notable physicists and inventors also include: horia hulubei in atomic physics, șerban țițeica in theoretical physics, mihai gavrilă specialized in quantum theory and discoverer of the atomic dichotomy phenomenon, alexandru proca (known for the first meson theory of nuclear forces and proca's equations of the vectorial mesonic field), ştefan procopiu known for the first theory of the magnetic moment of the electron in 1911 (now known as the bohr-procopiu magneton), theodor v. ionescu, the inventor of a multiple-cavity magnetron (1935), a hydrogen maser in 1947, 3d imaging for cinema/television in 1924 and hot deuterium plasma studies for controlled nuclear fusion, ionel solomon known for the nuclear magnetic resonance theory in solids, solomon equations and photovoltaic devices, petrache poenaru, nicolae teclu and victor toma, with the latter known for the invention and construction of the first romanian computer, the cifa-1 in 1955.