Frédéric Joliot-Curie
Yuasa was inspired by the discovery of artificial radioactivity by Irène and Frédéric Joliot-Curie at the Radium Institute in Paris. Because of difficult research conditions in Tokyo, Yuasa moved to Paris in 1940, even though the Second World War had just begun in Europe. She worked under Frédéric Joliot-Curie at the Collège de France, where she researched the alpha and beta particles emitted by artificial radioactive nuclei and the energy spectrum of beta particles. With her thesis, titled "Contribution à l'étude du spectre continu des rayons β− émis par les corps radioactifs artificiels" (Continuous beta-ray spectrum generated by artificial radioactivity), she earned a doctorate in science in 1943.