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208. Stereoselectivity of Electron and Energy Transfer in the Quenching of (S/R)-Ketoprofen-(S)-Tryptophan Dyad Excited State

Author

Ageeva, Aleksandra A., primary, Babenko, Simon V., additional, Magin, Ilya M., additional, Plyusnin, Victor F., additional, Kuznetsova, Polina S., additional, Stepanov, Alexander A., additional, Vasilevsky, Sergey F., additional, Polyakov, Nikolay E., additional, Doktorov, Alexander B., additional, and Leshina, Tatyana V., additional

Published
2020
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219. How do Migrants Turn Out to Be Extremists? Theoretical Models for a Sociological Analysis of Inclusion and Social Exclusion of Transnational Migrants in Everyday Life

Author

Rezaev, Andrey V., Lisitsyn, Pavel P., and Stepanov, Alexander M.

Abstract

Current publications in professional literature often discuss terrorism and extremism in the system of coordinates developed by jurisprudence where the different phenomena are eclectically combined and grouped for analytical purposes. Charles Tilly in his works insisted that the terms terror, terrorism, and terrorist do not identify causally coherent and distinct social phenomena but rather strategies that recur across a wide variety of actors and political situations. This paper tries to depict basic theoretical models and methodological framework for doing field sociological inquiry on the hottest issue in current migration studies which is how the reality of social exclusion in everyday life turns immigrants to the practices of ideological extremism. KEYWORDS: transnational migrants, extremism, everyday life, social inclusion and social exclusion of migrants

Published
2019
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220. Keynote Speech: Industrializing Software Development

Author

Stepanov, Alexander, Hutchison, David, editor, Kanade, Takeo, editor, Kittler, Josef, editor, Kleinberg, Jon M., editor, Mattern, Friedemann, editor, Mitchell, John C., editor, Naor, Moni, editor, Nierstrasz, Oscar, editor, Pandu Rangan, C., editor, Steffen, Bernhard, editor, Sudan, Madhu, editor, Terzopoulos, Demetri, editor, Tygar, Dough, editor, Vardi, Moshe Y., editor, Weikum, Gerhard, editor, Wu, Zhaohui, editor, Chen, Chun, editor, Guo, Minyi, editor, and Bu, Jiajun, editor

Published
2005
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222. The accuracy challenge of the DFT-based molecular assignment of 13C MAS NMR characterization of surface intermediates in zeolite catalysis

Author

Kolganov, A.A. (author), Gabrienko, Anton A. (author), Chernyshov, I. (author), Stepanov, Alexander G. (author), Pidko, E.A. (author), Kolganov, A.A. (author), Gabrienko, Anton A. (author), Chernyshov, I. (author), Stepanov, Alexander G. (author), and Pidko, E.A. (author)

Abstract

The influence of the model and method choice on the DFT predicted 13C NMR chemical shifts of zeolite surface methoxide species has been systematically analyzed. Twelve 13C NMR chemical shift calculation protocols on full periodic and hybrid periodic-cluster DFT calculations with varied structural relaxation procedures are examined. The primary assessment of the accuracy of the computational protocols has been carried out for the Si-O(CH3)-Al surface methoxide species in ZSM-5 zeolite with well-defined experimental NMR parameters (chemical shift, δ(13C) value) as a reference. Different configurations of these surface intermediates and their location inside the ZSM-5 pores are considered explicitly. The predicted δ value deviates by up to ±0.8 ppm from the experimental value of 59 ppm due to the varied confinement of the methoxide species at different zeolite sites (model accuracy). The choice of the exchange-correlation functional (method accuracy) introduces ±1.5 ppm uncertainty in the computed chemical shifts. The accuracy of the predicted 13C NMR chemical shifts for the computational assignment of spectral characteristics of zeolite intermediates has been further analyzed by considering the potential intermediate species formed upon methane activation by Cu/ZSM-5 zeolite. The presence of Cu species in the vicinity of surface methoxide increases the prediction uncertainty to ±2.5 ppm. The full geometry relaxation of the local environment of an active site at an appropriate level of theory is critical to ensure a good agreement between the experimental and computed NMR data. Chemical shifts (δ) calculated via full geometry relaxation of a cluster model of a relevant portion of the zeolite lattice site are in the best agreement with the experimental values. Our analysis indicates that the full geometry optimization of a cluster model at the PBE0-D3/6-311G(d,p) level of theory followed by GIAO/PBE0-D3/aug-cc-pVDZ calculations is the most suitable approach for the c, ChemE/Algemeen, ChemE/Inorganic Systems Engineering

Published
2020
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223. Nature of the Surface Intermediates Formed from Methane on Cu-ZSM-5 Zeolite: A Combined Solid-State Nuclear Magnetic Resonance and Density Functional Theory Study

Author

Kolganov, A.A. (author), Gabrienko, Anton A. (author), Yashnik, Svetlana A. (author), Pidko, E.A. (author), Stepanov, Alexander G. (author), Kolganov, A.A. (author), Gabrienko, Anton A. (author), Yashnik, Svetlana A. (author), Pidko, E.A. (author), and Stepanov, Alexander G. (author)

Abstract

The intermediates formed upon the interaction of methane with Cu-modified ZSM-5 zeolites (Cu/H-ZSM-5) have been analyzed with solid-state NMR spectroscopy and DFT methods. Methane activation by Cu/H-ZSM-5 zeolites gives rise to three distinct surface methoxy-like species (-O-CH3) detected by 13C MAS NMR spectroscopy with specific chemical shifts in the range of 53-63 ppm. DFT calculations on representative cluster models of different sites potentially present in Cu/H-ZSM-5 have been used to assign these signals to (i) methanol adsorbed on two neighboring Cu sites (Cu-(HOCH3)-Cu, 62.6 ppm), (ii) methanol adsorbed on zeolite Brønsted acid sites (52.9 ppm), and (iii) lattice-bound methoxy groups (Si-O(CH3)-Al, 58.6). The formation of these methoxy-like intermediates depends on the Cu loading and, accordingly, the type of Cu species in the Cu/H-ZSM-5 zeolite. For the sample with low (0.1 wt %) Cu loading containing exclusively mononuclear isolated Cu species, only the intermediates ii and iii have been detected. The Cu-bound intermediate (i) is formed upon methane activation by multinuclear Cu sites featuring Cu-O-Cu bridging moieties present in the materials with relatively higher Cu loading (1.38 wt %). The presented results indicate that methane activation by Cu/H-ZSM-5 can be promoted by both mono- and multinuclear Cu species confined in the zeolite matrix., Accepted Author Manuscript, ChemE/Inorganic Systems Engineering, ChemE/Algemeen

Published
2020
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229. Property–activity relations of multifunctional reactive ensembles in cation-exchanged zeolites: a case study of methane activation on Zn2+-modified zeolite BEA.

Author

Kolganov, Alexander A., Gabrienko, Anton A., Chernyshov, Ivan Yu., Stepanov, Alexander G., and Pidko, Evgeny A.

Abstract

The reactivity theories and characterization studies for metal-containing zeolites are often focused on probing the metal sites. We present a detailed computational study of the reactivity of Zn-modified BEA zeolite towards C–H bond activation of the methane molecule as a model system that highlights the importance of representing the active site as the whole reactive ensemble integrating the extra-framework ZnEF2+ cations, framework oxygens (OF2−), and the confined space of the zeolite pores. We demonstrate that for our model system the relationship between the Lewis acidity, defined by the probe molecule adsorption energy, and the activation energy for methane C–H bond cleavage performs with a determination coefficient R2 = 0.55. This suggests that the acid properties of the localized extra-framework cations can be used only for a rough assessment of the reactivity of the cations in the metal-containing zeolites. In turn, studying the relationship between the activation energy and pyrrole adsorption energy revealed a correlation, with R2 = 0.80. This observation was accounted for by the similarity between the local geometries of the pyrrole adsorption complexes and the transition states for methane C–H bond cleavage. The inclusion of a simple descriptor for zeolite local confinement allows transferability of the obtained property–activity relations to other zeolite topologies. Our results demonstrate that the representation of the metal cationic species as a synergistically cooperating active site ensembles allows reliable detection of the relationship between the acid properties and reactivity of the metal cation in zeolite materials. [ABSTRACT FROM AUTHOR]

Published
2022
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233. Managing Russian Science-Intensive Enterprises in the Emerging New Technological Paradigm

Author

VESELOVSKY, Mikhail Yakovlevich, SUGLOBOV, Alexander Evgenievich, ABRASHKİN, Mikhail Sergeyevich, KHOROSHAVİNA, Natalya Sergeevna, and STEPANOV, Alexander Annayarovich

Subjects
innovations, lcsh:Management. Industrial management, lcsh:HD28-70, science-intensive industries, science-intensive enterprises, lcsh:Business, lcsh:HF5001-6182, Science-Intensive Enterprises,Science-Intensive Industries,Innovations,Technological Paradigms, technological paradigms
Abstract

The main purpose of the work was to examine the characteristics and identify the most innovative ways to manage Russian science-intensive enterprises in the emerging new technological paradigm. Fundamental position, works of scientists authoritative in this field, and author's developments served as theoretical and methodological basis of the research. The main methods of the research were the methods of empirical knowledge. As a result of the work, it is proposed to redefine the economic development strategy of the Russian Federation from the established resource-based scenarios to the most progressive ones that imply improvement of scientific and technological development of a number of industries to competitive international levels, to new technological paradigms. The necessity is founded to strengthen the effectiveness of the science-intensive enterprises, which act as a "core" of the production of innovative products, point of formation of a new post-industrial technological paradigm and the foundation of long-term economic growth in Russia. The peculiarities of the activities of science-intensive enterprises in the context of improving the approach to planning and forecasting are revealed. The necessity of harmonization of managing the science-intensive enterprises and the strategies of the state development of scientific and industrial base are methodologically founded. A set of instruments of state support for science-intensive enterprises that allow to bring Russia to the path of sustainable economic growth based on innovation is provided.

Published
2016

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