Yasuhiko Arakawa Yasuhiko Arakawa Yasuhiko Arakawa (Japanese , "Arakawa Yasuhiko"; born 6 November 1952) is a Japanese physicist. His research focuses on semiconductor physics, including growth of nanostructures and their optoelectronic applications. Among his main achievements are the proposal of the concept of quantum dots and their application to quantum dot lasers, the observation of exciton-polariton Rabi-splitting in a semiconductor microcavity, or, recently, the first 3D photonic crystal nanocavity lasers with quantum dot gain. Yasuhiko Arakawa received a B.S. degree in 1975 and a Ph.D. degree in 1980, respectively, from the University of Tokyo, both in Electronics Engineering. In 1981 he became
Japanese gunboat Sumida (1939) Japanese gunboat Sumida (1939) "Sumida" was the second of two vessels in the river gunboats authorized under the 3rd Naval Armaments Supplement Programme of 1937. "Sumida" had a hull with an overall length of and width of , with a normal displacement of 338 tons and draft of . She was propelled by two Kampon steam turbine engines with two boilers driving two shafts, producing and had a top speed of 17 knots. The ship was armed with one /28 cal. gun and one 25mm machine gun. " Sumida" was laid down on 13 April 1939 and launched 30 October