The role of language skills in interactive social book search sessions

When searching for books, people frequently have to deal with content that is in a language different from their own. However, research on multilingual systems has generally focused on the user interface's language rather than the content language. In this paper, we describe and compare early results from the multilingual aspects in the Interactive Social Book Search (iSBS) task at CLEF 2014 and 2015. A preliminary analysis of usage patterns for native English and non-native English speakers indicates an influence of language skills on search behaviour during goal-oriented and casual leisure tasks. Based on previous experiences and results, strengths and challenges of IIR studies are discussed

ARPES: A probe of electronic correlations

Angle-resolved photoemission spectroscopy (ARPES) is one of the most direct methods of studying the electronic structure of solids. By measuring the kinetic energy and angular distribution of the electrons photoemitted from a sample illuminated with sufficiently high-energy radiation, one can gain information on both the energy and momentum of the electrons propagating inside a material. This is of vital importance in elucidating the connection between electronic, magnetic, and chemical structure of solids, in particular for those complex systems which cannot be appropriately described within the independent-particle picture. Among the various classes of complex systems, of great interest are the transition metal oxides, which have been at the center stage in condensed matter physics for the last four decades. Following a general introduction to the topic, we will lay the theoretical basis needed to understand the pivotal role of ARPES in the study of such systems. After a brief overview on the state-of-the-art capabilities of the technique, we will review some of the most interesting and relevant case studies of the novel physics revealed by ARPES in 3d-, 4d- and 5d-based oxides.Comment: Chapter to appear in "Strongly Correlated Systems: Experimental Techniques", edited by A. Avella and F. Mancini, Springer Series in Solid-State Sciences (2013). A high-resolution version can be found at: http://www.phas.ubc.ca/~quantmat/ARPES/PUBLICATIONS/Reviews/ARPES_Springer.pdf. arXiv admin note: text overlap with arXiv:cond-mat/0307085, arXiv:cond-mat/020850

THEORY AND EXPERIMENT ON THE OPTICAL-PROPERTIES OF CRSI2

The optical properties of CrSi2, both in polycrystalline and single-crystal form, were investigated between 0.01 and 5 eV. The dielectric functions were determined by different methods: Kramers-Kronig transformations of the near-normal reflectivity over the whole spectral range; direct measurement by spectroscopic ellipsometry from 1.4 to 5 eV; numerical inversion of the reflectance from two films with different thickness. The main difference between thin-film and single-crystal data is the presence, in the latter, of a strong free-carrier response, preventing the determination of the intrinsic absorption edge (interband optical gap). Moreover, the optical properties of CrSi2 were calculated within the local-density approximation using the semirelativistic linear-muffin-tin-orbital method. The band structure, the l-projected densities of states, the complex dielectric function, and the optical reflectivity were obtained in the energy range from 0 to 5 eV. The theoretical calculations are compared with the experimental data

Synergistic geometric and electronic effects for electrochemical reduction of carbon dioxide using gold–copper bimetallic nanoparticles

Highly efficient and selective electrochemical reduction of carbon dioxide represents one of the biggest scientific challenges in artificial photosynthesis, where carbon dioxide and water are converted into chemical fuels from solar energy. However, our fundamental understanding of the reaction is still limited and we do not have the capability to design an outstanding catalyst with great activity and selectivity a priori. Here we assemble uniform gold-copper bimetallic nanoparticles with different compositions into ordered monolayers, which serve as a well-defined platform to understand their fundamental catalytic activity in carbon dioxide reduction. We find that two important factors related to intermediate binding, the electronic effect and the geometric effect, dictate the activity of gold-copper bimetallic nanoparticles. These nanoparticle monolayers also show great mass activities, outperforming conventional carbon dioxide reduction catalysts. The insights gained through this study may serve as a foundation for designing better carbon dioxide electrochemical reduction catalysts