Brick heritage buildings in the hot and humid regions of southern China are exposed to coupled high-temperature and high-humidity conditions. Moisture retention within brick walls and cyclic crystallization of soluble salts jointly drive material deterioration and structural damage, posing persistent threats to the authenticity, integrity, and long-term preservation of these heritage buildings. The Site of the First National Congress of CPC is a Major Historical and Cultural Site Protected at the National Level. Focusing on its brick facades, this study integrates microwave-based nondestructive testing, microscopic observation, X-ray diffraction (XRD), and X-ray fluorescence (XRF) spectroscopy to systematically investigate the spatiotemporal distribution of internal moisture content and the morphological and compositional characteristics of surface salt damage. The results show that, during the monitoring period from February 2025 to January 2026, moisture content in both the south and east facades exhibited pronounced seasonal fluctuations, with peak values occurring in summer, particularly from June to August. Moisture content at the depth of 5 cm responded rapidly to short-term environmental variations, and the moisture distribution showed obvious spatial heterogeneity. However, moisture content at the depth of 10 cm exhibited a delayed response and remained generally at higher values. Salt-damage products were composed primarily of quartz, calcium carbonate, and sulfates. The brick material was accompanied by deterioration phenomena such as flaking and granular disintegration. It is essential for scientific and refined conservation of heritage buildings to develop targeted measures based on the deterioration characteristics and mechanisms at different facade areas.

This study aimed to investigate the corrosion of glaze layers on ancient ceramics recovered from waters under the influence of marine biofouling. Taking the ancient ceramic samples recovered from the Yellow Sea waters of Rongcheng City, Shandong Province as the research objects, the study analyzed the characteristics of corrosion on the ceramic glaze layers due to the biological sedimentation and adhesion of bryozoans, hydroides, oysters, etc. It was employed m-X-ray fluorescence spectrometer (m-XRF), scanning electron microscope (SEM)-energy dispersive spectroscope (EDS), X-ray diffraction (XRD), X-ray photoelectron spectroscope (XPS), pyrolysis-gas chromatography-mass spectrometry (PY-GC/MS), and microbial sequencing. The results showed that bryozoans densely colonized the ceramic surfaces in a punctate pattern. At attachment sites, organic proteinaceous cements were present, appearing black in color, with the corrosive material primarily composed of Fe/Mn oxides. Oysters adhered preferentially to roughened ceramic areas and were associated with abundant spore-like carbonaceous particles. Hydroides exhibited a striated external morphology and internal scale-like structures at the interface, with the attachment zones being rich in diatoms, which contributed to the formation of black corrosion products composed primarily of FeO(OH). Microbial communities such as Delftia and Pseudomonas were detected on the ceramic surfaces. Furthermore, the corrosion areas contained alanine and glycine derived from proteinaceous cements, as well as methyl stearate produced through microbial degradation. These findings further confirmed the corrosive effects of marine microorganisms, as well as their metabolism and degradation, on biological sedimentation on ceramic surfaces. The results provided important scientific evidences for understanding marine-biofouling-induced interfacial corrosion of recovered ceramics from waters.

Hydrogen energy with advantages such as high calorific value and zero-carbon emission can provide high-quality frequency regulation resources for microgrids. However, safety constraints such as response frequency and ramp rate of power-to-hydrogen (P2H) devices pose challenges to load frequency control (LFC) strategy design in microgrids. This paper proposes an adaptive event-triggered LFC design scheme for microgrids. Firstly, a bilateral adaptive event-triggered LFC communication scheme is designed for microgrids. The operating power points of frequency regulation devices including P2H devices can be adjusted only when the control performance is degenerated below the preset level, which effectively reduces the action frequency of P2H devices. Secondly, considering the ramp constraints of P2H devices, the event-triggered LFC system in microgrids is modeled as a saturated nonlinear model. Finally, the design criteria for event-triggering and controller parameters are determined by constructing a Lyapunov function. Simulation results show that P2H device participation can decrease the frequency deviation amplitude of the microgrid by 6.24% and shorten the settling time by 1.55%, thereby effectively enhancing the frequency stability of the microgrid.

The locations and severity of interturn short circuits in windings can be determined from the characteristic electromagnetic field parameters associated with such faults, which is crucial for their timely detection. This study establishes an electromagnetic coupling model for interturn short circuits in transformer windings and verifies its accuracy and effectiveness by comparing simulated and experimental winding currents under interturn short circuit conditions. Subsequently, the variations in winding currents, core flux, and winding flux when interturn faults occur in high-voltage windings are investigated. The effects of the number of short-circuited turns and the fault location on these parameters are further analyzed in depth. The findings of this study provide a theoretical basis for diagnosing interturn short circuits at different locations and of different severity in three-phase transformers.

Conductor on round core (CORC) cables, made from high-temperature superconducting coated conductors, are considered one of the most promising cable architectures for power applications due to their superiority in current capacity and flexibility. The main factors hindering the large-scale application and development of CORC cables are high manufacturing costs and cooling costs, the latter of which is attributed to AC loss. In actual electromagnetic environments, the rapid switching transient process of power equipment and the nonlinear characteristics of passive components (capacitors and inductors) can cause harmonic distortion in power grids, resulting in superconducting tapes carrying non-sinusoidal current. Different transport current waveforms and cable topologies influence AC loss. However, the modulation effect of current waveforms on the transport AC loss of CORC cables is not yet clear. Based on the H equation, this paper comprehensively explores the effect of current waveforms and their frequencies on the AC loss of high-temperature superconducting CORC cables with different layers, providing valuable references for the design of low-loss waveforms, high-frequency applications, and multi-layer structure regulation of CORC cables.

With the development of intelligent substations, intelligent operation and maintenance (O&M) within the substation has become a crucial means of improving efficiency and reducing risks. Intelligent O&M requires comprehensive collection of substation operational data and data-driven decision-making supported by intelligent algorithms to achieve safe and efficient O&M. Most functions within the substation, such as target localization, recognition, and tracking, rely on visual terminals, underscoring the importance of the camera network deployment scheme. To address the issue, this study proposes a camera deployment optimization scheme based on discrete-variable three-dimensional (3D) viewshed analysis, considering the practical conditions of intelligent substation O&M. A mathematical model is constructed under various possible constraints, including camera types and cost budgets, by dividing the 3D space into viewsheds with different levels of importance. A numerical optimization scheme is then proposed to determine the placement and types of cameras required for intelligent substation O&M in compliance. It not only enables necessary point-to-point parameter monitoring but also meets the requirements for collaborative operation among camera networks. The proposed scheme has broad methodological applicability and can be readily extended to substations in different regions and of other types.

Optical polarization features can enhance the image information of camouflaged targets under low illumination; however, the spatial polarization characteristics of objects are complex and change under different detection conditions. To investigate the distribution law of the spatial polarization characteristics of scattered mine targets, an optical polarization observation system based on a multi-angle measuring frame was designed and constructed, and polarization imaging experiments with multiple incidence and observation angles were conducted on several typical mines and common ground backgrounds. The experimental results show that the polarization of all types of measured targets is affected by different observation directions to a certain extent. In particular, the polarization of landmine targets varies greatly with the observation direction, and the polarization of sand is less affected by the observation direction. Near the specular reflection direction of the incident light, the polarization difference between landmine targets and the ground background reaches the maximum, and appropriately increasing the incident zenith angle can help improve the discrimination between the dispersal of landmine targets and the background environment. Therefore, the ability to distinguish between a dispersed mine target and the ground background was improved by appropriately increasing the incident zenith angle.

To solve the low accuracy of model translation words owing to the lack of parallel corpora and variable meanings in the current ancient Chinese machine translation model, a Transformer-based pre-trained feature center algorithm model is proposed. This method first trains the language model to extract pretrained feature centers to improve generalization ability when parallel corpora are insufficient. Second, the Transformer generates queries in the feature center space and determines the generation based on the distance between the queries in the feature center to improve the model’s understanding of polysemy. The experimental results indicate that the generation accuracy of the proposed method is generally higher than that of the benchmark model. In the XiHan Datasets, BLEU 1~4 scores were 6.1, 4.9, 3.7, and 2.8 higher than those of the Transformers. In the WuDaiShiGuo Datasets, the BLEU 1~4 scores were 4.2, 4.2, 3.3, and 2.6 higher than those of the Transformers. In the Tang Datasets, the BLEU 1~4 scores were the best. Simultaneously, compared with the Transformer, the parameter count of the proposed method decreased by 5.73 M, demonstrating its advantages.

By investigating the invulnerability of semi-directed wireless sensor networks, this paper provides a theoretical basis for formulating effective invulnerability strategies. The paper uses the grey system theory to characterize the widespread incomplete information in the network. By applying the generating function method, it successfully derives the critical removal ratio and the size of the giant connected component of semi-directed random networks with arbitrary degree distribution. The topologies of semi-directed wireless sensor networks are described by simulation, and the invulnerability analysis of semi-directed wireless sensor networks is carried out, with the Barabási-Albert (BA) scale-free network taken as a typical case for simulation analysis. The results indicate that the intentional dynamic attack has obvious advantages over the random attack and the intentional static attack in attack efficiency. This conclusion provides an important reference for formulating strategies to improve the invulnerability of wireless sensor networks.

To evaluate the durability of high-performance fibers in extreme environments, this study compared the aging resistance behaviors of heteroaromatic polyamide fiber (aramid Ⅲ) and poly-p-phenylene benzobisoxazole (PBO) fiber in 30% (mass fraction) sulfuric acid (H₂SO₄) and sodium hydroxide (NaOH) solutions. Experiments were conducted under two temperature conditions (25 ℃ and 80 ℃) to systematically analyze the performance degradation laws and intrinsic mechanisms of PBO fiber in acidic and alkaline environments. The results show that PBO fiber exhibits superior acid and alkali resistance compared to aramid Ⅲ fiber. Elevated temperature significantly accelerates the aging rate, with the degree of performance degradation at 80 ℃ being much greater than that at 25 ℃. The corrosive effect of the acidic environment (H₂SO₄) on PBO fiber is more severe than that of the alkaline environment (NaOH). The amide bonds in aramid Ⅲ fiber are prone to hydrolysis, while the benzoxazole ring structure of PBO fiber endows it with higher chemical stability. The research findings provide important references for fiber material selection in applications such as chemical protection and high-temperature filtration.

To enhance the accuracy of wind speed simulations using S transform (ST), this paper proposed a high-precision data-driven approach based on multivariate empirical mode decomposition (MEMD) for nonstationary wind speed simulations in the field of structural wind engineering. A set of measured nonstationary wind speeds with multiple variables was selected. Intrinsic mode functions (IMFs) were obtained via MEMD and subjected to ST. The correlation between multiple variables was determined by employing a proper orthogonal decomposition (POD). Inverse ST (IST) was applied by incorporating random initial phases to generate simulated wind speeds. A time-frequency analysis was conducted to evaluate the proposed method. The results demonstrated that the proposed method effectively retained the energy characteristics of nonstationary wind speeds in the time domain. The amplitude distributions of the resulting ST coefficients closely resembled that of the measured wind speeds in the time-frequency domain. Quantitative comparisons of the average power spectrum confirmed the superior simulation accuracy of the proposed method compared with the ST simulation method based on the time-frequency power spectral density (TFPSD).

A hybrid turbulence simulation method combining Reynolds-averaged Navier-Stokes (RANS) and large eddy simulation (LES) was proposed based on the lattice Boltzmann method (LBM). RANS/LES-LBM method used a mixed-length RANS turbulence model to solve the problem of large errors in the conventional Smagorinsky model near the wall. Based on the method, a set of LBM parallel programs was independently developed for the hybrid turbulence model. Cylindrical, NACA0012 airfoil flow, and 30P30N three-segment airfoil flow problems were numerically calculated. Calculation results showed that RANS/LES-LBM method improved the error near the wall, had higher calculation accuracy, and exhibited good stability for complex high-Reynolds number flows. LBM paralled program used the OpenMP programming mode for parallel computing and showed good speed-up ratio, scalability, and other parallel performances. LBM multilayer meshes were also studied, which laid the foundation for the numerical simulation of complex geometric flow problems in the future.

This paper studied a class of fluid models with non-local effects, which consisted of compressible Euler equations coupled with incompressible Navier-Stokes equations, where the communication kernel of the non-local terms had a fractional Laplacian operator structure. Euler equations were reconstructed into a hyperbolic system with symmetric structure. After overcoming the nonlinear properties of non-local terms, the local well-posedness theory and regularity criterion were established for the initial value problems of such models by using the method of energy estimation.

Compared with traditional geogrids, 3D-printed geogrid technology can be printed using biointerpretive plastics to achieve waste utilization, which is environmentally friendly and can also be personalized. Through indoor pullout tests and image analysis technology, the influence of different mesh shapes, reinforcement node heights, and node arrangements on the pullout performance of 3D-printed geogrids was studied, and the shear zones of different geogrid-soil interfaces and interfacial soil particle transport laws were analyzed. The results show that the maximum pullout force and range of the shear zone of ageogrid-soil interface increased with the node height. When the node heights were the same, the maximum pullout force and shear zone under the bilateral node arrangement were greater than those under the unilateral node arrangement. The maximum pullout forces of geogrids with different mesh shapes were in descending order: quadaxial, triaxial, and biaxial geogrids. However, the order for the shear zones was the opposite. This study provides a theoretical basis for the structural optimization of 3D-printed geogrids.

Threaded-group piles are widely used in clay, silt, and sand formations owing to their high bearing capacity. However, current research on threaded piles mainly focuses on single piles, and the group pile effect and variable cross-section effect have not yet been sufficiently investigated. In this study, the group pile effect of threaded group piles with different pile numbers, spacings, and lengths and the variable section effect of threaded single piles were investigated using a model test combined with the digital image correlation (DIC) technique. This study shows that: (1) the maximum vertical and horizontal displacements of sandy soil around the threaded ring occur at the threaded ring and its lower notch, respectively. The greater the number of threaded rings, the greater is the value-added bearing capacity and the smaller is the benefit of the increase, and the mechanism of the variable section effect of a threaded pile is closely related to the development of its damage surface. (2) The horizontal displacement between group piles increases and then decreases in the process of pile compression, and the vertical displacement is transferred from the top to the bottom of the arch. At the end of pile pressing, the vertical displacement vectors of the sand between the group piles are superimposed on each other, and the horizontal displacement vectors are weakened by each other. (3) The group pile effect increases with an increase in the pile number and pile length. As the pile distance increased, the pile side and pile end resistances gradually became stronger, and the group-pile effect decreased. The larger the settlement, the smaller is the group pile effect, which reveals the interaction mechanism between the soil and threaded pile and provides a theoretical basis for improving the bearing performance of threaded group piles.