Abstract: An array substrate, a preparing method thereof, a display panel and a display apparatus are disclosed. The array substrate includes: a base substrate (1); a driving circuit structure (2) on the base substrate (1); a planarization layer (3) and a plurality of electrode structures (4) successively located on a side, facing away from the base substrate (1), of the driving circuit structure (2); insulation structures (5) in gap areas between adjacent electrode structures (4); and pixel defining structures (6) on a side, facing away from the base substrate (1), of the insulation structures (5). The thickness of the insulation structures (5) is not smaller than the thickness of the electrode structures (4). An orthographic projection of the pixel defining structures (6) on the base substrate (1) at least completely covers the insulation structures (5).

Abstract: The invention relates to a downhole-started self-locking casing centralizer, comprising a connecting part (1) and a connecting part (2) on both ends, a central supporting part being arranged between the connecting part (1) and the connecting part (2), and characterized in that the central supporting part comprises a hollow coupler, and at least three N-stage piston self-locking support devices extending by stages under pressure are evenly distributed along the circumference of the coupler, N?2. The invention has the following advantages: 1. a threaded integral structure is adopted; 2. a downhole-started self-locking support structure is adopted; and 3. a circular arc support cap helps ensure large support force and reduce damage to borehole walls.

Abstract: The present invention relates to a wind turbine maintenance system and a method of maintenance therein. A wind turbine maintenance system is provided, for carrying out a maintenance task in a nacelle of a wind turbine, comprising a maintenance robot, further comprising a detection unit, for identifying a fault in a sub-system in the nacelle and generating fault information, a processor unit, adapted to receive fault information from the detection unit and control the maintenance robot to perform a maintenance task, a manipulation arm to perform the maintenance task on the identified sub-system. In another aspect, a method of carrying out a maintenance task in a wind turbine is provided.