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           __   __  __    __   __   __    _____   
    ___    \ \\/ // \ \\ / //  \ \\/ //  |__  //  
   /   ||   \ ` //   \ \/ //    \ ` //     / //   
  | [] ||    | ||     \  //      | ||     / //__  
   \__ ||    |_||      \//       |_||    /_____|| 
    -|_||    `-`'       `        `-`'    `-----`  
     `-`

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發送短信 : The compound equation related to the Bessel-Helmholtz equation and the Bessel-Klein-Gordon equation