Search Results (3,366)

Boosting requirements for portable and wearable electronic systems have substantially stimulated sustainable advancement of high-performance flexible planar microsupercapacitors (MSCs). However, the low comprehensive electrochemical performance of flexible planar MSCs proves to be the major hurdle to practicality. Herein, the scalable manufacturing of integrated flexible planar MSCs based on graphene quantum dots (GQDs) with tandem-interdigitated architecture was demonstrated through modified liquid–air interfacial self-assembly and photolithography methods. These flexible planar MSCs exhibit exceptional overall electrochemical performance with an areal specific capacitance of 6.35 mF cm⁻², areal energy density of 3.53 μWh cm⁻², areal power density of 8.10 mW cm⁻², excellent cyclic stability maintaining 93.61% of their initial capacitance following 10,000 cycles of cyclic voltammetry operations, and outstanding mechanical flexibility, which attributes to the synergistic effects of GQD active materials, tandem-interdigitated microelectrodes and bendable flexible polyethylene terephthalate substrate. This work unveils a straightforward and scalable process for fabricating high power density, all-solid-state, and integrated flexible planar MSCs with rapid frequency response. Considering their practical utility, these devices hold significant promise as on-chip micro-power sources for portable electronics and wearable microsystems. Full article

In this study, Mo/β-Ga₂O₃ vertical Schottky barrier diodes (SBDs) were fabricated using a sputtering process, and the electrical characteristics were evaluated as a function of post-annealing temperature. β-Ga₂O₃ is an ultra-wide bandgap semiconductor (UWBG) with a bandgap of about 4.8 eV and a critical breakdown field of 8 MV/cm, a promising material for high-voltage power switching applications. Mo (molybdenum) has a higher work function (~4.95 eV) than the electron affinity (~4.0 eV) of β-Ga₂O₃, its melting point (2623 °C) is higher than Pt (1768 °C) and Ni (1455 °C), so it has excellent thermal stability, and it is selected as a Schottky metal. The device is a structure in which a Si-doped β-Ga₂O₃ epitaxial layer (10 μm, N_d-N_a = 2.2 × 10¹⁶ cm⁻³) is grown on an Sn-doped β-Ga₂O₃ substrate (415 μm, N_d-N_a = 4.5 × 10¹⁸ cm⁻³). The Ti/Au (10/40 nm) was used for the back ohmic junction and Mo (300 nm) was used for the front Schottky junction. Post-annealing treatment was performed at 400, 500, and 550 °C using a rapid thermal annealing process (RTA) in an Ar gas atmosphere, and in this process, the Schottky junction and ohmic junction were formed simultaneously. Electrical characteristics including current-voltage (I–V), capacitance-voltage (C–V), Schottky barrier height (SBH), ideality factor (n), turn-on voltage (V_on), on-resistance (R_on), on/off ratio, and breakdown voltage (BV) were evaluated. No obvious Schottky characteristics were observed before post-annealing treatment, which means that As-deposited Mo does not form a rectifying junction on the β-Ga₂O₃ without post-annealing treatment. After post-annealing treatment, the I–V curve of the Schottky rectification characteristics could be confirmed under all three conditions. Among the three conditions, the device annealed at 500 °C exhibits best performance, with an SBH of 0.96 eV, n of 1.01, V_on of 0.72 V, R_on of 13.8 mΩ·cm², an on/off ratio of 10⁹, a breakdown voltage of −474 V, and a PFOM of 16.3 MW/cm². As a result of temperature-dependent I–V measurement, as chuck temperature increased, the reverse leakage current increased and SBH decreased in all devices, which is consistent with the thermally activated carrier transport. These results demonstrate that the Mo/β-Ga₂O₃ SBDs are a thermally stable contact for power device applications. Full article

Introductory and intermediate electrical-engineering education commonly models fundamental circuit and device parameters, including inductance, capacitance, resistance, permeability, permittivity, conductivity, characteristic impedance, transformer turns ratio, machine constants, amplifier gain, resonant frequency, propagation velocity, and mutual inductance, as numerical constants. While this approximation is valid within the intended small-signal operating regime, it becomes methodologically incomplete when these coefficients exhibit measurable state dependence. This paper presents a comparative audit of thirteen such coefficients by systematically contrasting their textbook formulations with the established engineering literature and interpreting the results through two complementary frameworks: the JCGM GUM-6:2020 measurement-model methodology for omitted effects, and the Heckmann–Nye/Gasik multidomain coupling architecture for multi-axis physical interactions. The analysis demonstrates that mainstream engineering practice routinely exploits state-dependent coefficients without invoking new physical laws, and that relaxing the constant-coefficient assumption naturally introduces physically meaningful terms, including the inductive contribution $I\mathrm{d}L/\mathrm{d}t$, the capacitive counterpart $V\mathrm{d}C/\mathrm{d}t$, and the mutual-inductance term $i_2\mathrm{d}M/\mathrm{d}t$. The principal scientific contribution is the development and experimental validation of a unified theoretical and engineering framework for high-power resonant transformers and orthogonal Metglas AMCC-1000 paraformers. The proposed approach combines a new physics-based modal theory of octave ($2:1$) parametric excitation with simultaneous optimization of magnetic-core resonance, electrical resonance, nonlinear inductance modulation, resonant conductor lengths selected as integer multiples of the operating resonant wavelength, multi-stranded high-frequency Litz-wire windings, resonant capacitor synthesis, and the nonlinear magnetic characteristics of the AMCC-1000 amorphous core. The modal analysis demonstrates how coupled resonant eigenmodes and engineered state-dependent inductance can be used to satisfy the conditions for stable octave parametric excitation. Experimental results obtained from both the symmetric two-leg resonant transformer and the orthogonal paraformer are in close agreement with analytical predictions and numerical simulations, thereby validating both the proposed electromagnetic design methodology and the underlying modal theory. Full article

Experimental measurements and two-dimensional axisymmetric fluid simulations are performed to study coaxial argon dielectric barrier discharge. Oscilloscope measurements capture voltage–charge waveforms and Lissajous figures to resolve cycle-integrated electrical characteristics. Continuous-integration optical emission spectroscopy without phase resolution is used to qualitatively verify metastable argon. As peak voltage rises from 5 kV to 13 kV, the simulated volume-averaged electron temperature displays a pronounced N-shaped trend: it peaks at 9 kV, falls abnormally between 10 kV and 11 kV, and recovers at higher voltages. This non-monotonic variation arises from intra-cycle self-shielding by dielectric surface charges together with power-broadening driven by discharge spatial expansion. Monotonically increasing equivalent capacitance confirms continuous surface charge accumulation, and the simulated inward shift of the high-electron-temperature region validates the emergence of surface-charge-induced reverse electric fields. The discharge maintains a steady filamentary regime across all tested conditions. Because microdischarge filaments occupy only a small portion of the gap, the volume-averaged electron density from simulations is far lower than the peak density within individual streamers. This work elucidates the mechanism underlying the anomalous electron temperature drop at moderate voltages and offers guidance for controlling atmospheric-pressure filamentary DBD. Full article

Reliable tactile object shape recognition on robotic hands is often achieved using dense sensor arrays or vision-based tactile skins, which increase fabrication complexity and computational cost. This work demonstrates that high-recognition performance can instead be achieved through principled sparse sensing. A minimal multimodal tactile system is developed by fusing soft capacitive stretch sensors at the proximal interphalangeal and metacarpophalangeal joints of the fingers with a sparse six-element palmar pressure array, integrated into a human-like hand mechanically constrained to emulate robotic grasping under a controlled and repeatable protocol. Using an ANOVA-based channel selection, low-informative metacarpophalangeal signals are identified and removed, reducing the number of sensors at the finger joints while improving classification accuracy. A lightweight multi-layer perceptron operating on this low-dimensional input achieves 95.4% size-invariant recognition accuracy across 12 rigid objects representing four geometric primitives—cuboid, sphere, cylinder, and cone—outperforming the denser baseline. Ablation studies confirm the complementary roles of finger-joint deformation, which encodes curvature cues, and palmar force distribution, which captures contact topology; neither modality alone achieves comparable performance. Beyond accuracy, the proposed design reduces sensor count, wiring, and computational requirements, enabling embedded-ready deployment. The results show that data-driven sensor placement, rather than sensors at all finger joints, can yield sufficient grasp-based shape recognition, offering practical guidance for tactile perception in resource-constrained robotic hands. Full article

The growing demand for sustainable, flexible, and high-performance electrode materials for energy storage has motivated the development of polymer-based composite electrodes with enhanced electrochemical properties. In this study, flexible cobalt oxide (Co₃O₄)-iron oxide (Fe₂O₃) nanoparticle-impregnated sodium alginate (NaAlg) as the polymer matrix composite membranes were developed via a simple solution-casting method to exploit the synergistic pseudocapacitive behaviour of mixed metal oxides together with the excellent film-forming ability, flexibility, and eco-friendly nature of NaAlg. The prepared membranes’ structural features, morphology, and electrochemical properties were examined through a set of techniques, such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Universal Testing Machine (UTM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), potentiodynamic polarisation (PDP), and galvanostatic charge–discharge (GCD). Characterisation techniques validated the effective loading of Co₃O₄ and Fe₂O₃ nanoparticles within the NaAlg matrix, and revealed the efficient interfacial interactions, structural integrity, and electrochemical properties of the composites. GCD tests showed a very high specific capacitance of 571.43 F g⁻¹ at 1.2 A g⁻¹. The best-performing electrode produced a top energy density of 155.56 Wh kg⁻¹ at a power density of 2800 W kg⁻¹ and still showed around 91% capacitance retention after 2500 charging–discharging cycles with coulombic efficiency close to 100%. Boosted electrochemical performance is due to the synergistic effect of Co₃O₄-Fe₂O₃ nanoparticles that not only offer plenty of electroactive sites but also help in effective electron and ion transport within the polymer matrix. The results obtained here confirmed the capabilities of Co₃O₄-Fe₂O₃@NaAlg composite membranes as green and potent electrode materials for future supercapacitor devices. Full article

This paper investigates the Electrode Induction Gas Atomization (EIGA) of a Class 4 tungsten heavy alloy (WHA-4) containing 97.8 wt.% W, with the balance comprising Ni and Fe. Compared with conventional tungsten heavy alloys containing less than 95 wt.% W, the high tungsten content reduces the liquid-phase fraction and melt fluidity, making stable processing significantly more challenging. Powder-metallurgy-fabricated electrodes were atomized under varying resonant induction conditions to evaluate the effects of capacitance, frequency, and input power on melt stability. The results show that stable processing can be achieved through an optimum combination of capacitance and resonant frequency, providing sufficient energy to maintain a steady melt stream and uninterrupted atomization. Under optimized conditions, predominantly spherical powders with minimal defects were successfully produced. Microstructural characterization revealed that the Ni–Fe binder phase remained localized along tungsten grain boundaries and in isolated pockets between tungsten grains. X-ray diffraction and chemical analyses confirmed that the phase constitution and alloy composition of the electrode were preserved during atomization. Under non-optimum conditions, process instability was associated with incomplete melting, beard formation, unstable melt flow, and nozzle blockage. These findings provide new insights into the atomization behavior of high-tungsten heavy alloys and establish practical processing procedures for producing high-quality WHA-4 powders for advanced manufacturing applications. Full article

Fast and accurate detection of missed and multiple seeding, followed by timely correction, is needed to maintain potato planting quality. Photoelectric, laser, capacitive, and machine vision methods have been developed for defect detection. Backup metering channels, catch-up compensation, in situ release, preparatory seed belts, and electric reseeding devices have also been used for correction. However, stable field use remains limited. Reported outcomes often cover detection accuracy, model performance, or single-action success, but end-to-end verification from defect detection through reseeding to outcome checking is not consistently available. Using a structured search of international and Chinese databases and citation screening, this review synthesized 88 publications published by 1 June 2026. The review compares the principles, reported performance, and operating conditions of the main detection methods and considers planting-quality control and reseeding in a broader agronomic context. Photoelectric and capacitive sensors generally produce clear event signals with simple processing. Machine vision provides more detailed class and position information but is more sensitive to lighting, occlusion, vibration, and computing delay. The analysis shows that high detection accuracy alone does not ensure reliable field correction. Performance also depends on sensor position, space-time matching, reseeding method, actuator response, and post-action checking. Future studies should use a wider set of metrics, conduct longer field tests under varied conditions, and improve the coordination of detection, control, actuation, and verification. These comparisons can inform sensor selection, correction-system design, and field evaluation protocols for potato seed-metering detection and reseeding systems. Full article

To overcome the problems of poor durability and structural incompatibility inherent in conventional urban traffic monitoring technologies, this study develops a self-sensing asphalt concrete composite incorporating carbon fiber (CF) as a conductive functional filler to construct an internal conductive network. The effects of CF dosage and loading rate on the electrical and dynamic piezoresistive characteristics of the composite were systematically investigated. Furthermore, the evolution mechanism of the micro-conductive network was revealed via electrochemical impedance spectroscopy (EIS) coupled with equivalent circuit modeling. The results demonstrate that the electrical resistivity follows a two-stage percolation behavior (“sharp decline followed by stabilization”) with increasing CF content, yielding a percolation threshold of 0.2 wt%. As CF dosage increases, the Nyquist plots transition from quasi-linear profiles to a fully developed single semicircle, and eventually to an alternating pattern of high-frequency capacitive arcs and low-frequency diffusion impedance. Equivalent circuit analysis reveals that higher CF loadings reduce both contact and tunneling resistances while simultaneously elevating interfacial capacitance. Under monotonic loading, the developed conductive network enables enhanced piezoresistive responses, and the 0.2 wt% group achieves the most pronounced improvement relative to the 0.1 wt% group, with the maximum resistivity change rate and stress sensitivity increasing by 82.05% and 313.59%, respectively. Moreover, the specimens exhibit the optimum piezoresistive response under a dynamic loading rate of 250 N/s. This study clarifies the variable-frequency sensing mechanism of self-sensing asphalt concrete, providing scientific guidance for dynamic speed measurement and weigh-in-motion (WIM) monitoring in smart pavements. Full article

Selenomethionine (SeMet) is essential for selenium fortification in the hyper-selenophilous plant, Cardamine violifolia (Cv). However, there is currently a lack of real-time monitoring techniques to investigate SeMetfortification in Cv. In this study, we employed a time-course experiment (0–10 days) under different concentrations of SeMet (0–300 mg/L). Based on the growth characteristics of Cv, SeMet supplementation was most effective on day 4 at 100 mg/L. Compared with CK, the fresh weight of the roots, stems, and leaves, as well as the total chlorophyll and total nitrogen content, increased by only 2.7–32.9%. Furthermore, based on electrophysiological water metabolism and nutrient translocation in Cv leaves, an electrophysiological indicator, ESR, was used to evaluate selenium biofortification with SeMet. We found that electrophysiological responses are more sensitive than growth traits; the intrinsic capacitance (ICp) of S2 is 173% higher than that of CK, whilst IR, IZ, IX_C and IX_L are reduced from 44.4% to 73.68%. Intracellular water-holding capacity (IWHC), water transfer rate (WTR), nutrient translocation rate (NTR), and electrophysiological metabolic activity (MA) increased by 144–264%, enhancing SeMet enrichment efficiency. However, when SeMet > 100 mg/L (S3–S6), intracellular water metabolism and active nutrient transport were reduced, leading to the IWHC of S6 being 32.8% lower than CK. Moreover, although the ESR of S6 is higher than CK, the total SeMet transport capacity (STC) of Cv is reduced, promoting the efflux of SeMet (ES2) to inhibit high SeMet stress. Correlation analysis indicated that the electrophysiological selenium-enhancing rate (ESR) is significantly positively correlated with Cv biomass (R² = 0.89, p ≤ 0.05) and leaf area (R² = 0.85, p ≤ 0.05), showing that it served as an electrophysiological factor of selenium biofortification. Hence, plant electrophysiological technology enables real-time monitoring of different SeMet biofortification in Cv, and ESR can provide a useful reference for assessing selenium biofortification in hyperaccumulators. Full article

Aligned with green chemistry principles and the pursuit of sustainable synthesis, we developed a lignin–resorcinol–furfural (LRF) gel system within a deep eutectic solvent (DES), in which lignin partially replaces resorcinol and furfural serves as a bio-based alternative to formaldehyde. We further examined the correlation between the lignin substitution ratio (65–90%) and the gelation kinetics, microstructure, and electrochemical performance of the resulting carbon aerogels (LRFC). The findings reveal that the lignin substitution ratio exerts a critical influence on both the crosslinking uniformity and the overall network architecture of the resulting LRFC. The results demonstrated that LRFC65, with a lignin substitution ratio of 65%, exhibited the optimal electrochemical performance: a specific capacitance of 117.2 F g⁻¹ at a current density of 0.2 A g⁻¹, along with lower charge transfer and diffusion resistance. This work offers promising prospects for high-value bio-based furfural and lignin valorization. Full article

Supercapacitors require electrode materials with highly developed microporosity, which can be easily achieved via chemical activation. Physical activation is a more practical and environmentally benign route because of its technical feasibility and the absence of corrosive reagents; however, it often results in less developed pore networks. Herein, we report a tailored CO₂ activation strategy able to convert food waste into activated carbons with very high specific surface areas (2048–3195 m² g⁻¹) and suitable pore size distributions that make them strong candidates for supercapacitor electrodes. The electrochemical performance was investigated in the ionic liquid electrolyte EMImBF₄, where the materials exhibited a high capacitance of up to 172 F g⁻¹, good rate capability, and a stable cycling performance. The results demonstrate the technical feasibility of producing high-performance porous carbons using CO₂ activation of biomass residues. Full article

Although traditional carbon-based supercapacitor electrode materials exhibit good cycling stability and conductivity, their specific capacitance and energy density are limited by the dual-layer capacitor storage mechanism, making it difficult to satisfy the growing demand for high-performance energy storage. Consequently, the introduction of pseudocapacitive materials with Faradaic charge transfer characteristics has become a research focus in the field of supercapacitors. Herein, Cu/Co metal-anchored carbon composites (IL-Cu@NC and IL-Co@NC) have been successfully synthesized using metal-functionalized ionic liquids as both precursors and dopants via a one-step carbonization process. The micro-morphology, crystallinity, surface chemical states, and pore structure of the prepared electrode materials have been systematically characterized using scanning electron microscopy (SEM), chronoamperometry, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and N₂ adsorption–desorption measurements. The energy storage performance of the fabricated electrode materials has been investigated using a three-electrode system in an alkaline solution. The optimized IL-Cu@NC electrode achieves a specific capacitance of 653 F g⁻¹ at 0.5 A g⁻¹, along with stable cycling performance. This research proposed a feasible strategy for developing high-performance supercapacitor electrodes by functionalizing metals with ionic liquids, achieving enhanced specific capacitance compared with conventional carbon materials. Full article

To address the issue of noise affecting the accuracy of the SAR ADC sample-and-hold circuit in battery management chips, a low-noise sample-and-hold circuit employing a charge-sharing technique is proposed to suppress the noise from both switches and the operational amplifier. By utilizing capacitance multiplication technology, a large effective capacitance is realized with a small physical capacitor, enabling more thorough noise suppression while avoiding the layout area penalty associated with large capacitors. Through the regulation of switching timing, the system operates in a discrete-time mode, thereby preventing loop instability that may arise from a closed-loop configuration, while still fulfilling the sample-and-hold function. The capacitance multiplication circuit employs a low-noise operational amplifier, which relaxes the design requirements for the amplifier in the main ADC signal path. The proposed circuit is designed using a standard commercial 0.35 μm BCD process and verified through Cadence Virtuoso (Version: IC617) with the Spectre simulator (Version: 15.1), including transient-noise and process-temperature corner analyses. The results demonstrate that, at a sampling frequency of 20 kHz, the proposed low-noise sample-and-hold circuit for SAR ADC achieves an effective number of bits (ENOB) of 14.03 bits, a signal-to-noise-and-distortion ratio (SNDR) of 86.02 dB, and a spurious-free dynamic range (SFDR) of 91.89 dB, providing theoretical guidance for high-precision multi-cell battery management chips. Full article

This study examines the corrosion behavior of nitinol (NiTi) across its transformation range (10–60 °C) using a multimodal approach combining electrochemical testing with advanced surface and compositional characterization. The results reveal a distinct phase-dependent corrosion response. At 10 °C, fully martensitic NiTi exhibited the lowest corrosion current density and the most stable passive film, confirmed by electrochemical impedance analysis showing high film ideality and low pseudo-capacitance. At 20 °C, a mixed martensite–austenite structure led to degraded corrosion performance, reflected by increased current density and reduced passive film stability. Despite this, at 10 °C, the fully martensitic surface exhibited no measurable pit damage (0% surface coverage), while the mixed structure at 20 °C maintained minimal damage at 0.14% surface coverage. Corrosion susceptibility increased at 40 °C due to the higher phase mismatch combined with enhanced chloride activity, resulting in reduced electrochemical performance and substantial pit damage, increasing the surface coverage to 15%. At 60 °C, the fully austenitic structure partially restored corrosion resistance and reduced pitting severity. These results establish a direct link between NiTi’s thermo-mechanical phase state and its corrosion behavior, highlighting the critical role of phase coexistence and microstructural heterogeneity. The findings provide guidance for designing corrosion-resistant NiTi components for harsh environments such as marine and energy applications. Full article