To address the problem of incomplete reflection of network structure characteristics and data distortion in static network models used in dynamic systems，an airport network structure analysis method based on a temporal complex network model was proposed by introducing time attributes. Network characteristic indicators such as nodal temporal degree，temporal centrality，temporal betweenness centrality，and temporal closeness centrality were analyzed. Then，the structural properties of CAN were investigated. Moreover，crucial airport nodes within the temporal network were identified and ranked，and the reasons for the heterogeneous node generation were analyzed. The results indicated that the temporal network structure of Chinese airports presented scale-free network characteristics. The average temporal distance values of CAN vary significantly with the maximum being 6.06 times the minimum. ZWWW (Urumqi Diwopu International Airport) and ZBHH (Hohhot Baita International Airport) represented relatively higher temporal betweenness centrality than other indicators，playing an important central role in the network. However，ZGSZ (Shenzhen Bao'an International Airport) had a higher temporal degree of centrality than other indicators.

In order to reduce conflicts between heterogeneous traffic flows during overtaking，a non-motorized lane width design method that considers avoidance maneuver in heterogeneous traffic was proposed. This method represents an improvement over the traditional design approach. Firstly，the conflict levels of non-motorized vehicles were analyzed through the deceleration group proportions and pedaling cadence. Secondly，a vehicle-to-vehicle force model was established to calculate the forces between different types of vehicles. The additional safety gap was determined based on the relationship between these forces and lateral width. The recommended non-motorized lane width was the sum of the traditional lane width and the additional safety gap. Then，the rationality of the proposed design method was evaluated based on the safety levels of non-motorized lanes with different widths，which was obtained from the safety evaluation model developed in this research. Finally，data from four non-motorized lanes in Xi'an city were analyzed as case studies. The research results show that the deceleration group proportion is 0.93 times，pedaling cadence increases by 0.07 revolutions per second，and the road safety value is 1.07 times compared to traditional non-motorized lanes in non-motorized lanes accommodating heterogeneous traffic. These findings demonstrate that lanes meeting the design width have lower conflicts and greater safety.

Excessive damage to aircraft braking moving discs will directly threaten flight safety. In order to solve the problems of low detection efficiency and strong subjectivity in the evaluation of damage degree of braking moving disc based on manual experience，an intelligent evaluation algorithm for damage degree and replacement need of aircraft braking moving disc based on image segmentation was proposed. Firstly，the classification and feature information of braking moving disc damage were analyzed. Then，based on the U-Net model，semantic segmentation was performed on the braking moving disc damage image dataset. A quantitative analysis model for the proportion of braking moving disc damage area and a calculation model for the maximum radial width of the fall off area were constructed. Finally，the model was validated using image data of the braking moving disc of Cessna525. The results indicate that the U-Net model has a good image segmentation effect on the types of braking moving disc damage，with average accuracy，average recall，average pixel accuracy，and average intersection to union(IoU) of 90.75%，91.25%，90.25%，and 87.25%，respectively. The evaluation results of braking moving disc are basically consistent with the evaluation conclusions of experienced mechanical engineers，and the evaluation results are objective，accurate，and highly visualized，which proves the rationality and feasibility of the algorithm proposed in this paper.

In order to prevent transformer fire accidents，short-chain fluorocarbons (FS-50) were combined with non-ionic (Alkyl Polyglucoside(APG)-0810)，zwitterionic (Disodium Cocoamphodiacetate(CAD)-40) and anionic (Sodium Dodecyl Sulfate(SDS) )three kinds of foam solutions，APG-0810/FS-50，CAD-40/FS-50 and SDS/FS-50 were prepared. The basic properties，foamability，foam and liquid film stability of the foam solution in the presence of transformer oil were systematically studied. The curves of foam drainage，volume decay，oil volume and film thickness were obtained over time. The results show that oil has a significant influence on foam properties. Under the action of transformer oil，the foaming ability of the foam solutions decreased significantly，and the foaming ability of APG-0810/FS-50，CAD-40/FS-50 and SDS/FS-50 were reduced by 16.9%，18.4% and 18.8% respectively. The volume of drainage in 60 min increased by 13.6%，74.6% and 15.5%，respectively. Foam volume decay increased by 2.5%，9.8% and 17.9%; The stability of liquid film decreased，and the film thickness decreased by 276.5，414.7 and 552.9 nm，respectively，at 100 s. Among the three foam solutions，the mixture of APG-0810/FS-50 has the best inhibition ability to transformer oil，and the stable foam of this system has the best oil resistance to transformer oil. The research results of this paper can provide a theoretical basis for the development and selection of special extinguishing agent for transformer oil fire.

In the application process of blockchain technology，insufficient attention has been paid to the research on safety barriers that are more suitable for preventing complex system safety problems. To solve this problem，firstly，the safety requirements of blockchain itself and the support of safety barrier theory were introduced，which was combined with the security application of blockchain technology in the industrial field. Then，the main safety barrier models within qualitative and quantitative perspectives were summarized，so were the progress of security analysis model of software system and of performance evaluation of safety barrier. Then，the research status of safety precautions related to security risks of blockchain technology was summarized. Finally，in accordance with the trend of coupling coordination in safety barrier models，a research framework of safety barrier models related to the application of blockchain technology was put forward，which was based on the research progress of quantitative methods studying complex system coupling coordination and complex causal mechanism. It was a framework system including safety analysis，situational construction，system modeling，mechanism analysis，effect assessment and implementation path. The results show that the research on the safety barrier models related to blockchain technology should cover static series diagram pattern with Bow-Tie model as core and ARAMIS(Accidental Risk Assessment Methodology for Industries System) and coupling perspective STAMP (Systems Theoretic Accident Model and Processes) models as integrators，dynamic evolution mechanism research that includes dynamic Bayesian network analysis by transforming the static models into BN，and the effect assessment of safety barrier system. The study on coupling coordination and nonlinear causal analysis focusing on entropy deepen this coupling integration research system.

In order to study the wall dynamic response and damage characteristics of deep roadway with high geostress in gas explosion accidents，a mathematical model and a physical analysis model of the roadway wall dynamic response damage were established by using LS-Dyna software，and the numerical model was verified. The displacement，stress and damage characteristics of the roadway wall under the dynamic and static loads of gas explosion impact and geostress were analyzed by numerical simulation. The response and damage change of the roadway wall under different geostress conditions (horizontal geostress and vertical geostress) and gas explosion impact loads were investigated. The results show that high geostress causes the initial damage deformation. The stress concentration and initial damage are greatest at the corner，but its dynamic response is smaller than that at the roof. Under the dynamic and static loads of gas explosion impact and geostress，the damage strain of each part of the roadway increases with the increase of geostress，among which the damage degree at the corners is most affected and most serious，followed by the roof position. The increase of geostress makes the initial damage deformation of the roadway wall more serious，but it obviously weakens the propagation of the shock wave in the surrounding rock.

In order to explicit the distribution characteristics of polluted gases in factory buildings and realize efficient control of industrial building environments，the study analyzed the differences and simplification conditions between the distribution characteristics of multiple gaseous pollutants and single gaseous pollutants，clarified the transportation characteristics of multi-component mixed gases emitted simultaneously from the same source，revealed the feasibility range and principles to be followed for mass transfer simplification of multi-component mixed gases in full scale，and verified the validity of the conclusion through numerical simulation. The results show that the applicable range of the multi-component gas mass transfer simplification model is as follows: when the mixed gas emitted from the same source has no phase change and chemical reaction，and its flow parameter Reynolds number Re is above 10³ and Mach number Ma < 0.3，and the physical property parameters are within the range of Knudsen number Kn < 0.01 and temperature between 0.3 Characteristic vibrational temperature θ_v and T'，the components can be simplified for studying the distribution characteristics of pollutants. The simplified deviation stems from the difference in volume force per unit mass of the mixed gas before and after simplification (ΔF). When simplifying，it is necessary to ensure that the ratio of ΔF to the main driving force is less than 0.01. The theoretical model's application range and simplification principle agree with the simulation results. It is proved that a variety of gaseous pollutants can be simplified into a single type under the condition that the simplification principle is met within the applicable scope to explore the distribution characteristics of pollutants.

In order to prevent hard landing overrun events of civil aircraft，first，data including kinematics，system performance and other engineering parameters was collected from QAR. Then QAR data processing activities such as the airport segment clustering，sample balancing and statistical feature extraction were carried out. Subsequently，LightGBM model was used to predict the hard landing events of civil aircraft，and compared with extreme gradient boosting (XGBoost)，decision tree (DT) and long short-term memory (LSTM) models. Finally，the shapley additive explanation (SHAP) algorithm was employed to identify the causal mechanisms of hard landing events and to analyze the impact of various flight parameters on the model's prediction results. The result demonstrates that the proposed model not only exhibits high accuracy and precision in predicting hard landing events (accuracy，correctness and recall reaching 99%，92% and 88%，respectively)，but also provides quantitative and visual explanation information for the decision-making process of hard landing prediction for specific flight segments.

In order to investigate the expansion law of high flow grouting material and the creep mechanical properties and pore structure of coal after grouting，a new nonlinear viscoplastic element was created and a creep mechanical model was constructed. Firstly，the high flow grouting material was prepared and injected into the coal body to simulate the coal body grouting around the borehole. Secondly，mercury injection experiment and uniaxial fractional loading creep test were used to test the pore structure of the coal after grouting and the creep performance of the coal under different stress levels，and the strain variation law of the coal at different creep stages was obtained. Finally，based on the creep test results，a new nonlinear viscoplastic element was constructed and introduced into the Boedin-Thomson model. Finally，the relevant parameters of the creep model were obtained by inversion，the reliability of the model was verified，and the creep instability failure law of the coal after grouting was obtained. The results show that the expansion rate of high flow grouting material is 92% higher than that of ordinary cement material，which effectively improves the shrinkage problem of cement-based grouting material after curing. After the high flow grouting material is injected into the coal body，the critical load of instability failure of the coal body is 15.3 MPa，which improves the stability of the coal body to some extent.

To effectively enhance the transportation capacity of compressed air foam and better address the fire hazards in converter stations，experimental research was conducted on pressure distribution using full-scale compressed air foam transport pipelines of 699，406 and 261 m as examples. Furthermore，the equivalent resistance length method was proposed to consider static pressure loss and local pressure loss，and a comprehensive equivalent resistance coefficient was introduced. An empirical pressure loss relationship suitable for engineering applications was developed. The results indicate that during the compressed air foam transport phase，the pipeline inlet and outlet pressures rapidly increase with time before stabilizing. The time required to reach a steady state is proportional to the length and complexity of the pipeline. After foam transport ceases，the pressure within the pipeline drops sharply. The complexity of the pipeline configuration leads to a nonlinear decrease in local pressure with increasing transport distance. Finally，an empirical relationship between the pressure loss and the equivalent resistance length has been obtained，which can be used to predict pressure drop variations for pipe diameters ranging from DN50 to DN200 and pipeline lengths up to 1 000 m.