Abstract: A power screwdriver (10) includes a bit holder (14) bored to receive the shaft of a screwdriver bit (12) and adapted to securely hold the screwdriver bit (12) in place, and a housing (18) having a through cavity (16). The bit holder (14) is inserted into the through cavity (16) so that the bit holder (14) is rotatable about and movable along the axis of the bit holder. This arrangement securely holds the screwdriver bit and thus, minimize rattling of the screwdriver bit during rotation.

Abstract: Disclosed is a film comprising PMMA and a fluorescent substance having a xanthene skeleton and a lactone ring and/or a fluorescent substance having a xanthene skeleton and a group —COOR, where R represents a hydrogen atom or a substituent, capable of forming an intramolecular lactone ring, said fluorescent substances being dispersed in the PMMA. The film is useful as an optical memory.

Abstract: A power screwdriver (10) includes a bit holder (14) bored to receive the shaft of a screwdriver bit (12) and adapted to securely hold the screwdriver bit (12) in place, and a housing (18) having a through cavity (16). The bit holder (14) is inserted into the through cavity (16) so that the bit holder (14) is rotatable about and movable along the axis of the bit holder. This arrangement securely holds the screwdriver bit and thus, minimize rattling of the screwdriver bit during rotation.

Abstract: Disclosed is a film comprising PMMA and a fluorescent substance having a xanthene skeleton and a lactone ring and/or a fluorescent substance having a xanthene skeleton and a group —COOR, where R represents a hydrogen atom or a substituent, capable of forming an intramolecular lactone ring, said fluorescent substances being dispersed in the PMMA. The film is useful as an optical memory.

Abstract: A semiconductor device structure using an SOI substrate is provided along with a method of manufacturing the structure, and the structure makes it possible to reduce parasitic capacitance while preventing the parasitic bipolar effect caused by the floating substrate effect and preventing supporting substrate bias from changing the threshold voltage. The semiconductor device using an SOI substrate is characterized in that a P-well diffusion layer or an N-well diffusion layer is formed only in a body region located below a gate electrode in a semiconductor thin film.