Abstract: The present invention relates to a positive electrode active material for non-aqueous electrolyte secondary battery, including lithium-nickel composite oxide particles having a layer structure of hexagonal system; and a lithium tungstate coating film disposed on a surface of secondary particles of the lithium-nickel composite oxide particles, wherein the positive electrode active material for non-aqueous electrolyte secondary battery includes, as metallic elements, lithium (Li), nickel (Ni), cobalt (Co), element M (M) which is at least one element selected from Mn, V, Mg, Mo, Nb, Ti, Ca, Cr, Zr, Ta, and Al, and tungsten (W), wherein a ratio of amount of substance in the metallic elements contained is Li:Ni:Co:M:W=a:1-x-y:x:y:z, wherein 0.97?a?1.25, 0?x?0.35, 0?y?0.35, and 0.005?z?0.030.

Abstract: A door device includes a door slidable between a first position and a second position; an air cylinder having a first air chamber to which air is supplied to apply a first assist force to the door in a first direction from the first position toward the second position; a fluid passage connecting the first air chamber and an air supply source; a switch valve provided at the fluid passage; and a manipulation switch to switch the switch valve between a first state and a second state. The door, in the first state, is movable in the first direction and a second direction opposite to the first direction without the first assist force. The first assist force is applied to the door in the second state. The door at the first position closes an opening a machine tool. The door at the second position fully opens the opening.