Abstract: The present invention relates to an air foil journal bearing including a bump foil having a plurality of elastic bumps and provided and coupled inside a bearing housing, a mid-foil provided inside the bump foil, formed in a circumferential direction, and having at least one circumferential end coupled to the bearing housing, and a top foil provided inside the mid-foil, formed in the circumferential direction, and having at least one circumferential end coupled to the bearing housing, in which a stepped portion is formed as a radius of an inner peripheral surface of a partial circumferential region of the mid-foil is smaller than a radius of an inner peripheral surface of the remaining region, such that an additional pressure is generated in a section in which a maximum positive pressure is applied when a rotor rotates at low speed, such that the rotor may float at a relatively low rotational speed, and friction and vibration between the rotor and the top foil may be reduced.

Abstract: The present disclosure relates to a cell culture composition including a Chlorella extract. According to the cell culture medium composition including the Chlorella extract according to an aspect, the medium including the Chlorella extract can improve the cell proliferation ability of bovine myogenic stem cells. Thus, the Chlorella extract can be used as a substitute for fetal bovine serum.