Abstract: A ceramic trimmer capacitor comprising a cylindrical casing, a stator and a rotor comprising a rotor casing and a dielectric assembly consisting of a disk-shaped ceramic dielectric member, a semicircular dielectric layer formed upon the upper surface of the dielectric member and having a low dielectric constant less than 20 and a coefficient of thermal expansion substantially equal to the dielectric member and a rotor electrode formed on the whole surface of the dielectric member including the semicircular dielectric layer, the dielectric assembly being inserted into the rotor casing and electrically and mechanically connected thereto; the stator and the rotor being placed in the cylindrical casing and resiliently supported. Stray capacitance is almost negligible; the variable capacitance range may be considerably improved; and the mechanical strength may be increased. The ceramic trimmer capacitor is especially adapted to be used in an electronic watch.

Abstract: In a boiler having a plurality of heat exchanger stages such as a superheater, an evaporator and a preheater, disposed in a combustion gas channel between heat exchangers including an optimum catalytic reaction temperature region are a denitration catalyst layer crossing said channel and a reductant feeding device for adding a reductant such as ammonia gas at a point a little short of catalyst layer. The denitration catalyst layer comprises a number of plate-like catalyst bodies whose plate surfaces extend along the direction of flow of gas, and desirably it is honey-comb-shaped. If the boiler is a waste heat boiler, the denitration catalyst layer will be disposed between the superheater and the evaporator.