Jensen, YEHN zuhn, J. Hans (1907-1973), a German physicist, shared the 1963 Nobel Prize in physics with Maria Goeppert Mayer and Eugene Paul Wigner. Working independently, Jensen and Mayer prepared almost identical papers on the shell structure of atomic nuclei. Their work, published in 1949, showed that atomic nuclei possess shells similar to the electron shells of atoms. The shells contain varying numbers of protons and neutrons. This permits a systematic arrangement of nuclei according to their properties. It also explains why some nuclei are stable and others are not.