The zero-dimensional (0D) ordered lead-free double perovskites (DPs) Cs₂B^(IV)X₆ have recently been recognized as promising candidates in the optoelectronics domain. Their exceptional stability and environmentally benign nature position them as ideal alternatives to their toxic and unstable lead-based halide perovskite counterparts. Recent years have witnessed notable progress in the optical properties of Cs₂B^(IV)X₆, propelled by techniques such as ion doping, surface coating and ligand modification, which has been instrumental in broadening their applications in various optoelectronic domains. Herein, a comprehensive overview is provided on the recent progress regarding synthesis methods, optimization strategies, bandgap engineering, photoluminescence (PL) optimization, and device applications related to Cs₂B^(IV)X₆ materials. It also explores critical aspects including structural diversity, tunable emission, photophysical mechanisms, and material stability. Moreover, the review addresses the prevailing challenges in this field and outlines future research directions aimed at enhancing the photoluminescence quantum yield and stability of Cs₂B^(IV)X₆.

Additive manufacturing (AM) of SiC_P/Al composites has shown significant potential for expanding the application of aluminum matrix composites (AMCs) due to their outstanding mechanical properties and wear performance. However, conventional mechanically mixed powders for AM are limited due to the possible powder agglomeration and poor fluidity. In this study, the spherical SiC_P/AlSi10Mg composite powders prepared by spray granulation were employed to fabricate SiC_P-reinforced AlSi10Mg composites using laser powder bed fusion (LPBF). The impacts of laser power on microstructure evolution and wear properties of composites were systematically investigated. The results indicated that an in-situ reaction between the aluminum matrix and SiC_P during the LpBF process, resulted in the formation of particle-like and strip-like strengthening phase Al₄SiC₄. By adjusting the laser power (from 270 W to 350 W) to change the ratio of SiC_P to Al₄SiC₄, micro-defects could be effectively limited, and wear performance could be improved. Consequently, with an optimized ratio of SiC_P to Al₄SiC₄, the composite exhibited a mixed strengthening mechanism caused by the SiC_P and Al₄SiC₄ reinforcing phases. At a laser power of 310 W, the sample exhibited minimal porosity with a microhardness value reaching 265.38HV, while maintaining relatively low average friction coefficient and wear rate. In addition, compared with other studies, the hardness obtained was superior to that of the AlSi10Mg and other reported SiC_P/AlSi10Mg composites with similar volume fractions using the mixed powders.

Friction stir additive manufacturing (FSAM) is an innovative additive manufacturing (AM) method. The various heat treatment conditions of aluminum-lithium alloys using this method have not been widely discussed. In this study, the microstructure evolution and mechanical properties of FSAM 2195 aluminum-lithium alloy in different heat treatment conditions (T3 and T8) were investigated. The results demonstrated that the heat treatment state of 2195 Al-Li alloys was minimally influenced by FSAM as the FSAM temperature exceeded the solid solution temperature. After conducting a single-pass FSAM experiment, a notable grain refinement was observed in the nugget zone (NZ) region compared to the base material (BM). The average grain size of the 2195-T3 alloy decreased from 6.1 to 2.9 µm, while the proportion of high-angle grain boundaries increased from 16.5% to 43.9%. Similarly, the average grain size of the 2195-T8 alloy decreased from 8.9 to 2.8 µm, with an increase in high-angle grain boundary from 37.6% to 59.2%. The tensile strength of the 2195-T3 Al-Li alloy reached 466 and 478 MPa in the NZ of single-pass and lap experiments, respectively. In comparison, the tensile strength of the 2195-T8 Al-Li alloy in the NZ could reach 452 and 481 MPa in single-pass and lap experiments, respectively. These results demonstrate the significant improvements in microstructure and mechanical properties were achieved through the FSAM process.

This work investigated tribological behavior and corrosion resistance of laser cladding (LC) Ti₅₀Nb₁₅V₁₅Zr₅Cr₅Al₁₀ high-entropy alloy (HEA) coatings on Ti6Al4V substrates. Microstructural characterization illustrated that there was only body centered cubic phase in the HEA coating. Besides, the coatings of different laser power all exhibited obviously higher hardness than the substrate. It is illustrated that the microstructure of the HEA coatings is composed of body centered cubic phase, and the temperature gradient contributes to the distribution difference between the equiaxed and columnar grains. Meanwhile, the relationships between the tribological behavior, corrosion resistance and alloying elements have been illustrated. The HEA coating with 2200 W holds the best wear and corrosion resistance. During the friction process, there are many oxides formed at high temperatures, and adhesive wear contributes most to the wear mechanism of the coatings. The wear volumes of the HEA coatings are only 24.7% to 45.5% of that of the Ti6Al4V substrate. Due to the alloying elements like Cr and Al, there is dense passive film formed during the corrosion process, thereby leading to better corrosion resistance of the coatings. The corrosion rates of the HEA coatings with 2200 W and Ti6Al4V substrate are 5.34×10⁻³ mm/a and 2.69×10⁻² mm/a, respectively.

The creep deformation and mechanical properties of 2219 aluminum alloy were experimentally investigated under both tension and compression at the temperature of 165 °C for different time. The results indicated that the creep deformation under tensile stress was greater than that under compressive stress. As the stress level increases, the compressive creep rate showed more significant increase. The yield strength after compressive stress creep-ageing was higher than that after stress-free ageing, with the lowest strength observed in the tensile-aged sample. Overall, the average phase length after compressive stress creep-ageing was larger than after tensile stress ageing. Under tensile stress, the number and size of precipitates at small angles to the stress direction were larger than those perpendicular to the stress direction. In contrast, under compressive stress, this relationship was reversed, and the preferential orientation of phases became more pronounced with ageing time. A unified, physics-based creep-ageing constitutive model, accounting for the orientation of precipitation, was developed for both tensile and compressive stress conditions. The predicted results were in good agreement with the experimental data. These findings, along with the developed model, provide a theoretical and simulation basis for precise creep-ageing forming of components under complex stresses.

In this study, AZ31 Mg alloy sheets were processed by a severe plastic deformation (SPD) technique called forging-bending repeated deformation (FBRD). The effect on the microstructure and microhardness of AZ31 Mg alloy through FBRD was investigated with increasing temperature treatment and a 90° cross route. The results reveal that the effective strain increases with the number of passes. The flow uniformity is effectively enhanced due to alterations in shear deformation direction. After four passes of deformation, the average grain size is refined by 79.3% compared to the initial specimen. The grain refinement mechanism predominantly originates from the synergistic effects of discontinuous dynamic recrystallization (DDRX), continuous dynamic recrystallization (CDRX), and twinning-induced recrystallization (TDRX). The formation of

After the hot deformation sample of Ti-10V-2Fe-3Al alloy was treated by solid solution in the α+β two-phase region, the coarse β grains that often appeared in the β single phase region were observed in the local region, indicating that the abnormal grain growth occurred in the local microstructural region, and the macrostructure also showed abnormally coarse grains (ACGs). The dynamic recrystallization (DRX) behavior of Ti-10V-2Fe-3Al titanium alloy was systematically investigated through hot compression tests on the Gleeble-3800 system. The DRX model of β grains was established, and the quantitative correlation between DRX characteristics and the appearance of ACG was clarified. Based on these results, a numerical simulation platform was developed to realize the visual prediction of ACG distribution. The results show that the increase of deformation temperature and the decrease of strain rate both contribute to a significant increase in the grain size (d_DRX) and volume fraction (X_DRX) of DRXed grains. However, the proper X_DRX and smaller d_DRX at low deformation temperature and high strain rate make the macro and microstructure show ACGs after solid solution. Interestingly, if the DRX degree is excessive or insufficient, ACGs cannot be produced, indicating that ACGs are solid solution products based on the appropriate DRX degree. According to the flow curves and statistical results of microstructure, the quantitative model of DRX kinetics and DRX grain size model were constructed, and the quantitative criterion model that is related to the formation of ACG with grain size (d_DRX) and volume fraction (X_DRX) of DRXed grains as the key parameters was established, i. e., d_DRX≤2.60 µm, 72.5%≤X_DRX≤87.9%. By integrating the subroutine of coarse grain criterion, the isothermal compression process of cylindrical samples and the actual die forging process of H-shaped parts were simulated by DEFORM-3D software of finite element (FE), respectively, and the visual prediction of the distribution of macroscopic ACGs was realized. There is a good consistency between the tested results and the simulated results, indicating a strong correlation between macroscopic ACGs and microscopic DRX.

Eco-friendly electrocatalytic nitrogen reduction reaction (NRR) is aimed to replace the traditional polluting industrial process, but NRR needs electrocatalysts with high selectivity and activity to boost desired NH₃ yield rate and Faradic efficiency (FE). In this work, high-entropy sulfides (HES) (FeCoNiMoM)S_x (M=Cr, Cu, Mn) were synthesized via a two-step solvothermal method. The optimized composition for HES is (FeCoNiMoCr)S_x, with promising NRR performance that NH₃ yield rate reached 47.97 µg/(h·mg_cat) at −0.7 V vs RHE and FE was 26.1% at −0.4 V vs RHE. Comprehensive characterization and electrochemical testing were performed to investigate the effects of the metal component on NRR performance. It reveals that (FeCoNiMoCr)S_x shows more intense charge transport, more electrocatalytic active sites, higher selectivity, etc, resulting from the electron transport and element synergy of HES. Also, it is proved to have targeted NRR selectivity and limiting competitive hydrogen evolution reaction. The results offer promising guidance for further improving the NRR electrocatalysts based on transition elements.

The AlMgScZr high-strength aluminum alloy fabricated by selective laser melting (SLM) technology exhibits a “bimodal microstructure”, resulting in significant non-uniform deformation during thermal deformation. This study investigates the flow behavior of SLM-processed AlMgScZr aluminum alloy utilizing the Gleeble-1500D thermal simulation machine. The true stress–strain curves were amended based on the friction theory. Through determining the Zener-Hollomon parameters, the correlation between flow stress, deformation temperature, and strain rate during the high-temperature thermoplastic deformation of SLM-processed AlMgScZr aluminum alloy with a “bimodal microstructure” was established. In addition, the microstructural evolution during thermal deformation was analyzed. The results indicated that the predicted flow stress values obtained from the Arrhenius constitutive equation with coupled correction of thermal deformation parameters closely matched the experimental values. The correlation coefficient and the average absolute relative error of the corrected model were 0.999 and 2.766%, respectively, accurately predicting the thermoplastic deformation behavior of SLM-processed high-strength aluminum alloy with a “bimodal microstructure”. Furthermore, hot processing maps at different strains were established, identifying stable and unstable regions under different deformation conditions. Microstructural observations revealed different thermal deformation mechanisms under various deformation temperatures. Specifically, dynamic recrystallization characteristics dominated the microstructure at lower temperatures (300–360 °C), while dynamic recovery was dominant at higher temperatures (390–500 °C).

Herein, a sub-micron lanthanum zirconate ceramic (La₂Zr₂O₇, LZO) with a pyrochlore structure was prepared by the sol-gel and high temperature sintering methods. The corrosion behavior and mechanism of calcium-ferrum-alumina-silicate (CFAS) powder (33CaO: 10FeO_1.5: 13AlO_1.5:44SiO₂) on the sub-micron LZO ceramic at 1673 K was investigated. The results indicate that the average grain size of sub-micron LZO ceramic was 895 nm. The CFAS melt rapidly diffused into the interior of the LZO ceramic wafer and reacted with it to generate high melting point rod-shaped Ca₂La₈(SiO₄)₆O₂ apatite and m-ZrO₂ phases, which can effectively hinder further diffusion of CFAS melt, resulting in a slow increase in corrosion depth with corrosion time. After 30 h of CFAS corrosion at 1673 K, the corrosion depth of the LZO ceramic wafer was only 160.3 µm, demonstrating its excellent high-temperature resistance to CFAS corrosion.

Arsenic (As) contamination of groundwater is a serious global issue requiring effective and sustainable remediation strategies. For long-term As immobilization, this study explores the potential of in-situ magnetite precipitation, induced by anaerobic nitrate-reducing Fe(II) -oxidizing (NRFO) bacteria. A nitrate-intercalated layered double hydroxide (NO₃-MgFe LDH) was introduced to provide nitrate as an electron acceptor for Fe(II) bio-oxidation and serve as an iron-based precursor in magnetite formation. The experimental results showed that NO₃-MgFe LDH was transformed into green rust (GR) in the presence of Fe(II) and HCO₃⁻. Meanwhile, 0.5 g/L of NO₃-MgFe LDH released cumulatively about 1.21 mM of nitrate within 12 h, promoting the transformation of GR into magnetite induced by Acidovorax sp. BoFeN1. As a result, the aqueous As concentration decreased from 2 mg/L to <0.008 mg/L, with approximately 70% of As confined in recalcitrant Fe oxides, suggesting high potential for long-term As immobilization. Environmental factors influenced the transformation process: a lower Fe(II) concentration (0.5 mM) delayed GR formation, while varying HCO₃⁻ concentrations (2.5–10 mM) had minimal effect. Subsequently, an elevated As level (5 mg/L) inhibited the bio-formation of magnetite, leading to lepidocrocite as the dominant mineral phase. Given the stability of magnetite, this study provides a cost-effective and environmentally friendly strategy for the durable in-situ remediation of As-contaminated groundwater.

Iron removal from zinc leachate in hydrometallurgy produces large volumes of low-grade, impurity-laden iron waste, posing significant environmental challenges. Magnetite precipitation offers a novel method for iron removal and resource recycling in zinc hydrometallurgy. However, the chemical similarity between ferrous and zinc ions, along with high zinc concentrations, causes zinc co-precipitation, challenging its application. To address this issue, this study utilized electron microscopy to observe key intermediate products in magnetite crystallization and employed EXAFS (extended X-ray absorption fine structure) to analyze their evolutionary mechanisms and zinc-binding configurations. The results indicate that the intermediate products during magnetite formation are sequentially green rust, feroxyhyte (δ-FeOOH), and weakly crystalline nanoparticles, and further analysis revealed that their transformation follows the dissolution-recrystallization mechanism. Furthermore, it was found that intermediate products such as green rust exhibit strong binding with zinc (via adsorption and lattice substitution), which was confirmed as a significant reason for the difficulty in separating zinc from magnetite. This study elucidates the transformation process of intermediate products during magnetite formation and, for the first time, reveals the binding configurations of zinc with these key intermediate products. This has significant implications for the development and optimization of new technologies for the efficient separation of iron and zinc during the magnetite precipitation process.

In this study, the effect of Cu²⁺ on the cassiterite and calcite flotation using octanohydroxamic acid (OHA) as collector was investigated through flotation tests, solution reaction tests and calculation, zeta potential measurements, XPS analysis and residual reagent concentration measurements. Results indicated that Cu²⁺ played an activation role on cassiterite flotation but a depression role on calcite flotation. The copper cations were adsorbed on the cassiterite surface by forming a Cu—O bond, and the pre-adsorbed copper cations and the OHA-Cu complexes promoted the adsorption of OHA on the cassiterite surface. Thus, cassiterite flotation was activated. The dissolved HCO₃⁻ in the calcite pulp underwent a double hydrolysis reaction with copper cations (Cu²⁺, CuOH⁺, Cu₂(OH)₂²⁺ and Cu₃(OH)₄²⁺) to form CuCO₃. Some copper cations were adsorbed on the calcite surface as well, but some adsorbed Cu²⁺ on the calcite surface was desorbed by bonding with OHA, and most of OHA was consumed by Cu²⁺, basic copper carbonate and copper hydroxide. The residual OHA in the pulp was not sufficient for flotation, so calcite flotation was depressed. Finally, a model of the reaction mechanism of Cu²⁺ and OHA on the cassiterite and calcite surfaces was established.

The “upper coal and lower bauxite” resource distribution pattern is widespread in China, where mining of the overlying coal seam significantly alters the stress environment of the underlying bauxite layer. This study investigates the stability of inclined bauxite pillars under the influence of stress redistribution caused by coal seam extraction. A theoretical model is developed to calculate the direction and magnitude of principal stresses in the inclined floor strata, and a pillar stability analysis model is established that considers the effect of principal stress rotation. The research employs a combination of theoretical analysis, physical modeling, numerical simulation, and field observation. Findings indicate that stress rotation is most pronounced at both ends of the coal seam goaf, with the maximum clockwise and counterclockwise rotation angles of 19° and −40°, respectively, observed in the bauxite layer. Inclined bauxite pillars are subjected to combined compressive and shear loading. Under such conditions, clockwise rotation of principal stress increases the shear-to-normal stress ratio, thereby reducing pillar stability. Pillars located beneath the coal wall are the first to fail due to stress concentration and principal stress rotation, which can trigger a cascade of instability among the adjacent pillars. The findings provide a theoretical basis and practical guidance for ensuring the safe co-mining of coal seams and bauxite resources.

Rockburst is a common disaster in deep underground engineering, which seriously impacts project construction safety. Understanding its causes and burst resistance mechanism is of significance for rockburst prevention and mitigation. We developed a new type of high strength, large elongation, and strong energy-absorbing material, and conducted comparative tests on both basic and anchored rock specimens with such material. We analyzed the rockburst process, energy release and peak stress of the rock, and force and deformation withstood by the energy-absorbing bolts. The experimental results show that the energy reduction rate of the rocks reinforced by energy-absorbing bolts is more than 80%, compared with that of the basic rock. The force exerted on the energy-absorbing bolts increases suddenly when the rockburst occurs, and the strength utilization rates of the energy-absorbing bolts under strain rockburst and impact rockburst conditions are 73.3% and 61.2%, respectively. Rockburst also causes non-uniform shear deformation of the anchor bolt. Based on the rockburst energy criterion, the peak stress of the anchored rock is 2.2 times and 2.5 times the uniaxial compressive strength of the rock, respectively, under strain rockburst and impact rockburst conditions. The energy required for rockburst is 396.0 and 478.4 kJ/m³, respectively. The energy-anchoring bolts can effectively reduce the likelihood of rockburst. The results can provide a reference for support design for burst-prone rock in underground engineering.

Composite rock layers are widely present in mining and tunnel construction projects, and are prone to dynamic tensile failure along bedding planes under dynamic disturbances. To ensure engineering safety, it is necessary to conduct research on the dynamic tensile characteristics under different working conditions. Considering the difficulty of on-site sampling, composite rock samples were prepared with cement mortar, and dynamic Brazilian splitting tests were carried out using split Hopkinson pressure bar (SHPB) equipment, a high-speed camera, and PFC^2D numerical software to explore their dynamic tensile properties under dynamic disturbance under different strength ratios and other factors. The results show that the dynamic tensile strength of samples exhibits a rising trend with the strength ratio and strain rate growth. As the incident angle increases from 0° to 90°, the stress contour deflects transform from center-splitting failure to tension-shear combined failure and back again. The influence of the incident order in different lithology rocks on the dynamic tensile strength of composite samples is controlled by strain rate, and when the strain rate increases to 400 s⁻¹, the difference in strength due to the sequence of incident stress waves is within 5%. Based on PFC^2D, the strength ratio of composite samples has a certain influence on the distribution of microfractures. With strength ratios equaling 1.5 or 2.0, the cracks are mainly concentrated on the softer material side, while a large number of cracks are distributed on both sides of the bedding plane with a strength ratio equal to 1.2.

Based on MTS Landmark 370.50 rock dynamic and static load fatigue test system and acoustic emission (AE) monitoring method, the damage characteristics and energy evolution law of high static load coal-rock combination (CRC) under the influence of dynamic load parameters were studied. The main results are as follows: 1) Dynamic load increases the rheological properties and damage fracture development of CRC. With the increase of the amplitude and frequency of the dynamic load, the number of dynamic load cycles required for the failure of the CRC decreases, the irreversible strain increases, and the failure of sample accelerates; 2) The AE positioning events during the loading process of the specimen decrease with the increase of the dynamic load amplitude, and increase with the increase of the dynamic load frequency; 3) The fractal dimension, total energy and cumulative elastic energy of the broken particles of the CRC increase with the increase of the amplitude and frequency of the dynamic load. The fractal dimension corresponding to the increase of the dynamic load frequency is larger, and the energy and cumulative elastic energy corresponding to the increase of the dynamic load amplitude are larger.

Subgrade settlement is a common issue in soil ground within earthquake-prone regions, posing a threat to the safe operation of train-slab track coupled system (TSCS) in high-speed railways (HSRs). This study aims to analyze the mechanical behavior evolution of TSCS under subgrade settlement and earthquake excitation. The refined numerical model of slab track under subgrade differential settlement is established. The short settlement wavelength of 10 m causes the separation between the base and subgrade. The dynamic model of TSCS under subgrade settlement and earthquake excitation is developed. The dynamic response of TSCS exhibits more pronounced fluctuations under the combined effects of subgrade settlement and earthquake excitation than under the effects of settlement or earthquake alone. The evaluation indexes for the running safety of train on slab track under different settlement wavelengths exhibit varying degrees of increase with settlement amplitude and are particularly sensitive to the short settlement wavelength of 10 m. The wheel unloading rate and derailment coefficient of TSCS increase with earthquake intensity. Under the settlement wavelength of 10 m and amplitude of 20 mm, the wheel unloading rate of TSCS exceeds the allowable limit when the earthquake intensity exceeds 0.17g, and the derailment coefficient exceeds the allowable limit when the earthquake intensity surpasses 0.29g.

Structural damage detection is hard to conduct in large-scale civil structures due to enormous structural data and insufficient damage features. To improve this situation, a damage detection method based on model reduction and response reconstruction is presented. Based on the framework of two-step model updating including substructure-level localization and element-level detection, the response reconstruction strategy with an improved sensitivity algorithm is presented to conveniently complement modal information and promote the reliability of model updating. In the iteration process, the reconstructed response is involved in the sensitivity algorithm as a reconstruction-related item. Besides, model reduction is applied to reduce computational degrees of freedom (DOFs) in each detection step. A numerical truss bridge is modelled to vindicate the effectiveness and efficiency of the method. The results showed that the presented method reduces the requirement for installed sensors while improving efficiency and ensuring accuracy of damage detection compared to traditional methods.

This study investigates the fracture behavior of clay-rich mudstone under varying temperature and pressure conditions, which is crucial for the safety of geological structures. It focuses on three fracture types: pure mode I tensile fractures, pure mode II tensile fractures, and shear fractures, examining specimens at room temperature (RT) and after thermal treatments at 250 and 500 °C. The findings reveal that increasing temperatures makes the mudstone more brittle, enhancing fracture velocity, toughness, load-bearing capacity, roughness, and the fracture process zone (FPZ) radius. Notably, tensile fractures induced under pure mode II displayed the highest velocities, while shear fractures exhibited the lowest velocities, smoothest surfaces, and greatest resistance to failure. The application of a confining pressure of 4 MPa significantly improved shear fracture toughness by 119.7%, 98.5% and 71.9% at RT, 250 °C and 500 °C, respectively, and reduced roughness by 8.2%, 22.4% and 30.4%. This research offers a novel, comprehensive view of how temperature and pressure impact fractures in mudstone sensitive to temperature due to its high clay content and water affinity. The findings provide valuable insights applicable to geothermal energy, oil and gas exploration, and underground construction, thereby enhancing the understanding of fracture mechanics in geological contexts.

In the corrosive environment of carbonaceous mudstone, the mechanical properties of grouting materials in the anchorage section of anchor bolts continue to deteriorate. In response, a cement-based modified anchoring grouting material (MAGM) with high corrosion resistance was developed. The results reveal that compared with those of ordinary Portland cement (OPC) grouting material, the compressive strength, tensile strength, and shear stress peak of the MAGM increased by 85.9%, 44.4% and 45.4%, respectively, after 28 d of corrosion in a carbonaceous mudstone solution. Waterborne epoxy resin and curing agent create a network membrane structure under the action of nano-Al₂O₃ to protect the cement hydration products. In the corrosive environment of carbonaceous mudstone, corrosion products formed on the surface of the stone body have adsorbed onto the reticular membrane structure, filling the pores of the stone body and slowing the erosion rate of ions. After 365 d of application of MAGM and OPC in the corrosive environment of a carbonaceous mudstone slope, the peak shear stress of MAGM is, on average, 55.3% greater than that of OPC.

To elucidate the influence of confining pressure on microcrack evolution and macroscopic failure mechanisms in granite, a multi-perspective approach was adopted. This approach combined triaxial compression tests, acoustic emission (AE) monitoring, and PFC simulations. The results show that: 1) Confining pressure exhibits a pronounced linear correlation with both yield strength and compressive strength. The enhancement of confining pressure significantly improves the deformability of granite and promotes a progressive shift in failure mechanism from brittle rupture to ductile deformation; 2) Increasing confining pressure elevates the stress threshold for microcrack initiation and suppresses crack propagation. As a result, the proportion of shear cracks increases (based on AE analysis) from 18.71% to 61.2%, marking a transition in the dominant failure mode from tensile to shear; 3) Confining pressure facilitates the development of grain boundary shear cracks (GBSCs), establishing the primary damage pathways. In addition, local stress concentrations under high confinement conditions trigger intragranular cracking. This highlights the regulatory effect of confining pressure on microcrack evolution.

Molybdenum tailings are the solid waste left from ore processing, which damages soil and water resources. To address that, molybdenum tailings (MTs) powder obtained from molybdenum tailings sands was processed as an admixture. Compared with moisture-cured conditions, the influence of MTs on the steam-cured mortar’s mechanical properties, surface and internal pore characteristics, and microscopic morphology was investigated. The results show that steam-cured mortar containing appropriate MTs can still have high early strength. When the content of MTs doesn’t exceed 15%, the mechanical strength of mortar steam-cured for 3 d can reach 85% of that of corresponding mortar moisture-cured for 28 d, and that of mortar steam-cured for 28 d isn’t lower than 90% of that of pure cement mortar. The proportion of harmful pores (HFP) and more harmful pores (MHFP) and most probable pore diameters (MPD) on the mortar surface containing MTs steam-cured for 28 d are significantly decreased. When MTs’ content is 15%, the proportion of HFP and MHFP on the surface of paste is decreased by 71.4% and 72.2%, respectively, with MPS decreasing from 12.7 nm to 10.8 nm. SEM analysis shows that the surfaces of steam-cured paste containing 15% MTs have more hydration products and dense microstructures. The effect of pozzolanic and dense filling of MTs effectively refines the pore structure, reducing the large pore-size pores.

It is a good practice to change the site soil properties when dealing with inappropriate soils in geotechnical engineering, referred to as soil improvement. This study investigated the effects of epoxy resin LR202 stabilizer (5 wt% of soil as an optimum percentage) and glass fibers (0 wt%, 0.4 wt% and 0.8 wt% of stabilized soil) as reinforcement on silty sand’s durability. For this purpose, the unconfined compressive strength test (12 tests), durability test (12 tests), ultrasonic pulse velocity (UPV) test (48 tests), and standard compactions test (5 tests) were performed. The results of this study showed that the addition of epoxy resin improves the durability of silty sand soil. The stabilized samples containing 5 wt% epoxy resin resisted 12 freeze-thaw cycles, and the sample behavior was enhanced by adding 0.4 wt% and 0.8 wt% fibers to the stabilized samples. Hence, the samples stabilized with epoxy resin exhibited acceptable behavior under freeze-thaw durability cycles. This indicates that epoxy resin stabilizer is appropriate in areas with possible frost and exhibits good behavior. The results of the UPV test showed that it could be used as a non-destructive test to control the durability of epoxy resin-stabilized soils.

The determination of discontinuity shear strength is an important concern in rock engineering. Previous research mainly focused on the shear behavior of discontinuities with identical joint wall compressive strengths (DIJCS). However, the shear behavior of discontinuities with different joint wall compressive strengths (DDJCS) and 3D surface morphology had been rarely reported. In this study, matched mortar DDJCSs were prepared using 3D printed photosensitive resin molds. Direct shear tests were carried out under three kinds of normal stress (ranging from 0.5 to 3.0 MPa) to analyze the shear strength and contact zones of DDJCS during shearing. The results show that the contact zones of DDJCS during shearing are scattered in the steep zones facing the shear direction. It is verified that Grasselli and Develi’s directional surface roughness characterization method can be used to predict the shear-induced potential contact zones of DDJCS. When the critical apparent dip angle is equal to the peak dilation angle, the predicted contact area agrees well with the actual contact area. A 3D directional roughness parameter with clear physical meaning was introduced to characterize discontinuity surface roughness. A 3D modified joint roughness coefficient-joint wall compressive strength (JRC-JCS) criterion that can both predict the shear strength of DDJCS and DIJCS was proposed based on the newly defined roughness parameter. The proposed criterion was validated by 77 direct shear tests presented by this study and 163 direct shear tests presented by other investigators. The results show that the proposed criterion was generally reliable for the peak shear strength prediction of DDJCS and DIJCS (within 16%). It is also found that the new criterion can capture the anisotropy of the peak shear strength of DDJCS. The anisotropy of DDJCS decreases with increasing normal stress. It should be noted that the anisotropy of the shear strength of DDJCS was not investigated experimentally, and further experiments should be conducted to verify it.

Steep bedding slopes are widely distributed in Southwestern China’s mountainous regions and have complex seismic responses and instability risks, causing casualties and property losses. Considering the high-seismic-intensity environment, the dynamic failure evolution and instability mechanism of high-steep bedding slopes are simulated via the discrete element method and shaking table test. The dynamic response characteristics and cumulative failure effects of slopes subjected to continuous ground motion are investigated. The results show that the dynamic response characteristics of slopes under continuous earthquakes are influenced by geological and topographic conditions. Elevation has a distinct impact on both the slope interior and surface, with amplification effects more pronounced on the surface. The weak interlayers have different influences on the dynamic amplification effect of slopes. Weak interlayers have dynamic magnification effects on the slope surface at relative elevations of 0–0.33 and 0.82–1.0 but have weakening effects between 0.33 and 0.82. Moreover, the weak interlayers also have controlling effects on the dynamic instability mode of slopes. The characteristics of intergranular contact failure, fracture propagation, and displacement distribution are analyzed to reveal the dynamic failure evolution and instability mechanism through the discrete-element model. The dynamic instability process of slopes includes three stages: fracture initiation (0−0.2g), fracture expansion (0.2g–0.3g), and sliding instability (0.3g–0.6g). This work can provide a valuable reference for the seismic stability and reinforcement of complex slopes.

Accurate estimation of lithium battery state-of-health (SOH) is essential for ensuring safe operation and efficient utilization. To address the challenges of complex degradation factors and unreliable feature extraction, we develop a novel SOH prediction model integrating physical information constraints and multimodal feature fusion. Our approach employs a multi-channel encoder to process heterogeneous data modalities, including health indicators, raw charge/discharge sequences, and incremental capacity data, and uses multi-channel encoders to achieve structured input. A physics-informed loss function, derived from an empirical capacity decay equation, is incorporated to enforce interpretability, while a cross-layer attention mechanism dynamically weights features to handle missing modalities and random noise. Experimental validation on multiple battery types demonstrates that our model reduces mean absolute error (MAE) by at least 51.09% compared to unimodal baselines, maintains robustness under adverse conditions such as partial data loss, and achieves an average MAE of 0.0201 in real-world battery pack applications. This model significantly enhances the accuracy and universality of prediction, enabling accurate prediction of battery SOH under actual engineering conditions.

As one of the major high-speed railway ballastless track structures in China, CRTSIII slab ballastless track has been laid for more than 6500 km. However, there are no detailed studies on its track irregularity deterioration throughout extended service periods, which may threaten the safety and stability of high-speed vehicles (HSV). In this study, a long-term tracking detection of CRTSIII slab ballastless track irregularities has been conducted, revealing its annual evolution law. An HSV-track coupled dynamics model was established to investigate the HSV dynamic responses under annual evolution of track irregularities. Considering the potential deterioration of track irregularities to extremely bad condition, the recommended classified limits for irregularity are proposed by analyzing the limit-exceeding probability of the safety and stability indexes of HSV. The results show that: taking 10 m wavelength as a demarcation, longer-wavelength irregularities exhibit larger amplitudes, faster evolution rates and a linear increasing trend, primarily affecting the stability of HSV. Conversely, shorter-wavelength irregularities exhibit smaller amplitudes and an insignificant evolution trend, predominantly affecting the safety of HSV. Furthermore, the periodic irregularity induced by the arching of 32 m simply-supported beam bridge should be paid closer attention to, as their evolution rate significantly surpasses that of irregularities at other wavelengths.