Interface-Induced Plasmon Nonhomogeneity in Nanostructured Metal-Dielectric Planar Metamaterial

Transformations of the electronic structure in thin silver layers in metal-dielectric (TiAlN/Ag) multilayer nanocomposite were investigated by a set of electron spectroscopy techniques. Localization of the electronic states in the valence band and reduction of electron concentration in the conduction band was observed. This led to decreasing metallic properties of silver in the thin films. A critical layer thickness of 23.5 nm associated with the development of quantum effects was determined by X-ray photoelectron spectroscopy. Scanning Auger electron microscopy of characteristic energy losses provided images of plasmon localization in the Ag layers. The nonuniformity of plasmon intensities distribution near the metal-nitride interfaces was assessed experimentally

Nonlinear dynamics in one dimension: On a criterion for coarsening and its temporal law

We develop a general criterion about coarsening for a class of nonlinear evolution equations describing one dimensional pattern-forming systems. This criterion allows one to discriminate between the situation where a coarsening process takes place and the one where the wavelength is fixed in the course of time. An intermediate scenario may occur, namely `interrupted coarsening'. The power of the criterion lies in the fact that the statement about the occurrence of coarsening, or selection of a length scale, can be made by only inspecting the behavior of the branch of steady state periodic solutions. The criterion states that coarsening occurs if lambda'(A)>0 while a length scale selection prevails if lambda'(A)<0, where $lambda$ is the wavelength of the pattern and A is the amplitude of the profile. This criterion is established thanks to the analysis of the phase diffusion equation of the pattern. We connect the phase diffusion coefficient D(lambda) (which carries a kinetic information) to lambda'(A), which refers to a pure steady state property. The relationship between kinetics and the behavior of the branch of steady state solutions is established fully analytically for several classes of equations. Another important and new result which emerges here is that the exploitation of the phase diffusion coefficient enables us to determine in a rather straightforward manner the dynamical coarsening exponent. Our calculation, based on the idea that |D(lambda)|=lambda^2/t, is exemplified on several nonlinear equations, showing that the exact exponent is captured. Some speculations about the extension of the present results to higher dimension are outlined.Comment: 16 pages. Only a few minor changes. Accepted for publication in Physical Review

Plasma Catalytic Reforming of Natural Gas

In this paper, recent results of plasma processing of natural gas are described. The use of a plasma reformer for the generation of hydrogen rich gas from natural gas has been investigated. In an accompanying paper, progress in plasma reforming of diesel fuel is described. The reformate composition has been investigated as a function of the initial mixture of air and methane. High methane conversion, near 100%, was obtained at relatively low values of plasmatron power. Soon-to-be-implements improvements in the overall reformer, including multiple heat exchanger for efficient thermal management and multiple water shift reactors, are described. 1

Plasma Reforming of Diesel Fuel

The use of a plasma reformer for the generation of hydrogen rich gas from diesel fuel has been investigated. A system that is normally used for investigating natural gas reforming has been modified in order to investigate the reforming of heavy liquid fuels. The composition of the reformate has been investigated as a function of the composition of the reagents. The use of a one-step reformer/water shifter was studied. Good reforming, with no noticeable soot production, was obtained. The specific energy consumption was equal to that previously obtained with methane reforming, with much reduced concentration of methane in the reformate. 1. Introduction. Thermal plasma technology can be efficiently used in the production of hydrogen and hydrogen-rich gases from methane and a variety of fuels [1-3]. The thermal plasma is a highly energetic state of matter that is characterized by extremely high temperatures (several thousand degrees Celsius) and high degree of dissociation and substantial degree of ionization. The hig

Onboard Plasmatron Generation of Hydrogen Rich Gas for Diesel Engine Exhaust Aftertreatment and Other Applications

Plasmatron reformers can provide attractive means for conversion of diesel fuel into hydrogen rich gas. The hydrogen rich gas can be used for improved NOx trap technology and other aftertreatment applications