Laser 3D scanning technology rapidly acquires point cloud data of target surfaces, including spatial point coordinates that describe the geometric features of the target and laser reflectance intensity that characterizes the material’s reflectivity. The application of automatic semantic segmentation techniques for 3D point clouds in geological exploration research lays the foundation for depicting regional geological features. To demonstrate the recent advancements of 3D laser scanning technology in large-scale semantic segmentation within geological scenarios, firstly, photogrammetry and LiDAR as two methods for acquiring 3D point clouds were compared, highlighting the advantages of LiDAR in terms of accuracy, versatility, and insensitivity to lighting conditions. By elucidating the principles of lithological semantic segmentation, a comprehensive review and summary of recent methods based on geometric or intensity features were provided. Common large-scale point cloud datasets and evaluation metrics were introduced, and the segmentation performance of different algorithms was compared. Finally, the limitations of existing methods were summarized, and future research directions for lithological semantic segmentation tasks were outlined.

For the problems of low efficiency and long computational time in the fluid-structure interaction of free-surface flow and elastic structure, an efficient fluid-structure coupling method for free surface flow was developed by combining the volume of fluid method with the fast dynamic mesh method based on the structure-pseudo elastomer. The free surface of the fluid was tracked by volume of fluid (VOF) method. The fluid domain was regarded as a pseudo elastomer, then the structure-pseudo elastomer system was constructed. The multiphase fluid force at the fluid-solid interface was used as the excitation to solve the dynamical equations of the system to obtain the structural vibration displacements and the mesh deformations of the flow field. The fluid flow, structural deformation and the dynamic mesh were solved sequentially at each time step to solve the fluid-structure interaction problem. Based on the developed method, the fluid-structure coupling response of elastic baffle under the impact of dam-breaking flow was calculated. The motion behaviors of the free liquid surface of water and elastic baffle were obtained. The results show that the free liquid surface evolution and elastic baffle vibrational displacements are well in agreement with those of the existing algorithm, under the same mesh size, the method can reduce the computational time by 33.3% compared with the existing algorithms, under the impact of water flow, the elastic baffle is bent slightly to the impact side. Then the water rises along the left side of the baffle and forms a jet, and the baffle is bent greatly to another side. Finally, the amplitude of the baffle gradually decreases due to the damping of the fluid on both sides.

In order to study the effect of polymer microsphere profile control and flooding on produced fluid and deepen the understanding of the profile control and flooding mechanism of polymer microsphere, the produced fluid in typical blocks of major reservoirs such as ultra-low permeablity, super-low permeablity and low permeablity in Changqing oil field were analyzed and studied. After using gravity separation and centrifugal separation methods to obtain crude oil and produced water, the changes in the composition of crude oil group, K⁺, Na⁺, Ca²⁺, Mg²⁺, $\mathrm{SO}_{4}^{2-}$ ions, and water content in the produced water before and after profile control were analyzed, and the variation patterns were summarized. The results show that after injecting polymer microspheres into each typical block, the saturated alkane content in the crude oil decreases, the non-hydrocarbon content increases, the water content significantly decreases, and the salinity of the produced water increases. Through the above research, it has been further clarified that polymer microspheres mainly play a “blocking” role in reservoirs, and residual oil is utilized by expanding the swept volume of injected water, providing a theoretical basis for the production increase of Changqing Oilfield through profile control and flooding.

In order to clarify the depositional environment of the Upper Permian Wutonggou Formation, the Dalongkou section at the southern margin of the Junggar Basin was taken as an example, and the following understanding was obtained by analyzing the lithology, lithofacies types, lithofacies assemblages, and spatial spreading laws of anatomical section sands. Three types of eight gravel, sand, and mudstone phases capable of characterizing diagenetic sands in the Wutonggou Formation were summarized. Based on the lithofacies, four lithofacies assemblage types were further established, representing the point bar, the cross-bank breakout fan, and the fluvial sands, respectively. Through the analysis of the lithofacies combination of the section, the sedimentary subfacies of point bar, crevasse splay, and floodplain in the period of Wutonggou Formation can be further identified, and the sedimentary response model of meandering river with the change of lake level was established. The sedimentary facies and sand body distribution of underground reservoirs were clarified by the results of outcrop research.

The shale of Middle-Upper Permian in the Lower Yangtze area is an important source rock in the region, but the research on the elemental characteristics of different sedimentary facies is still lacking in the past. Continuous X-ray fluorescence(XRF) element scanning was performed on the shale core of the Middle-Upper Permian in Well Gangdi 1 in the Lower Yangtze Region. The contents of main elements such as Si, Al, Ca, Fe and trace elements such as Sr, Rb, Ti and their ratios in the middle and upper Permian strata were analyzed, and the evolution characteristics of sedimentary environment were discussed in combination with the quantitative analysis of mineral composition of samples. The results show that the elements such as Al, Ti, Si and Rb, which have strong indicative significance for terrestrial deposition, have a high-high-low variation in the vertical direction. The Ca, Sr and other elements indicating marine deposits are mainly concentrated in the upper Dalong Formation, and the content of other layers is low, and there are abnormal values in some areas. The ratio of element content has a certain rule, among which Rb/Sr and Ba/Sr show a low-high-low trend. The maximum value of Al/(Al+Fe+Mn) ratio is 0.8, the minimum value is 0.4, and the average value is 0.71, which is generally greater than 0.6, indicating an important source of biogenesis. The Middle-Upper Permian belongs to the transitional-marine reduction environment. From bottom to top, the sedimentary environment changes from deep-water basin facies to deep-water shelf facies to sea-land transition facies to shallow-water shelf facies. During this period, the water body changes from deep-shallow-deep. Among them, the early stage of the Gufeng Formation is the deep-water basin phase, and then gradually enters the deep-water shelf phase. The Longtan Formation is dominated by the sea-land transition phase, and the relative sea level changes frequently during the sedimentary period. In the deep-water period, the lithology is dominated by self-deposited limestone, and the corresponding element Ca content is high. In the shallow water period, it is mainly light gray mud shale deposition, and the corresponding main elements change to Si and Al. After the short-term subsidence of the sea level in the Dalong Formation, the water body gradually deepened, dominated by continental shelf deposition.

The Guocheng-Yazi area in the northeastern margin of the Jiaolai Basin is located in the southern section of the Muping-Rushan gold metallogenic belt. It is an important gold metallogenic area in the Jiaodong region. In recent years, medium-sized and large-scale gold deposits such as Pengjiakuang, Tudui-Shawang, Xijingkou, Liaoshang, Xilaokou, and Qianchuiliu have been successively explored. The cumulative amount of gold resources explored exceeds 180 t. Based on the field work of geological mapping, ore-bearing structure investigation, controlled source audio-frequency magnetotelluric sounding (CSAMT) and drilling engineering, the distribution of ore bodies, geophysical characteristics, ore-controlling structure and metallogenic regularity were analyzd. The western extension position of the Pengjiakuang detachment fault was preliminarily clarified. Extending westward from the Xijingkou to the Liaoshang to the Guocheng fault, which is the ore-controlling structure of Pengjiakuang, Xijingkou, Xilaokou, Qianchuiliu, Liaoshang and other gold deposits. The Queshan metamorphic core complex and its detachment faults are the main ore-controlling structures and favorable ore-forming spaces for gold mineralization in this area, and are important prospecting targets in future exploration and prospecting work. The mineralization depth of the gold deposit concentration area in this area is mainly 5.01~7.93 km, and the gold deposit has just been eroded as a whole. The deep and peripheral areas have good prospecting potential.

Affected by the continuous rainfall in the rainy season, the Taihe Town moraine soil paleolandslide is a giant soil-rock complex paleolandslide with a volume of about 1 200×10⁴ m³, which began to be resurrected in 2021 and entered the creep stage. By 2022, the growth rate began to decline in the rainy season, which seriously threatened the normal mining inside the pit. Based on field investigation, drilling exposure, field monitoring, and physical and mechanical tests, the influencing factors and resurrection mechanism of ancient landslides were explored on the basis of identifying the micro-topography, geological structure characteristics and deformation instability stages of ancient landslides. The results show that the accumulation of rock and soil and topography are the basis of ancient landslide resurrection, and rainfall infiltration and mining excavation are the inducing factors of landslide resurrection. The analysis shows that under the influence of long-term rainfall leaching, fine particulate matter accumulates at the base-cover interface to form a sliding zone, and mining excavation causes an effective free face at the leading edge. Under the long-term influence of groundwater, the strength of the sliding zone soil is gradually reduced. Rainfall leads to increased seepage and reduced shear strength, which induces the revival of ancient landslides. The research results have certain reference value for similar engineering problems.

To explore the effects of cardiac magnetic resonance imaging(CMRI) on the assessment of left ventricular function and myocardial changes in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). Thirty-one patients with OSAHS who were admitted to Handan Central Hospital from November 2019 to June 2021 were selected as the observation group, and 30 healthy volunteers who received CMRI monitoring during the same period were selected as the control group.Two sets of parameters related to left ventricular function were compared, including left ventricular ejection fraction (LVEF), left ventricular end diastolic/end systolic volume (LVEDV/LVESV), left ventricular myocardial activity imaging indexes[T1pre value(measurement of T1 relaxation time before enhancement) before mean injection of contrast agent in left ventricular myocardium, 15 min T1post value(T1 value of myocardial tissue measured by T1 mapping technique after using contrast agent in CMRI) and T2 value(transverse relaxation time of myocardial tissue)]after injection,and histological parameter characteristics of different myocardial layers[mean extracellular matrix volume fraction (ECV) of left ventricular myocardium].The left ventricular function parameters (LVEF, LVED) in the observation group are significantly lower than those in the control group, while LVESV and T2 values are significantly higher than those in the control group (P<0.05). There is no significant difference in T1pre, T1post, ECV in basal segment, middle segment and apical segment between the observation group and the control group (P>0.05).CMRI has a significant clinical effect in patients with OSAHS and can effectively assess the left ventricular function, structure and early myocardial lesions.

Due to the unique challenges of deep underground mining environments, such as frequent geological disasters like roof fall, rock bursts, and water inrush, there is a high demand for enhanced safety and stability in mines. The use of downward roadway backfilling methods has shown significant effectiveness in controlling ground pressure activities and rock layer movement. In light of this, the Chambishi Copper Mine in Africa was selected as a case study. Initially, a digital structural plane identification system was employed to conduct a detailed analysis of the ore body structural planes. The findings indicate that the development of structural planes in deep ore bodies significantly impacts the safe extraction of minerals. The high density and narrow spacing of these planes increase the fragmentation of the rock mass, elevating the risk of roof fall and instability in mining areas. Additionally, numerical simulations were performed to study the mechanical behavior and deformation characteristics of the deep zones of the Chambeshi Copper Mine. By optimizing the structure and strength of the bearing layers, the stability of the mining area can be effectively controlled. The simulation results demonstrate that well-structured bearing layers are capable of withstanding the pressure from overlying rock strata, ensuring higher stability in the mining areas. These research outcomes provide effective strategies for the safe extraction of minerals in deep mines, particularly in high-risk geological environments. Adaptable mining methods and safety measures were proposed, which were of significant importance for enhancing the safety and efficiency of deep mining operations.

The clustering of discontinuity orientation is crucial for revealing the distribution and characteristics of various types of discontinuities. Conventional clustering methods based on discontinuity pole density maps often rely on geological experience and lack objectivity. Therefore, the mean shift clustering algorithm was introduced to study the clustering of discontinuity orientation. Initially, discontinuity orientations with different degrees of dispersion were manually generated. Subsequently, these orientation data were converted into coordinates in 3-D space, and the sinusoidal value γ of the unit normal vector was employed as the similarity measure. The mean shift algorithm was then used to perform clustering analysis on the measured data set. Compared with the conventional pole density map method and the K-means clustering algorithm, the validity test index and clustering error recognition rate were close to those of the K-means clustering algorithm. Finally, taking the Chongqing Sangong rock slope as an example, the rationality and effectiveness of the new method were verified by field data. The results show that the performance of the proposed method surpasses that of the conventional discontinuity pole density map and K-means clustering algorithm. The clustering results are objective and reasonable, and the clustering effect for near-horizontal discontinuities is also satisfactory.

In order to efficiently develop the ultra-deep thin interbedded carbonate gas field, the development well of Lei-4 gas reservoir in western Sichuan gas field adopted a three-spud casing program. The first spud section was drilled into the Penglaizhen Formation to the third member of Xujiahe Formation. Due to the large variation of soft and hard sand mudstone, and the existence of mud shale or sand mudstone is easy to be hydrated and denudated, there will be falling block, collapse and other problems. The second spud section was drilled into the formation from the 3rd of Xujiahe Formation to Maantang Formation. The formation shale and coal seam are interbedded frequently, the uncased hole section is long and high pressure fractured gas layer, these factors are prone to risk of wellbore instability, well loss and even blowout. The third spud section was drilled into the fourth member of Leikoupo formation. Due to the alternations of limestone and dolomite, the stress difference between layers is large, and the formation is broken, it is easy to cause local instability of borehole wall, and even collapse, stuck drilling and other downhole complications. In the face of challenges, through theoretical research, laboratory experiments and field application optimization, potassium-based polysulfonic drilling fluid technology was used in the first section, the compound salt strongly inhibited polysulfonic anti-collapsing drilling fluid technology was used in the second spud section, strong plugging white oil base drilling fluid technology was used in the third section, have been formed to solve the technical problems faced by drilling fluids. The successful application of more than 10 wells has achieved remarkable results in speed and efficiency improvement..Among them, well PZ5-1D has a drilling depth of 8 208 m and a drilling cycle of 252.79 days.

Aiming at the problem of high water content and low degree of recovery of low permeability heavy oil reservoir in Guan128 block of Dagang Oilfield, the microscopic seepage law and residual oil characteristics of viscosity reducers flooding were studied through indoor experiments, and the planar wave and characteristics and residual oil distribution law were quantitatively analysed with the help of AI intelligent recognition. The experimental results show that after the viscosity reducer emulsification of crude oil, the emulsion aggregates and can block the water-driven flux channels, the advantageous transport channels of oil droplets increase, improve the wave and reach coefficient, and reduce the oil saturation. AI image identified pore throat droplets of oil, the wall membrane oil, the residual oil in the dead corner and the residual oil without wave and flake oil and other types of residual oil distribution, and the formation mechanism was analyzed, and measures of surfactants injection and encryption of the network of wells were put forward, and the blocking of high seepage channels was adjusted. Adding viscosity-reducing agent system can reduce the starting pressure gradient and improve the fluidity of heavy oil. After the conversion of water drive to chemical drive, the oil washing effect of residual oil in the pores and throat and residual oil in the dead space is improved, and the recovery rate is increased by 15.28%. The research results provide important theoretical reference for the research on the mechanism of efficient oil enhancement and field application of viscosity-reducing agent injection in the late stage of water-drive development of low-permeability heavy oil reservoirs.

CO₂ foam fracturing can reduce reservoir damage and contribute to the stimulation of unconventional oil and gas reservoirs. However, there needs to be more quantitative methods to evaluate the influence of the CO₂-H₂O ratio of foam fracturing fluid on the conductivity, and the optimization of foam fracturing fluid system is insufficient. To select the CO₂ foam fracturing fluid system suitable for the conglomerate reservoir in the Mahu Basin, proppant embedment experiments were carried out with the treatment of foam fluid with different CO₂-H₂O ratios at simulated reservoir conditions, and each interval of embedment depth was obtained. A conductivity model considering the heterogeneous proppant embedment was established to calculate the effects of different foam fluids on improving the conductivity and analyze its mechanism. The results show that using CO₂ to replace part of the water-based fracturing fluid can reduce the degree of proppant embedment. With the increase of the CO₂-H₂O ratio, the effect of improving the conductivity weakens and reaches the upper limit gradually, increasing by about 12% compared with that of water-based fracturing fluid. When the ratio is 7∶3, the conductivity of samples with low clay content (<20%) increases to the upper limit. However, the conductivity of samples with high clay mineral content (≥20%) is more sensitive to the influence of the CO₂-H₂O ratio, and the upper limit is lower. CO₂ foam fracturing fluid can improve the hydrological capacity of the propped fracture-formation system. The research results can reference the CO₂-H₂O ratio optimization of the CO₂ foam fracturing fluid system.

In the process of oilfield development, the formation of emulsion between crude oil and water is quite common, which increases the difficulty of crude oil treatment. The composition of crude oil, especially the precipitation of paraffin wax, has significant influence on the stability of the emulsion. From the unique perspective that the oil composition affects the phase change and then further determines the emulsion stability, a systematic study was carried out with the methods of emulsion stability test, oil-water interfacial characteristic test, wax precipitation test, asphaltene dispersion stability test, and microscopic observation. It is observed that increasing the amount of liquid paraffin in the solvents leads to a change in the form of wax crystals from fine particles to larger agglomerated wax crystals, and the asphaltenes dispersion stability decreases along with it. Test temperature can significantly affect emulsion stability. At 30 ℃, increasing the percentage of liquid paraffin reduces the interfacial tension, increases the interfacial dilatational modulus, and enhances the structure of the interfacial film. This contributes to the formation of small droplets and improves emulsion stability to a certain extent. At 15 ℃, by contrast, increasing the liquid paraffin content promotes the development of a more structured wax crystals network, which significantly enhances emulsion stability by binding water droplets. Additionally, it is also found that a wax crystal interfacial film could be formed at the surface of the emulsified drops, which improves further the interfacial film strength and emulsion stability. Based on the above findings, an influencing mechanism model is presented concerning the synergistic stabilization of model oil emulsion containing asphaltene and paraffin wax.

The problem of inaccurate evaluation of the clamping performance of the spiral angle type slip will be effectively overcome, which is caused by the unclear contact characteristics between the slip and the pipe string. The forces acting on the interaction between slip and columns were analyzed by the theoretical method. A full-scale finite element model of the interaction between the slip, pipe column, and slip seat was established using the numerical simulation method. The mises stress and contact stress distribution patterns of the slip and pipe column under different axial loads and friction coefficients were studied. The mises stress and contact stress gradually decreases from the bottom to the top in the axial direction. They are an imperfect symmetric distribution in the circumferential direction. And there are stress concentration locations. The slip is subjected to higher mises stress and lower contact stress than the pipe column. As the axial load increases, the mises and contact stress increase. As the friction coefficient increases, the mises and contact stress decrease. In design and practical use, emphasis should be placed on components and locations with high-stress levels. Under high load conditions, increasing the friction coefficient by changing the material and shape of the slip teeth is recommended. Further the clamping performance of the slip under high load conditions is improved. It also prevents damage to the pipe column caused by excessive clamping force. The research results can provide theoretical guidance for the design of slips and the evaluation of clamping performance.

In order to effectively reduce the erosion and wear rate of ordinary elbows and extend their service life. A stomach-type elbow was proposed, based on the theory of gas-solid two-phase flow, the Fluent software was used on the stomach-type elbow to numerically simulate and analyze fluid erosion characteristics. The analysis results show that the second circular cross-section position less than 7.5°, greater than 25.0° less than 40.0° of the gastric bend has an erosion-resistant effect, in which the second circular cross-section position of 35.0° of the gastric bend erosion-resistant effect is the best, compared with the ordinary elbow erosion-resistant performance increase by 9.88%. The flow rate increases from 8 m/s to 28 m/s, and the maximum erosion rate of the gastric bend and ordinary elbow at 35.0°, 37.5°, 30.0° and 32.5° increases by 26.08 times on average. The particle diameter increases from 45 mm to 120 mm, and the maximum erosion rate increases by 1.71 times. The mass flow rate increases from 0.02 kg/s to 0.12 kg/s, and the maximum erosion rate increases by 7.35 times. Mass flow rate increases from 0.02 kg/s to 0.12 kg/s, the maximum erosion rate increases by 7.35 times. Regardless of the flow rate, particle diameter, mass flow rate, 35.0°, 37.5°, 30.0°, 32.5° of the maximum erosion rate of the gastric bend is always less than the maximum erosion rate of the ordinary elbow, that is, all have the effect of anti-erosion, of which 35.0° of the gastric bend on the whole has the best anti-erosion effect. The elbow can effectively reduce the rate of erosion and wear to extend the service life of the pipeline, but also for the elbow of the anti-erosion structure design and optimization to provide a new design scheme.

To further improve the transmission performance of non-circular gear pair, a new helical non-circular gear with point contact was proposed based on the meshing principle of gears. Mathematical model of helical non-circular gear with point contact was constructed. Geometric kinematic relationships between the pitch curve and tooth profile curve for helical non-circular gear with point contact under spatial coordinate system were deduced. Tooth surface design of the gear was completed. Three-dimensional solid models of helical non-circular gear pair with point contact was established by using the convert-tooth shape method. The dynamic simulation model of helical non-circular gear with point contact was established. The dynamic meshing forces of the new gear pair and general involute non-circular gear pair under the same conditions were analyzed. Meshing characteristics of helical non-circular gear with point contact under different working conditions were also obtained. The tooth surface contact state and contact stress of point contact non-circular gear and involute non-circular gear under the same parameter and working condition were compared and analyzed. Research results provide an important theoretical support and reference value for the design and application of non-circular gear pair.

Fan nozzle is an important part of high pressure water descaling system, and its internal structure parameters directly affect the performance of jet. The nozzle flow field was analyzed by using fluid simulation software FLUENT, and the nozzle exit diameter, cone section contraction angle and exit contraction angle were selected as reference factors. The jet impact force was used as evaluation index, and the nozzle structure parameters were optimized by response surface method. The results show that the velocity distribution of the internal flow field is affected by the single factor of the diameter of the outlet section and the conical contraction angle, but the flow rate of the nozzle is little affected. The pressure drop of nozzle is affected by the change of the diameter of outlet section and the contraction angle of nozzle outlet, and the influence of the contraction angle of nozzle conical section on the pressure drop is negligible. When the diameter of the outlet section is 3.15 mm, the taper shrinking angle is 26.17°, and the outlet shrinking angle is 40.93°, it is found that the nozzle striking force is increased from the original 94.91 N to the optimized 143 N by establishing the outflow field and applying the gas-liquid two-phase flow model simulation calculation. The research results provide theoretical guidance for optimizing nozzle structure to enhance jet impact force.

In order to solve the technical problem of insufficient reliability and life of rotary seal under the coupling effect of high pressure and high speed and medium corrosion, experimental research on rotary lip seal was carried out, a high-speed rotary lip seal test bed with pressure was designed and built, leakage and friction torque characteristic tests of lip seal were carried out, simulation calculation of lip seal was carried out, and a new type of seal with low friction coating was innovatively proposed. The temperature rise and torque comparison test of traditional seal and spraying new seal at different speeds were carried out. The experimental results show that the lip spraying tetrafluoroethylene (PTFE) material can effectively reduce the temperature rise of the seal. When the rotational speed increases by 1 000 r/min, after reaching the heat balance temperature, the temperature rise of the spray lip seal is 2.4 °C lower than that of the traditional lip seal. Under the pressure condition, the temperature of the coated lip seal is about 3.48 °C lower than that of the traditional lip seal. Under the condition of high speed and poor lubrication, the temperature of the spray lip seal is about 4.61 °C lower than that of the traditional lip seal, but the sealing torque increases by about 0.03 N·m. The sealing performance is evaluated from two aspects of sealing temperature rise and sealing friction torque, which provides theoretical support for solving the technical problems of high parameter rotary seal.

Quality distribution detection is regarded as a crucial basis for regulating the rare earth extraction process. The variation of the lanthanum (La), cerium (Ce), praseodymium (Pr), and neodymium (Nd) solution system during the saponified P507-kerosene extraction is significant, showing obvious nonlinear characteristics such as time-varying and strong coupling. Moreover, the solution system exhibits no apparent color change. Existing soft measurement methods based on machine vision and artificial neural networks have shown unsatisfactory application effects. To address these issues, a mechanistic modeling method was first employed to construct a mathematical model for the quantitative analysis of the four components. Subsequently, by measuring the characteristic gamma-ray intensity information of the natural radioactive isotope ¹³⁸La@1.436 MeV (auxiliary variable), the mass distribution information of the four components (main variable) was predicted simultaneously. Finally, experiments were conducted based on a high-purity germanium detector. The results show that the minimum detectable mass concentration of La is 1.70 g/L. Compared with the experimental results, the relative errors of the predicted mass concentrations of La, Ce, Pr, and Nd are -3.11%~4.23%, -5.81%~3.74%, -8.16%~6.68%, and -19.87%~14.20%, respectively. The relative errors of the sensitivity prediction are 1.33%, 5.56%, -3.20%, and -0.41%, respectively. The proposed “gamma ray-soft measurement” method enables high-accuracy and high-sensitivity prediction of the four components La, Ce, Pr, and Nd. The detection process is not affected by changes in extraction system density, acidity, temperature, and other parameters, providing new technical references for rare earth extraction quality distribution detection.

At present, there are fewer studies on the macroscopic mechanical hysteresis model of magnetically controlled smart magnetorheological elastomer (MRE), which is not conducive to the application control of MRE materials. To improve the control effect of MRE materials, an experimental study on MRE’s magnetostrophic shear mechanical properties based on the Bouc-Wen model was conducted. The influence of magnetic field strength on the mechanical parameters of MRE was analyzed. Firstly, with the assistance of Simulink to establish the Bouc-Wen simulation model was established for MRE parameter fitting. Then, the stiffness, damping, and other material parameters were analyzed with the magnetic field strength change rule. Finally, through the experiments, the model validity was examined. The results show that with the increase of magnetic field strength, the parameters of MRE energy storage and energy consumption have different degrees of increase, in which the equivalent stiffness and maximum damping force increase significantly, respectively, increase 210.61%, 205.41%. In the range of 0.5~0.7 T magnetic field parameter growth rate is faster in the range of 0.7~1.0 T growth tends to be saturated. The dynamic mechanical properties of MRE are better described by the Bouc-Wen model, and the maximum error of the characteristic parameters is 4.42%. The research results can provide theoretical and experimental references for the optimal preparation and algorithmic control of MRE materials.

The rapid development of new energy vehicles has made the industry’s requirements for high-performance automotive motors continue to increase. Hybrid excitation motor is a new type of motor. The hybrid excitation motor combines the advantages of permanent magnet excitation and electric excitation, and has excellent regulation and reliability. A parallel claw-pole hybrid excitation motor structure was proposed. The magnetic circuit of the hybrid excitation motor was optimized by means of parallel axial excitation of permanent magnet and electric excitation device. On this basis, the parametric simulation of the thickness of the claw pole side plate and the large end of the excitation bracket of the motor was carried out respectively, and the average torque of the motor before and after optimization was simulated according to the optimal structure. Finally, the mechanical characteristic curves of the parallel claw-pole hybrid excitation motor and the permanent magnet synchronous motor were compared and analyzed. The results show that the parallel claw-pole hybrid excitation motor broadens the operating range of the motor by 17.24% on the basis of maintaining the torque performance, and improves the mechanical properties and adaptability of the hybrid excitation motor.

In order to mitigate the impact of wind power fluctuations on the power grid, a hybrid energy storage system (HESS) control strategy was proposed, which optimized the parameters of variational mode decomposition (VMD) using the mayfly algorithm (MA). Firstly, the sliding average algorithm was employed to determine the wind power grid connected power that met the grid standards. Then, a fitness function was constructed by combining two evaluation criteria, and the optimal parameters of the VMD algorithm were determined using the mayfly algorithm. The optimal parameters were then introduced into the VMD algorithm to decompose the hybrid energy storage power, realizing the initial allocation of the hybrid energy storage power. Finally, fuzzy control was utilized to optimize the state of charge (SOC) of the energy storage devices, adjusting the power commands of supercapacitors and lithium batteries. The results indicate that the proposed strategy not only enables adaptive decomposition and rational allocation of hybrid energy storage power, effectively mitigating wind power fluctuations but also ensures the SOC of the energy storage devices remains within a reasonable range, achieving safe and stable operation of the HESS.

The stability of power cyber physical system(CPS) is easily affected by stochastic uncertainty from both the information and physical sides. A stability analysis method for power CPS based on stochastic uncertainty model and a robust wide area feedback frequency control method were proposed. Taking into account the essential differences between the discreteness of the information side and the continuity of the physical side, as well as the mutual influence in terms of functionality, a dynamic model of power CPS in stochastic environment was established from both the information and physical sides. According to the definition of mean square exponential stability of stochastic differential equations, small signal stability analysis was conducted for dynamic model of power CPS. The critical variance based on mean square norm calculation was used to describe the impact of stochastic uncertainty on small signal stability of power CPS. Focusing on the norm optimization problem based on linear matrix inequality constraints, a robust wide area feedback controller was designed based on the distributed control method. Finally, simulation analysis was conducted on an IEEE 39 bus system, and the results verified the correctness and effectiveness of the proposed method.

Dynamic graph link prediction aims to predict the formation or disappearance of links between nodes in a graph based on their historical interactions. To address the issue of high energy consumption associated with modeling dynamic networks using recurrent neural networks at fine-grained temporal graphs, a dynamic graph link prediction model optimized by spiking neural networks was proposed. By the node memory updater incorporated spiking neural networks and the spiking update process of node memory, the evolving dynamics of dynamic graphs were learned by graph neural networks and the model achieved link prediction. The results on three publicly available classic datasets show that the proposed model exhibits improved runtime efficiency while maintaining accuracy, showcasing favorable performance in dynamic graph link prediction tasks.

In the contemporary digital healthcare setting, the dissemination and sharing of medical imagery are integral to routine medical operations. However, medical images often contain sensitive patient information, and without adequate protection, there is a risk of illegal acquisition or leakage, which brings unnecessary troubles. To address this issue, an encryption algorithm based on Zigzag scrambling and a new four-dimensional hyperchaotic system was proposed. Firstly, the Zigzag algorithm was used to scramble the image once, roughly hiding the obvious contours of the image. Then, an improved cat mapping algorithm was used to perform secondary scrambling on the image, removing obvious texture features. Finally, the scrambling factor generated from the plaintext image was applied to the initial value generation process of the hyperchaotic system. The generated hyperchaotic sequence was transformed into a hyperchaotic matrix for the subsequent diffusion process of the encryption algorithm. The simulation results show that the proposed algorithm can effectively conceal plaintext information based on the characteristics of medical images and resist common types of attacks. The robustness of the proposed algorithm has been demonstrated through testing, confirming its capability to address the issue of image interference in remote healthcare.

To solve the problem of insufficient extraction of sport features by dual stream networks in current action recognition, which leads to low recognition accuracy, a action recognition method based on sport feature enhancement two-stream networks was proposed to improve accuracy. The network was divided into spatial stream and temporal stream, with the same structure but different inputs. The input of the spatial stream network was a video frame sequence, while the input of the temporal stream network was a video frame difference sequence. The network structure used Resnet50 as the backbone network, replacing the 3×3 convolution with the proposed global sport feature module and local sport feature module, fully extracting video sport information, and finally combining spatial and temporal stream to output the results. The results show that the accuracy of the model on the UCF101 and HMDB51 datasets reaches 96.8% and 75.3%, which is superior to traditional algorithms.

In order to solve the problems of large training parameters and low text recognition rate of convolutional recurrent neural networks (CRNN) handwritten Chinese character recognition network model, a novel method for handwritten Chinese character recognition based on attention bi-directional long short-term memory network(AT-BLSTM) and knowledge distillation (KD) technology was proposed. By assigning different weights to the input vector features of AT-BLSTM network, the model training data set was more efficient and accurate. Through KD technology, the knowledge acquired from a large high-performance model was transferred to a small model, which ensured the accuracy of the model, reduced the training parameters and internal storage ratio, and obtained a lightweight training model with better performance. Through the comparison of multiple groups of experiments, the accuracy of Chinese character recognition is increased by 6.7%, and the training parameters are reduced by 15.94 M. The recognition accuracy of this network model reaches 97.9%, and the recognition effect of Chinese characters is better.

Remote sensing image target detection is one of great significance in military reconnaissance, intelligent agriculture and other fields, especially small target detection has been gaining continuous attention. However, small targets in remote sensing images face the problems of insufficient feature information and difficult detection, which have become the biggest obstacles plaguing the development of remote sensing applications. To this end, the you only look once-hybrid feature(YOLO-HF) algorithm was proposed, which introduced a hybrid attention mechanism of channel attention and self-attention in the network of the traditional YOLOv7 model to extract the target’s deep features, and fused the shallow and deep features to increase the richness of local features; to further strengthen the attention to the global information, a global attention mechanism was added for the small-scale targets after the extraction of the features, to achieve the ability of global feature expression enhancement. In order to avoid that the traditional loss function was sensitive to the positional deviation of small targets, which leaded to poor detection effect, a new metric was selected for use, which was embedded into the computation of the bounding box loss function, so as to accelerated the convergence of the loss function and realized the enhancement of the detection accuracy of small targets. The experimental results show that compared with the traditional YOLOv7 algorithm, the proposed algorithm shows superiority on both RSOD and NWPU VHR-10 datasets, and in particular, the mean average accuracy on RSOD dataset is improved by 2.90%, and the mean average accuracy on NWPU VHR-10 dataset realizes an improvement of 3.61%.

Accurately identifying the connecting handle of the train coupler is of great significance for the operation of the uncoupling robot. A train connection handle target recognition algorithm based on improved YOLOv5 was proposed to address this issue. The C_switchable atrous convolution(C_SAC) module was integrated into the backbone feature extraction network, and the wise intersection over union(WIOU) function was introduced as a new bounding box loss function to enhance the feature extraction ability of the backbone network, improve the model’s generalization ability and convergence rate. Then, images of the connecting handles of train couplers in different environments and positions on the production site were collected for recognition. The experimental results show that the improved YOLOv5 algorithm achieves a target recognition rate of 96.6% for the connecting handles of train couplers. Compared with the original algorithm, it shows significant improvements in accuracy, recall, average accuracy, and other aspects. Finally, it was applied in the development of an automatic uncoupling robot for train carriages, greatly improving the accuracy and effectiveness of automatic uncoupling.

In order to realize the automatic optimization of hyperparameters of YOLO model, the hyperparameter optimization of you only look once (YOLO) model based on orthogonal optimization strategy (OOS) was proposed. Firstly, based on the principle of statistical orthogonal test, the orthogonal search method of population and the hyperparameter contribution analysis strategy were proposed to improve the optimization efficiency of the algorithm. Then, the uniform orthogonal search strategy and the neighborhood orthogonal search strategy were designed to alleviate the problem of the YOLO model falling into the local optimum and premature convergence. Finally, YOLOv5, YOLOv5s-Transformer and YOLOv7 were used as optimization objects to test on two target detection datasets, NWPU VHR-10 and Pascal VOC. Test results show that the recognition accuracy of the YOLO model is improved by the OOS hyperparameter optimization method in all cases. The average recognition accuracy mAP@0.5 on two datasets is improved to 93.94%, 93.18%, 93.45%, and 85.81%, 84.59%, 89.96%. The mAP@0.5-0.95 is improved to 60.00%, 60.08%, 56.98%,and 62.27%, 58.89%, 70.77%. It can provide a new intelligent method for hyperparameter optimization of object detection model.

A lightweight and efficient two-stage video flame detection algorithm was designed to address issues of high false positive rates, poor adaptability, and low efficiency in complex scenes. In the first stage, an improved adaptive Gaussian mixture model (AGMM) was employed for rapid background modeling of video image sequences. Suspicious candidate regions were extracted from the sequences by leveraging the flickering and surging characteristics of flames. In the second stage, a residual deep normalization and convolutional neural network (ResDN) was used to discriminate these suspicious candidate regions. A simplified residual block was introduced to replace the original convolutional layers for a lightweight design, enabling accurate flame detection and localization. Compared with traditional classification algorithms, the proposed two-stage video flame detection algorithm effectively overcomes environmental interference in complex scenes, rapidly and accurately identifies flames, and demonstrates higher detection rates and adaptability.

Aiming at the problem of low tension control accuracy existing in the warp yarn tension control of carbon fiber corner link loom, a warp yarn tension control method considering the effect of beating-up was proposed. Firstly, the elongation of the warp yarn during beating-up was analyzed, and then a new tension control model of the warp feeding system was established by combining Hooke’s law with the existing tension model. Secondly, a command filter backstepping sliding mode controller was proposed, which estimated the first-order differentiation of the virtual control law through the filter to avoid the problem of “differential expansion”, and adopted the radial basis function(RBF) neural network to adaptively estimate the unmodeled part of the system, and at the same time, the sliding mode control was introduced to enhance the robustness of the system. Finally, MATLAB/SIMULINK software was used to carry out simulation experiments on the tension system. The results show that the filtered backstepping sliding mode control considering the effect of beating-up in tension control compared with the traditional backstepping sliding mode control in the case of similar response time, the stabilization time is shortened by nearly 16.3%, the amount of overshooting is reduced by 24.6%. Compared with the fuzzy proportional integral derivative(PID) control, the stabilization time is shortened by 51.7%, the amount of overshooting is reduced by 49.2%.

When utilizing double skin composite shear walls as the primary components for resisting lateral forces in buildings, it is crucial to ensure proper horizontal connection of the walls. Currently, traditional bolt connections and welding are the main methods used for horizontal connection of these walls. However, these methods present significant challenges during construction and do not fully exploit the structural advantages of the wall. Based on the structural characteristics of this type of wall, a new type of horizontal joint connection node was designed for the upper and lower layers of the wall. This new design featured a socket-type square semi-grouted sleeve connection. The influence of steel bar diameter, sleeve length, grouting material strength, and sleeve form on the tensile performance of this new connection node was explored using finite element simulation. The results indicate that this new node effectively connects the horizontal joints of double skin composite shear walls with several advantages including convenient construction and reliable performance. Furthermore, it is observed that failure mainly occurs on connecting steel bars which achieves an “equivalent cast-in-place” goal for prefabricated double skin composite shear walls.

In order to improve the engineering characteristics of silty soil in yellow plain area with low strength, easy deformation and poor bonding ability, mechanical testing and scanning electron microscope (SEM) were used to add different contents of xanthan gum(XG), The mechanical properties and improvement mechanism of XG, lignin fiber (LF) and curing age were studied. The results show that both XG and LF as improved materials can increase the compressive strength of silty sand. With the increase of XG content, the compressive strength of silty sand first increases and then decreases. With the increase of LF content, the compressive strength of silt will increase, and the improvement effect will be weakened by adding too much LF. When the two materials are added to the silt simultaneously, the compressive strength of the silt is higher than that of one material alone. XG produces high viscosity gel when it encounters water, the loose silty soil is tightly cemented together, and the strength of the soil is improved. LF contains large molecular groups, forming a spatial network structure with surrounding soil particles, which strengthens the joint force between soils. The research results can provide reference values for the silty soil subgrade improvement project in the yellow plain area.

In order to speed up the engineering progress, early strength additives are usually added to improve the early strength of cement grout. Calcium chloride, sodium sulfate, triethanolamine, synthetic calcium formate, HR-SA1 and other early strength additives were selected, the flowability, shrinkage rate, and compressive strength of cement slurry under the action of different early strength agents were explored through indoor experiments. In this way, the influence of different types of early strength agents on the early physical and mechanical properties of cement slurry were revealed. The results show that all early strength agents can meet the needs of on-site grouting requirements, ensuring that the fluidity of the cement slurry can be stable for a long time. The flowability of the synthesized calcium formate-based cement slurry significantly increases within 60 minutes, indicating a notable retarding effect. The fluidity of the other early strength agents cement slurry slightly increases within 60 minutes, but the amplitude is not significant. The compressive strength of (HR-SA1)-cement slurry specimens at all ages is significantly higher than that of ordinary cement slurry specimens, while the other four early strength agents have no significant effect on improving the compressive strength of cement slurry. The average shrinkage and shrinkage rate of (HR-SA1)-cement slurry specimens after final setting are very low, far lower than the average shrinkage and shrinkage rate of other early strength agent cement slurry specimens. It is verified by the construction site of prestressed anchor cable of a subway station in Qingdao City. The test values of the physical and mechanical properties of cement slurry are basically consistent with the results of laboratory test, which lays a foundation for the popularization and application of HR-SA1 early strength agent in practical engineering.

Microbial induced calcium carbonate precipitation (MICP) technology is an emerging green reinforcement technology for geotechnical engineering, which has a good application prospect in the reinforcement of loess slopes. The reinforcement of loess by MICP is affected by a variety of factors, in addition to the external environment, material properties and reinforcement methods and other factors, the calcium source, the concentration of binder, the age of the maintenance and the maintenance methods also play a decisive role in the microbial reinforcement of loess. The loess in Longxi area was taken as the research object, bacillus subtilis-induced calcium carbonate precipitation technology was adopted to consolidate loess, and a comparative experimental study on the shear strength of MICP-consolidated loess under the conditions of different calcium sources, binder concentration, age of maintenance and maintenance methods was carried out. The results show that the MICP technology is more effective in consolidating loess specimens when the calcium source is calcium chloride, the binder concentration is 1.0 mol/L and the specimens are cured for 7 d. The cohesion and internal friction are increased by 4.95 and 1.34 times, respectively, compared with the vegetal loess soil. The research results have certain reference value for the roadbed reinforcement and slope management in the Loess Plateau area.

In order to investigate the durability of fibergypsum-based cementation material, a composite material was prepared byincorporating polypropylene and ramie fibers into high-strength gypsum,fly ash, and slag in a ratio of 44:34:22. Sodium methylsilicate wasutilized for waterproofing the fiber gypsum-based cementitious material,and the effects of freeze-thaw cycles on its softening property, waterabsorption, and mass loss were studied after 5,15,25,45, and 90 daysunder the combined action of ${\mathrm{H}}_{2}{\mathrm{{SO}}}_{4}$ or $\mathrm{{NaOH}}$ corrosion andfreeze-thaw. Freeze-thaw strain testing, flexural and compressivestrength testing, as well as industrial computed tomography(CT) scanningwere conducted. The results indicate that fibers can mitigate bothelastic and plastic deformation of the gypsum-based cementitiousmaterial during freeze-thaw cycles. Furthermore, under the combinedeffect of acid-base corrosion and freeze-thaw cycles, NaOH causesgreater damage than ${\mathrm{H}}_{2}{\mathrm{{SO}}}_{4}$ does.After undergoing 90 days of freeze-thaw cycling with sodiummethylsilicate treatment applied to it, the flexural and compressivesoftening coefficients increase by 0.28 and 0.13 respectively comparedto specimens without waterproofing; meanwhile water absorption ratesdecrease by 1.56% while mass loss rates decreased by 9.52%. Asfreezing-and thawing times increase, pore development in specimens isstill dominated by small holes, and crack diameters are mainly between ${0.1}\sim 2\mathrm{\;{mm}}$ .

In order to investigate the durability of fiber gypsum-based cementation material, a composite material was prepared by incorporating polypropylene and ramie fibers into high-strength gypsum, fly ash, and slag in a ratio of 44∶34∶22.Sodium methylsilicate was utilized for waterproofing the fiber gypsum-based cementitious material, and the effects of freeze-thaw cycles on its softening property, water absorption, and mass loss were studied after 5, 15, 25, 45, and 90 days under the combined action of H₂SO₄ or NaOH corrosion and freeze-thaw. Freeze-thaw strain testing, flexural and compressive strength testing, as well as industrial computed tomography(CT) scanning were conducted. The results indicate that fibers can mitigate both elastic and plastic deformation of the gypsum-based cementitious material during freeze-thaw cycles. Furthermore, under the combined effect of acid-base corrosion and freeze-thaw cycles, NaOH causes greater damage than H₂SO₄ does. After undergoing 90 days of freeze-thaw cycling with sodium methylsilicate treatment applied to it,the flexural and compressive softening coefficients increase by 0.28 and 0.13 respectively compared to specimens without waterproofing; meanwhile water absorption rates decrease by 1.56% while mass loss rates decreased by 9.52%. As freezing-and thawing times increase,pore development in specimens is still dominated by small holes,and crack diameters are mainly between 0.1~2 mm.

Understanding the failure mechanism of cracked rock mass under the general stress state is essential for underground engineering construction safety. A series of true triaxial fracture tests on the sandstone with single pre-existing flaw were conducted. The failure modes of the cracked sandstone were analysed, and the multi-scale fracture characteristics and mechanisms of the basic types of crack were identified. Moreover, the influences of the stress state and the pre-existing flaw on the rock failure mechanism were summarized. The results indicate that the rock failure mode is controlled by the true triaxial stress and the pre-existing crack. Based on the multi-scale fracture characteristics, the fracture mechanism of the crack. The rise of minimum principal stress σ₃ can significantly reduce the percentage of the shear crack, while the rise of intermediate principal stress σ₂ conduces to the increase of the percentage of the tensile crack. The pre-existing flaw has a certain promoting effect on the initiation of the tensile crack, however, the true triaxial stress is the decisive factor controlling the rock failure mechanism.

In order to improve the traffic efficiency of aircraft routes in areas affected by strong convective weather and optimize the diversion path of aircraft under the influence of strong convective weather, a multi-objective diversion path planning method based on the non-dominated sorting genetic algorithm III(NSGA-III) was proposed. By constructing a flight environment model and delineating flight restricted areas according to airspace conditions, and on this basis, focusing on the impact of strong convective weather in the area where the aircraft was diverted, the aircraft operation cost was the lowest, the diversion angle was the smallest, and the non-linear coefficient was the smallest, with the goal of minimizing the impact of weather, using NSGA-III to comprehensively considered factors such as safety and economy and other factors, a multi-target diversion plan for a certain airspace route under severe convective weather was carried out, and simulation analysis was conducted. The research results show that NSGA-III can comprehensively consider the four proposed goals and calculate multiple effective alternative diversion paths. Under the conditions of selecting two diversion points and taking into account the economy and rationality of the operation while ensuring the safe operation of the aircraft, a total of 91 alternative routes are available.

In order to analyze the influence of evolution of the dominant order of wheel polygonal wear on the vibration response of the train-bridge coupling system, the key influencing factors and evolution patterns of the dominant order of polygon wear were summarized first. Meanwhile, the coupled dynamic model of the train-bridge system was established by utilizing a combined simulation approach with ANSYS and SIMPACK. Subsequently, the impact of evolution of the dominant order of wheel polygonal wear on the vibration response of the train-bridge coupled system under different operational mileages, train operating speeds, vertical stiffness of fasteners, and variations in wheel diameter, was explored. The research results indicate that the evolution of the dominant order of wheel polygonal wear significantly affects the dynamic response of the train-bridge coupled system. In general, when the wheels experience high-order polygonal wear, the lateral and vertical accelerations at the mid-span of the bridge increase significantly. Moreover, the wheel-rail force and derailment coefficient also increase significantly, with the train wheels experiencing momentary bouncing. This has an impact on both the quality of high-speed train operation on the bridge and the safe operation of the bridge structure, necessitating timely wheel re-profiling.

In order to investigate the feasibility of applying solidified shield muck in road construction, the shield muck from Nanjing Metro was taken as the research object, and the green polymer composite curing agent developed independently was used to solidify the shield muck. The impact of the curing agent dosage and maintenance age on the road performance indicators of the shield muck was analysed using various tests-unconfined compressive strength, direct shear test, California bearing ratio (CBR), resilient modules, and freeze-thaw cycle test. In addition, the micro-characteristics and solidification mechanism of the solidified soil were investigated by scanning electron microscope and X-ray diffraction. The results indicate that the composite curing agent can effectively improve the strength of solidified muck, and with the increase of curing agent dosage and maintenance age, the strength of solidified muck also increases. The CBR and resilient modulus of solidified shield muck substantially improve as the dosage of the curing agent elevates, and the solidified soil can well meet the requirements of the Specifications for Design of Highway Subgrades (JTG D30—2015) and Specifications for Design of Highway Asphalt Pavement (JTG D50—2017). The freeze-thaw resistance of shield muck is poor, while it can be effectively improved after curing treatment. The strength loss and mass loss of solidified soil are less than 20% and 1% respectively. The anti-freezing performance indicators meet the requirements of the specification. After the curing agent has been added to the soil body, the polymer components will absorb water and dissolve, creating a static chelating effect with the mineral ions in the soil, initially reducing the water content of soil and promoting the agglomeration between the soil particles. Meanwhile, the other components of the curing agent generate hydration reaction to form hydrated calcium silicate gel, ettringite and other substances to fill the internal pores of soil, making the soil structure denser and greatly improving the strength.

To explore the reasonable lining section thickness of shallow buried soft soil excavation channels under vehicle loads, two-dimensional finite element models were established using load structure method and strata structure method, respectively. The stress characteristics and safety factors of subway excavation channels under different burial depths, vehicle loads, and lining thicknesses were quantified. The research results indicate that regardless of the presence or absence of vehicle loads, the maximum bending moment of the tunnel is located at the arch foot or arch shoulder, and the minimum safety factor is located at the arch crown. According to the original design reinforcement, regardless of whether there is vehicle load, the safety factor decreases with increasing burial depth and increases with increasing secondary lining. Under shallow burial conditions, the safety factors calculated by the load structure method are smaller than those calculated by the stratum structure method. The calculation results of load structure method show that under vehicle load and surrounding rock pressure, the secondary lining thickness is 60, 90, 100 cm respectively, and the burial depth does not exceed 8, 12, 14.6 m respectively, meeting the safety factor requirements of the specifications. The calculation results of the stratum structure method show that under vehicle load and surrounding rock pressure, when the thickness of the secondary lining is 60, 80, 100 cm respectively, its burial depth does not exceed 12, 15.5, 19 m, which can meet the safety factor requirements of the specifications.

In response to the shortcomings in the construction of temporary support for tunnels, a assembly of temporary support was proposed, and the new structure was studied from the aspects of temporary support shape, assembly structure, and stress deformation. Taking the Shaojiatang Tunnel as the background, on-site monitoring data was collected and compared with traditional temporary support structures using finite element software. It can be concluded that excavation of the tunnel’s rear tunnel will have adverse effects on the deformation of the previous tunnel. Vertical temporary support has better control over the left and right arch waists, surface settlement, and total convergence deformation of the tunnel. Compared with traditional curved structures, it decreases by 16%, 20%, 55%, and 14%, respectively. Moreover, vertical temporary support can restore stability faster and shorten the dismantling distance. By using vertical temporary support, the initial support force of the tunnel is smaller and safer compared to the curved support, and the maximum vertical and lateral stresses are reduced by 58% and 73%, respectively. The mechanical characteristics of temporary support local structures were simulated using ABAQUS software. The results show that the forces and deformations of both prefabricated vertical and traditional temporary support structures can meet the requirements of the specifications. However, prefabricated temporary support structures have more advantages in construction efficiency and economic benefits, and choosing prefabricated temporary support is more suitable.

In order to facilitate the counting of turning traffic flow and to enhance the detection speed and accuracy of turning traffic flow at intersections, a deep learning-based method was suggested for detecting, tracking, and counting turning traffic flow at urban crossings. Initially, the YOLOv5s, which was lightweight and efficient, was chosen as the target detection framework after conducting a comparative analysis. Unmanned aerial vehicle (UAV) aerial photography was utilized to record video footage of traffic movement at urban intersections, resulting in the development of a dataset of vehicle aerial photography photos. The pre-training weights and the most recent weight files were utilized to conduct training and testing on the self-constructed dataset. The model evaluation shows that the vehicle detection model using YOLOv5 exhibits great detection speed and accuracy. The model’s box_loss value declines rapidly and stabilizes at 0.038, while the mAP_0.5 value climbs swiftly and stays near 0.91.After that, the DeepSORT model was used as the backend multi-vehicle tracking technique, and a corner-to-centroid coordinate transformation was used to simplify the extraction of vehicle trajectories. The precision of the driving trajectory line was evaluated thereafter. To improve the robustness of trajectory points’ coordinate information, a corner-point-center-of-mass point coordinate transformation was suggested to tackle the issue of corner points in the detection frame. A sixth-degree polynomial was used to model the vehicle trajectory. Unsuitable trajectory lines were rotated and optimized to meet the function mapping requirements and ensure good fitting of all trajectories. Turning vehicles were detected and counted by using a predetermined threshold to determine the turning angle. Ultimately, to validate the performance of the proposed turning vehicle flow detection method, vehicle detection experiments were conducted at a city intersection as an illustration. The manual counting values were compared and analyzed against the detection results obtained using this method. The results show that the average detection accuracy for the four flow directions is 92.9%, with a maximum of 95.7%, meeting the standard detection requirements for turning vehicle flow in real intersection scenarios.

In order to study the influence of the tank environment on the results of the seaplane model test, for the first time in this field, a series of whole aircraft model tests were conducted using the same seaplane model in two towing tanks to study the aerodynamic and hydrodynamic characteristics of the whole aircraft model in the two towing tanks, the test results and environmental differences were analyzed. The results show that the towing tank environment has a significant impact on the aerodynamic characteristics of the seaplane model, but by compensating the aerodynamic characteristics of the seaplane model in each towing tank during the test, the interference of the test environment on the water resistance results could be avoided, so as to obtain a more satisfactory water resistance test result. Among the boundary effects of the towing tank, the blockage effect has the greatest impact on the aerodynamic characteristics of the seaplane model. Compared with 2.51% relative blockage ratio 0.67%, the aerodynamic drag coefficient of the seaplane model is 0.1~0.2 larger, and the lift coefficient is at least 0.2.Because the typical high-speed coasting state is used for aerodynamic compensation to calculate, so the compensation effect is only achieved at the corresponding speed and produce some deviation at other speeds, resulting in a certain deviation in the test result, but it will not have a significant impact on the test result because the deviation is so small. The research findings provide guidance for model hydrodynamic tests and performance analysis of seaplanes in China.

According to the requirements of rain ingestion of airworthiness regulations, the rain ingestion calculation was carried out for the no booster fan part. The movement trajectory of water droplets with different water speeds was studied based on Lagrangian particle tracking, and the separation amount of water droplets ingested to inner duct was obtained. Further more, the requirements for water spray speed from the rain ingestion test rig in the certification for turbofan engine was discussed,which can support the design and verification of rain ingestion airworthiness of turbofan engine. The results show that with the decrease of water speed, the amount of rain impacting on the fan blade and other walls increases, and no water droplets can pass through the fan blade and enter the inner duct. The water entering the engine inner duct at 250 m/s is 15.3 percent of the total amount of water, about 19.1 times of that at 10 m/s. Under the same water velocity, as the distance between the splitter and the fan blade decreases, the increase in water ingested to inner duct increases. At different fan rotational speeds, the change trend of the water ratio ingested to inner duct with initial water velocity is consistent, basically increasing with the increase in water drop velocity, and then remaining or slightly decreasing.

In order to cope with the rapid recovery and growth of air passenger flow and the uncertainty of passenger group structure and consumption behavior, and to give full play to the role of aircraft parking stands resources in improving non-aeronautical revenue, an optimal allocation model for aircraft parking stands based on the maximization of flight route commercial value was established. Firstly, the game theory combinatorial weighting method was used to correct the influence of subjective factors on the evaluation results. Then, the commercial value of aircraft parking stands and flight routes was quantitatively ranked by the VlseKriterijumska optimizacija I kompromisno resenje(VIKOR) algorithm, which could eliminate the mutual influence of multiple indicators. Finally, a trunk airport in northern China was used as an example to verify the feasibility of the method. The results show that three evaluation indicators of commercial value of flight routes are significantly correlated with the per customer transaction at boarding gate and commercial concentration zone, including departure time, dwell time and daily average passenger volume. By reasonably matching flight routes and parking stands based on commercial value, the commercial value of boarding gate and commercial concentration zone can be increased by 9.4% and 6.2% respectively. Therefore, introducing the commercial value of flight routes into the traditional aircraft parking stands allocation model has important practical application value for increasing airports non-aeronautical revenue.

Predicting the emission reduction potential and cost of sustainable aviation fuel (SAF) that aligns with China’s national conditions is essential for advancing the SAF industry and achieving carbon neutrality goals. Based on the principles of international comparability and independent controllability, a lifecycle carbon emission reduction model was developed for two technological pathways: hydroprocessed esters and fatty acids (HEFA) and Fischer-Tropsch (FT). This model forecasted the emission reduction and cost associated with SAF in China’s civil aviation sector from 2025 to 2060.The results indicate that the HEFA pathway, which is suitable for implementation between 2025 and 2030 using waste oils as feedstock, achieves a carbon emissions reduction of 61.3 kgCO_2e/GJ, contributing to an overall reduction of 84.4%. This associated cost ranges from 0 to 1 025.9 CNY/tCO_2e when compared to traditional aviation kerosene. In contrast, the FT pathway-primarily developed between 2030 and 2060 utilizing municipal solid waste as raw material yields the highest carbon emissions reduction at 68.4 kgCO_2e/GJ. Furthermore, routes employing agricultural or municipal solid waste exhibit lower abatement costs than those utilizing forestry waste. Considering China’s specific national conditions, it is determined the FT route utilizing agricultural waste as feedstock is more appropriate for development as the main SAF production technology after 2030 due to its abundant raw materials and comparatively lower abatement costs. Projections suggest that by 2060, reductions in China’s civil aviation SAF could reach approximately 17 177 million tons to 19 819 million tons. From a possible scenario spanning from 2025 to 2060, it is estimated that cumulative carbon abatement costs will amount to between 11 063 to 45 828 billion CNY, this corresponds with a marginal carbon abatement cost ranging from 220 to 697 CNY/tCO_2e.

To explore the formation mechanism of safety working style among flight cadets, a hypothetical model was constructed based on the theory of planned behavior, incorporating organizational safety culture as an extended variable. Six questionnaires, including behavioral attitude, subjective norms, perceived behavioral control, behavioral intention, safety working style and organizational safety culture, were compiled and distributed to 160 flight cadets. The feasibility of the theoretical model was analyzed through direct path effects, indirect path effects, and moderation effect analysis. The results indicate that the behavioral intention of flight cadets has a significant positive impact on their safety working style. Behavioral attitude, subjective norms, and perceived behavioral control influence safety working style primarily through behavioral intention. Additionally, subjective norms and perceived behavioral control can indirectly enhance behavioral intention through behavioral attitude, ultimately leading to a positive impact on safety working style. Furthermore, organizational safety culture plays a positive moderating role in the impact of behavioral intentions on flight cadets’ safety working style. These findings give new perspectives that it is significant to enhance flight cadets’ strong sense of safety responsibility, impose strict adherence to regulations and foster the integration of safety culture within civil aviation institutions which could effectively elevate their safety working style and ultimately ensure flight safety.