Flexible Field Emitter for X-ray Generation by Implanting CNTs into Nickel Foil

the article is published twice in the journal: volume 11 article number 326 (https://doi.org/10.1186/s11671-016-1523-5) and volume 11 article number 393 (https://doi.org/10.1186/s11671-016-1598-z); both have been retracted (see also: https://retractiondatabase.org/RetractionEdit.aspx?RID=21944);