. In this work, inspired by the multilayered structure of skin epidermis, we propose and demonstrate a multi-attribute wearable piezoresistive pressure sensor consisting of multilayered gradient conductive poly(ε-caprolactone) nanofiber membranes composites. In response to externally applied pressure, a layer-by-layer current path is activated inside the multilayered membranes composites, leading to the most salient sensing performance of high constant sensitivity of 33.955 kPa−1 within the pressure range of 0–80 kPa. The proposed pressure sensor also exhibits a fast response—relaxation time, a low detection limit, and excellent stability, which can be successfully used to measure human physiological signals. Lastly, an integrated sensor array system that can locate objects' positions is constructed and applied to simulate sitting posture monitoring. These results indicate that the proposed pressure sensor holds great potential in health monitoring and wearable electronic devices. [ABSTRACT FROM AUTHOR]

In this study, the dynamic responses under blast loading of carbon fiber reinforced aluminum alloy laminates with different curvature radii, different numbers of layers, and different layer directions of carbon fiber under blast loading were compared numerically. The finite element models were built with ABAQUS/Explicit. To calibrate the numerical models, experiments on curved carbon fiber and curved aluminum alloy were modeled, and the numerical results showed good agreement with the experimental data. The calibrated numerical models were used to simulate the dynamic response of cylindrical panels subject to external explosion loading. The stiffness degradation coefficient was introduced to more accurately simulate the failure mode of the composite structures. The deformation and energy absorption of carbon fiber reinforced aluminum alloy laminates under different structural parameters were obtained. These simulation findings can guide the theoretical study and optimal design of carbon fiber reinforced structures subject to external blast loading. [ABSTRACT FROM AUTHOR]

Nanostructured Ti–Al–Mo–N and Ti–Al–Mo–Ni–N coatings with a layered architecture have been grown by arc PVD. We have determined deposition parameters (reaction gas (nitrogen) pressure and negative bias voltage applied to the substrate and determining the energy of incident particles) that enable the formation of a two-phase nitride (TiN + Mo2N) coating in the Ti–Al–Mo–N system and a nitride–metal (TiN + Mo2N + Ni) coating in the Ti–Al–Mo–Ni–N system. The addition of Ni to the composition of Ti–Al–Mo–N coatings leads to a decrease in the average grain size of the nitride phases from 35 to 12 nm and reduces the modulation period from 50 to 35 nm by limiting the growth of nitride nuclei. This is accompanied by a decrease in biaxial macrostress: from σ = –2.51 GPa in the Ti–Al–Mo–N coating to σ = –0.67 GPa in the Ti–Al–Mo–Ni–N coating. [ABSTRACT FROM AUTHOR]

The necessary conditions are established for the thicknesses of two layers of the planar absorbing structure at which zero reflectance can be achieved. Using these conditions, a numerical procedure was developed for finding the thicknesses of three layers of the structure, which makes it possible to achieve close to zero values of the reflectance and transmittance for the chosen wavelength. This made it possible to propose a method for designing narrow-band absorbers based on such structures. [ABSTRACT FROM AUTHOR]

We present a study of high efficient terahertz (THz) wave generation in DASB/GaAs, DASC/GaAs, and DAST/GaAs multilayer structures at 1.5THz via difference frequency generation (DFG) process with 1.5µm femtosecond laser pulses. We also compare the conversion efficiency in proposed structures with DASB/SiO2, DASC/SiO2, and DAST/SiO2 multilayer structures and bulk crystals DASB, DASC, and DAST. These structures compensate for phase mismatching in bulk crystals DASB, DASC, and DAST and increase conversion efficiency from 10-5 in bulk organic crystals up to 10-3 in multilayer structures. We show that DASC/GaAs is the best structure to generate 1.5THz waves.

Background. The most important stimulus for the study of piezoceramic materials is the increasing requirements for extending the operating temperature range, improving the measurement characteristics, and the stability to destabilizing factors of the devices created on their basis. However, along with a search for new promising materials and refinement of manufacturing technology to solve the above problems, the development of high-temperature textured materials for manufacturing multilayer piezoelectric transducer elements is becoming increasingly necessary. Materials and methods. Research methods were chosen based on the possibility of obtaining the most complete information about the change in the structure and properties of the material after sintering and polarization of products. When carrying out research, X-ray structural, radiographic, metallographic and electron-microscopic analyses were used. The measurements of mechanical and electrical strength, fracture resistance, dielectric permittivity, piezoelectric and segmented elastic characteristics of the products were carried out in the course of the work. Results. The technology of multilayer piezo packages production has been developed, the results of the technology of solid solution system piezoceramics production have been obtained, the structure, dielectric and piezoelectric properties of ceramics in the temperature range 20÷600 ℃ have been studied. Experimental samples of multilayer piezoelements were made.

High‐performance multilayer dielectric elastomer actuators (DEAs) are well‐positioned to overcome the insufficient output force and energy density as artificial muscles. However, due to the fabrication process, the multilayer DEAs with nonmodifiable structures often suffer from the limitation of short lifespans and scalable preparation. Herein, reusable multilayer DEAs with the detachable and reconfigurable structure are fabricated. This is achieved by realizing scalable compliant electrodes using the continuous spatial confining forced network assembly (CSNA) method and combining the vacuum lamination (VL) approach to have good attachability and detachability with the VHB dielectric elastomer. The flexible roller‐based CSNA method is used to prepare the large area compliant electrodes composed of α, ω‐dihydroxy polydimethylsiloxane and electrically conductive nanoparticles. The fabricated electrodes can continuously work over 10 000 cycles at 40% strained stretching and maintain smooth surfaces to construct multilayer DEAs. Moreover, owing to the detachable configuration of the DEAs, the electrodes can also be recovered and reused for building new actuators. The lower limb assistive device is demonstrated by detachable multilayer spring roll DEAs, achieving approximately 3.1 degrees of flexion and extension movement of knee models under a voltage of 7 kV. The detachable and reconfigurable multilayer DEAs shed new light on the applications of wearable assistive devices. [ABSTRACT FROM AUTHOR]

Interlaminar failure caused by scratches is a common damage mode in automotive coatings and is considered the potential trigger for irreversible destruction, i.e., plowing. This work strives to numerically investigate the mechanisms responsible for the complex scratch behavior of an automotive coating system, considering the interfacial failure. A finite element model is developed by incorporating a large deformation cohesive zone model for scratch-induced debonding simulation, where the mass scaling technique is utilized to minimize computational burden while ensuring accuracy. The delamination phenomenon of the automotive coating is reproduced, and its effects on scratch damage behavior are analyzed. Accordingly, it is revealed that the interlaminar delamination would produce significant stress redistribution, which leads to brittle and ductile damage of the coating and consequently affects the formation of plowing. Eventually, parametric studies on the effects of interfacial properties are performed. They demonstrate that the shear strength and shear fracture energy dominate scratch-induced delamination. [ABSTRACT FROM AUTHOR]

Despite being one of the oldest and most widely-used turbulence models in engineering computational fluid dynamics (CFD), the k-ω model has not been fully understood theoretically because of its high nonlinearity and complex model parameter setting. Here, a multi-layer analytic expression is postulated for two lengths (stress and kinetic energy lengths), yielding an analytic solution for the k-ω model equations in pipe flow. Approximate local balance equations are analyzed to determine the key parameters in the solution, which are shown to be rather close to the empirically-measured values from the numerical solution of the Wilcox k-ω model, and hence the analytic construction is fully validated. The results provide clear evidence that the k-ω model sets in it a multilayer structure, which is similar to but different, in some insignificant details, from the Navier-Stokes (N-S) turbulence. This finding explains why the k-ω model is so popular, especially in computing the near-wall flow. Finally, the analysis is extended to a newly-refined k-ω model called the structural ensemble dynamics (SED) k-ω model, showing that the SED k-ω model has improved the multi-layer structure in the outer flow but preserved the setting of the k-ω model in the inner region. [ABSTRACT FROM AUTHOR]

Pulsed eddy current (PEC) technology serves as a popular testing method for multilayer structures and is widely used in coating and substrate thickness measurement. However, in the coating thickness measurement of a multilayer structure, the substrate thickness effect is a disturbance that needs to be eliminated urgently. In order to reduce the substrate thickness effect, in this paper a twice difference normalisation method is proposed to obtain a signal feature independently of the substrate thickness effect for measuring the coating thickness of a multilayer ferromagnetic structure. The simulation and experimental results demonstrate that a fitting line of the peak value of twice difference normalisation signals can be obtained by using the twice difference normalisation method when only the coating thickness changes. The normalisation fitting line is immune to the substrate thickness effect and can be used to measure the coating thickness of a multilayer ferromagnetic structure, which means that the twice difference normalisation method is feasible for high-precision evaluation of the coating thickness of a multilayer ferromagnetic structure when the substrate thickness changes. This study will improve the coating thickness measurement accuracy of multilayer ferromagnetic structures when the substrate thickness changes in the PEC testing. [ABSTRACT FROM AUTHOR]

The leakage behavior of ferroelectric film has an important effect on energy storage characteristics. Understanding and controlling the leakage mechanism of ferroelectric film at different temperatures can effectively improve its wide-temperature storage performance. Here, the structures of a 1 mol% SiO2-doped BaZr0.35Ti0.65O3 (BZTS) layer sandwiched between two undoped BaZr0.35Ti0.65O3 (BZT35) layers was demonstrated, and the leakage mechanism was analyzed compared with BZT35 and BZTS single-layer film. It was found that interface-limited conduction of Schottky (S) emission and the Fowler-Nordheim (F-N) tunneling existing in BZT35 and BZTS films under high temperature and a high electric field are the main source of the increase of leakage current and the decrease of energy storage efficiency at high temperature. Only an ohmic conductive mechanism exists in the whole temperature range of BZT35/BZTS/BZT35(1:1:1) sandwich structure films, indicating that sandwich multilayer films can effectively simulate the occurrence of interface-limited conductive mechanisms and mention the energy storage characteristics under high temperature. [ABSTRACT FROM AUTHOR]

The interface of photovoltaic (PV) systems to the grid requires an efficient control strategy to operate, control, and improve power quality. The output voltage of the solar array, which may be accompanied by significant voltage variations, must be controlled and converted to a higher voltage for grid connection applications of photovoltaic system by a DC‐DC converter that commands more attention. Recently, due to the increasing use of renewable sources, multilayer structure with different structures and designs to provide power and stability has been researched because the output voltage of solar arrays is usually low, so it is increasing to DC‐to‐DC converters, needed with optimal interest and efficiency. In this paper, a method to improve the performance of DC–DC converter used in PV system by using a combined design of forward and fly‐back is presented. Due to the fact that isolated converters, flyback, and forward converters have a simple structure and are easy to control, but this converter is affected by high stress voltage. Therefore, this converter cannot be used for high power applications. To solve this problem, it has been improved in the proposed converter with the overlay and triple induction technique, which is a very good improvement on the voltage gain parameters in the short duty cycle. The voltage drop across the semiconductor switch is reduced. The investigations performed that the proposed DC/DC converter in Simulink MATLAB has been simulated. The results show that the suggested converter has an ideal efficiency of roughly 82.86% and provided higher voltage gain, decreased voltage stress, and reduced voltage jumps caused by disconnection. [ABSTRACT FROM AUTHOR]

In this study, lithium iron phosphate (LFP) is prepared as cathode material by hydrothermal synthesis method and the combined effect of doping and capping is applied to co-modify it. We thoroughly investigate how Zn2+ doping and PA capping layer affect the crystal structure, microscopic morphology, and electrochemical properties of LFP cathode materials. The experimental results show that when co-modified with 5 % Zn2+ doping combined with 7 % PA capping layer, the resulting cathode material exhibits a discharge specific capacity of 165.5 mAh g−1, and the capacity retention rate can still be maintained at a high level of 98.6 % after 200 charge–discharge cycles. [ABSTRACT FROM AUTHOR]

• The process parameters are determined through trial runs based on the bead height and width of single-bead geometry. • The grain boundary wetting transion (GBWT) is depicted by SEM image to identify incomplete and complete wetting transition. • A precipitation-hardened matrix has formed, resulting in reduced ductility in the top portion of the deposited sample. • The laves and δ phases of the deposited samples are investigated by SEM analysis, and the EBSD γ phase is identified. • The grain growth occurs when Ni elements are added to the laves and delta phases of the deposited samples. The current research work deals with the investigation of mechanical, wetting transition on grain boundary (GB) and metallurgical properties of Inconel 718 alloy used in aerospace industrial applications. The fabrication of thin-wall structure (multilayer structure) is fabricated using wire arc additive manufacturing (WAAM) technique. The novelty of this method is that gas metal arc welding (GMAW) is used as energy source and cold metal transfer (CMT) is used as mode of droplet transfer. Four tensile samples are extracted asper ASTM E8/E8M standards and three microstructure samples are extracted from thin wall structure. Optical microscopy (OM), SEM, EDAX, and EBSD analysis were carried out. In addition, Hardness and tensile tests, as well as fractography analysis were conducted. The grain boundary wetting transition (GBWT) analysis is also carried out. SEM analysis reveals that Nb-rich MC-type carbide contains grain boundaries of droplets, indicating incomplete wetting. Laves and delta (δ) phases are also identified as liquids of a continuous layer separated by Ni elements, indicating complete wetting. EBSD analysis indicates the average grain size as 251.2 μm. The average value of micro hardness as 417.3 HV and UTS as 609.75 MPa are achieved. [ABSTRACT FROM AUTHOR]

• C /Al composite with high EM shielding properties (75 dB) is prepared by a simple rolling process. • C/Al composite is ultralight (density ∼ 1.1 g/cm3). • C/Al composite is highly conductive (1.3 × 106 S/m, specific conductivity 1.13 × 103 Sm2/kg). • C/Al composite also demonstrates high mechanical property with the tensile strength of 95 MPa. In this report, we demonstrate a convenient method to successfully fabricate carbon/aluminium(C/Al) composites by creating a good interface between carbon nanotube (CNT) sheets and Al materials. To enhance the conductivity of carbon matrix, we employ physical and chemical compaction, together with gold-doping techniques to the carbon nanotube sheets. The morphology, structure and properties of C/Al composites are characterized by SEM, Raman spectrum, tensile test, and vector network analysis. The results show that the density of the successfully prepared composite is only 1.1 g/cm3. The tensile strength reaches 95 MPa. The conductivity can reach 1.3 × 106 S/m, and the specific conductivity is 1.13 × 103 Sm2/kg, and the electromagnetic (EM) shielding properties in the X-band (8.2–12.4 GHz) can reach 75 dB, which present fascinating aspect in the shielding application. [ABSTRACT FROM AUTHOR]

Optimization problems in real-world scenarios require algorithms that effectively balance exploration and exploitation to avoid local optima and achieve global solutions. To address this, we propose a unified artificial electric field algorithm (U-AEFA) that integrates both offline learning (inspired by high-performing metaheuristic algorithms) and online learning (through historical data generated during evolution). U-AEFA introduces a unique three-layer population structure to enhance search efficiency, consisting of the best agent in the first layer, the top-performing agents in the second layer, and the remaining agents in the third layer. Key features of U-AEFA include (i) an effective Coulomb's constant for improved exploration, (ii) a non-uniform mutation operator to mitigate premature convergence, and (iii) two acceleration coefficients for enhanced performance. These three factors constitute offline learning and have been implemented to improve different design elements of the algorithm. As part of online learning, it employs a difference vector reuse (DVR) strategy to evolve the first-layer agents. The algorithm is evaluated using the CEC 2017 test suite across multiple dimensions (10, 30, 50, 100), where it consistently outperforms seven state-of-the-art algorithms, demonstrating superior accuracy and convergence speed. Moreover, U-AEFA's robustness is validated on 12 high-dimensional feature selection problems, further highlighting its effectiveness in solving complex optimization tasks. The source code of U-AEFA is available at • Proposal of a three-layer hierarchical structure to facilitate the interaction of agents. • Use of difference vector reuse strategy to enhance the exploitation ability. • An effective Coulomb constant is incorporated to enhance exploration. • Introduction of a mutation operator to mitigate the issue of premature convergence. • Application on high-dimensional feature selection problems. [ABSTRACT FROM AUTHOR]

• The porous properties (size distribution) of claystone and cement mortar were analysed by NMR T 2 spectroscopy. • Three-dimensional pore matrix models of claystone and cement mortar were reconstructed based on CT identification techniques. • The pore matrix models reconstructed in 3D based on CT were accurately located and identified in the IIZ. The interfacial influence zone (IIZ) is a weak link between cast-in-situ cement materials and bulk geological materials. Identifying IIZ is essential for studying binary structure's mechanical properties. This paper aims to locate the IIZ of a clay rock-cement mortar (C-C) binary by macro-pore distribution in space using CT and NMR tests. First, the porous properties of clay rock and cement mortar were analyzed by the T 2 spectrum of the NMR test. Mortar's macro-pore volume is larger than clay rock's. Second, the 3D pore-matrix models of these two materials were reconstructed., with larger porosity in mortar than clay rock, consistent with NMR tests. Therefore, the method of pore location using 3D reconstructed models based on CT images may be reliable. Finally, a pore-matrix model of the C-C binary was reconstructed, and the IIZ was identified by pore distribution. The IIZ shape is an approximately ellipsoidal area with thin ends and thick middle, with a max thickness of 8 mm. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel Ag/G/Cu multilayer composite substrate was obtained by ultrasonic action. • Effect of graphene interlayer on the Raman signals of substrates was investigated. • The fabricated composite substrate shows high SERS sensitivity to R6G. Graphene-mediated surface-enhanced Raman scattering (SERS) substrates are currently being investigated for their potential in ultrasensitive detection. Graphene (G) combined with plasmonic metal nanostructures is expected to provide an exceptional SERS response. Here, we prepared a flexible multilayer composite structure by directly decorating silver nanoparticles (Ag NPs) on CVD graphene/copper foil under ultrasonic conditions. Due to the multi-dimensional plasmonic coupling of precious metals, extra chemical enhancement and exceptional molecule harvesting capability of G interlayer, the as-prepared Ag/G/Cu multilayer composite structure manifested ultrahigh sensitivity with the detection limit of Rhodamine 6G (R6G) as low as 1.0 × 10-14 M and a high enhancement factor (EF) of 8.86 × 108. The high performance flexible SERS substrate, with its ingenious process and simple structure, demonstrates excellent potential for applications in environmental protection. [ABSTRACT FROM AUTHOR]

• Various oxide precursors were used to coat SiO particles, which were then subjected to high-temperature sintering to form composites. • The oxide cladding has a good rigid shell and suppresses the volume expansion effect of the SiO material. • The discharge capacities of SiO@SiR and SiO@TiR reached 1105.62 mAh g−1 and 994.09 mAh g−1, respectively, after 100 cycles, demonstrating excellent cycling stability. Silicon monoxide (SiO) has gained popularity as an anode material for next-generation lithium-ion batteries due to its high theoretical specific capacity, moderate operating potential (0.4 V), low cost, and environmental friendliness. However, its large volume expansion (200 %) during charging and discharging, along with low electrical conductivity, limits its application. SiO@X composites with different cladding coatings were prepared. The results show that the composites with Si and Ti additions have discharge capacities of 1105.62 mAh g−1 and 994.09 mAh g−1 after 100 cycles, respectively, and their capacity retention rates are significantly greater than those of the other three composites. [ABSTRACT FROM AUTHOR]

• Micro-encapsuled composite spheres were fabricated by spray-drying. • The influence of composition on structure and property was studied. • Anisotropic conduction was demonstrated and mechanism was disclosed. A novel micro-encapsuled composite spheres was fabricated by multi-step process combining with chemical modification, physical deposition as well as spray-drying technique. The microstructure, morphology and compositions were comprehensively investigated. The optimized micro-encapsuled spheres were applied to construct epoxy resin-based anisotropic conductive film (ACF). The dielectric shell of the micro spheres was capable of disintegration under pressure, resulting into electric pathways. The transition from dielectric state to anisotropic conductive state was demonstrated for the microsphere-containing ACF epoxy resin. [ABSTRACT FROM AUTHOR]

• Bi 2 O 2 Te nanowires were grown via Au-catalyzed vapor–liquid-solid, solving challenge of fabricating 1D Bi 2 O 2 Te. • Growth of Bi 2 O 2 Te nanowires is influenced by crystal structure, Au nanoparticle distribution and liquid–solid interface dynamics. • This process transitions 2D Bi 2 O 2 Te to 1D and can unlock new properties. To address the growing demand for high-performance 1D nanostructured semiconductors, this study reports on the directional growth of Bi 2 O 2 Te nanowires facilitated by a Au nanoparticle-catalyzed vapor–liquid–solid (VLS) process. We reveal how the growth of Bi 2 O 2 Te nanowires is directionally influenced by the crystallographic orientation of the material and the dynamics at the liquid–solid interface, presenting the process's ability to transition the intrinsic properties of 2D materials into 1D nanostructures. [ABSTRACT FROM AUTHOR]

• The MS is multi-function and acted as a PCT. • The MS can realize two PC function in two frequency channels. • LP conversion can be seen in the 78.87 ∼ 81.90 THz. • CP conversion can be obtained in the 67.44 ∼ 72.11 THz. In this paper, a multilayer structure (MS) of Weyl semimetals (WSMs) is utilized as the foundation for a polarization converter (PCT) having two different functions in two frequency channels. An analysis of the transmission spectrum of this layer structure at varying incident angles and polarization directions is also included. We define the polarization deflection angle ϕ and discuss the structure's potential as a PCT with respect to the ϕ = 45° scenario. The incident angles were chosen as 0°, 5°, 10°, 15° and 20° for the analysis, and the results reveal that the incident linear polarization waves in the interval of 78.87 ∼ 81.90 THz can be effectively transformed into circular polarization ones for transmission case. While, for electromagnetic waves with frequencies ranging from 67.44 ∼ 72.11 THz, the direction of vibration for the electric field deflects by 45°. This work also provides positive insights into the design of polarization-related isolators, angle selectors, and other optical devices. [ABSTRACT FROM AUTHOR]

• A slip-mediated multilayer bending theory with two key parameters is proposed. • Gradient distribution and interlayer slippage evolution are quantitatively analyzed. • Concise and high accuracy solutions to deflection and bending stiffness are derived. • FEM and theory comparisons demonstrate significantly improved predictive accuracy. • Non-elastic interfacial slip model explains graphene's bending stiffness transition. This work introduces a novel approach to understanding the bending behavior of multilayer structures with weak interfaces. Despite the existence of various theoretical models, achieving high accuracy and computational efficiency remains a challenge. To address these limitations, we propose a Non-uniform Slip Model (NSM) governed by two essential dimensionless parameters: the number of layers and the shear factor. Utilizing the Semiparametric Hybrid Variational (SHV) method, we derive theoretical solutions that require less computational effort and offer enhanced accuracy. We further simplify the NSM through homogenization to the Uniform Slip Model (USM), yielding clear and concise analytical solutions for deflection curves and effective bending stiffness with high precision. The USM is also extended to account for nonlinear slipping interfaces with continuous shearing flow, providing an analytical stiffness expression that includes the bending angle. This extension explains the experimental observation of multilayered graphene's bending stiffness, which decreases from cubic to linear with increasing number of layers due to continuous slip and dislocation between atomic layers. Our study delivers theoretical insights for analyzing slip-mediated bending in laminated materials, paving the way for the design and optimization of such structures. [ABSTRACT FROM AUTHOR]

Abstract High‐performance multilayer dielectric elastomer actuators (DEAs) are well‐positioned to overcome the insufficient output force and energy density as artificial muscles. However, due to the fabrication process, the multilayer DEAs with nonmodifiable structures often suffer from the limitation of short lifespans and scalable preparation. Herein, reusable multilayer DEAs with the detachable and reconfigurable structure are fabricated. This is achieved by realizing scalable compliant electrodes using the continuous spatial confining forced network assembly (CSNA) method and combining the vacuum lamination (VL) approach to have good attachability and detachability with the VHB dielectric elastomer. The flexible roller‐based CSNA method is used to prepare the large area compliant electrodes composed of α, ω‐dihydroxy polydimethylsiloxane and electrically conductive nanoparticles. The fabricated electrodes can continuously work over 10 000 cycles at 40% strained stretching and maintain smooth surfaces to construct multilayer DEAs. Moreover, owing to the detachable configuration of the DEAs, the electrodes can also be recovered and reused for building new actuators. The lower limb assistive device is demonstrated by detachable multilayer spring roll DEAs, achieving approximately 3.1 degrees of flexion and extension movement of knee models under a voltage of 7 kV. The detachable and reconfigurable multilayer DEAs shed new light on the applications of wearable assistive devices.

We investigated the feasibility of designing and fabricating novel broadband radiofrequency (RF) absorbers for use in cavity-backed antennas. Fabricating the absorber involved a multi-material additive manufacturing (AM) approach that combined two polymer filaments: a low-loss dielectric filament and a lossy carbon-loaded filament. An iterative optimization algorithm was developed to deploy these filaments and create gradient distributions of material properties that minimize reflectance over a desired frequency band and a range of incident angles to achieve wideband electromagnetic absorption. The chosen material profiles were effectively realized using a spatially varying subwavelength lattice structure printed via fused filament fabrication. Experimentally, validation results demonstrated low reflectance over a wide frequency band, 10 to 40 GHz, and a range of incident angles, 0°–50°. Finally, this printed multi-material absorber was integrated within a cavity-backed spiral antenna and used to suppress backlobe radiation while maintaining an acceptable radiation pattern in the forward direction. While this study investigated cavity-backed antennas, these computational and experimental methods are potentially useful for a wide range of other applications.

A novel composite materials using silicon nitride (Si3N4) as the substrate and diamond particles as the reinforcement phase were developed to increase both thermal conductivity and mechanical properties. The Ti coating on the surfaces of the diamond particles facilitated the formation of a titanium carbonitride (TiCiN1-i) interface between the two constituents during sintering, creating a strong bonding for high thermal conduction at the diamond-Si3N4 interface and inhibiting the graphitization of diamond during the sintering process. Furthermore, a sandwiched material design was made whereby Si3N4 and Si3N4/Ti-coated diamond layers were stacked alternately to endow the composites with a directional heat conduction characteristic. The thermal conductivity of the fabricated Si3N4/diamond composites increased by up to 272.87 % compared to that of commercially available Si3N4, making them excellent candidates for thermal management materials required in high-performance electronic devices.

In this study, ternary layered double hydroxide (LDH) containing Zn, Cu, and Ni was synthesized successfully using hydrolysis route. Upon calcination at a lower temperature of 350 °C, the synthesized lattice transformed into ZnO containing Cu and Ni that can be reformed back to the layered structure simply by a phenomenon known as 'memory effect'. Furthermore, the synthesized lattice was used for the formation of polyaniline (PANI)‐based composite material. The structural and morphological details of the as‐prepared samples were studied using various spectroscopic techniques, that is, powder X‐ray diffraction (PXRD), Fourier transform infrared (FTIR), thermo gravimetric analysis (TGA), and scanning electron microscopy‐energy dispersive X‐ray analysis (SEM–EDX), indicating the formation of single‐phase ternary LDH as well as the successful incorporation of PANI in the interlayer region. Owing to the combined advantages of LDH and conducting polymer (PANI), zinc copper nickel layered double hydroxide (ZnCuNi‐LDH)/PANI composite may be exploited as a potential candidate for a variety of applications in the future. [ABSTRACT FROM AUTHOR]

This brief presents a new wide stopband substrate integrated waveguide (SIW) filter with multimode suppression based on a multilayer structure. All spurious modes below TE404 of a multilayer SIW filter operating in TE101 could be effectively suppressed by moving the intercoupling slots away from the sidewall by about 1/6 of the cavity’s width. To verify it, two prototypes are designed, fabricated, and measured. The results show a small size and a wide stopband of up to 4.03 ${f} _{0}$ (${f} _{0}$ is the filter’s center frequency) with a simple design. The proposed technology could be efficient for developing wide stopband SIW filters in wireless/microwave circuits and systems. [ABSTRACT FROM AUTHOR]

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

Current tribocorrosion research of metallic materials and their surface protective coatings mainly focuses on their short-term properties, with test time of 0.5–2.0 h and a sliding distance 50–500 m, which may significantly deviate from the practical long-term service condition and thus cause a catastrophe of marine equipments. In this study, three carbon-based multilayer coatings (Ti/DLC, TiCx/DLC, and Ti—TiCx/DLC) were deposited on S32750 substrates, and both short-term and long-term tribocorrosion behaviors were investigated. The experimental results indicate that the coatings substantially improve the tribocorrosion resistance of the S32750 stainless steel. During the short-term tribocorrosion test, TiCx/DLC exhibited the best tribocorrosion resistance owing to its high hardness. During the long-term tribocorrosion test, however, Ti—TiCx/DLC coating indicated the best anti-tribocorrosion performance owing to its excellent fracture toughness together with high hardness. Moreover, under 5 N, Ti—TiCx/DLC can withstand a long-term test of more than 24 h. Additionally, under a higher load of 20 N, the Ti—TiCx/DLC with a corresponding sliding distance of approximately 1,728 m maintained a low friction coefficient of approximately 0.06. However, the coating was completely worn out; this is attributable to the formation of tribocorrosion products consisting of graphitized carbon and nanocrystalline FexOy. [ABSTRACT FROM AUTHOR]

Integration of multiple superior features into a single flexible pressure sensor would result in devices with greater versatility and utility. To apply the device to a variety of scenarios and solve the problem of accumulation of e-waste in the environment, it is highly desirable to combine degradability and wide-range linearity characteristics in a single device. Herein, we reported a degradable multilayer fabric (DMF) consisting of an ellipsoidal carbon nanotube (ECNT) and polyvinylpyrrolidone/cellulose acetate electrospun fibers (PEF). The alternative layer-by-layer stacking of the ECNT and PEF notably accelerates the sensitivity toward pressure. The optimized device demonstrated a sensitivity of 3.38 kPa -1 over a wide measurement range from 0.1 to 500 kPa, as well as great mechanical stability over 2000 cycles. A good degradation performance was confirmed by both Fourier transform infrared (FTIR) characterization and decomposition experiments in sodium hydroxide solution. The fabricated sensor is capable of precepting a variety of physiological scenarios including subtle arterial pulse, dancing training, walking postures, and accidental falls. This work throws light onto the fundamental understanding of the mechanical interfacial coupling in piezoresistive materials and provides possibilities for the design and development of on-demand wearable electronics.

[Display omitted] • Fast drying spray deposition (FDSC) was developed as a scalable technique for fabricating perovskite solar cells with multilayer perovskite absorbers. • Graded energy band architecture was engineered, allowing extra built-in electric field and improved charge extraction. • FDSC was optimized for operation under high humidity condition without the need of post annealing process, enabling robust, low cost process with scalable potential. The fast-drying spray deposition (FDSD) technique for perovskite solar cells (PSCs) is developed to enable the stacking of perovskite absorbers with different work functions, which allows the creation of an additional built-in electric field at the interface during the fermi level realignment process upon contact. FDSD is functional under high relative humidity (RH) ambiance and by design, deposits dry film without the need for post-deposition annealing treatment. Based on a spray coating process, FDSD is also highly scalable. Leveraging FDSD's multilayer deposition capability, this work explores the implementation of graded energy band architectures to achieve PSCs with enhanced carrier extraction and photovoltaic performances. To demonstrate the potential benefit of this approach, two triple cation mixed halide perovskite formulas are chosen. The two formulas, when stacked together in correct order, produce a heterojunction PSC device with an extra built-in electric field, which helps drift charge carriers towards desired electrodes. The architecture with the proper energy band alignment therefore exhibits enhanced carrier extraction efficiency and, despite being subjected to over 60–80% RH during fabrication, reaches the mean power conversion efficiency (PCE) of 7.4%, with the maximum value of 9.5%. The average PCE translates to over 9.9% and 10.3% improvements over the devices based on the two constituent formulas individually. FDSD demonstrates great flexibility i.e., in-humid-air fabrication process and requiring no post annealing treatments, thereby enabling extremely robust and scalable stacked architecture PSCs with low cost and good performance. [ABSTRACT FROM AUTHOR]

The electromagnetic interference (EMI) shielding performance of reduced graphene oxide (rGO) foam is restricted to its poor conductivity and macro‐monotonic structure. In this work, highly conductive MXene nanosheets are introduced into graphene oxide (GO) solution and multilayer structures were designed to improve the EMI shielding performance of graphene foam. The multilayer rGO/MXene composite foam shows an excellent EMI shielding effectiveness of more than ≈28 dB in C and ≈35 dB in X band. Meanwhile, it reveals an outstanding heat insulation performance equaling to air (0.025 W m−1 K). The macro multilayer and microporous structure plays a prominent role in the EMI shielding and heat insulation performance. This work provides valuable ideas for designing multifunctional EMI shielding materials for the next generation of smart electronic devices. [ABSTRACT FROM AUTHOR]

Carbon/carbon (C/C) composites are widely used as thermal protection systems for atmospheric re-entry, where they are subjected to strong oxidation and mechanical denudation. Sublayer thickness of multilayer coating has considerable influence on its stress, which further governs their service life in critical environments. In this study, a multilayer coating with different sublayer thicknesses was fabricated on SiC-coated C/C composites using plasma spraying. Prior to the fabrication, finite element analysis (FEA) was firstly established to investigate the relationship between sublayer thickness and thermal stress. Thereafter, the coatings with typical sublayer thickness were verified through practical experiments. Raman spectra and ablated appearances showed well coincidence with the FEA results, pointing out close relationship among sublayer thickness, residual stress and ablation behavior. After testing for 90 s, the sample with optimized thickness owned the least stress (294 MPa) and lowest ablation rates (−0.467 µm/s and −0.343 mg/s) as compared to other coated ones. • A multilayer coating with different sublayer thicknesses was prepared on SiC-coated C/C composites using plasma spraying. • Finite element analysis model was established to explore the relationship between sublayer thickness and thermal stress. • Raman spectra and ablation profiles showed highly consistent with the simulated results. • The optimized sublayer thickness enabled the sample to sustain the least stress, further keeping an integrated profile. [ABSTRACT FROM AUTHOR]

Microelectrode array (MEA) is a powerful tool for recording electrophysiological signals and studying the electrophysiological features of nerve, retina, and cardiomyocytes. Stretchable electrodes can form conformal contact with dynamic biological tissues/organs (e.g. heart) to enhance the coupling efficiency in electrophysiological measurements. However, MEAs based on conventional materials require serpentine interconnections to enable stretchability. A large number of serpentine interconnects take up spaces and hinder the improvement of spatial resolution. Here, we introduce a multilayer design strategy that yields a stretchable MEA with spatial density of 7.3 sites mmâˆ'2 and biaxial stretchability of 30%. The serpentine interconnects of each layer overlap vertically to reduce the area of the wires used for connection. In vitro validation in phosphate buffered saline and ex vivo test on perfused mouse heart show a 100% yield rate of the multilayer stretchable MEA, with capabilities in spatiotemporal mapping of electrophysiological signals at high spatial resolution. [ABSTRACT FROM AUTHOR]

We create GeTe/Sb 2 Te 3 multilayer thin films by alternating GeTe and Sb 2 Te 3 to enhance thermoelectric properties. Crystal structure of the sample was characterized from amorphous to crystalline via annealing. The GeTe/Sb 2 Te 3 multilayer thin film can significantly improve thermopower factor from ∼0.1 μW/mK2 to 815.1 μW/mK2 because the interfacial effect breaks down the trade-off between Seebeck coefficient and conductivity. GeTe/Sb 2 Te 3 exhibits high Seebeck coefficient while maintaining large electrical conductivity under proper annealing at 575 K. Thus, a high power factor of 815.1 μW/mK2 obtained by the multilayer structure, which blocks carriers and rationally tunes the carrier density, leads to an enhanced Seebeck coefficient and power factor for thermoelectric devices. Improvement of electrical conduction originates from interfacial bonding and intermixing at a particular thickness ratio during element diffusion process. Results of microstructure characteristics revealed that the existence of hexagonal Ge 2 Sb 2 Te 5 phases may drive the improvement of thermoelectric performance and provide us with a new way of enhancing thermoelectric devices. [ABSTRACT FROM AUTHOR]

The goal of this project was to provide novel band-pass filter design techniques for mobile communications, which allow a significant reduction in the size of the filters produced. The novelty comes from the transformation of the single layer technique into a double layer technique by inserting coupling slots in a common mass plane. Because of their tiny size, these filters are suitable candidates for integration into mobile communication systems. Indeed, when compared to the dimensions of a single-layer planar filter, the multilayer construction allowed us to reduce the size of the filter by more than 40%. Five U-shaped hairpin resonators were placed on two micro-strip layers in the planned filter. Two apertures etched on a common ground plane positioned between the two layers allow varied couplings between the upper and bottom layer resonators. A five-pole hairpin band-pass filter was created as a result. [ABSTRACT FROM AUTHOR]

Based on the analytical solution, the paper focuses on the residual stress distribution in disklike composite specimens comprising ceramic layers of different composition during the cooling process after sintering to room temperature. It is shown that varying the layer thickness, it is possible to control the maximum stress distribution. With regard to diffusion zones at the interface between the neighboring layers with different thermal expansion coefficient, it is possible to reduce these dangerous stresses proportionally to the thickness of these zones. Note that for the engineering solution, it advisable to utilize the physical-and-mechanical parameters of composite components for high temperature, rather than for the average temperature. [ABSTRACT FROM AUTHOR]

Sustainable structural materials with fully bio-based building blocks and great mechanical properties are vitally important for practical application. However, the challenges on how to evitable use petrochemical-based adhesive, improve their comprehensive mechanical strength, and reduce energy and time consumption still remain. Here, we report a robust and effective strategy with micro/nanoscale structure design to fabricate a mechanically strong and sustainable wood-derived structural material from fast-growing wood. Owing to the synergistic effect of aligned cellulose fiber, multi-layer structure, and hydrogen bonds, the obtained structural materials exhibited high mechanical properties of 158 MPa, high interfacial bonding strength of 1.13 MPa, and great Shore D hardness of 68.7. The role of hydrogen bonds in enhancing mechanical properties was also revealed. In addition, the adhesive and polymer are not used in the whole process, and the consumption of energy and time is reduced. The novel fully wood-derived materials provide more structural material selection and more micro/nanoscale structure design ideas.

• Ultra-broadband photodetector of multi-junction structure of MoS 2 , Sb 2 Se 3 , and GaN. • The device demonstrates exceptional sensitivity across UV–C to IR–B wavelengths. • Photo-responsivity of 665 mAW−1 in photovoltaic mode and 3.89 × 105 mAW−1 in photoconductive mode. • TCAD simulations enhance understanding of the device's behaviour. Achieving an ultra-broad spectral response in a self-bias detector is a formidable challenge that persists in optoelectronics that necessitates innovative solutions. We propose a unique ultra-broadband photodetecting device, utilizing a multilayer structure comprising Molybdenum Di-sulfide (MoS 2), Antimony Tri-selenide (Sb 2 Se 3), and Gallium Nitride (GaN), which exhibits the unique capability of detecting photons without applied bias. The fabricated device demonstrates exceptional sensitivity to a wide range of illumination wavelengths, spanning from ultraviolet–C (UV–C) to infrared–B (IR–B). The design detector displays the highest photo-responsivity of 665 mAW−1 in photovoltaic mode and 3.89 × 105 mAW−1 in photoconductive mode. The designed detector also exhibits a minimal dark current of 90 nA and an extremely weak signal detection capability of ∼12 femto watt-hertz−1/2 at 6 V bias. Additionally, the thermal stability of the MoS 2 -Sb 2 Se 3 -GaN (Mo-Sb-Ga) multi-layer-based self-bias detector was explored. Under the self-bias conditions, the photodetector exhibits a stable behavior up to 250°C with a peak responsivity of 635 mAW−1. The thermal durability of the self-bias ultra-broadband photodetector indicates excellent potential for developing futuristic optoelectronic devices. Further, the performance of the developed detector was examined using Technology Computer-Aided Design (TCAD) simulations, providing valuable insights into the device behavior and the transport of photo-generated carriers, enhancing our understanding of the device operation and enabling performance optimization for diverse applications. [ABSTRACT FROM AUTHOR]

• RGO layer composite Cu/Ag metal mesh transparent heater (TH) was prepared. • The RGO/mesh composite structure showed a sheet resistance as low as 1.45 Ω/sq. • A temperature of 150 ℃ was achieved by applying a voltage of 1.8 V to the TH. • It exhibited excellent heating performance and temperature uniformity. A novel transparent heater (TH) composed of reduced graphene oxide (RGO)/metal mesh with enhanced heating performance and temperature uniformity, was prepared by thermal reduction in a tube furnace. The synergistic effect between the RGO layer and Cu/Ag mesh effectively improved the electrical properties of the RGO/mesh composite structure. Consequently, the TH demonstrated an efficient electrothermal performance (stable response temperature of 150 °C at 1.8 V) and more uniform surface temperature distribution. This work contributes to the development of composite TH devices for practical applications. [ABSTRACT FROM AUTHOR]

As the core unit of energy storage equipment, high voltage pulse capacitor plays an indispensable role in the field of electric power system and electromagnetic energy related equipment. The mostly utilized polymer materials are metallized polymer thin films, which are represented by biaxially oriented polypropylene (BOPP) films, possessing the advantages including low cost, high breakdown strength, excellent processing ability, and self-healing performance. However, the low dielectric constant (εr < 3) of traditional BOPP films makes it impossible to meet the demand for increased high energy density. Controlled/living radical polymerization (CRP) and related techniques have become a powerful approach to tailor the chemical and physical properties of materials and have given rise to great advances in tuning the properties of polymer dielectrics. Although organic-inorganic composite dielectrics have received much attention in previous studies, all-organic polymer dielectrics have been proven to be the most promising choice because of its light weight and easy large-scale continuous processing. In this short review, we begin with some basic theory of polymer dielectrics and some theoretical considerations for the rational design of dielectric polymers with high performance. In the guidance of these theoretical considerations, we review recent progress toward all-organic polymer dielectrics based on two major approaches, one is to control the polymer chain structure, containing microscopic main-chain and side-chain structures, by the method of CRP and the other is macroscopic structure design of all-organic polymer dielectric films. And various chemistry and compositions are discussed within each approach.