title: Conversion of Japanese "semi-voice" character
body: <p>I was trying to compare two spark dataframe which contains Japanese characters and there's some characters that seem the same but actually different to the program, such as プ vs プ</p>
  <p>If you put them in utf-8 encoder:</p>
  <p>プ utf-8 = \xE3\x83\x97</p>
  <p>プ utf-8 = \xE3\x83\x95\xE3\x82\x9A</p>
  <p>Looks like フ(\xE3\x83\x95) + the little circle semi-voice sign(\xE3\x83\x95) = プ</p>
  <p>What are these difference called, and is there any way to convert between them in Java/Scala?</p>
  <p>Thank you.</p>