日韩精品内射视频免费观看_亚洲av精品久久久蜜臀搜查官_艳妇扶着巨龙缓缓坐下小说_外企少妇黑人满足在线观看_瀬名 无码番号_美国老妇日韩欧美老妇日韩AV_午夜在线不卡免费人成毛片_vicineko史莱姆大战链接_影音先锋aⅴ资源网站_av无码人妖系列综合网

The Japanese call rare earths as “the seeds of technology.” The US Department of Energy calls them “technology metals.” They make possible the high tech world we live in today everything from the miniaturization of electronics, to the enabling of green energy and medical technologies, to supporting a myriad of essential telecommunications and defense systems. They are the elements that have become irreplaceable to our world of technology owing to their unique magnetic, phosphorescent, and catalytic properties.

Rare earth elements are a set of seventeen chemical elements in the periodic table, specifically the fifteen lanthanides plus scandium and yttrium. Scandium and yttrium are considered rare earth elements since they tend to occur in the same ore deposits as the lanthanides and exhibit similar chemical properties. While named rare earths, they are in fact not that rare and are relatively abundant in the Earth's crust. What is unusual is to find them in quantities significant enough to support economic mineral development.