Signatures of the correlation hole in total and partial cross sections

In a complex scattering system with few open channels, say a quantum dot with leads, the correlation properties of the poles of the scattering matrix are most directly related to the internal dynamics of the system. We may ask how to extract these properties from an analysis of cross sections. In general this is very difficult, if we leave the domain of isolated resonances. We propose to consider the cross correlation function of two different elastic or total cross sections. For these we can show numerically and to some extent also analytically a significant dependence on the correlations between the scattering poles. The difference between uncorrelated and strongly correlated poles is clearly visible, even for strongly overlapping resonances.Comment: 25 pages, 13 Postscript figures, typos corrected and references adde

GLYOXAL TRIPLET'S SPECTROSCOPY BY ANTICROSSINGS IN STRONG MAGNETIC FIELD

$^{1}$ T.A. MILLER and R.S. FREUND, Magnetic Induced by Electrons in Advances in Magnetic Resonance. Editor J. WILEY and SONS. $^{2}$ P. DUPRE, R. JOST, M. LOMBARDI, to be submitted to Chem. Phys.Author Institution: Laboratoire de Spectrom\'{e}trie Physique, Service National des Champs Intenses - CNRSWe excite single rovibronic $S_{1}$ levels of the Glyoxal molecule (CHO CHO) with an $Ar^{+}$ pumped CW ring dye laser. The Glyoxal is cooled in a supersonic jet. We monitor unresolved fluorescence as a function of magnetic field up to 8 T (homogeneity $\delta B/B \sim 10^{-5}$ in $1 cm^{3}$). Anticrossing accurs when rotational levels of high vibrational states of $T_{1}$ are tuned by the field (Zeeman effect) across the singlet level excited by the laser. Selection rules for anticrossings are nearly identical to those for optical electric dipole transition ($\triangle N = 0, \pm 1,\ldots)^{1}$. The positions in magnetic field of the anticrossings enable us to deduce the triplet rotational structure and then to determine rotational $constants^{2}$. The resolution Doppler free spectroscopy is limited in principle only by the widths of the anticrossings. These are related to the singlet-triplet coupling $V_{st}$ which varies between the natural linewidth and $\sim 300$ MHz. In fact these anticrossings have fine and hyperfine structure. When the various peaks due to these structures overlap $(V_{st}>25 MHz)$ we use a microwave-optical double resonance method to resolve them. We are thus able in all cases to measure the fine and hyperfine structures of the triplet levels. We have noticed that the hyperfine structure is nearly constant for several hundreds of observed levels $(83 \pm 3 MHz)$. This contrasts with the fine structure which varies in an erratic manner. Experimental uncertainties are due entirely to the inhomogeneity of the field which we measure with an NMR probe. We have thus determined the rotational constants of several highly excited triplet vibrational levels located around $2 800 cm^{-1}$ and $3 500 cm^{-1}$ above the fundamental vibrational level of the electronic state $T_{1}$

Development of regionalized hydrological models in an area with short hydrological observation series

High spatio-temporal resolution monitoring has only been progressively developed in the Rhine–Meuse basins over the last few decades. As a consequence, basic hydrological information can be very scarce in some areas. In regions which are homogeneous from a hydroclimatological and physiogeographical point of view, hydrographs can be reproduced via regionalized hydrological models, provided that climatological observation series are available. The Alzette river basin, monitored since the mid-1990s by a very dense hydroclimatological observation network, had been chosen in the framework of the IRMA-SPONGE project FRHYMAP for transposing the conceptual hydrological models HRM and SOCONT and regionalizing their parameters. The regionalized models were to be used both for extending the currently available runoff series and evaluating runoff in neighbouring non-monitored basins. The 16 monitored sub-basins of the Alzette, reflecting the physiogeographical diversity of the study area, were divided into two subsets, serving for both the calibration and the validation procedures. Once the transposition of the models to the Alzette basin had been successfully assessed, their parameters were linked to the physiogeographical characteristics of the sub-basins. The performance of the thus regionalized models was assessed via a validation on a subset of basins that had not been retained for the elaboration of the regional parameter sets. The transposition of the HRM and SOCONT model to the Alzette river basin was completed successfully. Results overall proved to be satisfying, with the HRM model performing equally well for low flows and high flows, while the SOCONT model showed best results for high flows and a systematic overestimation of the mean discharge. Both models proved to be adequate for evaluating daily runoff in non-monitored basins of the Grand-Duchy of Luxembourg, helping thus to counterbalance the considerable lack of hydrological observation series in this part of the Rhine basin

Recherches sur l'évaluation des ressources en eau et des risques associés

The current report summarizes the results obtained by the Cemagref in 1992-1993 in the framework of the second year of the Environment Department - CEMAGREF general convention. The studies were related to three fields: - Research of operating describers in view of a typology of running water ecosystems, especially: conceptual and methodologic frame; hydro-ecoregions approach; describers of the variability of hydrological patterns ; modelling of fish habitat; invertebrates and trophic factors. - Bioindicators of the global quality of aquatic environments, especially: relationships between the sediment fauna (mollusks, oligochaetae) and the contamination of running waters, lakes and interstitial waters; use of the EROD dependent P450 enzymatic activity to diagnose toxic pollutions. - Hydrological and hydraulic modelling, especially: modelling of soil moisture content; regional hydrologic models with a large spatial scale validity: simulation of the propagation of a dam-break wave. / Le présent rapport résume les résultats acquis par le Cemagref dans les années 1992-1993 dans le cadre de deuxième annuité de la convention générale Ministère de l'Environnement - CEMAGREF. Les travaux ont porté sur trois domaines : - Recherche de descripteurs de fonctionnement en vue d'une typologie des écosystèmes d'eau courante, notamment : cadre conceptuel et méthodologique ; approche par hydro-écorégions ; descripteurs de la variabilité des régimes hydrologiques ; modélisation de l'habitat des poissons ; invertébrés et facteurs trophiques. - Bioindicateurs de la qualité globale des milieux aquatiques, notamment : relations entre la faune des sédiments (mollusques, oligochètes) et la contamination des eaux courantes, des lacs, et des eaux interstitielles ; utilisation de l'activité enzymatique P450 dépendante EROD pour diagnostiquer les pollutions toxiques. - Modélisation hydrologique et hydraulique, notamment : modélisation de l'humidité du sol ; modèles hydrologiques régionaux à large validité d'échelle spatiale ; simulation de la propagation d'une onde de rupture de barrage

Monitoring Wind, Turbulence and Aircraft Wake Vortices by High Resolution RADAR and LIDAR Remote Sensors in all Weather Conditions

International audienceAir flows in the troposphere have a major impact on air traffic safety and operations. By air flows, several phenomena can be distinguished with different spatial and temporal characteristic scales: the mean wind itself, its rapid fluctuations, called turbulence, and wake vortices which are structured motions generated by each aircraft. At low altitudes, during take-off or landing phases, distance separations between aircrafts that limit today airport capacities were set up forty years ago to prevent the rik of wake vortices encounters in worst conditions. These out of date distance separations must be optimized since strength and lifetime of wake vortices vary a lot with weather conditions, like winds and turbulence. At high altitudes, during en-route flight phase, wake vortices as well as clear air turbulence can have a dramatic impact on aircraft safety. In this study, the way to measure wind, turbulence and wake vortices with new remote sensing techniques, 1.5 micron Coherent Doppler LIDAR, X-Band RADAR, and UV direct detection LIDAR, is detailed for ground-based or airborne applications. Sensor simulation tools and post-processing algorithms have been developed to retrieve wind, turbulence, especially EDR (eddy dissipation rate) and wake vortices parameters from sensors data and to assess their accurac