Abstract: The stator vane is provided with a leading edge which is cut into a different depth in dependence on a span-wise position so that a blade inlet angle may vary along a span-wise direction according to a prescribed pattern. By thus optimizing the depth of the cut along the leading edge of the stator vane, the leading edge blade inlet angle can be optimized along the entire length of the stator vane even if the stator vane consists of a two-dimensional aerofoil, and the vane is provided with a substantially conformal cross section in parts which are not affected by the cut in the leading edge. Thereby, the efficiency of the turbine can be optimized while minimizing the cost.

Abstract: The stator vane of the present invention is provided with a leading edge which is cut into a different depth in dependence on a span-wise position so that a blade inlet angle may vary along a span-wise direction according to a prescribed pattern. By thus optimizing the depth of the cut along the leading edge of the stator vane, the leading edge blade inlet angle can be optimized along the entire length of the stator vane even if the stator vane consists of a two-dimensional aerofoil, and the vane is provided with a substantially conformal cross section in parts which are not affected by the cut in the leading edge. Thereby, the efficiency of the turbine can be optimized while minimizing the cost.

Abstract: A method of producing a prepolymer of aromatic polythiazole from an aromatic diaminodithiol compound or a salt thereof and a dicarboxylic acid derivative, the prepolymer having a repeating unit represented by the following general formula: ##STR1## wherein R.sub.1 is an aromatic group having at least one benzene nucleus, and R.sub.2 is a residual group of the dicarboxylic acid derivative, comprising the step of polymerizing the aromatic diaminodithiol compound or a salt thereof and the dicarboxylic acid derivative by an interfacial polymerization method.

Abstract: A method of producing a prepolymer of aromatic polythiazole from an aromatic diaminodithiol compound salt and a dicarboxylic acid derivative, comprising the step of polymerizing the aromatic diaminodithiol compound salt and the dicarboxylic acid derivative in the presence of a phosphoric acid compound at a temperature of 70.degree.-140.degree. C.