[电] electron-stream transmission efficiency

diàn zǐ liú chuán shū xiào lǜ ㄉㄧㄢˋ ㄗˇ ㄌㄧㄡˊ ㄔㄨㄢˊ ㄕㄨ ㄒㄧㄠˋ lv4