The identification of aviation accident risk factors through the system-theoretic process analysis(STPA) method is a qualitative analysis process that does not allow for a quantitative assessment of the extent to which each factor contributes to an accident. To address the above problem, a qualitative and quantitative analysis method combining STPA and Bayesian network (BN) was proposed. Taking the JetBlue A320 aircraft flap accident as an example, the control structure model of the flap control system was constructed by STPA method, and the potential unsafe control behaviors and related causal scenarios were analyzed comprehensively. Then, the results of STPA qualitative analysis were transformed into a Bayesian network model that could be quantitatively analyzed, so as to identify the internal interaction logic and the highly influential factors in the accident, and put forward comprehensive safety recommendations. The analysis results show that the main factor leading to the accident is the failure of hydraulic source, while the failure of power transmission unit (PTU) and the leakage of hydraulic line are the main causes of hydraulic source failure, with a critical importance of 0.688 and 0.299, respectively.

To investigate the stress characteristics of the primary support in the shallow buried biased section of the tunnel in fully weathered granite strata. Based on the Xiangsishan Tunnel, laboratory tests were conducted to determine the mechanical parameters including cohesion and internal friction angle of fully weathered granite. The construction process was simulated by FLAC 3D numerical software for the shallow buried bias section of the tunnel entrance. To study the effects of varying ground slopes, tunnel depths, and soil-rock interface locations on the stress characteristics of the primary support structure. The results indicate that, under various impact factors, the axial force and bending moment of the primary support exhibit the distribution characteristics of “upper large and lower small”, while the safety factor displays the opposite trend. The internal stresses of the primary support are distributed asymmetrically as the ground slope increases. The positive bending moment shifts toward the deeper-buried side and gradually increases, while the negative bending moment and axial force increase at the arch waist on the shallow-buried side. When the ground slope reaches 40°, the safety factor of the primary support falls below the standard allowable value. However, the stability of the primary support can be enhanced by implementing multi-stage variable slopes. As the depth of the tunnel increases, the asymmetric distribution of internal stresses in the primary support decreases, while the overall magnitude of internal stresses continuously increases. When the soil-rock interface crosses the tunnel at various locations, the magnitude of the internal stresses in the primary support is significantly affected, whereas the distribution pattern remains relatively stable. The reliability of the stress characteristics of the primary support under various impact factors was verified through on-site monitoring of the stress variations in the steel arch and concrete at various locations of the tunnel.

The optimization and operational control of ventilation systems on the offshore platforms is of great significance for improving cabin environmental quality and ensuring occupant health. In response to the current lack of a comprehensive design standard system for offshore platform ventilation, domestic and international specifications for shipboard and land-based ventilation systems were systematically classified and summarized to establish a dedicated design standard framework tailored to offshore platforms. Ventilation rate models, indoor dynamic models, air quality models, and energy consumption models were analyzed. Furthermore, an overview of ventilation optimization methods was provided for three critical areas: living areas, equipment areas, and storage areas. Current challenges and technical difficulties in system design and operation were analyzed, and feasible future development strategies for ventilation system design and optimization were proposed. The research results provide scientific basis and technical guidance for the design, operation, and energy-saving measures of offshore platform ventilation systems.

To mitigate the risk of annular pressure buildup caused by solid-phase deposition in the B and C annuli of deep-water wells, experimental tests were conducted on sedimentation behavior using common deep-water drilling fluid systems. The sedimentation height and post-settling solid-phase permeability of various drilling fluids were measured. Based on the parameters of solid phase percolation characteristics, and considering the impact of annular fluid solid deposition, a predictive analytical method was established for annular pressure under percolation conditions. Case analysis was conducted to validate the approach. Results show that the sedimentation height follows the order: oil-based drilling fluid > EZFLOW drilling fluid > HEM drilling fluid. In contrast, the post-settling solid-phase permeability is ranked as EZFLOW drilling fluid > HEM drilling fluid > oil-based drilling fluid, with a maximum permeability of 2.216 μm². Under annular fluid solid-phase deposition conditions, reductions in annular fluid viscosity, increases in formation permeability, and longer open-hole cement sheath sections reduce fluid viscous resistance, enlarge the seepage contact area with the formation, and enhance fluid flow. Therefore, reducing drilling fluid viscosity and extending the open-hole cement sheath length can improve the pressure release capacity in the B and C annuli of deep-water wells. However, the presence of solid-phase deposition significantly restricts seepage flow rates compared to conditions without deposition, leading to a potential risk of incomplete pressure relief following solid-phase sedimentation.

In order to study the problem that the processing of 7075 aluminum alloy rings was affected by the large value of initial residual stress, the effect of reducing the residual stress was investigated by using the method of compression of 7075 aluminum alloy rings along the ring direction. ABAQUS simulation software was used to simulate the quenching and compression of 7075 aluminum alloy rings to obtain the initial residual stress field and the residual stress field after compression. The results show that the initial residual stresses generated by quenching can be effectively reduced by the method of compression in the ring direction. After the data before and after compression is compared, it is found that when the compression deformation amount is 1.312 5%, the amplitude of quenching residual stress decreases by 57% of the original residual stress value as a whole, and the amplitude of radial residual stress and circumferential residual stress decreases by about 58%. It is concluded that the method of circumferential compression can effectively reduce the residual stresses of aluminum alloy ring parts.

In order to find out the uranium metallogenic potential of the Lower Cretaceous in Kelulun Sag of Hailar Basin, the spatial distribution of sequence stratigraphy, types and distribution characteristics of sedimentary facies and favorable spatial location of uranium enrichment in the area were studied by using sequence stratigraphy and sedimentary facies analysis methods based on core, logging and seismic data. The results show that the third-order and fourth-order sequence stratigraphic division marks of the target strata in the Kelulun Sag are determined. The target strata are divided into one super sequence, two three-order sequences and four fourth-order sequences, and the distribution characteristics of sequence stratigraphy are clarified. The sedimentary system of fan delta-lacustrine facies is mainly developed in the target layer in the area. The sedimentary facies plane has the characteristics of near source, fast phase change and small distribution range. The braided channel sand bodies of the fan delta plain and the underwater distributary channel sand bodies of the fan delta front have good uranium metallogenic potential.

The continental shale oil in the Da’anzhai section of the Ziliujing Formation in the Sichuan Basin has great exploration and development prospects. The sedimentary facies are diverse, the lithology is complex, and the vertical changes are fast. The understanding of the lithological differentiation combination mode and reservoir characteristics is unclear, which restricts the optimal selection of favorable shale oil reservoirs in the Da’anzhai section. Based on observations, thin section analysis, X-ray diffraction (XRD), vitrinite reflectance Ro testing, total organic carbon (TOC) content testing, physical property testing, rock pyrolysis, fluorescence analysis, and other experiments of four actual drilling cores in the central Sichuan Basin. By comprehensively analyzing mineral composition characteristics, as well as considering the content, occurrence, thickness of the shell layer, and its superimposed relationship with shale, seven lithological combination models for the Da’anzhai member in the central Sichuan basin were established (pure shale type, shale interbedded with floating shell limestone type, shale interbedded with millimeter scale shell limestone type, shale interbedded with centimeter scale shell limestone type, shale interbedded with centimeter scale shell limestone type, shale interbedded with shell limestone type, and pure shell limestone type). By integrating reservoir characteristic parameters such as TOC content, physical properties, oil content, and brittleness index, the reservoir characteristics of different lithological combinations were clarified. Based on the exploration and development practices of the Da’anzhai section and reservoir characteristics, a classification evaluation standard for reservoirs was established. It is believed that the lithological combination of shale interbedded with millimeter scale shell limestone and shale interbedded with centimeter scale shell limestone is the key layer for exploration and development, which has most favorable source reservoir combination, best physical properties, the highest oil saturation index(OSI) index, strong mobility, and good brittleness. The thick dark shale interval has the highest TOC content, good physical and oil properties, which is a potential interval for further exploration.

Schizophrenia is a persistent mental disorder manifested by significant abnormalities in perception, emotion, and behavior. Nevertheless, the neural mechanisms underlying this disorder are still not fully understood. In order to explore the differences in whole-brain causal connectivity between patients with schizophrenia and healthy controls in the resting state, a hierarchical degree (HD) index was proposed based on eigenmode method to overcome the inadequacy of node degree measured at a single level in traditional graph theory. It was found that the node degree of the whole-brain causal network of schizophrenia patients reduced. In addition, the most significant changes in in-degree were found in the motor system, whereas the most significant changes in out-degree were found in the default mode system. Higher-order node degree was further extracted and found to be superior to traditional graph theory degree in distinguishing schizophrenia patients from healthy controls based on a machine learning approach, and more accurately predicted positive and negative symptoms of schizophrenia, suggesting that higher-order network features can be used as biological indicators of schizophrenia. The findings of this paper reveal abnormal higher-order network features of schizophrenia and contribute to the advancement of objective diagnostic technologies for schizophrenia.

The study area is located in the Dongxiang Volcanic Basin in the middle part of the Qin-Hang mineralization belt, where several gold-lead-zinc (Au-Pb-Zn)-based mineralization and mineralization sites have been detected. Based on the principle of “from the known to the unknown”, combineing the results of physical and chemical exploration, such as the excitation middle gradient measurement and soil geochemistry, the characteristics of the combined parameters of the gamma spectra of Qiaoxi (HS-1) and Oujia (HS-2) was compared and analyzed, it was concluded that the anomaly centers of the characteristic parameters of the ground γ-ray were more concentrated than those of the anomalies obtained from soil geochemistry measurements. It was believed that the anomaly centers of the ground γ-ray energy spectral parameters were more concentrated than those of the soil geochemical measurements, and the F parameters were positively correlated with the anomalies in the K alteration zone, and the N parameters were positively correlated with the anomalies in the Na chemotaxis zone; and it was hypothesized that the HS-2 area has a relatively good prospect of gold polymetallic prospecting. The results provides a new theoretical basis for unit and super-unit delineation of volcanic areas, and proves that in practical work, the geological situation and characteristics of the area was comprehensively analyzed, and the appropriate combination of parameters was determine to indirectly explain the nature or cause of mineralized alteration in the area, which is more instructive than the traditional single-element spectral study.

In order to evaluate the development potential of coalbed methane in Yangjiapo block on the eastern margin of Ordos Basin and optimize the division method of its development geological units, the geological, resource, reservoir, hydrological and commingled production geological conditions of No.4+5 and No.8+9 coal seams in the block were described by reservoir fine description technology. By using the analogy method and multi-level fuzzy comprehensive evaluation method, the geological conditions of the Baode block in the north were compared, the difficulties of CBM development in the Yangjiapo block were analyzed and summarized, and the evaluation of CBM development potential and division method of development geological units were optimized. The results show that the resource conditions of a single coal seam in the Yangjiapo block are poor, and the cumulative resource abundance of the two coal seams is 1.08×10⁸ m³/km². The reservoir permeability is good, the difference in physical properties between the layers is small, and it has the potential for combined layer development. Faults have an important influence on the gas content and permeability of coal reservoirs within 300 m, and increase the risk of communicating with roof aquifers. The geological unit division method of coalbed methane development was applied to evaluate the development potential and commingled production compatibility of coalbed methane in the Yangjiapo Block. The six geological development units were divided into three levels of potential areas. It is pointed out that the middle part of Yangjiapo block is suitable for commingled development, some areas in the northwest are suitable for commingled development, and the northeast is suitable for replacement development.