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  ______     ___     _    _      ___      ______  
 /_   _//   / _ \\  | |  | ||   / _ \\   /_   _// 
   | ||    | / \ || | |/\| ||  / //\ \\    | ||   
  _| ||    | \_/ || |  /\  || |  ___  ||  _| ||   
 /__//      \___//  |_// \_|| |_||  |_|| /__//    
 `--`       `---`   `-`   `-` `-`   `-`  `--`

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發送短信 : Symmetry groups of single-wall nanotubes