An electric energy exchange system between at least one motor-generator system and at least one storage member determining a continuous storage voltage between two branches of a bus circuit on which are connected in parallel a DCDC converter, a filtering capacity, and a DCAC converter connected on at least one motor-generator system. In certain embodiments, the wing is self-adapting according to air flow over the vehicle. In devices having GaN-based semiconductor layers with a wurtzite crystal structure, the growth orientation of the strained quantum well layer is tilted at least 1 from the 0001 direction of the wurtzite crystal structure. When a file is migrated from the upper tier to the lower tier, a stub file is stored in place of the migrated file indicating a storage location of the migrated file on the second storage system. In accordance with a further enhancement, the slide ejector mechanism may include structures that render the apparatus self-cleaning of broken slides.