303 research outputs found

    Optical Absorption and Raman Spectroscopy Study of the Fluorinated Double-Wall Carbon Nanotubes

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    Double-wall carbon nanotube (DWNT) samples have been fluorinated at room temperature with varied concentration of a fluorinating agent BrF3. Content of the products estimated from X-ray photoelectron data was equal to CF0.20 and CF0.29 in the case of deficit and excess of BrF3. Raman spectroscopy showed considerable decrease of carbon nanotube amount in the fluorinated samples. Analysis of optical absorption spectra measured for pristine and fluorinated DWNT samples revealed a selectivity of carbon nanotube fluorination. Nanotubes with large chiral angle are more inert to the fluorinating agent used

    Redescriptions of Ligophorus cephali Rubtsova, Balbuena, Sarabeev, Blasco-Costa & Euzet, 2006 and L. chabaudi Euzet & Suriano, 1977 (Monogenea: Ancyrocephalidae), with notes on the functional morphology of the copulatory organ

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    Redescriptions of Ligophorus cephali Rubtsova, Balbuena, Sarabeev, Blasco-Costa & Euzet, 2006 and L. chabaudi Euzet & Suriano, 1977 based on original material from the Black Sea, the Mediterranean Sea and the Sea of Japan are presented. A comparison of samples of these two species from different regions was carried out with the aid of principal components analysis. The occurrence of L. chabaudi on Mugil cephalus in the Sea of Japan was confirmed. The functional morphology of the male copulatory organ was examined, and the use of the shape of this structure in the taxonomy of Ligophorus Euzet & Suriano, 1977 is discussed

    Redescription of Ligophorus mediterraneus Sarabeev, Balbuena & Euzet, 2005 (Monogenea: Ancyrocephalidae) with some methodological notes

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    A redescription of Ligophorus mediterraneus Sarabeev, Balbuena & Euzet, 2005, based on original material from the Black and Mediterranean Seas, is presented and new diagnostic characters for its recognition are proposed. The unlikely wide range of variation in the angle between the shaft and point of the anchors, reported for this species and for some others in the genus, is analysed, and the structure of the ventral bar in Ligophorus spp. is described and its taxonomic significance discussed

    The Study of the Conformation and Dynamics of the New Quaternary Phosphonium Salts by NMR Spectroscopy

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    A number of quaternary phosphonium salts on the basis of pyridoxine derivatives were investigated by nuclear magnetic resonance (NMR) spectroscopy methods. Conformational exchange processes for each compound in solution were studied using dynamic NMR experiments. Energy barriers of the conformational transitions were determined. © 2014 Springer-Verlag Wien

    Algorithm and performance of a clinical IMRT beam-angle optimization system

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    This paper describes the algorithm and examines the performance of an IMRT beam-angle optimization (BAO) system. In this algorithm successive sets of beam angles are selected from a set of predefined directions using a fast simulated annealing (FSA) algorithm. An IMRT beam-profile optimization is performed on each generated set of beams. The IMRT optimization is accelerated by using a fast dose calculation method that utilizes a precomputed dose kernel. A compact kernel is constructed for each of the predefined beams prior to starting the FSA algorithm. The IMRT optimizations during the BAO are then performed using these kernels in a fast dose calculation engine. This technique allows the IMRT optimization to be performed more than two orders of magnitude faster than a similar optimization that uses a convolution dose calculation engine.Comment: Final version that appeared in Phys. Med. Biol. 48 (2003) 3191-3212. Original EPS figures have been converted to PNG files due to size limi

    Dependent coordinates in path integral measure factorization

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    The transformation of the path integral measure under the reduction procedure in the dynamical systems with a symmetry is considered. The investigation is carried out in the case of the Wiener--type path integrals that are used for description of the diffusion on a smooth compact Riemannian manifold with the given free isometric action of the compact semisimple unimodular Lie group. The transformation of the path integral, which factorizes the path integral measure, is based on the application of the optimal nonlinear filtering equation from the stochastic theory. The integral relation between the kernels of the original and reduced semigroup are obtained.Comment: LaTeX2e, 28 page
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