Scientists from the University of Missouri, USA created miniature nuclear power sources, the size of which does not exceed a small USB flash drive. An article about this was published by the scientific journal Journal of Applied Physics and Journal of Radioanalytical and Nuclear Chemistry. The principle of operation of the device is similar to the principle on which radioisotope energy sources act, in which the thermal energy of decay is converted into electrical energy. In the new device, the radioactive element is located in the liquid semiconductor. Particles resulting from radioactive decay in it cause an electric current to appear in the semiconductor. The advantage of such a power source is 1000000 times greater specific capacity compared to conventional chemical power sources.