121 GB/T 14223-1993 内燃机活塞环 梯形环和楔形环 Internal combustion engines--Piston rings--Keystone rings and half keystone rings
122 GB/T 14415-1993 锅炉用水和冷却水分析方法 固体物质的测定 Analysis of water used in boiler and cooling system--Determination of solids matter
123 GB/T 14416-1993 锅炉蒸汽的采样方法 Methods for sampling boiler steem
124 GB/T 14417-1993 锅炉用水和冷却水分析方法 全硅的测定 Analysis of water used in boiler and cooling system--Determination of total silica