Array ( [0] => Array ( [title] => L30A [link] => https://www.youtube.com/embed/8QAwvJR8ySk ) [1] => Array ( [title] => L30B [link] => https://www.youtube.com/embed/O0OVQb6-hD0 ) ) 國立清華大學開放式課程OpenCourseWare(NTHU, OCW) - 第30講 The Interconversion of Mass and Energy