  Charging effects in mesoscopic junctions suppress the tunneling of electrons.
In normal metal - superconductor systems they also suppress the proximity
effect, thereby revealing the nature of the microscopic processes and of the
ground state of the system. The effect can be made visible since the charging
and proximity effect and hence the transport properties of the system can be
modulated by gate voltages. If the superconducting electrode is isolated,
electron number parity effect lead to an even-odd asymmetry in the proximity
effect.
