liquid helium液氦;液态氦
helium gas氦气
1.Firstly, all existing supplies of helium ought to be conserved and released only by permit, with medical uses receiving precedence over other commercial or recreational demands.
首先,所有现有的氦供应应该被保存下来,并且只有在获得许可的情况下才能释放,医疗用途应优先于其他商业或娱乐需求。
2.Helium is the by product of millennia of radioactive decay from the elements thorium and uranium.
氦是钍和铀元素数千年放射性衰变的副产品。