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61.
62.
The simulations of emeraldine hydrochloride tetramers were performed for the first time in implicit water solvent using the polarisable continuum model (PCM) with the density functional theory (DFT) method. This approach should be more appropriate for the study of the conducting form of polyaniline as all known processes of synthesis and further transformations take place in polar medium. Our results confirm this hypothesis and clearly indicate that the geometry and electronic structure of the emeraldine salt depend on the dielectric properties of the medium. In polar environment the protons are bound tighter to the chains compared to vacuum and this leads to stronger impact of the dopant on the structural parameters of PANI. As a consequence, the density distribution in the emeraldine hydrochloride obtained by PCM is more realistic compared to vacuum estimates. The stability in polar medium of two possible salt configurations with respect to counterions position is assessed. Each configuration is simulated in singlet and triplet state (bipolaron and polaron). The results show that at the tetramer level the bipolaron form is always preferred in accordance to available experimental results. 相似文献
63.
Triboengineering tests of composites based on blends of fluoroplastics modified with magnesium nanospinel demonstrate the
regularities of the appearance of friction surfaces on these metal-polymer pairs. The new materials are characterized by low
and stable friction coefficients and wear rates and improved resistance to deformation, considerably expanding the range of
their application in sealing systems and friction units. 相似文献
64.
Boris A. Trofimov Marina V. Markova Inna V. Tatarinova Al’bina I. Mikhaleva Lyudmila V. Morozova Ol’ga V. Petrova Lyubov’ N. Sobenina Konstantin B. Petrushenko Tamara I. Vakul'skaya Spartak S. Khutsishvili Galina F. Prozorova 《Synthetic Metals》2010,160(23-24):2573-2580
I2-doped and pyrrole ring-iodinated semi-conducting oligomers of N-vinyl-3-alkyl-2-phenylpyrroles have been synthesized by free-radical polymerization of the above monomers (AIBN, 2–5 wt%, 60–80 °C) and further exposure of the oligomers obtained to I2 vapor. The parent oligomers exhibit paramagnetic and fluorescent properties and stable up to 300–370 °C. 相似文献
65.
EE Miniat EB Khomiakova MV Petrova MZ Gorgoshidze VI Ivanov 《Canadian Metallurgical Quarterly》1998,32(6):1013-1019
A HPLC method was developed and validated for the quantitation of 9-cis-retinoic acid (ALRT1057) and its major metabolite, 4-oxo-9-cis-retinoic acid (LG100182) in human plasma. Samples were buffered and extracted with methyl-tert-butyl-ether. The analytes and an I.S. were separated on a C18 HPLC column using a shallow gradient of 70-89% organic solvent. The analytes were quantitated by UV detection at 348 nm. Selectivity against endogenous compounds and potential metabolites (retinol, all trans-, 13-cis-, and 4-hydroxy-9-cis-retinoic acid) was demonstrated. The run time was 29 min. The standard curve was linear from 2.5 to 450 ng ml-1. Interassay precision for both analytes in quality control samples was less than 5.0% RSD. Accuracy was within 11.0% RE for both compounds. Analyte stability during sample storage, extraction processing, and chromatography was established. Method ruggedness was tested by two analysts and on two HPLC systems. This method has been applied to the quantitation of clinical samples. 相似文献
66.
O. A. Potapov N. A. Andreev I. B. Murashova A. V. Pomosov V. N. Kozhanov T. A. Petrova 《Powder Metallurgy and Metal Ceramics》1990,29(2):91-96
Translated from Poroshkovaya Metallurgiya, No. 2(326), pp. 1–8, February, 1990. 相似文献
67.
Study of p-type porous silicon has been carried out by x-ray reflectometry for the first time. Its critical total-external-reflection
angle and its reflection coefficient in the subcritical angle range are much smaller than for c-Si, which was grown by the Czochralski method. The critical angle decreases with increase of the porosity. The critical angle
and the reflection coefficient increase with aging. These results are attributable to the much smaller electron density of
porous silicon in comparison with c-Si, to the microgeometry of its surface, and to changes in both of these factors attendant to aging due to an increase in
the concentration of atmospheric constituents observed in the infrared absorption spectra. As the porosity increases, the
concentration of atmosmopheric impurities also increases, and in high-porosity material in addition to chemically adsorbed
oxygen, carbon and water seem to contribute appreciably.
Fiz. Tekh. Poluprovodn. 31, 957–960 (August 1997) 相似文献
68.
A method for the hermetic connection of small-diameter high-pressure tubing to a high-pressure apparatus without soldering is described. 相似文献
69.
V. A. Lashkov A. V. Petrova R. G. Safin 《Journal of Engineering Physics and Thermophysics》2002,75(5):1048-1053
A mathematical model for the process of self-freezing of moist materials in a continuously increasing vacuum which is developed on the basis of the approximate solutions obtained by A. V. Luikov for drying of capillary-porous media is presented. Results of experimental investigations into the self-freezing of a moist cloth are given, from which the temperature of supercooling of the surface material layer, the temperature coefficient, and the velocity of deepening of the freezing surface are determined; all of these parameters are used in mathematical simulation of the above process. 相似文献