To improve the city's resilience in responding to public safety risks，an integrated theoretical model of "spatial resilience" for urban public safety was proposed，and an urban public safety resilience evaluation index system was developed from the perspective of residents' perceptions. The entropy weight method was used to evaluate the public safety resilience level for Nanjing comprehensively. The results indicated that the overall score of Nanjing's public safety resilience was 6.851 5，and there was a structural imbalance in the resilience construction for the ternary space. Furthermore，social space safety resilience was the highest，followed by information space safety resilience，and physical space safety resilience was the lowest. The unbalanced development of urban public safety space resilience can be attributed to several factors including the lack of overall public safety resilience governance，insufficient investment in infrastructure and equipment maintenance，an imperfect social environmental risk monitoring system，and weak information security awareness and literacy among residents. Specific measures can be taken from the aspects of humanistic concepts，clear strategies，systematic thinking，and diversified cooperation.

A two-dimensional diffusion model was developed using the computational fluid dynamics software Fluent across various longitudinal wind speeds to examine the impact of longitudinal ventilation in underground tunnels on the dispersion of thermal runaway gases from lithium-ion batteries. The findings demonstrate that the diffusion of thermal runaway gas on the upwind side of the gas inlet is restricted by longitudinal ventilation，while it is enhanced on the downwind side. At a wind speed of 3 m/s，the time it takes for thermal runaway gas to diffuse to the exit boundary in about 40% that when there is no wind. Moreover，increasing wind speed within the computational domain results in a larger diffusion area under the same diffusion time. The expansion of the explosion area generally exhibits an increasing-then-decreasing trend as diffusion time advances. In the wind speed range of 0.25-3 m/s，the maximum explosion area grows proportionally with wind speed，forming an exponential relationship. Notably，the maximum hazardous area reaches a minimum of 6.79 m² at a wind speed of 0.75 m/s. Considering the maximum explosion range，wind speeds between 0.5 and 0.75 m/s appear optimal for diluting and diffusing thermal runaway gas in the tunnel.

In order to develop the measurement of hydrogen sulfide content in coal seams towards informatization，intelligence，and automation，it is necessary to innovate the measurement equipment and technical methods. By analyzing the adsorption characteristics of H₂S in coal seams，the achievements in the development and application of hydrogen sulfide determination devices in recent years were summarized from the aspects of the convenience and accuracy of the construction of hydrogen sulfide determination devices. The current research status of methods for measuring hydrogen sulfide content in coal seams both domestically and internationally was elaborate. Finally，in view of the limitations of the equipment and methods for measuring hydrogen sulfide in coal seams，the future development direction of coal seam hydrogen sulfide measurement technology was discussed，and a technical system for improving the calculation error of coal seam hydrogen sulfide loss was proposed. An integrated coal sample underground crushing and desorption system，an automated desorption gas metering system，an intelligent monitoring and automated data analysis and processing system are constructed. The results show that the coal mine underground sampling method with internal and external double drill pipes，the loss of hydrogen sulfide during drilling and sampling is compensated. The measuring device is equipped with underground direct crushing equipment，filters，negative pressure vacuum tanks，and sensors for direct underground gas extraction and analysis，improving the accuracy of measuring hydrogen sulfide content in coal seams.

In order to swiftly elucidate the influence of internal parameters on the fracturing performance of a liquid CO₂ fracturing tool and optimize its functionality for enhanced coal seam gas extraction efficiency，a rapid assessment experimental apparatus was designed. A set of 9 orthogonal experiments involving 4 horizontal and 3 influencing factors was conducted utilizing a 38 mm mining-specific fracturing tool. The study analyzed the relative significance of the internal charge quantity in the heating tube，liquid CO₂ filling volume in the main pipe，the thickness of the fracture plate，and the caliber of the release aperture on the fracturing tool's performance. Furthermore，pivotal influencing factors were subjected to fixed-variable experiments to explore their impact patterns on the fracturing performance of the liquid CO₂ fracturing tool. Results indicate that，for the 38 mm mining-specific CO₂ fracturing tool，the thickness of the fracture plate exerts the most substantial influence on the fracturing tool's performance，followed by the internal charge quantity in the heating tube. The impact of the liquid CO₂ filling volume in the main pipe and the caliber of the release aperture is comparatively weaker. The fracturing performance of the liquid CO₂ fracturing tool gradually stabilizes with an increase in the thickness of the fracture plate，reaching a point where the plate does not rupture. When the internal parameters of the 38 mm fracturing tool are set to a CO₂ mass of 0.33 kg，a release caliber of 18 mm，a charge quantity of 60 g，and a fracture plate thickness of 2.0 mm，the tool's fracturing performance corresponds to a TNT(Trinitrotoluene) equivalent of 0.202 kg which is enhanced by 21.9 % compared to the current on-site parameters.

To address the issues of ambiguous multi-level，multi-link and multi-functional interaction relationships and the adverse coupling effects during operations in confined spaces，FRAM was introduced. Combined with ISM and AHP，the hierarchical structure and judgment methods were optimized and improved. By dividing the risk hierarchical structure，the impact of system function coupling variability was quantified，and the importance of functional units and hierarchical structures was calculated. Through the results of functional variability and coupling loss degree，the input-output phenotype of upstream and downstream functional changes were determined，and the coupling mechanism among system functional elements was clarified. The results show that by applying the risk prevention and control model for operations in confined spaces based on the improved ISM-FRAM-AHP，23 functional units and a 10-layer risk hierarchical functional network are obtained. The maximum values of functional variability and coupling loss degree are 4.36 (external environment F₂₃) and 0.808 4 (formulating operation plans F₂)，indicating a relatively high operation safety risk degree. The functional changes are mainly manifested in sequence，goal and control. Four effective functional barrier measures，physical，symbolic，functional and invisible，are proposed for 8 failure links.

In order to identify high-risk stations in urban rail transit systems and improve network resilience and operational safety，a performance function model was constructed to evaluate the network resilience by selecting network efficiency，average shortest path length and maximum connection sub-graph as indicators，and an evaluation method for critical stations was proposed，considering topological structure and passenger flow distribution equilibrium. Taking Nanjing Metro as an example，three cascading failure modes，descending critical degree，descending betweenness centrality and random sequence，are adopted. The characteristics of resilience degradation under different cascading failures are simulated respectively in the unweighted network and the weighted network. The results show that the critical stations are similar on weekdays and weekends. The resilience performance decreases most rapidly in the early stages of failures in descending order of critical stations. Compared with topology networks，the resilience index of passenger flow-weighted networks decreases faster in the early stages of cascading failures. Strengthening the control of critical stations when cascading failures do not spread widely can help reduce the loss of network resilience.

In order to improve the effectiveness of oil and gas pipeline accident prevention strategies，a classification model for the causes of oil and gas pipeline accidents was developed，and social network analysis was applied to the classification model. Firstly，the STAMP model and HFACS model were combined to get the control structure of oil and gas pipeline accident prevention，and then the causes of 35 oil and gas pipeline accidents at home and abroad were analyzed according to the control structure. The analysis results were coded using grounded theory to get the classification model for the causes of oil and gas pipeline accidents. Social network analysis methods were applied to construct a relationship network of factors related to oil and gas pipeline accidents，and core edge analysis，centrality analysis，and correlation direction index analysis were used to identify the core factors and factors with high correlation and strong influence in the oil and gas pipeline accident classification model. The research results show that the classification model for the causes of oil and gas pipeline accidents included 6 levels and 22 bottom cause factors，which are government and regulatory factors，third-party factors，operator organizational factors，operator unsafe supervision and the prerequisites for unsafe behavior of on-site personnel. Among the causal factors，the internal factors of the government and regulatory authorities，organizational factors of operators，unsafe supervision of operators，and third-party factors are core factors. System flaws，insufficient supervision，improper operation plans，third-party sabotage behavior，pipeline and weld defects，construction/repair/accessory issues，and skill errors are factors with high correlation and strong influence.

In order to evaluate the consequences of H₂S-containing associated gas leakage on the platform，ANSYS Fluent software was used to simulate the spatiotemporal changes of the gas diffusion. According to the development process of H₂S-containing gas diffusion，the toxic area of the associated gas cloud in two scenarios，namely no protective measures and emergency protective measures，were compared. A quantitative evaluation of the degree of toxic risk of H₂S-containing associated gas leakage was conducted by using the dose-response model. The results showed that compared to the scenario with no protective measures，after taking the “shutdown” measure，the volume and horizontal diffusion distance of the gas cloud with H₂S concentration ranging from 500-2 000 mg/m³ are reduced by 20%-37.5% and 15.4%-47.6%，respectively. After that，the toxic gas cloud volume and horizontal diffusion distance can be further reduced rapidly by taking the "blowdown" measures. By considering the H₂S accumulative concentration and exposure reaction，“shutdown + blowdown” measures can obviously reduce the fatality probability. The fatality of three monitoring spots near the leakage hole decreases from 0.998，0.034 and 0.000 239 to 0.759，0.002 9 and 0.000 000 65 respectively. The area of intolerable section and ALARP section of horizontal plane on the middle deck decrease by 63.7% and 81.7% after taking the emergency protective measures. The hazardous degree of toxic consequences caused by associated gas leakage can be significantly reduced.

To reveal the characteristics of coal mine accidents in China in recent years，and put forward targeted countermeasures and suggestions for accident prevention，firstly，the major and catastrophic coal mine accidents in China from 2013 to 2023 were collected and analyzed from the aspects of the year，type，month，province and cause of the accident. Secondly，taking "2·22" particularly serious collapse accident in Inner Mongolia Xinjing coal mine as an example，the accident was analyzed based on 24Model. Finally，combined with the above analysis and research results，the accident prevention countermeasures and suggestions in line with the current situation of coal mine safety production in China were put forward. The analysis and research results show that the number of major accidents and deaths in coal mines has shown an overall downward trend，and the level of coal mine safety production in China has significantly improved since the 12^th Five Year Plan. Gas accidents are still the main accidents in coal mines in China，accounting for 51%. The fourth quarter of each year is a period of high incidence of coal mine accidents，accounting for 30.43% of the total number of accidents. Affected by geological conditions and occurrence，accidents often occur in the main coal producing areas. The proportion of accidents caused by unsafe human behavior is as high as 74%. When there are hidden dangers at both the individual and organizational levels and the dual prevention measures are not in place，accidents are likely to occur. Countermeasures and suggestions for reducing coal mine safety accidents are put forward from four dimensions，including safety supervision，strengthening safety through science and technology，team development and safety culture.

To achieve the accurate evaluation of steel structure fire resistance in the converter station，based on the possible standard，power and hydrocarbon fire scenarios，the thermal insulation mechanism of ultra-thin fireproof coating as well as its thermal insulation performance on steel members with different steel materials and different cross-section shape factors were investigated through micro-scale thermogravimetric-Fourier transform infrared (TG-FTIR) spectroscopy experiments and small-scale fire test furnace heat insulation experiments. The experimental results show that the faster the fire heating rate，the higher the peak mass loss rate and the higher the peak temperature of the fireproof coating. Different fire heating curves have no effect on the type of gases escaping from the thermal decomposition of fireproof coatings，but have an effect on the amount and peak temperature of escaping gases. Compared with the power and hydrocarbon fire，in the condition of standard fire，more gases are produced before 750 ℃，resulting in better expansion and heat insulation. Furthermore，the fire resistance of the ultra-thin fireproof coatings on the carbon steel and stainless steel at various cross-section shape factors at power and hydrocarbon fire is worse than that of standard fire，indicating poor heat insulation abilities.