Abstract: Disclosed is a black powder comprising silica particles that contain carbon. Each of the silica particles is single-layered. The content of carbon contained in the surfaces of the silica particles measured by an X-ray photoelectron spectroscopy is 1% by mass or less.

Abstract: Disclosed is a black powder comprising silica particles that contain carbon. Each of the silica particles is single-layered. The content of carbon contained in the surfaces of the silica particles measured by an X-ray photoelectron spectroscopy is 1% by mass or less.

Abstract: A rotor includes a rotating shaft, a core and a Halbach array magnet. The Halbach array magnet has first magnet portions each having its magnetization direction oriented along a radial direction and second magnet portions each having its magnetization direction oriented along a circumferential direction. The first magnet portions and the second magnet portions are alternately arranged in the circumferential direction. The core has a shaft-fixed portion, a yoke portion and a plurality of connection portions. The connection portions are arranged in the circumferential direction with gaps formed therebetween. On an inner circumferential surface of the yoke portion, there are formed additional-function portions to extend radially inward from the inner circumferential surface of the yoke portion. Each of the additional-function portions is located radially inside a corresponding one of the second magnet portions and has an additional function in addition to a function of forming the magnetic path.

Abstract: Disclosed is a black powder comprising silica particles that contain carbon. Each of the silica particles is single-layered. The content of carbon contained in the surfaces of the silica particles measured by an X-ray photoelectron spectroscopy is 1% by mass or less.

Abstract: A medical hollow needle assembly includes an outer cylindrical body including a through-hole; a hollow needle having an outer peripheral surface, wherein a proximal portion of the hollow needle is disposed in the through-hole of the outer cylindrical body, and wherein the outer peripheral surface of the hollow needle has an outer reduced-diameter surface that has a smaller outer diameter than that of a more proximal portion of the outer peripheral surface of the hollow needle; and an inner cylindrical body including an insertion hole in which the hollow needle is disposed, wherein the inner cylindrical body is disposed between the hollow needle and an inner peripheral surface of the through-hole of the outer cylindrical body, and wherein the inner cylindrical body joins the outer cylindrical body and the hollow needle.

Abstract: A medical hollow needle assembly includes an outer cylindrical body including a through-hole; a hollow needle having an outer peripheral surface, wherein a proximal portion of the hollow needle is disposed in the through-hole of the outer cylindrical body, and wherein the outer peripheral surface of the hollow needle has an outer reduced-diameter surface that has a smaller outer diameter than that of a more proximal portion of the outer peripheral surface of the hollow needle; and an inner cylindrical body including an insertion hole in which the hollow needle is disposed, wherein the inner cylindrical body is disposed between the hollow needle and an inner peripheral surface of the through-hole of the outer cylindrical body, and wherein the inner cylindrical body joins the outer cylindrical body and the hollow needle.