A piezoelectric material, characterized in that a main component of the piezoelectric substance is PZT, which has perovskite type structure expressed in PbO3 of Zr and Ti in the formula), an element ratio Pb of Pb, Zr and Ti of the piezoelectric substance is 1. The peptides are at least 5 amino acids long and can be used in various specific assays for the detection of antibodies to HCV, for the detection of HCV antigens, or as immunogens. Each of a plurality of engine valves has its own respective drive cam, control cam, valve actuating link and valve pressing structure. A basic structure providing peripheral support for the leaflets includes two taller commissures on both sides of the larger leaflet, with a third, smaller commissure between the other two leaflets.