26 research outputs found

    Erratum: Measurement of the t(t)over-bar production cross section in the dilepton channel in pp collisions at root s = 8 TeV (vol 2, 024, 2014)

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    SOME PROBLEMS OF CREATING ELECTRIC ENVIRONMENTALLY FRIENDLY AIRCRAFT

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    In the article the questions connected with the possibility of creating environmentally friendly electric aircraft are considered. It is suggested to use modern accumulators based on the lithium-thionyl chloride as a source of electrical energy

    Conformational Dynamics of Surfactant in a Mesolamellar Composite Studied by Local Field NMR Spectroscopy

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    Ordered mesostructured materials possess unique surface, structural, and bulk properties that lead to important practical applications. Mesostructured organic–inorganic composites are also of broad interest for fundamental studies of confinement effects and surface interaction on structural and dynamic properties of organic molecules. In the present study, solid state dipolar <sup>13</sup>C–<sup>1</sup>H NMR spectroscopy is applied to quantitatively characterize the conformational dynamics of a surfactant in a mesolamellar composite. By applying dipolar recoupling and separated local field spectroscopy techniques, the motion of surfactant molecules was studied in a wide range of mobilities from an essentially immobilized rigid state to a highly flexible and anistropically tumbling state. From the analysis of the measured heteronuclear dipolar couplings, the orientational order parameters of C–H bonds along the surfactant chain were determined. The study shows that in surfactant bilayers in AlPO layered structure at room temperature the highly ordered chains in all-trans conformation undergo fast rotation about the molecular axis. In a higher temperature phase, the order parameter is gradually decreasing toward the chain end due to conformational transitions; however, the dynamics of the segment in the vicinity of the headgroup is only slightly affected. The conformational dynamics in the surfactant bilayers confined between solid inorganic sheets is also compared to that in fluid bilayers in an aqueous lamellar phase

    Molecular and Segmental Orientational Order in a Smectic Mesophase of a Thermotropic Ionic Liquid Crystal

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    We investigate conformational dynamics in the smectic A phase formed by the mesogenic ionic liquid 1-tetradecyl-3-methylimidazolium nitrate. Solid-state high-resolution 13C nuclear magnetic resonance (NMR) spectra are recorded in the sample with the mesophase director aligned in the magnetic field of the NMR spectrometer. The applied NMR method, proton encoded local field spectroscopy, delivers heteronuclear dipolar couplings of each 13C spin to its 1H neighbours. From the analysis of the dipolar couplings, orientational order parameters of the C&ndash;H bonds along the hydrocarbon chain were determined. The estimated value of the molecular order parameter S is significantly lower compared to that in smectic phases of conventional non-ionic liquid crystals
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