2,859 research outputs found

    Una introducción a la traducción científica

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    Sección: Reseñas bibliográficas. Http://www.medtrad.orgEsta obra del traductor y profesor francés Jean Maillot (1905-1993) no es un tratado teórico de traducción ni un manual de metodología de la traducción, sino una exposición sencilla y clara de algunos de los problemas de la traducción científica y técnica a través de una abundante acumulación de casos concretos extraídos del francés, alemán, inglés y ruso.Peer reviewe

    Evidence of secondary relaxations in the dielectric spectra of ionic liquids

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    We investigated the dynamics of a series of room temperature ionic liquids based on the same 1-butyl-3-methyl imidazolium cation and different anions by means of broadband dielectric spectroscopy covering 15 decades in frequency (10^(-6)-10^9 Hz), and in the temperature range from 400 K down to 35 K. An ionic conductivity is observed above the glass transition temperature T_{g} with a relaxation in the electric modulus representation. Below T_{g}, two relaxation processes appear, with the same features as the secondary relaxations typically observed in molecular glasses. The activation energy of the secondary processes and their dependence on the anion are different. The slower process shows the characteristics of an intrinsic Johari-Goldstein relaxation, in particular an activation energy E_{beta}=24k_{B}T_{g} is found, as observed in molecular glasses.Comment: Major revision, submitted to Phys. Rev. Let

    Extraordinarily Efficient Conduction in a Redox-Active Ionic Liquid

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    Iodine added to iodide-based ionic liquids leads to extraordinarily efficient charge transport, vastly exceeding that expected for such viscous systems. Using terahertz time-domain spectroscopy, in conjunction with dc conductivity, diffusivity and viscosity measurements we unravel the conductivity pathways in 1-methyl-3-propylimidazolium iodide melts. This study presents evidence of the Grotthuss mechanism as a significant contributor to the conductivity, and provides new insights into ion pairing processes as well as the formation of polyiodides. The terahertz and transport results are reunited in a model providing a quantitative description of the conduction by physical diffusion and the Grotthuss bond-exchange process. These novel results are important for the fundamental understanding of conduction in molten salts and for applications where ionic liquids are used as charge-transporting media such as in batteries and dye-sensitized solar cells.Comment: Article: 17 pages, 3 figures. Supplementary information: 14 pages, 6 figures. Table of contents figure: 1 page. Accepted for publication in ChemPhysChe
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