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101.
Lenka Blažková Lenka Malinová Václava Benešová Jan Roda Jiří Brožek 《Journal of polymer science. Part A, Polymer chemistry》2017,55(13):2203-2210
A successful preparation of polyamide 4 nanofibers via electrostatic spinning with diameters close to 100 nm is described. Polyamide 4 was prepared by the anionic ring‐opening polymerization of 2‐pyrrolidone and characterized. The effect of the system parameters (i.e., molar mass of the polymer, the solvent system) and the process parameters (i.e., the electrode‐to‐collector distance) during the electrostatic spinning have been studied. The morphology of the polyamide 4 fiber layers is given except molar mass of the polymer and the concentration of its solution primarily by the conformation of polyamide chains due to polyelectrolyte effect which was confirmed by viscosity measurements. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 2203–2210 相似文献
102.
103.
Birnšteinová Š. Hnatič M. Lučivjanský T. Mižišin L. Škultéty V. 《Theoretical and Mathematical Physics》2019,200(3):1335-1347
Theoretical and Mathematical Physics - We study an instructive model of the directed percolation process near its second-order phase transition between absorbing and active states. We first express... 相似文献
104.
Snežana Jovanović Ralph Puchta Olivera Klisurić 《Journal of Coordination Chemistry》2016,69(5):735-747
The crystal structure of K[PtCl3(caffeine)] was determined. The coordination geometry around platinum is square-planar formed by N9 of the caffeine ligand and three Cl? ions. The bond lengths and angles of K[PtCl3(caffeine)] were compared with those reported for [PtCl3(caffeine)]? and K[PtCl3(theobromine)]. At the level of the statistical significance of the data we have compared, no differences in the bond distances and angles for any of these compounds were noticed. Weak interactions between K+ and Cl? are responsible for the formation of 1-D polymeric chains in the crystal structure of the complex. The interactions of K[PtCl3(caffeine)] with inosine (Ino) and guanosine-5′-monophosphate (5′-GMP) were studied by 1H NMR spectroscopy at 295 K in D2O in a molar ratio of 1 : 1. The results indicate formation of the reaction product [PtCl3(Nu)] (Nu=Ino or 5′-GMP) with the release of caffeine from the coordination sphere of the starting complex. The higher stability of the bond between the Pt(II) ion and Ino or 5′-GMP compared to the stability of the platinum–caffeine bond is confirmed by density functional theory calculations (B3LYP/LANL2DZp) using as models 9-methylhypoxanthine and 9-methylguanine. 相似文献
105.
Žarko P. Barbarić Stojadin M. Manojlović Boban P. Bondžulić Milenko S. Andrić Srđan T. Mitrović 《Optik》2014
New relationship of displacement signal using opposite sectors on a quadrant photodiode is derived. Standard and new displacement signals are analyzed in details. Through MATLAB® laser tracking simulation models, based on common and suggested approaches, detailed analysis is performed, and it is shown that better results for the new relationship signal processing are obtained. Within new relationship of displacement signal, the sensitivity of the system to the displacement of the spot increases and, hence, provides better accuracy in positioning up to 30%. 相似文献
106.
Katarina Leko Marko Hanževački Dr. Zlatko Brkljača Dr. Katarina Pičuljan Dr. Rosana Ribić Dr. Josip Požar 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(23):5208-5219
The effects of solvent and temperature on the complexation of adamantyl mannoside with β-cyclodextrin and 6-O-monotosyl-6-deoxy-β-cyclodextrin were explored experimentally and by means of molecular dynamics simulations. Efficient binding was observed only in hydrogen-bonded solvents, which indicated solvophobically driven complexation. The stability of the inclusion complex was considerably higher in aqueous media. A pronounced temperature dependence of ΔrH○ and ΔrS○, resulting in perfect enthalpy–entropy compensation, was observed in water. The complexation thermodynamics was in line with classical rationale for the hydrophobic effect at lower temperatures and the nonclassical explanation at higher temperatures. This finding linked cyclodextrin complexation thermodynamics with insights regarding the effect of temperature on the hydration water structure. The complexation enthalpies and entropies were weakly dependent on temperature in organic media. The signs of ΔrH○ and ΔrS○ were in accordance with the nonclassical hydrophobic (solvophobic) effect. The structures of the optimized product corresponded to those deduced spectroscopically, and the calculated and experimentally obtained values of ΔrG○ were in very good agreement. This investigation clearly demonstrated that solvophobically driven formation of cyclodextrin complexes could be anticipated in structured solvents in general. However, unlike in water, adamantane and the host cavity behaved solely as structure breakers in the organic media explored so far. 相似文献
107.
A series of enantioenriched six-membered metallocyclic amidomagnesium naphtholates were prepared and used to probe the structure–reactivity/selectivity relationships of heteroleptic magnesium base complexes within asymmetric deprotonation reactions. An effective complex was identified and applied within enantioselective enolisation processes, delivering good levels of enantioselectivity and also revealing key structural requirements for achieving such selectivity. 相似文献
108.
Korać Jelena Todorović Nina Zakrzewska Joanna Žižić Milan Spasojević Ivan 《Structural chemistry》2018,29(5):1533-1541
Structural Chemistry - Epinephrine (Epi) is a physiologically important catecholamine. Molecular conformation of Epi controls the interactions with other molecules and its biological effects. There... 相似文献
109.
The influence of the flashlamp pump current pulse shape on Er:YAG laser efficiency and laser rod thermal focusing was studied theoretically and experimentally. Two pulse shapes, PFN (Pulse Forming Network) and VSP (Variable Square Pulse), were considered. Theoretical modeling and experimental measurements show that the pump pulse shape itself does not have a significant influence on the Er:YAG laser efficiency or thermal focusing. Instead, the major parameter influencing Er:YAG laser efficiency and thermal focusing was found to be the overall pulse duration. For PFN pulses, rise and fall times directly define the overall pulse duration, and therefore do have influence on thermal focusing. By contrast, VSP pulse duration is defined by the externally controlled on-time of the switching transistor. For square shaped pulses, short rise and fall times do not have a direct beneficial influence on thermal lensing. 相似文献
110.
M. Hannoun N. Blažević D. Kolbah F. Kajfež 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-2):125-126
Abstract Bis(trimethylsilyl)peroxide (BSPO) can be used for chemo- and stereoselective generation of P=O group by oxygenation of P(III) centre and transformation of P=S and P=Se groups. 相似文献