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.

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.

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.

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.

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.

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.

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.

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.

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.

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.