Angle-resolved reflection inelastic electron scattering has been used to measure the dispersion of the surface plasmon for thick films of Na and K. The measured dispersion is negative at small momentum parallel to the surface as predicted by quantum-mechanical calculations of the dynamic response of the electrons at the surface of an interacting electron gas. A simple physical picture is presen...

Heavy nitrogen (N2) 1 is often used as a label for nitrogen Wxation experiments in which it is desirable to monitor directly the rate of nitrogen Wxation and the destination of the resulting metabolites in an organism or ecosystem [1–4]. Heavy nitrogen can be purchased in a pressurized cylinder or produced in the laboratory with specialized equipment, but both methods of obtaining the gas are e...

Using an angle-resolved heterodyne four-wave-mixing technique, we probe the low momentum excitation spectrum of a coherent polariton gas. The experimental results are well captured by the Bogoliubov transformation which describes the transition from single particle excitations of a normal fluid to soundlike excitations of a superfluid. In a dense coherent polariton gas, we find all the characte...

In a sample of local active galactic nuclei studied at a spatial resolution on the order of ten parsecs we show that the interstellar medium traced by the molecular hydrogen ν=1-0 S(1) line at 2.1 μm forms a geometrically thick, clumpy disk. The kinematics of the molecular gas reveals general rotation, although an additional significant component of random bulk motion is required by the high lo...

Gas hydrate growth kinetics was studied at a pressure of 90 bars to investigate the effect of temperature, initial water content, stirring rate, and reactor size in stirred semi-batch autoclave reactors. The mixing energy during hydrate growth was estimated by logging the power consumed. The theoretical model by Garcia-Ochoa and Gomez for estimation of the mass transfer parameters in stirred ta...