知识贝壳
知识贝壳
所属栏目：英汉双解化学
A soft silvery -white radioac-tive metallic element that is the first mem-ber of the actinoid series. It occurs in mi-nute quantities in uranium ores and themetal can be obtained by reducing the trif-luoride with lithium. It can be produced byneutron bomb ......（本文共 639 字 ） [阅读本文] >>