单词	protactinium
释义	protactinium noun prot·​ac·​tin·​i·​um ˌprō-ˌtak-ˈti-nē-əm  : a shiny radioactive metallic element of relatively short life see Chemical Elements Table Example Sentences Recent Examples on the Web These natural uranium isotopes decay into the element thorium, which in turn decays into protactinium, and each has its own isotopes. Artemis Spyrou, The Conversation, 24 May 2022 Word History Etymology New Latin First Known Use 1918, in the meaning defined above Medical Definition protactinium noun prot·​ac·​tin·​i·​um ˌprōt-ˌak-ˈtin-ē-əm  variants also protoactinium ˌprōt-ō-  : a shiny metallic radioelement of relatively short life —symbol Pa see Chemical Elements Table
随便看	tiar tiara tiaras Tiarella tiarellae tiarellas Tiaris tiars tib Tibareni Tibbett tibbit Tibbu tibbus Tiber tiber green tiberes Tiberian Tiberias Tiberias, Lake tiberias, sea of Tiberius tibers Tibesti Mountains tibet

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