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.

Bearing local fault occurs in the turboprop engine reduction gearbox, which affects engine running safely. Due to the complex structure and high speed of the reducer gearbox, the vibration signal used to monitor the operation state of the mechanical components is complicated. In order to detect the bearing local fault signal in time and extract fault feature accurately from the vibration signal, a method which was based on vibration signal combining FFT, fast kurtogram and envelope spectrum was proposed. Firstly, during the engine operation, the FFT(fast Fourier transform) spectrum was used to detect whether there was bearing fault component in the vibration signal; and then the fast kurtogram was applied to determine the frequency band distribution of the fault component; finally, the bearing fault characteristic frequency was acquired through envelope spectrum analysis. In the course of certain type of turboprop engine ground bench test, this method was used to accurately detect and diagnose the local spalling fault of the inner raceway. Therefore, this method can provide a basis for the engineering application on local fault detection and diagnosis of bearings in aero-engine reduction gearbox.

Considering the complex loading environment of the floating offshore wind turbine(FOWT), especially the fatigue damage risks brought by continuous and periodic wave actions, the fatigue performance of FOWT under wave coupling excitation was studied and a long-term fatigue damage assessment method for FOWT was proposed. Taking the Spar FOWT as an example, a nonlinear model under the wave coupling excitation of 8-DOF (dgree of freedom) was established based on the Lagrange equation, and the accuracy of the model was verified. Subsequently, on the basis of the established nonlinear model, the fatigue performance of the example FOWT was discussed according to the proposed method. The results indicate that the fatigue damage of FOWT is closely related to the wave load characteristics, and different damage performance is exhibited under different working conditions. Due to the randomness of sea conditions, only short-term fatigue estimation of the wind turbine is not enough to accurately understand its fatigue performance, and long-term fatigue analysis is needed. Moreover, the peak of short-term fatigue damage at the root of the wind turbine tower occurs near the tower's natural vibration period, while the peak of long-term fatigue damage occurs within the range of high probability sea state periods in the sea. Therefore, efforts should be made to avoid the natural vibration period of the FOWT coinciding with the peak period to prevent high-level damage accumulation and reduce fatigue damage. The analysis also demonstrates the effectiveness of the proposed Monte Carlo based long-term fatigue calculation method for FOWT, which not only has high accuracy but also less time consumption. The proposed improvement method can reduce output fluctuations, enhance stability, and provide more precise results.

The Shetianqiao Formation of the Devonian in central Hunan is an important shale gas reservoir in the Taihetang- Guanjiazui area. However, limited understanding of its geophysical and geochemical signatures has hindered the gas reservoir's large-scale exploration and exploitation. A research and development methodology was presented here based on sample analysis and geophysical characterization. Specifically, the method utilized quantification of shale gas occurrence characteristics and distribution patterns in the Shetianqiao Formation using sample analysis and the magnetotelluric (MT) geophysical data inversion technique. The results show that the overall resistivity of favorable layers in the Shetianqiao Formation is less than 200 Ω·m, with a thickness range of 600 to 900 meters and an average burial depth of 0~1 000 meters. Furthermore, the MT method reveals 15 faults and their associated multiplexing segments. It is also confirms that the organic matter in the Shetianqiao Formation is primarily II₂, with an organic carbon content ranging from 0.32% to 3.46% and an average at 0.80%. The average maturity R_o of the formation is 1.78%, indicating a high maturity stage.

To address the issue of composite scale in dense sandstone formations, an oil-in-acid microemulsion unblocking agent comprising acid, white oil, composite emulsifiers, and additives was developed. The internal structure and morphology of the microemulsion unblocking agent were characterized using transmission electron microscopy (TEM) and dynamic light scattering (DLS). Its performance was assessed in terms of thermal stability, dissolution efficiency for inorganic and organic scale plugs, and impact on reservoir permeability. The mechanism of unblocking was investigated using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The microemulsion unblocking agent exhibited a spherical dispersion in solution with an average particle size of 6 nm, and maintained stability at 90 ℃ for over 48 h. The dissolution rates for scale formed at different locations were 87.61% and 77.41%. The microemulsion unblocking agent the ability to transition from oil wettingto water wetting, and proved more efficient and faster in resolving complex scale plugging compared to traditional acid solvents. The microemulsion unblocking agent enhanced core permeability recovery rates to over 80%. Results highlight the advantages of the microemulsion unblocking agent, including excellent thermal stability, high scale dissolution capacity, and effective removal of both organic and inorganic composite scales, They can efficiently eliminate obstructions in the wellbore and near-wellbore regions, thereby clearing the wellbore and enhancing the flow paths in the formation and increasing oil and gas production capacity.

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.

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.

Hydrogen-injected into natural gas for pipeline transportation is an effective way to solve the high cost of hydrogen transportation. The rapid and uniform mixing of hydrogen and natural gas is an unavoidable problem to ensure the safety of hydrogen-blended natural gas pipeline transportation. Because the mixed gas flows back to the mixing pipe through the reflux pipe, it can continue to mix with the hydrogen-blended natural gas after entering, and improve the mixing uniformity. Therefore, a reflux mixer was used to mix hydrogen and natural gas. The effects of the inclination angle, diameter ratio and number of reflux pipes on the mixing properties of reflux mixers were analyzed by CFD. The results show that the reflux mixer has low pressure loss, high mixing uniformity and high reflux rate. When the inclination angle of reflux pipe, the diameter ratio of reflux pipe and the number of reflux pipe are 10°, 0.5 and 3, the reflux mixer achieves the best effect, and its pressure loss, mixing uniformity and the reflux rate are 76 Pa, 99.7% and 44.5%, respectively. The research results can provide reference for the parameters design and mixing performance of hydrogen-blended natural gas mixer.

In order to explore the deformation and failure mechanisms, as well as degradation characteristics of silt slopes under rainfall conditions, a large-scale slope model test apparatus was designed with silt slopes as the research subject. Multi-sensor internal monitoring and 3D laser scanning technology were applied. During slope instability under a rainfall intensity of 30 mm/h, data on moisture content, pore water pressure, soil pressure, and deformation and failure characteristics at various slope locations were collected. Results indicate that sensors at the slope toe have the fastest response, showing the highest rate of change. Rainwater accumulates at the slope toe, causing horizontal seepage, which leads to rapid increases in moisture content at the toe and lower middle sections of the slope, along with a reduction in soil shear strength. Under rainfall intensity conditions, the deformation and failure of silty slopes initiate at the slope toe, where small-scale collapses first occur. These progressively develop into transverse through-cracks, accompanied by minor-scale failures that extend upslope. Ultimately, these processes lead to overall slope failure. The findings offer theoretical insights to support engineering construction and protection in silty slope regions.

Aiming at the nonlinearity and multi-disturbance problems of the electric regulating valve control system in the actual production process, a control method based on the improved ant colony algorithm to optimize the single neuron PID (proportional integral derivative) was proposed and applied to the valve opening control. The self-learning and self-adaptive ability of the single-neuron network was used to achieve the online tuning of PID control parameters. The improved ant colony optimization algorithm was adopted to optimize the learning rate and neuron ratio coefficients in the single-neuron PID, which effectively overcomed the shortcomings of the single-neuron PID where the learning rate and neuron ratio coefficients could not achieve the expected control effect due to the empirical setting. The simulation comparison results show that, compared with the traditional PID, single neuron PID, and single neuron PID based on ant colony optimization algorithm optimization of the three control methods, the control method proposed overshoots the amount of reduction of 10.2%, 6.1%, and 1.8%, respectively. At the same time, the regulation time is correspondingly shortened by 0.22s, 0.07s, and 0.03s. It shows a stronger adaptive and anti-interference ability, which can make the valve opening control more stable and reliable.