get rid of special characters "^@"

hi,

i used method tostring to convert a double into string and have written in a file,

while i try to open the file in shell(unix), it shows some special characters as follows,

^@0^@.^@0^@4^@3^@7^@4^@0^@7^@

^@0^@.^@0^@3^@1^@3^@1^@9^@2^@

^@0^@.^@0^@1^@6^@5^@0^@2^@9^@

^@0^@.^@0^@0^@3^@1^@8^@5^@5^@1^@

in between each numbers, when i open the same file in textedit it shows as follows,

0

[440 byte] By [prasadgunasa] at [2007-11-27 8:00:52]