Search Results (1,033)

Constructing van der Waals heterojunctions with excellent properties has attracted considerable attention in the field of photocatalytic water splitting. In this study, four patterns, coined A, B, C, and D of Janus Ga₂SSe/Bi₂O₃ van der Waals (vdW) heterojunctions with different stacking modes, were investigated using first-principles calculations. Their stability, electronic structure, and optical properties were analyzed in detail. Among these, patterns A and C heterojunctions demonstrate stable behavior and operate as direct Z-scheme photocatalysts, exhibiting band gaps of 1.83 eV and 1.62 eV. In addition, the suitable band edge positions make them effective for photocatalytic water decomposition. The built-in electric field across the heterojunction interface effectively inhibits electron-hole recombination, thereby improving the photocatalytic efficiency. The optical absorption coefficients show that patterns A and C heterojunctions exhibit higher light absorption intensity than Ga₂SSe and Bi₂O₃ monolayers, spanning from the ultraviolet to visible range. Their corrected solar-to-hydrogen (STH) efficiencies are 13.60% and 12.08%, respectively. The application of hydrostatic pressure and biaxial tensile strain demonstrate distinct effects on photocatalytic performance: hydrostatic pressure preferentially enhances the hydrogen evolution reaction (HER), while biaxial tensile strain primarily improves the oxygen evolution reaction (OER). Furthermore, the heterojunctions exhibited enhanced optical absorption across the UV-visible spectrum with increasing hydrostatic pressure. Notably, a 1% tensile strain results in an improvement in visible light absorption efficiency. These results demonstrate that Ga₂SSe/Bi₂O₃ heterojunctions hold great promise as direct Z-scheme photocatalysts for overall water splitting. Full article

Space charge injection in polypropylene (PP) significantly weakens the stability of HVDC cables. Impact polypropylene copolymer (IPC) is often used as insulation material for AC cables, but in the DC field, IPC has the problem of space charge accumulation. This is because there is a multi-phase structure inside the IPC to which ethylene monomer was added in the production process, and the difference in physicochemical properties of each phase is an important reason for the accumulation of space charge inside the material. In this work, the vinyl phases and propenyl phases of two types of IPC were separated. The film samples were prepared and tested at 30 °C and 50 °C for DC electrical conductivity, and at 30 °C, 50 °C, and 80 °C for space charge. The experimental results show that the DC conductivity of vinyl phases is significantly higher than that of propenyl phases in both types of IPC. The degrees of mismatch between the DC conductivity of vinyl phase and that of propenyl phase are different in the two types of IPC, and the mismatch degree of DC conductivity is from several times to hundreds of times. The conductivity of the two vinyl samples is ohmic. The conductivity of the two propenyl phases shows nonlinearity under different electric field intensity, and the mismatch degree of the two phases increases with temperature. Compared to untreated IPC, at all test temperatures, the maximum space charge density of the propenyl samples is much lower, which can be reduced by about 1/3 at 50 °C and by about 50% at 80 °C. The density of heteropolar charge produced by impurity ionization in the samples and the depth of electrode injection both decreased. At each temperature, the distortion rate of the electric field in propenyl samples is lower than that in IPC, the distortion rate can be reduced by more than 15%, and the distortion rate can be reduced by nearly half at 80 °C. The charge dissipation characteristic of propenyl samples during depolarization is also optimized compared with IPC samples, the time required for charge dissipation to reach stability is shortened, and the residual charge density in the sample is reduced at the end of depolarization. In addition, the relevance between the variation of DC conductivity of phases and space charge characteristics was discussed according to SCLC (space charge limited current) theory. This work provides a feasible reference for the manufacture of high-reliability polypropylene-based cable material with excellent insulation performance. Full article

HVDC cable systems are becoming an upscaled technical option, compared to AC, because of various factors, including easier interconnections, lower losses, and longer transmission distances. In addition, renewables providing direct DC energy, electrified transportation, and aerospace where DC can be favored because of higher carried specific power all point in the direction of broad future usage of HV and MV DC links. However, contrary to AC, there is little return from on-field installation as regards long-term cable reliability and aging processes. This gap must be covered by intensive research, and contributing to this research is the purpose of this paper. The focus is on key points for HVDC (and MVDC) cable reliability and sustainability, from design modeling able to account for voltage transients and extrinsic aging (such as that caused by partial discharges) to the impact of aging on insulation conductivity (which rules the electric field distribution, thus aging rate). Also, recyclable and nanostructured materials, as well as health conditions, are considered. It is shown how cable design can account for accelerated aging due to voltage transients, as well as for aging-time dependence of conductivity, and how design can be free of extrinsic aging caused by PDs. Algorithms for health condition evaluations, which have additional value in a relatively new technology such as HVDC polymeric cables, are applied to insulation system aging under partial discharges, showing how they can provide an indication of insulation degradation globally or locally (weak spots) and of possible maintenance times. All of this can effectively contribute to reducing the risk of major cable breakdown and damage under operation, which would significantly affect the return on investment (ROI). Full article

The rapid growth of solar photovoltaic (PV) installations worldwide has increased the need for the effective monitoring and maintenance of these vital renewable energy assets. PV systems are crucial in reducing greenhouse gas emissions and diversifying electricity generation. However, they often experience faults and damage during manufacturing or operation, significantly impacting their performance, while thermal infrared imaging provides a promising non-invasive method for detecting common defects such as hotspots, cracks, and bypass diode failures, current deep learning approaches for fault classification generally rely on computationally intensive architectures or closed-source solutions, constraining their practical use in real-time situations involving low-resolution thermal data. To tackle these challenges, we introduce SlantNet, a lightweight neural network crafted to classify thermal PV defects efficiently and accurately. At its core, SlantNet incorporates an innovative Slant Convolution (SC) layer that utilizes slant transformation to enhance directional feature extraction and capture subtle thermal gradient variations essential for fault detection. We complement this architectural advancement with a thermal-specific image enhancement augmentation strategy that employs adaptive contrast adjustments to bolster model robustness under the noisy and class-imbalanced conditions typically encountered in field applications. Extensive experimental validation on a comprehensive solar panel defect detection benchmark dataset showcases SlantNet’s exceptional performance. Our method achieves a 95.1% classification accuracy while reducing computational overhead by approximately 60% compared to leading models. Full article

To mitigate the three-dimensional (3D) coupling interference of electric field sensors, a novel MEMS 3D electric field sensor with a dual-orthogonal induction structure and its spatial decoupling method is proposed. The sensor is designed with a cylindrical structure, in which two pairs of induction electrodes are orthogonally arranged to suppress common-mode interference. MEMS electric field sensing chips are utilized to achieve 3D electric field measurement. Furthermore, a spatial decoupling calibration model is established based on the structural characteristics of the sensor. The Cramér–Rao lower bound of the linear model is calculated to obtain the optimal decoupled calibration matrix, enabling precise 3D electric field decoupling. Experimental results showed that within an electric field range of 0–50 kV/m, the linearity of the three decoupled electric field components was 2.60%, 1.20%, and 1.78%, respectively, while the synthesized electric field achieved a linearity of 0.74% with a maximum full-scale error of 0.80%. Under varying angles and field intensities, the maximum and average relative errors of the decoupled synthesized electric field were 1.20% and 0.43%, respectively, representing reductions of 61.8% and 56.1% compared to the conventional matrix inversion method. These results confirmed that the proposed method effectively suppressed coupling interference and enhanced 3D electric field measurement accuracy. Full article

Cancer treatment has historically depended on conventional methods like chemotherapy, radiation, and surgery; however, these strategies frequently present considerable limitations, including toxicity, resistance, and negative impacts on healthy tissues. In addressing these challenges, drug-free cancer therapies have developed as viable alternatives, utilizing advanced physical and biological methods to specifically target tumor cells while reducing damage to normal tissues. This review examines several drug-free cancer treatment strategies, such as high-intensity focused energy beams, nanosecond pulsed electric fields, and photothermal therapy as well as the use of inorganic nanoparticles to promote selective apoptosis. We also investigate the significance of targeting the tumor microenvironment, precision medicine, and immunotherapy in the progression of personalized cancer therapies. Although these approaches demonstrate significant promise, challenges including scalability, safety, and regulatory obstacles must be resolved for clinical application. This paper presents an overview of current research in drug-free cancer therapies, emphasizing recent advancements, underlying scientific principles, and the steps required for clinical implementation. Full article

To address the severe gate-induced drain leakage (GIDL) issue in fully depleted germanium-on-insulator (FD-GeOI) multi-subchannel tunneling field-effect transistors (MS TFETs), this paper proposes a stepped gate oxide (SGO) structure. In the off-state, the SGO structure effectively suppresses GIDL by reducing the electric field intensity at the channel/drain interface while simultaneously decreasing gate capacitance to reduce static power consumption. Based on an accurate device model, a systematic investigation was conducted into the effects of varying the thickness and length of the SGO structure on TFET performance, enabling the optimization of the SGO design. The simulation results demonstrate that, compared to normal MS TFETs, the SGO MS TFET reduces the off-state GIDL current ($I_{\mathrm{off}}$) from $4.6\times {10}^{-7}$ A to $2.6\times {10}^{-11}$ A, achieving a maximum improvement of 4.22 orders of magnitude in the on-state-to-off-state current ratio ($I_{\mathrm{on}}/I_{\mathrm{off}}$) and a 28% reduction in subthreshold swing (SS). Furthermore, compared to lightly doped drain (LDD) MS TFETs, the SGO MS TFET achieves a 32% reduction in total gate capacitance and a 23% enhancement in carrier mobility at the channel/drain interface. This study demonstrates that SGO provides an effective solution for GIDL suppression. Full article

This paper presents the issues related to aging studies of electrical insulation in winding wires, which are widely used in electrical machines. Insulating materials in electrical machines are subjected to various stress factors, particularly electrical stress. The proper design of such insulation systems requires an understanding of the behavior of individual system components under specific operating conditions. This knowledge enables the optimization of insulation design, which can contribute to extending the operational lifespan of electrical machines. In this study, the results of experimental investigations on twisted-pair winding wires with different geometric dimensions, subjected to electrical stress (a square voltage waveform in the kilohertz frequency range) under different pressure conditions, are presented. The experimental research is supplemented by simulation-based calculations of the electric field intensity in the examined twisted-pair winding wire samples. Full article

Pediatric primary brain tumors pose significant therapeutic challenges due to their aggressive nature and the critical environment of the developing brain. Traditional modalities like surgery, chemotherapy, and radiotherapy often achieve limited success in high-grade gliomas and embryonal tumors. Tumor-treating fields (TTfields), a non-invasive therapy delivering alternating electric fields, has emerged as a promising approach to disrupt tumor cell division through mechanisms such as mitotic disruption, DNA damage, and tumor microenvironment modulation. TTfields are thought to selectively target dividing tumor cells while sparing healthy, non-dividing cells. While TTfields therapy is FDA-approved for the management of glioblastoma and other cancers, its application in pediatric brain tumors remains under investigation. Preclinical studies reveal its potential in medulloblastoma and ependymoma models, while observational data suggest its safety and feasibility in children. Current research focuses on optimizing TTfields’ efficacy through advanced technologies, including high-intensity arrays, skull remodeling, and integration with immunotherapies such as immune checkpoint inhibitors. Innovative device-based therapies like magnetic field-based technologies further expand the treatment possibilities. As clinical trials progress, TTfields and related modalities offer hope for addressing unmet needs in pediatric neuro-oncology, especially for tumors in challenging locations. Future directions include biomarker identification, tailored protocols, and novel therapeutic combinations to enhance outcomes in pediatric brain tumor management. Full article

A multi-vane and multi-slit electrospinning nozzle for diversion was proposed to respond to the issues of easiness of clogging, existing End Effect among needles in current multi-needle electrospinning, and uncontrollable Taylor cone position in needleless electrospinning. The upper part of the novel nozzle is a cylindrical straight pipe, and the lower part is a flow channel expansion structure composed of multiple vane components that spread outward at an angle. Ansys software was used to study the effect of different opening angles of the vanes on the spreading of the electrospinning solution. In the fluid simulation, for the novel nozzle with a central slit and a support structure, when the vanes have an opening angle of 35° and a length of 11 mm, the droplet holding time is 16 s, twice as long as the nozzle without support (8 s). This result corresponds to the subsequent droplet holding experiment, showing that the support structure aids droplet holding and enhances electrospinning stability. Comsol Multiphysics software was used to investigate the effect of the vanes’ parameters on the uniformity of the electric field. The results indicate that when the vanes of the new electrospinning nozzle are set at an opening angle of 35°, with four vanes each 11 mm in length, a receiving distance of 200 mm, and a voltage of 30 kV, the novel nozzle achieves an average electric field intensity of 5.26 × 10⁶ V/m with a CV value of 6.93%. Metal 3D printing was used to create a new nozzle for electrospinning, which successfully produced stable multiple jets and increased nanofiber output. Full article

Pulsed Electric Fields (PEFs) are a technology increasingly used in the food industry for various purposes. However, their potential benefits as a pretreatment prior to the culinary preparation of a product have rarely been investigated. No previous study has investigated the use of PEFs in obtaining gazpacho, a typical Spanish dish. We aimed to evaluate the possibility of applying this technology in pretreating the vegetables used in gazpacho; furthermore, we evaluated its impact on the final product by comparing results with control samples. Applied at several different intensities (0.5–1.5 kV/cm and 4–40 kJ/kg), PEFs softened and decreased the vegetables’ water-holding capacity. In addition, this technique beneficially affected the organoleptic characteristics of gazpacho, increasing its consistency, improving its color (which became more reddish and intense), and enhancing its flavor. Moreover, the use of PEFs allowed us to reduce the amount of water in the mix, thus saving natural resources, concentrating nutrients, and decreasing energy consumption. Although further studies are required, PEFs can be considered a technology of interest in this productive sector. Full article

Indium tin oxide (ITO) is a transparent conducting material with exceptional electrical and optical properties, widely used in biosensing and bioelectronics. Functionalization of ITO with linker molecules enables covalent attachment of biomolecules, allowing for dual-mode optical and electrochemical detection. Carbonic anhydrase IX (CA IX), a transmembrane enzyme overexpressed in hypoxic tumors, is a promising biomarker for cancer diagnostics due to its restricted expression in normal tissues. However, conventional detection methods are time-intensive and unsuitable for point-of-care applications. In this study, ITO surfaces were functionalized using silane-based chemistry to immobilize CA IX-specific antibodies, creating a novel biosensing platform. The biosensor utilized a secondary horseradish peroxidase (HRP)-conjugated antibody to catalyze the oxidation of luminol in the presence of hydrogen peroxide, producing a chemiluminescent and electrochemical signal. Characterization of the biosensor via a dual-mode optical and electrochemical approach revealed efficient antibody immobilization. Due to the high variation observed in the optical approach, limit of detection (LOD) experiments were conducted exclusively with electrochemistry, yielding an LOD of 266.4 ng/mL. These findings demonstrate the potential of ITO-based electrochemical biosensors for sensitive and selective CA IX detection, highlighting their applicability in cancer diagnostics and other biomedical fields. Full article

Transcranial electrical stimulation, as a means of neural modulation, is increasingly favored by researchers. The distribution and magnitude of the electric field generated within the brain may directly affect the results of neural modulation. Therefore, it is important to clarify the change trend of the cortical electric field and the determinants of the induced electric field in the endodermis at different ages during the adult life cycle. In this study, we used SimNIBS software to perform MR image segmentation and realistic head model reconstruction on 476 individuals (aged 18 to 88 years old) and calculated the cortical electric field of four electrode montages commonly used in cognitive tasks. We divided all participants into groups by age with a span of 10 years for each group and compared the electric field distribution patterns, electric field intensities, and focalities of the cortexes and regions of interest related to cognitive tasks within groups. The degree of influence of global and local anatomical parameters on the electric field was analyzed using a stepwise regression model. The results showed that, in the cortexes and regions of interest, the variability of electric field distribution patterns was highest in adolescents (<20 years old) and elderly individuals (>80 years old). Moreover, throughout the adult lifespan, the electric field induced by transcranial electrical stimulation did not decrease linearly with age but rather presented a U-shaped pattern. In terms of the entire adult life cycle, compared with global anatomical parameters (intracranial brain tissue volume), local anatomical parameters (such as scalp or skull thickness below the electrode) have a greater impact on the amplitude of the intracranial electric field. Our research results indicated that it is necessary to consider the effects caused by different brain tissues when using transcranial electrical stimulation to modulate or treat individuals of different ages. Full article

Gallium nitride (GaN), an advanced piezoelectric semiconductor, shows strong potential for ultraviolet (UV) applications due to its prominent thermoelectric, photoelectric, and mechanoelectrical coupling effects, all of which are critical to device performance. This paper focuses on one-dimensional GaN nanowires and introduces a nonlinear theoretical model to describe pyroelectric and photoelectron effects under UV excitation. The model accounts for both photothermal and photoconductive effects. Using the perturbation method, we derive an approximate analytical solution for the internal physical field of the nanowire under UV light irradiation, which aligns well with the results from nonlinear numerical simulations. Compared to a light intensity of 2 W/m², a light intensity of 6 W/m² leads to a 45% increase in electron concentration, a 235% rise in hole concentration, a 146% increase in potential, and a 274% increase in polarization charge concentration. The pyro-phototronic effect enables UV light to modulate the electrical transport characteristics of a Schottky junction. This study addresses the limitations of linearized models for handling large disturbances, providing a comprehensive theoretical and computational framework for advancing GaN micro- and nanoscale devices and enabling effective, non-contact control. Full article

In this study, a numerical simulation was used to evaluate the insulation performance of polyethylene (PE) and polyvinyl chloride (PVC) under varied environmental and electrical conditions. Tests were conducted at temperatures of 22 °C and 55 °C, with current levels of 40 A and 60 A, examining key parameters such as electric field intensity, current density, and Joule heating. The results show that, under lower temperature and current conditions, PE demonstrates greater current capacity but suffers from increased Joule heating and energy loss. Conversely, PVC provides more stable insulation with lower energy dissipation. At higher temperatures and currents, PE experiences significant electrical stress and thermal loading, increasing the risk of overheating, while PVC maintains consistent performance. These findings offer valuable guidance for selecting optimal insulation materials in power distribution systems. Full article