Search Results (440)

This study presents a comparative analysis of efficiency and harmonic generation in Triple Active Bridge (TAB) converters under two operating configurations: Case I, with one input source and two loads, and Case II, with two input sources and one load. Two modulation strategies, Single-Phase Shift (SPS) and Dual-Phase Shift (DPS), are evaluated through frequency-domain modeling and simulations performed in MATLAB/Simulink. The analysis is complemented by experimental validation on a laboratory prototype. The results show that DPS reduces harmonic amplitudes, decreases conduction losses, and improves output waveform quality, leading to higher efficiency compared to SPS. Harmonic current spectra and total harmonic distortion (THD) are analyzed to quantify the impact of each modulation method. The findings highlight that DPS is more suitable for applications requiring stable power transfer and improved efficiency, such as renewable energy systems, electric vehicles, and multi-source DC microgrids. Full article

Fish-derived collagen can reduce the risk of disease transmission and has no religious or cultural restrictions. However, it has limited applications due to its poor thermal stability. In this study, black carp swim bladder collagen (BBC), classified as a type I collagen, was extracted. Amino acid composition analysis revealed that BBC had a higher proline hydroxylation rate of 39.57%. Fourier transform infrared spectroscopy revealed that BBC exhibited a complete triple-helix structure. The fractional viscosity curve and differential scanning calorimetry curves revealed that the thermal denaturation temperature (Td) and the melting temperature (Tm) were 30.85 °C and 107.19 °C, respectively. The dynamic rheological analysis showed that as the concentration increased from 5 mg/mL to 20 mg/mL at 0.01 Hz, the storage modulus increased from 0.979 Pa to 84.2 Pa. When the temperature exceeded the Td, the BBC solution exhibited viscous behaviour as the frequency increased. The steady-shear analysis showed that the BBC was a shear-thinning fluid. Functional properties analysis revealed that BBC exhibited better emulsification properties, foaming properties, water absorption capacity and oil absorption capacity than land-derived collagen, making it suitable for emulsifiers, bubbling beverages, and frozen meat preservation. Additionally, BBC promoted the growth of MT3C3-E1 cells and maintained the normal morphology of the cells. These results showed that BBC is a promising substitute for terrestrial collagen in functional foods, cosmetics, and biofunctional materials. Full article

Background/Objectives: Although surgeries employing cone-beam computed tomography (CBCT) for small lung lesions have been reported, the association between CBCT scan frequency and patient radiation exposure remains unclear. This study aimed to investigate patient radiation doses from CBCT during thoracic surgeries, and the patient radiation doses were compared with those from other preoperative marking methods. Methods: This multicenter prospective study included 81 patients who underwent surgery for small lung lesions requiring marking between January 2021 and June 2024 at three institutions. CBCT-guided surgeries involved the use of metal clips in a hybrid operating room with 1–4 scans, depending on the lesion. For other preoperative marking methods, hook-wire or virtual-assisted lung mapping (VAL-MAP) was used. Patient radiation doses were measured using wearable dosimeters at five anterior thorax sites, and the total dose was compared across methods. Results: The study included 81 patients: CBCT (n = 61), VAL-MAP (n = 10), and hook-wire (n = 10). CBCT cases were distributed as follows: single scan (n = 10), double scans (n = 34), triple scans (n = 15), and quadruple scans (n = 2). The radiation doses were 86.9 ± 61.7 mGy for hook-wire, 39.8 ± 27.5 mGy for VAL-MAP, and 11.0 ± 6.5 mGy for single-scan CBCT, 17.3 ± 7.8 mGy for double scans, 23.1 ± 14.0 mGy for triple scans, and 22.7 ± 0.1 mGy for quadruple scans. Although radiation exposure increased with more CBCT scans, performing up to triple scans resulted in significantly lower exposure compared to other methods. Conclusions: Intraoperative CBCT is a feasible and safe technique for identifying small lung lesions, providing lower radiation exposure compared to other preoperative localization methods. Full article

Deep coal seams have low permeability and poor wettability, making gas extraction difficult. This study presents a zero-energy consumption pulsating water hammer fracturing technique that uses the gravitational potential energy of high-elevation water and the pulsating pressure waves from the water hammer effect to induce fatigue damage in coal, creating an interconnected network of cracks. The research included experiments on water hammer pressure waves, multi-physics field coupling simulations at different flow rates, and discrete element simulations to analyze the fracture behavior of underwater hammer pressure. Results showed that initial flow velocity impacts the water hammer pressure’s intensity, range, and duration. Pressure shock waves propagate as expansion and compression waves, with peaks rising from 4.99 to 19.91 MPa within a 2–12 m/s flow rate range. Water hammer pressure reduced fracture initiation pressure by 23% compared to static pressure loading and increased fracture numbers by 13.4%. With pressure amplitudes between 2–18 MPa, fractures tripled, and the damaged area grew from 2.2 to 11%. A variable frequency combination loading strategy, starting with low frequency and then high frequency, was more effective for fracture propagation. This study offers a theoretical foundation for applying this technology to enhance coal seam permeability and gas pumping efficiency. Full article

Continuous decrease in inertia and sensitivity to load/generation fluctuation are significant challenges for present-day power networks. The primary reason for these issues is the increased penetration capabilities of renewable energy sources. An imbalanced load with significant power output has a substantial impact on the frequency and voltage characteristics of electrical networks. Various load frequency control (LFC) technologies are widely used to address these issues. Existing LFC approaches in the literature are inadequate in addressing system uncertainty, parameter fluctuation, structural changes, and disturbance rejection. As a result, the purpose of this work is to suggest a better LFC approach that makes use of a combination of a one plus tilt fractional filtered derivative (1+TDF^λ) cascaded controller and a fractional order proportional–integral–derivative (PI^λD^μ) controller, which is referred to as the recommended 1+TDF^λ/PI^λD^μ controller. Drawing inspiration from the dynamics of religious societies, including the roles of followers, missionaries, and leaders, and the organization into religious and political schools, this paper proposes a new application of the efficient divine religions algorithm (DRA) to improve the design of the 1+TDF^λ/PI^λD^μ controller. A triple-area test system is constructed to analyze a realistic power system, taking into account certain physical restrictions such as nonlinearities as well as the impact of PV and wind energy integration. The effectiveness of the presented 1+TDF^λ/PI^λD^μ controller is evaluated by comparing their frequency responses to those of other current controllers like PID, FOPID, 2DOF-PID, and 2DOF-TID^μ. The integral time absolute error (ITAE) criterion was employed as the objective function in the optimization process. Comparative simulation studies were conducted using the proposed controller, which was fine-tuned by three recent metaheuristic algorithms: the divine religions algorithm (DRA), the artificial rabbits optimizer (ARO), and the wild horse optimizer (WHO). Among these, the DRA demonstrated superior performance, yielding an ITAE value nearly twice as optimal as those obtained by the ARO and WHO. Notably, the implementation of the advanced 1+TDF^λ/PI^λD^μ controller, optimized via the DRA, significantly minimized the objective function to $0.4704\times {10}^{-4}$. This reflects an approximate enhancement of $99.5\%$ over conventional PID, FOPID, and 2DOF-TID^μ controllers, and a $99\%$ improvement relative to the 2DOF-PID controller. The suggested case study takes into account performance comparisons, system modifications, parameter uncertainties, and variations in load/generation profiles. Through the combination of the suggested 1+TDF^λ/PI^λD^μ controller and DRA optimization capabilities, outcomes demonstrated that frequency stability has been significantly improved. Full article

This study investigates the performance of thermoacoustic engines by examining the influence of stack position, resonator length, and working fluid on energy conversion efficiency. Numerical simulations reveal that placing the stack at an intermediate location (e.g., 60 mm in a 350 mm resonator) maximises efficiency by promoting stable, single-mode harmonic oscillations and minimising boundary layer interference. Deviations from this optimal position (e.g., 30 mm or 90 mm) induce secondary harmonics, reducing efficiency. Doubling the resonator length while maintaining proportional stack scaling preserves performance, indicating aspect ratio is not a limiting factor. Simulations with helium, as opposed to air, yield a tripled resonance frequency (∼$700 \mathrm{H}\mathrm{z} \mathrm{v}\mathrm{s}. 245 \mathrm{H}\mathrm{z}$) and significantly higher efficiency (∼$0.38 \mathrm{vs}. \sim 0.13$), due to helium’s superior thermal and acoustic properties. These results provide quantitative guidelines for optimising thermoacoustic engine design for sustainable energy applications. Full article

Tower crane structural failures remain a major safety concern on construction sites. To improve accident prevention, this study proposes an intelligent framework that combines an improved Transformer model with a Directional Interest Score (DIS) Apriori algorithm and complex-network analysis. A corpus of 535 tower crane accident reports (2002–2024) was compiled and annotated with causal and accident entities according to system–safety theory. Segment embeddings were introduced to the Transformer to reinforce boundary detection, enabling accurate extraction of causative factors and relation triples. The DIS-Apriori algorithm was then used to mine both positive and negative association rules while aggressively pruning irrelevant item sets. Eventually, causative factors were mapped into a weighted, directed complex network where edge weights reflect the absolute frequency difference between positive and negative rules, and edge directions correspond to their signs. Experiments show that the Transformer achieves higher precision and recall than baseline models, and DIS-Apriori substantially reduces unnecessary item-set complexity while preserving critical rules. Network analysis revealed five critical causal links and a closed-loop causal link that warrant priority intervention. The proposed method delivers a data-driven, explainable tool for pinpointing key risk sources and designing targeted mitigation strategies, offering practical value for intelligent safety management of tower cranes. Full article

Multilevel active bridge converters are potential candidates for many modern high-power DC applications due to their ability to integrate multiple sources while minimizing weight and volume. Therefore, this paper deals with an analytical, simulation-based, and experimentally verified investigation of their circulating current behavior, power factor performance, and power loss characteristics. A high-frequency link analysis framework is developed to characterize voltage, current, and power transfer waveforms, providing insight into reactive power generation and its impact on overall efficiency. By introducing a modulation-based control approach, the proposed converters significantly reduce circulating currents and enhance the power factor, particularly under varying phase-shift conditions. Compared to quadruple active bridge topologies, the discussed multilevel architectures offer reduced transformer complexity and improved power quality, making them suitable for demanding applications such as electric vehicles and aerospace systems. Full article

To resolve the conflict between global structure modeling and local detail preservation in image super-resolution, we propose SwinT-SRGAN, a novel framework integrating Swin Transformer with GAN. Key innovations include: (1) A dual-path generator where Transformer captures long-range dependencies via window attention while CNN extracts high-frequency textures; (2) An end-to-end Detail Recovery Block (DRB) suppressing artifacts through dual-path attention; (3) A triple-branch discriminator enabling hierarchical adversarial supervision; (4) A dynamic loss scheduler adaptively balancing six loss components (pixel/perceptual/high-frequency constraints). Experiments on CelebA-HQ and Flickr2K demonstrate: (1) Very good performance (max gains: 0.71 dB PSNR, 0.83% SSIM, 4.67 LPIPS reduction vs. Swin-IR); (2) Ablation studies validate critical roles of DRB. This work offers a robust solution for high-frequency-sensitive applications. Full article

Objective: Anterior cruciate ligament (ACL) graft failure or contralateral ACL injury after returning to sport (RTS) post-ACL reconstruction remains problematic. Re-injury prevention programs that “bridge” standard physical therapy and release to unrestricted sports participation can help. This observational study evaluated the characteristics of athletes who sustained an ipsilateral ACL graft or contralateral ACL injury after RTS bridge program participation. Materials and Methods: Comparisons were made between RTS bridge program participants who either had or had not sustained an ipsilateral ACL graft or contralateral ACL injury following RTS. Post-program objective physical function tests, pre- and post-program Knee Outcome Survey Sports Activity Scale (KOS-SAS), global sports activities knee function scores, sports activities knee function rating improvements, and post-program sport performance ability perceptions were evaluated. Results: A total of 204 athletes (19.7 ± 6 years of age, 108 males) completed the RTS bridge program and were released back to sports at 8.5 ± 2.3 months post-surgery. Groups had similar pre-morbid performance level restoration perceptions. Taller and heavier male athletes displayed greater single leg triple hop for distance magnitude, and quicker single leg timed hop, single leg timed crossover hop, and NFL 5-10-5 and NFL “L” times. Bilateral physical function test symmetry results did not differ between groups. By 7.8 ± 4 years post-surgery, 17 subjects sustained either ipsilateral ACL graft injury (n = 6) or contralateral ACL injury (n = 11), with a similar frequency between males and females (p = 0.30). Athletes who sustained an ipsilateral ACL graft or contralateral ACL injury were younger, and more often scored ≥ 25th percentile for post-program global sports activities knee function and KOS-SAS scores; more frequently had two-level overall sports activities knee function rating improvements; and tended to sustain this new knee injury during the initial RTS season. Conclusions: Factors other than physical function or performance capability may possess a strong influence on ipsilateral ACL graft or contralateral ACL injury following RTS bridge program participation. Full article

China’s media governance policies play a crucial role in shaping media ecology and promoting the modernization of national governance capacity. This study employed the Latent Dirichlet Allocation (LDA) model and co-occurrence network analysis to systematically analyze the thematic content of national-level media governance policies issued in China between 1996 and 2024, and to examine the evolution of policy themes from a triple logical synergy perspective. In consideration of the socio-economic context and governance issues, this study has categorized the evolution of media governance policies into four distinct phases. This study used the LDA model to extract high-frequency words and built a co-occurrence network to explore the structural relationship among these words, with a synergy framework to analyze the thematic evolution across periods. The findings indicate that China’s media governance policies over the past three decades have been the result of stage-by-stage adjustments under the synergistic influences of technological drivers, social demands, and governance philosophies. Media governance constitutes a pivotal component in the modernization of China’s national governance capacity. A comprehensive analysis of the evolution of policy themes reveals the internal pattern of media governance in China. Full article

In order to solve the problems of modulation signals in low signal-to-noise ratio (SNR), such as poor feature extraction ability, strong dependence on single modal data, and insufficient recognition accuracy, this paper proposes a multi-dimensional feature MFCA-transformer recognition network that integrates phase, frequency and power information. The network uses Triple Dynamic Feature Fusion (TDFF) to fuse constellation, time-frequency, and power spectrum features through the adaptive dynamic mechanism to improve the quality of feature fusion. A Channel Prior Convolutional Attention (CPCA) module is introduced to solve the problem of insufficient information interaction between different channels in multi-dimensional feature recognition tasks, promote information transmission between various feature channels, and enhance the recognition ability of the model for complex features. The label smoothing technique is added to the loss function to reduce the overfitting of the model to the specific label and improve the generalization ability of the model by adjusting the distribution of the real label. Experiments show that the recognition accuracy of the proposed method is significantly improved on the public datasets, at high signal-to-noise ratios, the recognition accuracy can reach 93.2%, which is 3% to 14% higher than those of the existing deep learning recognition methods. Full article

Rydberg atoms play a crucial role in testing atomic structure theory, quantum computing and simulation. Measurements of transition frequencies from the $2^{1,3}S$ states to Rydberg ${}^{1,3}P$ states have reached a precision of several kHz, which poses significant challenges for theoretical calculations, since the accuracy of variational energy calculations decreases rapidly with increasing principal quantum number n. Recently the complex “triple” Hylleraas basis was employed to attain the ionization energy of helium $24{}^{1}P$ state with high accuracy. Different from it, we extended the correlated B-spline basis functions (C-BSBFs) to calculate the Rydberg states of helium. The nonrelativistic energies of $1snp$${}^{1,3}P$ states up to $n=27$ achieve at least 14 significant digits using a unified basis set, thereby greatly reducing the complexity of the optimization process. Results of geometric structure parameters and cusp conditions were presented as well. Both the global operator and direct calculation methods are employed and cross-checked for contact potentials. This C-BSBF method not only obtains high-accuracy energies across all studied levels but also confirms the effectiveness of the C-BSBFs in depicting long-range and short-range correlation effects, laying a solid foundation for future high-accuracy Rydberg-state calculations with relativistic and QED corrections included in helium atom and low-Z helium-like ions. Full article

The displacement of bridge towers is relatively large under strong wind action. Changes in tower displacement can reflect the usage status of the bridge towers. Therefore, it is necessary to conduct performance warning research on tower displacement under strong wind action. In this paper, the triple standard deviation method, multiple linear regression method, and interpolation method are used to preprocess monitoring data with skipped points and missing anomalies. An improved multi-rate data fusion method, validated using simulated datasets, was applied to correct monitoring data at bridge tower tops. The fused data were used to feed predictive models and generate structural performance alerts. Spectral analysis confirmed that the fused displacement measurements achieve high precision by effectively merging the low-frequency GPS signal with the high-frequency accelerometer signal. Structural integrity monitoring of wind-loaded bridge towers used modeling residuals as alert triggers. The efficacy of this proactive monitoring strategy has been quantitatively validated through statistical evaluation of alarm accuracy rates. Full article

This article investigates how to exploit the high-frequency mmWave for 5G-advanced and beyond, which requires new filters for the wide bandpass and its multi-sub-band. Based on the substrate-integrated waveguide (SIW), spoof surface plasmon polariton (SSPP), and metastructures, like complementary split-ring resonators (CSRRs), the development of a wide bandpass filter and a multi-sub-band filter is proposed, along with an experimental realization to verify the model. The upper and lower cutoff frequencies of the wide bandpass are controlled through an SIW-SSPP structure, whereas the corresponding wide bandpass and its multi-sub-band filters are designed through incorporating new metastructures. The frequency range of 24.25–29.5 GHz, which covers the n257, n258, and n261 bands for 5G applications, was selected for verification. The basic SIW-SSPP wide bandpass structure of 24.25–29.5 GHz was designed first. Then, by incorporating an Archimedean spiral configuration, the insertion loss within the passband was reduced from 1 dB to 0.5 dB, while the insertion loss in the high-frequency stopband was enhanced from 40 dB to 70 dB. Finally, CSRRs were integrated to effectively suppress undesired frequency components within the bandpass, thereby achieving multi-sub-band filters with low insertion losses with a triple-sub-band filter of 0.5 dB, 0.7 dB, and 0.8 dB in turn. The experimental results showed strong agreement with the design scheme, thereby confirming the rationality of the design. Full article