Search Results (110,780)

Lightning discharges over the Tibetan Plateau are monitored by ground-based networks that locate radiation sources from their low-frequency radio emissions. This study uses the Qinghai Datong network in the northeastern Tibetan Plateau, which records the 50 kHz to 2.5 MHz band over a small area to locate lightning in three dimensions. In such networks, the accuracy of three-dimensional location depends critically on the consistency of the signals recorded across stations, which is progressively degraded by aging analog front-ends and by complex electromagnetic noise. To address this, we propose a phase-preserving denoising scheme, termed WZ, that suppresses both broadband and narrowband noise while keeping the relative timing between stations essentially unchanged, so that the arrival times used for location are preserved. The improvement is illustrated with both simulations and real data. In Monte Carlo simulations, WZ improves the signal-to-noise ratio by 10 dB and reduces the time-of-arrival error to 0.3 μs. Applied to two intracloud flashes of contrasting morphology, WZ recovers substantially more radiation sources and more continuous discharge channels than conventional filtering, at no cost to fit quality, allowing, for example, the downward development of the channel to be tracked quantitatively. The method requires no change to the existing hardware and can be applied to archived data, making it a practical way to improve both current and historical records from long-running low-frequency lightning networks. Full article

The absorber layer thicknesses of tandem photovoltaic devices containing hybrid organic–inorganic lead halide perovskite absorbers are optimized under AM 1.5 and AM 0 solar irradiance using external quantum efficiency (EQE) simulations. Using the EQE modeling approach derived from analysis of ellipsometric spectra collected from complete single-junction perovskite, all-perovskite tandem, and copper indium gallium diselenide (CIGS) thin film solar cells, structural–optical models are developed for two high-efficiency tandem solar cell configurations from their published EQE spectra. These configurations include a superstrate all-perovskite device and a substrate perovskite/CIGS device. These models serve as realistic and practical baselines for optimizing device performance under different circumstances. By increasing the thicknesses of an all-perovskite tandem superstrate device’s wide E_g and narrow E_g absorber layers from 350 and 975 nm to 356 and 1200 nm, the J_sc may be increased from 15.81 to 15.94 mA/cm² under AM 1.5 illumination. This corresponds to a potential increase in efficiency from 25.83 to 26.05% when using reported open circuit voltage (V_oc) and fill factor (FF). Under AM 0, an increase in absorber layer thickness to 310 and 1200 nm increases the J_sc from 18.56 to 19.72 mA/cm², which corresponds to an increase in efficiency from 30.33 to 32.22%. By increasing the thickness of the perovskite layer in a perovskite/CIGS substrate device from 500 to 615 nm, the J_sc may be increased from 18.84 to 19.65 mA/cm² assuming AM 1.5 illumination. This change would increase efficiency from 23.74 to 24.76%. Under AM 0 illumination, an increase in the perovskite thickness to 512 nm results in an increase in predicted J_sc from 23.13 to 23.34 mA/cm². This corresponds to a predicted efficiency increase from 29.15 to 29.41%. This modeling approach provides a stable platform for practical evaluation of different superstrate and substrate design tandem solar cells with perovskite semiconductors as at least one of their absorber layers. Full article

Tension-leg platform (TLP) horizontal-axis wind turbines (TLP-HAWTs) have become increasingly important in deep-water offshore wind energy development. However, their performance is strongly affected by coupled platform motions induced by wind and wave loads, making fully coupled simulations a critical prerequisite for accurate performance assessment. Conventional fully coupled approaches often struggle to balance computational efficiency and numerical fidelity. In this study, a simplified sequential coupled modeling framework is proposed based on the commercial solvers OrcaFlex and STAR-CCM+. In this framework, OrcaFlex is employed to simulate the hydrodynamic response of the floating platform, and the resulting platform motions are subsequently imposed as prescribed inputs in high-fidelity CFD-based aerodynamic simulations. Based on the proposed framework, a series of case studies of a 15 MW TLP-HAWT are conducted to investigate the effects of wind-induced and wave-induced platform motions on aerodynamic performance. The results indicate that wind-induced platform motions have a negligible impact on local inflow conditions and vortex intensity, and their influence on mean blade loads and wake topology can be safely ignored under rated conditions. In contrast, wave-induced motions significantly enhance unsteady aerodynamic loads, intensify vortex shedding, alter torque distribution along the blades, and increase wake turbulence intensity as well as velocity deficit. These findings suggest that wave-induced platform dynamics dominate the unsteady aerodynamic response and wake evolution of TLP-HAWTs under rated conditions, while wind-induced motions play a secondary role. The results provide valuable insights for reduced-order modeling, control strategy development, and the design optimization of efficient floating offshore wind turbines. Full article

Terahertz (THz) fingerprint spectroscopy enables label-free identification of molecular vibrational signatures, but trace biomolecular absorption is too weak to be reliably resolved in free-space measurements. To address this limitation, we propose a four-degree-of-freedom geometrically encoded THz metasurface for broadband multichannel fingerprint sensing. The substrate-free self-supporting aluminum structure incorporates four independently tunable geometric parameters: gap angle θ, outer ring radius R, scaling factor S, and ring width W. By regulating these parameters, multiple resonance-tuning pathways are established, enabling designable multiband spectral coverage over 0.6–1.4 THz and flexible matching with the fingerprint bands of L-hydroxyproline (L-HYP). Numerical simulations show that the metasurface achieves a refractive-index sensitivity of 512.66 GHz/RIU with a linear fitting coefficient of R² = 0.99708 and a mean Q factor of 4.72. For biomolecular fingerprint sensing, the encoded resonances overlap with the L-HYP absorption bands near 0.73 and 1.17 THz, producing AIT-like spectral modulation and envelope-derived attenuation enhancement. Compared with an unstructured analyte reference, the valid 0.73 THz readout gives enhancement factors of 5.76 and 7.09 for the R and S channels, respectively, while the four encoded channels provide enhancement factors of 3.53–4.45 at 1.17 THz. This design provides a compact strategy for broadband multichannel THz fingerprint enhancement, offering a promising route for monitoring collagen-metabolism-related biomarkers and advancing label-free biochemical sensing, fibrosis-related molecular screening, and integrated broadband THz detection. Full article

Tendon-cable transmission can reduce distal-limb inertia in full-size humanoids, but its elasticity, hysteresis, backlash, and multi-joint coupling introduce state-dependent joint-to-motor discrepancies. We present a hierarchical whole-body tracking framework for the 28-DoF Droid X3 that separates high-level motion learning from transmission compensation. A reference-residual policy is trained in simulation by single-stage proximal policy optimization (PPO) using a unified robot-space motion representation, globally anchored tracking rewards, hierarchical hard-example sampling, and tendon-oriented domain randomization. In simulation checkpoint evaluation, more than 90% of 12,674 tested reference motions are completed. Independently, a state-conditioned mapper is trained offline through a differentiable motor–joint forward model identified from physical motor-excitation data and connected in series between the frozen policy and the low-level motor controller. Randomized repeated Mapping-OFF/ON trials are conducted on two nominally identical Droid X3 units. Within every robot–motion block, the frozen PPO checkpoint, reference trajectory, controller settings, safety bounds, and frozen mapper weights are held fixed; complete trials are the statistical units. OFF converts desired joint positions with the robot-specific fixed static calibration, whereas ON feeds the complete policy-level desired-joint vector and measured plant state to the frozen mapper, which directly outputs the complete motor-position command. Across the complete physical trials, the aggregate action-completion rate is 68% with Mapping OFF and 79% with Mapping ON, an increase of 11 percentage points. Representative walk, squat, and dance trajectories illustrate lower tracking errors under Mapping ON, while individual frames and selected temporal fragments are used only for visualization. Full article

The development of simulated-solar-light photocatalysts for methyl orange (MO) removal is limited by insufficient light utilization, rapid photogenerated charge recombination, and restricted interfacial reaction sites. Here, vertically aligned ZnO nanorods on a conductive nanoporous Cu (NPCu) scaffold were modified with low-abundance RE-containing surface species (RE = Ce, Sm, Er, Tm, and Yb). The notation RE(OH)₃@ZnO/NPCu is retained solely as an operational sample identifier and does not constitute a crystallographic or stoichiometric phase assignment. XRD resolves the ZnO/NPCu framework, EDS confirms the local presence of RE, and XPS identifies RE-dependent oxidation state and surface oxygen environments; collectively, these measurements do not uniquely establish RE(OH)₃ or distinguish hydroxide from oxide, oxyhydroxide, and other hydroxylated/adsorbed surface configurations. The distinguishing feature is a controlled five-RE comparison on one common ZnO/NPCu architecture, together with separate evaluation of NPCu under H₂O₂-free and H₂O₂-assisted conditions. Across three independent H₂O₂-free runs, the Er-modified sample achieved 96.61 ± 0.30% MO degradation within 9 min with k_obs = 0.3930 ± 0.0071 min⁻¹. Dosage screening identified 20 μL of 40 wt% H₂O₂ in 20 mL MO solution (approximately 13.5 mM) as a practical plateau dosage. Photolysis, dark, NPCu/H₂O₂, and catalyst-removal controls support an additional solid-catalyst-dependent Cu-associated peroxide contribution while not excluding trace homogeneous reactions. Three independent cycling experiments and post-cycle SEM/XRD/EDS support operational durability, although quantitative metal leaching was not measured. Tauc, Mott–Schottky, EIS, temperature-dependent kinetic, and scavenger results are interpreted as comparative descriptors or indirect evidence rather than direct proof of intrinsic band gaps, atom-specific carrier densities, or a unique microscopic mechanism. The AI-assisted component is restricted to exploratory contextualization because reference-grouped validation shows poor out-of-reference generalization. The conclusions are confined to the tested MO system. Full article

Functional fermented foods are increasingly recognized as sources of microbial metabolites with potential biological activity. In this study, MRK2-3, a protease-sensitive anti-Helicobacter pylori component produced by Lactiplantibacillus pentosus MRK2-3 isolated from fermented mushroom sausage, was enriched and preliminarily characterized for in vitro anti-H. pylori activity. Activity appeared during the stationary phase. Sequential ethyl acetate extraction, Sep-Pak C18 chromatography, and reverse-phase HPLC increased specific activity, although the final activity recovery was 0.72%. MALDI-TOF analysis of the active fraction showed a dominant ion at approximately m/z 1848 together with several lower-intensity ions; therefore, chemical homogeneity and sequence identity were not established. The MRK2-3 fraction retained activity after incubation at pH 2–6 and after heating at 80 °C and 100 °C for 30 min, whereas activity decreased under alkaline conditions and after treatment at 121 °C for 15 min. Trypsin, α-chymotrypsin, pepsin and proteinase K reduced activity. The fraction inhibited all tested H. pylori strains (agar-dilution MIC ranged from 12.5 to 100 μg/mL). In a simulated gastric fluid, higher concentrations produced a rapid reduction in viable H. pylori 3949 counts. These findings support MRK2-3 as a fermentation-derived putative antimicrobial peptide candidate with anti-H. pylori activity under gastric-like conditions. However, its amino acid sequence, structural identity, and novelty require confirmation. Antimicrobial mechanism, cytotoxicity, and in vivo efficacy also remain to be established. Full article

Today, the use of increasingly ubiquitous synthetic media, or ‘deepfakes’, has become a risk to online trust, information integrity and individual security and is being created by artificial intelligence (AI). The current approaches are mainly based on either spatial features of CNNs or high-level semantic representations of Vision Transformer; both have major drawbacks in effectively leveraging multi-domain forensic cues. This paper presents FAViT (Frequency-Aware Vision Transformer), a hybrid architecture capable of jointly utilizing spatial- and frequency-domain forensic information by the means of a bidirectional cross-attention fusion scheme. We use an 11-channel forensic tensor in each face image (including per-channel Fast Fourier Transform (FFT) magnitude maps, Discrete Wavelet Transform (DWT) sub-bands, channel noise residual maps, Sobel gradient magnitude and channels of Error Level Analysis (ELA)). A Frequency Branch CNN processes this multi-domain tensor and the original RGB image is encoded with a pretrained ViT-B/16 spatial branch. The two streams are combined through the bidirectional cross-attention which allows the model to localize both spatial and spectral manipulation artifacts. We also present an adversarial cleaning simulation pipeline which partitions the training process with five post-processing attack methods, namely GFPGAN neural face restoration, learned autoencoder cleaning, etc., to increase resistance to real-world forensic defenses. Tests of FaceForensics++ C23 (7926 images, consisting of four manipulation types) show that FAViT attains F1-score of 86.22, AUC-ROC of 94.26 and accuracy of 85.55 on the held-out test set. The strength analysis of 21 attack conditions shows that the max degradation in AUC is 30.3, with specific strengths in GFPGAN restoration (AUC = 98.51). Robustness is evaluated based on 21 post-processing attack cases that include JPEG compression, Gaussian blurring, down-sampling, and GFDGAN neural-based restoration; it should be noted that robustness against gradient-based adaptive attacks requires additional attention. Testing on the CIFAKE and Celeb-DF v2 datasets reveals some limitations of domain generalization. Full article

This work constitutes Part III of a comprehensive three-part study that critically reviews techniques for the indirect extraction of the thermal resistance in bipolar transistors using simple DC current/voltage measurements. While Part I focused on thermometer-based methods and Part II examined approaches relying on intersection points between characteristics, this paper mainly investigates techniques exploiting the base current. Their accuracy is assessed by applying them to DC electrothermal characteristics obtained through circuit simulations of an in-house transistor model incorporating nonlinear thermal effects and comparing the extracted thermal resistance data with the formulation embedded in the model. An InGaP/GaAs HBT and a Si/SiGe HBT for high-frequency applications are considered as case studies. The analysis highlights the accuracy, advantages, and limitations of the examined approaches, discussing the impact of theoretical approximations and physical mechanisms. In addition, the analytical method proposed by Menozzi et al. is critically evaluated within the same simulation framework. Overall, the results show that none of the examined techniques provides a universally applicable, straightforward, and robust extraction procedure, since each involves theoretical assumptions and/or practical constraints that restrict its range of validity, numerical robustness, or ease of application. Finally, the findings from all three parts of this study are summarized, and practical guidelines are provided to support the selection and correct application of extraction techniques. Full article

To effectively address the challenges of complex spatiotemporal conflicts, dynamic obstacle avoidance, and coordinated multi-objective optimization in preemptive multi-UAV logistics delivery within complex airspace, this study proposes a Hybrid Improved Multi-Objective Cuckoo Search algorithm (HI-MOCS) for preemptive multi-UAV cooperative logistics scheduling and planning. To overcome the limitations of conventional MOCS, including a low proportion of feasible solutions under complex constraints, susceptibility to local optima, and uneven distribution of multi-objective solution sets, a multi-constraint physical model and a multidimensional evaluation framework are established for preemptive scheduling. A positive knowledge-transfer mechanism based on the co-evolution of primary and auxiliary populations is developed, in which constraint-violation information is used to guide infeasible solutions toward the feasible region. A hybrid heuristic population initialization strategy combining emergency-order priority and spatial scanning rules is introduced to increase the proportion of high-quality feasible solutions in the initial population. In addition, a nonlinear dynamic adaptive parameter-adjustment strategy is designed to balance global exploration and local exploitation, while an iterative truncation-based environmental selection mechanism using the shortest-distance criterion is employed to improve the distribution quality of the Pareto solution set. The experimental results show that, in the benchmark scenario, HI-MOCS achieves an average increase of 33.26% in the total order completion rate and an average reduction of 15.34% in emergency response time compared with 11 multi-objective optimization algorithms, while also exhibiting favorable performance in terms of flight distance per completed order. The fleet-size analysis shows that the 15-UAV configuration achieves the lowest best mean fitness. The safety-distance analysis indicates that, compared with the other safety-distance settings, the 30 m setting increases the total order completion rate by an average of 26.55%, while reducing emergency response time and flight distance per completed order by 27.36% and 33.72%, respectively. The task-scale analysis shows that the 50-order scenario achieves the lowest best mean fitness. Further ablation experiments demonstrate that, compared with the average performance of MOCS and the four single-strategy variants, the complete HI-MOCS improves the total order completion rate by 20.27%, while reducing emergency response time and flight distance per completed order by 20.71% and 36.18%, respectively. The HV, IGD, and Pareto-front results further confirm that the synergistic effects of the four improvement mechanisms effectively enhance the multi-objective optimization performance and the quality of the nondominated solution set. The current study is still validated under simulation conditions assuming reliable GNSS positioning and communication links, without explicitly considering communication delays. Full article

This paper presents a numerical analysis of liquefaction-induced lateral spreading at Brest Pokupski in Croatia, observed during the 2020 M_w6.4 Petrinja earthquake. The site is composed of Holocene alluvial deposits consisting of loose to medium-dense sands, silty sands, and sandy silts with high groundwater levels, locally confined by low-permeability cohesive layers, which together created favourable conditions for excess pore pressure generation, liquefaction and lateral spreading. During the 2020 Petrinja earthquake, the area experienced large-scale ground failures, including widespread soil deformations, sand ejecta, ground cracking and settlement, making it one of the most prominent manifestations of earthquake-induced liquefaction in the affected region. The study applies dynamic analyses using the advanced constitutive models and soil parameters derived from laboratory tests and CPT investigations. The model simulates excess pore water pressure development and resulting ground deformations, with displacements evaluated at advanced stages of dissipation. During the dissipation phases, the model exhibits a high sensitivity to hydraulic conductivity, which may be attributed to slight residual numerical imbalances at the end of shaking. Consequently, scaling factors of 100 and 1000 result in horizontal displacements of approximately 20–30 cm and 60–70 cm, respectively, within the liquefiable layer. Trends of ground displacement with distance along the profile, however, remain consistent regardless of the applied scaling factors, and can therefore be used in conjunction with displacement measurements to assess the response. Numerical results are used in conjunction with InSAR observations from the European Ground Motion Service (EGMS) and geodetic benchmark measurements to assess the displacement field changes along the profile. The comparison from two points showed a shift in the displacement direction towards the river by about 14^∘. Full article

To identify severe missing events in low-voltage distribution network (LVDN) measurements under coexisting errors and asynchrony, a label-free severe missing event detection method based on the mean shift test is proposed. First, mathematical models for the error rate, asynchrony rate, and missing rate are established to describe typical gray measurement data scenarios in LVDNs, where errors and asynchrony are treated as background disturbances. Second, a phase-specific current regression model for severe missing-event detection is constructed based on the multiple linear relationship between the phase-line head-end current and the customer-side currents. Then, the mean shift test is introduced to detect abnormal time snapshots caused by severe missing events through statistical hypothesis testing. Simulation results show that the proposed method achieves a high TPR while maintaining a low FPR in the main comparative experiments, and it achieves the best overall TPR–FPR trade-off among the evaluated methods. The results demonstrate that the proposed method provides an effective means for label-free detection of severe missing events in LVDNs under background measurement disturbances and the operating conditions considered in this study. Full article

This systematic review synthesises computational models of language deficits in bilingual aphasia, focusing on code-switching and translation. Per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, this study identified 42 publications (2010–2025). Of the three deficit types, lexical retrieval and naming deficit simulations are most mature, replicating naming errors and predicting cross-language generalisation. Code-switching and translation deficit modelling is extremely limited: only a single computational lesioning study has addressed both through mechanistic simulation. Machine learning methods show preliminary promise for predicting treatment outcomes but remain largely data-driven. Three key challenges emerge: (1) methodological fragmentation—heterogeneous model types, lesion implementations, and evaluation metrics, with no standardised quantitative validation; (2) an underdeveloped theoretical foundation, as most studies are confined to behavioural fitting rather than testing hypotheses on impaired language control via computational lesions; (3) limited clinical translation, with few predictive studies integrating longitudinal patient data, with approximately 70% of studies concentrated in North America/Western Europe and biased toward English–Spanish bilinguals, limiting theoretical generalisability. Future work should shift from behavioural fitting to explainable mechanistic simulation, develop predictive frameworks for personalised rehabilitation, and establish standardised protocols bridging computational modelling with clinical application. Full article

Although the Pacific oyster (Crassostrea gigas) is a premium marine protein source, its neuroprotective peptidome remains largely uncharacterized. This study established an integrated in silico and in vitro pipeline to discover acetylcholinesterase (AChE)-targeting peptides with cellular AChE-regulating and neuroprotective peptides from simulated gastrointestinal digests of oyster. Peptidomic profiling identified 18,292 sequences, which were filtered down to seven candidates predicted to have favorable blood–brain barrier (BBB) permeability and to be non-toxic and non-allergenic (VPYPR, VPVHF, HHTF, PVHF, GPKPW, HWF, and KYW) via multi-step virtual screening. In cellular assays, simulated H₂O₂ injury (500 μM) reduced PC12 cell viability to 47.53 ± 4.53%. Compared with the model group, pretreatment with the three most potent candidates—HHTF, VPYPR, and VPVHF (200 μM)—significantly rescued injured cells, restoring cell viability to 88.31 ± 7.83%, 85.12 ± 3.35%, and 82.00 ± 3.47%, respectively (p < 0.05). These peptides effectively fortified cellular antioxidant defenses by increasing glutathione (GSH) levels to 24.24, 30.11, and 26.83 nmol/mg protein (from 20.22 nmol/mg protein in the model group) and superoxide dismutase (SOD) activity to 151.41, 153.97, and 151.96 U/mg protein (from 119.33 U/mg protein), while suppressing malondialdehyde (MDA) accumulation to 0.088, 0.064, and 0.086 nmol/mg protein (from 0.193 nmol/mg protein). Crucially, the peptides alleviated cholinergic dysfunction by normalizing the H₂O₂-induced elevation of intracellular AChE activity (11.39 nmol/min/mg protein) down to 7.02, 6.22, and 7.14 nmol/min/mg protein, respectively. Specifically, VPYPR (200 μM) restored AChE activity to a level (6.22 nmol/min/mg protein) that was not significantly different from that in the normal control group (p > 0.05). Molecular dynamics (MD) simulations (100 ns) and molecular mechanics Poisson–Boltzmann surface area (MM-PBSA) calculations identified VPYPR as the leading candidate with a remarkably low binding free energy of −49.74 ± 3.58 kcal/mol. This study demonstrates that oyster gastrointestinal digests are valuable reservoirs of multi-target neuroprotective ingredients and provides an efficient strategy for marine bioactive peptide discovery. Full article

Intermediate band solar cells require in-gap electronic states that remain sufficiently extended to sustain collective electronic coupling and facilitate carrier motion. We investigate how structural disorder affects an intermediate band formed by coupled colloidal quantum dots embedded in a perovskite-like matrix. The system is represented by a single-orbital tight-binding Hamiltonian on a dilated face-centered-cubic lattice containing 4000 quantum dots, with system sizes between 1372 and 5324 in the finite-size analysis. Radius dispersion modifies on-site energies and hopping amplitudes, whereas positional disorder acts mainly through variations in interdot separation. Eigenstate extension is quantified using the normalized participation ratio. To distinguish spectral broadening from the loss of useful extended states, we also evaluate the mean participation of a contiguous threshold-defined spectral core, its relative energy width, and their product as a combined robustness descriptor. For the adopted baseline parameter set, degradation is energy selective: states near the spectral edges lose participation before states near the band center. At equal nominal amplitudes, radius disorder produces a stronger response than positional disorder, although the two amplitudes do not represent equal realized variances. A positional-disorder amplitude of 0.05 retains approximately 86% of the ordered-reference value of the combined descriptor, whereas a radius-disorder amplitude of 0.05 reduces it to about 22%; when both amplitudes are 0.05, about 14% remains. The model displays a comparatively robust regime near ${\sigma }_R=0.02$, a model-dependent crossover around ${\sigma }_R=0.03$–$0.04$, and strong degradation at larger values. Finite-size results are consistent with near-extensive scaling of the effective core participation number over the simulated sizes, but do not establish a thermodynamic mobility edge. These findings identify quantum-dot size uniformity as the more restrictive model control variable for preserving an extended intermediate-band core. Full article