. "2018-02-12 16:53:18.0" . "SDN:P07::2YHO1NVH" . "" . "1" . . "SDN:P07::2YHO1NVH" . "accepted"@en . . "false" . "SDN:P07::2YHO1NVH" . "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. \"Rn\" means the element \"radon\" and \"222Rn\" is the isotope \"radon-222\" with a half-life of 3.82e+00 days."@en . . . "2018-02-12 16:53:18.0" . "surface_radioactivity_content_of_222Rn"@en . "1" . .