To further enhance the low-temperature performance of high-viscosity asphalt in cold regions pavement and improve the pavement performance of its mixtures, this study introduced 10%, 12%, 14%, and 16% HVA high-viscosity additives into base asphalt to prepare high-viscosity modified asphalt. The fundamental properties were evaluated using three major performance indices and Brookfield viscosity tests, while low-temperature creep and stress relaxation tests were conducted to assess low-temperature rheological characteristics. Meanwhile, rutting, small-beam bending, and freeze-thaw splitting tests were performed to comprehensively evaluate the pavement performance of porous asphalt mixtures. The results indicate that incorporating HVA effectively improves the high-temperature shear resistance of asphalt. As HVA content increases, asphalt creep stiffness rises, creep rate decreases, and low-temperature cracking resistance is enhanced. HVA also reduces shear stress and improves the asphalt's stress relaxation capacity under low temperatures. However, excessive HVA content adversely affects the asphalt's low-temperature performance, with 14% identified as the optimal dosage. The OGFC-13 mixture produced using HVA-modified asphalt exhibits excellent high-temperature stability and water stability, and its flexural tensile strength and bending failure strain both surpass those of SBS-modified asphalt mixtures, demonstrating superior low-temperature cracking resistance.

As a novel supplementary cementitious material, the limestone-fly ash-cement (LF³) system exhibits excellent environmental adaptability and mechanical performance. However, the theoretical understanding of its hydration mechanisms and strength development remains limited. To address this gap, this study develops a hydration kinetics model for the LF³ system by comprehensively considering the hydration and pozzolanic reactions of limestone and fly ash. The model is based on the reaction mechanisms involving calcium hydroxide and aluminates, and introduces hydration-associated products (e.g., water and calcium hydroxide) as dynamic input variables to simulate the evolution of the ternary hydration process. Furthermore, incorporating Powers' strength theory, a strength prediction model driven by the degree of hydration is established, with model parameters calibrated and validated against published experimental data. Results show that the predicted strengths correlate well with measured values (R²=0.99, RMSE=1.48 MPa), indicating strong applicability and generalization capacity. The findings demonstrate that limestone enhances early-age strength, while fly ash contributes to long-term performance through pozzolanic reactions. Overall, the LF³ system outperforms binary blended cements and ordinary Portland cement. The optimal mix proportions shift from high-limestone/low-fly ash at early ages to high-fly ash/low-limestone at later ages. This study provides theoretical support for understanding the hydration mechanism and mix design optimization of LF³ systems, and offers a predictive tool for designing low-carbon, high-performance concrete.

To enhance the thermal conductivity of phase change materials (PCMs), address the leakage issue, and improve the thermal management capability of photovoltaic/thermal (PV/T) integrated systems, this study prepared a binary PCM using polyethylene glycol 2000 (PEG-2000) and capric alcohol (CP), with an optimal mass ratio of 3∶7 deter mined. Subsequently, graphene (GR) was incorporated to further improve the performance, resulting in the preparation of a PEG-2000-CP/GR composite PCM. The compatibility, thermal properties, adsorption capacity, and stability of the composite PCM were evaluated. The experimental results indicate that there are only physical interactions among the components of the composite material, with no chemical reactions occurring. After adding 15 wt% GR, the thermal conductivity of the composite material increases to 1.6313 W/(m·K), which is 11.5 times higher than that of the binary material. The latent heat of phase change reaches as high as 189.4 kJ/kg. The leakage rate during the phase change process is controlled within 4%, demonstrating good adsorption capacity. After 100 thermal cycling tests, the enthalpy decay rate is only 3%, and the thermal conductivity remains at 83.5% of its initial value, indicating high cycling stability. This study develops a composite PCM with excellent performance, which offers significant improvements in thermal conductivity, heat storage density, and service life compared to traditional PCMs. It provides a basis for optimizing PV/T systems and holds important application value.

With the continuous increase in power density of high-performance computing chips, traditional heat dissipation technologies are facing severe challenges. Aiming at the heat dissipation requirements of high-power density chips, this paper investigates the thermal characteristics of diamond-composite copper heat sinks in single-phase immersion cooling systems using numerical simulation methods. By establishing a three-dimensional fluid-solid coupling heat transfer model, the influence of diamond wafer diameter on heat dissipation performance is systematically analyzed. The research results show that increasing the diameter of the diamond wafer significantly improves the temperature uniformity at the bottom of the heat sink. When the diameter increases from 51 mm to 78 mm, the average temperature of the heat source surface decreases by 3.01 K, and the temperature NU (Non-Uniformity) stabilizes at 1.79%. The high thermal conductivity of the diamond wafer significantly enhances the heat transfer capacity of the system. The decrease in heat sink efficiency with the increase in diamond wafer diameter reflects the improvement of the system's heat dissipation potential, and the Nusselt number increases by 14.4% with the increase in diameter. The total thermal resistance of the heat sink decreases with the increase in diamond wafer size, reaching 0.064 K/W when the diameter is 78 mm. This study provides important design references for the thermal management of high-power density electronic devices.

Driven by the global "dual-carbon" goal, water electrolysis has emerged as a key pathway for green hydrogen production. However, its large-scale application is hinder by the high cost and scarcity of platinum-based catalysts. Transition metal carbides (TMCs) exhibit platinum-like catalytic activity due to their unique electronic structures. Despite this promise, understanding the "composition-structure-performance" relationship in TMCs remains largely dependent on traditional trial-and-error methods, highlighting the urgent need for data-driven and efficient modeling approaches. In this study, a multi-dimensional database containing 117 sets of experimental data on TMCs was constructed. Four machine learning algorithms, namely support vector regression (SVR), K-nearest neighbor (KNN), random forest regression (RF), and extreme gradient boosting (XGBoost), were employed to predict the performance of the hydrogen evolution reaction, specifically focusing on overpotential (η₁₀) and Tafel slope. Comparative analysis revealed that RF and XGBoost are significantly outperformed KNN and SVR in terms of generalization capability. Notably, RF achieved the lowest prediction error for η₁₀ (RMSE of the test set=0.14119), while XGBoost demonstrated the highest predictive accuracy for the Tafel slope (R² of the test set=0.55423). Through the SHAP (Shapley Additive Explanations) interpretability analysis, it was found that the carbonization temperature, carbon mass fraction, platinum and molybdenum contents are the key factors affecting the catalytic performance. Based on machine learning model prediction and SHAP interpretability analysis, an optimal parameter combination of carbonization temperature 971.12 ℃, carbon mass fraction 23.61 wt%, Pt mass fraction 1.08 wt%, and Mo mass fraction 79.66% was obtained through 100 generations of genetic algorithm iteration optimization, with its predicted performance of overpotential 126.93 mV and Tafel slope 83.92 mV/dec superior to 75% of the dataset samples. This work provides a data-driven paradigm for the high-throughput screening and rational design of TMCs catalysts, offering a promising approach to optimizing the performance of non-noble metal catalysts.

This paper mainly summarizes the research on the factors influencing the microstructure and properties of aluminum bronze, which are preparation methods, heat treatment processes and microalloying, aiming to provide certain guidance and reference for determining the optimal alloy composition of aluminum bronze and formulating the best heat treatment process. It elaborates on the effects of various preparation methods, heat treatment process parameters, and different trace alloying elements on the microstructure (such as α phase, β phase, γ₂ phase, and κ phase) and properties (such as strength, hardness, elongation, wear resistance, and corrosion resistance) of aluminum bronze alloys. The results show that the main heat treatment process for aluminum bronze is solution aging treatment, which can significantly improve the mechanical properties of aluminum bronze alloys, and the selection of appropriate process parameters is also extremely important. Adding appropriate amounts of alloying elements such as Ni, Ti, Mn, and Cr can significantly improve the mechanical properties, corrosion resistance, and processing performance of aluminum bronze alloys through optimizing phase composition, strengthening the matrix, and improving interface performance. Finally, the future development of aluminum bronze is prospected.

Geopolymer, a novel type of green cementitious material, holds the significant importance for the comprehensive utilization of bulk industrial solid waste and the reduction of using of energy-intensitive, carbon-emissive cement cementitious materials. The microscopic molecular models of materials, constructed based on Newtonian mechanics and powerful computer modeling, can fundamentally describe the motion of molecules or atoms, facilitating a complete insight of the properties of atoms or molecules within the system and their interactions. This paper reviews recent advancement of constructing and optimizing of models in the molecular dynamics simulation of geopolymers, introduces simulation calculations of their microstructures such as radial distribution functions, bond lengths, and bond angles, as well as application examples analyzing and predicting macroscopic properties including mechanical, thermodynamic, and dynamic behaviors, and microscopic properties such as ions diffusion and interfacial bonding. The development directions of the molecular dynamics simulation of geopolymers, including developing specialized force fields tailored for geopolymer simulations, creating more diverse molecular dynamics models suitable for complex geopolymer systems to conduct in-depth research on the relationship between microstructure and macroscopic properties, and performing the simulation calculations under extreme conditions and complex environments involving multi-physics coupling, are proposed.

Electrochemical devices such as fuel cells and flow batteries offer promising solutions for addressing global energy and environmental challenges. However, high-performance proton exchange membrane (PEM) remains a critical technical challenge impeding the progress of these devices. Traditional perfluorosulfonic acid membranes (PFSA) have been commercialized but are hindered by high costs and inadequate stability. Sulfonated polyimides (SPI) have become a research focus due to their excellent thermal stability, mechanical strength, and adjustable proton conductivity. Therefore, this review systematically summarizes the structure, proton conduction mechanisms, and preparation methods of SPI, with a focus on its recent advancements of monomer optimization, chain branching/crosslinking and composite modification. It aims to further advance the structural design and applications of SPI.

Scheelite structure represented by CaWO₄ contains isolated tetrahedral moieties with deformation and rotation flexibility, which facilitates the accommodation of oxygen vacancy and interstitial oxygen defects as well as the long-term transportation of charge carriers. It is known as potential candidates in inorganic solid-state oxide ion conductors. In order to develop directionally novel materials with excellent oxide ion conductivity and regulate the oxide ion conduction of related devices, this article reviews the structure-property correlation of scheelite structural oxide ion conductors and comprise the effect of dopants on oxide ion conductivity in different scheelite compositions. Then we summarize the stabilization of oxygen defects and migration mechanism of oxygen ions in different scheelite oxides. Finally, we prospect the future development direction of scheelite structure in solid-state ionic conductors.

Bone tissue engineering, particularly in the construction of functional bone grafts, demonstrates significant potential. Two extremely promising new materials in this field are graphene oxide (GO) and extracellular vesicles (EVs). The combined requirements for bioactivity and structural support in bone repair are met by GO's remarkable mechanical strength and biocompatibility. By transporting bioactive molecules, such as proteins and nucleic acids, EVs serve as key mediators of intercellular communication and provide unique advantages in cell-free therapeutic approaches. For bone regeneration, both are thought to be groundbreaking materials. The characteristics of GO and the biogenesis/isolation procedures of EVs are described in this article. It systematically reviews their current applications in bone repair and provides an in-depth summary of their mechanistic roles within bone tissue engineering. Lastly, a thorough analysis of the advantages and challenges of GO and EVs in bone regeneration is provided. We conclude with perspectives on the future development of GO-EVs complexes for bone tissue regeneration and present the novel idea of a GO-EVs composite as a drug delivery platform.

Two-dimensional Ti₃C₂T_x, due to their unique micro-layered structure and excellent physical and chemical properties, are regarded as new and efficient electromagnetic interference shielding materials. Ti₃C₂T_x films are prepared by stacking two-dimensional nanosheets, therefore the performance of individual Ti₃C₂T_x nanosheets and the orderliness of nanosheets arrangement in the film both determine the electromagnetic shielding performance of Ti₃C₂T_x films. Based on the differential centrifugation method, Ti₃C₂T_x films were prepared from screened two-dimensional large-sized nanosheets. The chemical composition, crystal structure and microstructure of Ti₃C₂T_x were characterized by X-ray diffraction, transmission electron microscopy and scanning electron microscopy. The electrical conductivity and electromagnetic shielding performance of Ti₃C₂T_x were studied with four-probe tester and vector network analyzer. The results showed that the large-sized Ti₃C₂T_x nanosheets are regularly and orderly arranged in the film, and the conductivity of Ti₃C₂T_x films with a nanosheet size of over 6 μm can reach 1.62×10⁵ S/m, which is 1.5 times that of films prepared from small-sized nanosheets. The electromagnetic shielding performance of obtained Ti₃C₂T_x films can reach up to 64.8 dB. Meanwhile, the unit thickness electromagnetic shielding efficiency of Ti₃C₂T_x film reached 4.3×10⁶ dB/m at a thickness of 11 μm.

Preparation of flexible polyorganosiloxane aerogels by constructing organic-inorganic hybridization networks through silicone precursors can significantly improve the brittleness of conventional silicon dioxide (SiO₂) aerogels, but the introduction of organic components in the structure leads to the deterioration of the thermal stability of the aerogels, which limits their application in high-temperature environments. Based on this, in this work, poly(vinylpoly(methylsiloxane) (PVPMS)/SiO₂ hybridized aerogels were prepared by sol-gel process using high-temperature-resistant inorganic nanofillers enhancement. The effect of SiO₂ dosage on the microstructure and physico-mechanical properties of PVPMS/SiO₂ aerogel was systematically investigated. The results show that the resulting aerogel has a light density of 91 mg/cm³, a low vesicle diameter of 52 nm, and a high specific surface area of 560 m²/g. At 80% compressive strain, a compressive strength of up to 4.84 MPa is obtained. The aerogel shows excellent thermal stability with the initial heat-loss temperature dramatically increasing from 227 ℃ for the PVPMS aerogel to 295 ℃, thermal insulating properties with thermal conductivity as low as 21.2 mW/(m·K) and hydrophobicity with static water contact angle>127°. As a result, the lightweight and high-performance hybridized aerogel material is expected to be used in building energy efficiency, aerospace and other fields.

The (Ni/C)/UV resin electromagnetic metamaterials were prepared by 3D printing, and the effects of nickel source addition (0, 0.5, 1.0 and 1.5 g) in Ni/C fillers on the microwave absorption bandwidth of (Ni/C)/UV resin electromagnetic metamaterials were studied. The results show that with the increase of nickel source, the microwave absorption bandwidth of the prepared (Ni/C)/UV resin sample shows a trend of first widening and then narrowing. When the nickel source addition is 1.0 g, the (Ni/C)/UV resin sample has a microwave absorption bandwidth of 5.9 GHz, which is significantly higher than that of the sample with 0 nickel source addition (3.9 GHz). The metal Ni not only enhances the magnetic loss of the sample, but also enhances the dielectric loss of the sample due to its catalytic graphitization, which synergizes to improve the microwave attenuation coefficient of the sample and broaden the microwave absorption bandwidth of the sample. The above studies clarified the influence of nickel source addition on the microwave absorption bandwidth of (Ni/C)/UV resin electromagnetic metamaterials, which provided an effective reference for the research of such materials, and the 3D printing preparation method adopted in this study also provided a new idea for the exploration of the preparation process of new microwave absorbing materials.

The g-C₃N₄/Bi₂WO₆ composite was synthesized by a hydrothermal method. Bi₂WO₆ nanosheets were grown on the surface of layered g-C₃N₄. The phase composition, morphology, optical properties, and band structures of g-C₃N₄, Bi₂WO₆ nanosheets, and the g-C₃N₄/Bi₂WO₆ composite were characterized using XRD, SEM, FT-IR, UV-vis, XPS, and PL. The photocatalytic degradation performance of the samples toward tetracycline hydrochloride (TC) was investigated. The results reveal that in the g-C₃N₄/Bi₂WO₆ composites, Bi₂WO₆ nanosheets were distributed on the surface of g-C₃N₄ and the two components were in close contact. The photocatalytic activity of 10-CN/BWO under visible light irradiation was significantly enhanced. The degradation rate of TC reached 88.03% after 120 min visible light irradiation. The kinetic rate constant was 1.33 times higher than that of pure g-C₃N₄ and 1.21 times higher than that of pure Bi₂WO₆. The degradation rate remained at 81.01% after five cycles, demonstrating good stability. FT-IR and XPS analyses showed that an interfacial heterojunction was formed between g-C₃N₄ and Bi₂WO₆. Radical trapping experiments revealed that photogenerated holes (h⁺) and superoxide radicals (O^-₂) are the main active species in the photocatalytic degradation process. The i-t and PL results indicated that the heterojunction at the g-C₃N₄/Bi₂WO₆ interface facilitated the migration and separation of photogenerated charge carriers, which improved the photocatalytic activity.

Using corncob cellulose (CC) and humic acid (HA) as raw materials, with acrylic acid (AA) and 2-acrylamido-2-methylpropanesulfonic acid (AMPS) as polymer monomers, a corncob cellulose/humic acid/AMPS/AA superabsorbent resin (IS-CC/HA-g-P(AMPS/AA)) was prepared via inverse suspension polymerization to achieve resource utilization of waste materials. The individual factors influencing the water absorption capacity of the resin were investigated. Through orthogonal experiments, the optimal preparation conditions were determined as: potassium persulfate (KPS) 0.075 g, N,N'-methylenebisacrylamide (MBA) 0.005 g, Span 80 0.175 g, AMPS:AA ratio 1∶2, neutralization degree 65%, and CC:HA ratio 1∶2. Under these conditions, the prepared resin demonstrated maximum water absorption of 902.01g/g and saline absorption of 100.31 g/g. Fourier transform infrared (FT-IR) spectroscopy confirmed successful graft copolymerization of CC and HA. Scanning electron microscopy (SEM) analysis revealed larger and denser pore structures in IS-CC/HA-g-P(AMPS/AA), while thermogravimetric analysis (TGA) indicated good thermal stability of the composite resin.

The lattice structure, electronic structure and elastic properties of the MnAl₆ phase were calculated under pressures ranging from 0 to 50 GPa based on the first principles that study the influence of MnAl₆ on Zn-Al alloys. The density of states and energy bands indicate that the electronic structure of the MnAl₆ has a shallow and wide pseudo-band gap near the Fermi level, with weak covalent bonds coexisting with metallic bonds. The differential charge density shows that the charge transfer from Mn to Al dominates the ionic bond characteristics. In terms of mechanical properties, both the elastic constant and the elastic modulus increase with the increase of pressure, and the stiffness of the MnAl₆ also increases. Among them, the bulk modulus B increased from 99.63 GPa to 275 GPa, and the shear modulus G increased from 70.38 GPa to 131.83 GPa. MnAl₆ demonstrated better compressive resistance and stronger shear stiffness under high pressure. The Young's modulus E increased by 170.25 GPa with pressure, and the axial stiffness of enhanced under high pressure. The Poisson's ratio v and G/B values change at 20 GPa, causing the MnAl₆ to shift from brittleness to ductility. It exhibits good ductility under high pressure and can exhibit significant resistance to deformation during tensile testing. These results are helpful to provide microscopic theoretical guidance for the subsequent experimental research and application of Zn-Al-Mn alloys.

Grade II fly ash was finely ground using a ball mill to obtain ultrafine fly ash (UFA) with a large specific surface area. UFA was partially substituted for cementitious materials in concrete to prepare ultrafine fly ash recycled concrete. The influence of UFA substitution rate on the microstructure, phase structure, mechanical properties, and salt erosion resistance of recycled concrete was systematically studied. The results showed that the specific surface area of ultrafine crushed fly ash could reach 1 038.4 m²/kg, with a diameter distribution between 10-50 μm. The replacement of cement with ultrafine fly ash accelerated the hydration reaction, increasing the density of recycled concrete. The 30%UFA sample exhibited the optimal hydration performance control effect, with a maximum heat released rate of 5.49 mW/g. The compressive strength of the 30%UFA sample reached a peak of 37.3 MPa, an increase of 11.01% compared to the 0%UFA sample. The flexural performance remained stable and good, achieving a maximum strain of 3.07%. After 150 cycles of salt freezing, the relative dynamic elastic modulus of the 30%UFA sample reached its maximum value of 68.1%, with a minimum mass loss rate of 2.08%, indicating optimal durability performance. Microscopic analysis showed that UFA significantly improved the interfacial transition zone structure and pore characteristics of recycled concrete through the dual effects of micro aggregate filling effect and volcanic ash activity. The research results provide a new approach for the high-value utilization of fly ash, and the developed ultrafine fly ash recycled concrete is suitable for construction projects in coastal and cold regions, with significant economic and environmental benefits.

The Solid-Liquid Hybrid Rocket (SLR) motor nozzle possessed more complex ablation process with dual oxidation and particle erosion, which impact on anti-ablation properties of SLR nozzle. However,the actual ablation performance under particle scouring cannot be obtained by oxygen-acetylene ablation method. In this paper, the effect of Al particles contents on ablation process of C/C-SiC-ZrC composites were studied by hot-firing test of the SLR motor. Above all, the ablation rate was obsessed by hot-firing test, the ablation morphologies and the elements distribution were observed by SEM, the ablation products structure were tested by XRD, and the ablation principle was established combined with relative test and simulated analysis. According to the research, The ablation rate for C/C-SiC-ZrC composites under pure HTPB was0.001mm/s, that value for C/C-SiC-ZrC composites under HTPB combined with 20% Al particles was0.105mm/s,which indicated that the ablation rate was increasing rapidly with the content of Al particles increased in the SLR motor, and the ablation mode changed from oxidation to denudation,the aggravated deterioration was attributed to the ceramic matrix corrosion by the Al particles and oxidation products.

The WO₃-based gasochromic hydrogen sensor can directly detect hydrogen leakage through visual observation without additional power supply, which has the unique advantages of timeliness, convenience and low cost in the fields such as wearable hydrogen safety signs and hydrogen pipeline transportation. However, the hydrogen-sensitive color-changing mechanism of WO₃ and the influence of oxygen vacancies are still unclear, which restricts the performance improvement and popularization of WO₃-based gasochromic hydrogen sensors. Based on this, WO₃ films with adjustable oxygen vacancy concentration were designed and fabricated by reactive magnetron sputtering technology, and the films composition, color, elemental valence state and oxygen vacancy concentration were studied. The color response of different Pd/WO₃ films to hydrogen was explored, and it was found that increasing the concentration of oxygen vacancies in WO₃ films could improve the sensitivity of hydrogen, but when the oxygen content in WO₃ films was too low, the presence of W⁵⁺ and metallic tungsten would make the color of the film itself darker, and the hydrogen-sensitive coloring characteristics would disappear. For the amorphous Pd/WO₃ film with high oxygen vacancy concentrations, the optimal working temperature was 200°C, the response color difference to 1% H₂ reached 102.4, and the response time was only 15 s.

Nicke oxide (NiO) is a prevalent wide bandgap p-type semiconductor frequently employed in the fabrication of p-type solar cells or integrated with semiconductor devices to enhance the optoelectronic properties of photovoltaic devices. When combined with an n-type photoanode to form a p-n tandem dye-sensitized solar cell, it can significantly enhance the absorption spectrum range and open-circuit photovoltage of the cell. In this study, NiO thin films were synthesized on fluorine-doped tin oxide (FTO) glass substrates using the sol-gel method, and the performance of NiO thin films was improved through Li doping. Various concentrations of lithium-doped NiO films were prepared, and their phase and morphology were characterized through X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). These electrodes, following sensitization with CdSe quantum dots, were utilized as photoanodes in dye-sensitized solar cells, and their photoelectrical performance was evaluated. The findings indicate that the Li-doped NiO thin films produced via the sol-gel method exhibit a cubic phase with a spherical porous structure, possessing an average particle size of approximately 30 nm. The dye-sensitized solar cell fabricated with a doping concentration of 0.5 atomic percent Li in the NiO film demonstrated optimal performance, achieving a photocurrent density of 4.19 mA/cm², an open-circuit voltage of 0.208 V, a fill factor of 36%, and a power conversion efficiency of 0.31%.

The development of photocatalysts with both excellent visible light responsiveness and efficient photogenerated carrier separation efficiency can efficiently degrade and treat organic wastewater. In this paper, to address the limited photocatalytic activity of graphitic-phase carbon nitride (g-C₃N₄), an OCN/CdS heterojunction photocatalyst was constructed by loading CdS nanoparticles on the surface of OCN by hydrothermal method based on oxygen-doped g-C₃N₄ (OCN) nanosheets. As the OCN nanosheets and CdS nanoparticles were compounded through the interface, a point-surface multidimensional three-dimensional interwoven structure was formed, which provided sufficient space for the photocatalytic reaction. Compared with OCN, OCN/CdS showed enhanced visible light absorption and narrower bandgap, in which the bandgap of 20%-OCN/CdS was reduced to 2.35 eV. The carrier separation efficiency of 20%-OCN/CdS was significantly enhanced, with the lowest charge migration impedance and the strongest photocurrent response. In the MB photocatalytic degradation, the 20%-OCN/CdS sample degraded up to 92.2% of MB within 60 min, and its reaction rate constant was 1.59 times of that of OCN, with excellent visible photocatalytic activity. The mechanism was found that the photocatalytic degradation of MB by OCN/CdS followed a Z-type heterojunction mechanism with ·O₂- as the main active species, and the electrons in the conduction band of CdS and the holes in the valence band of OCN were complexed at the interface, which realized the synergistic enhancement of space charge separation and redox ability. The findings in this paper can provide a useful reference for the construction of efficient heterojunction photocatalysts.

Expanded polystyrene (EPS) particles have advantages such as closed cell structure and lightweight, and have important engineering application value in improving the insulation performance of foam concrete. EPS particle foam concrete was prepared using P·O 42.5 grade cement as the raw material and EPS particles as the additive phase. The effects of EPS particle doping amount on the microstructure, mechanical properties, insulation performance and frost resistance of foam concrete were studied by XRD, SEM, TGA, and salt freezing cycle testing. The results showed that the introduction of EPS particles delayed the hydration process of cement. The addition of EPS particles had little effect on the proportion of harmful pores between 50-200 mm, but effectively reduced the proportion of severe harmful pores above 200 mm. The proportion of severe harmful pores in the EPS9% sample decreased to a minimum of 19.58%, the proportion of harmless pores was the highest at 59.45%, and the proportion of low harmful pores was the highest at 12.95%. The EPS9% sample exhibited the best ductility performance, with a fracture point displacement of 0.41 mm and a maximum fracture energy of 707 N·mm. The thermal insulation performance of foam concrete was improved by adding appropriate amount of EPS particles. The minimum thermal conductivity of the EPS9% sample was 0.066 W/(m·K). With the increased of EPS particle content, the compressive strength of concrete samples first slightly decreased and then slightly increased. After 100 salt freezing cycles, the compressive strength of the EPS9% sample reached a maximum of 24.7 MPa, the lowest mass loss rate was 1.06%, and the maximum relative dynamic elastic modulus was 84.41%. Compared with the EPS0% sample, the mechanical properties and frost resistance were significantly improved.

Polyimide has been widely used in the preparation of high-temperature polymer-based dielectric films based on the outstanding physical and chemical properties, but different molecular structures significantly influence the dielectric properties and breakdown strength. In this study, four kinds of polyimide, soluble polyimide (sPI), polyamide-imide (PAI), polyetherimide (PEI) and ternary copolymer polyimide (P84), were investigated to explore the effects of differential molecular structures on the aggregation state, dielectric properties, and breakdown strength across a wide temperature range. The results demonstrate that the presence of high-dipole-moment amide bonds in PAI effectively enhances its polarization strength and dielectric constant. Additionally, XRD tests and simulation results reveal that the ether linkages in PEI disrupt the regularity of molecular chains and break the π-π conjugation of benzene rings, thereby inhibiting electron cloud movement. Among the four PIs, PEI exhibits the largest intermolecular chain spacing and achieves Weibull breakdown strengths of 604.4 MV/m at 25 ℃ and 410.1 MV/m at 150 ℃, respectively, outperforming sPI, PAI, and P84. This study provides a theoretical foundation for the preparation of high-temperature polymer dielectric films.

To investigate the durability of steel slag fine aggregate concrete (SSC) under salt solution and freeze-thaw cycles (S-FTC), mechanical tests were first conducted to determine the optimal dosages of steel slag fine aggregate (SSA) and fly ash (FA). Subsequently, S-FTC tests were carried out on concrete specimens to systematically analyze the effects of SSA and FA contents on mass, relative dynamic modulus of elasticity, and compressive strength. Furthermore, the GM(1,1) model based on grey theory was introduced to establish a predictive model for the S-FTC resistance of SSC using the measured relative dynamic modulus, followed by error analysis and service life prediction. The results indicate that a 30% SSA replacement effectively improves the durability of SSC under S-FTC. The combined incorporation of 10% FA further delays the degradation of mass and dynamic modulus, though it has limited effect on compressive strength enhancement. The predicted values obtained from the GM(1,1) model show good agreement with experimental results, with an average relative error below 2.6%. Under S-FTC exposure, the service life of SSC with 30% SSA is extended by approximately 10%-30% compared to natural concrete (NC), and a further 5%-20% increase in service life is achieved with the additional incorporation of 10% FA. Therefore, the GM(1,1)-based predictive model enables relatively accurate quantitative evaluation of the S-FTC resistance of SSC.

Using the sodium aluminate solution obtained from coal fly ash that has undergone calcination and acid leaching as an aluminum source, γ-AlOOH adsorbents with a fluffy microsphere morphology were synthesized via a hydrothermal method. Characterization techniques including SEM, XRD, FT-IR, BET-BJH, TGA, and Zeta potential were employed to systematically investigate the crystal structure, micromorphology, and surface properties of γ-AlOOH. Furthermore, the adsorption performance of γ-AlOOH in simulated wastewater containing Congo red was assessed. The results demonstrated that under experimental conditions of 25°C and pH 4, with an adsorbent dosage of 50 mg and an initial Congo red concentration of 200 mg/L in a 200 mL solution volume, the equilibrium adsorption capacity of γ-AlOOH for Congo red reached 776.45 mg/g, with a removal efficiency as high as 97.05% after adsorption equilibrium. Additionally, the adsorption process conformed to the pseudo-second-order kinetic model and the Langmuir isotherm model, indicating that the adsorption behavior was dominated by monolayer chemical adsorption. The thermodynamic analysis revealed that the adsorption of Congo red by the adsorbent was spontaneous, endothermic, and resulted in an increase in disorder.

The instability of Cu⁺ active species in copper-based electrocatalysts leads to decreased selectivity for C₂₊ products, particularly ethylene, during the electrocatalytic CO₂ reduction reaction (CO₂RR). In this study, by introducing rare earth element cerium (Ce), the bimetallic CuCeBTC metal organic framework (MOF) was used as the precursor, and its derived oxide catalyst (CuCeO_x) was prepared by calcination at 350°C. The catalyst was systematically characterized and its electrochemical performance was evaluated. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis confirmed the presence of Cu⁺ species and mixed valence state of cerium (Ce³⁺/Ce⁴⁺) in the CuCeO_x-2 catalyst with the optimal Ce doping amount. The electrochemical performance tests show that the ethylene Faraday efficiency (FE) of CuCeO_x-2 can reach 45.5% at -1.3 V (vs. RHE), which is significantly improved by 50% compared with the undoped CuO_x catalyst (FE_C2H4 = 30.3%), and the stability can be maintained for more than 12 h. Studies have shown that cerium doping can effectively stabilize the active Cu⁺ species and optimize the electronic structure of the catalyst through the electron buffering effect of Ce³⁺/Ce⁴⁺ redox pairs, enhance the adsorption of the key intermediate *CO, and promote the C—C coupling reaction, thereby significantly improving ethylene selectivity. This study provides a new idea for the design of efficient and stable CO₂RR catalysts.