news ieee c57.12.90 dielectric verification of retardant catalyst 1028 in superconducting magnet insulation layer ieee c57.12.90 dielectric verification of retardant catalyst 1028 in superconducting magnet insulat... 03/1970IEEE C57.12.90 Dielectric Verification of Retardant Catalyst 1028 in Superconducting Magnet Insulation Layer