Xi Wang

Aiming at cleaning requirements of stainless-steel wall surface for nuclear plant station (NPS) fuel pool, an underwater cleaning robot with two motion modes of swimming and crawling was proposed. According to the structural symmetry characteristic, the mathematical hydrodynamic models for two motion modes were established respectively. The robot was simulated with a Fluent based mathematical model to test its movement of direct navigation, rotary motion in swimming mode and forward navigation in crawling mode. The coefficient corresponding to the mathematical hydrodynamic model was got from the simulation. The results show that the second order hydrodynamic coefficient is dominant. At the swimming mode, the resistance of downward motion is much larger than that of the upward motion. The lift force of sway direction is close to surge direction, while the resistance is much larger. Compared to the surge direction at swimming mode, the lift force is much larger at the crawling mode while the resistance is little changed. The research results provide important data basis for structural design and motion control of the cleaning robot.

Building upon incongruity theory, we cast paradox mindset as a novel explanatory mechanism and further propose subordinate interpersonal influence as a boundary condition to explain how and when le...

Deep-seated faults and folds of foreland basin systems have become important exploration targets in the recent years because they are crucial in controlling fluid migration and hydrocarbon accumulation. In this study, we analyzed the characteristics and formation history of these structures in the northwestern Sichuan Basin using recently acquired two-dimensional (2D) and three-dimensional (3D) seismic data. The seismic interpretation revealed that the thrust sheets, tectonic wedges, and foredeep were well developed in the northwestern Sichuan Basin from the mountain to the basin. Forward thrusts, fault-bend folds, and wedges are the main types of structures in the thrust sheets and tectonic wedges. The deep-seated faults and folds were easily recognized in the high-resolution 3D seismic data. The imbricate thrust faults that merged into detachment layers of the Lower Cambrian are the main types of structures in the foredeep, and they show a prominent strike-slip influence in the horizontal direction. The formation of these structures in the foredeep in the northwestern Sichuan Basin mainly endured two stages of thrusting, including those during the Middle-to-Late Triassic and Cenozoic. Based on the tectonic evolution and seismic data, we infer that these deep-seated faults and folds in the foredeep may have formed earlier than the northern Longmen Shan fold-and-thrust belts and they may have been initially active in the late of Early Triassic and reactive during the Cenozoic. Furthermore, evaporites in the Lower and Middle Triassic were crucial in forming these structures. The petroleum exploration data suggested that the deep-seated faults can facilitate hydrocarbon accumulation. The thrust faults in the foredeep were more likely to act as migration pathways for fluids instead of sealing barriers along the horizontal direction. The interconnected reservoirs of deep-seated folds possess a great potential to allow large-scale hydrocarbon accumulation. Our study provides a good example for evaluating the hydrocarbon exploration potential in the deeply buried area in the sedimentary basin.