Complex sentence: Yang has had a great interest in statistical mechanics since his undergraduate era, in the 1950s and 1960s, collaborated with T.D. LeeTsung-Dao Lee and Kerson Huang, etc. he studied statistical mechanics and condensed matter theory.
Split into simpler sentences: Yang has had a great interest in statistical mechanics since his undergraduate time. In the 1950s and 1960s, he collaborated with T.D. Lee and Kerson Huang, etc. and studied statistical mechanics and condensed matter theory.