With the rapid development of electric vehicles and energy storage systems, lithium iron phosphate (LiFePO₄, LFP) batteries are widely used due to their excellent safety, stability, and long cycle life. However, with the extension of usage time, LFP batteries have gradually exposed failure problems in actual use, which not only affect the performance of the battery, but also bring new challenges to the recycling and reuse of the battery. The existing LFP battery regeneration technology can be roughly divided into echelon use, pre-treatment, and chemical regeneration. Pre-treatment includes discharge, disassembly and physical separation, while chemical regeneration includes solid-phase repair, liquid-phase recovery, and direct regeneration. Solid phase and liquid-phase methods have their own advantages in wastewater treatment, thermal energy consumption, recovery process, environmental protection, and progress space. This review aims to summarize the field of recycling and repair of retired lithium iron phosphate batteries, summarize the assessment methods of batteries state of health (SOH) in cascade utilization, explain the physical sorting principles in pretreatment, evaluate common recycling and repair methods and economic benefits, and provide a basis for the future recycling industry. Future research should focus on further exploring process optimization, and the development of recycling and repair technologies should explore more efficient and low-cost recycling processes. With the continuous progress of technology and the increase in market demand, the recycling and reuse of LFP batteries show broad application prospects, promoting the sustainable development of the battery industry.

Carbon fiber is one of the most widely used conductive phases in electrically conductive concrete (EC), yet existing studies lack consistency and systematicity in parameter selection. In this study, the effects of different carbon fiber lengths (3-20 mm) and volume fractions (0.2%-1.8%) on the electrical, mechanical, and electrothermal properties of EC were systematically investigated. Considering practical deicing scenarios, electrical resistivity and electrothermal performance were evaluated under ambient (25 ℃) and low-temperature (-15 ℃) conditions. The results indicate that the resistivity of EC decreases significantly with increasing fiber content, exhibiting a typical percolation effect. When the carbon fiber content reaches 1.2 vol%, the resistivity of EC with different fiber lengths remains consistently below 100 Ω·cm, meeting the requirements for deicing and snow-melting applications. At a fiber length of 8 mm and a content of 1.2 vol%, the flexural and compressive strengths of EC are increased by approximately 79% and 102%, respectively, compared with ordinary concrete. Under a low-voltage (2 V) input, EC demonstrates a rapid temperature rise of about 40 ℃ and maintains stable electrothermal performance at -15 ℃. Considering the combined electrical, mechanical, and electrothermal performance, the optimal mix proportion is identified as 1.2 vol% fiber content with a length of 8-15 mm. These findings provide theoretical and experimental support for the engineering application of carbon fiber EC in cold-region pavement protection and intelligent monitoring.

This study developed a magnetic adsorbent (RM-CS) by modifying red mud (RM) with chitosan (CS), which demonstrated high efficacy in removing heavy metals from wastewater. The surface area of RM-CS increased by 87.3% compared with RM, the average pore size is 9.46 nm, and the thermal stability is high. SEM images revealed that CS wrapped around RM, and it was observed that the material had excellent hydrophobicity. Mechanisms of adsorption of Pb(Ⅱ) by RM-CS include: (i) electrostatic interactions between protonated amino groups and Pb(Ⅱ), (Ⅱ) coordination between hydroxyl groups in Fe/Al/Si oxides and Pb(Ⅱ), and (iii) precipitation reaction between CO^2-₃ and SO^2-₄ with Pb(Ⅱ). In addition, the adsorption process was found to involve physical adsorption and monolayer chemisorption by kinetic and isothermal modeling, and the maximum adsorption amount could reach 205.27 mg/g when the pH value was 6 and the of RM-CS was 1 g/L. At the same time, Zn(Ⅱ) and Cr(Ⅵ) in the solution would compete for the adsorption sites with Pb(Ⅱ), and the competition intensity of Zn(Ⅱ) was about 5.3 times that of Cr(Ⅵ).

Cerium oxide-modified natural rubber (NR/CeO₂) composites were prepared using rare earth cerium oxide (CeO₂) as a rubber antioxidant. The effects of CeO₂ dosage on the mechanical properties, thermal stability, aging resistance, and abrasion resistance of NR/CeO₂ composites were investigated. The results indicate that the tensile strength, elongation at break, and aging resistance of the composites initially increase and then decrease with increasing CeO₂ content. While the CeO₂ content is 1 wt%, the mechanical properties, aging resistance, and abrasion resistance of NR/CeO₂ composites are optimal. Compared with the composites without CeO₂, the tensile strength and elongation at break are increased by 15.4% and 20%, respectively. The heat resistance index of NR/CeO₂ composites is enhanced by 8.2 ℃, and the decomposition temperature is raised by nearly 30 ℃. The smallest abrasion volume of NR/CeO₂ composites reached to 0.2373 cm³.

The performance of silicon carbide/epoxy composites is constrained by interfacial bonding strength and dispersion. This study employed “dopamine+KH550” for surface modification of SiC micropowder. Surface morphology observation and organic group characterization confirmed the formation of a uniform organic layer on the surface, with significantly improved dispersion. Thermogravimetric analysis revealed that the modified composite exhibited a maximum increase of 27 ℃ in T_95% under nitrogen and air atmospheres, demonstrating enhanced thermal stability. Dynamic mechanical analysis revealed that increasing filler content markedly elevated the composite's hardness, energy storage modulus, and glass transition temperature. This enhancement was attributed to the strong chemical bonding between KH550 and the epoxy matrix, coupled with improved stress transfer efficiency. This study validates the effectiveness and necessity of the “PDA+KH550” surface treatment for enhancing the overall performance of SiC/epoxy composites.

Cu-Cr alloys have emerged as critical candidate materials for extreme service conditions—including power transmission, aerospace thermal management systems, and radiation-resistant components in nuclear power plants—due to their unique combination of high electrical conductivity and high strength, coupled with excellent high-temperature oxidation resistance and corrosion resistance. Using CiteSpace bibliometric methods, a quantitative and visual knowledge mapping analysis was conducted on 561 research papers related to copper-chromium alloys in the CNKI database, examining authors, institutions, and keywords. The results reveal that China has developed substantial research depth in this field, with collaborative networks exhibiting “small group clustering” characteristics. Research hotspots primarily focus on heat treatment/plastic deformation processes, mechanical-electrical property synergy optimization, and microstructure-property relationships, with high-strength, high-conductivity performance demonstrating the most significant research value. To resolve the strength-conductivity trade-off, aging heat treatment and microalloying have emerged as primary strategies. When coupled with rapid solidification and severe plastic deformation technologies, these approaches enable cross-scale regulation of nano-precipitates such as Cr and Cu₅Zr. Burst term analysis reveals that recent research frontiers are dominated by tensile strength, upcasting continuous casting, and precipitate phases, with short-process preparation technologies gaining prominence due to their cost-performance advantages. Future studies will pursue “dual-90”(90% IACS conductivity with 900 MPa strength) or higher performance benchmarks to meet demanding applications in aerospace and high-speed rail contact wires.

Cement-based materials remain indispensable as primary building materials in human society, and the structure-function integration has become an important direction for the sustainable development of cement-based materials. Silicon carbide has been widely concerned and applied because of its advantages of high hardness, corrosion resistance, heat stability, high temperature resistance, strong dielectric loss ability and good thermal conductivity. Scholars have introduced silicon carbide into the field of cement-based materials, and have carried out beneficial exploration, finding that silicon carbide modified cement-based materials show the potential as structure-function integration materials. Silicon carbide can be used as a reinforcement component and functional component to improve the mechanical properties, durability, high temperature resistance, electromagnetic shielding properties, wave absorption properties, microwave deicing efficiency and thermal conductivity of cement-based materials. In this paper, the research progress of structural and functional properties of silicon carbide modified cement-based materials at home and abroad is reviewed, and the future development of silicon carbide modified cement-based materials is prospected.

With the increasingly stringent performance requirements for cutting tools, molds, and key moving components in high-end manufacturing, traditional hard coatings such as TiN and TiAlN struggle to meet the application demands under extreme working conditions involving high speed, high temperature, and heavy load. Doping with new elements to further enhance coating performance is an effective strategy. Among these, TiAlCrN quaternary nitride coatings have been extensively studied by researchers worldwide due to their excellent hardness, wear resistance, and oxidation resistance. This paper provides a systematic review of the advantages and disadvantages of preparation processes for TiAlCrN hard coatings, analyzes the influence of coating elemental composition on their microstructure, summarizes various strengthening mechanisms of mechanical properties, elucidates the improvement mechanisms of tribological performance and high-temperature oxidation resistance, and further introduces their current application status in fields such as cutting tools and molds. Finally, potential future research directions and development trends in this field are discussed, aiming to provide theoretical references and technical insights for the further design and optimization of high-performance TiAlCrN coatings.

Esophageal benign stricture has become a common digestive disease with the improvement of public health awareness. The implantation of an esophageal stent remains the main clinical method to relieve obstruction and improve swallowing. In recent years, biodegradable stents have received increasing attention because they can gradually degrade after fulfilling their function and avoid secondary removal. Among them, biodegradable magnesium alloy stents show great potential due to favorable bio-compatibility, controllable degradation, and ion release capacity. To address the rapid corrosion of magnesium alloys in physiological environments, various strategies have been adopted. Alloying has been used to refine micro-structures and improve corrosion resistance. Surface modification methods, such as micro-arc oxidation, polymer coatings, and composite functional layers, have provided protective barriers and enabled controlled ion release. Structural optimization of stents has also been carried out to achieve a better match between mechanical strength, flexibility, and degradation behavior. These approaches have led to significant improvements in corrosion resistance, bio-compatibility, controlled release, and mechanical compatibility. With the development of biomedical materials and tissue engineering, biodegradable magnesium alloy stents have become a research hot spot. Many in vitro and in vivo studies have confirmed their safety and therapeutic potential. However, challenges remain, including precise control of degradation rate, maintenance of mechanical integrity, and reliable evaluation of long-term biological responses. Future research will likely focus on multifunctional coatings, drug delivery systems, and advanced manufacturing technologies to accelerate clinical translation. In conclusion, biodegradable magnesium alloy stents represent a promising direction for the treatment of esophageal benign stricture. Current progress has demonstrated their feasibility, while ongoing research continues to provide insights into their application and future development.

The polyurethane foam thermal insulation materials were prepared by one-step foaming method with glassy beads (GB) as the reinforcing phase. The effects of GB ratio on the macro/micro morphology, hydrophobicity, mechanical properties, thermal insulation properties and flame retardancy of polyurethane foam thermal insulation materials were investigated. The results showed that GB combined with polyurethane foam through the weak interaction of hydrogen bond, and when mixed with polyurethane foam, it could improve the cell structure of foam as heterogeneous nucleating agent. The size distribution of bubbles was more uniform, and the defects of cell wall were reduced. At the same time, the hydrophobicity of polyurethane foam insulation materials were increased, and the contact angle increased from 101.1° of pure polyurethane foam to 124.7° of 20% GB sample. The introduction of GB had improved the mechanical properties of insulation materials. The compressive strength of the 15%GB sample was 342.7 MPa, and the thermal conductivity and density had reached their minimum values of 0.0218 W/(m·K) and 0.0726 kg/m³, respectively, demonstrating the optimal insulation performance. Meanwhile, the 15%GB sample had the best flame retardant performance, with a minimum peak heat release rate (PHRR) of 165.2 kW/m², a minimum total smoke production (TSP) of 1.49 m², and a maximum residual carbon rate of 36.5 wt%. During the vertical flame spread test, the flame spread speed of the 15%GB sample significantly slowed down. At 20 s, the flame slowly reached the top of the sample, and the flame intensity significantly decreased, indicating the best flame retardant performance.

Polyamide 6 (PA6), as an important category of engineering plastics, has been widely applied in various industrial fields including automotive manufacturing, electronic devices, and hydrogen storage systems due to its excellent properties. However, the inherent brittleness of this material significantly limits its application under high-stress conditions, making toughening modification research crucial for expanding its engineering applications. To address this critical issue, this study innovatively designed a ternary synergistic reinforcement system comprising PA6/elastomer/carbon nanofiber (CNF). The research reveals that CNF plays multiple reinforcing roles in the composite system. It acts as a stress-transfer bridge between the elastomer and PA6 matrix, significantly improving interfacial stress transfer efficiency, while also serving as a heterogeneous nucleating agent to refine the PA6 crystalline structure, thereby increasing crack propagation paths to enhance energy dissipation capacity. Notably, the incorporation of CNF not only synergistically improves the impact performance of the material but also effectively compensates for the strength loss induced by the elastomer, achieving a balanced optimization of both strength and toughness. Experimental results demonstrate that the composite system containing 10 wt% elastomer and 1 wt% CNF exhibites an excellent performance balance, with an impact strength of 43.1 kJ/m² (a 215% increase compared to the CNF-free system) while maintaining a tensile strength of 44.7 MPa. This multi-scale CNF-based synergistic reinforcement strategy provides a novel technical approach for developing high-strength and high-toughness PA6-based composites, offering an innovative material design concept for high-performance engineering applications.

This study employed sodiation and calcination processes to synthesize V₂O₅ materials, which were subsequently assembled into CR2032 coin cells as cathodes for lithium-ion batteries. The experiment aimed to investigate the differences in phase structure, micromorphology, and electrochemical performance between V₂O₅ materials with in-situ Na⁺/Ca²⁺ doping (resulting from residual ions during the respective processes) and battery-grade V₂O₅. Results indicate that the in-situ Na⁺/Ca²⁺-doped V₂O₅ possesses a layered structure with a nanosheet-like surface morphology. XRD analysis confirms that the doped samples retain the V₂O₅ phase. XPS results demonstrate the successful incorporation of Na and Ca elements into the V₂O₅ lattice, accompanied by the presence of V⁴⁺ species and oxygen vacancies. Among the samples, the Ca²⁺-doped V₂O₅ (VO-C) exhibits the most superior overall electrochemical performance. It delivers a high initial discharge specific capacity of 341 mAh/g and demonstrates the best rate capability. Furthermore, after 200 cycles at a 5 C rate, it maintains a discharge capacity of 138 mAh/g, corresponding to an impressive capacity retention of 80.70%.

In this paper, MOF-derived TiO₂/C composites were prepared by calcination under argon atmosphere using MIL-125(Ti) as a precursor, which successfully retained the porous carbon skeleton (specific surface area of 192.14 m²/g) and formed the Ti—O—C interfacial bonds (XPS showed C—O peak shifted by 0.3-0.5 eV) and oxygen vacancies (O 1s 531.46 eV defect peak in O 1s). The synergistic effect of the carbon skeleton and oxygen vacancies narrowed the band gap to 3.01 eV, which significantly broadened the photoresponse range. Photoelectronic tests showed enhanced carrier separation efficiency (photocurrent density of 24.74 μA/cm², a 40% increase over P25) and reduced charge transfer resistance. In photocatalytic CO₂ reduction, the material achieved a CO yield of 434.12 μmol/(g·h) (12-fold enhancement over P25) and selectively favored the CO pathway (96.09 μmol/(g·h) yield of CH₄). The mechanism study shows that the heterojunction of anatase/rutile mixed phase drives electron migration, the Ti—O—C bond mediates charge transfer to enrich the carbon skeleton with electrons to activate CO₂, and the oxygen vacancies inhibit carrier complexation and optimize the reaction pathway, which synergistically form the synergistic mechanism of “carbon skeleton-oxygen vacancies-Ti—O—C”, and provide a new paradigm for the design of high-efficiency MOF-derived photocatalysts.

Four composite aerogel catalysts, Co₃O₄@SiO₂, Co₃O₄@ZrO₂, Co₃O₄@Al₂O₃ and Co₃O₄@TiO₂, were prepared using the sol-gel method, and their performance in activating peroxymonosulphate (PMS) to degrade ofloxacin (OFL) was investigated. Through performance testing and various characterization methods, four composite catalysts were compared, and the optimal catalyst Co₃O₄@SiO₂ was selected. A systematic study was conducted on its reaction mechanism and influencing factors. The results showed that the Co₃O₄@SiO₂/PMS system achieved a degradation efficiency of 99.14% for 10 mg/L OFL within 10 min, and could efficiently degrade OFL within a pH range of 3-11. The degradation reaction followed first-order pseudo-kinetic behaviour. Paramagnetic electron spin resonance spectroscopy and quenching experiments confirmed that SO^-·₄ and ¹O₂ were the primary active species in the reaction. TOC and cycling experiments demonstrated the high performance and recyclability of Co₃O₄@SiO₂, providing an efficient catalyst for the degradation of antibiotic wastewater.

To address the limited adsorption capacity of raw biochar for tetracycline (TC) and the drawback that magnetically recoverable iron-doped biochar often requires high-temperature treatment at 700 ℃, this study used urea and FeCl₃·H₂O as nitrogen (N) and iron (Fe) sources, respectively. N-Fe co-doped biochar was first prepared via low-temperature carbonization at 300 ℃, followed by magnetization. This strategy successfully produced N-Fe co-doped biochar (1.5Fe-NPC⁺) with excellent tetracycline adsorption performance. Characterization results showed that the specific surface area and TC adsorption capacity of 1.5Fe-NPC⁺ increased by 6.8 times and 9.56 times, respectively, compared with raw biochar. Thermodynamic and kinetic fitting results indicated that the adsorption involved both physical and chemical interactions. π-π stacking, pore filling, hydrogen bonding, and electrostatic interactions were identified as the main mechanisms driving TC adsorption by 1.5Fe-NPC⁺.

Postoperative bacterial infection and insufficient osseointegration are primary causes of titanium implant failure. Based on this, we employed micro-arc oxidation technology to in situ generate a porous TiO₂ coating on the titanium (Ti) surface. This coating was further loaded with mesoporous polydopamine (MPDA) to enhance near-infrared (NIR) photothermal conversion efficiency. Subsequently, L-arginine (L-Arg) and indocyanine green (ICG) were sequentially loaded onto the coating to realize a NIR-responsive synergistic antibacterial function. The microstructural morphology and chemical composition of the composite coating were characterized using field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), and Fourier-transform infrared spectroscopy (FT-IR), confirming the successful fabrication of the TiO₂@MPDA/L-Arg/ICG composite coating (TiO₂@IA-MPDA). Under 808 nm NIR irradiation, the introduction of MPDA significantly enhances the photothermal conversion efficiency of the TiO₂ coating. Antibacterial testing results indicate that the incorporation of MPDA can substantially improve the bactericidal efficacy of the coating. Notably, the synergistic antimicrobial activity of L-arginine (L-Arg) and indocyanine green (ICG) under NIR exposure results in a maximum bacterial eradication rate of 96% against Staphylococcus aureus. This study provides a new approach for the development of NIR-responsive composite antibacterial coatings on titanium implant surfaces.

Surface treatment of expanded polystyrene (EPS) particles was carried out using NaOH, and the surface treated EPS particles were used as reinforcing phases to prepare EPS concrete. The effects of different NaOH concentrations on the surface morphology, hydrophilicity, and functional groups of EPS particles were systematically studied, and the microstructure, thermal insulation, mechanical properties, and frost resistance of EPS concrete samples treated with NaOH surface were investigated. The results showed that after NaOH treatment, hydroxyl and other oxygen-containing functional groups were introduced on the surface of EPS particles, making the surface of EPS particles rougher and improving hydrophilicity. The 3%EPS-NaOH sample had the best comprehensive performance, with the lowest proportion of macropores being 3.11%, the lowest proportion of micropores being 19.28%,the highest proportion of micropores being 60.44%, and the highest degree of pore morphology integrity. Its compressive strength and flexural strength reached their maximum values of 2.20 and 0.38 MPa, respectively. The lowest shrinkage rate was 4.52 mm/m at 90 d, and its minimum thermal conductivity was 0.06 W/(m·K). After 120 freeze-thaw cycles, its quality loss rate and strength loss rate were the lowest, 7.01% and 5.54%, respectively.

The exponential growth of industrial operations has exacerbated organic dye effluent pollution to critical levels, mandating the development of high-efficiency treatment technologies as a fundamental research priority in environmental engineering. In this study, magnesium-modified graphene composites were prepared via a physical mixing method, and their microstructure and chemical composition were systematically characterized using XRD, SEM, and FT-IR techniques. Experimental results demonstrated that the composite material with an optimal MgO to graphene mass ratio of 2∶1 exhibited superior adsorption performance for Rhodamine B (RhB) and methylene blue (MB), achieving maximum adsorption capacities of 184 mg/g and 192 mg/g, respectively, with removal efficiencies exceeding 90%. The material maintained stable adsorption performance across a wide pH range and under various coexisting ion conditions. Isothermal adsorption modeling indicated a monolayer adsorption mechanism, while kinetic analysis revealed that the pseudo-second-order model better described the adsorption process, suggesting chemisorption as the dominant mechanism. The adsorption mechanism predominantly involves synergistic hydrogen bonding, π-π stacking interactions, and chemical coordination bonding. After five consecutive adsorption-desorption cycles, the composite retained high adsorption capacities of 174.2 mg/g for RhB and 162.2 mg/g for MB. This work provides novel material solutions and theoretical foundations for efficient organic dye wastewater treatment, offering significant implications for advancing environmental remediation materials.

Graphitic carbon nitride (g-C₃N₄) has attracted much attentions in the field of photocatalysis due to its advantages, such as high chemical stability and moderate light absorption range. The g-C₃N₄ prepared by the conventional thermal polymerization method is usually in a bulk structure with dense interlayer stacking and a low specific surface area, resulting in relatively low photocatalytic activity. To enhance the photocatalytic activity of g-C₃N₄, bulk g-C₃N₄ was chemically exfoliated using sulfuric acid in this paper. By controlling the exfoliation time, g-C₃N₄ nanosheets with large specific surface area and high photocatalytic activity were successfully achieved. The analysis results of XRD, XPS and FT-IR show that sulfuric acid can destroy the interlayer van der Waals force of g-C₃N₄ through the combined protonation and oxidation etching effect, resulting in a decrease in interlayer spacing and an increase in the surface amino density. The specific surface area of g-C₃N₄ nanosheets obtained after stripping with sulfuric acid for 4 h was the largest of 128.02 m²/g, which was 8 times that of the bulk sample before stripping. Photocatalytic tests demonstrated that the photodegradation rate of methylene blue (MB, 10 mg/L) by this sample was 78.05% after 120 min of visible light (λ ≥ 420 nm) irradiation, which was more than twice that of the sample before delamination (36.42%), indicating that sulfuric acid delamination effectively enhanced the photocatalytic performance of g-C₃N₄.

CA-HD/UF microcapsules were prepared by in-situ polymerization using urea formaldehyde resin (UF) as the shell material and caprylic acid-hexadecanol (CA-HD) as the core material. The effects of emulsifier type, emulsifier dosage, and core to shell ratio on microcapsule preparation were studied. Based on the optimal preparation conditions, CA-HD/UF/CNT microcapsules were prepared by adding carbon nanotubes (CNT) as a high thermal conductivity material. The morphology, thermal conductivity, phase transition characteristics, chemical composition, leakage, and thermal stability of the microcapsules were studied using biomicroscope, scanning electron microscopy, thermal conductivity analyzer, differential scanning calorimeter, infrared spectrometer, and thermogravimetric analyzer. The testing results showed that the CA-HD/UF microcapsules prepared under the conditions of using styrene maleic anhydride copolymer-sodium dodecyl benzene sulfonate (SMA-SDBS) complex emulsifier (m_SMA∶m_SDBS=1∶2), emulsifier dosage of 3.0 wt%, and core to shell ratio of 2∶1 had good morphology, with an average particle size of 3.5 μm, phase transition temperature of 10.07 ℃ and phase transition latent heat of 111.35 J/g, respectively. The encapsulation rate of microcapsules reached 70.11%. When the CNT addition amount was 2.5 wt%, the thermal conductivity of CA-HD/UF/CNT microcapsules were 0.22 W/(m·K), increased by 46.7% compared to the phase change microcapsules without CNT. The encapsulation rate of microcapsules with CNT is 69.53%. There was no chemical reaction between the microcapsule core material and the shell material, nor between CNT and the shell material. The microcapsules after heat treatment had no leakage and good leak resistance. The testing of freeze/thaw cycles and thermogravimetric analysis show that the microcapsules have good heat resistance and stability, and are suitable for cold energy storage.

Bismuth ferrite (BiFeO₃, BFO) is a significant room-temperature single-phase multiferroic material, demonstrating considerable potential for low-power spintronic devices. However, its extremely week magnetism severely hinders the pratical development of multiferroic applications. Employing rare-earth (RE) ion substitution to tailor the magnetic properties of BFO, this study successfully synthesized Bi_0.8RE_0.2FeO₃ (RE = La³⁺, Nd³⁺, Ho³⁺) bulk ceramics via the conventional solid-state reaction method. The phase structure, local structure, and surface microstructure of the samples were systematically characterized using X-ray diffraction (XRD), Raman spectroscopy, and scanning electron microscopy (SEM). Results indicate that all samples crystallize in the perovskite structure. The BFO ceramic exhibits a typical rhombohedral phase with significant impurity phases, whereas RE-doping ceramics markedly suppresses these impurities. The ceramic with moderate La³⁺ doping maintains the rhombohedral structure of BFO, while Nd³⁺ and Ho³⁺ doping samples induce a sturcture transition from the rhombohral to orthorhombic phase. RE ion substitution enhances the densification of the ceramics and modifies the average grain size. Vibrating sample magnetometry (VSM) measurements reveal a linear relationship between magnetization and the applied magnetic field for pure BFO. In contrast, RE-doped ceramics exhibits significant improved magnetic properties. Both Nd³⁺ and Ho³⁺-doped samples display distinct magnetic hysteresis loops, while the La³⁺-doped sample exhibits soft magnetic characteristic. The maximum magnetization of La³⁺-doped BFO reaches 5.75 Am²/kg, representing a 16-fold enhancement compared to undoped BFO (0.359 Am²/kg). This substantial improvement is attributed to lattice distortion-induced octahedral tilting, alterations in the Fe³⁺-O^2--Fe³⁺ bond angle, and the disruption of the space-modulated cycloid spin structure. This work elucidates the role of RE ions in modulating the structure and magnetism of BFO, providing novel doping strategies and theoretical foundations for designing high-performance multiferroic devices.

Using microwave plasma chemical vapor deposition (MPCVD) technology, diamond-graphene composite membrane substrate is grown while simultaneously loaded the active electrocatalytic components of metal Ni, and integrally metal-loaded composite catalyst based on diamond-graphene film (UNCD-MLG/Ni) with three-dimensional porous microstructure is successfully prepared, which provides a new technical approach for the fabrication of three-dimensional porous carbon substrate materials with stable structures and the overall controllable loading of active catalytic metals. In UNCD-MLG/Ni, the nano-diamond forms a lamellar core, while graphene coats the surface in the form of a shell, which constitute a microstructure with abundant pores by vertically disordered alternating to form it. Additionally, metallic Ni is uniformly loaded throughout the substrate material, with a loading amount reaching 2.02 at%. For the oxygen evolution reaction (OER) test, under a current density of 10 mA/cm², the overpotential of UNCD-MLG/Ni is only 329 mV, whereas 467 mV for UNCD-MLG. Meanwhile, the double-layer capacitance (Cdl) of UNCD-MLG/Ni reaches 77.59 mF/cm², much higher than that of UNCD-MLG (21.49 mF/cm²), which indicates that the metal-loaded components form effective active sites, thereby significantly improving the catalytic performance of the material. Moreover, the material can operate stably in an alkaline aqueous solution for 20 h, demonstrating excellent durability brought by the overall loading of active metal components.

To systematically investigate the influence of steel slag fine aggregate on the fracture performance of concrete, this study conducted wedge splitting tests combined with finite element-based inverse analysis. The post-cracking softening behavior of concrete incorporating different steel slag replacement ratios (0%, 10%, 20%, and 30%) was analyzed, and key fracture parameters including crack initiation toughness, fracture energy, and characteristic length were obtained using a tri-linear constitutive model. The results show that the inclusion of steel slag fine aggregate can optimize crack propagation paths, enhance post-peak energy dissipation capacity, and improve the overall fracture toughness of concrete. Fracture energy exhibited an increasing trend with higher slag content. Compared with experimental curves, the fracture energy calculated by the tri-linear model maintained an error within ±10%, demonstrating higher accuracy than the traditional bi-linear model. Although discrepancies were observed between experimental and simulated characteristic lengths, both results confirmed that an appropriate slag content (approximately 20%) significantly improves the crack resistance and toughness of concrete. These findings provide a scientific basis for the practical application of steel slag concrete in structural engineering.

The rapid heat release during hydration and high production costs of ferroaluminate cement limit its application in civil engineering construction. In this study, the effects of steel slag (SS) and GGBS as supplementary cementitious materials on the hydration characteristics and sulfate attack resistance of ferroaluminate cement are investigated. By analyzing changes in fluidity, setting time, compressive strength, hydration heat, hydration products, and sulfate resistance in composite cement systems, the hydration mechanism of steel slag-GGBS- ferroaluminate cement is explored. Results indicate that incorporating steel slag and GGBS initially prolongs and subsequently shortens the setting time, reduces fluidity, and decreases early compressive strength. However, compressive strength continuously increases within 180 d, whereas the control sample exhibits strength retrogression. The addition of steel slag and GGBS promotes the strätlingite, enhancing sulfate resistance. The coefficients of sulfate corrosion resistance of the cement are not less than 1.05 at 28 d, 90 d and 180 d.

Silicon-based ceramic shells doped with B₂O₃ and Al₂O₃ were prepared by stereolithography technology. The addition of B₂O₃ promoted the phase transformation of fused quartz to precipitate cristobalite, thereby reducing the sintering temperature. SEM results showed that the addition of B₂O₃ led to the formation of a liquid phase inside the ceramic, which filled the internal pores and made the microstructure denser. The flexural strength first increased and then decreased, with the maximum reaching 13.31 MPa, indicating that B₂O₃ had a significant improvement effect on the mechanical properties of the ceramic shell. However, excessive B₂O₃ accelerated the generation of cracks, resulting in a decrease in mechanical properties. After determining the optimal B₂O₃ doping amount of 6 wt%, Al₂O₃ was further added to the ceramic shell, which increased the apparent porosity of the ceramic shell, reduced the shrinkage rate, and improved the sintering stability of the shell. The ceramic shell with an appropriate amount of Al₂O₃ still had mechanical properties (11.508 MPa) that meet the requirements of shell casting, which is beneficial to shell casting. Excessive Al₂O₃ significantly reduced the precipitated cristobalite, and the loose microstructure caused a significant decrease in mechanical properties. The test casting experiment on the shell showed that the impeller blades cast with Al₂O₃ doping had better integrity and surface quality. In conclusion, this study improves the comprehensive performance of the ceramic shell by co-doping B₂O₃ and Al₂O₃, and successfully casts impeller blades, which has certain application value in shell casting.

To address the poor mechanical performance of coal-gangue asphalt mixtures, this study incorporates basalt fibers and employs macromechanical testing together with microscopic morphology analysis to investigate how fiber content and length affect pavement performance, and to elucidate the microstructural features and reinforcement mechanism. The results show that when the basalt fiber content is approximately 0.4% and the fiber length is 6 mm, dynamic stability increases by 35.44%, residual stability after water immersion rises by 10.59%, the freeze-thaw splitting tensile strength ratio (TSR) increases by 16.84%, and the maximum flexural tensile strain increases by 23.24%. Microscopic observations indicate that the three-dimensional network formed by the fibers can arrest crack propagation. Moreover, the fibers exhibit good interfacial adhesion with the asphalt binder, enhance aggregate interlock, and improve structural stability. Overall, although coal gangue underperforms natural crushed stone in several indices, the addition of basalt fibers enables the mixture to meet specification requirements for asphalt mixtures. Basalt fibers effectively improve the mechanical properties of coal-gangue asphalt mixtures, providing a theoretical basis and technical support for the broader application of coal gangue in road engineering.

In the screw-extruded 3D printing (fused granulate fabrication, FGF) of fiber-reinforced thermoplastic composites, the mechanical anisotropy caused by the directional alignment of fibers along the flow direction severely restricts their application in multi-axial load scenarios and becomes a core bottleneck for the further development of FGF technology. This study optimized the parameters of screw shear elements through fluid simulation, actively regulated fiber orientation using shear force, screened out the optimal scheme, and verified it through printing experiments. The results show that, compared with conventional screws (CS) which cause fibers to align unidirectionally along the flow direction, shearing screws (SS) successfully induce carbon fibers to form a spatial helical orientation. This significantly reduces the tensile strength difference between two mutually perpendicular printing directions compared with conventional screws, remarkably decreases anisotropy, and simultaneously improves tensile strength. This technology breaks through the direction-dependent limitation of 3D printed composites and provides important technical support for their wide application in high-end manufacturing fields such as aerospace and automotive industries.