Abstract: A ceramic composition which forms, when sintered, a dielectric having a crystal structure represented by the general formula:[Pb.sub.1-x A.sub.x ].sub.[A] (B.sub.1,B.sub.2).sub.[B] O.sub.3where A is at least one element selected from the group consisting of Ca, Sr, Ba, Ag, La and Nd, B.sub.1 is at least one element selected from the group consisting of Mg, Zn, Ni, Co, Fe, Mn and In, B.sub.2 is at least one element selected from the group consisting of Nb, W, Ta and Sb, x is 0 to 0.5, and the molar ratio of [A]/[B] is 0.995 or more, but 0.99 or less.

Abstract: A gas turbine engine in which the air compressed by a compressor provided therein is injected into a combustion chamber provided therein through an air injection valve after passing through a first air passageway formed integrally with the main housing and a second air passageway formed integrally with the combustion chamber housing. One end of the first air passageway is formed into a funnel shape, so that the air compressed by the compressor can efficiently enter the first air passageway. Since the air flowing through the air passageway according to the present invention is heated while passing along the combustion chamber, it is possible to enhance the combustion efficiency.