SDHC date lose,help!help~!

["Miracle Liu" <miracle.liuyx@gmail.com>]

It's installed Debian Sid which is my SDHC.When i run "apt-get dist-upgrade",in this time power off. when i poweron ,i see my SDHC is borcken.

now i run -> #fdisk /dev/sdb               show:Unable to read /dev/sdb
                  #gpart /dev/sdb               show:*** Fatal error: cannot get sector size on dev(/dev/sdb)
                  #gpart /dev/sdb -s 63       show:*** Fatal error: failed trying to use sector size 63.
                  #cat /dev/sdb | less         show:cat: /dev/sdb:  io error

who can help me!!!!~~~~