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11.
Gong H Garcia-Turiel J Vasilev K Vinogradova OI 《Langmuir : the ACS journal of surfaces and colloids》2005,21(16):7545-7550
The growth, morphology, and interaction/adhesion properties of supported poly(sodium 4-styrenesulfonate)/poly(allylamine hydrochloride) (PSS/PAH) and DNA/PAH multilayers were investigated by means of surface plasmon resonance spectroscopy, atomic force microscope (AFM) imaging, and AFM-related force measurements. Multilayers were assembled on a prelayer of poly(ethylenimine) (PEI) both with and without drying. SPR results showed a linear growth of the assembly in the case of PSS/PAH multilayers and nonlinear growth for DNA/PAH multilayers. Measurements of forces acting between a bare glass sphere and a multilayer-coated surface indicated repulsive or attractive forces, depending on surface charge, which suggests that, on approach, electrostatic forces dominate. On separation, we observed large pull-off forces in the case of positively charged multilayers and weak pull-off forces in the case negatively charged multilayers. Multiple adhesions and plateau regions observed on separation were interpreted in terms of a bridging of multiple polymer chains between the glass particle and the multilayer and a stretching of the polyelectrolyte loops. The dependence of the pull-off force on the number of deposited layers shows regular oscillations. 相似文献
12.
Denis S. Baranov Aleksey A. Ryabichev Victor I. Mamatyuk Yurii V. Gatilov Victor G. Kartsev Sergei F. Vasilevsky 《Mendeleev Communications》2012,22(2):114-116
Reaction between 2-alkyl-4-arylbut-3-yn-2-ols and guanidine in refluxing pyridine affords 2-amino-5,5-dialkyl-4-arylmethylidene-2-oxazolines. 相似文献
13.
Aleksey K. Alekseev I. Michael Navon 《International Journal of Computational Fluid Dynamics》2013,27(2):113-117
The uncertainty of temperature prediction from the heat flux error is estimated using first and second order adjoint equations. The adjoint codes developed for the inverse heat transfer problems provide the uncertainty estimation for the corresponding forward problems. Numerical tests corroborate the feasibility of fast uncertainty estimation using Hessian maximum eigenvalue obtained via second order adjoint equations. 相似文献
14.
Victor V. Dotsenko Arif I. Ismiev Anastasiya N. Khrustaleva Konstantin A. Frolov Sergey G. Krivokolysko Elena A. Chigorina Aleksey P. Snizhko Vladimir M. Gromenko Ivan S. Bushmarinov Rizvan K. Askerov Tatyana M. Pekhtereva Sergey Yu. Suykov Elena S. Papayanina Aleksandr V. Mazepa Abel M. Magerramov 《Chemistry of Heterocyclic Compounds》2016,52(7):473-483
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Technical Physics - Pt films with thickness h = 20–100 nm deposited on oxidized с-Si(100) substrate have been subjected to vacuum annealing at 500°C for 1 h, which resulted in... 相似文献
17.
Dmitri V. Konarev Aleksey V. Kuzmin Salavat S. Khasanov Alexander F. Shestakov Akihiro Otsuka Hideki Yamochi Hiroshi Kitagawa Rimma N. Lyubovskaya 《化学:亚洲杂志》2020,15(17):2689-2695
Two salts of the aromatic hydrocarbon decacyclene, {cryptand[2.2.2](Cs+)} (decacyclene.?) ( 1 ) and {Bu3MeP+}(decacyclene.?) ( 2 ), were obtained. In both salts, decacyclene.? radical anions formed channels occupied by cations. However, corrugated hexagonal decacyclene.? layers could be outlined in the crystal structure of 1 with several side‐by‐side C???C approaches. The decacyclene.? radical anions showed strong distortion in both salts, deviating from the C3 symmetry owing to the repulsion of closely arranged hydrogen atoms and the Jahn‐Teller effect. Radical anions showed intense unusually low energy absorption in the IR‐range, with maxima at 4800 and 6000 cm?1. According to the carculations, these bands can originate from the SOMO‐LUMO+1 and SOMO‐LUMO+2 transitions, respectively. Radical anions exhibited a S=1/2 spin state, with an effective magnetic moment of 1.72 μB at 300 K. The decacyclene.? spin antiferromagnetically coupled with a Weiss temperature of ?11 K. Spin ordering was not observed down to 1.9 K owing to spin frustration in the hexagonal decacyclene.? layers. 相似文献
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An efficient method for the synthesis of valuable N-, O-, and Si-containing 1Z,5Z-diene compounds was developed. The method comprises Cp2TiCl2-catalyzed homo- and cross-cyclomagnesiation of 1,2-dienes by Grignard reagents (RMgR′) to give 2,5-dialkylidenemagnesacyclopentanes in up to 96% yield. This approach was successfully used in the synthesis of 5Z,9Z-dienoic acids, precursors of acetogenins and insect pheromones. 相似文献
20.
Vyacheslav I. Supranovich Gennady I. Borodkin Aleksey Yu. Vorob’ev Vyacheslav G. Shubin 《Tetrahedron letters》2014
An unusual cleavage of the Cpy–Cpy bond in the reaction of 2,2′-bipyridine N,N′-diimine and its C-methyl substituted derivatives with acetylenes is described. The effect of the solvent on the yield of 7,7′-bipyrazolo[1,5-a]pyridine-2,2′,3,3′-tetracarboxylates and the products of cleavage of the Cpy–Cpy bond has been studied. The mechanism of the cleavage reaction is discussed on the basis of DFT calculations. 相似文献