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JPC – Journal of Planar Chromatography – Modern TLC - 相似文献
74.
Physical properties of NdPd2Ge2 and NdAg2Ge2, crystallizing with the tetragonal ThCr2Si2-type crystal structure, were investigated by means of magnetic, calorimetric, electrical transport as well as by neutron diffraction measurements. The specific heat studies and neutron diffraction measurements were performed down to 0.30 K and 0.47 K, respectively. Both compounds exhibit antiferromagnetic ordering below TN equal to 1.5 K for NdPd2Ge2 and 1.8 K for NdAg2Ge2. Neutron diffraction data for the latter germanide indicate antiferromagnetic collinear structure described by the propagation vector k=(0.5, 0, 0.5). The Nd magnetic moments equal to 2.24(5) μB at 0.47 K are aligned along the a-axis and have the +− sequence within the crystal unit cell. For NdPd2Ge2 only very small Bragg peaks of magnetic origin were observed in the neutron diffraction patterns measured below TN, thus hampering determination of the magnetic structure. Both compounds exhibit metallic-like electrical conduction. From the specific heat data the crystal electric field (CEF) levels schemes were determined. Difference between the overall CEF splitting in the two compounds is correlated with their structural parameters. 相似文献
75.
Paweł K. Zarzycki Magdalena M. ŚlączkaMagdalena B. Zarzycka Elżbieta WłodarczykMichał J. Baran 《Analytica chimica acta》2012
The main goal of present paper is to demonstrate the separation and detection capability of micro-TLC technique involving simple one step liquid extraction protocols of complex materials without multi-steps sample pre-purification. In the present studies target components (cyanobacteria pigments, lipids and fullerenes) were isolated from heavy loading complex matrices including spirulina dried cells, birds’ feathers and fatty oils as well as soot samples derived from biomass fuel and fossils-fired home heating systems. In each case isocratic separation protocol involving less that 1 mL of one component or binary mixture mobile phases can be completed within time of 5–8 min. Sensitive detection of components of interest was performed via fluorescence or staining techniques using iodine or phosphomolybdic acid. Described methodology can be applied for fast fractionation or screening of whole range of target substances as well as chemo-taxonomic studies and fingerprinting of complex mixtures, which are present in raw biological or environmental samples. 相似文献
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O. V. Buganov A. D. Zamkovets A. N. Ponyavina S. A. Tikhomirov L. V. Baran 《Journal of Applied Spectroscopy》2011,78(5):686-691
Differential transient absorption spectra have been studied for planar densely packed Ag/Na3AlF6 nanostructures under ultrashort laser pulse excitation. The nanostructures were fabricated by sequential thermal evaporation
of cryolite (Na3AlF6) and silver in vacuo onto glass and quartz substrates. A nonmonotonic variation in relaxation times of induced changes in
a surface plasmon resonance band was observed with an increase in the metal surface density that resulted in nanoparticle
size growth and structural modification of the densely packed layer. The tendency of the relaxation times to vary nonmonotonically
is explained by both features of intrinsic size effects and electron-tunneling processes in plasmonic densely packed nanostructures
of various topologies. 相似文献
78.
Marta Bugaj Piotr A. Baran Piotr Bernatowicz Patrycja Brożek Krystyna Kamieńska‐Trela Adam Krówczyński Bohdan Kamieński 《Magnetic resonance in chemistry : MRC》2009,47(10):830-842
A series of aryl‐substituted enaminoketones and their thio analogues in CDCl3 solution and in the solid state were studied by the use of high‐resolution 1H and 13C as well as 13C cross polarization magic angle spinning (CP MAS) NMR spectra in combination with gauge including atomic orbitals‐density functional theory (GIAO‐DFT) calculations performed at the B3PW91/6–311 + + G(d,p) level of theory using the B3PW91/6‐311 + + G(d,p)‐optimized geometries. The analysis of the 13C NMR spectra in solution was done by using the Incredible Natural Abundance DoublE QUAntum Transfer Experiment (INADEQUATE) technique, whereas trends observed in the 13C shielding constants, calculated for the compounds studied, were a great help in assigning most of the signals in the 13C CP MAS NMR spectra. It was established on the basis of the experimental and theoretical NMR data that both groups of compounds exist in the form of Z‐s‐Z‐s‐E isomers in CDCl3 solution as well as in the solid state, with the NH hydrogen atom involved in intramolecular hydrogen bonding. This conclusion is in agreement with the fact that some of the compounds studied reveal liquid‐crystalline properties. Three‐bond H, H and C, H coupling constants measured in solution played a crucial role in the structure elucidation. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
79.
M. Baran 《Acta Mathematica Hungarica》1998,80(3):211-224
In this paper, various generalizations of the usual completely regular spaces and completely normal spaces to topological categories are given. Moreover, the relationships among various forms of these generalizations are investigated. 相似文献
80.