when, in 1946 the three universities returned to beijing, feng instead went to the u.s. again, this time to take up a post as visiting professor at the university of pennsylvania. he spent the year 1948–1949 as a visiting professor at the university of hawaii. he served as president of tsinghua university from december 1948 to may 1949 because of zhang dongsun's refusal (it was known as national tsinghua university until january 1949).