Search Results (255)

High-density 380 V–12 V $LLC$ resonant converters typically employ planar transformers with integrated leakage inductance. To achieve Zero-Voltage Switching (ZVS), an air gap is introduced to adjust the magnetizing inductance ($L_m$). However, this gap alters the internal magnetic field (H) distribution. In Center-Tapped (CT) structures, this alteration leads to asymmetric leakage inductances between the positive and negative half-cycles, causing resonant frequency mismatch and performance degradation, particularly under light-load conditions. In this work, the asymmetrical leakage inductance effect in a CT transformer for a 380 V–12 V $LLC$ resonant converter is systematically investigated. A mathematical model is derived to quantify the leakage inductance distribution, revealing that the relative position between the air gap and the windings significantly affects the symmetry. Based on this modeling analysis, the centralized assembly method is identified as the optimal solution to ensure impedance symmetry. The accuracy of the proposed model and the effectiveness of this structure are validated through Finite Element Analysis (FEA) simulations and a hardware prototype of a 250-W, 600-kHz $LLC$ converter. Results demonstrate that this method eliminates the approximately 11% leakage inductance discrepancy (1.8 μH vs. 1.6 μH), ensuring stable operation across the full load range. Full article

To enhance the accuracy and timeliness of field testing for grounding impulse impedance in complex soil environments, this paper addresses the limitations of traditional peak-ratio methods—such as susceptibility to noise interference and the inability to reflect dynamic impedance variations—by proposing an identification method that combines an improved Hanning window with recursive least squares (RLS). During signal preprocessing, an improved Hanning window with adjustable parameters and energy normalization is employed to enhance the main-lobe energy concentration of impulse voltage and current signals while effectively suppressing high-frequency sidelobe leakage. In the parameter estimation stage, a low-order discrete linear model is established and an RLS algorithm with a forgetting factor is introduced to achieve full-time adaptive estimation of impulse impedance. Using a simulated surge test circuit, 18 sets of typical operating conditions with varying inductance and resistance parameters are designed. The same voltage and current data are processed using three processing methods: no windowing, standard Hanning windowing, and improved Hanning windowing. Results show that the average relative error of surge impedance is 9.16% without windowing, the standard Hanning window reduced the error to 3.78%, and the modified Hanning window further decreased the error to approximately 1.51%. Comparative analysis of different forgetting factor settings indicates that a value of approximately λ = 0.98 achieves an optimal trade-off between dynamic tracking capability and steady-state smoothness. The research results demonstrate that the proposed method achieves high identification accuracy for impact impedance and exhibits satisfactory parameter robustness under strong noise and multiple operating conditions, providing a reference for grounding impact characteristic testing and lightning protection design. Full article

In this paper, the influences of leakage inductances are investigated for the integrated transformer of an input-series flyback converter, in which each input-series circuit is based on the single-switch flyback topology. First, the configuration of this converter is introduced, and a novel multiple-inductor coupling model is proposed for its flyback integrated transformer. Second, the operational process of this converter is analyzed by considering the leakage inductances between the primary and secondary windings of its integrated transformer. Third, the influences of these leakage inductances are analyzed; on this basis, the essential design considerations of the flyback integrated transformer are summarized. Finally, an experimental prototype of this input-series converter is built. Based on this, the analysis is verified by the experimental comparisons among three flyback integrated transformers with various winding layouts. Full article

Ciboria shiraiana (C. shiraiana), a pathogenic fungus, is a major threat to mulberry trees, causing mulberry sclerotinia diseases. Current control strategies primarily rely on chemical pesticides, whose long-term use leads to adverse effects such as pesticide residues, environmental pollution, and pathogen resistance. This study aimed to develop a green pesticide derived from the essential oil (EOs) of Solidago canadensis L. (S. canadensis L.) and to analyze its antifungal mechanism. SLEOs were extracted from flowers, leaves, and stems of S. canadensis L. via hydro-distillation. Their chemical composition was analyzed by GC-MS. Multivariate statistical analysis was used to assess compositional differences among SLEOs from various plant parts and evaluate the correlation between their chemical components and antifungal efficacy. The antifungal mechanism of SLEOs against C. shiraiana was investigated using an integrated approach combining transcriptomics with physiological and biochemical analyses. The EO yield varied with plant part: flowers yielded the most (1.00% ± 0.07%), followed by leaves (0.76% ± 0.04%) and stems (0.05% ± 0.01%). Flower EOs (FEOs) strongly inhibited C. shiraiana, with an EC₅₀ value of 0.642 μL/mL. α-pinene and myrcene showed the highest correlation with antifungal activity. Transcriptomic and physiological data revealed that SLEOs compromise cell wall and membrane integrity, infiltrate cells, and trigger leakage of intracellular contents. Additionally, SLEOs inhibited activities of antioxidant enzymes (SOD, CAT, and POD), leading to intracellular ROS accumulation, oxidative stress, lipid peroxidation, and DNA damage. SLEOs constitute a promising natural and environmentally sustainable antifungal agent. Their activity is linked to specific components and a multi-target mechanism involving membrane disruption and oxidative stress induction. This study provides a foundation for developing plant-based agents to manage mulberry sclerotinia diseases. Full article

Transformer modeling is a crucial method for analyzing transient phenomena such as inrush currents. The primary characteristic of a transformer transient model is its ability to reflect how the transformer’s structure and material properties influence the magnetic and electric fields. In high-voltage direct current (HVDC), the single-phase converter adopts a double-core-limb and double-side-limb configuration, whose core structure, magnetic flux distribution, and ferromagnetic materials differ from conventional power transformers. This paper conducts research on low-frequency transient modeling of single-phase four-limb converter transformers. This study first determines the magnetic field distribution of the single-phase converter transformer with the inclusion of leakage flux. Subsequently, a corresponding model is derived from the principle of duality. Due to the laminated structure, the iron core exhibits different excitation characteristics from those of a single silicon steel sheet. For the excitation branch, AC-DC hybrid excitation is used to measure incremental excitation inductance and the nonlinear excitation curve is calculated based on this inductance. Furthermore, the allocation method of this curve in the core limb, side limb, and yoke is proposed to establish the converter transformer model. The results of no-load and inrush current tests based on the scaled model validate the effectiveness of this model, which can accurately calculate the inrush current under different remanence and closing conditions. Full article

Postharvest chilling injury (PCI) is a significant limitation in the storage of temperature-sensitive fruits, leading to quality deterioration and reduced marketability. However, low temperatures delay senescence—consistent with the Q10 principle, where metabolic reaction rates change 2–3-fold per 10 °C—and chilling-sensitive fruits experience membrane destabilization, oxidative imbalances, and structural degradation under cold stress. Physiological assessments consistently report elevated electrolyte leakage, increased malondialdehyde accumulation, and reduced membrane fluidity, coupled with disruptions in respiration and cellular energy metabolism. Biochemically, PCI is characterized by enhanced ROS production and a 20–50% decline in key antioxidant enzymes, along with disturbances in calcium signaling and hormone regulation. At the molecular level, chilling-responsive transcription factors such as CBF, CAM, HSF, and WRKY show strong induction, while lipid remodeling and epigenetic modifications further shape cold adaptation responses. Advances in multi-omics, including transcriptomics, proteomics, metabolomics, lipidomics, and volatilomics, have revealed chilling-associated metabolic shifts and regulatory cascades, enabling the identification of potential biomarkers of tolerance. Emerging mitigation strategies, including physical and chemical treatments, as well as CRISPR-based interventions, have shown a 30–60% reduction in PCI in controlled studies. This review synthesizes recent progress in physiology, molecular biochemistry, and postharvest technology to support future research and practical PCI management. Full article

The leakage inductance of high-frequency transformers (HFTs) is a critical parameter affecting the performance of power electronic equipment, such as DC-DC converters. During the transformer design phase, by precisely calculating and retaining an appropriate amount of leakage inductance, the independent inductors in the original topology can be replaced, thereby reducing the size of the converter. This paper derives the analytical expression for the magnetic field distribution in the core window, based on Dowell’s one-dimensional model system. A leakage inductance calculation model is established using the square integral of the magnetic field strength. The study investigates the effects of winding spatial distribution and operating frequency on leakage inductance. Finally, the model’s accuracy is verified through experimental measurements, with the results aligning closely with those obtained from the analytical method, and the error falling within a reasonable range. Full article

Subarachnoid hemorrhage (SAH) is a devastating cerebrovascular disorder with high mortality and long-term disability. It is more prevalent in women than men, but most preclinical research has been performed in male animals. Upregulation of lipocalin-2 (Lcn2), an acute-phase protein involved in iron homeostasis and neuroinflammation, has been implicated in hemorrhagic brain injury in male animals. The purpose of this study was to examine whether genetic deletion of Lcn2 also reduces early brain injury after SAH in female mice. Adult female wild-type (WT) and Lcn2 knockout (KO) mice were subjected to endovascular perforation to induce SAH. Lcn2 expression was assessed by immunohistochemistry and Western blotting, while brain injury was evaluated using MRI T2 lesion measurement, blood–brain barrier (BBB) permeability assays, Fluoro-Jade C staining, and Garcia’s neurological scoring. We found that Lcn2 expression was upregulated in multiple brain regions after SAH, particularly in astrocytes. Compared with WT mice, Lcn2 KO mice exhibited significantly reduced oxidative stress, attenuated ferritin induction, smaller T2 lesions, decreased BBB leakage, reduced neuronal degeneration, and improved neurological recovery over 7 days. These findings identify Lcn2 as a critical mediator of early brain injury after SAH in female mice. These results further support targeting Lcn2 as a therapeutic strategy to reduce brain damage and improve outcomes in SAH patients. Full article

Ensuring the safe operation of large hydro-generators is essential for energy supply and economic development. Stator-winding single-phase grounding faults are among the most common failures in such generators. Conventional protection methods—such as fundamental voltage protection, third-harmonic voltage saturation, and low-frequency injection—lack fault location capability and cannot assess the fault severity. This paper proposes a stepwise variable-frequency pulse injection method for fault diagnosis and location in large hydro-generator stator windings. A finite element model of a salient-pole hydro-generator is established to analyze magnetic flux density and electromotive force distributions under normal and fault conditions, from which fault characteristics are derived. Equivalent circuit models suitable for low- and high-frequency pulse injection are developed. A bidirectional pulse injection circuit and algorithm are designed to identify the fault phase via terminal current vector characteristics, diagnose the faulty branch based on leakage loop equivalent inductance, and locate the fault point using voltage–current signal slopes. Simulation results validate the effectiveness of the proposed diagnostic approach. Full article

Late spring frosts and transient cold spells constrain tomato productivity. This study presents a comparative analysis of the chilling response of two Solanum lycopersicum cultivars, MoneyMaker (MM) and Micro-Tom (MT), and the wild relative S. lycopersicoides. The assessment integrated physiological parameters, such as electrolyte leakage and PSII efficiency, expression levels of CBF1–3 genes (via qPCR), and fatty acid composition dynamics of membrane lipids (via gas-liquid chromatography-mass spectrometry). The results revealed distinct response strategies. S. lycopersicoides exhibited comprehensive tolerance and was coordinated across biological levels. Its key mechanisms include superior membrane integrity, sustained PSII photochemical efficiency, stable upregulation of CBF genes (with predominant CBF3 induction), and consistently high α-linolenic acid content. This integration prevented membrane damage and sustained photosynthesis. Conversely, the MM cultivar displayed high sensitivity, characterized by transient CBF1 upregulation, an absence of adaptive lipid remodelling, rapid membrane damage, and severe photoinhibition, explaining its poor recovery. The MT genotype demonstrated an intermediate phenotype, featuring delayed but persistent CBF activation, and the partial lipid profile shifted toward the wild-type pattern, indicating a partial adaptive capacity for membrane adjustment. These findings establish S. lycopersicoides as a vital genetic resource for breeding cold-tolerant tomatoes, while MT provides a model for studying adaptation mechanisms in cultivated varieties. Full article

Streptozotocin (STZ) is an alkylating agent that has neurotoxic effects when injected into the cerebral ventricles (ICV) and also models many other features of Alzheimer’s disease. However, the mechanisms of STZ neurotoxicity are not well understood. In this study, we hypothesized that some of the neurotoxic effects of STZ could be due to direct activities on brain endothelial cells and astrocytes, which are key in forming and supporting the functions of the blood–brain barrier (BBB), respectively. To test this hypothesis, we characterized the changes induced by STZ either in cultures of human-induced pluripotent stem cell (iPSC)-derived brain endothelial-like cells (iBECs), which form an in vitro BBB model, or in primary human astrocytes. We found that STZ at a dosage of 5 mM caused a delayed reduction in the transendothelial electrical resistance (TEER) of iBECs at 7–11 days post-treatment, indicating induction of BBB leakage. Additionally, we observed significant increases in albumin leakage across the monolayer, altered iBEC morphology, and reductions in tight junction proteins, suggesting that STZ causes BBB disruption. We further found that the BBB glucose transporter GLUT-1 was reduced in iBECs, as was the total number of iBECs. In astrocytes, the 5 mM dose of STZ reduced the GFAP signal and total number of cells, suggesting that STZ has anti-proliferative and/or toxic effects on astrocytes. Together, these data support that STZ’s neurotoxic effects could be due, in part, to its direct toxic activities on brain endothelial cells and astrocytes. Full article

Steel-reinforced thermoplastic pipe is widely used for water transportation in sour gas fields. However, under the combined effects of corrosive media, internal high pressure, and long-term environmental aging, premature failures such as leakage and bursting often occur. To clarify the failure causes and primary contributing factors of the composite pipes, this study conducted a comprehensive analysis through microscopic morphology examination of different typical failure cases, differential scanning calorimetry, Fourier transform infrared spectroscopy, and mechanical property testing. The main failure mechanisms were investigated, and targeted protective measures are proposed. Key findings reveal that the typical failure modes are ductile cracking, aging-induced brittle cracking, and aging creep cracking. These failures follow a mechanism of degradation of the inner and outer polyethylene protective layers, penetration of the medium and corrosion of the steel wires, reduction in pressure-bearing capacity, and eventual structural damage or leakage propagation through the pipe wall. Notably, oxidation induction time values dropped as low as 1.4–17 min—far below the standard requirement of >20 min—indicating severe antioxidant depletion and material aging. The main controlling factors are poor material quality, external stress or mechanical damage, and long-term aging. The polyethylene used for the inner and outer protective layers is critical to the overall pipe performance; therefore, emphasis should be placed on evaluating its anti-aging properties and on protecting the pipe body during installation to ensure the long-term safety and stable operation of the pipeline system. Full article

Several industrial applications rely on induction motors to carry out processes essential for product manufacturing. Speed control of an induction motor commonly requires a pulse width modulated inverter capable of driving a system with long cables, suppression of common mode voltage, reduction in common mode current, and suppression of electromagnetic interference. This paper proposes a three-phase motor drive aimed at maintaining a constant common-mode voltage. The proposed system consists of two three-phase conventional full bridge inverters connected in parallel and having as an input two separate direct current sources. The proposed system is controlled by using the space vector pulse width modulation technique. By properly designing the switching signal sequences for both converters, the common-mode voltage can be maintained constant, thereby reducing the associated common-mode current to an RMS value of $92.3$ mA and enhancing the overall reliability of the system. The proposed system is validated through numerical simulations and by the implementation of an experimental prototype. Full article

Transformer-based models have accelerated EEG motor imagery (MI) decoding by using self-attention to capture long-range temporal structures while complementing spatial inductive biases. This systematic survey of Scopus-indexed works from 2020 to 2025 indicates that reported advances are concentrated in offline, protocol-heterogeneous settings; inconsistent preprocessing, non-standard data splits, and sparse efficiency frequently reporting cloud claims of generalization and real-time suitability. Under session- and subject-aware evaluation on the BCIC IV 2a/2b dataset, typical performance clusters are in the high-80% range for binary MI and the mid-70% range for multi-class tasks with gains of roughly 5–10 percentage points achieved by strong hybrids (CNN/TCN–Transformer; hierarchical attention) rather than by extreme figures often driven by leakage-prone protocols. In parallel, transformer-driven denoising—particularly diffusion–transformer hybrids—yields strong signal-level metrics but remains weakly linked to task benefit; denoise → decode validation is rarely standardized despite being the most relevant proxy when artifact-free ground truth is unavailable. Three priorities emerge for translation: protocol discipline (fixed train/test partitions, transparent preprocessing, mandatory reporting of parameters, FLOPs, per-trial latency, and acquisition-to-feedback delay); task relevance (shared denoise → decode benchmarks for MI and related paradigms); and adaptivity at scale (self-supervised pretraining on heterogeneous EEG corpora and resource-aware co-optimization of preprocessing and hybrid transformer topologies). Evidence from subject-adjusting evolutionary pipelines that jointly tune preprocessing, attention depth, and CNN–Transformer fusion demonstrates reproducible inter-subject gains over established baselines under controlled protocols. Implementing these practices positions transformer-driven BCIs to move beyond inflated offline estimates toward reliable, real-time neurointerfaces with concrete clinical and assistive relevance. Full article

For an induction motor operating as a symmetric three-phase system, the performance of indirect field-oriented vector control relies heavily on the accuracy of the rotor time constant. Any inaccuracies result in severe torque errors and compromise dynamic performance because of the coupling between the flux and torque controls. Although conventional IFOC methods are intended to compensate for the rotor time constant error, they rely on induction machine parameters such as the mutual and leakage inductances. This paper proposes an online method for tuning the rotor time constant independent of other parameters. First, an active power model of three-phase symmetric induction motor is selected to estimate the stator resistance based on a model reference adaptive system, which requires only the rotor time constant. Additionally, high-frequency current injection and torque ripple estimation without phase delay or amplitude decay are introduced to compensate for the rotor time constant. When a high-frequency current is injected, the rotor time constant and stator resistance can be simultaneously tuned without depending on other parameters. A high-frequency current is injected only when a rotor time constant error is detected from the estimated stator resistance. This behavior is enabled by the correlation between the stator resistance and the rotor time constant. Simulation results using MATLAB/Simulink regarding the symmetric three-phase induction motor validate the proposed method. Full article