We present results on deep sub threshold hyperon production in nuclear collisions, with the UrQMD transport model. Introducing anti-kaon+baryon and hyperon+hyperon strangeness exchange reactions we obtain a good description of experimental data on single strange hadron production in Ar+KCl reactions at E lab = 1.76 A GeV. We find that the hyperon strangeness exchange is the dominant process contributing to the Ξ − yield, however remains short of explaining the Ξ − /Λ ratio measured with the HADES experiment. We also discuss possible reasons for the discrepancy with previous studies and the experimental results, finding that many details of the transport simulation may have significant effects on the final Ξ − yield.

Nanoscale gated quantum wires in GaAs MODFET material with the conduction channel and gates in the plane of the 2DEG have been fabricated and studied. Electron beam lithography was used for mask definition followed by flood exposure to low energy argon ions (150 eV) for pattern transfer into the 2DEG. Compared to metal top-gate designs the in-plane design simplifies fabrication and reduces device capacitance, promising ultra-fast operation. This method of pattern transfer produced devices having channel-to-gate isolation of 1014 Ω and breakdown fields above 106 V/cm at 4.2 K. In addition to exhibiting standard FET characteristics, including gating to pinchoff, the devices showed significant negative differential resistance (NDR) in the saturation region.