4,221 research outputs found

    De zorg ontketend? in ketens?:Afscheidsrede van Dr. P. Pop

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    New rr-Matrices for Lie Bialgebra Structures over Polynomials

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    For a finite dimensional simple complex Lie algebra g\mathfrak{g}, Lie bialgebra structures on g[[u]]\mathfrak{g}[[u]] and g[u]\mathfrak{g}[u] were classified by Montaner, Stolin and Zelmanov. In our paper, we provide an explicit algorithm to produce rr-matrices which correspond to Lie bialgebra structures over polynomials

    THE EVOLUTION OF AGRICULTURAL SURFACES, BY USE CATEGORIES, IN THE SW AND NW REGIONS OF ROMANIA

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    The paper analyzes the evolution after 1990 of the areas occupied by categories of agricultural use, in the NW and SW development regions of Romania. The areas occupied by agricultural land had similar evolutions, with some small exceptions, due primarily to the predominant landforms in the two analyzed development regions. The data are incomplete, waiting for the conclusion of the National Cadastre and Land Book Program 2015-2023

    Classification of quantum groups and Belavin--Drinfeld cohomologies for orthogonal and symplectic Lie algebras

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    In this paper we continue to study Belavin-Drinfeld cohomology introduced in arXiv:1303.4046 [math.QA] and related to the classification of quantum groups whose quasi-classical limit is a given simple complex Lie algebra. Here we compute Belavin-Drinfeld cohomology for all non-skewsymmetric rr-matrices from the Belavin-Drinfeld list for simple Lie algebras of type BB, CC, and DD.Comment: 17 page

    Avalanche-Induced Current Enhancement in Semiconducting Carbon Nanotubes

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    Semiconducting carbon nanotubes under high electric field stress (~10 V/um) display a striking, exponential current increase due to avalanche generation of free electrons and holes. Unlike in other materials, the avalanche process in such 1D quantum wires involves access to the third sub-band, is insensitive to temperature, but strongly dependent on diameter ~exp(-1/d^2). Comparison with a theoretical model yields a novel approach to obtain the inelastic optical phonon emission length, L_OP,ems ~ 15d nm. The combined results underscore the importance of multi-band transport in 1D molecular wires

    Charge transfer complexes and radical cation salts of chiral methylated organosulfur donors

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    The single crystal X-ray structure of the all-axial conformer of the (R,R,R,R) enantiomer of the chiral donor tetramethyl-BEDT-TTF (TM-BEDT-TTF) was described and compared to the all-equatorial conformer. (S,S,S,S)-Tetramethyl-BEDT-TTF formed crystalline 1 : 1 complexes with TCNQ and TCNQ-F4, as well as a THF solvate of the TCNQ complex. Donors bis((2S,4S)-pentane-2,4-dithio)tetrathiafulvalene and (ethylenedithio)((2S,4S)-pentane-2,4-dithio)tetrathiafulvalene, which contain seven-membered rings bearing chirally oriented methyl groups, only formed complexes with TCNQ-F4. The TCNQ-F4 complexes contain planar organosulfur systems, in contrast to the TCNQ complexes in which there is minimal charge transfer. A variety of crystal packing modes were observed. Electrocrystallization experiments with both enantiomers and the racemic form of tetramethyl-BEDT-TTF afforded mixed valence radical cation salts with the AsF6 and SbF6 anions formulated as (TM-BEDT-TTF)2XF6 (X = As, Sb). Electrical conductivity was only found in one charge transfer complex, while the radical cation salts are all semiconducting
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