Abstract:
A method of obtaining high-purity 7-aminocephalosporanic acid from an aqueous solution thereof contaminated with alpha -aminoadipic acid, which comprises treating the aqueous solution with a strongly basic styrene-base anion-exchange resin to thereby remove the alpha -aminoadipic acid.
Abstract:
An apparatus for detecting abnormal air-fuel ratio variation among cylinders of a multi-cylinder internal combustion engine (1) according to the invention includes: a catalyst element (11) that oxidizes hydrogen contained in exhaust gas to remove the hydrogen; a first air-fuel ratio sensor (17) that detects an air-fuel ratio of exhaust gas that has not passed through the catalyst element (11); a second air-fuel ratio sensor (18) that detects an air-fuel ratio of exhaust gas that has passed through the catalyst element (11); and a unit (20) that determines whether abnormal air-fuel ratio variation among the cylinders has occurred based on an amount by which a value detected by the second air-fuel ratio sensor (18) is leaner than a value detected by the first air-fuel ratio sensor (17).
Abstract:
An apparatus for detecting abnormal air-fuel ratio variation among cylinders of a multi-cylinder internal combustion engine (1) according to the invention includes: a catalyst element (11) that oxidizes hydrogen contained in exhaust gas to remove the hydrogen; a first air-fuel ratio sensor (17) that detects an air-fuel ratio of exhaust gas that has not passed through the catalyst element (11); a second air-fuel ratio sensor (18) that detects an air-fuel ratio of exhaust gas that has passed through the catalyst element (11); and a unit (20) that determines whether abnormal air-fuel ratio variation among the cylinders has occurred based on an amount by which a value detected by the second air-fuel ratio sensor (18) is leaner than a value detected by the first air-fuel ratio sensor (17).