Ceramics exposed to underwater environments for prolonged periods are vulnerable to physical, chemical, and biological corrosion. X-ray fuorescence（XRF）spectroscopy, scanning electron microscope-energy dispersive X-ray (SEM-EDX) spectrometry, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and steady-state fluorescence photoluminescence (PL) spectroscopy were used to analyze the microstructure and structural composition of the two green-glazed ceramic samples salvaged from the Yangtze Estuary II shipwreck. The results revealed that fabrication of the green-glazed ceramic samples involved applying a low-temperature green lead glaze on the surface of a combined white matrix and transparent ceramic layer mainly composed of quartz and mullite, which were ¯red at high temperatures. On the green-glazed ceramic samples recovered from sediments in the Yangtze Estuary, corrosive pits, crack extensions, and corrosive products were observed mainly comprising Pb(OH)Cl caused by microbial and chemical changes on the surface of the green-glazed layer. The corrosive substances were assumed to have contributed to the continuous expansion of cracks in the green-glazed layer, which had penetrated the interface between the green-glazed layer and the connecting transparent ceramic layer. Moreover, the cracked region of the green-glazed layer and the interface between the transparent ceramic layer and the green-glazed layer contained highly hygroscopic salts, including NaCl, CaCl2, Na2SO4 and CaSO4. The osmotic pressure of these salts and the swelling effect attributable to the absorption of water had accelerated the detachment of the green-glazed layer. These finndings will make a considerable contribution to furthering the understanding of the corrosion and glaze detachment of salvaged ceramics and provide scientific evidence for the protection of salvaged ceramics.

Autonomous detection of underwater shipwreck based on side scan sonar (SSS) is the key research direction of underwater archaeology. The limited quantity of underwater targets hinders the training of the detectors. To address this issue, we employ artificial intelligence-generated content (AIGC) technology based on stable diffusion model (SDM) to supplement scarce SSS target instances. By comparing the effects of various generative techniques, we demonstrate the potential of AIGC technology in the field of underwater shipwreck detection. Based on this technique, we propose a data enhancement method without additional optical data and manual annotation, called automatic diffusion generation (ADG), which can be used to achieve high precision underwater shipwreck detection. On the YOLOv8n, the detector trained with this method can achieve 95.0% precision and 96.3% recall for underwater shipwreck detection, exceeding 1.5% and 1.8% of the detector trained with only the original data. On the Faster RCNN, this method can also further improve the detector accuracy, achieving 94.8% precision and 97.3% recall.

Sandstone grottoes, a typical type of grotto, face varying degrees of weathering from long-term exposure to natural environments and human activities. Previous studies generally have typically used single-parameter detection techniques to evaluate the degree of weathering of sandstones grottoes. However, these single indicators often fail to fully reflect real weathering conditions. To address this limitation, we conducted simulated weathering experiments under different environmental conditions and prepared sandstone samples with varying degrees of weathering. Several indicators, including mass, ultrasonic velocity, magnetic susceptibility, and chemical element content, were used to characterize the samples. Based on the analytic hierarchy process (AHP) and principal component analysis (PCA), a comprehensive multi-indicator assessment of the degree of weathering of the grotto sandstones was conducted from both subjective and objective perspectives. The results showed that the comprehensive weathering scores obtained by the AHP and PCA methods were highly consistent for sandstone samples with different weathering types and degrees. Compared to single-parameter detection indicators, the comprehensive method proposed in this study exhibited a stronger correlation with the actual weathering process of sandstone, providing a reliable approach for accurately assessing the degree of weathering in sandstone grottoes.

High-valent iron species (HVIS) have good application prospects in iron-based catalytic-induced advanced oxidation processes (AOPs) for various water treatments. How-ever, existing studies lack clarity regarding the generation, control, and identification of HVIS in AOPs. Additionally, there is a dearth of organized analyses and summaries of the degree of contribution of HVIS to pollutant removal and the underlying reaction mechanisms. These limitations can potentially hinder the practical application of AOPs that rely on high-activity HVIS to achieve high-performance long-term remediation. Therefore, this study focused on the generation, control, and main influencing factors of HVIS by iron-based catalysis, as well as their identification methods and reaction mechanisms with typical pollutants. The aim was to provide theoretical support and references for the future development and application of AOPs based on HVIS.

To investigate the effects of the pore structures of carbon fiber preforms on the densification efficiency of carbon/carbon materials, three types of three-dimensional orthogonal preforms with different weaving parameters were investigated. The same chem-ical vapor infiltration (CVI) process was used to densify and study the diffusion behavior of gas in the pores within and between the fiber bundles, and the effects of different types of pores on the weight gain rate were explored. ImageJ software was used to calculate the evolution of the regularized model pores within the fiber bundles in the three types of preforms following CVI. In addition, the pore channel area and gas diffusion coefficient of the model were quantitatively calculated using a microscopic observation method. The results indicate that when gas diffuses into the pores of the fiber bundle, Fick diffusion occurs in the early stage and Knudsen diffusion dominates in the later stage. The number of pores in the bundle affects the weight gain rate in the early stage, which in turn leads to pore filling. The A3 preform with low fiber content has high inter-bundle porosity, a large-pore cross-sectional area, and a higher diffusion coefficient. The monofilaments inside the bundle are arranged in a concentric circle, which easily form closed pores during CVI. The gas mainly undergoes Fick diffusion in the pores between the fiber bundles, and the diffusion channel area and porosity affect the diffusion coefficient, which in turn affects the subsequent weight gain rate.

The electrochromic performance of sputter-prepared WO₃ thin films with an Al₂(SO₄)₃  aqueous electrolyte was investigated. The concentration of Al₂(SO₄)₃  aqueous solution was varied from 0.025 to 0.005 mol/L. As the concentration decreased, the op-tical modulation increased slightly, the response time was prolonged, and the coloration efficiency (CE) decreased slightly. However, the cycle life was significantly increased by reducing the Al³⁺ concentration. The retentions of the charge density and optical modu-lation at a concentration of 0.005 mol/L were over three times those at 0.025 mol/L. The optimal electrochromic performance of the WO₃ thin films was observed in a 0.005 mol/L Al₂(SO₄)₃  aqueous solution, with high optical modulation of 76.3% and CE of 80.14 cm²/C; reasonable response time of 10.6 and 13.6 s for coloring and bleaching, respectively; and long-term stability (102.7% retention of optical modulation after 200 cycles). Electrochemical impedance spectroscopy (EIS) suggested that the charge-transfer rate exceeding the ion mass transfer rate was conducive to the stability of the electrochromic cycle of the WO₃ thin films.

The structure and performance relationship has attracted a great many of attentions. The electronic structure and mechanical properties of the quaternary high-entropy carbide ceramic (Hf_0.25Zr_0.25Ta_0.25Nb_0.25)C and binary metal carbide systems AC(A = Hf, Zr, Ta and Nb) are studied by density functional theory calculations. By analyzing the thermodynamic properties of high-entropy compounds, it is known that (Hf_0.25Zr_0.25Ta_0.25Nb_0.25)C can form a single-phase solid solution. It can be obtained from the mechanical performance parameters that the calculated parameters roughly obey the rule of mixture, the Vickers hardness of (Hf_0.25Zr_0.25Ta_0.25Nb_0.25)C is greater than the average value of the four binary carbides that compose it; the Poisson's ratio ν and G/B value of (Hf_0.25Zr_0.25Ta_0.25Nb_0.25)C show that it is a brittle material, similar to constituent binary carbides. By analyzing their electronic structure, it was found that they are all conductors. The quaternary high-entropy carbides (Hf_0.25Zr_0.25Ta_0.25Nb_0.25)C shows an increase in conductivity, its existence covalent bonds are mainly composed of the orbital hybridization formation of C-p and A-d (A = Hf, Zr, Ta and Nb), due to the heterogeneity of coexisting chemical bonds in carbides, the mechanical properties of the material is further improved.

Through multiple stations and small sample automatic synthesis, a high-throughput alloy preparation experimental system can reduce the preparation time and cost of individual samples and improve the synthesis efficiency of materials. To elucidate the process of the new high-throughput alloy preparation and to investigate the microstructural characteristics of the alloy samples, this study used a self-designed high-throughput automatic arc melting system to prepare CuCrZr small-sample alloys, optimized the process parameters of arc melting, explored the yield rate of alloy elements, and investigated their morphologies. The study found that when the melting current was 200 A, the burn loss of the copper alloy sample was stable, the quality of the ingots was good, and the actual compositions could be deduced from the burn losses of Cr and Zr. The casting microstructures of three typical components of copper alloys (low-Cr-high-Zr, low-Cr-low-Zr, and high-Cr-low-Zr alloys) were selected for analysis. The central area of the alloy ingot was determined to be a coarse columnar crystal, and a thin fine crystal layer was present near the water-cooled area at the bottom of the copper crucible. The precipitates in the as-cast CuCrZr alloy were distributed in interdendritic gaps. The Cr-rich phase was a (Cu+Cr) eutectic phase, and the CuZr-rich phases were Cu₅₁Zr₁₄ and Cu₅Zr, which were consistent with the phase diagram and literature. Performance measurements showed that the addition of alloying elements increased the hardness of the studied alloys but reduced their electron conductivity. This study proves the feasibility and effectiveness of high-throughput small-sample alloy preparation and provides a reference for its extension to conventional sample preparation and industrial production.

: A method involving secondary electrostatic flocking was used to prepare a ver-tically aligned array of pitch-based carbon fibers. The effects of the improved electrostatic flocking method on the density, perpendicularity, thermal conductivity, and heat trans-fer of the thermally conductive materials filled with pitch-based carbon fiber arrays were studied. The results show that pitch-based carbon fibers prepared with secondary flocking exhibited a significantly improved density and vertical alignment compared with those prepared with one-time flocking under the same flocking time. Additionally, when the film was contracted by 33%, the thermal interface material achieved a high vertical thermal conductivity of 27.4 W/(m·K). The material exhibited a good vertical thermal conductivity, and the preparation process shows great promise for industrial scalability and potential applications in the field of electronic chip heat dissipation.

Biaxially textured MgO films were deposited on nontextured metal tapes via ion beam-assisted deposition (IBAD), and the effects of different ion beam energies on the biaxial texture and surface morphology of MgO were investigated. The results indicated that an increase in the ion energy in the range of 700∼1 000 eV contributed to the optimization of the texture quality of IBAD-MgO. Biaxially textured MgO films with an in-plane full-width at half-maximum (FWHM) ∆ϕ and out-of-plane FWHM ∆ω of 6^◦ and 2^◦, respectively, were obtained at 1 000 eV. In addition, the surface morphology of the MgO films did not differ significantly with an increase in the ion energy, and the root mean square (RMS) values of surface roughness (5 µm×5 µm) was in the range of 5∼6 nm. This study demonstrated that a higher Ar⁺ ion beam energy could improve the texture quality of IBAD-MgO films, which was important for the stable preparation of biaxially textured films.

A group of zirconia-based high-entropy ceramics containing Ce, Al, Y and Si was prepared using a high-temperature sintering method, and the phase structure tran-sition and optical absorption characteristics were studied. X-ray diffractometer (XRD) results showed that the cubic zirconia phase transformation was completed at 1 450 ›. Scanning electron microscopy (SEM) results showed that the doped zirconia ceramic particles exhibited grain refinement, with a minimum average grain size of 234 nm. X-ray photoelectron spectroscopy (XPS) results showed that the oxygen vacancy concentration was positively correlated with the Ce∶Zr atomic ratio. The maximum bending strength of the sintered sample was 130.32 MPa, the minimum porosity was 0.15%, the maximum visible absorption range was 513 nm, and the minimum bandgap after doping was 2.97 eV.

Nanoporous bimetals have unique three-dimensional nanostructures and synergistic optical properties, making them good candidates for surface-enhanced Raman scat-tering (SERS). A nanoporous copper-silver bimetallic SERS substrate was prepared by a dealloying process using a zirconium-copper-silver amorphous alloy as the precursor. The substrate with uniform nanopores showed excellent SERS properties. The detection limits for rhodamine 6G (R6G) and crystal violet (CV) were 10⁻¹⁶ and 10⁻¹⁰ mol/L, respectively. The substrate also exhibited good uniformity and stability. The preparation of simple, efficient, and low-cost nanoporous copper-silver provides a new approach for the realization of high-performance SERS substrates.

In order to investigate whether the stability of the underground diaphragm wall is affected by the grip strength of reinforced concrete wrapped by slurry, this paper takes the Deep Drainage Pipeline System of Suzhou River project as the background. The pull-out destructive tests were carried out based on the self-developed high-power central pull-out test device and the bottom-up mud replacement method by using large-size specimens and the same concrete and slurry ratios as the actual project. The bonding characteristics of the interface between steel, glass fibre reinforcement and concrete were analysed to reveal the effect of casting method, bond length and main reinforcement material on the bond strength under two casting environments. The results show that: (1) There is no significant difference on the concrete compressive strength of specimens cast in normal environment and in slurry, and the mean difference on the concrete compressive strength of specimens cast in the two different environments is within 3%. (2) For both steel and glass fibre reinforcement, the load-displacement curves differed between the normal environment and the mud-soaked environment; it can be divided into elastic deformation phase, plastic deformation phase and broken phase. (3) The grip force after mud immersion is less than that under normal casting conditions. As the bond length increases, the influence of mud on the grip force at the reinforcement-concrete interface gradually becomes greater, and the influence of mud on the grip force at the glass fibre reinforcement-concrete interface gradually decreases. The average bond strength after slurry immersion was significantly reduced by 19.2% for steel and 44.5% for glass fibre reinforcement. The slip values after the effect of mud immersion were less than those under normal conditions. (4) The forms of cracks produced on the specimen surfaces were classified as radial cracks, circular cracks and falling-offs of the surrounding specimens, and the formation of cracks was mainly concentrated in the normal pouring environment.

In order to investigate the formation mechanism of shear band when slope was damaged by load, an indoor model test was designed. By using the digital image correlation (DIC) method, the formation of shear bands and the progressive failure of a sandy slope were characterized and analyzed in the model test, in which failure was deliberately triggered by loading. In this paper, the discrete element software PFC3D was used to simulate a model test to further supplement and verify the DIC calculation results. The results suggest that developing a shear band is a dynamic process. At the beginning of the loading, strain localization regions were scattered around the loads. As loading continued, some of the strain localization regions connected and formed multiple shear bands, while some strain localization regions disappeared. Around the time 3/4T (i.e., T was the time when the slope reached ultimate capacity and failed), multiple shear bands transitioned into one major shear band that extended to the slope surface around time T. After time T, the horizontal displacement of the sliding body increased rapidly, and the damage phenomenon manifested as an overall downslide.

The design of struts in soft soil foundation pits is predominantly manually performed, resulting in a low level of automation. With the rapid development of computing technology, intelligent design methods have been employed to improve the efficiency of this process. To facilitate the basic implementation of automated design methods for strut layouts, an automated design approach based on graph neural networks (GNNs) was proposed. First, a graph-based representation method was established to accurately depict the beam-column topological connections. Four datasets comprising four typical strut arrangements were established. Subsequently, the GNN was trained using the aforementioned datasets. Three GNN models, including the characteristics of the connections between columns, were selected to enable link prediction of the beams between columns. Finally, the proposed method was applied to automatically generate beam structures for a secondary foundation pit planned in Shanghai. Finite element analysis was performed to validate the compatibility of the proposed methods. The results showed that the GNN-based automated design of strut layouts in foundation pits can provide rational and efficient arrangements that satisfy the regulatory design and construction requirements.

The post-earthquake evacuation process was divided into multiple periods and the casualties were transported through ambulances and helicopters. Considering the survival probability and psychological cost changes of casualties during different periods, a multiple-period dynamic fuzzy programming model for emergency medical facility locating and casualty evacuation was established to maximize the survival probability and minimize the psychological cost of casualties. The model used a triangular fuzzy number to describe the casualty uncertainty. The model was solved using Cplex and sensitivity analysis was performed using a real case based on the Wenchuan Dujiangyan earthquake. The following conclusions were obtained. To increase the survival rate of casualties and reduce psychological costs, severely injured persons should be prioritized for evacuation in the early stages of disasters, while those with mild injuries should be prioritized for evacuation in the later stages of disasters. Transport vehicles used for emergency treatment had a greater impact on the survival rate of injury casualties than those used for subsequent treatment. Temporary hospitals with a small capacity led to a decrease in the number of casualties with mild injuries, while rear hospitals with a small capacity led to a decrease in the number of those with severe injury. Excessive vehicles did not have an impact on the survival rate of casualties and psychological costs.