standard substance

• 标准物质

standard substance的用法和样例：

例句

1. The two gaseous Reference Materials, Carbon dioxide in nitrogen and methane in air, belong to standard mixed gases.
   氮中二氧化碳和空气中甲烷气体标准物质属于标准混合气。
2. Their pureness deterimined in methods of two different priciples and conformed to the technical norm of first grade military standard substance.
   四种标准物质采用两种不同方法定值，结果均达到一级军用标准物质要求。