The X-ray Correlation Spectroscopy instrument at the Linac Coherent Light Source.

The X-ray Correlation Spectroscopy instrument is dedicated to the study of dynamics in condensed matter systems using the unique coherence properties of free-electron lasers. It covers a photon energy range of 4-25 keV. The intrinsic temporal characteristics of the Linac Coherent Light Source, in particular the 120 Hz repetition rate, allow for the investigation of slow dynamics (milliseconds) by means of X-ray photon correlation spectroscopy.

Gravity-driven instability of a thin liquid film underneath a soft solid.

The gravity-driven instability of a thin liquid film located underneath a soft solid material is considered. The equations and boundary conditions governing the solid deformation are systematically converted from a Lagrangian representation to an Eulerian representation, which is the natural framework for describing the liquid motion. This systematic conversion reveals that the continuity-of-velocity boundary condition at the liquid-solid interface is more complicated than has previously been assumed, even in the small-strain limit.

The economics of short-term leasing.

Short-term leasing is an everyday occurrence. Tax savings cannot account for the ubiquity of leasing by temporary users. Monopoly explanations are inconsistent with concurrent leasing and selling markets for perfect substitutes.