Substantial work in the field was carried out by the Shanghai-born American physicists An Wang and Way-Dong Woo, who created the "pulse transfer controlling device" in 1949. The name referred to the way that the magnetic field of the cores could be used to control the switching of current; his patent focused on using cores to create delay-line or shift-register memory systems. Wang and Woo were working at Harvard University's Computation Laboratory at the time, and the university was not interested in promoting inventions created in their labs. Wang was able to patent the system on his own.