Search Results (758)

Metal–Insulator–Metal (MIM) tunneling diodes are among the most promising rectifying devices for long-wave infrared (LWIR) rectenna systems due to their ultrafast response and zero-bias operation. However, their performance is strongly dependent on the choice of electrode and dielectric materials, making the identification of optimal material combinations a key challenge. To address this issue, this theoretical study presents a numerical investigation of a new class of MIM diodes based on a quantum-mechanical tunneling framework. Novel combinations of transition-metal dichalcogenides (NbS₂, VSe₂, and TaS₂) as anode materials (M1), conductive carbides and nitrides (Mo₂C, VN, and V) as cathode materials (M2), and rare-earth oxide and oxyhalide compounds (Sc₂O₃, LaOF, and LaOBr) as tunnel barriers (I) were selected through an extensive literature survey. These materials were combined to design previously unexplored MIM architectures for LWIR rectification. The electrical transport and rectification properties were evaluated using the Simmons tunneling model by calculating the current density–voltage (J–V) and current–voltage (I–V) characteristics, together with key figures of merit (FOMs), including zero-bias resistance, asymmetry factor, nonlinearity, and responsivity, at room temperature (300 K). The effects of tunnel barrier height and dielectric properties on device performance were systematically investigated. Among all the investigated architectures, the TaS₂/LaOBr/V MIM diode exhibited the most promising overall performance, achieving an asymmetry factor exceeding 2.5 × 10⁵, a nonlinearity factor of 1, and a zero-bias responsivity of 10 V⁻¹ at 300 K. Furthermore, this structure demonstrated the highest current density and the most favorable I–V characteristics among the proposed material combinations. These results identify the TaS₂/LaOBr/V material system as a promising candidate for high-performance LWIR energy harvesting applications, owing to its optimized tunnel barrier height, which promotes efficient electron tunneling while maintaining excellent rectification properties. 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

Incorporating energy generated from regular human movement into wearable electronics offers a promising alternative to conventional batteries, enabling devices to power themselves by harvesting energy from motion and the surrounding environment. Ambient energy harvesting provides a pathway toward limitless, self-sustaining power and supports the development of cleaner, smarter wearable systems. Among various approaches, integrating hybrid mechanisms into footwear represents a transformative solution for sustainable power generation. In this work, a piezoelectric generator (PEG), an electromagnetic generator (EMG), and a triboelectric generator (TEG) were hybridized within a single architecture to harvest biomechanical energy from walking, jogging, and running. The device incorporates pressure-sensitive Lead Zirconate Titanate (PZT) sheets, a spiral spring with dual neodymium (NdFeB) magnets with wound copper coils, and a nickel foam with polytetrafluoroethylene (PTFE) for triboelectricity operating in contact–separation mode. A dedicated energy-management circuit comprising independent rectification, DC bus energy aggregation, supercapacitor storage, and voltage regulation was implemented to efficiently utilize the harvested energy. The system was optimized through simulation using SOLIDWORKS 2023 and validated experimentally by using LabVIEW-NI myRIO FPGA system and treadmill. The proposed hybrid device achieved an exceptional peak output power of 58 mW and a voltage of 7.4 V, enough to charge low-power wearable devices, significantly surpassing the performance of most reported standalone and hybrid insole energy harvesters. These results demonstrate the effectiveness of multimodal integration in broadening operational bandwidth, increasing energy density, and enhancing compatibility with wearable applications. Piezoelectric, Electromagnetic and Triboelectric Insole Energy Harvesting (PET-IEH) establishes a new benchmark in biomechanical energy harvesting and paves the way for next-generation self-powered and sustainable wearable electronics. Full article

Smart textile interfaces hold promise for battery-free wearable interaction, yet their adoption is limited by complex fabrication and insufficient on-body evaluation. We present TriboTex, a low-cost spray-patterning workflow that forms nylon–Cu–nylon triboelectric stacks on cotton textiles using laser-cut PET stencils and commercially available materials. The core consumables cost approximately USD 0.003/cm², and sensor geometry can be rapidly iterated by modifying only the digital stencil. Controlled characterization across nine devices from three fabrication batches showed a peak open-circuit voltage of 52.3 V and a maximum power density of 1870 µW/m² at 4 GΩ. The output retained 96.1% of its initial voltage after 1000 bending cycles and 94.2% after 24 h of simplified saline immersion. Three-sample environmental sweeps showed voltage amplitudes of 41.9–43.7 V from 15 to 45 °C, with a decrease to 27.7 V at 0 °C; the humidity response remained within 92.7–104.5% of the 20% RH value over 20–60% RH but decreased to 19.9% at 70% RH. Two wearable prototypes were developed: a single-electrode garment sleeve recognized tap, double-tap, and swipe gestures with 95.0% accuracy across 1200 trials from 12 participants; a single-electrode insole generated action-dependent peak voltages up to 123 V under repeated foot loading and was connected through a rectification and voltage-regulation module to charge a battery. Across the two 12-participant studies, attachment and fit stability emerged as shared integration requirements, while participant feedback and controlled humidity measurements highlighted moisture management as a priority for reliable on-body sensing and energy capture. The primary contribution is an accessible, low-cost, and geometry-flexible route for early-stage wearable sensing experiments and application demonstrations, supported by documented fabrication, electrical characterization, and human-centered evaluation. Full article

The sustainability of marine ecological conservation and restoration, a key issue in the implementation of Sustainable Development Goal 14 (SDG 14), which aims at reducing marine pollution, protecting and restoring marine environments, promoting the sustainable use of marine resources, and strengthening scientific monitoring requirements, depends not only on policy design and financial investment, but more critically on effective coordination among policy implementation, resource management, and performance feedback. This paper analyzes the institutional evolution of marine ecological conservation and restoration audit in China and the main issues and their causes based on the text analysis and qualitative interpretation of the 302 marine ecological issues in the audit reports publicly released by Chinese audit authorities from 2008 to 2024. Audits found that the problems were predominantly in three areas: policy accountability and strategic implementation; project approval and implementation management; and fiscal management and fund coordination. The emergence of these is strongly linked to the fragmentation of department responsibilities, mismatch between project management cycles and ecological restoration cycles, and inadequate coordination between fund allocation and ecological performance. Although some problems were repeatedly reported across different years, their observed temporal and spatial distribution was influenced by the scope of audit coverage and the extent of public disclosure. On this basis, this paper proposes to improve audit oversight in the three areas of policy accountability coordination, project life-cycle management, and the performance of fiscal funds. This is to promote the implementation of SDG 14 requirements along the chain of “objective–resources–projects–monitoring–rectification”, serve as a reference for improving the Chinese supervision and accountability mechanisms for marine ecological conservation and restoration, and provide practical experience from China on the implementation of SDG 14 at the levels of national policy implementation and public accountability. Full article

Grain warehouses are critical nodes in food storage, circulation, and reserve systems, and their safe operation is relevant to occupational protection, reserve stability, and food-system resilience. However, unsafe warehouse behaviors are still mainly identified through manual patrols and fragmented inspections, making continuous observation, cross-site coordination, and early intervention difficult. To address this problem, this study proposes a grain warehouse safety governance framework with federated visual intelligence. The framework combines a real-time visual perception module, data-local federated learning, and a city-level digital supervision platform. Drawing on the Wenzhou grain reserve application scenario, the study defines twelve visually observable risk categories, including personal protective equipment (PPE) violations, and links artificial intelligence (AI) recognition with multi-source inspection, spatial mapping, warning generation, collaborative verification, work approval, closed-loop rectification, and large-model-assisted analysis. A four-client technical pilot compares isolated local, centralized, Federated Averaging (FedAvg), and Federated Proximal Optimization (FedProx) training across three selected recognition tasks. The task-specific results provide quantitative evidence from held-out warehouse-level validation and an intermittent-client stress test. The best held-out weighted F1-score (F1) values were 0.7712 for crossing over a conveyor, 0.5891 for passing under a conveyor, and 0.8481 for missing five-point safety harness. In the one-small-client-absent stress test, FedProx achieved weighted F1 scores of 0.5701, 0.4324, and 0.8064 for the same tasks, respectively. The framework translates visual detections into warning outputs, management indicators, and accountable safety workflows under data-governance constraints. It positions computer vision (CV) as an automated observation mechanism for responsible AI governance and embeds visual intelligence into a human-confirmed, data-local, and auditable safety-management workflow for sustainable food-storage infrastructure. Full article

Vehicle-side weight is a key constraint in wireless power transfer (WPT) systems for electric vehicles, as it directly affects cost, installation, and vehicle integration. This paper presents a lightweight Vehicle Assembly (VA) based on a conventional Series–Series (SS) compensation topology and a phase-shift-controlled active rectifier, designed within the SAE J2954 framework. The architecture reduces vehicle-side passive components while enabling load adaptation through the rectifier conduction angle. A fixed-output-power time-domain methodology is used to compare two operating strategies. In the exact 2-ZVS mode, only two rectifier commutations satisfy the charge-based ZVS condition, whereas in the robust 4-ZVS mode all four commutations are constrained to achieve ZVS through joint optimization of the rectifier control parameters and switching frequency. In both cases, the primary DC voltage is adjusted to maintain a constant output power of 7.7 kW. Measured coupler parameters are used in the circuit model. Across the aligned position and two measured misalignment conditions, exact 2-ZVS achieves an estimated AC–AC resonant-link efficiency of 98.01–98.41% and a modeled DC–DC efficiency of 96.16–96.90%. Robust 4-ZVS remains feasible, but its higher circulating-current requirement reduces the corresponding efficiencies to 93.26–94.96%, respectively. Therefore, for the investigated system, exact 2-ZVS provides the best efficiency–soft-switching trade-off. The AC–AC metric includes only winding and capacitor-ESR losses. The DC–DC metric additionally includes the modeled conduction and output-capacitance transition losses of the primary inverter and active rectifier; gate-drive, control, and auxiliary losses are excluded. Full article

In this article, general operating principles for modern photocatalytic solar water-splitting systems are reviewed from a physics perspective, and their fundamental limitations are identified. Several potential approaches to overcome the identified limitations are proposed, and a new solar water-splitting system unifying those approaches based on plasmonic metal nanoparticles linked by a metal-insulator junction is described. Based on already existing scientific knowledge, some probable features of the proposed system are briefly discussed, and an initial theoretical analysis of electromagnetic wave-propagation modeling was performed with COMSOL Multiphysics software. In addition, some rectification capabilities for the metal insulator–metal junction embedded in the system are calculated using a simplified Simmons model for tunneling currents. A probable approach for initial system synthesis with existing nanotechnology techniques is proposed, and its limitations and probable bottlenecks are marked. Full article

Multi-modal image fusion integrates complementary information from different modalities to generate a unified representation that is informative for human perception and beneficial to downstream vision tasks. However, existing methods often inefficiently model global features and their cross-modal interaction is insufficient, resulting in the suboptimal preservation of structural details and modality-specific information. To address these issues, we propose SACMFuse, a structure-aware cross-modal interaction network for multi-modal image fusion. SACMFuse is built upon the linear complexity attention mechanism of LAMA, which enables efficient and effective global feature modeling. In this study, LAMA is extended into a CrossLAMA mechanism to facilitate deep-level information interaction among modalities. Within this framework, we propose a Frequency–Spatial Rectification Module (FSRM) that jointly models spatial-domain structures and frequency-domain representations in a unified manner. By perceiving and adaptively rectifying structural features across modalities, FSRM enhances the structural consistency and discriminability of the fused features. Furthermore, to strengthen cross-modal complementarity, we design a Difference-driven Cross-modal Interaction Module (DCIM), where inter-modal discrepancies explicitly guide information exchange among modalities. This mechanism encourages the network to focus on complementary structures while suppressing redundant responses. Extensive experiments on multiple datasets demonstrate that the performance of SACMFuse is competitive for the majority of metrics, providing a robust and advanced solution for image fusion tasks. Full article

The increasing accumulation of pharmaceutical residues in water environments poses serious threats concerning environmental safety and public health, mainly due to their tenacity, continuous bio-activity, and resistance to traditional wastewater treatment processing. Although many nano-bio/chemosensor systems have been reported for the monitoring and removal of pharmaceutical residues, the literature remains fragmented regarding their ability to integrate detection and remediation into a single platform. In this context, this review critically examines recent developments in nano-bio/chemosensor platforms for simultaneous detection and elimination of pharmaceutical effluents in wastewaters. Particular emphasis is placed on their functional integration, detection mechanisms, analytical performance, and removal pathways. This review covers the major pharmaceutical categories, including pharmaceutical drugs, antibiotics, hormones, perfluorinated compounds, and drugs of abuse and discusses nanostructured platforms based on metal organic frameworks (MOFs), nanochannel-based immunosensors, noble metal nanoparticles, layered double hydroxides, and hybrid composites. Detection approaches based on fluorescence modulation, electrochemical impedance, ionic current rectification, surface-enhanced Raman scattering (SERS), and colorimetric nanoenzyme activity could lead to extremely low detection limits. In addition, removal mechanisms such as adsorption, photocatalysis, advanced Fenton-induced oxidation processes, and nanoenzymes allow for high degradation efficiencies (>80–99%). Significant advantages for real-time monitoring and sustainable wastewater treatment can be achieved by multifunctional nanoplatforms that integrate detection and remediation capabilities. Finally, this review identifies current limitations and research gaps regarding practical application, matrix effects, regeneration, stability, scalability, and integration into real wastewater treatment systems and outlines future research directions towards more efficient and environmentally relevant multifunctional platforms. Full article

Safety hazards in coal mines are characterized by significant spatiotemporal heterogeneity, dynamic evolution, and multi-actor coupling. Traditional safety management models, which center on periodic inspections and accident rectification, struggle to achieve proactive risk identification and full-process control. To address this issue, this paper proposes a multi-scale, collaborative “four-in-one” safety management framework oriented toward the hazard lifecycle, based on the spatiotemporal evolution patterns of safety hazards. This framework integrates systems safety theory with the safety philosophy of socio-technical systems, viewing safety hazards as an evolutionary process shaped by the combined effects of spatial exposure, human behavior, organizational management, and dynamic states. It establishes a comprehensive safety governance system comprising precise risk identification, active personnel participation, closed-loop accountability governance, and intelligent dynamic feedback. By integrating the “Area–Point–Number” risk classification method; the “Two-way Risk Purchasing” incentive mechanism; the “Six-level, Six-step, and Three-chain” closed-loop management model; and the Hazard Alert System, the framework achieves the coordinated optimization of risk identification, hazard management, and information feedback. Application validation based on safety hazard data from a coal mine between 2017 and 2020 demonstrates that this method enhances the ability to identify potential risks and effectively reduces major hazard types, such as management deficiencies, unsafe behaviors, and unsafe conditions. The research findings indicate that this framework overcomes the limitations of traditional safety management—such as a single-entity approach, static inspections, and passive responses—and facilitates a shift in coal mine safety governance from hazard control to risk prevention and from manual, experience-based management to intelligent, collaborative decision-making, thereby providing a new theoretical approach for enhancing the safety resilience of complex coal mine production systems. Full article

GaP and ZnTe semiconductor crystals are numerically investigated for terahertz (THz) generation driven by ultrafast 10.6 µm CO₂ laser pumping. At this wavelength, low-order multiphoton absorption is effectively suppressed, enabling the study of intrinsic performance limits governed by nonlinear optical effects, material dispersion, and THz absorption. A one-plus-one-dimensional (1+1D) frequency domain propagation model is employed, including optical rectification, cascaded nonlinear interactions, self-phase modulation, second-harmonic generation, and pulse-front-tilt-related dispersion. The simulations reveal markedly different behavior in the two crystals. In ZnTe, the large effective nonlinear coefficient enables conversion efficiencies exceeding 1% while maintaining good THz pulse quality. In GaP, strong self-phase modulation and nonlinear pulse compression can enhance the predicted efficiency but at the cost of waveform distortion and increased damage risk. MV/cm-level THz electric fields are predicted in both materials; however, ZnTe provides a more favorable compromise between conversion efficiency and pulse quality. The results provide practical guidelines for optimizing CO₂-laser-driven semiconductor THz sources. Full article

Special orthogonal lateral-intake pumping stations on coastal plains face severe lateral deflection and recirculation in the approach channel and forebay. Their underlying evolutionary mechanisms remain unclear, and conventional rectification methods cause substantial hydraulic losses. Using numerical simulations and hydraulic model experiments, this study investigates these unfavorable flow patterns and proposes an original Combined Arc-Frame Flow Straightening Structure (CAFS). This newly proposed CAFS differs from existing structures, achieving effective flow pattern improvement with reduced hydraulic loss. Results reveal three typical flow regimes—S-shaped mainstream, branching flow, and recirculation—and the flow field is partitioned into four hydrodynamic zones: the Mainstream Incident Zone, Mainstream Impact Zone, Mainstream Reflection Zone, and Low-Velocity Recirculation Zone. Axial velocity uniformity and flow angle are strongly influenced by lateral velocity, while turbulent kinetic energy exhibits intrinsic correlations with vertical vorticity. Lateral velocity, recirculation intensity, and hydraulic losses all increase positively with the Froude number. The CAFS effectively suppresses the low-velocity recirculation zone. Quantitative data show an improvement of 46.40 percentage points in uniformity of axial velocity distribution, a reduction of 0.157 rad (9°) in velocity-weighted average angle, 60.98% less turbulent dissipation, and 38.85% less total hydraulic loss. This study clarifies lateral-intake defect mechanisms and provides a valuable engineering reference. Full article

Reliable cervical cytology classification remains difficult when rare diagnostic categories are represented by only a few labeled examples and exhibit substantial morphological overlap with neighboring classes. This study introduces HardNegRect, a lightweight inductive prototype-rectification module designed for low-support classification among fixed cervical cytology categories. The method constructs a class-specific hard-negative reference from the most similar competing prototypes and uses this inter-class context to predict a bounded, gated residual correction to each support-derived prototype. Because rectification depends exclusively on support information, the approach preserves independent query processing and avoids transductive access to the test distribution. HardNegRect was evaluated on two public cervical cytology benchmarks using common fold assignments, support sizes, held-out query sets, and draw-level metric aggregation for frozen-feature, metric-based, and optimization-based comparators. The study also includes a controlled component ablation study, a neighborhood-sensitivity analysis, and an additional-seed stability analysis. On Mendeley LBC, the clearest benefit occurred in the one-shot setting, where HardNegRect achieved a Macro-F1 of $0.9862\pm 0.0062$ and an SCC F1 of $0.9655\pm 0.0216$. On SIPaKMeD, the default $K_{\mathrm{hn}}=2$ configuration achieved Macro-F1 values of $0.9596\pm 0.0052$, $0.9626\pm 0.0048$, and $0.9616\pm 0.0048$ for $K=1,3,10$, respectively, numerically exceeding the strongest comparator mean at each support size. The controlled component ablation study associates the additional one-shot gain on Mendeley LBC with inter-class prototype correction rather than with embedding transformation alone. Overall, HardNegRect provides a lightweight, parameter-efficient, and geometry-aware extension to prototype-based low-support cytology classification, while patient-grouped, source-grouped, repeated-seed, and multi-center validation remain necessary before clinical generalization can be established. Full article

Gallium nitride (GaN) Schottky barrier diodes (SBDs) are promising for power electronics, but their reverse-bias leakage remains strongly influenced by the rectifying interface’s microscopic nature. We fabricated PtSe₂/n-GaN diodes with a transferred ultrathin PtSe₂ interlayer (∼1.56 nm, trilayer) to weaken direct interfacial chemical bonding. The Ti/PtSe₂/n-GaN devices exhibit a suppressed reverse leakage current density of $1.3\times {10}^{-7}{\mathrm{A}/\mathrm{cm}}^2$ at −1 V, a $7.5\times {10}^4$ rectification ratio at $\pm 1$ V, a 0.8 V turn-on voltage, and a 144 V breakdown voltage. Same-wafer Ti/n-GaN control devices display much higher leakage ($6.23\times {10}^{-5}{\mathrm{A}/\mathrm{cm}}^2$ at −1 V) and a lower rectification ratio ($1.144\times {10}^3$). Furthermore, Pt/PtSe₂/n-GaN devices reduce leakage to $1.19\times {10}^{-8}{\mathrm{A}/\mathrm{cm}}^2$ and increase the rectification ratio to $1.09\times {10}^5$. These results demonstrate the ultrathin interlayer effectively suppresses reverse leakage while preserving the rectifying interface’s sensitivity to anode metal selection. Full article