{"aspect_id":"AS121","aspect_name":"refractive-index","aspect_reference":null,"aspect_symbol":"n","name":"refractive-index parts per million","scale_id":"SC1358","scale_name":null,"scale_symbol":null,"scale_type":"ratio","symbol":"n ppm","unit_id":"UN1270","unit_name":"parts per million","unit_reference":null,"unit_symbol":"ppm"}