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Space gravitational wave detection drag-free control has many degrees of freedom, complex control mode, high accuracy requirements, and ground-based simulation of all degrees of freedom and controller verification experiments are challenging due to complexity. To simulate selected degrees of freedom on the ground, a drag-free control semi-physical simulation platform is designed, which emulates space satellite motion and two test masses arranged at a 60° angle. According to the physical model of the system, a disturbance resistant drag-free controller is designed based on H∞. The drag-free control validation experiments are carried out on the built semi-physical simulation experimental platform, and the results verify the characteristics of the controller. Thus, the effectiveness of the proposed drag-free control algorithm is verified, and the H∞ controller demonstrates superior control performance compared to the PID controller.

The Bozi-Dabei Block is currently one of the main blocks for increasing reserves and production in the Tarim Oilfield. However, the remaining trap scale in this block has decreased, and the situation of gas reservoir water invasion is severe. It is urgent to study the mechanism and distribution characteristics of micro faults. This study is based on seismic, logging, and geological data, starting from the differences in regional tectonic evolution in the Bozi-Dabei area, and analyzing the differences in segmented deformation of control ring faults. Focusing on typical gas reservoirs, analyze the structural, sedimentary response characteristics, and seismic reflection characteristics of micro faults, establish a set of micro fault identification and prediction methods, comprehensively analyze the results of structural analysis, sand box physical simulation, and geophysical interpretation, clarify the main controlling factors of micro fault development, analyze the development laws of micro faults, and based on this, analyze the structural, sedimentary response characteristics, and seismic reflection characteristics of micro faults, and preliminarily establish a set of micro fault identification and prediction methods. Finally, fine fault identification and prediction were carried out on key gas reservoirs, and the results showed that this method can effectively identify and clearly characterize fine faults inside the gas reservoir.

The high stability and tightness of modern aviation hydraulic pipelines require them to have a very low leakage rate under variable pressure environments. Once the leakage of the hydraulic pipeline is likely to cause an irreversible air disaster. Flaring straight pipe joint is one of the most widely used in aircraft hydraulic pipelines. The establishment of the simulation model is an effective method to accurately predict the annular gap leakage of the pipe joint. The ring gap of the pipe joint is located inside the threaded sleeve, which cannot be directly observed. The existing leakage prediction methods usually only focus on the microscopic interface contact and ignore the leakage prediction of real complex structures. Therefore, this article is based on ideas, semi-physical simulation through experimental data calibration tightening torque and annular gap width and the mathematical relationship between void ratio, and then established the flaring type straight pipe joint circular aperture leakage prediction simulation model, the ability to different tightening torque and hydraulic pressure conditions for predicting the pipe joint leakage rate, finally, the simulation experiments have been carried out to verify prediction model, The validity of this method is proved.

To gain a deep understanding of the interaction between underground mining and mountain deformation, based on historical deformation and the UAV video, we analyzed the evolution process of deformation and failure in detail and comprehensively evaluated the slope deformation and fracture network under the action of underground mining via the bottom friction physical simulation test, DPDM technology, fractal theory, and percolation theory. We simulated the whole process of mining, deformation, and failure of the Pusa collapse. DPDM technology was employed to obtain the evolution process of the total displacement, maximum shear strain (γmax), and volumetric strain εv of the Pusa collapse and establish a relationship between the fractal dimension and settlement. Simultaneously, the fractal dimension, fracture number, fracture rate, and percolation probability of the fracture network were calculated in MATLAB software. The research results of the bottom friction physical simulation test and DPDM technology indicated that after the M10 coal seam was mined, the maximum total displacement and maximum shear strain γmax were mainly located in the direct roof, resulting in volume expansion due to the direct roof collapse. After the M14 coal seam was mined, the maximum total displacement and volume strain εv developed towards the slope top, and the maximum shear strain was located in the middle and lower parts of the model surface and the leading and trailing edges of the slope top, respectively. The research results of fractal dimension and percolation probability indicated that after the M10 coal seam was mined, the development form of the fracture network at this stage mainly entailed the formation of new fractures. After the M14 coal seam was mined, the fracture network developed from beyond this stage mainly included fracture expansion and opening. The test results are consistent with the historical change process and the UAV video showing the method and signs of deformation. These research results help to better explain the deformation evolution process of a given slope under the action of underground mining and provide a technical reference for accurate assessment and proper mitigation of similar landslide disasters.

In recent years, near-field networks have become a vital part of smart grids, raising growing concerns about their security. Studying threat evolution mechanisms is key to building proactive defense systems, while early identification of threats enhances prediction and precision. Unlike traditional networks, threat sources in power near-field networks are highly dynamic, influenced by physical environments, workflows, and device states. Existing models, designed for general network architectures, struggle to address the deep cyber-physical integration, device heterogeneity, and dynamic services of smart grids, especially regarding physical-layer impacts, cross-system interactions, and proprietary protocols. To overcome these limitations, this paper proposes a threat evolution framework tailored to smart grid near-field networks. A novel semi-physical simulation method is introduced, combining traditional Control Flow Graphs (CFGs) for open components with real-device interaction to capture closed-source logic and private protocols. This enables integrated cyber-physical modeling of threat evolution. Experiments in realistic simulation scenarios validate the framework’s accuracy in mapping threat propagation, evolution patterns, and impact, supporting comprehensive threat analysis and simulation.

The exploitation of ultradeep, fractured, and low-porosity gas reservoirs often encounters challenges from water invasion, exacerbated by the presence of faults and fractures. This is particularly evident in the Kelasu gas reservoir group, located in the Kuqa Depression of the Tarim Basin. The complexity of the water invasion patterns in these reservoirs demands a thorough investigation to devise effective water control measures. To elucidate the water invasion patterns, a combined approach of large-scale physical modeling and discrete fracture numerical simulations was adopted. These models allowed for the identification and categorization of water invasion behaviors in various gas reservoirs. Furthermore, production dynamic analysis was utilized to tailor water control strategies to specific invasion patterns. The large-scale physical simulation experiment revealed that water invasion in gas reservoirs is primarily influenced by high-permeability channels (faults + fractures), and that the gas production rate serves as the key factor governing gas reservoir development. The range of gas extraction rates spans from 3% to 5%. As the gas extraction rate increases, the extraction intensity diminishes and the stable production duration shortens. On the basis of the changes in the water breakthrough time and water production rate, a 2% gas extraction rate is determined as the optimal rate for the model. The embedded discrete fracture numerical simulation model further supports the findings of the physical simulation experiments and demonstrates that ① this type of gas reservoir exhibits typical nonuniform water invasion patterns, controlled by structural location, faults, and degree of crack development; ② the water invasion patterns of gas reservoirs can be categorized into three types, these being explosive water flooding and channeling along faults, uniform intrusion along fractures, and combined intrusion along faults and fractures; ③ drawing from the characteristics of water invasion in various gas reservoirs, combined with production well dynamics and structural location, a five-character water control strategy of “prevention, control, drainage, adjustment, and plugging” is formulated, with the implementation of differentiated, one-well, one-policy governance. The study concludes that a proactive approach, prioritizing prevention, is crucial for managing water-free gas reservoirs. For water-bearing reservoirs, a combination of three-dimensional water plugging and drainage strategies is recommended. These insights have significant implications for extending the productive lifespan of gas reservoirs, enhancing recovery rates, and contributing to the economic and efficient development of ultradeep, fractured, and low-porosity gas reservoirs.