A compound represented by formula :r-; X2 represents a methylene group, O, \u2014NR3\u2014, or \u2014Sr-; Q\u2032 represents a heteroaryl group, a heteroarylalkyl group, a substituted aryl group, or an aralkyl group; Cycle moiety represents an aryl ring or a heteroaryl ring; and the wavy line represents an E-isomer or a Z-isomer), a salt of the compound, or a solvate of the compound or the salt. An inverter is connected to the output of a turbine generator. The sponge is sterilized by electron beam radiation to destroy micro organisms that can cause contamination of the final product.