Abstract: According to one embodiment, an electronic device includes an elastic insulating base including a plurality of island-shaped portions and a plurality of strip-like portions each connecting respective adjacent pair of the plurality of island-shaped portions, electrical element located on each of the plurality of island-shaped portions and a plurality of wiring lines located in the plurality of strip-like portions respectively and each electrically connected to the electrical element. Each of the plurality of strip-like portions including a curved portion, and a ratio (R/W) of a radius (R) of curvature in the curved portions to the width W in the curved portion is in a range of 10?R/W?20.

Abstract: According to an aspect, a stretchable device includes: a resin base member; and a signal line and a strain gauge stacked on the resin base member. The resin base member includes: a plurality of bodies disposed separately from each other; and a plurality of hinges that couple the bodies while meandering. The hinges each include: a plurality of bends that bend and are disposed between the bodies; and a base that linearly extends to couple one of the bodies to a corresponding one of the bends. The signal line includes: a bend signal line stacked on the bends; and a base signal line stacked on the base. The base signal line has an occupied area per unit length in a length direction of the signal line larger than the bend signal line when viewed in a stacking direction in which the signal line is stacked on the resin base member.

Abstract: A method for one-side root path welding of a pipe joint comprises the steps of forming a ring groove having a V-shaped bottom portion thereof at end faces of both pipes whose joint is circumferentially welded, attaching a backing material to a butt portion of the pipes from an internal side of the pipes, running an automatic welding machine along a guide rail mounted on an outer surface of the pipes in the circumferential direction thereof, controlling a position of a welding torch along a seam by means of an arc sensor, and welding root pass from the outer side of the pipes with a predetermined welding current and at a welding speed in a high-speed rotating arc welding of the pipes at a predetermined rotational speed and with a predetermined diameter of rotation. The rotational speed of arc is from 10 to 150 Hz. The rotation diameter of the arc is from 1 to 4 mm. The welding current is from 200 to 500 A. The welding speed is from 75 to 300 cm/min.