Helium may best be known as the lighter-than-air gas used to fill party balloons, but it's also key to medical applications like MRI scans and for nuclear power.
원문출처 : http://www.cnn.com/2016/06/28/africa/helium-discovery-tanzania/index.html
원문출처 : http://www.cnn.com/2016/06/28/africa/helium-discovery-tanzania/index.html