Abstract: The invention relates to a gas bearing for contactlessly bearing a rotatable element (50). The gas bearing comprises: a housing (100) having an opening for receiving the rotatable element; and at least two sliding films (200), which are arranged on an interior (110) of the opening without overlap and which each have a first end portion (210) and a second end portion (220) for support on the housing (100). The sliding films (200) are designed to radially support the rotatable element relative to the housing (100) only by means of the first and second end portions (210, 220), the second end portion (220) providing frictional contact with the interior (110) and the first end portion (210) being fastened to the housing.

Abstract: The invention relates to a gas bearing for contactlessly bearing a rotatable element (50). The gas bearing comprises: a housing (100) having an opening for receiving the rotatable element; and at least two sliding films (200), which are arranged on an interior (110) of the opening without overlap and which each have a first end portion (210) and a second end portion (220) for support on the housing (100). The sliding films (200) are designed to radially support the rotatable element relative to the housing (100) only by means of the first and second end portions (210, 220), the second end portion (220) providing frictional contact with the interior (110) and the first end portion (210) being fastened to the housing.

Abstract: Wave-like concaves/convexes are formed on respective flat surfaces of a heat exchange tube, such that crest lines of continuing V shapes in a horizontal direction and trough lines of continuing V shapes in the horizontal direction are alternately arranged and that bends of the V shapes form curve lines. This configuration reduces the stress concentration at the bends in a press-forming process, compared with a configuration that crest lines and trough lines have bends formed in a shape of continuing sharply-angled V shapes in the horizontal direction. As a result, this configuration increases the yield in the press-forming process at a fixed amplitude of the wave-like concaves/convexes and increases the amplitude of the wave-like concaves/convexes at a fixed yield in the press-forming process.