Abstract: In a fitting process, a first pipe made of metal and a second pipe made of metal are fitted together such that an outer wall of the first pipe and an inner wall of the second pipe are opposed to each other. In a preheating process, the pipes are heated such that temperature of a fitting surface converges at a first temperature, which is lower than melting points of the pipes. In a welding process, the second pipe is irradiated with a laser to heat the pipes such that the temperature of the fitting surface converges at a second temperature, which is equal to or higher than the melting points; a vicinity of the fitting surface is melted to produce a weld penetration part; and the pipes are joined together to form a pipe joint product. An output and irradiation time of the laser in the welding process are set, so that the second temperature becomes such a temperature that a leading end of the penetration part is located within thickness of the first pipe.

Abstract: According to a laser welding method, an inert gas injection process and welding process are performed. In the inert gas injection process, inert gas is injected into an inside of a first metal pipe; and air inside the first pipe is discharged into the outside. In the welding process, a second metal pipe is irradiated with a laser from radially outward of the second pipe; metal is melted with a penetration depth of a penetration part adjusted such that a leading end of the penetration part is located within thickness of the first pipe; and the first and second pipes are welded together along the circumferential direction to form a pipe joint product. An inner wall of the first pipe maintains its pre-welding metallic luster. An injector includes an injection nozzle, a fuel passage member, a valve member accommodated in the fuel passage member, and a driving unit driving the valve member.

Abstract: A method for manufacturing a non-linear resistive element array on a substrate, comprising: depositing a first conductive layer on the substrate and selectively forming the layer in a desired pattern; depositing a non-linear resistive layer on the first conductive layer; depositing a second conductive layer on the non-linear resistive layer; forming the second conductive layer in a desired pattern by etching process using a patterned resist layer as a mask; and forming the non-linear resistive layer in a desired pattern using the resist layer as a mask.

Abstract: An electro-optical device has a plurality of electro-optical elements arranged in a matrix and optically activated selectively in response to voltage pulses applied thereto. Each electro-optical element is comprised of first and second electrode layers opposed to each other for selectively receiving thereacross a voltage pulse, and a third electrode layer adjacent to the first electrode layer and in opposed relation to the second electrode layer. A liquid crystal layer is interposed between the second and third electrode layers and optically activated when electrically charged through the third electrode layer. A non-linear-resistive layer is disposed between the first and third electrode layers and operative when the voltage pulse is applied across the first and second electrode layers to increase its electro-conductivity for electrically connecting the first electrode layer to the third electrode layer to thereby electrically charge the liquid crystal layer in response to the voltage pulse.

Abstract: A matrix electro-optical device is comprised of a plurality of picture elements arranged in a row-and-column matrix. A plurality of switching elements are formed on a substrate of the device and are series-connected to the respective picture elements to selectively drive the picture elements. The switching element is comprised of a non-linear-resistive layer composed of non-stoichiometric silicon nitride or silicon oxide and interposed between a pair of electro-conductive layers.