Search results for "78"

Theoretical study of resonant x-ray emission spectroscopy of Mn films on Ag.

2006

We report a theoretical study on resonant x-ray emission spectra (RXES) in the whole energy region of the Mn $L_{2,3}$ white lines for three prototypical Mn/Ag(001) systems: (i) a Mn impurity in Ag, (ii) an adsorbed Mn monolayer on Ag, and (iii) a thick Mn film. The calculated RXES spectra depend strongly on the excitation energy. At $L_3$ excitation, the spectra of all three systems are dominated by the elastic peak. For excitation energies around $L_2$, and between $L_3$ and $L_2$, however, most of the spectral weight comes from inelastic x-ray scattering. The line shape of these inelastic ``satellite'' structures changes considerably between the three considered Mn/Ag systems, a fact tha…

Development of a PbWO 4 detector for single-shot positron annihilation lifetime spectroscopy at the GBAR experiment

2020

International audience; We have developed a PbWO 4 (PWO) detector with a large dynamic range to measure the intensity of a positron beam and the absolute density of the ortho-positronium (o-Ps) cloud it creates. A simulation study shows that a setup based on such detectors may be used to determine the angular distribution of the emission and reflection of o-Ps to reduce part of the uncertainties of the measurement. These will allow to improve the precision in the measurement of the cross section for the (anti) hydrogen formation by (anti) proton-positronium charge exchange and to optimize the yield of antihydrogen ion which is an essential parameter in the GBAR experiment.

Monotonically convergent optimal control theory of quantum systems with spectral constraints on the control field

2009

We propose a new monotonically convergent algorithm which can enforce spectral constraints on the control field (and extends to arbitrary filters). The procedure differs from standard algorithms in that at each iteration the control field is taken as a linear combination of the control field (computed by the standard algorithm) and the filtered field. The parameter of the linear combination is chosen to respect the monotonic behavior of the algorithm and to be as close to the filtered field as possible. We test the efficiency of this method on molecular alignment. Using band-pass filters, we show how to select particular rotational transitions to reach high alignment efficiency. We also con…

Light-scattering spectra of supercooled molecular liquids

2001

The light scattering spectra of molecular liquids are derived within a generalized hydrodynamics. The wave vector and scattering angle dependences are given in the most general case and the change of the spectral features from liquid to solidlike is discussed without phenomenological model assumptions for (general) dielectric systems without long-ranged order. Exact microscopic expressions are derived for the frequency-dependent transport kernels, generalized thermodynamic derivatives and the background spectra.

Discrete-valued-pulse optimal control algorithms: Application to spin systems

2015

International audience; This article is aimed at extending the framework of optimal control techniques to the situation where the control field values are restricted to a finite set. We propose generalizations of the standard GRAPE algorithm suited to this constraint. We test the validity and the efficiency of this approach for the inversion of an inhomogeneous ensemble of spin systems with different offset frequencies. It is shown that a remarkable efficiency can be achieved even for a very limited number of discrete values. Some applications in nuclear magnetic resonance are discussed.

ADVANCED STATISTICAL ANALYSIS OF LOCAL BUBBLE SIZE DISTRIBUTIONS IN 2D GAS FLUIDIZED BEDS

2009

The principal difficulty in analysing fluidization quality and bubble dynamics is related to the possibility of measuring or predicting the physical and geometrical properties of gas bubbles rising in a granular medium. Even the development of detailed experimental correlations gives poor results, being necessary a fully statistical approach. On the above basis, the present work focuses on the statistical analysis of the behaviour of a 2-D fluidized bed operating under bubbling and slugging conditions, performing measurements of Local Bubble Size Distributions (BSD) along the bed. The analysis allowed to observe a characteristic bimodal shape of BSDs for different particles dimension and fl…

"Table 2" of "A Precise Determination of the Number of Families With Light Neutrinos and of the $Z$ Boson Partial Widths"

1990

Calorimeter selection.

La sensación sonora y visual del mar en la pintura valenciana de finales del siglo XIX

2010

This work presents an interpretation from a phenomenological point of view of the visual and sonorous experience on the perception of the sea in the context of XIX century Valencian painting. The use of senses to generate images of the sea establishes a network of links between them that plays a key role in the comprehension and interpretation of its image. The analysis starts from the identification of an autonomous and separated poetics of the sea, focusing on the study of its immensity from the different points of view that its contemplation presents. It ends on the interpretation of the sonorous and mobile potentiality of its matter. The study has identified in the chosen images of the …

Añadiduras a la relacion verìdica : que sobre las fiestas de Valencia, por la proclamacion de nuestro Rey el Señor Don Carlos III ... escribiò Joseph…

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Justos fundados elogios, que por su singular desempeño en la construccion de Altar, para la feliz proclamacion de nuestro catholico monarca el Señor …

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