A foreign copper sulfide concentrate from slag processing was treated by adopting heated sulfuric acid leaching with trivalent iron compound as an oxidant for recovering copper therein. The effects of oxidant dosage, leaching temperature, leaching time, initial concentration of sulfuric acid and liquid-solid ratio on the leaching rate of copper from copper sulfide concentrate were investigated. The results show that with the proper condition, including the oxidant of hematite at an amount of 0.2 g/g ore, leaching temperature of 85 ℃, leaching time of 6 h, liquid-solid ratio at 5∶1, and sulfuric acid with initial concentration of 200 g/L, the copper leaching rate can reach 97.96%. A verification test with different oxidants shows that hematite and magnetite present good oxidability in acid leaching system, leading to the copper in those copper sulfide concentrate leached out at a medium temperature. Also, the higher the purity of trivalent iron compounds, the better the oxidative leaching effect of copper.

To address the problems of low conductivity and poor cycling performance of silicon oxide as negative electrode material, polyacrylamide (PAM) was adopted as a carbon source for the first carbon coating, and the methane-acetylene mixture was used as a gas-phase carbon source for the second coating by chemical vapor deposition to prepare nitrogen-containing double-layer carbon-coated silicon oxide anode materials (SiO_x@ DC-N). Compared with pure gas-phase coated (SiO_x@ GC) and pure liquid-phase coated (SiO_x@ LC) silicon oxide anode material, SiO_x@ DC-N exhibits excellent rate performance and cycling stability, showing that the specific capacity is 850.1 mAh/g at a current density of 4C (1C=1 500 mA/g). The 18650 cylindrical batteries prepared by using a mixed graphite in a ratio of 5∶95 can have a capacity retention rate of 92.70% after 700 cycles of charging and discharging at a current density of 1C.

Experiments were carried out for alumina ceramics with rotary ultrasonic-assisted and ordinary milling-grinding processes respectively by using a small diameter electroplated grinding wheel. The variation of grinding force with ultrasonic power, linear speed of grinding wheel, feed rate and grinding depth during milling-grinding of alumina ceramics was analyzed. The results show that with ultrasonic power from 0 W up to 90 W and other parameters keeping constant, the grinding force is in decline and the surface topography is significantly improved. As the linear speed of grinding wheel increases, while the feed rate and grinding depth decrease, the grinding force in both rotary ultrasonic-assisted and ordinary milling-grinding processes decreases. With the processing parameters in the tested range, the grinding force in rotary ultrasonic-assisted milling-grinding process is lower compared to the ordinary milling-grinding process. Besides, the maximum reduction in normal and tangential grinding force of rotary ultrasonic-assisted milling and grinding can reach 24.17% and 23.30% respectively.

The microstructure and mechanical properties of A356 aluminum alloy joints were studied after they were processed with technique of T6 heat treatment followed by friction stir welding (T6-FSW) and technique of friction stir welding followed by T6 heat treatment (FSW-T6) respectively. It is found that the nugget zone of T6-FSW joint is composed of dynamically recrystallized fine-grains, but the precipitates are dissolved or coarsened. The transverse tensile strength and elongation of T6-FSW joint are 214 MPa and 5.3% respectively, and an average hardness is 76HV_0.5. The tensile strength and elongation of the nugget zone are 236 MPa and 12.5% respectively, and the impact toughness of the joint is 12.10 J. Abnormal grain growth occurs in the nugget zone of FSW-T6 joint, where fine precipitates with high density are formed. The transverse tensile strength and elongation of FSW-T6 joint are 254 MPa and 8.5% respectively, and an average hardness is 96HV_0.5. The tensile strength and elongation of the nugget zone are 297 MPa and 7.0% respectively, and the impact toughness of the joint is 8.23 J.

To address the problems of low recognition accuracy and slow speed of current plate shape pattern recognition methods, a pattern recognition model for cold-rolled strip plate shape based on IHPO-KELM was proposed. Firstly, kernel extreme learning machine (KELM) network was adopted to reduce the number of initial parameters in the network and improve the accuracy and speed of plate shape recognition. Secondly, Levy flight mechanism was added to the improved position update formula for linear combination by using the population of the predator algorithm initialized based on Sine chaos mapping, so as to improve the accuracy of the predator (HPO) algorithm, as well as to address the problem of HPO easily falling into local precocity during the iteration process. Then, the improved predator algorithm was used to optimize the regularization and kernel parameters of the KELM network model, as well as improve the accuracy of plate shape recognition. Finally, the Matlab simulation results have verified that the IHPO-KELM algorithm has the advantages of simple network structure, high convergence speed, and high recognition accuracy. The recognition accuracy of IHPO-KELM algorithm in identifying the measured data of 900HC reversible cold rolling mill of a company is higher than the KELM recognition model optimized with sparrow algorithm (SSA-KELM) by 58.8%, indicating a good generalization ability of IHPO-KEM recognition model. This provides a new idea for efficient and intelligent recognition of plate shape defects.

With Pr₆O₁₁ and CeO₂ as additives, B₄C matrix composite materials were prepared at 2 200 ℃, 1 900 ℃, and 1 700 ℃ by adopting techniques of pressureless sintering, hot pressing sintering, and spark plasma sintering, respectively. The relative microstructure and mechanical properties were also studied. It is found that PrB₆ and CeB₆ formed in situ can fill the pores between B₄C grains, and improve the density of the composites. Compared with pressureless sintering and hot pressing sintering, the technique of spark plasma sintering can bring the prepared composites with higher density. The fracture toughness of B₄C-CeB₆ composites can be improved due to its high relative density, as well as the deflection, branching and bridging of cracks occuring along CeB₆, which extends the expansion path of cracks and reduces stress concentration. The B₄C-CeB₆ composite prepared by spark plasma sintering has good comprehensive mechanical properties, with the relative density, vickers hardness, bending strength and fracture toughness reaching 99.3%, 34.7 GPa, 451 MPa and 4.38 MPa·m^1/2, respectively.

The effects of low temperature tempering on the microstructure and mechanical properties of Q1100 ultra-high strength steel after pretreatment of normalizing and quenching were studied. The results show that tempered martensite were obtained after normalizing (890 ℃ × 40 min) + quenching (890 ℃ × 30 min) + tempering (185-320 ℃ × 90 min) processes. After tempering at different temperatures, all tested steels have their tensile strength higher than 1 360 MPa, yield strength higher than 1 200 MPa, hardness higher than 400HV3, elongation higher than 13%, and impact energy at -40 ℃ higher than 35.2 J. With the rising of tempering temperature, the tensile strength and hardness gradually decrease, the yield strength first increases and then decreases, the elongation after fracturing increases after an initial slight decrease, and the impact energy at -40 ℃ decreases followed by increase. At a tempering temperature of 230 ℃, the steel in the test has tensile strength of 1 445 MPa, yield strength of 1 238 MPa, hardness of 429HV3, plasticity of 13.8%, and toughness of 47.5 J, which all largely exceed the service standard of Q1100 ultra-high strength steel for construction machinery.

A basic polishing solution consisting of perchloric acid and methanol was optimized by adding citric acid and glycerol, and different kind of polishing solution was used for electropolishing of titanium nickel alloy wires. The surface morphology, corrosion resistance, and blood compatibility of untreated and polished wires were compared and studied. The results show that addition of citric acid and glycerol has a significant effect in corrosion inhibition and increases the controllability of the polishing process. With the optimized polishing solution, the surface of electropolished titanium nickel wire becomes flatter, with average roughness declined from 161.3 nm to 15.6 nm. The self-corrosion potential increases from -0.167 V to 0.045 V. The dissolved nickel content of phosphate buffer solution becomes lower, indicating the higher corrosion resistance. The hemolysis rate declines from 2.333% to 0.333%, and the number of adhesive platelet significantly decreases, thus the blood compatibility is enhanced.

The composition structure and operation process of mini seafloor crawler drill are briefly introduced. A multi-body dynamic model of mini seafloor crawler drill was established by using Recurdyn software. And then, a mechanical model was established for seafloor sediment based on an experimental study on mechanical properties of sediment soil. Dynamic simulation was also performed for the motion of mini crawler drill on seafloor. Results show that mini seafloor crawler drill runs on seafloor sediment with slight slippage and an elevation angle due to a certain sinking of seafloor sediment. It is found that the dynamic characteristics of mini seafloor crawler drill is significantly influenced by the mechanical properties of sediment (especially thin and soft sediment), and mini seafloor crawler drill running at a lower speed will bring greater influence to its dynamic characteristics.

With Sanguikou Lead Zinc Mine in the Inner Mongolia Autonomous Region taken for study, the influencing factors and parameter optimization for rock fragmentation by deep-hole cut blasting were explored by performing theoretical analysis, image processing and engineering tests. Firstly, in view of the problems of high fines generation rate and small fragment size on average, the factors influencing blasting fragmentation were tested and field data were collected. Also, image processing and analysis were performed for the muckpile in the test by using Split-Desktop 4.0 software. Then, the primary and secondary factors affecting blasting fragmentation were determined based on grey correlation analysis. Finally, an optimal scheme of blasting parameters was determined by using trend analysis based on actual situation of the site, and was then verified in the practical engineering test. The results show that the fines generation rate by the cut blasting in the mine is mainly affected by the delay time between rows and the borehole spacing, and the average fragment size is mainly affected by the borehole spacing and the number of rows for blasting. The optimized blasting parameters are finally determined as follows: borehole spacing of 1.2 m, row spacing of 1.5 m, burden of 0.8 m, 3 rows of boreholes, delay interval of 13 ms, 0 ms, 9 ms and 18 ms, respectively, between 4 holes, and a delay interval of 42 ms between rows. With the above-mentioned parameters, the blasting can result in the fines generation rate down by 27.19% and the average fragment size up by 62.89%.