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  _____    __   __   _    _    _    _    __   _   
 / ____||  \ \\/ // | \  / || | || | || | || | || 
/ //---`'   \ ` //  |  \/  || | || | || | '--' || 
\ \\___      | ||   | .  . || | \\_/ || | .--. || 
 \_____||    |_||   |_|\/|_||  \____//  |_|| |_|| 
  `----`     `-`'   `-`  `-`    `---`   `-`  `-`

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發送短信 : Ultrasonic wave propagation in non homogeneous media