Search Results (360)

Reverse arch beam string-inclined column structures have been applied in large-scale event venues due to their unique load-bearing characteristics. However, ensuring their resistance to progressive collapse remains a critical challenge. To investigate the structural robustness of reverse arch beam string-inclined column structure in practical engineering applications, a simplified finite element model is developed herein using ANSYS APDL. The natural frequencies of the actual engineering structure are measured through the hammering method to validate the accuracy of the simulation model. Based on the component removal method, different structural components are removed and finite element analysis is carried out. The dynamic response of the overall structure and the importance coefficients of individual components after removal are examined. The results demonstrate good agreement between the natural frequencies measured by the impact hammer test and those predicted by the finite element simulations, with the difference being only 1.67%. It is found that upper beam failure is fatal to this structure; the outer inclined columns significantly affect the robustness of the structure, while the failure of a single strut has a negligible impact. According to the component division, the importance of the overall robustness of the structure is in the following order: upper beam > column end > column base > strut. The maximum stress is mostly located in beam 7, beam 8, beam 28, and beam 107, which needs to be focused on. Full article

This research is based on the acoustic package design of new energy vehicles, investigating the application of the hybrid Finite Element–Statistical Energy Analysis (FE-SEA) model in predicting the high-frequency dynamic response of automotive structures, with a focus on the modeling and correction methods for hybrid point connections. New energy vehicles face unique acoustic challenges due to the special nature of their power systems and operating conditions, such as high-frequency noise from electric motors and electronic devices, wind noise, and road noise at low speeds, which directly affect the vehicle’s ride comfort. Therefore, optimizing the acoustic package design of new energy vehicles to reduce in-cabin noise and improve acoustic quality is an important issue in automotive engineering. In this context, this study proposes an improved point connection correction factor by optimizing the division range of the decision circle. The factor corrects the dynamic stiffness of point connections based on wave characteristics, aiming to improve the analysis accuracy of the hybrid FE-SEA model and enhance its ability to model boundary effects. Simulation results show that the proposed method can effectively improve the model’s analysis accuracy, reduce the degrees of freedom in analysis, and increase efficiency, providing important theoretical support and reference for the acoustic package design and NVH performance optimization of new energy vehicles. Full article

This paper presents the design and experimental evaluation of a compact microstrip patch antenna and a 4 × 4 phased antenna array system tailored for Wi-Fi 6E applications, U-NII-5 band. A single inset-fed microstrip patch antenna was first optimized through full-wave simulations, achieving a resonant frequency of 5.96 GHz with a measured return loss of −17.5 dB and stable broadside radiation. Building on this element, a corporate-fed 4 × 4 array was implemented on an FR4 substrate, incorporating stepped-impedance transmission lines and λ/4 transformers to ensure equal power division and impedance matching across all ports. A 4-bit digital phase shifter, controlled by an ATmega328p microcontroller, was integrated to enable electronic beam steering. Simulated results demonstrated accurate beam control within ±28°, with directional gains above 13 dBi and minimal degradation compared to the broadside case. Over-the-air measurements validated these findings, showing main lobe steering at 0°, ±15°, +33° and −30° with peak gains between 7.8 and 11.5 dBi. The proposed design demonstrates a cost-effective and practical solution for Wi-Fi 6E phased array antennas, offering enhanced beamforming, improved spatial coverage, and reliable performance in next-generation wireless networks. Full article

This paper presents dual-layer frequency selective surfaces (FSSs) with frequency division control function through an integrated tunable transmission window at a lower frequency and an absorption performance at a higher frequency. The bottom frequency selective surface (FSS) layer, configured as a bandpass structure, incorporates a gradient gap square-ring element loaded with varactor diodes. This configuration enables dynamic tuning of the L-band transmission window from 1.26 GHz to 1.9 GHz via varactor capacitance modulation. Simultaneously, the top FSS layer utilizes a square-ring-cross-slot topology. Leveraging the strong reflection characteristic of the bottom FSS at higher frequencies in conjunction with dielectric loss mechanisms, the structure achieves absorption performance within the 5.56 GHz to 5.72 GHz band. Measurement results indicate insertion loss at operational frequencies within the transmission window remains below 1.41 dB, while the absorption peak reaches approximately −30 dB. Close agreement between simulated and measured results validates the proposed design. Full article

We propose a dual-groove few-mode fiber surface plasmon resonance sensor that exploits the LP₁₁ mode for enhanced plasmonic sensing. The device incorporates two physically separated grooves with distinct metallic coatings, enabling dual-channel operation via wavelength-division multiplexing. Finite element method simulations show that the optimized design achieves a maximum sensitivity of 14,800 nm/RIU within the RI range of 1.33–1.40. The introduction of a TiO₂–Au bilayer enhances mode coupling and ensures complete spectral separation, thereby improving stability and reducing environmental interference. Biosensing simulations at 37 °C further confirm the practicality of the proposed architecture. Channel 1, filled with ethanol as a temperature-sensitive medium, provides temperature monitoring, while Channel 2 successfully distinguishes between normal and tumor cells, reaching a sensitivity of up to 9428.57 nm/RIU for Jurkat cells. Overall, the TiO₂-enhanced dual-channel FMF-SPR sensor combines ultra-high sensitivity, spectral independence, and biosensing capability, demonstrating strong potential for next-generation fiber-optic sensing and biomedical applications. Full article

In this paper, we design a new type of terahertz orbital angular momentum (OAM) optical fiber with excellent transmission characteristics over a wide frequency range. Within the 0.8–1.8 THz frequency band, it shows stable support for transmission of the fifth-order OAM mode. Its dispersion control effect is excellent; it maintains the confinement loss of most modes at the extremely low level of 10⁻¹⁰ dB/m; its maximum dispersion is only 5.57 ps/THz/cm; and its effective mode field area is greater than 1.11 × 10⁻⁷ m². These characteristics jointly endow this optical fiber with broad application prospects and significant research value in the field of terahertz communication. With the continuous advancement of technology in this field, this optical fiber is expected to become a key component when building efficient, reliable, and large-capacity communication systems. Full article

The trade-offs and synergies among ecosystem services can provide clues for understanding the mechanisms of regional ecological evolution. Previous studies have mainly concentrated on administrative divisions to characterize ecosystem services trade-offs and synergies within specific regions. However, ambiguity persists regarding the spatial diversity and scale dependency of regional ecosystem services, along with the degree to which human activity and climatic variation influence the relationships of multiscale ecosystem services. This study focuses on the Yangtze River Delta Urban Agglomeration in China. Based on grid, county-level, and city-level scales, it analyzes five ecosystem services, namely habitat quality, carbon storage, food production, soil conservation, and water yield, from 2000 to 2020. By using correlation analysis and spatial autocorrelation methods, this study explores the intensity of the trade-offs and synergies among ecosystem services and their spatial patterns. Then, combined with the Optimal Parameters-based Geographical Detector, it identifies the dominant driving factors, quantifies their degree of contribution, and reveals the multiscale differentiation of ecosystem service relationships and their causes. The results show that the five ecosystem services all exhibit significant spatiotemporal heterogeneity. At the grid scale, there is a trade-off relationship between food production and the other four services, while a strong synergistic effect exists among the remaining four services. At the county scale, the synergistic association between habitat quality and carbon storage is the most significant, with the highest contributions from the average annual precipitation and average annual temperature (q-values 0.893 and 0.782, respectively). At the prefecture-level city scale, the intensity of the ecosystem services trade-offs and synergies shows an increasing trend, and the impact of interactions between socio-ecological elements is significantly higher than that at the grid and county scales. This research provides an evidence-based foundation for decision makers to devise suitable strategies that support the coordinated advancement of ecology and the economy across various spatial scales. It is crucial for promoting precise ecosystem regulation and the sustainability of the Yangtze River Delta Urban Agglomeration in China. Full article

This work establishes the first derivation of geometry-dependent Kirchhoff’s laws via conformal symmetry, enabling new types of self-sustaining circuits unattainable in classical lumped-element theory. Building on Bessel-Hagen’s extension of Noether’s theorem to Maxwell’s equations, we develop a conformal circuit formalism that fundamentally extends traditional circuit theory through two key innovations: (1) Geometry-dependent weighting factors ($w_i\propto a_i^{-1}$) in Kirchhoff’s laws derived from scaling symmetry; (2) A dilaton-like field ($\delta$) mediating energy exchange between circuits and conformal backgrounds. Unlike prior symmetry applications in electromagnetism, our approach directly maps the 15-parameter conformal group to component-level circuit transformations, predicting experimentally verifiable phenomena: (i) $10.2\%$ deviations from classical current division in RF splitters; (ii) $4.2\%$ resonant frequency shifts with $2.67\times$ Q-factor enhancement; (iii) Power-law scaling ($J_z\propto a^{-2}$) in cylindrical conductors. This theoretical framework proposes how conformal symmetry could enable novel circuit behaviors, including potential self-sustaining oscillations, subject to experimental validation. Full article

Background/Objectives: Nutrigenomics explores how dietary components influence genome function, especially via epigenetic mechanisms like DNA methylation. A key challenge is identifying healthy food-derived molecules capable of counteracting epigenetic damage from harmful dietary elements. Pistachio nuts (Pistacia vera L.), particularly the Bronte variety from Sicily, are rich in antioxidant polyphenols. In this study we used a methylomic approach to assess the nutrigenomic potential of a hydrophilic extract from Bronte pistachio (BPHE) in a model of human intestinal epithelium, as well as its capacity to modulate arsenic (As)-induced epigenotoxicity. Methods: BPHE was obtained via ethanol/water Soxhlet extraction. CaCo-2 cells were treated with BPHE, alone and after exposure to sodium arsenite. The methylation pattern of the genomic DNA was assessed by methylation-sensitive arbitrarily primed PCR and the methylomic signature was defined by Next-generation bisulfite sequencing. Results: BPHE alone did not alter DNA methylation pattern but, at the highest dose, modulated the changes induced by As. The identification of differentially methylated gene promoters in cell treatment vs. untreated controls revealed that BPHE and As primarily induced hyper-methylation, with a synergistic effect when combined. In particular, all the treatments increased methylation levels of gene categories such as pseudogenes, key genes of specific pathways, genes for zinc-finger proteins, homeobox proteins, kinases, antisense RNA, and miRNA. Notably, in co-treatment with As, BPHE promoted hypo-methylation of genes involved in tumor suppression, detoxification, mitochondrial function, and cell division. Conclusions: These findings suggest that Bronte pistachio polyphenols may epigenetically steer gene expression toward a protective profile, reducing risks of genomic instability and disease. This supports their potential as nutraceuticals to counter harmful epigenetic effects of toxic food components like arsenic. Full article

The term chromosomal imprinting was introduced to denote the parent-of-origin-dependent behavior of chromosomes in the fungus gnat originally named Sciara coprophila (current taxonomic name is Bradysia coprophila). Such behavior is observed in Sciara coprophila embryos, where paternal X chromosomes (X_p) are specifically eliminated during the 7th–8th cleavage divisions. Elimination is regulated by a controlling element (CE) that has been mapped to heterochromomere II (H2) within the sub-telomeric short arm of polytene X chromosomes. Here, using a combination of a new Sciara genome assembly, along with ChIP-Seq and MeDIP analyses, we show that a 1.2 Mb region within the CE locus has a repressive epigenetic signature that is characterised by enrichments of H3K9me3, H4K20me3 and 5′-methyl cytosine (5meC). These data provide evidence for a model where the H3K9me3/HP1/H4K20me3 pathway operates to assemble a heterochromatin-like complex at the CE that renders it silent on X_p chromosomes that are not eliminated. In this regard, our findings support the idea that the H3K9me3/HP1/H4K20me3 pathway represents the most evolutionarily conserved mechanism linked to chromosomal imprinting in animals. Full article

Background: Selenium (Se) is a trace mineral element with important roles in enhancing athletic performance and athlete recovery. Objectives: This study aimed to observe the differences in plasma, urinary, erythrocyte, and platelet Se concentrations between sexes and analyze the variations in Se concentrations during the soccer season. The main hypothesis was that significant differences in Se levels would be observed between male and female athletes and that these differences would fluctuate throughout the season due to varying training loads and nutritional factors. Methods: Twenty-two male (20 ± 2 years; 1.76 ± 0.06 m; 14.73 ± 3.13 years’ experience; fifth Spanish division) and twenty-four female soccer players (23 ± 4 years; 1.65 ± 0.06 m; 14.51 ± 4.94 years’ experience; second Spanish division) participated. Three assessments were conducted during the season. Evaluations included anthropometry, body composition, fitness (cardiorespiratory and vertical jump), and nutritional intake. Venous samples of blood and urine were obtained. The concentrations of Se in the plasma, urine, erythrocytes, and platelets were analyzed through inductively coupled plasma mass spectrometry. Results: No differences in Se intake were observed. The Se concentrations in the plasma, urine, and platelets were found to be higher in males, while females showed elevated levels in their erythrocytes (p < 0.05). Throughout the season, plasma and platelet Se concentrations exhibited a progressive increase (p < 0.05). Conclusions: Assessing Se status during the season is essential for evaluating nutritional supplementation to maintain performance given Se’s vital role in the immune and antioxidant systems. Full article

Gas turbines in land-based microgrids and shipboard-isolated power grids frequently face operational challenges, such as the startup and shutdown of high-power equipment and sudden load fluctuations, which significantly impact their performance. To examine the dynamic behavior of gas turbines under transitional operating conditions, a three-dimensional computational fluid dynamic simulation is employed to create a model of the gas turbine rotor, incorporating thermal inertia, which is then analyzed in conjunction with three-dimensional finite element methods. The governing equations of the flow field are discretized, providing results for the flow and temperature fields throughout the entire flow path. A hybrid approach, combining temperature differences and heat flux density, is applied to set the thermal boundary conditions for the walls, with the turbine’s operational state determined based on the direction of heat transfer. Additionally, mesh division techniques and turbulence models are selected based on the geometric dimensions and operating conditions of the compressor and turbine. The simulation results reveal that thermal inertia induces a shift in the dynamic characteristics of the rotor components. Under the same heat transfer conditions, variations in rotational speed have a minimal impact on the shift in the characteristic curve. The working fluid temperature inside the compressor components is lower, with a smaller temperature difference from the wall, resulting in less intense heat transfer compared to the turbine components. Overall, heat transfer accounts for only about 0.1% of the total enthalpy at the inlet. When heat exchange occurs between the working fluid and the walls, around 6–15% of the exchanged heat is converted into changes in technical work, with this percentage increasing as the temperature difference rises. Full article

This paper introduces a novel recursive algorithm for inverting matrix polynomials, developed as a generalized extension of the classical Leverrier–Faddeev scheme. The approach is motivated by the need for scalable and efficient inversion techniques in applications such as system analysis, control, and FEM-based structural modeling, where matrix polynomials naturally arise. The proposed algorithm is fully numerical, recursive, and division free, making it suitable for large-scale computation. Validation is performed through a finite element simulation of the transverse vibration of a fighter aircraft wing. Results confirm the method’s accuracy, robustness, and computational efficiency in computing characteristic polynomials and adjugate-related forms, supporting its potential for broader application in control, structural analysis, and future extensions to structured or nonlinear matrix systems. Full article

The TRM (TONNEAU1 Recruiting Motif) gene family plays a crucial role in multiple biological processes, including microtubule organization, cell division regulation, fruit morphogenesis, stress adaptation, and growth and development. To delve deeper into the potential functions of BnaTRMs in Brassica napus, this study employed bioinformatics methods to systematically identify and analyze the TRM family genes in Brassica napus (Westar). Using the model plant Arabidopsis thaliana as a reference and based on six conserved motifs, 100 TRM members were first identified in Brassica napus. These genes are widely distributed across 19 chromosomes, and most exhibit nuclear localization characteristics. Through gene collinearity analysis among Brassica napus, Arabidopsis thaliana, Glycine max, Oryza sativa, and Zea mays, we speculate that Brassica napus and Glycine max may share a similar evolutionary history. Analysis of cis-acting elements in the 2000 bp upstream region of TRM gene promoters revealed numerous elements related to abiotic stress response and hormone regulation. Furthermore, qRT-PCR data supported these findings, indicating that multiple TRM genes actively participate in the growth and development process and abiotic stress tolerance of Brassica napus. In summary, BnaTRMs exhibit significant functions in stress adaptation, growth, and development. This study not only enhances our understanding of the functions of the TRM gene family but also provides new perspectives and strategies for further exploring their regulatory mechanisms and potential applications. Full article

The traditional finite element method deals with the temperature field around the cooling tube due to the computational efficiency problems caused by grid division and the uncertainty of the convective heat transfer coefficient, resulting in inaccurate calculation results around the cooling tube. We conducted experiments to study the thermal stress and temperature gradient caused by various factors such as different materials of cooling pipes, pipe diameters, cooling water temperatures, and flow rates. The results showed that aluminum alloy pipes had the highest cooling efficiency but also produced a large temperature gradient. Pipe diameter had the most significant impact on cooling efficiency. Additionally, it is recommended that the cooling water flow velocity is not less than 0.6 m/s to achieve the best efficiency for the cooling pipe of any pipe diameter. The influence range of the cooling pipe on concrete could vary with pipe material, flow rate, and ambient factors. Our experimental results were compared with other heat transfer formulas (the Dittus–Boelter formula and the Yang Joo-Kyoung formula). According to the measured results, the formula is modified). The modified formula can estimate the heat transfer coefficient more accurately according to the flow rate and pipeline characteristics. Finally, the applicability of the formula is further verified by comparing the concrete on the bottom plate of a dam. The proposed heat transfer prediction model can estimate the heat transfer coefficient according to the flow rate and pipeline characteristics, The accuracy of the convection coefficient under different working conditions is improved by 10–25%. It is convenient to predict concrete temperature in practical engineering. Full article