To deeply explore the knowledge production status and development logic in the field of risk communication for public health emergencies in China，this study systematically sorts out 234 core literatures from CNKI using bibliometrics and content analysis. First，the knowledge production trend is summarized through quantitative statistics; second，the Citespace software is used to construct a visual knowledge map of the main subjects and carriers of knowledge production and core issues，analyzing the current situation of knowledge production; finally，the content logic and process logic of knowledge production are sorted out through content analysis of the literature. The results show that the current knowledge production of risk communication for public health emergencies in China is driven by both "push" and "pull" factors. There is an obvious trend of interdisciplinary crossover，the content system of knowledge production is taking shape; and the methods of knowledge production are characterized by diversity.

In order to study the influence of section size change on noise propagation in long space of coal mine roadway，the simulation method was used to study the noise propagation in the roadway，and to analyze the influence of the changes of section area size，section shape and section area mutation rate on the noise propagation in the roadway of coal mine roadway. The results showed that: the section area size，section shape and section area mutation rate in coal mine tunneling would affect the propagation of noise in the tunnel，when the noise source power and frequency were the same，the attenuation of the sound pressure level increased with the increase of the section area of the roadway. For a given section area (18 m²)，when the section shape was different，the attenuation of the sound pressure level was also different，and there would be an obvious acoustic focusing effect when the section shape was arch-shaped. When the cross-section area changed abruptly，the distribution of sound pressure level in the roadway would change，in which the change of cross-section area from large to small was not conducive to noise attenuation，and the change of cross-section area from small to large only affected the sound field after the abrupt change，and the overall sound pressure level in the roadway is not significant. The field test and numerical simulation results of noise attenuation in the tunnel were basically consistent，which verified the reliability of the model and simulation results.

In order to avoid the spontaneous combustion of residual coal from the regenerated roof during coal mining，the characteristics of interior fluid field were clarified，and the dynamic law of coal spontaneous combustion hazardous zone was explored. Taking the spontaneous combustion features of residual coal from the regenerated roof of a mine in Shandong province as an example，the numerical simulation method was used to simulate and compare the air leakage characteristics of goaf and regenerated roof under different air volume. Subsequently，based on the structural characteristics of the regenerated roof，the scope of coal spontaneous combustion hazardous zone was determined by adopting a new method of projection superposition judgment with oxygen concentration and air leakage speed as comprehensive indexes. The results of the study show that the oxygen mass fraction of goaf decreases gradually when the depth is smaller than 60 m，while it's no longer affected by the air volume when the depth exceeds 60 m. The oxidation zone is asymmetrically distributed，forming a "triangle" hollow area at the end of the return airway. The air leakage and backflow occurs in the range of 20-40 m in dip direction of goaf，whereas the air leakage velocity of regenerated roof presents a U-shaped symmetrical distribution. The change features of coal spontaneous combustion hazardous zone in the goaf resemble those of the oxidation zone. In contrast，the coal spontaneous combustion hazardous zone in the regenerated roof is mainly distributed near the middle of the intake airway and the inner part of the front middle of the return airway，and the area of coal spontaneous combustion hazardous zone gradually expands and extends towards the tail with the increase in air volume.

Equipment and facility failures were the primary cause of safety accidents in public transportation systems. In order to better quantify and enhance the safety resilience of systems，CN-FRAM operational safety resilience measurement model，integrating CN and FRAM，were proposed. System resilience was defined as the ratio of system performance loss to performance baseline under perturbations. Firstly，based on the composition and functional nodes of the equipment and facility system，a CN was established. Secondly，the FRAM model was embedded into the CN to expand nodes and connections，constructing the CN-FRAM model. Then，based on the CN-FRAM resilience measurement model，the aggregation of functional changes between system components was analyzed，and when quantifying system resilience，the overall efficiency of the network and the degree of coupling between components were considered comprehensively. Finally，using the metro signal system in Nanjing as an example，the feasibility and effectiveness of the method were validated. The results show that the model can quantify the resilience of the system throughout the disruption-recovery process，calculate the impact of failures on the system，and maximize resilience values as the objective，demonstrating resilience performance under different repair strategies，thereby providing a basis for determining the optimal recovery sequence. Compared with existing methods，the optimal recovery strategies identified by this method can significantly reduce the overall performance loss caused by failures，thus enhancing system resilience.

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 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.

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 reduce gas explosion accidents during the production，transportation and storage of combustible gases in industrial sites，square pipes of 200 mm×200 mm×35 m and round pipes of 90 mm diameter and 10 m length were independently constructed. Under the same initial conditions，the explosion test of methane/air premixed gas with volume fraction of 9.5% was carried out，and it was studied with pressure and flame sensors. The results show that the evolution process of the wave system in two kinds of pipes with different scales and cross sections is the same. After ignition，the flame changes from layer to turbulent flow，and the acceleration of flame leads to the compression wave chasing each other，finally forming a strong shock wave. The changing trend of flame speed in the two long straight pipes is the same，and they both experience the process of acceleration-deceleration-re-acceleration-re-deceleration，with the maximum flame speed in the square tube and round tube reaching 69 and 35.7 m/s respectively. After the first compression wave reflects off the wall，the pressure rises to 117% and 114%. When the reflected wave is coupled with the flame front，the flame speed in the large-scale pipeline is reduced to 73%，and that in the small pipeline is reduced to 93%. Under the same volume fraction，the maximum overpressure values of the first compression wave in the two long straight spaces are similar，which are about 65.45 and 67.09 kPa.

In order to reduce the fire safety risk of urban buildings and improve the ability of building units to resist fire accidents，the influencing factors of fire safety were identified from three aspects: building fire protection design，building fire protection facilities and fire safety management，and the assessment index system of fire safety of urban buildings was constructed. A combined weighting-TOPSIS model of structural entropy and information entropy was applied to assess the fire safety risk of each district and each type of building in the cities. The model was validated with 262 buildings in 5 major areas of X city in western China. Finally，fire safety index and comprehensive ranking were obtained，and then the existing weak points of urban buildings fire protection were clarified. The results indicate that comprehensive evaluation order of fire safety is commercial complexes > primary and secondary schools > heritage buildings > high-rise buildings，city center > north of the city > east of the city > west of the city > south of the city. The fire safety risk of urban fringe counties and high-rises need to be paid attention to. The assessment results calculated with this model are consistent with the current situation.