Abstract: Provided are a technique with which a satin-like appearance can be obtained in nickel-plating by a nickel-plating additive characterized by containing a benzethonium salt, a satin nickel-plating bath containing the same, and a satin nickel-plating method using the same.

Abstract: Provided are a technique with which a satin-like appearance can be obtained in nickel-plating by a nickel-plating additive characterized by containing a benzethonium salt, a satin nickel-plating bath containing the same, and a satin nickel-plating method using the same.

Abstract: A method of producing polyurethane foam slab by allowing a urethane foam stock solution in a tank to expand in a reduced pressure. The flatness of the top of the polyurethane foam is secured by providing a lifting jig or a plate within the tank, or by rotating the tank. An apparatus for carrying out the method is also provided.

Abstract: A pulse data signal and a DC power signal are transmitted over a pair of transmission lines interconnecting a main operating unit and telephone sets in a key telephone system. The main operating unit and each telephone set includes a pulse transmitting and receiving circuit and a transformer having a core and first and second pairs of opposed windings. The individual windings in the first winding pair are connected to input and output terminals, respectively, of the pulse transmitting and receiving circuit. One terminal of each individual winding in the second winding pair is connected to a transmission line. A DC power source is connected across the other winding terminals in the second winding pair in the main operating unit. In the telephone set, the other winding terminals in the second winding pair are connected with a power supply circuit which provides power to various component circuits in the telephone set.