How did de broglie conclude that electrons have a wave nature

The French physicist Louis De Broglie proposed the existence of matter waves, that is to say that all matter has a wave associated with it.  

On the other hand, Heisenberg enunciated the uncertainty principle, which postulates that the fact that each particle has a wave associated with it, imposes restrictions on the ability to determine its position and speed at the same time.  

These postulations were tested with the double slit experiment (formerly applied to photons) applied to electrons, and the result was: electrons (as well as the other particles different from the photons) are able to behave as waves.

increasing transnational kinetic energy. because the transnational kinetic energy formula consists of only two variables, mass and velocity, increasing one of those properties is the only way to increase an object's transnational kinetic energy. increases to mass and velocity, however, do not have the same impact.

an energy transformation flow diagram is shown

where is it ?