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Summary The silica-supported comb-shaped polymer (Sil-ODA18) with a “crystalline-to-isotropic” phase transition showed the characteristic behaviors of both polymeric and monomeric ODS
phases. This was examined using a SRM 869 test mixture. Furthermore, Sil-ODA18 exhibited a specific selectivity towards the critical pairs of polycyclic aromatic hydrocarbons (PAHs), such as acenaphthene
and fluorene, or benz(a)anthracene and chrysene, or benzo(ghi)perylene, indeno(1,2,3-cd)pyrene and dibenz(a,h)anthracene.
The separation of these solutes was controlled by selecting temperature and solvent systems. The selectivity on Sil-ODA18 was also compared with a conventional ODS (octadecylsilyl silica gel) column. The selectivity on a Sil-ODA18 matrix is attributable to an orientation change of the long-chain alkyl substituents on the surface of the silica base material
on transition from crystalline to isotropic state. 相似文献
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We have considered a cosmological model of the FRW universe with variable G and Λ. The solutions have been obtained for flat model with particular form of cosmological constant. The cosmological parameters
have also been obtained for dust, radiation and stiff matter. The statefinder parameters are analyzed and have shown that
these depends only on w and ε. Further the lookback time, proper distance, luminosity distance and angular diameter distance have also been calculated
for our model. 相似文献
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Electromembrane extraction (EME) was carried out using a novel instrumentation capable of impedometric monitoring of the system during the extraction. This instrumentation involves a classical two-electrode assembly fed by two time-resolved potential functions, the first for the extraction of analyte and the second for obtaining the impedance information. The impedometric analysis of the system was achieved by Laplace transformation of the current recorded during the extraction. It has been shown that the obtained impedance information can be converted to very useful knowledge about time dependence of double layer capacitance, kinetics of analyte depletion, total permeability of the SLM and the effect of experimental parameters on system behavior. It has also been shown that the impedance analysis is a powerful tool for the estimation of optimum experimental parameters without determination of analyte in the acceptor phase. 相似文献
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