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排序方式: 共有542条查询结果,搜索用时 15 毫秒
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Nonlinear Dynamics - A validation of recent theoretical results on the stability effects of asynchronous parametric excitation is presented. In particular, the coexistence of both resonance and... 相似文献
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Synthesis of Ultra-High Molecular Weight Polyolefins of Regular Structure in Octafluorobutane Medium
Rasputin N. A. Yakovlev S. V. Artem’ev G. A. Rusinov P. G. Nifant’ev I. E. Nikonov I. L. Kopchuk D. S. 《Russian Journal of Applied Chemistry》2021,94(6):736-740
Russian Journal of Applied Chemistry - The suspension polymerization in octafluorobutane, initiated by Ziegler–Natta catalyst system, has been used to synthesize ultra-high molecular weight... 相似文献
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Anna V. Pomogaeva Anna S. Lisovenko Artem S. Zavgorodnii Alexey Y. Timoshkin 《Journal of computational chemistry》2023,44(3):218-228
Stabilization of hydrogen-substituted group 13–15 compounds H2EE′H2 (E = B, Al, Ga; E′ = P, As, Sb) by Lewis acids is considered at B3LYP/def2-TZVP, B3LYP-D3/def2-TZVP and M06-2X/def2-TZVP levels of theory. It is shown, that for many Lewis acids additional reactivity beyond the DA complex formation with H2EE′H2 monomer is expected. In case of complexation with E(C6F5)3, F/H exchange reactions with group 13 bound hydrides are predicted to be exothermic and accompanied by the activation energies which are smaller than dissociation of the complex into components. In case of complex formation with transition metal (TM) carbonyls, additional O → Al, TM–C → Al interactions are observed, which in several cases lead to cyclic structures. The most promising candidates for the experimental studies have been identified. Synthetic approaches to the most promising LA-only stabilized compounds are recommended. 相似文献
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Oleksandr P. Demchuk Bohdan V. Bobovskyi Bohdan V. Vashchenko Dr. Oleksandr V. Hryshchuk Artem Skreminskyi Dr. Anton V. Chernykh Dr. Viktoriia S. Moskvina Dr. Olga V. Hordiyenko Prof. Dr. Dmitriy M. Volochnyuk Prof. Dr. Oleksandr O. Grygorenko 《European journal of organic chemistry》2023,26(24):e202300292
Synthesis and physicochemical characterization of all possible cis- and trans-1,3-disubstituted cyclobutane-derived amines and carboxylic acids bearing mono-, di- and trifluoromethyl groups at the C-3 position is disclosed. Tetramethylammonium fluoride (TMAF)- or morpholinosulfur trifluoride (Morph-DAST)-mediated nucleophilic fluorination of appropriate cis- and trans-diastereomeric substrates was used as the key step for the preparation of CH2F- and CHF2-substituted derivatives. To obtain the corresponding cis- and trans-isomeric CF3-substituted derivatives, resolution of known 3-(trifluoromethyl)cyclobutanecarboxylic acid (obtained as a mixture of diastereomers) was applied. The proposed procedures were suitable for the preparation of corresponding fluoroalkyl-substituted cyclobutane-derived amines and carboxylic acids on up to 50 g scale. All 12 building blocks obtained were characterized by measuring dissociation constants (pKa) and lipophilicities (LogP, for model derivatives) to evaluate the effect of the fluoroalkyl substituents on their physicochemical properties relevant to further drug discovery applications. 相似文献
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ChemInform Abstract: Explaining Stability of Transition Metal Carbides — and Why TcC Does Not Exist.
Qinggao Wang Konstantin E. German Artem R. Oganov Huafeng Dong Oleg D. Feya Ya. V. Zubavichus V. Yu. Murzin 《ChemInform》2016,47(18):no-no
The formation of transition metal (M) carbides MxCy and trends of their stability are systematically investigated using the USPEX code within the DFT. 相似文献
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Using the Monte Carlo method, we address the influence of the Wiener and Poisson random noises on the behavior of oscillatory solutions to systems of stochastic differential equations (SDEs). For the linear and Van der Pol oscillators, we study the accuracy of estimates of the functionals of numerical solutions to SDEs obtained by the generalized explicit Euler method. For a linear oscillator, we obtain the exact analytical expressions for the mathematical expectation and the variance of the SDE solution. These expressions allow us to investigate the dependence of the accuracy of estimates of the solution moments on the values of SDE parameters, the size of meshsize, and the ensemble of simulated trajectories of the solution. For the Van der Pol oscillator, we study the dependence of the frequency and the damping rate of the oscillations of the mathematical expectation of SDE solution on the values of parameters of the Poisson component. The results of the numerical experiments are presented. 相似文献
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Artem N. Shevlyakov 《代数通讯》2017,45(9):3757-3767
A semigroup S is called an equational domain if any finite union of algebraic sets over S is algebraic. We give some necessary and su?cient conditions for a completely simple semigroup to be an equational domain. 相似文献