Cone-shaped hollow foundation is a new form of onshore wind power foundation, which has the advantages of low steel and concrete consumption and reduced waste soil generation during excavation of the foundation pit, compared with the traditional gravity foundation. In order to investigate the bearing characteristics of a cone-shaped hollow foundation under combined loads, a numerical simulation was carried out to investigate the influence of the ratio of the diameter of the top plate to the diameter of the bottom plate on the combined bearing capacity and damage mode of the foundation when the volume of the foundation is held constant. The results demonstrate that when the ratio of the diameter of the top plate to the diameter of the base plate is 6, the vertical ultimate bearing capacity of the cone-shaped hollow foundation is 100% higher than that of the same volume gravity circular foundation, and the moment ultimate bearing capacity is 60% higher. The failure envelopes of different diameter ratios of the cone-shaped hollow foundation can be described by a curve under different combination loads, and the expressions of the failure envelopes of different combination loads are proposed. The failure envelopes of gravity circular and cone-shaped hollow foundations under combined horizontal and bending moment loads show obvious asymmetry, with opposite directions of eccentricity. When the horizontal and bending moment loads are in different directions, the circular foundation has higher bearing capacity. When the horizontal and bending moment are in the same direction, the cone-shaped hollow foundation has higher bearing capacity. The cone-shaped hollow foundation shows a better combination of load-bearing capacity, which can be provided for the super-large single installed capacity wind turbine.

The precision of temperature field control in the hypersonic wind tunnel directly affects the accuracy of wind tunnel test data. In view of the control problems of hypersonic wind tunnel temperature field control, such as large delay, nonlinear and multi-variable coupling, phase space reconstruction of data affecting temperature was carried out and support vector regression was applied to the hypersonic wind tunnel temperature field predictive control to improve the accuracy and efficiency of hypersonic wind tunnel temperature field control. At the same time, considering that the selection of kernel function in support vector regression machine and the optimization of kernel function parameters affect the accuracy of prediction results, the support vector machine model was established based on different kernel functions, and the optimal kernel function was selected through comparative verification and analysis, and the corresponding PSR-SVR model was established to predict the temperature field of the hypersonic wind tunnel, so as to improve the temperature prediction accuracy. The analysis of actual temperature field data shows the effectiveness of the proposed method.

The resilience theory has been introduced into the aviation logistics supply chain to enhance its ability to withstand internal and external shocks and uncertainty. A resilience evaluation model for the aviation logistics supply chain based on a Bayesian network was proposed. The Bayesian network structure index was established from the macro performance layer, the middle influence layer, and the bottom cause layer. Subsequently, the Bayesian network model was constructed, and the probability inference process of the Bayesian network nodes was completed using the Markov Chain Monte Carlo algorithm. This enabled the acquisition of the probability distribution of aviation logistics supply chain resilience through parameter learning and model inference. Furthermore, the Bayesian network model was employed for reverse reasoning, sensitivity analysis, and cause chain analysis to identify the key variables and sensitive factors affecting the resilience of the aviation supply chain. Based on these analyses, suggestions for improving resilience were put forward. Research findings indicate that the resilience value of China's aviation logistics supply chain is approximately 53%, signifying a high level of resilience. The Bayesian network model has proven effective in quantifying the resilience value of the aviation logistics supply chain, as well as in reasoning and analyzing the influence of each factor on resilience value, thus contributing to the enhancement of the risk resistance ability of the aviation logistics supply chain.

Antibiotics are new pollutants in water environment, which have potential threat to aquatic ecological environment and human health. Considering that sulfanilamide antibiotics are difficult to degrade and oxidize and cannot be effectively removed by sewage treatment plants, Fe₇₈Si₉B₁₃/H₂O₂ system was constructed to efficiently and environmentally degrade sulfanilamide antibiotic pollution. Fe₇₈Si₉B₁₃/H₂O₂ system was selected as the best process for efficient degradation of SDZ(sulfadiazine) through a series of experiments with different experimental parameters. The experimental results show that 250 μg/L SDZ can be degraded 100% within 4 min at pH=2, H₂O₂=50 μmol/L and temperature 25 ℃, and its apparent rate constant (K_obs) can reach 0.99 min^-1. The activation energy of SDZ removal in the system is 25.42 kJ/mol. The quenching agent experiments show that the key active substance of Fe₇₈Si₉B₁₃/H₂O₂ system degrades SDZ is hydroxyl radical (·OH). Through high resolution identification of intermediates and toxicity assessment of the intermediates, the results show that all intermediates are substantially reduced or harmless compared to the mother. In addition, the practical application potential of the oxidation degradation system is verified through the actual water degradation experiment.

In order to improve the efficiency of finite element analysis and reduce memory consumption, the storage algorithm of the overall matrix was studied. The constraints were uniformly processed as matrix partitions at the element level. Subsequently, taking the stiffness matrix as an example, the distribution pattern of non-zero elements under the constrained condition was determined. A calculation method and corresponding formulas suitable for the number of non-zero elements in the stiffness matrix of two-dimensional and three-dimensional finite elements were proposed, and the correctness was verified. The correspondence between one-dimensional equal bandwidth storage and the original square matrix address was deduced, and it was applied as an auxiliary array in the process of integrating the overall matrix in CSC format, which has improved the efficiency of the overall matrix assembly and avoided the difficulty of node numbering optimization. Finally, the correctness and practicability of the proposed algorithm were verified by using thefour-span single-line girder bridge in the Changdao section of the Fangshan Line in Beijing. The results show that the overall matrix assembly time is reduced by 30%, the storage space is saved by more than 68%, and the calculation efficiency of linear equations is improved by more than 71% while ensuring the calculation accuracy.

Deformation law is of significant for ensuring the safety of structures and environment during the large diameter shield tunnelling. Particularly for shallow and large diameter shield tunnelling in soft soil, the mutual coupling of high compressibility and low shear strength of soft soil and low overburden load under shallow burial conditions as well as the unloading effect of large excavation will lead to a more complex construction deformation mechanism. Hence, the characteristics of structure vertical deformation, structure convergence deformation and surface deformation caused by shallow and large diameter shield tunnelling in soft soil and their mechanism were studied, based on the dynamic deformation monitoring of a shallow buried large-diameter shield tunnel of Shanghai Suburban Railway Airport Link Line. The results show that the ephemeral demarcation times for different deformation types were closely related. The vertical deformation of the structure can be divided into 4 stages: prior uplift, fluctuating uplift, continuous uplift, and relative stability. The structure convergence deformation can be divided into 3 stages: fluctuating convergence, continuous convergence, and stable convergence. And there are 3 stages, perturbation settlement, rapid consolidation, and relative stability in the vertical deformation of the axial surface. There are significant differences in the vertical structure deformation caused by uneven distribution of additional pressure on the tunnel structure. The maximum vertical surface deformation in the tunnel axis would exceed the warning value and the final settlement deformation would be approximately 84.3% the maximum deformation. The width of the surface sinkhole and location of the maximum settlement are closely related to the depth-to-diameter ratio, but the “swell ridge” distribution would be evident when the depth-to-diameter ratio is relatively large. In about 21~50 d after the excavation construction, the amplitude of structure vertical deformation, structure convergence deformation and surface vertical deformation is significant, and the deformation trend is relatively explicit, which is the key stage to improve the deformation control and remediation effect. The findings of this study are intended to serve as a significant reference for the control of structure deformation and environmental safety protection of shallow and large diameter shield tunnelling in soft soil.

Unconventional tight reservoirs are characterized by strong non-homogeneity, low resource abundance, low porosity and low permeability. Compared with onshore unconventional reservoirs, hydraulic fracturing of offshore tight gas reservoirs has greater safety risks greater and more operational difficulties, leading to greater difficulty in balanced reservoir modification. Therefore, deployment of horizontal wells for hydraulic fracturing development in offshore tight gas reservoirs requires precise evaluation of reservoir geomechanical characteristics, analysis of the fracturability of horizontal well sections, and fracturing of well sections with similar geomechanics, which can support precise, balanced and efficient development of offshore gas reservoirs. Taking a tight gas reservoir in offshore as the research object, in this study, an engineering fracturability analysis method based on brittleness and in-situ stress difference was proposed, and an engineering sweet spot prediction model was established by kernel density estimation method to estimate the probability density function and cumulative probability function of engineering fracturability. Based on the engineering sweet spot prediction, hydraulic fracturing segments were optimized to achieve a differentiated design of segment spacing. Based on the concept of integrated geological and engineering, hydraulic fracturing simulation and production prediction were carried out in this study. The simulation results verified the feasibility of hydraulic fracturing and the reliability of engineering sweet spot prediction in target reservoir, which provides a significant technical support for the optimization of horizontal well fracturing scheme and large-scale beneficial development of offshore tight gas reservoirs.

The evaluation of grouting defects in precast beam grouting sleeves has long been a focal point of scholarly research, with the impact of horizontal defects on performance surpassing that of end and vertical defects. Aiming at the problem of horizontal grouting defect evaluation, the active excitation signal of AST (auto sensor test) and PLB (pencil-lead breakage) function built in acoustic emission instrument was studied, combined with horizontal sleeve grouting fullness test.Through parameter analysis and fast Fourier transform, changes in acoustic emission wave velocity, energy, count and waveform parameters are examined at filling degrees of 50%, 60%, 70%, 80%, 90% and 100%. Furthermore, the correlation between acoustic emission energy, count parameters and main frequency amplitude with grouting fullness was established. The results show that when the excitation source is AST, the acoustic emission energy, count and the main frequency amplitude of its waveform show a good negative exponential correlation with the increase of grouting sleeve fullness, and the combination of the relational equations allows for quantitative acoustic emission analysis and evaluation of grouting fullness of horizontal grouting sleeves.

A semantic segmentation-based method for defect segmentation on thin strip cast and rolled steel plates was proposed to accurately and quickly identify surface defects. Firstly, defect images from the production line were annotated using Labeling software to create a defect segmentation dataset. Secondly, a TransUNet network model was established to recognize and segment surface defects, integrating an optimized DANet dual-attention fusion network to enhance model segmentation performance. Finally, comparative experiments between the improved model and other segmentation models were designed. The feasibility and effectiveness of the proposed method are verified through analysis of experimental results and evaluation metrics. The experiments demonstrate that the improved network achieves a segmentation accuracy of 96.85%, an average intersection over union of 96.99%, and a similarity coefficient of 92.98% for foreign object defects on thin strip cast and rolled steel plates, respectively increasing by 1.19%, 0.61%, and 0.63% compared to the TransUNet network. Additionally, the improved network achieves a segmentation accuracy of 92.86% on the publicly available hot-rolled strip steel defect dataset, indicating its versatility and providing technical guidance for intelligent detection of surface defects on steel plates.

In order to solve the problems of SHO (seahorse optimization), such as low accuracy, precocity and insufficient global search ability. MSHO (multi-strategy seahorse optimization) algorithm based on nonlinear inertial weight strategy, improved whale encircling strategy and improved sine and cosine strategy was MSHO designed. Firstly, the nonlinear inertia weight was introduced into the motion behavior of SHO algorithm to overcome the shortcoming that the algorithm is prone to premature convergence. Secondly, the improved strategy of whale encircling prey was introduced into the updated equation of seahorse hunting success to reduce the probability of the algorithm falling into the local optimal solution. Then, the improved sine-cosine strategy was introduced into the reproduction behavior of the algorithm to enhance the quality of the hippocampal progeny solution, and further improve the global optimization ability and stability of the algorithm. Finally, in order to evaluate the performance of the proposed MSHO algorithm, SHO algorithm, chaotic SHO algorithm, subtraction average algorithm, gray Wolf algorithm, Seagull algorithm, whale optimization algorithm, particle swarm algorithm and MSHO algorithm were compared on 23 benchmark test functions. The experimental results show that MSHO algorithm shows higher convergence accuracy on 20 functions and stronger stability on 16 functions compared with other 7 algorithms. In addition, in order to test the application ability of MSHO algorithm in engineering problems, the algorithm is applied to solve the design problems of welded beams, cantilever beams and pressure vessels. The experimental results show that MSHO algorithm has better search accuracy in these three kinds of engineering design problems than other 7 different algorithms.