"1" . . "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. \"Pr\" means the element \"praseodymium\" and \"147Pr\" is the isotope \"praseodymium-147\" with a half-life of 8.33e-03 days."@en . "SDN:P07::68E18PKZ" . "" . . . "false" . "accepted"@en . . "2018-02-12 16:53:18.0" . . "surface_radioactivity_content_of_147Pr"@en . "SDN:P07::68E18PKZ" . "SDN:P07::68E18PKZ" . "1" . "2018-02-12 16:53:18.0" . .