To investigate the features and causation factors of fire accidents in SRBE，118 fire accidents were studied using method of mathematical statistics. Firstly，accident features were mined in terms of the temporal and spatial attributes of accidents，the three elements of fire and the severity of injuries. Then，based on the improved HFACS-SRBE accident causation model，methods such as Chi-square test，OR and Cramer's V were used to analyze the correlations and their strength between the causal factors. The results show that 14:00-16:00 is the most prone to fire accidents and casualties. The main location of fire accidents is in the ship area，accounting for 33.90%. 59.19% of the ignition source comes from the ignition operation. Ratio of no injuries，slight and minor injuries，serious injuries and deaths is 61:54:3. Through the test of correlations and their strength，it is determined that 15 groups of adjacent level causal factors are correlated，and 26 complete accident causation chains are obtained. Covers communication and coordination→inappropriate operation plans→bad psychological state→decision-making errors is the accident causation chain with the greatest strength of correlation leading to the occurrence of fire accidents in ship repair and building enterprises.

In order to clarify the correlation of eVTOL risk factors，and explore their impact on risk prevention and control in the UAM ecosystem，complex network theory was used to establish a risk evolution model. Based on the UAV accident database at home and abroad and the statistics of general aviation accidents，combined with the operation characteristics of eVTOL in urban low-altitude scenes，35 types of risk factors and 10 types of dangerous events were identified from the perspective of human-machine-environment. Gephi software was used to construct the network model，and the key nodes were evaluated comprehensively by the node degree，proximity centrality，internode centrality and PageRank(PR) algorithm. The key edges were evaluated by the internode number，so as to determine the key risk propagation path. In order to reduce the system risk，the measures to reduce the chain breaking disaster were proposed，and the system safety after chain breaking control was measured by network efficiency index. The results show that there are strong correlations among the eVTOL risk factors in the UAM ecosystem，and there are eight key risk transmission chains. The system safety is improved by 4.74%，16.21% and 18.10% by blocking key human factors，key system technical failure factors and key intermediate dangerous events，respectively.

To enhance the risk prevention and control capabilities of hazardous chemical factories and support emergency decision-making in case of accidents，a multi-level deduction model for the disaster chain was proposed. Furthermore，three categories of key factors (such as thermal radiation，toxic gases，and overpressure) affecting hazardous chemical accidents were considered in the model. Based on the fluid diffusion model and Probit model，the fire probability and sequence simulation algorithm of hazardous chemicals container and the ignition time estimation algorithm of hazardous chemicals explosion were proposed，respectively. Then，the quantitative analysis of the combustion and explosion evolution process in hazardous chemical accidents was performed. For the case of a resin chemical production company in Guangdong province，a disaster chain caused by hazardous chemical leakage accidents was developed to analyze the evolution time and probability of each node. The results indicated that the proposed deduction model can effectively analyze the evolution process of the actual hazardous chemical disaster chain，predict the probability and time of accident nodes，and provide fundamental knowledge for the safety layout of hazardous chemical plants.

In order to solve the problems of easy water loss and poor dust suppression effect in coal seam water injection technology，a dust suppression method which can not only increase the water retention rate of coal seam but also improve the brittleness of coal seam was proposed. A gum-forming dust suppressant based on sodium alginate (SA) was developed. The effects of surfactant，viscosity and injection pressure on the gum-forming dust suppressant were tested by means of specific surface area test，nitrogen adsorption test，scanning electron microscope test and dust production rate test. The test results show that the surfactant is beneficial to the wetting of the coal seam，but has little effect on the dust suppression. The increase of the viscosity of the dust suppressant is conducive to water retention，which can increase the water retention time from 10 h to 30 h，but it will make it difficult for the material to enter the coal seam. The injection pressure has a great influence on the dust suppression effect of the dust suppressant. When the coal seam injection pressure is small，the dust suppressant is difficult to quickly penetrate into the internal pores of the coal. With the increase of pressure，the dust suppressant gradually penetrates into the coal pores. When the injection pressure rises to 3 MPa，the dust suppression effect no longer increases with the increase of pressure，and the dust production rate is reduced from 4% to 2.3%，which is relatively decreased by 50%，effectively reducing the dust production.

To better perform the experimental practical teaching and training of mining safety majors and cultivate first-class comprehensive top-notch talents in safety emergencies，a virtual simulation experimental teaching system for mine fire monitoring and prevention based on Unity3D was designed. Firstly，the simulation models were developed by 3ds Max，and then the overall framework of the experimental system for mine fire monitoring and prevention was constructed. Secondly，practical experimental trainings for human-machine interaction were conducted such as external fire monitoring and remote automatic control of disaster relief ventilation door emergency response，internal fire monitoring，and temperature-controlled cell coating chemical agent fire extinguishing emergency control. Finally，a comprehensive evaluation experimental evaluation system was proposed for assessment and evaluation. The results showed that the experimental system had the technical characteristics of immersion，interactivity，and conception of virtual reality，which created an underground three-dimensional virtual simulation scene and realistically displayed the evolution process of mine fires. For the experiments and practical training，the experimental system broke through the limitations of traditional models in terms of time，space，safety，and resources，providing self-directed learning and diverse evaluation methods.

In order to reduce the safety problems caused by leakage of hydrogen-blended natural gas during the distribution，based on fluid mechanics and porous media theory，a three-dimensional numerical model of leakage and diffusion of urban buried hydrogen-blended natural gas pipeline was established by Fluent software. The effects of hydrogen blending ratio，leakage aperture，pipeline pressure，pipeline buried depth and soil type on the leakage of hydrogen-blended natural gas and the vertical diffusion distance of the lower explosion limit of methane and hydrogen were analyzed. The results show that the larger the proportion of hydrogen blending，the smaller the leakage of hydrogen-blended natural gas，and the longer the time it takes for the methane explosion lower limit contour to diffuse to the surface，while the opposite is true for hydrogen. Secondly，the leakage amount is about twice as much as 5 mm when the leakage aperture is 10 mm. The leakage amount is about twice as much as 10 mm when the leakage aperture is 20 mm. The larger the leakage aperture，the shorter the time required for the lower explosion limit of methane and hydrogen to reach the surface. Thirdly，the greater the pipeline pressure，the greater the leakage of hydrogen-blended natural gas and the faster the diffusion speed，and the higher the risk coefficient. Besides，when the buried depth of the pipeline is 1.1m，the leakage is largest，followed by 1.4 m and 0.8 m. The shallower the buried depth，the shorter the time required for the lower explosion limit of methane and hydrogen to reach the surface. Finally，the soil type has an important influence on the leakage and diffusion of hydrogen-blended natural gas. When the soil type is silty sand，the leakage and diffusion rate of hydrogen-blended natural gas are the largest，followed by loam and finally clay.

To address the issues of allocation of emergency rescuers，emergency rescue equipment，and disaster locations in the early stage of emergency rescue under the background of large-scale geological disasters，as well as improve the efficiency and quality of emergency rescue，an emergency rescue allocation decision-making method was proposed based on the three-sided matching theory. Firstly，the selection process among the three parties of emergency rescue was presented as a three-sided matching issue. Then，the multi-attribute preference evaluation information of the matching three parties was standardized，and a multi-attribute comprehensive preference score matrix was proposed. Furthermore，a three-sided matching stable and satisfactory model in the early stage of emergency rescue was developed to maximize system stability and total preference utility. Finally，the performance and accuracy of the proposed model were validated against cases. The results indicated that the proposed model reached reasonable matching between rescuers，emergency rescue equipment，and disaster locations in emergency rescue scenarios due to considering the effects of various parties' preferences on resource allocation. Furthermore，it can contribute to reducing the deployment time of emergency rescue operations and improve emergency efficiency and quality.

In order to clarify inerting effect of liquid nitrogen on the thermal runaway explosion of a 280Ah energy storage lithium battery，based on experiment analysis of composition and explosion limit of battery thermal runaway gas，FLACS was used to simulate explosion overpressure of battery thermal runaway gas in a storage container. Standard experiments and real experiments were carried out to analyze inerting effect of liquid nitrogen on battery thermal runaway gas. Results show that thermal runaway gas explosion overpressure increases gradually with an increase of its volume. Ignition of more than 1.1 m³ of thermal runaway gas can cause serious consequences. A single 280 Ah lithium iron phosphate battery in 100% charged state，heating in a vacuum state，heating in a vacuum state can trigger thermal runaway of the battery and produce 134.6 L of thermal runaway gas with CO₂，H₂，CO，CH₄ and C₂H₄ as the main components. Thermal runaway gas is a flammable gas，and explosion limit range is between 8.5% and 45.5%. N₂ can effectively inert thermal runaway gas and significantly reduce the explosion limit range of thermal runaway gas. Limiting N₂ volume fraction is 84.7%. Spray 69 kg liquid nitrogen into a 35 m³ energy storage container to inert battery thermal runaway gas. When volume fraction of N2 is higher than limiting nitrogen volume fraction，battery thermal runaway gas can be effectively inerted，and effective protection time is 2 200 s.

To investigate the development trend of occupational health of coal miners and promote the implementation of occupational health protection in coal mines. Based on the knowledge graph analysis method，CiteSpace software was used to conduct the keyword clustering and emergence of coal miners' occupational health literature included in the core databases of China National Knowledge Infrastructure(CNKI) and Web of Science(WoS) in the past 20 years. The results indicated that coal miners' occupational health research topics were divided into occupational health，occupational hazard factors，and career-related diseases. Occupational-related diseases focused on behavioral and physical diseases，cardiovascular and cerebrovascular diseases metabolic diseases，and chronic non-specific respiratory diseases. Compared with occupational diseases，occupational-related diseases had the characteristics of 'multiple causes and one effect'，causing much more difficulty in diagnosis. Pneumoconiosis，hearing loss，psychological stress，and hypertension were the main factors threatening coal miners' health. Moreover，such health issues were associated with occupational exposure，and risk analysis and control were important strategies to deal with hazard factors. The emerging research hotspots were the cause and prevention of occupational-related diseases，and the multi-discipline research of occupational health，brain science，and intelligence.

In order to improve the accuracy of fire water cannon jet trajectory prediction and overcome the difficulty of traditional parabolic theory to describe the phenomenon that "when the initial velocity is constant，the range increases with the increase of jet flow"，first of all，the Euler method was used to establish a one-dimensional mass conservation equation along the trajectory of the water jet in the air，axial momentum conservation equations and the radial momentum conservation equations. Then，assuming that the axial velocity distribution of the water column and air column was in the shape of "bowler hat"，the established conservation equations were derived and analyzed，and the fire water cannon water jet trajectory calculation model was established. Finally，based on three conservation equations，the numerical computation process of the jet trajectory model was given and verified with the collected experimental data. The results show that the error of this model is less than 10%.