We took Co_0.2Ni_0.8-MOF-74 with bimetallic synergistic effect as the basic material, and selected rare earth ions Ho, Gd, and Er with ion radii close to Co and Ni as the research objects for doping. The influence of rare earth ion doping amount and doping type on the eNRR performance of the catalyst was explored. The experimental results show that the ammonia yield rate and Faraday efficiency doped with Co_0.2Ni_0.8-MOF-0.5Ho are the highest, reaching 1.28 × 10⁻¹⁰ mol·s⁻¹·cm⁻²/39.8%, which is higher than the 1.12 × 10⁻¹⁰ mol·s⁻¹·cm⁻²/32.2% of Co_0.2Ni_0.8-MOF-74, and is about 14.3%/23.7% higher than that without doping, respectively. And the stability of Co_0.2Ni_0.8-MOF-0.5Ho is good(after 80 hours of continuous testing, the current density did not significantly decrease). This is mainly due to doping, which gives Co_0.2Ni_0.8-MOF-74 a larger specific surface area and catalytic active sites. The catalyst doped at the same time has more metal cation centers, which increases the electron density of the metal centers and enhances the corresponding eNRR performance.

On the basis of coordinated electrodeposition of carboxylated chitosan (CCS), we presented a green method to prepare Cu NCs and Cu NCs/CCS nanocomposite films. The method shows a range of benefits, such as the convenient and eco-friendly process, mild conditions, and simple post-treatment. The experimental results reveal that a homogeneous deposited film (Cu NCs/CCS nanocomposite film) is generated on the Cu plate (the anode) after electrodeposition, which exhibits an obvious red florescence. The results from TEM observation suggest there are nanoparticles (with the average particle size of 2.3 nm) in the deposited film. Spectral analysis results both demonstrate the existence of Cu NCs in the deposited film. Moreover, the Cu NCs/CCS film modified electrode is directly created through electrodeposition of CCS, which enables promising application in the electrochemical sensing. By means of fluorescence properties of Cu NCs, the Cu NCs/CCS film also owns the potential in fluorescence detection. Therefore, this work builds a novel method for the green synthesis of Cu NCs, meanwhile it offers a convenient and new electrodeposition strategy to prepare polysaccharide-based Cu NCs nanocomposites for uses in functional nanocomposites and bioelectronic devices.

Based on the structural characteristics of the high-speed loading tester, a four-point bending test device was designed to carry out the four-point bending strength test of glass under the action of static load and different impact velocities, and the formulae for calculating the maximum dynamic stress and strain rate of glass specimens under the action of impact loads were derived. The experimental results show that the bending strength values of the glass under dynamic impact loading are all higher than those under static loading. With the increase of impact speed, the bending strength value of glass specimens generally tends to increase, and the bending strength value increases more obviously when the impact speed exceeds 0.5 m/s or higher. By increasing the impact velocity, higher tensile strain rate of glass specimens can be obtained because the load action time becomes shorter. The bending strength of the glass material increases with its tensile strain rate, and when the tensile strain rate is between 0 and 2 s⁻¹, the bending strength of the glass specimen grows more obviously with the strain rate, indicating that the glass bending strength is particularly sensitive to the tensile strain rate in this interval. As the strain rate increases, the number of cracks formed after glass breakage increases significantly, thus requiring more energy to drive the crack formation and expansion, and showing the strain rate effect of bending strength at the macroscopic level. The results of the study can provide a reference for the load bearing and structural design of glass materials under dynamic loading.

In order to explore the effect of artificial accelerated aging temperature on the performance of carbon fiber/epoxy resin composites, we used artificial seawater as the aging medium, designed the aging environment of seawater at different temperatures under normal pressure, and studied the aging behavior of carbon fiber/epoxy composites. The infrared spectroscopy results show that, with the increase of aging temperature, the degree of hydrolysis of the composite is greater. At the same time, after 250 days of aging of artificial seawater at regular temperature, 40 and 60 °C, the moisture absorption rates of composite materials were 0.45%, 0.63%, and 1.05%, and the retention rates of interlaminar shear strength were 91%, 78%, and 62%, respectively. It is shown that the temperature of the aging environment has a significant impact on the hygroscopic behavior and mechanical properties of the composite, that is, the higher the temperature, the faster the moisture absorption of the composite, and the faster the decay of the mechanical properties of the composite.

Co/NC catalysts modified with rare earth elements (La, Ce, Pr) were prepared by pyrolysis of rare earth elements doped ZIF-67. The experimental results show that the modification of rare earth elements significantly improves the ammonia decomposition activity and stability of the Co/NC catalyst. The La-Co/NC catalyst can achieve an 82.3% ammonia decomposition and 18.4 mmol hydrogen production rate at 550 °C with a GHSV of 20 000 cm³·h⁻¹. Furthermore, no obvious performance degradation is observed after 72 hours of reaction for all rare earth elements modified catalysts. It is shown that the modification of rare earth elements significantly improves the surface alkalinity and surface chemical state of the catalyst, and thus improves the ammonia decomposition activity of the catalyst. A new type of high-performance ammonia decomposition Co-based catalyst is proposed, and the promoting effect of rare earth elements on the activity of ammonia decomposition is revealed.

Cu⁺-doped alkali borosilicate glasses with different Na₂O contents were prepared by the melting method, and the effects of different R values (R=Na₂O/B₂O₃) on the structure, ion presence state and luminescence properties of Cu⁺-doped alkali borosilicate glasses were investigated. The analysis by FT-IR and Raman spectroscopy shows that, with the increase of R value of the glass, the [BO₃] in the structure of Cu⁺-doped alkali borosilicate glass transforms into [BO₄] and the number of non-bridging oxygen in the glass network appears to be slightly increased. The absorption spectra and EPR analysis reveal that the Cu⁺ content in the glass gradually decreases and the Cu²⁺ content gradually increases as the R value of the glass increases. XPS and PL tests further indicate that the transformation of the octahedral coordination structure of Cu⁺ to the octahedral coordination structure of Cu²⁺ and the cubic coordination structure of Cu⁺ occurs in the glass as the R value of the glass increases. This transformation can effectively reduce the concentration quenching phenomenon of Cu⁺ and improve the fluorescence luminescence intensity of the glass samples. Meanwhile, the samples were found to have luminescence tunability as well as good thermal stability.

A series of tungstate red phosphors K_1−xLi _xEu(WO₄)_2−y(SO₄) _y were successfully prepared by sol-gel method, and the effects of the introduction of Li⁺ and SO₄ ²⁻ on the fluorescence intensity and thermal quenching properties of the prepared K_1−xLi _xEu(WO₄)_2−y(SO₄) _y phosphors were investigated. The X-ray diffraction data show that the prepared (Li⁺ and SO₄ ²⁻)-doped KEu(WO₄)₂ phosphors have a monoclinic tetragonal structure. In addition, the emission intensities of all the observed emission peaks change significantly with the increase of Li⁺ doping concentration, especially the intensity of the emission peaks at 615 nm fluctuated significantly and reached the maximum at x = 0.3 and y = 0.2. The K_1−xLi _xEu(WO₄)_2−y(SO₄) _y phosphors are found to have the highest fluorescence intensity at x = 0.3 and y = 0.2. Moreover, the K_0.7Li_0.3Eu(WO₄)_1.8(SO₄)_0.2 phosphor has better thermal quenching properties and luminescence efficiency, and the experimental results indicates that the fluorescence intensity and thermal burst performance of KEu(WO₄)₂ red phosphor could be effectively improved by using low-cost bionic doping of Li⁺ and SO₄ ²⁻.

The non-isothermal crystallization dynamic behavior and mechanism of plasma sprayed Fe₄₈Cr₁₅Mo₁₄C₁₅B₆Y₂ coating were thoroughly studied. The phase transition and crystallization kinetics of the coating were elaborately investigated by differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The findings reveal that the characteristic temperatures of the coating shift to an elevated temperature at a higher heating rate and the crystallization processes are thermally activated. The 3-rd step of crystallization processes is more susceptible to the continuously increased heating rate while the onset crystallization reaction is less sensitive to the continuously enhanced heating rate. Fe₂₃(C, B)₆ phase is inclined to precipitate than other crystal phases due to the substantial pre-generation of α-Fe. The onset nucleation and growth of α-Fe crystals is tough due to a higher onset apparent activation energy. Meanwhile, the transformation from Fe₂₃(C, B)₆ to FeB is harder in comparison with the precipitation of other crystals. The most parts of the three crystallization processes are dominated by three-dimensional diffusion model due to the fact that most values of local Avrami exponent are higher than 2.5.

Flexible PANI-Polyethersulfone (PES) fibers were fabricated using the wet-spinning technique. PANI particles were uniformly distributed within the matrix and micropores formed by the phase separation of PES, which prevented PANI particles aggregation and facilitated the formation of continuous ion transport channels. The experimental results reveals that the electrochemical performance of the fiber electrode material is optimal when the concentration of PES in the spinning solution is 15wt%. The assembled supercapacitor exhibits a commendable specific area capacitance of 162.75 mF·cm⁻² at a current density of 0.5 mA·cm⁻² and achieves an energy density of 14.47 mWh·cm⁻² at a power density of 321.69 mW·cm⁻². The capacitor retains 98.1% of its capacitance after 1 000 bending cycles. Therefore, the prepared fibers have good electrochemical properties and flexibility, and this simple and efficient preparation method is promising for the scalable production of flexible electrodes.

A copper-red and silver-white metallic glaze of R₂O-RO-Al₂O₃-SiO₂-P₂O₅ system was synthesized by adjusting the firing temperature and glaze components. The coloration mechanism of the metallic glaze was revealed via investigation of the microstructure of the glaze. Our research reveals that the metallic glaze with different colors is mainly due to the amount of Fe₂O₃. The metallic glaze shows a silver-white luster due to a structural color of α-Fe₂O₃ crystals with a good orientation when the sample contains 0.093 9 mol of Fe₂O₃, maintaining temperatures at 1 150 °C for 0.5 h. The metallic glaze is copper-red which is dominated by the coupling of chemical and structural color of α-Fe₂O₃ crystals when the sample contains 0.078 3 mol of Fe₂O₃. After testing the amount of SiO₂, we find that 4.049 9 mol is the optimal amount to form the ceramic network, and 0.27 mol AlPO₄ is the best amount to promote phase separation.

To investigate the influences of different admixtures on the drying shrinkage of polymer mortar in a metakaolin base, the experiments of VAE (vinyl acetate ethylene copolymer), APAM (anionic polyacrylamide) and CPAM (cationic polyacrylamide) on the drying shrinkage properties of geopolymer mortar were designed under normal temperature curing conditions. An SP-175 mortar shrinkage dilatometer was introduced to measure the dry shrinkage of geopolymer mortar. Meanwhile, the drying shrinkage properties of geopolymer mortar are exhibited by the parameters of water loss rate, drying shrinkage rate, drying shrinkage strain and drying shrinkage coefficient. The experimental data are further fitted to obtain the prediction model of dry shrinkage of geopolymer mortar, which can better reflect the relationship between dry shrinkage rate and time. Finally, the experimental results demonstrate that the dry shrinkage of geopolymer mortar can be significantly increased by adding 4% VAE admixture, meanwhile under the condition that the polymer film formed by VAE reaction can strengthen and toughen the mortar. 2.5% APAM admixture and 1.5% CPAM admixture can enhance the dry shrinkage performance of geopolymer mortar in a certain range.

FeP/FeO was prepared on carbon cloth (CC) via hydrothermal method, heat treatment in air, and phosphorization in argon. FeP/FeO/CC presents a porous and loose morphology which is conducive to the exposure of active sites and the transfer of reactants. FeP/FeO/CC requires the low overpotentials of 257 and 117 mV (vs. reversible hydrogen electrode (RHE)) to achieve the current density of 10 mA·cm⁻² for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline KOH solution, respectively. The small Tafel slope values of 36.1 mV·dec⁻¹ (for OER) and 96.2 mV·dec⁻¹ (for HER) indicate that FeP/FeO/CC exhibits the fast electrocatalytic reactive kinetics for OER and HER. In particular, the reaction kinetics of FeP/FeO/CC accelerated with the progress of HER. The charge-transfer resistance (R _ct) of FeP/FeO/CC is only 11 Ω. Excellent bifunctional electrocatalytic performances of FeP/FeO/CC should be attributed to the porous morphology and the lower charge-transfer resistance.

High entropy carbides (HECds) are multi-component carbides consisting of transition metal carbides. HECds are generally composed of five or more metal cations of the equal or near-equal substances, obtaining a single crystal structure. HECds have great potentials for future applications due to excellent mechanical, antioxidant and thermal properties. Due to their complex crystal structures and lattice distortion, computer simulations are widely used to efficiently associate the properties of HECds with the corresponding microstructures. In response to the development of HECds, this article provides an overview of the basic design, preparation process and properties of HECds.

Mechanical as well as durability properties are pivotal for any type of concrete which gets adversely affected due to cracks that may form due to loading beyond its capacity. Concrete has the intrinsic property to heal itself to some extent but not fully as the passive form of autogenous healing plays an inferior role for a complete repair of a cementitious material. The self-healing capabilities can be enhanced by adding chemical admixtures, polymers, and bacteria strains induced calcium carbonate precipitation, etc. In this paper, the advancements in the development and performance of self-healing concrete using chemical admixtures, polymers, and bacteria strains are reviewed. This systematic review includes the available experimental tests and methodologies investigating self-healing efficiency over the last decade. Further, this review focussed on self-healing materials, the ideology, and opinions of those in the construction field on the direction of self-healing concrete for future applications. It is yet not possible to predict the most appropriate technique, however, a generalized opinion about the effectiveness of the different approaches has been illustrated.

To investigate the freeze-thaw (F-T) damages and failure characteristics of rock mass with arc-shaped joints in cold regions, three types of cement mortar specimens with different central angles and prefabricated arc-shaped flaws are subjected to uniaxial compressive tests under different F-T cycles. Experimental observations show that the uniaxial compressive strength of specimens are significantly influenced by F-T cycles and their failure modes are mainly affected by the central angle a of the prefabricated flaws. Unlike the specimens with a central angle of 60°, the specimens with a central angle of 120° and 180° have greater curvature of flaws, so tensile cracks occur in the arc-top area of their prefabricated flaws. According to experimental images observed by environmental scanning electron microscope (ESEM), as the number of F-T cycles increases, the deterioration effect of the specimen becomes more obvious, which is specifically reflected in the increase of the mass loss, peak stress loss, and damage variables as a power function, and the peak strain decreases as a quadratic polynomial. According to numerical results using two-dimensional particle flow code (PFC2D), it is found that F-T cycles cause more damage to the specimen in the early stages than in the later ones. The area of the concentrated compressive stress zone in the middle is decreased due to the increased number of F-T cycles, while the area of the surrounding tensile-shear stress zone is increased. The models appear different failure modes due to the release of concentrated stress in different tensile-shear zones.

To investigate the impact of limestone powder on the chloride ion concentration coefficient of cement pastes, various techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and mercury-porosimetry (MIP) were employed in this paper. The findings demonstrate that the creation of Friedel’s salt is inversely associated with the addition of limestone powder, that is, Friedel’s salt production is lessened by adding more limestone powder, however, the coefficient of chloride ion concentration initially decreased and then increased again, as does the porosity, and most likely the pore size as well. The specific surface area of limestone powder has increased, and the content of Friedel’s salt increased first and then decreased. However, the shifting trend of Friedel’s salt and chloride ion concentration coefficient is in direct opposition, and the pore structure was therefore significantly enhanced. The results of this study offer robust theoretical backing for the inclusion of limestone powder in concrete and provide a positive assessment of its potential applications.

An exquisite mesostructure model was presented to predict the effective elastic modulus of concrete, in which concrete is realized as a four-phase composite material consisting of coarse aggregates, mortar matrix, interfacial transition zone (ITZ), and initial defects. With the three-dimensional (3D) finite element (FE) simulation, the highly heterogeneous composite elastic behavior of concrete was modeled, and the predicted results were compared with theoretical estimations for validation. Monte Carlo (MC) simulations were performed with the proposed mesostructure model to investigate the various factors of initial defects influencing the elastic modulus of concrete, such as the shape and concentration (pore volume fraction or crack density) of microspores and microcracks. It is found that the effective elastic modulus of concrete decreases with the increase of initial defects concentration, while the distribution and shape characteristics also exert certain influences due to the stress concentration caused by irregular inclusion shape.

We conducted a series tests on surface layers of plateau concrete at the ages of 180 and 540 days, including the most superficial cement paste, the 5 mm thick surface mortar, and the 50 mm thick surface concrete. Thermogravimetry and nitrogen absorption porosimetry on cement past, mercury intrusion porosimetry on mortar, and microhardness test on interface transition zone between mortar and coarse aggregate were conducted to evaluate the hydration degree and characterize the micro-structure. Whilst, tests for the rebound strength, abrasion resistance, and chloride ion impenetrability of concrete were conducted to assess the macroperformance. The experimental results show that, affected by the harsh plateau climate, outward surfaces have lower hydration degrees and worse pore structure than inward surfaces. As the hydration of concrete surface is ongoing after the age of 180 days, both the micro-structure and the macro-performance are continuously improved. In the long-term, either the orientation or the depth towards surface does not significantly affect concrete performance. Surface carbonation brings positive effects on mechanical properties but negative effects on the durability. Additionally, standard test result of chloride ion impenetrability is found significantly affected by the atmospheric pressure. For a same batch of concrete, charge passed in plateau regions is obviously lower than that in common regions.

The prediction model for mechanical properties of RAC was established through the Bayesian optimization-based Gaussian process regression (BO-GPR) method, where the input variables in BO-GPR model depend on the mix ratio of concrete. Then the compressive strength prediction model, the material cost, and environmental factors were simultaneously considered as objectives, while a multi-objective gray wolf optimization algorithm was developed for finding the optimal mix ratio. A total of 730 RAC datasets were used for training and testing the predication model, while the optimal design method for mix ratio was verified through RAC experiments. The experimental results show that the predicted, testing, and expected compressive strengths are nearly consistent, illustrating the effectiveness of the proposed method.

To solve the problems of high rebound rate and strength reversion of shotcrete, a non-fluorine and non-alkaline liquid flash setting admixture (FSN) with low rebound and high early strength was synthesized under 60–65 °C water bath environment through orthogonal test design and taking setting time and compressive strength as indicators. The experimental results show that the optimum mass ratio of FSN is aluminum sulfate: diethanolamine:triethanolamine: pseudo-boehmite: lithium carbonate: water=57%: 8%: 0.05%: 2%: 2%: 31%. When FSN is added with 7% of the mass of portland cement, the cement paste can be initially set in 3 min and finally set in 5 min. The compressive strength of mortar is 1.2 MPa at 6 h, 18.0 MPa at 1 d, and more than 100% at 28 days; The microscopic analysis shows that the rapid release of Li⁺, NH⁴⁺, and CO₃ ²⁻ ions by FSN in the paste solution effectively shortens the induction period of high C₃S content in Portland cement, directly forms early coagulation AFt crystals in FSN and CH dominated by Al₂(SO₄)₃, and forms a large number of C-S-H gels in the later stage, so that the cement can quickly coagulate and harden, and the strength in the later stage is not retracted.

Cement and resin were designed as mixed cementitious materials to study the smart aggregate(SA) of smart concrete. Carbon fiber(CF) and surfactant were taken into consideration to adjust the mechanical and electrical properties of smart aggregate(SA) in this issue. The experimental results indicate that the flexibility and mechanical properties of SA can be improved by using such mixed cementitious materials. It is shows that, although the compressive strength and flexural strength can be enhanced effectively by using resin and CF, the electrical conductivity decreases significantly, which is because the water molecules are difficult to penetrate through the mixture materials so the hydration reaction of cement can not fully carry out. However, the electrical conductivity can be improved by adding the surfactant, and the strength and mechanical electrical properties can be adjusted effectively by the surfactant.

This study aimed to investigate the performance evolution characteristics of concrete under permafrost ambient temperatures and to explore methods to mitigate the thermal perturbation by concrete on the permafrost environment. A program was designed to investigate the properties of various concretes at three curing conditions. The compressive strength development pattern of each group was evaluated and the concrete’s performance was characterized by compressive strength damage degree, hydration temperature and SEM analysis in a low temperature environment. The experimental results show that the incorporation of fly ash alone or incombination with other admixtures in concrete under low-temperature curing does not deteriorate its microstructure, and at the same time, it can slow down the hydration rate of cement and significantly reduce the exothermic heat of hydration of concrete. These findings are expected to provide valuable references for the proportioning design of concrete in permafrost environments.

A simplex centroid design method was employed to design the gradation of recycled coarse aggregate. The bulk density was measured while the specific surface area and average excess paste thickness were calculated with different gradations. The fluidity, dynamic yield stress, static yield stress, printed width, printed inclination, compressive strength and ultrasonic wave velocity of 3D printed recycled aggregate concrete (3DPRAC) were further studied. The experimental results demonstrate that, with the increase of small-sized aggregate (4.75–7 mm) content, the bulk density initially increases and then decreases, and the specific surface area gradually increases. The average excess paste thickness fluctuates with both bulk density and specific surface area. The workability of 3DPRAC is closely related to the average excess paste thickness. With an increase in average paste thickness, there is a gradual decrease in dynamic yield stress, static yield stress and printed inclination, accompanied by an increase in fluidity and printed width. The mechanical performance of 3DPRAC closely correlates with the bulk density. With an increase in the bulk density, there is an increase in the ultrasonic wave velocity, accompanied by a slight increase in the compressive strength and a significant decrease in the anisotropic coefficient. Furthermore, an index for buildability failure of 3DPRAC based on the average excess paste thickness is proposed.

A WTi-Al₂O₃ cermet-based solar selective absorber was prepared to investigate the atomic diffusion induced spectral selectivity degeneration. The as-deposited coating exhibits superior absorptance (0.934) and low thermal emittance (0.098), as well as excellent thermal stability with a selectivity of 0.900/0.07 even after annealing at 923 K for 400 h in Ar ambient. However, the multilayer coating failed after being subjected to annealing at 923 K for 400 h in an air environment, as indicated by a decrease in solar absorptance to 0.912 and an increase in thermal emittance to 0.634. The microstructure characterizations reveal that the annealed coating exhibits a columnar morphology along the vertical direction of the substrate. The presence of abundant grain boundaries in the multilayer coating promotes the outward diffusion of Cr and Mn atoms in the stainless-steel substrate. The Mn atoms, in particular, possess the capability to migrate towards the surface of the coating and undergo an oxidation reaction with oxygen, facilitating the formation of a thick Mn₂O₃ layer. The roughness of the coating surface was significantly increased in this case, adversely affecting solar absorptance due to amplified sunlight reflection. In addition, the rocketing of thermal emittance is attributed to the destabilization of W infrared reflective layer during the annealing. These findings highlight the importance of considering the outward diffusion of Mn and Cr elements in the stainless-steel substrate when optimizing solar selective absorbers.

We employed a melt ultrasonic treatment near the liquidus to prepare a high-thermal-conductivity Al-4Si-2Ni-0.8Fe-0.4Mg alloy. The influences of various ultrasonic powers on its microstructure, mechanical properties, and thermal conductivity were investigated. It is shown that near-liquidus ultrasonication significantly refines the alloy grains and eutectic structure, synergistically improving the alloy’s mechanical properties and thermal conductivity. Specifically, the grain size decreased by 84.5% from 941.4 to 186.2 µm. Increasing the ultrasonic power improved the thermal conductivity of the alloy slightly and significantly enhanced its mechanical properties. At an ultrasonic power of 2 100 W, the tensile strength, yield strength, elongation rate, and thermal conductivity were 216 MPa, 142 MPa, 6.3%, and 169 W/(m·k), respectively.

In order to improve the sealing surface performance of gray cast iron gas gate valves and achieve precise molding control of the cladding layer, as well as to reveal the influence of laser cladding process parameters on the morphology and structure of the cladding layer, we prepared the 316L coating on HT 200 by using Design-Expert software central composite design (CCD) based on response surface analysis. We built a regression prediction model and analyzed the ANOVA with the inspection results. With a target cladding layer width of 3.5 mm and height of 1.3 mm, the process parameters were optimized to obtain the best combination of process parameters. The microstructure, phases, and hardness variations of the cladding layer from experiments with optimal parameters were analyzed by the metallographic microscope, confocal microscope, and microhardness instrument. The experimental results indicate that laser power has a significant impact on the cladding layer width, followed by powder feed rate; scan speed has a significant impact on the cladding layer height, followed by powder feed rate. The HT200 substrate and 316L can metallurgically bond well, and the cladding layer structure consists of dendritic crystals, columnar crystals, and equiaxed crystals in sequence. The optimal process parameter combination satisfying the morphology requirements is laser power (A) of 1 993 W, scan speed (B) of 8.949 mm/s, powder feed rate (C) of 1.408 r/min, with a maximum hardness of 1564.3 HV0.5, significantly higher than the hardness of the HT200 substrate.

SiC particles were added to the Mg97Zn1Y2 alloy to improve its mechanical properties and damping properties. The microstructure, mechanical properties, and strain amplitude dependence of high-damping and high-strength SiC/Mg97Zn1Y2 magnesium matrix composites were analyzed. The strain amplitude-dependent damping of SiC/Mg97Zn1Y2 composites and the effect of SiC on this property were discussed herein. In anelastic damping, the strain amplitude-dependent damping curves of the composites were mainly divided into two sections, dominated by the G-L model. When the strain amplitude reaches a certain value, the dislocation motion inside the matrix becomes complicated. Moreover, the damping of the material could not be explained using the G-L model, and a new damping model related to microplastic deformation was proposed. In the anelastic damping stage, with the increase in the amount of the added SiC particles, the damping performance first increases and then decreases. Moreover, the damping value of the composite material is larger than that of the matrix alloy. In the microplastic deformation stage, the damping properties of the composites and matrix alloys considerably increase with the strain amplitude.

Magnetron sputtering deposition with regulated Cu target power was used for depositing Cucontaining high-entropy alloy nitride (Cu-(HEA)N) films on TC4 titanium alloy substrates. The microscopic morphologies, surface compositions, and thicknesses of the films were characterized using SEM+EDS; the anti-corrosion, wear resistance and antibacterial properties of the films in simulated seawater were investigated. The experimental results show that all four Cu-(HEA)N films are uniformly dense and contained nanoparticles. The film with Cu doping come into contact with oxygen in the air to form cuprous oxide. The corrosion resistance of the (HEA)N film without Cu doping on titanium alloy is better than the films with Cu doping. The Cu-(HEA) N film with Cu target power of 16 W shows the best wear resistance and antibacterial performance, which is attributed to the fact that Cu can reduce the coefficient of friction and exacerbate corrosion, and the formation of cuprous oxide has antibacterial properties. The findings of this study provide insights for engineering applications of TC4 in the marine field.

In order to clarify the effect of rare earth Gd on the microstructure evolution and deformation behavior of 7075 aluminum alloy during hot compression, uniaxial compression tests of Al-Zn-Mg-Cu-0.5%Gd were conducted at strain rates of 0.001, 0.01, 0.1, and 1 s⁻¹ with the temperatures ranging from 350 to 450 °C. The microstructural evolution during deformation was characterized using optical microscopy and electron backscatter diffraction (EBSD) techniques. The experimental results indicate that the addition of the rare earth element Gd significantly increases the peak flow stress and thermal activation energy of the alloy. Due to the pinning effect of rare earth phases, dislocation movement is hindered, leading to an increased level of work hardening in the alloy. However, the dynamic recrystallization of the alloy is complicated. At a high Z (Zener-Hollomon parameter) values, recrystallization occurs in the form of DDRX (Discontinuous Dynamic Recrystallization), making it easier to nucleate at grain boundaries. As the Z value decreases gradually, the recrystallization mechanism transitions from discontinuous dynamic recrystallization (DDRX) to continuous dynamic recrystallization (CDRX). At a low Z values with the strain rate of 0.001 s⁻¹, the inhibitory effect of rare earths weakens, resulting in a comparable recrystallization ratio between Al-Zn-Mg-Cu-Gd alloy and 7075 aluminum alloy. Moreover, the average grain size of the aluminum alloy with Gd addition is only half that of 7075 aluminum. The addition of Gd provides Orowan and substructure strengthening for the alloy, which greatly improves the work-hardening of the alloy compared with 7075 aluminum alloy and improves the strength of the alloy.

By using high-alumina fly ash as raw material, a process was proposed for activating the fly ash with Na₂CO₃ calcination and extracting aluminum from activated clinker with sulfuric acid leaching. The feasibility of roasting process of activated fly ash by Na₂CO₃ was discussed based on thermodynamic analysis. The experimental results showed that Na₂CO₃ gradually reactes with mullite over 700 K to produce NaAlSiO₄. The optimal process conditions for the activation stage are: a material ratio of 1:1 between sodium carbonate and fly ash, a calcination temperature of 900 °C, and a calcination time of 2.5 hours. Under these conditions, the leaching rate of aluminum is 90.3%. By comparing the SEM and XRD analysis of raw and clinker materials, it could be concluded that the mullite phase of fly ash is almost completely destroyed and transformed into sodium aluminosilicate with good acid solubility.

We developed a new preparation to protect probiotic cells from adverse environmental conditions and improve their livability, which is called Lactobacillus casei-Sodium alginate-Chitosan (LSC). The LSC was prepared by mixing probiotics with sodium alginate-chitosan sol. The preparation contained complex calcium ions, which were released in the acidic environment of gastric juice, thus crosslinking to form in-situ gel. Different proportions of sodium alginate-chitosan were prepared to add to simulate gastrointestinal fluid to get the best ratio. The optimal ratio of LSC preparation was compared with traditional gel microspheres to observe the survival effect of probiotics in gastrointestinal fluid environment. Compared with sodium alginate sol, the porosity of sodium alginate-chitosan sol is lower, which is beneficial to the protection of probiotics. When the ratio of chitosan to sodium alginate is 1.5: 1.5 (w/v), the protective effect is the best. The protective ability of LSC is 64 times that of traditional microspheres, and it has the potential of synergistic anti-tumor. A probiotic preparation with simple preparation process and better protection effect compared with traditional microspheres was prepared, which has joint anti-tumor potential.

We synthesized photo-responsive carboxymethyl chitosan (CMC-MA) via free radical polymerization and utilized nanoclay laponite (LAP) as an inorganic crosslinking agent to develop an injectable and 3D-printable CMC-MA/LAP hydrogel. We determined the optimal ratio of 2.5 w/v% CMC-MA/7.5 w/v% LAP based on injection molding, compression modulus, swelling properties, rheological properties, and 3D printing properties of the hydrogel system. In-vitro cytocompatibility experiments showed that both CMC-MA and CMC-MA/LAP hydrogel had no inhibitory effect on cell proliferation and can promote cell growth when cultured on the surface of the hydrogel matrix. Moreover, the hydrogel containing LAP particles significantly facilitated cell adhesion (>60%) compared with the hydrogel without LAP (20%). Our findings demonstrate that the CMC-MA/LAP hydrogel has great potential for tissue repair in neural tissue engineering.