Persistence of the valence bond glass state in the double perovskites Ba2-xSrxYMoO6

Peer reviewedPublisher PD

Passivity-based harmonic control through series/parallel damping of an H-bridge rectifier

Nowadays the H-bridge is one of the preferred solutions to connect DC loads or distributed sources to the single-phase grid. The control aims are: sinusoidal grid current with unity power factor and optimal DC voltage regulation capability. These objectives should be satisfied, regardless the conditions of the grid, the DC load/source and the converter nonlinearities. In this paper a passivity-based approach is thoroughly investigated proposing a damping-based solution for the error dynamics. Practical experiments with a real converter validate the analysis.

Clustering and light profiles of galaxies in the environment of 20 Ultra Steep Spectrum Radio sources

We have analyzed galaxy properties in the neighborhood of 20 Ultra-Steep Spectrum Radio sources (USS) taken from the WISH catalog of De Breuck et al. (2002). Galaxies in these USS fields were identified in deep observations that were carried out in the K'-band using the OSIRIS imager at the CTIO 4m telescope. We find a statistically significant signal of clustering around our sample of USS. The angular extension of the detected USS-galaxy clustering is theta_c~20" corresponding to a spatial scale ~120 h^{-1}kpc, assuming the sources are at z~1 in a Omega_m=0.3, Omega_{\Lambda}=0.7 model universe. These results are in agreement with those obtained by Best (2000) for radio galaxy-galaxy correlation, and Best et al. (2003) for radio-loud AGN-galaxy correlation. We have also analyzed the light distribution of the galaxies by fitting Sersic's law profiles. Our results show no significant dependence of the galaxy shape parameters on the projected distance to the USS.Comment: Accepted for its publication in Astronomical Journal, 9 figure

Valence bond glass on an fcc lattice in the double perovskite Ba2YMoO6

Peer reviewedPublisher PD

Deuteron Magnetic Quadrupole Moment From Chiral Effective Field Theory

We calculate the magnetic quadrupole moment (MQM) of the deuteron at leading order in the systematic expansion provided by chiral effective field theory. We take into account parity and time-reversal violation which, at the quark-gluon level, results from the QCD vacuum angle and dimension-six operators that originate from physics beyond the Standard Model. We show that the deuteron MQM can be expressed in terms of five low-energy constants that appear in the parity- and time-reversal-violating nuclear potential and electromagnetic current, four of which also contribute to the electric dipole moments of light nuclei. We conclude that the deuteron MQM has an enhanced sensitivity to the QCD vacuum angle and that its measurement would be complementary to the proposed measurements of light-nuclear EDMs

Why High-Speed Railway stations continue China's leapfrog urbanization: institutional parameters of urban development

An ambitious program of High-Speed Railway (HSR) is under construction in China and already soon the network will overtake its counterparts in Europe. Reflecting on experiences in Europe, the authors explore the conditions for place making qualities of six new HSR station areas in China. The superb inter-city connectivity of the new infrastructure nodes raises a lot of expectations about the economic and social potential of the station areas, but the experiences in Europe thus far are very differentiated. With regards to the attraction of economic activities usually the existing differences between different economic regions are reproduced rather than shaping completely new conditions. Also the expectations of developing completely new integrated urban centers around stations in the urban periphery are rather ambitious. The paper questions the planning responses to HSR development in Chinese cities and investigates the institutional conditions that frame these responses. The authors explore how the plans for Chinese HSR station development account for their objectives and reflect on the potential of the station area planning by investigating the institutional parameters of urban development

Chiral separation by enantioselective liquid–liquid extraction

The literature on enantioselective liquid–liquid extraction (ELLE) spans more than half a century of research. Nonetheless, a comprehensive overview has not appeared during the past few decades. Enantioselective liquid–liquid extraction is a technology of interest for a wide range of chemists and chemical engineers in the fields of fine chemicals, pharmaceuticals, agrochemicals, fragrances and foods. In this review the principles and advances of resolution through enantioselective liquid–liquid extraction are discussed, starting with an introduction on the principles of enantioselective liquid–liquid extraction including host–guest chemistry, extraction and phase transfer mechanisms, and multistage liquid–liquid extraction processing. Then the literature on enantioselective liquid–liquid extraction systems is reviewed, structured on extractant classes. The following extractant classes are considered: crown ether based extractants, metal complexes and metalloids, extractants based on tartrates, and a final section with all other types of chiral extractants.

Unraveling models of CP violation through electric dipole moments of light nuclei

We show that the proposed measurements of the electric dipole moments of light nuclei in storage rings would put strong constraints on models of flavor-diagonal CP violation. Our analysis is exemplified by a comparison of the Standard Model including the QCD theta term, the minimal left-right symmetric model, a specific version of the so-called aligned two-Higgs doublet model, and briefly the minimal supersymmetric extension of the Standard Model. By using effective field theory techniques we demonstrate to what extend measurements of the electric dipole moments of the nucleons, the deuteron, and helion could discriminate between these scenarios. We discuss how measurements of electric dipole moments of other systems relate to the light-nuclear measurements.Comment: Published versio