six product oils are analyzed by gas chromatography.They are identified by means of the comparison of the fingerprints of normal alkane in them,the analyses of the relative concentration distributions of normal alkane in them,the character ratios of them,and the fuzzy cluster analysis of their fingerprint information.It is shown that,when there is greater difference in composition of the product oils,fingerprint comparison is a visual,fast and effective identification method;but when the difference is less,...