Abstract: The disclosure provides a bolt including a main body, a head portion and a thread portion. The main body has a central axis. The head portion connects the main body. The thread portion is connected to the main body and runs around the central axis. The thread portion has a bearing surface facing toward the head portion. The bearing surface is a continuous curved surface or has an inflection point. The bearing surface includes a concave curved surface, a convex curved surface and a flank surface. The concave curved surface connects the main body. The convex curved surface is located further away from the main body than the concave curved surface. One side of the convex curved surface connects the concave curved surface, and another side of the convex curved surface connects the flank surface.

Abstract: The disclosure provides a bolt including a main body, a head portion and a thread portion. The main body has a central axis. The head portion connects the main body. The thread portion is connected to the main body and runs around the central axis. The thread portion has a bearing surface facing toward the head portion. The bearing surface is a continuous curved surface or has an inflection point. The bearing surface includes a concave curved surface, a convex curved surface and a flank surface. The concave curved surface connects the main body. The convex curved surface is located further away from the main body than the concave curved surface. One side of the convex curved surface connects the concave curved surface, and another side of the convex curved surface connects the flank surface.

Abstract: The present invention relates to bicomponent conjugate fibers having excellent crimping property, comprising: (A) a thermoplastic polyester elastomer (TPEE) as a first component, and (B) a polyester polymer as a second component. The present invention also relates to yarns and fabrics comprising said bicomponent conjugate fibers.

Abstract: A tracking method executed by an optical disc device. The optical disc device includes an optical head for emitting light to read or write data from or to an optical disc. The tracking method includes steps of: providing a table for listing a plurality of predetermined track classes, and a plurality of tracking errors; calculating the number of tracks between a current track in which the optical head is currently positioned and a target track from or to which the optical head reads or writes data; determining whether the number of tracks reaches a predetermined number; searching the table for the corresponding tracking errors when the number of tracking error reaches a predetermined number; calculating second jumping tracks based on the first jumping tracks and the found tracking errors; and driving the optical head to move to the second jumping tracks for tracking.