Fundamental Limits of "Ankylography" due to Dimensional Deficiency

Single-shot diffractive imaging of truly 3D structures suffers from a dimensional deficiency and does not scale. The applicability of "ankylography" is limited to objects that are small-sized in at least one dimension or that are essentially 2D otherwise.Comment: 2 pages, no figur

Lattice Gas Automata for Reactive Systems

Reactive lattice gas automata provide a microscopic approachto the dynamics of spatially-distributed reacting systems. After introducing the subject within the wider framework of lattice gas automata (LGA) as a microscopic approach to the phenomenology of macroscopic systems, we describe the reactive LGA in terms of a simple physical picture to show how an automaton can be constructed to capture the essentials of a reactive molecular dynamics scheme. The statistical mechanical theory of the automaton is then developed for diffusive transport and for reactive processes, and a general algorithm is presented for reactive LGA. The method is illustrated by considering applications to bistable and excitable media, oscillatory behavior in reactive systems, chemical chaos and pattern formation triggered by Turing bifurcations. The reactive lattice gas scheme is contrasted with related cellular automaton methods and the paper concludes with a discussion of future perspectives.Comment: to appear in PHYSICS REPORTS, 81 revtex pages; uuencoded gziped postscript file; figures available from [email protected] or [email protected]

Coupling of thermal and mass diffusion in regular binary thermal lattice-gases

We have constructed a regular binary thermal lattice-gas in which the thermal diffusion and mass diffusion are coupled and form two nonpropagating diffusive modes. The power spectrum is shown to be similar in structure as for the one in real fluids, in which the central peak becomes a combination of coupled entropy and concentration contributions. Our theoretical findings for the power spectra are confirmed by computer simulations performed on this model.Comment: 5 pages including 3 figures in RevTex

Modal beam splitter:Determination of the transversal components of an electromagnetic light field

The transversal profile of beams can always be defined as a superposition of orthogonal fields, such as optical eigenmodes. Here, we describe a generic method to separate the individual components in a laser beam and map each mode onto its designated detector with low crosstalk. We demonstrate this with the decomposition into Laguerre-Gaussian beams and introduce a distribution over the integer numbers corresponding to the discrete orbital and radial momentum components of the light field. The method is based on determining an eigenmask filter transforming the incident optical eigenmodes to position eigenmodes enabling the detection of the state of the light field using single detectors while minimizing cross talk with respect to the set of filter masks considered.UK Engineering and Physical Sciences Research Council [EP/J01771X/1]This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Cellular Automata Simulating Experimental Properties of Traffic Flows

A model for 1D traffic flow is developed, which is discrete in space and time. Like the cellular automaton model by Nagel and Schreckenberg [J. Phys. I France 2, 2221 (1992)], it is simple, fast, and can describe stop-and-go traffic. Due to its relation to the optimal velocity model by Bando et al. [Phys. Rev. E 51, 1035 (1995)], its instability mechanism is of deterministic nature. The model can be easily calibrated to empirical data and displays the experimental features of traffic data recently reported by Kerner and Rehborn [Phys. Rev. E 53, R1297 (1996)].Comment: For related work see http://www.theo2.physik.uni-stuttgart.de/helbing.html and http://traffic.comphys.uni-duisburg.de/member/home_schreck.htm

Adjunctive granulocyte colony-stimulating factor for treatment of septic shock due to melioidosis

1427 E 60TH ST, CHICAGO, USA, IL, 60637-295

Dynamic modelling of electrooptically modulated vertical compound cavity surface emitting semiconductor lasers

A generalized rate equation model is used to simulate the interrelated amplitude and frequency modulation properties of Electrooptically Modulated Vertical Compound Cavity Surface Emitting Semiconductor Lasers in both large and small signal modulation regimes. It is shown that the photon lifetime in the modulator subcavity provides the ultimate limit for the 3 dB modulation cutoff frequency. It is shown that there is an optimum design (number of periods) of both the intermediate and top multistack reflectors to maximise the large-signal modulation quality

Amplification du champ proche par résonance plasmonique pour la spectroscopie Raman et la photocatalyse.

La spectroscopie Raman exaltée par effet de pointe (TERS) combine la haute résolution produite par la spectroscopie à force atomique (AFM) et l’étude des modes de vibration produites par la spectroscopie Raman. Il s’agit d’une technique à haute sensibilité qui permet la détection des molécules à très faibles concentrations et de fournir une riche information sur la structure ainsi que sur la composition chimique. En tant que technique polyvalente il y’a presque 40 ans de recherches, TERS peut non seulement répondre à des questions scientifiques fondamentales, mais aussi de résoudre des problèmes d'ingénierie dans de nombreuses applications. Cependant, dans tous les cas, le substrat plasmonique présente le composant le plus critique dans ce domaine. La détection de TERS est fortement dépendante du substrat, où l'excitation des plasmons de surface localisés (LSP) augmente les signaux de diffusion Raman des molécules à proximité de la surface étudiée. Dans cette thèse, nous avons d'abord utilisé la spectroscopie Raman exaltée par effet de surface (SERS) pour étudier la surface plasmonique qui est composée de différentes formes de nanostructures plasmoniques. Nous avons discuté l’ordre de grandeur de l’exaltation du champ électromagnétique et le décalage de la résonance dans des matériaux plasmoniques de base, tels que les nanoparticules métalliques, les nanobâtons, les nanotriangles préparés par des procédés de synthèse lithographiques. La corrélation entre les points chauds qui apparaissent entre les nanoparticules plasmoniques et les sites catalytiques a présenté toujours un débat dans la communauté scientifique. Comme solution, nous avons développé une technique avancée de TERS nommé Spectroscopie Raman exaltée par effet de pointe fonctionnalisée (F-TERS). Nous avons ainsi examiné expérimentalement des nanostructures plasmoniques avec des pointes en or fonctionnalisées avec des molécules de 4-nitrothiophénol active en Raman pour fournir une exaltation du champ intense en TERS. Nous avons discuté après des progrès de recherche de la cartographie chimique des nanostructures plasmoniques présentant des réactions photocatalytiques à leur surface. Nous avons trouvé une bonne corrélation entre les points chauds des nanostructures plasmoniques qui sont dues à l’effet de l’exaltation du champ électromagnétique par effet de surface et leur capacité photocatalytique

Metal-ligand bonding in six-coordinate d-block complexes probed by luminescence spectroscopy at variable pressure

Luminescence spectra measured at variable pressure can reveal unique insight on ground- and emitting state properties of transition metal compounds. This chapter summarizes illustrative results for chromium(III) complexes with the d3 electron configuration and oxo complexes of rhenium(V) and molybdenum(IV) with the d2 configuration. Their luminescence transitions only involve electronic configuration changes within the t2 (O point group) molecular orbitals, leading to narrow spin-flip bands and broad bands with vibronic structure for the chromium(III) and metal-oxo complexes, respectively