Abstract: The invention provides a coil comprising a plurality of stacked coil elements connected together at conductor ends to form at least one series of spiral conductors, the coil being characterized in that each of the coil elements includes a sheet insulator, a first conductor in a planar spiral form and provided on one surface of the insulator and a second conductor in a planar spiral form and provided on the other surface of the insulator, the conductors on the respective surfaces of the insulator being wound spirally in directions opposite to each other when seen from above at the same side of the insulator.

Abstract: This invention provides a copper or copper alloy mold for continuous casting of steel characterized in that a nickel-boron alloy plating layer containing 0.06 to 0.3 wt. % of boron is formed on its interior surface.

Abstract: The invention provides a printed wiring board having a plurality of copper foil cores superposed over one another and spaced away from one another. The portions of the cores are exposed at the end surfaces of the board. A plurality of holes extend vertically through the copper foil cores and have hole-defining internal surfaces so plated as to connect the cores to one another. Another printed wiring board has a plurality of copper foil cores superposed over one another and spaced away from one another. The end portions of the cores are exposed at the end surfaces of the board. A plurality of holes extend vertically through the copper foil cores and have hole-defining internal surfaces so plated as to connect the cores to one another. The underside of the copper foil core at the lowermost position is exposed at a recess formed on the rear side of the board. Plating is formed which extends from the lowermost copper foil core to the rear side of the board.

Abstract: A screen printing apparatus and method for forming printed wiring on a board. The apparatus comprises a holder for holding the board upright in posiiton, and a printing device arranged vertically for at least one surface of the board as held in position by the holder, the printing device including a spatula-like squeegee, a screen, a first scraper in the form of a spatula for scraping ink from the front surface of the screen remote from the board and a second scraper in the form of a spatula for scraping ink from the rear surface of the screen adjacent the board, the first scraper and the second scraper being mechanically drivable at the same time to scrape the screen with the first scraper positioned below or above or at the same level as the second scraper, the squeegee being mechanically drivable for squeegeeing ink on the front surface of the screen after the first and second scrapers scrape the screen.

Abstract: This invention provides a method of continuously casting steel with the use of a copper or copper alloy mold comprising a pair of long side mold pieces and a pair of short side mold pieces slidable along the long side mold pieces for changing the width of the slab to be produced, the method being characterized by inserting into the mold at each corner thereof a cooling member made of a material identical or substantially identical with the steel to be cast and slidingly moving the short side mold pieces under reduced clamping pressure acting between the long side mold pieces and the short side mold pieces in contact therewith.

Abstract: A mold of copper or copper alloy for continuously casting steel comprises a rough inner surface, a plating of nickel, cobalt or alloy thereof formed over the inner surface and a chromium plating formed over said plating. The mold has a prolonged mold life, gives steel slabs with improved qualities and reduces amounts of lubricating material used in the molding operation.

Abstract: This invention provides a process for producing a printed circuit board characterized by the steps of drilling holes in a copper clad laminate, treating the entire surface of the laminate including the hole-defining inner surfaces with a catalyst, removing the catalyst from the surface of the copper foil of the laminate by mechanically cleaning the surface of the copper foil, depositing electroless nickel only on the hole-defining inner surfaces, forming a pattern with an etching resist, etching away the copper foil except at the pattern area, removing the etching resist, masking with a solder resist the entire surface except at the hole-defining inner surfaces and the lands, and subjecting the hole-defining inner surfaces and the lands to electroless copper plating.