Hideki Yukawa ForMemRS FRSE was born on this date in 1907. He was a Japanese theoretical physicist and the first Japanese Nobel laureate. He was born as Hideki Ogawa in Tokyo and grew up in Kyoto. In 1929, after receiving his degree from Kyoto Imperial University, he stayed on as a lecturer for four years. After graduation, he was interested in theoretical physics, particularly in the theory of elementary particles. In 1932, he married Sumi Yukawa, and his family name was changed to Yukawa; they had two sons, Harumi and Takaaki. In 1933 he became an assistant professor at Osaka University. In 1935 he published his theory of mesons, which explained the interaction between protons and neutrons and was a major influence on research into elementary particles. In 1940 he became a professor at Kyoto University. In 1940 he won the Imperial Prize of the Japan Academy, in 1943 the Decoration of Cultural Merit from the Japanese government. In 1949 he became a professor at Columbia University, the same year he received the Nobel Prize in Physics, after the discovery in 1947 by Cecil Frank Powell, Giuseppe Occhialini and César Lattes of Yukawa’s predicted pions. Yukawa also worked on the theory of K-capture, in which a low energy electron is absorbed by the nucleus, after its initial prediction by G. C. Wick. Yukawa became the first chairman of Yukawa Institute for Theoretical Physics in 1953. He received a Doctorate, honoris causa, from the University of Paris and honorary memberships in the Royal Society, Royal Society of Edinburgh, the Indian Academy of Sciences, the International Academy of Philosophy and Sciences, and the Pontificia Academia Scientiarum. He was an editor of Progress of Theoretical Physics and published the books Introduction to Quantum Mechanics (1946) and Introduction to the Theory of Elementary Particles (1948). In 1955, he joined ten other leading scientists and intellectuals in signing the Russell–Einstein Manifesto, calling for nuclear disarmament. Yukawa retired from Kyoto University in 1970 as a Professor Emeritus. Owing to increasing infirmity in his final years, he appeared in public in a wheelchair. He died at his home in Sakyo-Ku, Kyoto, on 8 September 1981 from pneumonia and heart failure, aged 74. His tomb is in Higashiyama-Ku, Kyoto.
Otto Paul Hermann Diels was born on this date in 1876. He was a German chemist. His most notable work was done with Kurt Alder on the Diels–Alder reaction, a method for diene synthesis. The pair was awarded the Nobel Prize in Chemistry in 1950 for their work. Their method of synthesising cyclic organic compounds proved valuable for the manufacture of synthetic rubber and plastic. He completed his education at the University of Berlin, where he later worked. Diels was employed at the University of Kiel when he completed his Nobel Prize–winning work, and remained there until he retired in 1945. Diels was married, with five children. He died in 1954.