Abstract: A keyboard unit includes a plurality of keytops; a baseplate supporting the plurality of keytops; and a light-emitting module having a light guide plate, a first flexible sheet covering a first surface of the light guide plate, and a second flexible sheet covering a second surface of the light guide plate opposite to the first surface of the light guide plate, wherein the light-emitting module is disposed on the baseplate such that the first flexible sheet is between the baseplate and the light guide plate, a hole is formed in the light-emitting module through the light guide plate, the first flexible sheet, and the second flexible sheet, and at a periphery of the hole, the second flexible sheet is fixed to the baseplate to form a continuous barrier from the second surface of the light guide plate to the baseplate.

Abstract: The present invention relates to a hollow drilling steel rod including a stem portion and a thread portion positioned at an end portion in an axial direction with respect to the stem portion, the hollow drilling steel rod being constituted of a steel having a specific composition described in the present specification, in which the thread portion includes a thread having been subjected to a high frequency quenching, and the thread portion and the stem portion separate from each other have been joined by a friction welding.

Abstract: The present invention relates to a hollow drilling steel rod including a stem portion and a thread portion positioned at an end portion in an axial direction with respect to the stem portion, the hollow drilling steel rod being constituted of a steel having a specific composition described in the present specification, in which the thread portion includes a thread having been subjected to a high frequency quenching, and the thread portion and the stem portion separate from each other have been joined by a friction welding.

Abstract: There is provided a membrane material for a gas holder having abrasion resistance and flex resistance usable as a gas holder, in addition to strength of a base fabric, and having high gas barrier properties. A membrane material for a gas holder, which is used in a gas holder for storing or recovering gas, includes at least 4 layers of a protective layer, a base fabric layer, a gas barrier layer and a protective layer laminated in this order.

Abstract: There is provided a membrane material for a gas folder having abrasion resistance and flex resistance usable as a gas holder, in addition to strength of a base fabric, and having high gas barrier properties. A membrane material for a gas holder, which is used in a gas holder for storing or recovering gas, comprising at least 4 layers of a protective layer, a base fabric layer, a gas barrier layer and a protective layer laminated in this order.