镧系元素

例句：

1. 1. The lanthanide series is a group of elements that have similar chemical properties.
   镧系元素是一组具有相似化学性质的元素。
2. 2. Lanthanides are used in various applications, such as cathode materials for fluorescent lamps.
   镧系元素在各种应用中被使用，如用于荧光灯的阴极材料。
3. 3. The discovery of new lanthanide compounds has led to breakthroughs in medical imaging technologies.
   发现新的镧系化合物已经导致了医学成像技术的重大突破。