U.S. President Barack Obama laughs as he awards Dr. Sylvester James Gates from University of Maryland with the National Medal of Science during a ceremony at the White House in Washington D.C., the United States, on Feb. 1, 2013. (Xinhua/Fang Zhe)

U.S. President Barack Obama awards Dr. Art Rosenfeld (L) from Lawrence Berkeley National Laboratory with the National Medal of Technology and Innovation during a ceremony at the White House in Washington D.C., the United States, on Feb. 1, 2013. (Xinhua/Fang Zhe)

U.S. President Barack Obama speaks during a ceremony to award National Medal of Science and National Medal of Technology and Innovationat at the White House in Washington D.C., the United States, on Feb. 1, 2013. (Xinhua/Fang Zhe)

U.S. President Barack Obama speaks during a ceremony to award National Medal of Science and National Medal of Technology and Innovationat at the White House in Washington D.C., the United States, on Feb. 1, 2013. (Xinhua/Fang Zhe)