Abstract: A dielectric resonator device comprising a resonator body having a dielectric resonator element, a supporting member and a mounting flange which are integrally formed and are made of the same dielectric ceramic material, the mounting flange having an effective heat dissipating function and being removably fixed on a base member.

Abstract: A process for preparing a substrate for optical recording media which comprises injection-molding a polyvinylacetal resin resulting from acetalization of polyvinylalcohol to a degree of at least 60 mole % with at least one acetalizing agent selected from the group consisting of aliphatic aldehydes, alicyclic aldehydes, aromatic aldehydes and heterocyclic aldehydes.

Abstract: A dielectric ceramic composition is disclosed, comprising as three components lead nickel niobate, lead titanate, and lead magnesium iron tungstate, wherein the composition in terms of the three components is represented by the formulaX[Pb(Ni.sub.1/3 Nb.sub.2/3)O.sub.3 ].Y[PbTiO.sub.3 ].Z[Pb(Mg.sub.1/4 Fe.sub.1/4 W.sub.1/2)O.sub.3 ]wherein X+Y+Z=1.00, X, Y, and Z are within the polyhedral area formed by lines connecting points a (X=0.78, Y=0.20, Z=0.02), b (X=0.50, Y=0.20, Z=0.30), c (X=0.40, Y=0.30, Z=0.30), d (X=0.50, Y=0.40, Z=0.10), and e (X=0.58, Y=0.40, Z=0.02) of an X-Y-Z ternary phase diagram. The composition can be sintered at a relatively low temperature, has a high dielectric constant, and is useful as a material for condensers and electrostriction elements.