In order to estimate carbon storage and investigate its influencing factors in typical karst rocky desertification regions, Jianshui County, located in the upper reaches of the Yangtze River and within the Nanpan River Basin, was selected for study due to its significant ecological position. Data from Landsat 5 Collection 1 Tier 1 Surface Reflectance, Landsat 8 Collection 1 Tier 1 Surface Reflectance, and digital elevation model (DEM) were used to conduct the analysis. The google earth engine (GEE) platform and the integrated valuation of ecosystem services and trade-offs (InVEST) model was used to estimate and predict carbon storage, while the geodetector tool was employed to analyze influencing factors. The results show that, between 2000 and 2020, Jianshui County was predominantly classified as potential rocky desertification and non-desertification, with the rocky desertification area found to have decreased by 115 km² overall, and the non-desertification area increased by 21 km², reflecting an improvement in desertification conditions. Carbon storage displayed a spatial distribution pattern of “higher in the north and south, lower in the center,” with recorded values of 116.293 t, 113.310 t, and 118.363 t in 2000, 2010, and 2020, respectively, demonstrating an initial decrease followed by an increase. Projections suggest that carbon storage may reach 129.981 t by 2030. Temperature (q=0.672) was identified as the primary factor affecting changes in carbon storage, with the interactions between factors shown to have a stronger effect on carbon storage than individual factors, especially the interaction between slope and temperature (q=0.998), indicating a non-linear enhancement. It is concluded that carbon storage in Jianshui County exhibits a trend of initial decrease followed by increase, influenced by both natural and social factors, with a spatial pattern of “higher in the north and south, lower in the center.”

In order to evaluate the characteristics of fire smoke dispersion in large-space buildings, FDS software was used to investigate the effects of air-inlet position, smoke-proofing depth and smoke exhausting rate to the working efficiency of fire isolation belt. The results show that, by opening the air-inlet in the non-fire zone and closing that in the fire zone, a reverse airflow can be induced below the fire isolation belt, which resists the smoke overflow and reduces the disturbances to the smoke layer. The increase of the smoke-proofing depth can increase the space for smoke storage and reduce the height of the smoke layer, thus delaying the instant of smoke overflow by decreasing the generation rate of fire smoke. In the scenario without mechanical smoke exhausting in the fire isolation belt, the instant of smoke overflow can be delayed by about 50% when the smoke-proofing depth increases from 20% to 40%. By adopting mechanical smoke exhausting in the fire isolation belt, the accumulated smoke can be timely extracted, which can effectively prevent the smoke spilling into other non-fire zone. It is concluded that, through an overall consideration to the smoke isolation efficiency, building functions and construction costs, the combination of “40% smoke-proofing depth + adopting the mechanical smoke exhausting rate with reference to the Smoke Standard + opening the air-inlet in the adjacent non-fire zone” is recommended as an advantageous design principle for fire isolation belts.

In order to study the effect of freeze-thaw cycle on the stability of lime-amended loess slope, the change rule of shear strength and soil-water characteristics of lime-amended loess under different numbers of freeze-thaw cycles was obtained by straight shear test and soil-water characteristics test, and the stability of high-fill loess slope was analysed by using the strength discount method with MIDAS GTS NX software. The results show that: the internal friction angle and cohesion of the soil samples both increase with the increase of the age of maintenance, and with the increase of the number of freeze-thaw cycles, the internal friction angle of the soil samples will first increase and then gradually tend to be stable, and the cohesion will first decrease and then gradually tend to be stable; the lime-amended loess has its matrix suction maximum at the lowest temperature of the first freeze-thaw cycle, and its matrix suction is minimum at the second freeze-thaw cycle, and after that the matrix suction of the soil body increased. Freezing and thawing cycles will cause the slope infiltration flow rate to increase; the trend of pore water pressure changes in the freezing and thawing slope model is the same as that of the unfrozen slope, and the pore water pressure is positive at the bottom of the slope model, and then decreases gradually near the top of the slope, and then reaches the minimum at the top of the slope. The freeze-thaw cycle will cause the strain of the slope to increase under rainfall conditions, which affects the safety and stability of the slope; the shallow freeze-thaw has little effect on the safety of high-fill improved loess slopes.

Gas storage operations can be significantly impacted by abnormal wellbore temperatures at natural gas storage sites. Accurately predicting wellbore temperatures is of paramount importance for enhancing the safety and efficiency of these operations. Based on the analysis of operational parameter correlations, a gas storage wellbore temperature prediction method was proposed using advanced spatiotemporal graph convolutional neural network (A-SGCN). Both GCN and long short-term memory (LSTM) networks were employed by A-SGCN to capture spatial and temporal dependencies, respectively. Based on this framework, an adaptive residual attention mechanism was incorporated to effectively capture the intricate relationships between spatiotemporal data, ultimately enabling accurate temperature prediction. The effectiveness of the method is validated through its application at the Huangcaoxia gas storage No.2 injection-production station. Accurate prediction of wellhead temperature at Well No.1 is achieved through the association of monitoring parameters between Well No. 1 and Well No.6.

In frastructure projects such as hydropower, harbours and transport are usually constructed by rockfill of aggregates from local materials, however, the shapes of rockfill of aggregates in different regions are quite different. In order to study the effect of aspect ratio on the K₀ consolidation characteristics of rockfill, firstly, 10 kinds of particle clusters with different aspect ratios were generated by the discrete element method, and then the same equivalent particle size was taken to generate the specimens with the same initial state in the same way, and then the K₀ consolidation test was carried out at last, and the effect of the aspect ratio of the particles on the K₀ consolidation characteristics of the heap stone materials and its micro-mechanisms were explored in detail. The results of the study show these as fouows At the macro level, the specimens with different aspect ratios of rockfill are divided by AR=0.5, when the AR is 0.5~1, the K₀ value of the specimens increases with the increase of aspect ratio, and when the AR is 0.2~0.5, the trend of the change of the K₀ value of the specimens with the increase of the aspect ratio is unknown. This suggests that the particles in the interval of aspect ratio 0.5~1 need to be focused on during engineering design. At the microscopic level, the smaller the particle aspect ratio (the longer the particles), the larger the coordination number, the smaller the average force between the particles, and the smaller the cumulative angle of rotation of the particles, which suggests that the contact between the particles of the specimens with smaller particle aspect ratios is closer, the contact force chain is more dispersed, and the particles are more resistant to rotation. This may be the reason for the differences in K₀ consolidation properties of rockfill with different aspect ratios. The research results can provide theoretical references for the evaluation of K₀ values in areas where there are particle shape differences, and provide a basis for selecting appropriate rockfill materials, ensuring the safety of the project.

In view of the position control accuracy and body chattering of small unmanned helicopter under large disturbance, an improved sliding mode controller (SMC) was proposed. Firstly, for the unknown parameters in the dynamic model of small unmanned helicopter named Align T-REX 300, three flight experiments were designed for the data acquisition, determining the comprehensive aerodynamic parameters. Then, the dual-channels control strategy with an improved SMC was designed to realized the helicopter hovering. The parameters ranges of SMC were presented by combining stability analysis, which can effectively suppress chattering. The model validation experiment shows that the aerodynamic parameters determined by the flight experiments have high fidelity. Moreover, the control simulations show that the steady state error of the step responses is less than 0.02 under the continuous large disturbance. Under the improved SMC with high control accuracy and weak tremor, the servos' control signal curves are smooth, which is more conducive for achieving the flight control of unmanned helicopter under the disturbance in actual engineering.

Aiming at the current aviation typical parts with complex structure and high precision requirements, increased difficulty in quality inspection but backward inspection methods, an inspection plan automatic preparation method was proposed. Firstly, from the information reuse and information integration, the inspection number model was constructed on the basis of the design model, which layed a foundation of data source for the generation of the inspection plan. Secondly, the production method of the inspection plan was formulated, and the rules of the inspection sequence generation were designed, to achieve the automatic generation of inspection sequence number by using the improved Dynamic planning algorithm. Finally, combined with the CAA(component application architecture) secondary development interface and Excel component development, the corresponding function module was developed under the CATIA environment, to achieve the output of the inspection element information and process view, to complete the automatic preparation and export of the inspection plan. Through examples, it is proved that the method can reduce the labour intensity of inspectors and improve the efficiency of the preparation of inspection plans.

In the event of a public health emergency, the selection of the optimal distribution locations of daily necessities is crucial. Accordingly, the emergency distribution of daily necessities in Changchun City was taken as an example for empirical research and an optimization algorithm was proposed for the location of emergency supplies distribution. Initially, the virtual material warehouses, distribution candidate locations, and service coverage areas were determined by using K-means clustering and the Thiessen polygon method. Then, an optimization model was established with the goals of maximum coverage and minimum cost, and an improved genetic algorithm based on adaptive elite retention strategy was proposed to solve it. Empirical research had shown that the clustering algorithm could obtain 873 virtual material warehouses and distribution candidates, while Thiessen polygons could determine the reasonable coverage range of candidates, and improved genetic algorithms could obtain better 30 material warehouses and distribution locations. Data analysis had also found that there was a time lag between the distribution of supplies and effective control of infection. Therefore, once the rate of new additions exceeds the normal value, emergency supplies should be increased in advance to control further outbreaks of possible infections.The research results are beneficial for enhancing the ability of urban crisis management and emergency response, ensuring timely and efficient supply of daily necessities.

The double bottom blowing lead smelting is a representative kind of oxygen-enriched enhanced molten pool smelting process. Comparing with the traditional ore lead smelting,its production operation is more complex for coprocessing lead based solid waste. In order to ensure its production status in a stable and economic state, there are higher requirements for its process control. MetCal desk metallurgical computing platform was used to establish a calculation model for the double bottom blowing lead smelting process for coprocessing lead based solid waste through the principles of material balance, thermal balance and chemical balance in the smelting process. The process parameters of the double bottom blowing lead smelting process for coprocessing lead based solid waste were simulated and calculated. Meanwhile, the model was modified and controlled by the feedback control algorithm to make it more in line with the actual production situation, which can provide guidance for the actual production operation of the process engineers and realize the optimal control of the process.

To enhance the support for the nuclear safety review of domestic advanced pressurized water reactor (PWR), the reactor coolant pump (RCP) shaft seizure accident for this reactor type was conducted. The impact of the loss of offsite power (LOOP) assumption and moderator temperature feedback on the accident consequences was examined. The findings are as follows. The peak pressure in the reactor coolant system and the peak temperature of the hot spot cladding, recorded during the accident process, met the accident acceptance criteria, enabling the nuclear power plant to eventually stabilize. The LOOP assumption was found to be conservative. For this accident, however, the differences arising from this assumption manifested in the later stages and did not influence key outcome parameters such as system pressure peak, minimum departure from nucleate boiling ratio (DNBR), and peak temperature of hot spot cladding, which occurred early in the accident. Therefore, the inclusion or exclusion of the LOOP assumption was deemed acceptable. The introduction of moderator temperature feedback was considered an unconservative assumption. Nevertheless, even without this feedback, the peak pressure in the reactor coolant system and the peak temperature of the hot spot cladding still met the accident acceptance criteria, maintaining a substantial margin. Additionally, incorporating moderator temperature feedback brought the calculations closer to reality. Overall, the introduction of moderator temperature feedback in this accident was also judged to be acceptable.