To solve the problems of high thermal conductivity and poor insulation performance of traditional inorganic insulation mortar, this paper develops a new type of inorganic insulation mortar with low thermal conductivity by using lightweight aggregates and combining foaming technology. The influence of polystyrene foam particle (EPS) gradation (0.5–0.8 mm, 1–2 mm and 2–3 mm) on the compressive strength, bonding strength, volume water absorption, drying shrinkage, softening coefficient, thermal conductivity, hydration and microstructure (XRD, NMR, CT) of SiO₂ aerogel insulation mortar based on microbial foaming was studied by using ternary phase diagram method. The results show that: (1) The decrease in the amount of small particle EPS resulted in an increase of 3.8% to 52.7% in the thermal conductivity of the insulation mortar specimens. When the content of small particle size EPS is fixed, the thermal conductivity of the insulation mortar specimens decreases by 17.8% to 26.4% as the content of medium particle size EPS increases and the content of large particle size EPS decreases synchronously; (2) The reduction of small particle size EPS content and the increase of medium and large particle size EPS content have an improving effect on the compressive strength and bond strength of insulation mortar, increasing by 12.0%–64.5% and 11.3%–59.1%, respectively; (3) The reduction of small particle size EPS content and the increase of medium and large particle size EPS content increased the volumetric water absorption rate (60.5%–130.0%), drying shrinkage rate (20.0%–160.0%), and softening coefficient (2.7%–8.0%) of the insulation mortar; (4) Changing the aggregate grading did not result in the formation of new hydrate phases in the insulation mortar, but only altered the slurry content of the insulation mortar specimens. Microscopic analysis shows that under various aggregate gradations, the pores of insulation mortar are mainly concentrated in capillary pores, and the EPS ratio of each particle size is 6:2:2, forming the most tightly packed group, which is the optimal aggregate gradation; (5) From the perspective of insulation performance, the optimal grading of EPS is 6:2:2. At this time, the thermal conductivity of the insulation mortar is 0.031 3 W/(m·K), the compressive strength is 102.5 kPa, the bonding strength is 156.8 kPa, the volumetric water absorption rate is 4.3%, the drying shrinkage rate is 0.5%, and the softening coefficient is 0.75.

Through the full wet leaching of multiple components in vanadium tailings using oxalic acid solution, the influences of oxalic acid concentration, leaching time, leaching temperature, and water-to-ore ratio on the leaching rates of valuable elements were examined. The results indicated that under the conditions of a leaching temperature of 150 °C, an oxalic acid concentration of 20%, a reaction duration of 150 min, and a water-to-ore ratio of 10:1, the one-step leaching rates of iron, vanadium, and titanium exceeded 99%. Moreover, the asynchronous extraction of vanadium and titanium resources at temperatures of 160 and 180 °C was realized. This verified the feasibility of the asynchronous extraction process for multiple valuable components from vanadium tailings, providing data support for the clean recycling and utilization of vanadium tailings.

Iron-chromium redox flow batteries (ICRFBs) are among the most cost-effective large-scale energy storage systems owing to their low price, flexible design, and long service life. To further enhance the electrochemical performance and reduce the raw material cost of advanced graphite felt electrodes. Common commercial graphite felt (GF) was used as the basic electrode material, and inexpensive and reliable biomass materials (rice straw, wood chips, and corncobs) were used as raw materials for carbon-based catalysts. Advanced electrodes were fabricated from biomass carbon materials of rice straw, wood chips, and corncobs through pretreatment, sintering, and pyrolysis. Notably, the advanced graphite felt electrode prepared from corncobs biomass carbon material (YM-TGF) has a larger specific surface area, abundant active functional groups, and a faster charge transfer rate. When the current density was 60 mA/cm², the ICRFB assembled with the advanced electrode activated by YM-TGF achieved a charging capacity of 24.78 Ah/L, and the capacity decay rate was only 0.08% per cycle after 500 charge-discharge cycles.

The performance of plant-mixed hot recycled asphalt mixtures with high reclaimed asphalt pavement (RAP) content is often compromised by instability and degradation due to insufficient interfacial fusion between aged asphalt and ordinary rejuvenators. To address this challenge, we proposesd a novel high-permeability rejuvenator designed to enhance the compatibility of aged asphalt while maintaining the mechanics and road performance of recycled mixtures. A systematic experimental framework was developed and implemented to evaluate the road performance of high RAP content recycled asphalt mixtures. The rejuvenation efficacy of fully integrated aged asphalt was assessd by theological tests. Aluminum tube permeability experiments were conducted to quantitatively investigate the permeability effect of the high-permeability rejuvenator. The road performance of high-dosage (60%–80%) recycled asphalt mixtures prepared with the high-permeability rejuvenator is validated through comprehensive testing and evaluation.

Portland cement adhesives serve as critical components in ultra-high voltage large tonnage insulators, significantly playing a vital role in the safety and stability of transmission line operation. This work systematically investigates the performance of Portland cement adhesives by controlling three key factors: cement-to-sand ratio, defoamer dosage and curing method with the aim of designing high-performance formulations suitable for ultra-high voltage transmission projects. It was found that with a cement-to-sand ratio of 2:1, the flexural and compressive strengths at 11 days reached 15.3 and 115.0 MPa respectively, and 28-day drying shrinkage rate was only 0.030%. The addition of defoamers promoted the formation of a denser structure, which significantly enhanced both mechanical properties and drying shrinkage characteristics. Under standard curing conditions, early-stage formation of AFt filled internal pores, cutting porosity by 1.85% compared with air-cured specimens and further mitigating shrinkage. Glass insulators bonded with the optimized adhesive satisfied the mechanical and thermomechanical requirements for ultra-high voltage heavy tonnage applications, as confirmed by corresponding performance tests.

This study investigated the optimization of gradation and performance of cement-stabilized materials incorporating recycled brick-concrete aggregates (RBCA) with various replacement ratios of recycled brick aggregate (RBA). A gradation structure, referred to as the refined-dense (RED) gradation, was developed using discrete element method simulations and a multi-step blending strategy to minimize packing porosity. In addition, two conventional gradation types, namely skeleton-dense (SKD) and suspension-dense (SUD), were included for comparison. The optimized RED gradation reduced the porosity to 3.15%, indicating enhanced aggregate packing and structural compactness. Mechanical performance was evaluated through unconfined compressive strength and splitting tensile strength tests. At 30% RBA replacement ratio, the RED gradation reached 3.69 MPa in 28-day UCS, which was 3.6% and 27.2% higher than the SKD and SUD gradations, respectively. In tensile tests, the RED gradation consistently delivered superior performance, achieving a 28-day tensile strength of 0.88 MPa at 0% replacement, which was 15.8% and 20.5% higher than SKD and SUD. Recyclability was confirmed by acceptable crushing value and flakiness index of second-generation recycled aggregates from RED specimens across all RBA replacement levels. Even at a 30% RBA replacement ratio, the second-generation recycled aggregates still met the Class II specifications for subbases of secondary and lower-grade highways. At RBA replacement levels up to 16%, the second-generation recycled aggregates met Class II standards for subbases of expressways and primary highways. When the replacement ratio increased to 24%, they still satisfied Class I standards applicable to subbases of secondary and lower-grade highways.

To investigate the effects of wet carbonation on the composition of steel slag and the relationship between its carbonation degree and hydration reactivity, this study systematically compares steel slag with low carbonation (1 hour of carbonation) and high carbonation (4 hours of carbonation), focusing on their impact on the hydration process and mechanical properties of cement-based composites. Carbonated steel slag contains a significant amount of calcium carbonate, dicalcium silicate and silica gel, exhibiting excellent cementitious activity and micro-aggregate effects, making it a high-quality supplementary cementitious material for cement-based products. The results indicate that wet carbonation leads to the formation of calcite-type calcium carbonate and silica gel in the steel slag. These components accelerate the generation of hydration products, increase the specific surface area of the slag, and alter its hydration reactivity and pozzolanic activity. Tests showed that when 10% of this carbonated of 1 h steel slag powder was incorporated into cement paste, the 3-day and 28-day compressive strengths reached 25.4 and 42.4 MPa, respectively, demonstrating a significant improvement compared to the non-carbonated steel slag group. Excessive carbonation reduces the early strength (3 days) of cement mortar with high steel slag content. In contrast, steel slag with a low degree of carbonation enhances the later strength (28 days) of the mortar, with this improvement being particularly pronounced at low incorporation levels. Its excellent micro-aggregate filling effect and nucleation action synergistically promote the hydration process, further optimizing the pore structure of the hardened paste. Meanwhile, the introduction of carbonated steel slag effectively regulates the morphology and distribution of hydration products, enhancing the compactness of the interfacial transition zone. XRD and SEM analyses reveal that C-S-H gels and calcium carbonate whiskers interweave to form a dense network structure, significantly improving the integrity of the matrix.

This study investigates the deterioration mechanisms of reinforced concrete incorporating mineral admixtures under combined carbonation and salt erosion. Non-destructive electrochemical techniques were employed to monitor the durability degradation process, evaluated through carbonation depth, relative dynamic elastic modulus, and electrochemical parameters including polarization curves, corrosion current density, and electrochemical impedance spectroscopy. Microscopic analyses via X-ray diffraction (XRD) and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) were utilized to elucidate the underlying deterioration mechanisms. A stochastic Wiener process-based reliability model was developed to predict the service life of reinforced concrete under different exposure conditions. The results showed that the control group exhibited the highest carbonation resistance, followed by the fly ash (FA)+ground granulated blast-furnace slag (GGBS)+silica fume (SF) group, while the FA group and the FA+GGBS group demonstrated the lowest resistance. In the carbonation-chloride environment, the corrosion current density of the FA+GGBS group exceeded 1.0 µA·cm⁻² after 120 d, indicating a high corrosion level. In the carbonation-composite salt environment, all groups except the control reached a high corrosion level within 120 days. The durability degradation of all four concrete types in both environments conformed to the stochastic Wiener process. The predicted service lives in the carbonation-chloride environment were 1 710, 1 570, 701, and 2 210 d for the control, FA, FA+GGBS, and FA+GGBS+SF systems, respectively. In the carbonation-composite salt environment, the corresponding service lives were 1 180, 747, 633, and 755 d.

This study systematically investigated the effects of dispersion methods (hand stirring (HS), mechanical stirring for 5 min (MS5), and ultrasonication for 10, 15, and 20 min (UL10, 15, 20) and polycarboxylate superplasticizer (PCE) dosage on the dispersion quality and stability of graphene oxide (GO) suspensions using UV-vis spectroscopy, LF-NMR, and visual analysis. GO-polymer modified cement mortar (GOPMC) was prepared and FTIR, XRD, LF-NMR, SEM were used to assess the fluidity, mechanical strength, phase composition, pore structure and microscopic morphology of GOMPC. Results indicate that UL15 combined with GO:PCE=1:2, achieves peak dispersion stability. Although well-dispersed GO slightly reduced GOMPC fluidity, ethylene-vinyl acetate (EVA) can significantly improve the fluidity. Synergistically, optimized GO and EVA enhanced 28 d compressive and flexural strength, primarily due to stimulated hydrate nucleation, refined porosity and microstructure.

The freeze-thaw damage degree of shotcrete in the initial support of tunnels in cold regions is significantly higher than that of casting concrete in the secondary lining structure, but the mechanism is still unclear. The freeze-thaw damage process of shotcrete and casting concrete was comparatively studied in this paper. The mechanism of the influence of molding method on the freeze-thaw failure process was also analyzed. The results show that: the deterioration rate of shotcrete under freeze-thaw cycles was significantly faster than that of casting concrete. Under the same number of freeze-thaw cycles, the surface spalling, mess loss, and decline in compressive strength and dynamic elastic modulus for shotcrete was more serious than that for the casting concrete. The changes in the pore structure of shotcrete caused by the spraying process are the fundamental reason for the poor frost resistance of shotcrete. During the freezing process (−15 °C), almost all pores greater than 1 µm freeze and with a size in the range of 0.005–1 µm partially freeze. As the higher content and larger pores in shotcrete, more new pores will be formed during the freeze-thaw process. Additionally, as the high porosity of interfacial transition zone (ITZ) and matrix in shotcrete, the freeze-thaw failure process of shotcrete is characterized by the failure of ITZ first, followed by the matrix. However, the casting concrete mainly exhibits ITZ damage within 75 freeze-thaw cycles.

This study systematically investigates the influence of rubber particle content and water-cement ratio on the performance of cement mortar. Through rheological testing, mechanical property evaluation, and microstructural characterization using scanning electron microscopy (SEM) and X-ray computed tomography (X-CT), it was found that at a 5% volumetric replacement of rubber particles, the mortar maintains favorable workability, with 28-day compressive, flexural, and tensile strengths increased by 5.6%, 7.7%, and 26.1%, respectively, relative to the control group. However, excessive incorporation (>10%) results in a 121% increase in initial yield stress and a 43% rise in viscosity, accompanied by interfacial debonding and elevated porosity, leading to a significant deterioration in mechanical performance. Microstructural analysis confirms that enhanced surface hydrophilicity of modified rubber particles improves the interfacial transition zone (ITZ) structure, thereby enhancing material toughness. This study highlights the critical role of rubber-cement interface optimization in the toughening mechanism of cementitious composites, providing a theoretical foundation for practical engineering applications.

Magnesium oxychloride cement (MOC) holds distinct advantages over ordinary cement in terms of resource consumption and carbon emissions. However, its poor water resistance has consistently hindered the widespread application of this material. We selected citric acid (CA) and phytic acid (PA) as admixtures added to MOC. We evaluated their effects on the setting time, compressive strength, and water resistance of MOC. Results indicate that the incorporation of citric acid and phytic acid significantly retards the setting of MOC while reducing its compressive strength, particularly in the early stages. However, both additives effectively enhance MOC’s water resistance. Compared to MOC containing either phytic acid or citric acid alone, the MOC-CA-PA composite achieved a high water resistance coefficient (0.87). SEM, XRD, and XPS analysis of the MOC-CA-PA composite revealed that citric acid and phytic acid provide additional active sites for Mg²⁺ in MOC, and MOC formed a stable double-chelation network. This enhances the stability of the 5-phase and unreacted MgO particles in MOC under humid conditions, further improving its water resistance. This provides further insights for composite additives to enhance the water resistance of MOC.

This study investigated the macroscopic performance of two types of concrete for a bridge (C40 and C60) under horizontal pumping at high altitude area by evaluating the slump, slump flow, compressive/splitting tensile strength, early shrinkage and crack resistance. The microscopic mechanisms were elucidated through XRD, MIP, TG-DSC, and SEM analysis. The findings revealed that increasing the pumping distance results in decreasing the slump and slump flow. At 164 m pumping distance, the C40 and C60 showed 17.9% and 16.7% reduction in slump, and 7.7% and 8.0% reduction in slump flow. At the same pumping distance, the 28 d compressive strength increases by 8.8% and 6.3% for C40 and C60, while the 28 d splitting tensile strength increases by 32.4% and 29.3%, respectively. Unfortunately, the early shrinkage and cracking of the concrete becomes more severe. At 164 m pumping distance, the C40 and C60 experiences 30.0% and 28.9% increase of shrinkage and the total crack area per unit area expands by 4.0 times and 8.2 times, respectively. In addition, the horizontal pumping behavior does not change the compositions of the concrete and the morphology of the hydration products, but improves the degree of the cement hydration and reduced the porosity of the concrete.

This study aims to improve the performance of alkali-activated slag recycled mortars (AASRMs) by incorporating pre-wetted recycled fine aggregates (RFAs). RFAs with various substitution rates (50 wt% and 100 wt%) and humidity states including air-dried (AD) and saturated surface-dried (SSD) were used to investigate the workability, mechanical properties, drying shrinkage, and micro-morphology of AASRMs. Moreover, life-cycle cost (LCC) and environmental impacts of AASRMs during the raw materials and production phases were comprehensively evaluated. The results showed that, with the increase in RFA contents, the workability, mechanical properties, and drying shrinkage of AASRM deteriorated. However, pre-wetted RFAs significantly enhanced mechanical properties and dry shrinkage resistance of AASRCs. Compared to mortar with 50 wt% AD-RFAs, the specimen with 50 wt% SSD-RFAs exhibited 23.8% higher 14-day compressive strength, 17.6% greater 14-day flexural strength, and 9.7% lower 14-day drying shrinkage. Microstructural analysis revealed that pre-wetted RFAs provided an internal curing effect, promoting hydration and improving the interfacial transition zone between the RFA and the matrix. In addition, the incorporation of RFA led to a reduction in LCC, while a slight increase in environmental performance across all impact categories for AASRMs. This study provides an effective method to improve the mechanical performance and shrinkage resistance of AASRMs, facilitating their practical application.

This study systematically investigated the effects of retarder type, dosage, and material temperature on the properties of magnesium phosphate cement (MPC). The results demonstrated that the setting time of MPC decreased with increasing material temperature but increased with the addition of retarders. At moderate material temperature, the setting time initially increased and then decreased with increasing H₃BO₃ dosage. The MgCl₂ retarder exhibited a stronger retarding effect than CaCl₂, but was still less effective than Na₂B₄O₇·10H₂O. MgCl₂ was identified as the most effective single retarder. MPC incorporating Na₂B₄O₇·10H₂O, MgCl₂, and Na₂HPO₄·12H₂O exhibited a denser microstructure, longer setting time and enhanced mechanical strength. The compound retarder comprising H₃BO₃ + MgCl₂ + Na₂HPO₄·12H₂O was identified as the most effective among all tested single and compound retarders. A higher rate of pH increase corresponded to a shorter initial setting time. This study developes novel retarders for MPC and provides a foundation for further research.

To investigate the interfacial bond performance of highland barley straw ash (HBSA)-modified magnesium oxychloride cement mortar (MOCM) with ordinary concrete, the influence of three variables, HBSA dosage, interfacial agent, and thickness of MOCM, on the interfacial bond strength in five environments, namely, indoor environment, immersion, salt brine, freezing and thawing, and salt-freezing coupling, was analyzed. A hybrid GA-SVR model was developed through genetic algorithm optimization of support vector regression. The inputs of the prediction model were erosion environment, erosion age, interfacial agent, HBSA dosage, and MOCM thickness, and the output was interfacial bond strength. The 1 960 sets of experimental data were utilized as the database for the hybrid prediction model, including 1 372 sets of data (70%) for the training set, 294 sets of data (15%) for the validation set, and 294 sets of data (15%) for the testing set. The results showed that the MOCM-OPCC specimen with HBSA addition, painted interfacial agent, and MOCM layer thickness of 18 mm had the highest bond strength, which reached 1.56 MPa after curing to 28 d and still maintained high interfacial bond performance after erosion. The hybrid optimization model, GA-SVR, can significantly improve the prediction accuracy of the SVR model and exhibits obvious advantages in predicting the interfacial bonding performance between MOCM and OPCC. Compared with the SVR model, the MAE index error of the GA-SVR model was reduced by 28.57%, the RMSE index error by 20%, the R² coefficient increased by 3.23%, and the SMAPE error by 5.34%.

We employed Gleeble thermal-simulation experiments combined with color metallography, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) to systematically investigate the microstructural evolution and variation of retained austenite in U20Mn bainitic rail steel under different step-controlled cooling-quenching-tempering processes. Mechanical property tests, including tensile, impact, and reduction-of-area measurements, were performed to determine the optimal heat treatment parameters. The results indicate that austenitizing at 900 °C for 15 min, followed by step-controlled cooling at rates of 3 - 0.5–0.3 °C/s, air cooling to room temperature, and tempering at 300 °C for 4 h provides the best overall performance. Under these conditions, the steel exhibits a microstructure consisting of approximately 70.09% fine lath bainite and 29.91% martensite-film-like retained austenite, with an average bainitic lath width of about 147 nm. The optimized microstructure yields a tensile strength of 1 400 MPa, an elongation exceeding 20%, a reduction of area of about 55%, and a significantly enhanced impact toughness, with the impact energy increasing from about 60 J before tempering to above 85 J after tempering. By precisely controlling phase-transformation kinetics and refining the microstructure, the process achieves a balanced improvement in strength and toughness, ensuring better service performance of bainitic rail steel.

We developed a waterborne polyurethane (WPU)-reinforced silica aerogel composite through a sol-gel approach combined with ambient pressure drying. By systematically optimizing the WPU content, we fabricated WPU-SA composite aerogels that simultaneously achieve high mechanical strength and low thermal conductivity. Microstructural characterization via scanning electron microscopy (SEM) confirms the formation of an interpenetrating WPU-silica network, which effectively suppresses pore collapse during drying. The optimized composite with 8.0 wt% WPU loading demonstrates a exceptional thermal conductivity of 0.040 5 W/(m·K), an ultra-low density of 0.186 g/cm³, and a remarkable compressive strength of 2.21 MPa and good flame retardancy, representing a substantial improvement over pristine SA. This study provides a facile and scalable strategy for manufacturing high-performance, cost-effective aerogel thermal insulation materials with balanced mechanical and thermal properties.

This study examines the impact of alkali-activated slag and silica fume on the mechanical properties of red mud-based geopolymers. By partially replacing red mud with alkali-activated slag and silica fume, the response surface method was employed to evaluate factors affecting the geopolymer’s mechanical properties, resistivity, and electrochemical impedance at different curing ages. Additionally, the microstructure was analyzed using electrochemical workstations, X-ray diffraction, and scanning electron microscopy. The results indicate that when the mass percentages of slag, alkali, silica fume, and red mud are 18%, 3%, 3%, and 76%, respectively, the geopolymer achieves a 28-day compressive strength of 15.99 MPa, shear strength of 3.22 MPa, and maximum resistivity and electrochemical impedance values. Microstructural analysis reveals that with increasing curing age, hydration products increase, filling micropores and cracks, reducing porosity, and enhancing the strength of the three-dimensional network structure. Furthermore, a predictive model for compressive strength, resistivity, and curing age was established, showing good fitting. This research provides valuable insights into the comprehensive utilization of slag, silica fume, and red mud.

The expansion and upgrading of power grid systems is bringing rapid development to the regional economy along with high pressure to the ecological environment due to the difficult degradation of insulation protective cover in the surged retired cables, such as cross-linked polyethylene (XLPE) for the high-voltage power system. Thus, developing efficient and environmentally friendly technology for the recycling of insulating layer in retired cables has become an urgent challenge. To address such issue, homogeneous Ru-based catalysts loaded on different supports with rare earth metal (La, Pr, Y, and Ce) compounds are synthesized via a hydrothermal coprecipitation strategy for thermal catalytic cracking. Experimental results indicate that among the four rare earth elements, the Ru/La₂O₂CO₃ catalyst possesses abundant strong Lewis acid sites and highly dispersed Ru active sites, demonstrating excellent catalytic performance. Optimal performance was achieved around a Ru loading of 3 wt%, and experimental results indicate that the catalyst achieved a 98.4% conversion rate for crosslinked polyethylene and a 42.5% liquid product yield at 400 °C, containing a portion of high-value-added C5–C21 hydrocarbon components. Furthermore, the catalyst shows excellent stability with a maintained conversion rate of 93.8% after five cycles, demonstrating the catalytic enhancement of rare earth compounds and offering new insights for developing efficient thermal catalytic cracking of waste polymers.

The use of hydrophobic nano polymers to modify cadmium contaminated soil was proposed in this study. The water stability and strength of the modified soil were evaluated through immersion tests and UCS tests. Contact angle test and ICP-OES were used to measure soil water contact angle and cadmium leaching concentration, respectively, and to analyze the effects of hydrophobic polymers on soil hydrophobicity and heavy metal leaching. In addition, the mechanism of the nano polymer was studied through microstructural characterization techniques such as FTIR, TGA, and X-ray diffraction. The results showed that at a dose of 2% or higher, the soil remained intact after soaking for 24 hours, and the UCS value reached 0.799 MPa at a dose of 5% after soaking. At a dose of 5%, the soil water contact angle increased from 18.9 ° in untreated soil to 118.5 °, an increase of 6.3 times. The leaching concentration of cadmium in soil with an initial concentration of 100 mg/kg decreased to 0.78 mg/L, indicating that the nano polymer has significant hydrophobicity and excellent ability to inhibit heavy metal migration. Mechanism analysis shows that the oxysilane polymer in the nano polymer underwent hydrolysis and condensation of Si-H bonds to form Si-OH, which further reacts with hydroxyl groups on the soil surface to form a three-dimensional hydrophobic siloxane network (Si-O-Si). This network covers soil particles and effectively prevents water infiltration. In addition, surfactants based on fatty alcohols reduced the surface free energy of soil, thereby minimizing the migration of free cadmium. The research results can provide new ideas for the treatment of cadmium contaminated soil.

We produced polyaspartic acid ester (PAE) resin utilizing 4,4′-diaminocyclohexylmethane (PACM) and diethyl maleate (DEF) in order to prepare polyaspartic acid (PAE) polyureas with better primary amine conversion rates and superior adhesion and thermal stability qualities. The primary amine conversion rate of PAE resin was examined in relation to reaction temperature and duration. Results show that 75–80 °C is the ideal temperature, and 15 hours is the ideal reaction period. To find the best modification technique, 3-glycidoxypropyltrimethoxysilane (KH-560) and epoxy resin (E51) were used to modify PAE resin. The best modification percentage was 7%, resulting in a primary amine conversion rate of 92.72%. PAE polyurea was created by reacting the prepared PAE resin with isocyanate prepolymer, and it was then examined and described. The modified gel time was 17 minutes, and the surface drying time was 32 minutes. The coating demonstrated a tensile strength of 34.06 MPa, an adhesion strength of 5.53 MPa, a tear strength of 76.68 MPa, an elongation at break of 60.89%, and water absorption rate of 0.231%. The thermal stability of the polyurea coating layer was improved by the addition of epoxy resin and silicone modification, which raised the PAE polyurea’s thermal breakdown temperature.

Achieving both superior mechanical properties and thermal stability in epoxy resins remains a significant challenge. We designed a novel hyperbranched polysiloxane (HBPSi) containing specific epoxy and hydroxyl end groups as a toughening agent for epoxy resins to overcome the incompatibility of the toughening agent with the resin. Remarkably, a small amount of epoxy group-capped HBPSi not only enhanced the mechanical properties of the epoxy resins (DGEBA) but also increased its glass transition temperature. Compared with pure epoxy resin, the resin containing 3 wt% HBPSi not only has improved toughness, but also has significantly increased elongation at break and impact strength by 80.0% and 163.7%. It is worth noting that the improvement of toughness is not at the expense of mechanical strength and glass transition temperature. On the contrary, the mechanical strength and T_g of polysiloxane increased slightly with the introduction of end epoxide hyperbranched polysiloxane. In addition, SEM and DMA results show that HBPSi has good compatibility with epoxy resin. The above results show that the synthesized HBPSi can effectively improve the mechanical properties and thermal stability of epoxy resin, and broaden the application range of epoxy resin.

Iron-doped carbon dots (Fe-TrypCDs) were synthesized via a one-step hydrothermal method using tryptophan as the carbon precursor. The obtained nanoparticles exhibited uniform size distribution, good water solubility, and high fluorescence quantum yield. Fe doping effectively modulated the surface electronic structure, enabling reversible and stable pH-responsive fluorescence within the range of 2.0–8.0. This switching behavior is primarily attributed to the protonation/deprotonation of surface functional groups and Fe–ligand coordination, which alter electron density and charge transfer pathways. Cellular experiments demonstrated that Fe-TrypCDs were efficiently internalized by HK-2 cells, produced bright fluorescence imaging, and showed low cytotoxicity. This study provides a facile strategy for constructing pH-responsive fluorescent probes, offering promising potential for real-time monitoring of renal cellular microenvironments and related pathological processes.

Brittleness remains one of the primary barrier limiting the clinical application of zirconia-toughened alumina (ZTA) ceramics in total hip arthroplasty (THA). To address this limitation, we developed a novel series of ZTA ceramics through an energy-efficient microwave sintering process, employing ZnO at concentrations of 0–2.5 wt% as a multifunctional sintering additive. We systematically investigated the effects of ZnO content on phase composition, microstructure, and mechanical performance enhancement were systematically elucidated. The results showed introducing ZnO into ZTA significantly enhanced its overall performance. At the optimal ZnO content of 0.5 wt%, the composite achieved a relative density of 98.41%, a Vickers microhardness of approximately 1903.2 HV, and a flexural strength of 882.34 MPa. The enhancement of these properties stems from the dual role of zinc oxide: promoting densification and grain refinement. The in situ formed plate-like ZnAl₂O₄ spinel grains contribute to toughening through crack deflection and the pull-out effect. However, excessive introduction of spinel phases was found to compromise the overall material performance. Microwave sintering significantly improved the densification of ZTA ceramics at 1 500 °C compared to conventional sintering methods. Our findings demonstrate the potential of ZnO incorporation and microwave sintering in improving the properties of ZTA ceramics and provides a new strategy for the rapid preparation of high-performance ZTA ceramics.