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排序方式: 共有251条查询结果,搜索用时 15 毫秒
1.
Jürgen Kurths M. Carmen Romano Marco Thiel Grigory V. Osipov Mikhail V. Ivanchenko István Z. Kiss John L. Hudson 《Nonlinear dynamics》2006,44(1-4):135-149
We present two different approaches to detect and quantify phase synchronization in the case of coupled non-phase coherent
oscillators. The first one is based on the general idea of curvature of an arbitrary curve. The second one is based on recurrences
of the trajectory in phase space. We illustrate both methods in the paradigmatic example of the R?ssler system in the funnel
regime. We show that the second method is applicable even in the case of noisy data. Furthermore, we extend the second approach
to the application of chains of coupled systems, which allows us to detect easily clusters of synchronized oscillators. In
order to illustrate the applicability of this approach, we show the results of the algorithm applied to experimental data
from a population of 64 electrochemical oscillators. 相似文献
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Prof. Evgeny A. Kataev Dr. Grigory V. Kolesnikov Rene Arnold Herman V. Lavrov Prof. Victor N. Khrustalev 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(11):3710-3714
Inorganic anions were used as templates in the reaction between a diamine and an activated diacid to form macrocyclic amides. The reaction conditions were found to perform the macrocyclization sufficiently slow to observe a template effect. A number of analytical methods were used to clarify the reaction mechanisms and to show that the structure of the intermediate plays a decisive role in determining the product distribution. For the macrocyclization under kinetic control, it was shown that the amount of a template, the conformational rigidity of building blocks, and the anion affinities of reaction components and intermediates are important parameters that one should take into consideration to achieve high yields. 相似文献
5.
Madhu Kumar Reddy Kandula Mohan Gundluru Bakthavatchala Reddy Nemallapudi Sravya Gundala Peddanna Kotha Grigory V. Zyryanov Sridevi Chadive Suresh Reddy Cirandur 《Journal of heterocyclic chemistry》2021,58(1):172-181
A novel series of piperazine-1,2,3-triazole bearing dimethyl(((2-(4-((1H-1,2,3-triazole-4-yl)methyl)piperazin-1-yl)ethylamino)(2-hydroxyaryl)methyl)phosphonate derivatives have been prepared via copper-catalyzed azide-alkyne 1,3-dipolar cycloaddition (CuAAC) (Click Reaction) and Schiff base reactions. The synthesized compounds were confirmed by spectral characterization (1H, 13C and 31P NMR, and mass). The title compounds were evaluated for in vitro alpha glucosidase enzyme inhibition and in vitro antioxidant activity using DPPH and H2O2 methods. 相似文献
6.
The formation of heterophase polymers via phase separation in the course of curing reaction in a blend of a thermosetting oligomer with a rubber modifier is considered. The interference of thermodynamic and kinetic factors that define the morphology of the material being formed is discussed. The need for a kinetic theory of cure-induced phase separation is established, and an approach of this kind is proposed. On the basis of this approach a simple quantitative criterion of deflection of the phase-separating system from the thermodynamic equilibrium is given. 相似文献
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Bakthavatchala Reddy Nemallapudi Grigory V. Zyryanov Balakrishna Avula Mallikarjuna Reddy Guda Sravya Gundala 《Journal of heterocyclic chemistry》2019,56(12):3324-3332
An effective and suitable meglumine‐catalyzed high‐yielding process was considered and engaged for the synthesis of new bis(indolyl)methanes at ambient temperature under aqueous conditions. The catalytic reaction proceeds very smoothly. Clean reaction, ease of product isolation/purification, easily available reactant and ecofriendly reaction conditions are the notable advantages of the present methodology. All the title compounds were characterized by IR, 1H, 13C NMR, and mass spectra. All the synthesized compounds were tested for antimicrobial activity, and the results indicated that most of the synthesized compounds exhibited excellent activity against the tested microorganisms. In this new series, compound 3l , having nitro substituent on the aromatic ring, showed exceptional potent inhibitory activity against Pseudomonas aeruginosa and Penicillium chrysogenum. 相似文献
9.
Marina A. Katkova Galina S. Zabrodina Evgeny V. Baranov Maria S. Muravyeva Evgeny A. Kluev Andrey S. Shavyrin Grigory Yu Zhigulin Sergey Yu Ketkov 《应用有机金属化学》2018,32(7)
The development of contrast agents specifically designed for high‐field magnetic resonance imaging (MRI) is required because the relaxation efficiency of classic Gd(III) contrast agents significantly decreases with increasing magnetic field strengths. With an idea of exploring the unique structure of lanthanide (Ln) 15‐MC‐5 metallacrowns, we developed a series of water‐soluble Gd(III) aqua‐complexes, bearing aminohydroxamate (glycine, α‐alanine, α‐phenylalanine and α‐tyrosine) ligands, with increasing number of water molecules directly coordinated to the Gd(III) ion: Gd(H2O)4[15‐MCCu(II)Glyha‐5](Cl)3 ( 1 (Gd)), Gd(H2O)4[15‐MCCu(II)Alaha‐5](Cl)3 ( 2 (Gd)), Gd(H2O)3[15‐MCCu(II)Phalaha‐5](Cl)3 ( 3 (Gd)) and Gd(H2O)3[15‐MCCu(II)Tyrha‐5](Cl)3 ( 4 (Gd)). In these systems, the Ln(III) central ion is coordinated by five oxygen donor atoms of the ligands and three or four inner‐sphere water molecules. The X‐ray crystal structure of metallacrown Ln(H2O)3,4[15‐MCCu(II)Rha‐5]3+ agrees with density functional theory predictions. The calculations demonstrate that the exchange of coordinated water molecules can proceed easily, resulting in increased relaxivity parameters. The longitudinal relaxivities (r1) of 1 (Gd)– 4 (Gd) in water at ultrahigh magnetic field of 9.4 T were determined to be 11.5, 14.8, 13.9 and 12.2 mM?1 s?1, respectively. The ability to increase the number of Ln(III) inner‐sphere water molecules up to four, the planar metallacrown structure and the rich hydration shell due to strong hydrogen bonds between the [15‐MC‐5] moiety and bulk water molecules provide new opportunities for potential MRI applications. 相似文献
10.
Grigory Bordyugov Nils Fischer Harald Engel Oliver Steinbock 《Physica D: Nonlinear Phenomena》2010,239(11):766-4694
We report results on dispersion relations and instabilities of traveling waves in excitable systems. Experiments employ solutions of the 1,4-cyclohexanedione Belousov-Zhabotinsky reaction confined to thin capillary tubes which create a pseudo-one-dimensional system. Theoretical analyses focus on a three-variable reaction-diffusion model that is known to reproduce qualitatively many of the experimentally observed dynamics. Using continuation methods, we show that the transition from normal, monotonic to anomalous, single-overshoot dispersion curves is due to an orbit flip bifurcation of the solitary pulse homoclinics. In the case of “wave stacking”, this anomaly induces attractive pulse interaction, slow solitary pulses, and faster wave trains. For “wave merging”, wave trains break up in the wake of the slow solitary pulse due to an instability of wave trains at small wavelength. A third case, “wave tracking” is characterized by the non-existence of solitary waves but existence of periodic wave trains. The corresponding dispersion curve is a closed curve covering a finite band of wavelengths. 相似文献