Thermochemical sulfate reduction (TSR) is one of the main contributors to the formation of hydrogen sulfide (H2S) in coal seam strata. Four reaction systems (coal, coal+water, coal+water and MgSO4, and coal+water and MgSO4 and AlCl3) were selected and simulated from 250°C to 600°C with eight temperature steps using a high-temperature and high-pressure reaction device, and the evolution characteristics of the gaseous products of hydrocarbons (methane, C2-5) and nonhydrocarbon gases (CO2, H2, and H2S) were studied. Thermal simulation experiments showed that the TSR led to the reduction of heavy hydrocarbons, and the presence of salts accelerated the evolution of hydrocarbons; SO42-, Al3+, and Mg2+ had a certain promoting effect on the TSR, which increased the total amount of alkane gas, H2S, and CO2 production. Improving the salinity of the reaction system can promote the occurrence of TSR, and water plays a key role in hydrocarbon generation evolution and the TSR.

We investigate the femtosecond laser filamentation in nanoparticle colloidal solutions. Colloidal solutions of water doped with gold (Au), silver (Ag), copper (Cu), and calcium carbonate (CaCO3) nanospheres under different sizes and concentrations were experimentally studied. A cyan–red light path was visualized, and the generated supercontinuum spectra spanning from 400 nm to 950 nm were obtained. It was found that the energy losses and frequency-dependent scattering are necessary prerequisites for generating a colorful light path.

For the needs of practical teaching of safety engineering related majors, in order to have a clearer and more intuitive understanding of the structure of urban underground integrated pipe gallery and related knowledge of fire and explosion treatment, the construction of a virtual simulation experimental teaching platform for urban underground integrated pipe gallery fire and explosion has been carried out in-depth research. Through the construction of the platform, the highly realistic urban underground pipe gallery structure is reproduced virtually, so that students can carry out experiments in a virtual environment, and realize the experimental teaching such as the understanding of the structure of the underground integrated pipe gallery, the use of the inspection instruments in the pipe gallery, the analysis and disposal of the formation factors of the fire in the pipe gallery, cardiopulmonary resuscitation and hemostasis bandage. The experimental teaching practice shows that the experimental teaching method of immersion, guidance, heuristic and problem creation greatly stimulates students' interest in learning, enhances students' autonomous learning ability and learning efficiency, improves the experimental teaching effect, saves a lot of teaching experiment time and money, and completes the purpose of teaching.

A hydraulic fracture extension model was established, an extension criterion and an extension mode of hydraulic fracture were analyzed, and the theoretical prediction was compared with the practical results, a good agreement was observed. Furthermore, the direction of hydraulic fracture extension was also discussed, the results showed that the hydraulic fracture propagates from the cut to the bedding plane, forming a complex mixture of longitudinal and transverse fractures fracture network. The hydraulic fracture extension direction is influenced by its extension critical pressure and its extension pressure in the rock formation. Practice shows that hydraulic fracturing can effectively weaken the strength and integrity of the roof, so that the roof in the mining area can collapse in layers and stages. The present theoretical analysis can be used for reducing or eliminating the hazard of the hard roof to the working faces.