"1" . . "accepted"@en . "" . "1" . . "2018-02-12 16:53:18.0" . "SDN:P07::4KYNIHSD" . . . "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. \"Sm\" means the element \"samarium\" and \"148Sm\" is the isotope \"samarium-148\" with a half-life of 2.92e+18 days."@en . "false" . . "surface_radioactivity_content_of_148Sm"@en . "2018-02-12 16:53:18.0" . "SDN:P07::4KYNIHSD" . . "SDN:P07::4KYNIHSD" .