Abstract: Provided are, an acidic gas removing agent with smaller variation in amounts of carbon dioxide absorption even in the coexistence of water in removing carbon dioxide in a gas; an acidic gas removing method; an absorption device provided with the acidic gas removing agent; and an acidic gas cleaning device. Used is an acidic gas removing agent comprising one or more selected from the group consisting of a hydroxy group-containing compound having a number-average molecular weight of 500 or more and a derivative of the hydroxy group-containing compound.

Abstract: An actuator includes a cylinder made of an aluminum alloy, a bottom part that closes one end of the cylinder, a cylindrical inner rod that is inserted in the cylinder to form an annular gap to the cylinder, a cylindrical piston rod that is closed at one end, slidably contacts with an outer periphery of the inner rod, and defines, together with the inner rod, an extension-side chamber, and a piston that is provided on the piston rod, slidably contacts with an inner periphery of the cylinder, and defines a compression-side chamber between the cylinder and the piston rod, in which the bottom part has a communication hole leading to the annular gap, and the cylinder has coating formed on the inner periphery by surface treatment using an electrolytic solution.

Abstract: A hydraulic device of the present invention includes an outer tube, a bottom portion that closes one end of the outer tube, an inner tube inserted into the outer tube, a movable portion movable relatively to the outer tube and the inner tube in an axial direction, coupling members attached to the outer periphery of the inner tube, and fixing tools that are in contact with the coupling members and fix the inner tube to the bottom portion.

Abstract: Preferences of each user are more accurately grasped from a playback history of a playback type content such as music and video and advertisement information that reflects preferences per user is served.