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1.
2.
Semen Koksal 《Applicable analysis》2013,92(1-2):99-107
In this paper, without assuming the conditions everywhere, we study nonuniform stability properties of differential systems by employing the method of perturbing Lyapunov functions and splitting the given system suitably 相似文献
3.
Mikhail Kamencev Nina Yakimova Leonid Moskvin Irina Kuchumova Kirill Tkach Yulia Malinina Oleg Tungusov 《Electrophoresis》2015,36(24):3014-3017
Separation of 6Li and 7Li isotopes by CZE was demonstrated. The BGE contained 5 mM 4‐aminopyridine, 0.9 mM oxalic acid, 0.25 mM CTAB, and 0.25% w/v Tween 20 (рН = 9.2). The running conditions were +25 kV at 30°C with indirect photometric detection at 261 nm. Under optimal experimental conditions, the analysis time was less than 21 min. Separation of Li preparations with mole fraction of 6Li ranging from 3.44 up to 90.38% was demonstrated. 相似文献
4.
5.
Sergey V. Ryabukhin Andrey S. Plaskon Semen S. Bondarenko Oleksandr O. Grygorenko Oleg V. Shishkin 《Tetrahedron letters》2010,51(32):4229-812
Chlorotrimethylsilane-promoted Biginelli-type reaction of ethyl 2,4-dioxo-4-phenylbutanoate, benzaldehyde, and various (thio)ureas is explored. The outcome of the reaction depends on the structure of the (thio)urea used and is strongly affected by the acceptor electronic properties of the COOEt substituent in the molecule of the starting β-dicarbonyl compound. The di- and tetrahydropyrimidine derivatives obtained possess two functional groups with orthogonal reactivity, and thus represent promising building blocks for drug discovery. 相似文献
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7.
Semen B. Kharchenko Rangaramanujam M. Kannan Jeff J. Cernohous Shivshankar Venkataramani Gaddam N. Babu 《Journal of Polymer Science.Polymer Physics》2001,39(21):2562-2571
With the increase in sophisticated synthesis methods, it appears that polymer architecture may be a tunable property. Therefore, the role of architecture in rheological and processing properties has received renewed attention, mainly because of dendrimer synthesis and metallocene‐catalyst technology. Linear polymers and hyperbranched polymers represent two ends of branching complexity. Some previous studies have suggested that hyperbranched polymers may behave like unentangled polymers, whereas others have proposed that they exhibit the properties of soft colloids. In an effort to compare the responses of linear and hyperbranched polymers, we synthesized starlike hyperbranched polystyrenes (HBPSs) of various branch lengths and numbers of branches. The HBPSs used in this study were unentangled or weakly entangled, allowing us to study the effect of branch density more readily. Two linear polystyrene (L‐PS) melts and two HBPSs were studied. Using a custom‐built rheooptical apparatus, we characterized the rheology and flow birefringence of these materials. To our knowledge, these are the first flow birefringence measurements on highly branched polymer melts. Our results suggest that the flow behavior of HBPS is significantly different from that of L‐PS: (1) HBPS shows nonterminal behavior in the low‐frequency rheological response; (2) when the stress‐optical rule (SOR) holds, the stress‐optical coefficient of HBPS is much lower than those of analogous linear polymers; and (3) when the branch density is high and the branch length is sufficiently low, the SOR fails for these homopolymer melts. A significant increase in the birefringence for a given amount of stress in the low‐frequency region suggests that there may be a soft core in these materials due to the strong preferential radial orientation of chain segments near the center of a molecule versus those near the periphery. The predominantly elastic response of the soft structures may be responsible for the enhanced form birefringence. Our preliminary results indicate that these materials may exhibit both polymeric and soft‐colloid natures. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2562–2571, 2001 相似文献
8.
A. V. Bulatov U. M. Strashnova A. B. Vishnikin G. M. Alekseeva T. D. Sineva A. L. Moskvin L. N. Moskvin 《Journal of Analytical Chemistry》2011,66(3):275-279
A procedure is developed for the photometric determination of ascorbic acid in drug preparations. It is based on the rapid
and highly selective reaction of ascorbic acid with a novel reagent, the guanidinium salt of 1-bismuto-11-molybdophosphoric
heteropolyacid. The detection limit for ascorbic acid in stepwise injection analysis makes 15 mg/L, and the duration of single
analysis, 5 min. 相似文献
9.
A. V. Bulatov P. A. Ivasenko K. A. Subbotina A. B. Vishnikin L. N. Moskvin 《Journal of Analytical Chemistry》2010,65(3):234-238
A procedure for the automatic photometric determination of phosphate ions in natural waters was developed, based on the formation
of a colored ion associate of the reduced form of phosphomolybdic heteropoly anion with a polymethine dye, Astra Phloxine.
The detection limit was 5 μg P/L at the sample volume of 0.3 mL. 相似文献
10.
Gippius A. A. Zhurenko S. V. Büttgen N. Schädler M. Morozov I. V. Moskvin A. S. 《Physics of the Solid State》2019,61(5):723-727
Physics of the Solid State - An NMR analysis of 31P nuclei in metallic iron phosphide FeP has been performed both in a zero field and by sweeping the external magnetic field at several fixed... 相似文献