[电] mean-time-to-first failure

shǒu cì shī bài píng jūn shí jiān ㄕㄡˇ ㄘˋ ㄕ ㄅㄞˋ ㄆㄧㄥˊ ㄐㄩㄣ ㄕˊ ㄐㄧㄢ