High-pressure Optical Study of f-d Hybridization in UxLa1-xS Single Crystals

The optical reflectivity of UxLa1xS single crystals has been measured in a diamond-anvil cell for pressures up to 40 GPa. From a fit of the reflectivity spectra with one Drude term and three Lorentz oscillators the energies, intensities and widths of optical transitions are derived. In contrast to the expectation in an itinerant picture, the plasma frequencies decrease with increasing pressure, indicating the dominance of f–d hybridization effects. The nonmonotonic variation with x of the plasma frequencies and the oscillator strengths of interband transitions supports the model of the simultaneous presence of localized and itinerant 5f states in UxLa1xS.JRC.E.6-Actinides researc

Liquid Metals as Efficient High-Temperature Heat-Transport Fluids

Liquid metals appear to be attractive heat-transport fluids, in particular if looking at their high thermal conductivities and low viscosities. Despite some pioneering technical applications in the past, complex handling, special requirements, safety concerns, and structural degradation of the materials have prevented their widespread application. However, progress in research and development on liquid-metal science and technology has advanced considerably in the last decade, and this has opened the gate to their broader use in the short term. This requires a more differentiated view on liquid metals, particularly on the specific properties of individual fluids within the context of specific applications. By doing so, many commonly mentioned prejudices vanish or are of minor significance. At the Karlsruhe Institute of Technology, a comprehensive research program on liquid-metal technology has been pursued for more than 50years, and some of the advances in different applications will be outlined in this article