"accepted"@en . "1" . . "1" . . "2018-02-12 16:53:18.0" . . "The surface called \"surface\" means the lower boundary of the atmosphere. \"Content\" indicates a quantity per unit area. \"Radioactivity\" means the number of radioactive decays of a material per second. \"U\" means the element \"uranium\" and \"234U\" is the isotope \"uranium-234\" with a half-life of 9.02e+07 days."@en . "SDN:P07::49GDOO4E" . . "surface_radioactivity_content_of_234U"@en . . "2018-02-12 16:53:18.0" . "SDN:P07::49GDOO4E" . . "" . "false" . "SDN:P07::49GDOO4E" .