Molecular dynamics simulations were used to investigate the temperature effect in the microstructural evolution of nanocrystalline Al-Mg-Si alloy under different pressures and velocities. A deformation mechanism map is proposed through quantitative characterization of the microstructural evolution. This map provides a “phase diagram” illustrating the elastic-plastic transition, stacking faults (SFs), grain refinement, and shear layer formation under different temperatures and loads. Changes in temperature alter SFs motion and microstructural integrity. SFs appear in the form of single trace line (300 K) and multiple parallel lines (77 K), respectively. Compared to 300 K, the rotation and slip motion of grains in the sample are restricted at 77 K, making it difficult for the microstructure to rearrange. Under external loading, the degree of grain refinement is greater at 77 K (up to 13.2% refinement) compared to the refinement at 300 K (maximum ∼8.3%). This leads to the generation of a greater number of grain boundaries (GBs) and SFs. Additionally, there is a significant variation in the special GBs (represented by 23) with a relatively high overall content. A sudden drop in integrity occurs at a pressure of 10⁵ atm. And the deformation at the highest velocity recovers to almost the same low level as at the lowest velocity.

Twisted bilayer transition metal dichalcogenides including MoS₂ have attracted great interest due to their unique Moiré superlattice induced electronic flat bands. High-quality twisted bilayer TMDs with uniform Moiré potentials are essential for the discovery of strong correlation effects, unconventional superconductivity, and quantum anomalous Hall effect. However, the synthesis of large-area high-quality twisted bilayer MoS₂ (tBMoS₂) using chemical vapor deposition (CVD) is still absent, which needs to overcome the formation energy barrier for nonstable twist bilayers. Here, we demonstrate a novel CVD approach with local airflow perturbation for growing tBMoS₂ by a heterosite nucleation strategy, which enables the nucleation of the second layer at the different site from the first layer nucleation site with arbitrary twist angles. Furthermore, the accurate determination of interlayer twist angles in tBMoS₂ is crucial for studying structure-physical properties relationship. We quantitatively compare the measurement accuracy between a geometrical method and TEM selected area electron diffractions (SAED), in which the measured angles from TEM-SAED shows much smaller angle errors. Finally, Raman spectra show the interlayer coupling can be tuned by the twist angles. Our study opens an avenue for the controllable growth of tBMoS₂ for both fundamental research and practical applications.

Hot extrusion, solution, and artificial aging were conducted on the designed Mg-Zn-Al-Sn-Mn alloy. The microstructure evolution and corrosion behaviors of the alloy were studied. A multimodal structure composing of both deformed and recrystallized grains is observed in as-extruded alloy, while a fully recrystallized grain structure forms in solutionized alloy. Moreover, the majority of second phases dissolved into Mg matrix during solution. In aged state, the highest hardness of HV84 was realized after 24 h aging, and the densely distributed τ-Mg₃₂(Al, Zn)₄₉ was the main strengthening precipitates. With increasing aging time, some amounts of precipitate had evidently coarsened by the dissolution of smaller ones, leading to a bimodal distribution of large (150–200 nm) and fine (∼50 nm) precipitates in over-aging state. The solutionized alloy owned the optimal corrosion resistance because of its large grain size and dissolution of second phase. However, the corrosion resistance was degraded again by aging treatment attributed to a mass of τ-Mg₃₂(Al, Zn)₄₉. Moreover, the intergranular corrosion took the place of pitting and filiform corrosion, and became a dominant corrosion mechanism in aged alloy.

Despite the high theoretical capacity as the anode material adopted in lithium-ion batteries, SnO₂ materials undergo rapid capacity fading and low-rate performance due to the significant volume change and poor conductivity. This research proposes a straightforward approach to prepare hollow structured SnO₂ spheres based on the N-dopped C coating layer (HS-SnO₂@N_xC) to overcome these problems. The structural and elemental characterizations were performed, and the cycling performance of HS-SnO₂@N_xC was systematically investigated. The presence of a hollow void in the HS-SnO₂@N_xC material allows for adaptation to volume changes during the charging and discharging process. Additionally, the outer framework of N_xC strengthens the structural integrity of the spheres and facilitates the transfer of electrons and charges. These factors significantly improve the rate performance of the anode material. Owing to these advantages, HS-SnO₂@N_xC electrodes delivered a stable capacity of 610 mA·h/g at 0.25C after 750 cycles. Meanwhile, the great reversible rate performance of 76.7% was attained after a superior rate performance of 425 mA·h/g at 5C (1C=800 mA/g).

Friction stir lap welding (FSLW) was used to weld as-cast SiC_p/ZL101 composite plate and ZL101 alloy plate to prepare a new brake disc material, and the as-cast SiC_p/ZL101 composite plate was modified by friction stir processing (FSP). The microstructure and friction and wear properties of the as-cast SiC_p/ZL101 composites after FSP were studied to evaluate the braking performance of the new brake disc material. After FSP, the pores in the SiC_p/ZL101 composites are eliminated, and the average size of SiC particles is reduced from 12.8 pm to 3.9 pm. The grains are obviously refined from 8.2 pm to 3.2 pm. The friction coefficient of the as-cast SiC_p/ZL101 composites increases firstly and then decreases in the initial stage, and then tends to be stable after 500 s, but the friction coefficient fluctuates greatly. After FSP, the fluctuation ranges of the microhardness and friction coefficient are all reduced, the friction process is stable, and the wear extent is equivalent to about 45% of that of the as-cast SiC_p/ZL101 composites. The as-cast SiC_p/ZL101 composites are dominated by abrasive wear, showing a fatigue wear characteristic. The FSPed SiC_p/ZL101 composites are dominated by oxidation wear, and the size of wear debris is relatively small.

Materials derived from metal-organic frameworks (MOFs) have found extensive applications in various antimicrobial uses in recent years. Transition metals have undergone extensive research due to their exceptional efficiency, low toxicity, and affordability. In this paper, three typical transition metal MOFs, copper (Cu-MOF), iron (Fe-MOF) and zirconium (Zr-MOF), are characterized in detail microscopically and their antimicrobial properties are systematically compared. The synthesis and microstructure of MOFs were validated using various instruments, such as SEM and PXRD. The investigation into bacterial (E. coli) test results revealed that the bactericidal effects of Cu-MOF, Fe-MOF, and Zr-MOF followed a descending order. Furthermore, the solution containing Cu-MOF displayed zero colonies in the same environment, demonstrating a 100% lethality against E. coli, a result significantly higher than the other two groups. Nevertheless, Fe-MOF and Zr-MOF exhibited an increase in antimicrobial properties of 2.47% and 73.56%, respectively, after exposure to light, both of which still demonstrated outstanding bactericidal effects.

Potassium-ion batteries (PIBs) are regarded as one of the alternatives to lithium-ion batteries due to the vast potassium reserves in nature and low potential of K⁺/K. Therefore, in this work, we successfully synthesized porous nitrogen-doped FeP/C nanofibers (P-FeP/C-N NFs), a novel electrode material for PIBs, via simple electrospinning and subsequent calcination treatment, in which polyacrylonitrile (PAN) and polymethylmethacrylate (PMMA) are used as nitrogen source and pore-forming agent, respectively. The introduction of nitrogen improves the conductivity of the material, and the formation of a porous structure increases the specific surface area. More importantly, when the P-FeP/C-N NFs were used as electrode for potassium ion batteries, they exhibit excellent electrochemical performance. The P-FeP/C-N NFs electrode exhibits a discharge capacity of 274.2 mA·h/g at 100 mA/g after 250 cycles and 171.3 mA·h/g at 1000 mA/g after 300 cycles. Even at 5000 mA/g, it displays a high discharge capacity of 150.1 mA·h/g. These findings indicate that the P-FeP/C-N NFs are expected to be a candidate of anode materials for potassium ion batteries.

Researchers focus on the magnetic properties of Fe-80Ni alloy (79 wt%–81 wt% Ni). The cleanliness of the alloy influences its magnetic properties. This paper investigated the impact of cerium on the cleanliness and magnetic properties of Fe-80Ni alloy. The mass fraction of cerium ranged from 0 to 0.025%. The O and S contents can be reduced to 0.0008% and 0.0012% respectively when the content of Ce is 0.025%, and the number of inclusions is almost halved compared to blank samples without Ce addition. In addition, the primary inclusions were modified to Ce-containing inclusions (Ce₂O₃, Ce₂O₂S, CeS, and CeO₂) with Ce addition. Compared to the primary aluminosilicate inclusions, the Ce-containing inclusions are resistant to extrusion, elongation, or breakage, while their distribution is more dispersed, resulting in less detrimental effects on the magnetic properties. The magnetic properties of Fe-80Ni alloy are improved with the addition of cerium compared to those without cerium. The coercivity of alloys reduced from 3.67 Oe to 3.58 Oe, while the maximum magnetic susceptibility (χ_max) increased from 0.0173 to 0.0222.

In this study, we investigated the difference and mechanism of the degradation of Rhodamine B by hexagonal natural pyrrhotite (HNP, Fe_0.93S) and monoclinic natural pyrrhotite (MNP, Fe_0.85S) activating peroxydisulfate (PDS). The results show that the degradation efficiency of MNP/PDS system was higher than that of HNP/PDS system under both acidic and weak alkaline conditions, and both decreased with the increase of pH. The better degradation efficiency was related to the higher dissolved iron concentration of MNP/PDS system and the stronger surface reactivity of MNP. Among them, the surface reactivity was recognized as dominant, namely, the degradation reaction mainly occurred on and near the surface of natural pyrrhotite (NP). The strong surface reactivity of MNP was first reflected in the higher Zeta potential, so that the electrostatic attraction between MNP and PDS was greater. This meant that PDS was more easily activated by MNP. Secondly, the MNP possessed higher surface oxidation degree and higher corrosion current density, which contributed to the heterogeneous activation of PDS by Fe(II) and the reduction of Fe(III) to Fe(II) (or Fe³⁺ to Fe²⁺) by surface reductive sulfur species (such as S²⁻ and S₂²⁻) as electron donors. Moreover, the loose oxide layer on the MNP surface was easy to fall off during the degradation process, and new surface reaction sites are re-exposed.

With the advancement of mining operations, xanthate as an essential flotation reagent is unavoidably released into natural water bodies through flotation effluent. To protect the surrounding environment of mines, Au-BiOBr-TiO₂ (AuBT) ternary composites were constructed and utilized as an optimal photocatalyst in the degradation process of xanthates. AuBT with high purity was prepared by the integrated techniques of hydrothermal, water bath precipitation, and photodeposition. BiOBr nanosheets and Au nanoparticles were uniformly distributed on the surface of TiO₂ particles in the composites. In simulated mineral flotation effluents, AuBT showed excellent degradation performance in the catalytic oxidation of 20 mg/L xanthate under visible light irradiation, achieving 95.2% removal rate in 20 min. The experiments and characterization results revealed that the dual-loading strategy to construct AuBT photocatalysts effectively decreased the band gap and broadened the photoresponse range of pristine TiO₂, which was significant for the improvement of the photocatalytic activity. DFT calculations demonstrated that partial electrons were transferred around the sodium ethyl xanthate (SEX) molecule and the accumulated charge contributed to the oxidation process. Experimental results of free radical scavenging indicate that the main active species in the reaction system are photogenerated holes (h⁺), followed by superoxide radicals (•O₂). This work indicates that AuBT composites can be used as an efficient photocatalyst to completely degrade various types of xanthates under visible light, which exhibits great potential in flotation wastewater treatment.

Core discing often occurs during drilling under deep in-situ stress environment. To determine its formation mechanism in sandstone under deep in-situ stress environment, PFC2D was used to study the crack distribution and energy evolution during drilling under different in-situ stress, and specific in-situ stress conditions prone to core discing were obtained. An independently developed testing system was utilized to verify the stress conditions required for core discing in laboratory settings, and to analyze the relationship between the failure and fracture surface morphology characteristics of the core and in-situ stress. The results show that the higher the in-situ stress, the more tensile cracks will be generated in the rock during drilling, especially at the hole wall and the root of the core. The cracks in the core develop from the outside surface inward. Higher in-situ stress levels also result in greater energy transformation, leading to fracture of the rock. The formation of core discing requires specific stress conditions. Core discing occurs at the root of the core when the radial stress (σ_r) is the maximum principal stress at a constant value of 45 MPa and the axial stress (σ_a) is either 25 MPa or 30 MPa. When the difference between σ_r and σ_a increases or the drilling depth increases, the disc thickness decreases, resulting in smoother fracture surfaces and smaller fractal dimensions and thus more pronounced core discing. This study can provide technical and data support for scientifically elucidating the formation mechanism of core discing under deep in-situ stress conditions.

To study the influence of lithology on the directional propagation law of rock type-I cracks, a simple crack directional propagation device was used to conduct loading tests on three rock types. The acoustic emission (AE) and displacement field characteristics during crack directional propagation were analyzed, and the propagation mechanism of type-I cracks was discussed. The results indicate that the post-peak load curve of white sandstone showed a gradually decreasing trend, while marble and grey sandstone showed a steep decreasing trend. The AE evolution during crack propagation can be divided into four stages: quiet, slowly increasing, booming, and decreasing. For white sandstone, the duration of the first three stages was short, and the decreasing stage was long. However, the opposite trend was observed for the other types. The crack propagation process includes three stages based on the evolution law of the horizontal displacement field: elastic deformation, microcrack nucleation and coalescence, and crack initiation and propagation. The white sandstone enters the microcrack nucleation and coalescence stage earlier than marble and grey sandstone. The length of the fracture process zone of white sandstone was larger than those of marble and grey sandstone; thus, its crack directional propagation rate and stability were lower.

The quantitative determination of crack stress thresholds is of great significance to comprehend the deformation and failure of rock. In the study, we proposed a new model to estimate the crack closure and crack damage stress thresholds based on axial plastic strain. Then we compared the stress thresholds calculated by the proposed method with that by existing methods to validate the accuracy of our method. Finally, we discussed the effect of the error of elastic modulus on estimated stress thresholds. The results show that the crack closure and crack damage stresses predicted by the proposed method are very close to that by other methods. This indicates the proposed method can accurately identify the crack closure and crack damage stresses of rock materials. Moreover, the proposed method greatly reduces the dependence on elastic parameter and obtains the stress thresholds of crack closure and crack damage objectively. Based on the results, we developed a detailed flow chart for the proposed method to minimize the effect of elastic modulus.

Tension failure of deep surrounding rock is a very common failure mode, which is closely related to the couple of static pre-stress and impact load. Thus, the dynamic tensile strength of pretension stressed Brazilian disc (BD) specimens subjected to the impact load was measured at the couple different pretension levels and loading rates with the modified split Hopkinson pressure bar (SHPB) system. Six groups of Linyi sandstone BD specimen were impacted with the loading rates from 400 to 1200 GPa/s under the pretension of 0, 0.48, 1.44, 2.39, 3.45 and 4.30 MPa. The test results reveal the dynamic tensile strength has a very significant linear positive correlation with the loading rate, wherein increases gradually with the loading rate increase, reflecting the obvious rate dependency. The dynamic tensile strength decreased significantly with pretension stress level increase at the same loading rate, showing an obvious dynamic tensile strength weakening effect. Besides, the mechanism of the dynamic tensile strength weakening effect is summarized, wherein the pretension stress level dominates and determines the dynamic tensile strength weakening level, and the impact load induces the appearance of the strength weakening effect.

Anchoring support using bolts and cables works together with rock masses to form an integrated anchoring system and jointly resists the energy released by dynamic disasters. The strength and elongation of traditional support are often insufficient, causing anchoring system failure when withstanding dynamic disasters. Constant resistance energy-absorbing (CREA) material is a new type of support material with high strength and large elongation. To understand the mechanical properties of this new material and its anchoring system, we carried out static tensile and dynamic impact tests on the CREA anchoring material. Subsequently, the SHPB impact tests were carried out on rocks anchored by CREA, MG335, and MG500 anchoring materials. The deformation and failure characteristics of anchored rocks under high-speed impact were studied. Compared with MG335 and MG500 anchored rocks, the peak stress of the CREA anchored rock is increased by 42.2% and 63.9%, and the absorbed energy is increased by 42.0% and 63.2%. The CREA supporting technology can enhance the bearing capacity and energy-absorbing capacity of the anchored rock under dynamic impacts. Finally, we propose engineering suggestions to anchored rocks using the CREA supporting technology under strong disturbance and carry out a field application in a deep burst-prone coal mine.

Microwave heating technology is currently a prominent area of research in the field of composites curing due to its advantages, including selective heating, energy saving and high efficiency. However, the uneven distribution of electric field inside the cavity leads to asynchronous heating of composite components. This, in turn, results in severe deformation and curing defects, posing a major challenge that hinders the widespread industrial application of microwave process. In this paper, by combining nonlinear electromagnetic constitutive equations and power density functions, the correlation between the uniformity of electric field and the temperature distribution in composite components during microwave heating was elucidated. Finite element simulations were employed to investigate the influence of various regulation methods, such as the setting of generators, the introduction of mode stirrers, and the relative movement of loading platform, on the uniformity of electric field distribution. An experimental apparatus for regulating microwave heating uniformity was independently designed and developed, and a series of experiments were conducted to validate the accuracy of the simulation analysis and investigate the temperature variation in microwave-cured components under different regulation modes. Finally, an analysis was performed on the influence of temperature distribution during the curing process on the performance of composites.

Soft sensor plays a key role in the safe operation of industrial processes and product quality control. In industrial processes, the switching of operation conditions may lead to distribution discrepancy and dimension inconsistency between the training data (source domain) and testing data (target domain), leading to the soft sensor model mismatch problem. In addition, the data may be incomplete because of sensor transmission failure, where the missing values may influence the accuracy of the soft sensor. This article introduces a partial transfer learning network (PTL-Net) for soft sensors under different operation conditions with missing data. First, the imputation and soft sensor modules are constructed for source domain data, where a compactness loss is designed to induce feature aggregation to alleviate the influence of abnormal features mapped from missing data. Then a partial transfer strategy is proposed to reduce the distribution discrepancy between the source and target data. Furthermore, the proposed strategy selects the common components between two domains for partial knowledge transfer rather than inheriting all the parameters directly, which can overcome the model mismatch problem. The effectiveness of PTL-Net is verified under the nuclear dataset and the three-phase flow process.

Elastohydrodynamic lubrication (EHL) plays a crucial role in reducing surface deformation and friction, leading to improved stability and reliability of gear transmissions. A model is proposed to investigate the complex relationship between EHL and time-varying mesh stiffness (TVMS) in spur gears, aiming to solve the TVMS under EHL. The proposed model incorporates EHL, slice coupling, extended tooth contact (ETC), gear body coupling flexibility, and modified tooth stiffness. To enhance accuracy, the tooth stiffness is adjusted by eliminating redundant energy calculations. Furthermore, an iterative relationship between slice coupling and deformation compatibility equations (DCE) is derived. The proposed model is validated by MASTA and reference. The effects of EHL and slice coupling on meshing characteristics are analyzed. The findings reveal that the TVMS of gears with crowning increases significantly after considering slice coupling and the load distribution shifts towards the middle of the tooth side.

Unsaturated soils are extensively encountered in nature and engineering practice. Understanding the hydromechanical coupling effects in the infiltration process of an unsaturated porous medium is of considerable interest to the geotechnical and hydrological community. In this paper, a nonlinear, fully hydromechanical coupling model that controls unsaturated flow in a deformable porous medium is presented. It relies on a finite element (FE) solver to calculate the hydromechanical responses of deformable unsaturated soils subjected to transient flow. The model is performed under unsteady rainfall conditions and surface ponding conditions, showcasing its ability to predict the infiltration process. Additionally, an analytical solution and a ponded infiltration test are used as references. Finally, the factors that affect unsaturated flow are discussed based on a series of parametric simulations. The results further indicate that the couplings cannot be neglected and are affected to varying degrees by different parameters.

For the stability and failure pattern analysis of bimslopes, a novel second-order cone programming optimized micropolar continuum finite element method (mpcFEM-SOCP) incorporating the micropolar Mohr-Coulomb (MC) model is developed. Based on two bimslopes, the effectiveness and superiority of the present method is examined. Numerical analyses disclose that the presence of rock blocks “intruding” the potential slip surface may increase the ultimate bearing capacity of the rigid footing and contribute to the stability of bimslopes. Compared to the second-order cone programming optimized classical continuum finite element method (FEM-SOCP), it is interesting to note that mpcFEM-SOCP may reveal different failure mechanisms evidently from those predicted by FEM-SOCP in some cases. For the bimslope with square-cluster rock blocks, it is observed by FEM-SOCP and mpcFEM-SOCP that the presence of scattered rock blocks complicates the failure patterns of bimslopes. Compared to the generalized limit equilibrium method in the Pybimstab package assuming a single slip surface, FEM-SOCP and mpcFEM-SOCP may produce finger-pattern slip surfaces, and particularly the width of slip surfaces in matrix soil may be adequately modeled by the internal characteristic length /_c bridging the particle characteristics of matrix soil and the macroscopic strain localization behavior.

To investigate the infiltration characteristics of carbonaceous mudstone soil-rock mixtures under the effect of rainfall infiltration, model tests considering rock contents and rainfall infiltration angles were carried out, and the various patterns of volumetric water content and matrix suction at each elevation within the sample were obtained. The VAN-GENUCHTEN model was used to fit the test results, helping to obatain the soil-water characteristic curves of carbonaceous mudstone soil-rock mixtures. The research results show that the volumetric water content of the carbonaceous mudstone soil-rock mixture was in a gradient trend, with the water content increasing from top to bottom and reaching a stable level, and the bottom sample saturated to the top. The permeability coefficient of the carbonaceous mudstone soil-rock mixture demonstrated a trend of first decreasing and then increasing with the increase of rock content. The rise of rainfall infiltration angle effectively inhibited the reduction of matrix suction inside the sample during the rainfall process. During the drainage process, the water content at each elevation within the sample showed an exponential function with the changing pattern of drainage time. Furthermore, the rock content and the rainfall infiltration angle affect the sample’s particle loss.

The bearing behaviour of larger-diameter piles significantly influences the performance of subway station construction using the pile foundation pile-beam-arch (PBA) approach. This paper proposes a numerical method combined with back analysis optimized by the clonal selection algorithm (CSA) to construct an equivalent top-loading (ETL) curve using the field O-cell test data. The test data are used to verify the proposed method. The behaviour of large-diameter piles is analysed based on the test data. In the specific conditions of this study, the optimal positioning of the self-equilibrium point is determined to be within a range of 0.10 to 0.25 times the pile length from the bottom of the pile. In addition, the effects of pile diameter, length, and buried depth on the empirical factor, self-equilibrium factor, and ultimate bearing capacity of the original pile are investigated. The influence of the loading direction on the side friction resistance is minimal. The ratio of the total skin friction to the ultimate bearing capacity increase as the pile length and buried depth, but decrease when the pile diameter increases.

The use of recycled building demolition wastes (BDWs) as unbound aggregate materials (UAMs) is one of the resource-conserving, economical, and eco-friendly alternatives for pavement base/subbase construction. The mesoscale strength and crushing properties of individual coarse aggregate particles significantly affect macroscopic strength and deformation behavior of such recycled UAMs. In this paper, the crushing strength and compressive deformation of recycled BDW aggregates of different sizes and constituents were systematically studied from single particle crush tests and oedometer tests, respectively. The test results demonstrate that the single-particle crushing strength exhibited significant size effect and the peak crushing stress values decreased with increasing particle size for the same constituent type of recycled BDW particles. The stress-strain relationship obtained from oedometer tests was well described by the hyperbolic function. Under the same vertical stress level, the vertical strain and the yield stress values of the oedometer specimens increased and decreased gradually with increasing particle size, respectively. Finally, the relative breakage index B_r was used to quantify particle breakage for each particle size range under different vertical stress levels. The ultimate crushing state of each particle size range was obtained from the limit of each predictive equation of the relative breakage index B_r.