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In the quest to produce high-strength steel, the preparation technology for vanadium–nitrogen alloy (VN) was refined through thermodynamic analysis, employing it as an additive to enhance the strength and hardness of microalloyed steel. Changes in the Gibbs free energies associated with the reactions between vanadium oxides and carbon in a nitrogen atmosphere were meticulously calculated and examined. This study explored the effects of the carbon to V2O5 ratio, the nitrogen to V2O5 ratio, and the pressure on the production of VN and CO at various temperatures. The results indicate that the productivity of VN is highest under conditions of approximately 1000 °C, a C:N2:V2O5 ratio of 10:8:1, and a pressure of 1 bar. Under these conditions, VN constitutes approximately 70% of solid products, with a conversion rate of around 67.92%. CO accounts for approximately 38.17% of the exhaust gas, resulting in a yield of approximately 45.28%. The CO generated can be utilized as fuel in the production of iron in blast furnaces, providing an opportunity for secondary use of resources. [ABSTRACT FROM AUTHOR]

Gas prevention and control have always been the focus of coal mine safety. The pore structure characteristics and gas adsorption characteristics of coal seams are the key factors affecting gas adsorption and diffusion in coal seams. Lvjiatuo Mine has the characteristics of a high gas content when it enters deep mining. In order to clarify the influence of the pore-fracture structure characteristics of main coal seams in the research area on coal seam gas adsorption and diffusion, and to study the differences in gas adsorption and diffusion ability in different coal seams, low-temperature nitrogen adsorption (LT-N2GA), high-pressure mercury intrusion (MIP) and computerized tomography (μ-CT) were used as characterization methods, and methane isothermal adsorption experiments were carried out to systematically study the pore structure characteristics of five groups of coal samples, and the pore-fracture structure characteristics and gas adsorption characteristics of each main coal seam were obtained. The results show that: (1) in the LT-N2GA experiment, the adsorption–desorption curves of all coal samples are of type III, and mainly develop cone-shaped pores or wedge-shaped semi-closed pores, with an average pore size of 1.84~4.84 nm, a total pore volume of 0.0010~0.0023 mL/g, a total specific surface area of 0.16~0.24 m2/g, and a fractal dimension D1 of 1.39~1.87 and D2 of 2.44~2.60. The micropores of L12 are more developed, and the mesopores and macropores of L9 are more developed. (2) In the MIP experiment, the porosity of coal samples is 3.79~6.94%. The porosity of L9 is the highest, the macropore ratio is the highest, and the gas diffusion ability is also the strongest. (3) In the μ-CT experiment, the porosity of L8-2 and L12 is 12.12% and 10.41%, the connectivity is 51.22% and 61.59%, and the Df is 2.39 and 2.30, respectively. The fracture of L12 is more developed, the connectivity is better, and the heterogeneity of the pore of L8-2 is higher. (4) In the isothermal adsorption experiment of methane, the gas adsorption capacity basically increases with the increase in the buried depth of the coal seam, and the gas adsorption capacity of the No.12 coal seam is the highest. Based on the pore-fracture structure characteristics and gas adsorption characteristics of the main coal seams in the research area, the gas outburst risk of each coal seam is ranked as follows: No.12 coal seam > No.8 coal seam > No.7 coal seam > No.9 coal seam. The experimental results provide important help for researching the structural characteristics of coal seam pore fractures and preventing gas outbursts during deep coal seam mining. [ABSTRACT FROM AUTHOR]

LiNi0.5Co0.2Mn0.3O2 is extensively researched as one of the most widely used commercially materials for Li‐ion batteries at present. However, the poor high‐voltage performance (≥4.3 V) with low reversible capacity limits its replacement for LiCoO2 in high‐end digital field. Herein, three‐in‐one modification, Na‐doping and Al2O3@Li3BO3 dual‐coating simultaneously, is explored for single‐crystalline LiNi0.5Co0.2Mn0.3O2 (N‐NCM@AB), which exhibits excellent high‐voltage performance. N‐NCM@AB displays a discharge‐specific capacity of 201.8 mAh g−1 at 0.2 C with a high upper voltage of 4.6 V and maintains 158.9 mAh g−1 discharge capacity at 1 C over 200 cycles with the corresponding capacity retention of 87.8%. Remarkably, the N‐NCM@AB ||graphite pouch‐type full cell retains 81.2% of its initial capacity with high working voltage of 4.4 V over 1600 cycles. More importantly, the fundamental understandings of three‐in‐one modification on surface morphology, crystal structure, and phase transformation of N‐NCM@AB are clearly revealed. The Na+ doped into the Li–O slab can enhance the bond energy, stabilize the crystal structure, and facilitate Li+ transport. Additionally, the interior surface layer of Li+‐ions conductor Li3BO3 relieves the charge transfer resistance with surface coating, whereas the outer surface Al2O3 coating layer is beneficial for reducing the active materials loss and alleviating the electrode/electrolyte parasite reaction. This three‐in‐one strategy provides a reference for the further research on the performance attenuation mechanism of NCM, paving a new avenue to boost the high‐voltage performance of NCM cathode in Li‐ion batteries. [ABSTRACT FROM AUTHOR]