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31.
Kumar R Ling W Schoefberger W Jerschow A 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2005,172(2):209-213
We describe an NMR experiment that produces spectra correlating the first-order quadrupolar spectrum and the central transition spectrum of half-integer quadrupolar spins, allowing one to separate the quadrupolar parameters in overlapping spectra under both static and magic-angle-spinning conditions. Promising fields of applications include situations where the sample cannot easily be rotated, or where it cannot be rotated at the magic angle. 相似文献
32.
Alexej Nikiforov Leopold Jirovetz Gerhard Buchbauer 《Monatshefte für Chemie / Chemical Monthly》1986,117(6-7):827-839
The most odour intensive constituents of east indian sandal wood oil are -santalol, -santalal and -santalene. This has been proved by a thorough GLC-investigation in combination with the sniffing technique of seven fractions of this highly priced essential oil, which have been obtained by TLC on silica-cellulose plates with simultaneous organoleptic evaluation. Using the headspace analysis these results could be confirmed and further the distribution of the main odour components was obtained in headspace at 37° and 80°.
Herrn Prof. DDr. h. c.K. Kratzl in dankbarer Verehrung mit den besten Wünschen zum 70. Geburtstag gewidmet. 相似文献
33.
Alexej Pogorelov Lennart Schneiders Matthias Meinke Wolfgang Schröder 《Flow, Turbulence and Combustion》2018,100(1):19-38
An efficient Cartesian cut-cell/level-set method based on a multiple grid approach to simulate turbulent turbomachinery flows is presented. The finite-volume approach in an unstructured hierarchical Cartesian setup with a sharp representation of the complex moving boundaries embedded into the computational domain, which are described by multiple level-sets, ensures a strict conservation of mass, momentum, and energy. Furthermore, an efficient kinematic motion level-set interface method for the rotation of embedded boundaries described by multiple level-set fields on a computational domain distributed over several processors is introduced. This method allows the simulation of multiple boundaries rotating relatively to each other in a fixed frame of reference. To demonstrate the efficiency of the numerical method and the quality of the computed findings the generic test problem of a rotating cylinder surrounded by a stationary hull and the flow over a ducted rotating axial fan with a stationary turbulence generating grid at the inflow are simulated. The computational results of the axial fan show a good agreement with the experimental data. 相似文献
34.
35.
Advanced composite materials aimed for construction of organic photovoltaic cells have been studied by atomic force microscopy (AFM). The composites are based on poly(3-hexylthiophene) (P3HT), [6,6]-phenyl C61-butyric acid methyl ester (PCBM) and two different chiral photosensitive liquid crystalline (LC) materials. The objective of the study was to examine the nanoscale morphology of the active layer without and after annealing at specific temperature. The preliminary results of AFM observation of the morphological changes done on the investigated composites revealed an increase in the surface ordering. The surface area ratio decreases for both studied composites, while the basic roughness parameters (Sa and Sq) have been found toughly dependent on the structure of the photosensitive LC dopant. 相似文献
36.
Alexej Jerschow 《Monatshefte für Chemie / Chemical Monthly》2002,133(12):1481-1496
Summary. Most NMR-active nuclei found in the periodic table have a quadrupole moment. In combination with a nonsymmetric electron
distribution a strong NMR-active interaction results, which very often overshadows the dipolar and scalar couplings. This
article aims at reviewing how these interactions manifest themselves in quadrupolar NMR and how they can be exploited for
resonance assignment and structure elucidation, in spite of the presence of a strong quadrupolar interaction.
E-mail: alexej.jerschow@nyu.edu
Received April 16, 2002; accepted May 15, 2002 相似文献
37.
Jakub Fitas Katarzyna Kurp Magdalena Żurowska Marzena Tykarska Alexej Bubnov 《Liquid crystals》2017,44(9):1468-1476
Several new binary liquid crystalline mixtures have been designed and their properties were studied by complementary methods. It has been shown that even both pure components used for the mixture design possess the ferroelectric behaviour; the induced antiferroelectric smectic phase has been detected for one of the prepared mixtures. The phase diagram has been constructed and the existence of the antiferroelectric phase was confirmed by switching time and dielectric spectroscopy measurements. Some of the resulted mixtures possess very high values of the tilt angle that reaches close below 45° degrees at saturation. Values of spontaneous polarisation were found within 50–200 nC/cm2 in dependence of the mixture’s composition. Due to specific properties, the obtained mixtures might be interesting for further design of multicomponent mixtures and formulation of the advanced nanocomposite systems. 相似文献
38.
Several types of the chiral thiols with two aromatic rings have been synthesised and grafted on polybutadiene diols backbone. The resulting functional polymers possess the OH end groups for the possible preparation of liquid crystal ordered networks. The thermal and mesomorphic properties of the synthesised side-chain units and resulting polymers have been studied by polarising optical microscopy, differential scanning calorimetry and X-ray scattering. Some of the resulting polymers possess a mesomorphic behaviour. The effects of the side-chain structure, number of the chiral groups and density of grafting on the polybutadiene diols have been studied. 相似文献
39.
Mixtures of cold bosonic atoms in optical lattices undergo demixing on different length scales with increasing interspecies repulsion. As a general rule, the stronger the intraspecies interactions, the shorter is this length scale. The wealth of phenomena is documented by illustrative examples on both superfluids and Mott insulators. 相似文献
40.
Rong P Regatte RR Jerschow A 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2008,193(2):207-209
Monitoring the sodium concentration in vivo using 23Na MRI can be an important tool for assessing the onset of tissue disorders. Practical clinical 23Na MRI methods furthermore often do not allow one to use sufficiently small voxel sizes such that only the tissue of interest is seen, but a large signal contamination can arise from sodium in synovial fluid. Here we demonstrate that applying an inversion recovery (IR) technique allows one to distinctly select either the cartilage-bound or the free sodium for visualization in an image. The results are validated both ex vivo and in vivo. 相似文献