1959年6月,苏联单方面撕毁协议,拒绝援助我国研制原子弹,1960年7月,撤走了全部在华专家,带走了图纸和资料。有的专家说:“这是对你们的毁灭性打击”;“再过两年,你们只好卖废铜烂铁了”;“从此你们将处于技术真空状态,估计20年后你们也搞不出来原子弹”。正在苏联杜布纳联合研究所工作的周光召、吕敏、何祚庥等中 In June 1959, the Soviet Union unilaterally broke the agreement and refused to aid China in the development of an atomic bomb. In July 1960, all the experts in China withdrew and took away the drawings and materials. Some experts say: “This is a devastating blow to you.” “In two years, you have to sell iron and steel scrap.” “From then on, you will be in a state of technical vacuum. After an estimated 20 years, You also can not come out the atomic bomb. ” Zhou Guangzhao, Lu Min, He Zuole and others who are working at the Joint Institute of Dubna in the Soviet Union