actinide element meaning in English

铜系元素
锕系元素

Nuclear criticality control of special actinide elements
专用锕系元素的核临界控制
Their discovery marks the first abundance determination of the actinides element thorium in a star beyond the milky way , and follows the detection of thorium in more than ten stars within the milky way
他们发现,标志着首丰测定的锕系元素钍星以外的银河系,跟检测钍十余恒星的银河系