RESUMEN
Recombination of the carrier due to the surface state level traps could affect betavoltaic performance. Herein, we employed a theoretical 1-D carrier transport calculation to investigate the surface passivation effect in a planar [147Pm]-Si p-n junction betavoltaic cell and the results were verified using previous studies. In comparison to the ideal condition of the passivated surface, we predict a 10.74% power loss at the device, thus further research concerning the surface passivation layer for betavoltaic batteries might be necessary.
RESUMEN
We present experimental evidence for a "granular clock." We use a setup in which vertical vibrations (10-20 Hz) of a bidisperse granular medium cause horizontal oscillations (periods in the order of minutes) between two connected compartments. Moreover, we present the first experimental evidence for full segregation of smaller particles into one compartment, leaving the larger ones in the other compartment. Simulations, using a simple model, describe phenomenologically the observed oscillations.