MXene and cotton-derived biochar were prepared by modified acid etching and high-temperature carbonization, respectively. Based on their characterization with SEM and XRD, a suitable mass ratio of MXene to the cotton-derived biochar for modification purpose was determined. The electrochemical properties of the materials were further explored by performing charge-discharge and cyclic voltammetry tests, and using electrochemical impedance spectroscopy. It is shown that the MXene delivers an initial discharge specific capacity of 434.3 mAh/g at a current density of 0.1 A/g. A composite with MXene and cotton-derived biochar in a mass ratio of 1∶3 can deliver an initial discharge specific capacity of 1 486.60 mAh/g at 0.1 A/g, exhibiting excellent cycling performance, rate capability and electrical conductivity, which can provide a reference for application of MXene in lithium-ion batteries.

Effects of elements Ti and N on the precipitation behavior of TiN inclusions during the solidification of Timicroalloyed high-strength steel were studied by thermodynamic calculation and microscopic analysis. Thermodynamic calculation results indicate that the precipitation of TiN inclusions is unavoidable at the solidification front, but can be delayed by reducing the value of w(N)₀×w(Ti)₀. The final size of TiN inclusions is mainly affected by the initial nitrogen content in molten steel, and TiN inclusions can be smaller by reducing the initial nitrogen content. Microscopic analysis shows that with the contents (mass fraction) of Ti and N decreasing from 0.12% and 0.005% to 0.08% and 0.003%, respectively, the number density and average size of TiN inclusions can be decreased by 27.1% and 50.2%, which also confirms the thermodynamic calculation results.

The fundamental principles of stereolithography (SLA), digital light processing (DLP), and two-photon polymerization (TPP) in photo-curing technique for ceramic were reviewed. Based on systematical introduction and analysis of the research status, application fields of SLA, DLP, and TPP technologies, as well as the existing challenges, a comprehensive review was provided of ceramic slurries and their performance optimization, photo-curing mechanisms, and subsequent debinding and sintering processes. Finally, prospects for obtaining ceramic slurries with high performance, finished products with superior mechanical properties and translating research outcomes into practical applications were discussed. Furthermore, several recommendations were proposed, including increasing the types of ceramic slurries, accelerating the development of composite ceramic materials, and making more efforts in research of large-size ceramic components.

Three types of carbon-coated silicon monoxide (SiO) materials were synthesized with different carbon sources and coating methods, and then their physicochemical properties and electrochemical performance were analyzed. A uniform and dense carbon film on the surface of material can be obtained by using a gaseous carbon source for vapor-phase coating. While a solid carbon source for liquid-phase coating leads to an uneven and loose film on the surface. With a combination of these two coating methods, the obtained carbon film on the surface can exhibit characteristics of two methods, including inner porous layer and outer dense layer. Electrochemical testing shows that with the combined coating method, the synthesized carbon-coated material delivers a specific capacity of 1 688.45 mAh/g, presenting the first charge-discharge efficiency of 76.13% and the capacity retention rate of 79.6% after 100 charge-discharge cycles.

The effect of vacuum hot-pressing sintering time on phase composition, microstructure, and densification of Al-30%Sc aluminum alloy were investigated using X-ray diffraction, scanning electron microscopy and electron backscatter diffraction. Results show that after a sintering process at 630 ℃ under 30 MPa, the prepared alloy samples exhibit good uniformity. As sintering time prolongs, the content of Al₃Sc phase in the alloy decreases but the content of Al₂Sc phase increases, and the density and grain size remain virtually unchanged.

Marmatite was calcined and then used as photocatalyst to degrade organic dye methylene blue (MB) under ultraviolet (UV) light irradiation. The degradation mechanism of this photocatalyst was investigated by using UV-Visible diffuse reflectance spectroscopy (UV-Vis DRS) and performing free radical capture experiments. It is found that the marmatite calcined at 660 ℃ exhibits a great photocatalytic property, with the degradation rate of MB up to 98.46% within 240 min. In the calcined marmatite products, the ternary heterojunction is more conducive to the effective separation of photogenerated charge carriers than the binary heterojunction, thus leading to an improved photocatalytic performance.

As for the current situation of component segregation and significant brittleness tendency in laser cladded coating of austenitic stainless steel, an austenitic cladded coating was prepared by adopting laser cladding technology, and then effects of preheating and annealing treatment on the microstructure, mechanical properties and service performance (corrosion and corrosive wear) of the cladded coating and heat-affected zone (HAZ) were investigated. The results show that the phase composition of the austenitic coating after preheating or annealing process remains predominantly austenitic, exhibiting only grain growth and a preferential orientation shift towards the (111) crystal plane. Both the cladded coating and HAZ have decreased hardness, but significant improvement in the tensile strength and elongation. This is because that the heat treatment not only reduces the intergranular fracture tendency of the cladded coating but also improves the ductile fracture tendency of the HAZ. Furthermore, preheating or annealing process can enhance the corrosion resistance and wear resistance of the austenitic cladded coating, among which annealing process can bring a significant effect. These improvements are attributed to the synergistic effect of reduced component segregation and enhanced plasticity and toughness in both cladded coating and HAZ.

The 3104 aluminum alloy treated by hot tandem mills at different finish rolling temperature (FRT) was taken as the samples in the experiment to investigate the effect of FRT on its microstructure and texture evolution during the subsequent cold rolling and intermediate annealing processes. It is found that as the FRT for the 3104 aluminum alloy sample rises, the hot-rolled sheet presents highly recrystallization level, with increased volume fraction of Cube texture and decreased volume fractions of Brass, S and Copper textures. Furthermore, as FRT rises, the average grain size of the intermediate annealed sheet increases, and also the volume fraction of Cube texture in the cold-rolled sheet before intermediate annealing process increases, which is unfavorable for the formation of a strong Cube texture after annealing. As a result, the volume fraction of Cube texture in the final cold-rolled sheet decreases.

In order to address the poor presplit blasting effect on the final slope of the Yulong Copper Mine in Xizang Autonomous Region, the engineering applicable ranges of parameters such as decoupling coefficient, borehole diameter, linear charge density and hole spacing were calculated in consideration of the combined effects of explosion-generated gases and air shock waves, and the presplit blasting parameters were also optimized by performing orthogonal experiment. The results indicate that with a borehole diameter of 120 mm, a linear charge density of 800-1 000 g/m and a hole spacing of 0.9 m, the half-borehole rate after blasting exceeds 95%, the unevenness between adjacent holes is much less than ±5 cm, and the slope gradient deviation is less than ±2°, forming a continuous and regular presplit surface. This confirms the engineering applicability of the theoretically calculated parameter ranges.

A new type of discontinuous mining system for deep-sea polymetallic nodules was proposed, consisting of collecting seafloor ore, conveying to buffer by flexible hose, and high-speed lifting of buffer. Then, the design and key equipment selection were carried out for the collecting system, flexible hose conveyance system and buffer lifting system for comprehensively lifting 100 t/h of ores at water depth of 5 200 m in the Minmetals' Contract Area. Furthermore, flexible hose configuration and load characteristics, as well as cable load dynamics during buffer lifting were all analyzed by hydrodynamic simulation. It is shown that with the flexible hose equipped with 18 buoyancy blocks, minimum bending radius of 1.6 m and a maximum tension of 4.98 kN, the whole mining system can satisfy requirements for the minimum bending radius and safe load capacity. During high-speed lifting of buffer, the cable can have the safety factor of comprehensive stress up to 5.22-6.03, exceeding the safety factor stated in national standard. These findings validate the reliability of this new type of deep-sea discontinuous mining system.