1,736,770 research outputs found
Boris Volkov. The Return of a Forgotten Name
No full textThe article for the first time presents the work of the writer of the Eastern emigration Boris Nikolaevich Volkov (1894–1954). He was known to contemporaries for his publications in Harbin, Shanghai, Paris, Prague and other cities, where he was published under various pseudonyms. However, he is now a forgotten author. The article analyzes two short stories by Volkov: “The Steppe Crow” and “The Descendant of Genghis Khan” from the perspective of the writer’s autobiography, as well as in the light of the cultural traditions of the Mongols. The analysis involved the “Ancient Mongolian Legend of Genghis Khan”, which helps to reveal the semantic core of the plot motives of the works related to the traditions of steppe hospitality. The most exotic of them is hospitable heterism. The plots of both works are based on autobiographical events and refer to the early period of the writer’s life, when he was a Civil War participant on the side of Kolchak. Sent by the admiral to Mongolia to oppose Ungern’s Pan-Mongol campaign, Volkov was sentenced to death by the baron. So he was forced to flee to China. The Mongols helped him in his dangerous journey. The twists and turns of this adventurous part of the biography are reflected in the two works under analysis. In them, Volkov appears as a real artist, whose works replenish the arsenal of ethnographic literature. Thematically, both stories belong to the corpus of works that develop an international theme in Russian literature of the early twentieth century. The characters of the stories learn the wise and poetic attitude of the Mongols to the world, to life and death, based on ancient traditions and customs
Fast analytical evaluation of intermolecular electrostatic interaction energies using the pseudoatom representation of the electron density. III. Application to crystal structures via the Ewald and direct summation methods
No full textThe previously reported exact potential and multipole moment (EP/MM) method for fast and accurate evaluation of the intermolecular electrostatic interaction energies using the pseudoatom representation of the electron density [Volkov, Koritsanszky & Coppens (2004). Chem. Phys. Lett. 391, 170-175; Nguyen, Kisiel & Volkov (2018). Acta Cryst. A74, 524-536; Nguyen & Volkov (2019). Acta Cryst. A75, 448-464] is extended to the calculation of electrostatic interaction energies in molecular crystals using two newly developed implementations: (i) the Ewald summation (ES), which includes interactions up to the hexadecapolar level and the EP correction to account for short-range electron-density penetration effects, and (ii) the enhanced EP/MM-based direct summation (DS), which at sufficiently large intermolecular separations replaces the atomic multipole moment approximation to the electrostatic energy with that based on the molecular multipole moments. As in the previous study [Nguyen, Kisiel & Volkov (2018). Acta Cryst. A74, 524-536], the EP electron repulsion integral is evaluated analytically using the Löwdin α-function approach. The resulting techniques, incorporated in the XDPROP module of the software package XD2016, have been tested on several small-molecule crystal systems (benzene, l-dopa, paracetamol, amino acids etc.) and the crystal structure of a 181-atom decapeptide molecule (Z = 4) using electron densities constructed via the University at Buffalo Aspherical Pseudoatom Databank [Volkov, Li, Koritsanszky & Coppens (2004). J. Phys. Chem. A, 108, 4283-4300]. Using a 2015 2.8 GHz Intel Xeon E3-1505M v5 computer processor, a 64-bit implementation of the Löwdin α-function and one of the higher optimization levels in the GNU Fortran compiler, the ES method evaluates the electrostatic interaction energy with a numerical precision of at least 10-5 kJ mol-1 in under 6 s for any of the tested small-molecule crystal structures, and in 48.5 s for the decapeptide structure. The DS approach is competitive in terms of precision and speed with the ES technique only for crystal structures of small molecules that do not carry a large molecular dipole moment. The electron-density penetration effects, correctly accounted for by the two described methods, contribute 28-64% to the total electrostatic interaction energy in the examined systems, and thus cannot be neglected
A.A. Volkov, Maritime Law
No full textA.A. Volkov, Maritime Law. In: Revue internationale de droit comparé. Vol. 25 N°4, Octobre-décembre 1973. pp. 985-986
Composition des textes chinois anciens : d'après la première partie (Outils de l'analyse formelle) du livre de Vladimir S. Spirin [ Dans une présentation de Karine Chemla et A. Volkov]
No full textL'article explore l'hypothèse selon laquelle l'on peut rendre compte de la distribution des parallélismes, en un sens généralisé, dans un texte canonique en en disposant les différentes parties dans un tableau, qui s'avère présenter constamment 3 lignes, 3 colonnes (et parfois 3 étages). Apparaissent alors des relations de groupes de phrases à groupes de phrases que l' interprétation du texte doit prendre en considération.Spirin Vladimir S., Chemla Karine, K. Volkov Alexeï. Composition des textes chinois anciens : d'après la première partie (Outils de l'analyse formelle) du livre de Vladimir S. Spirin [ Dans une présentation de Karine Chemla et A. Volkov]. In: Extrême-Orient, Extrême-Occident, 1991, n°13. Modèles et structures des textes chinois anciens : les formalistes soviétiques en sinologie, sous la direction de Viéra V. Lichtmann, Alexeï K. Volkov et Nathalie Bidart . pp. 31-58
Completeness and orthonormality of the Volkov states and the Volkov propagator in configuration space
Full text linkVolkov states and Volkov propagator are the basic analytical tools to investigate QED processes occurring in the presence of an intense plane-wave electromagnetic field. In the present paper we provide alternative and relatively simple proofs of the completeness and of the orthonormality at a fixed time of the Volkov states. Concerning the completeness, we exploit some known properties of the Green's function of the Dirac operator in a plane wave, whereas the orthonormality of the Volkov states is proved, relying only on a geometric argument based on the Gauss theorem in four dimensions. In relation with the completeness of the Volkov states, we also study some analytical properties of the Green's function of the Dirac operator in a plane wave, which we explicitly prove to coincide with the Volkov propagator in configuration space. In particular, a closed-form expression in terms of modified Bessel functions and Hankel functions is derived by means of the operator technique in a plane wave and different asymptotic forms are determined. Finally, the transformation properties of the Volkov propagator under general gauge transformations and a general gauge-invariant expression of the so-called dressed mass in configuration space are presented
A.A. Volkov, Maritime Law
No full textA.A. Volkov, Maritime Law. In: Revue internationale de droit comparé. Vol. 25 N°4, Octobre-décembre 1973. pp. 985-986
Data and code related to "A microfluidic platform for in situ studies of bacteria electroporation", by Volkov et al.
No full textThis item contains microscopy data, analysis code and data for figures related to the publication: Volkov et al., "A microfluidic platform for in situ studies of bacteria electroporation".
The study presents a microfluidic platform capable of single-cell electroporation with in situ microscopy and demonstrates delivery of DNA into bacteria.
Data has been acquired at the Dept. Materials Science and Engineering and Dept. of Cell and Molecular Biology, Uppsala University.
A detailed list of files and file organization can be found in the readme text file
On the calculation of the electrostatic potential, electric field and electric field gradient from the aspherical pseudoatom model. II. Evaluation of the properties in an infinite crystal
No full textThe previously reported exact potential and multipole moment (EP/MM) method for fast and precise evaluation of the intermolecular electrostatic interaction energies in molecular crystals using the pseudoatom representation of the electron density [Nguyen, Macchi & Volkov (2020), Acta Cryst. A76, 630–651] has been extended to the calculation of the electrostatic potential (ESP), electric field (EF) and electric field gradient (EFG) in an infinite crystal. The presented approach combines an efficient Ewald-type summation (ES) of atomic multipoles up to the hexadecapolar level in direct and reciprocal spaces with corrections for (i) the net polarization of the sample (the ‘surface term’) due to a net dipole moment of the crystallographic unit cell (if present) and (ii) the short-range electron-density penetration effects. The rederived and reported closed-form expressions for all terms in the ES algorithm have been augmented by the expressions for the surface term available in the literature [Stenhammar, Trulsson & Linse (2011), J. Chem. Phys. 134, 224104] and the exact potential expressions reported in a previous study [Volkov, King, Coppens & Farrugia (2006), Acta Cryst. A62, 400–408]. The resulting algorithm, coded using Fortran in the XDPROP module of the software package XD, was tested on several small molecular crystal systems (formamide, benzene, l-dopa, paracetamol, amino acids etc.) and compared with a series of EP/MM-based direct-space summations (DS) performed within a certain number of unit cells generated along both the positive and negative crystallographic directions. The EP/MM-based ES technique allows for a noticeably more precise determination of the EF and EFG and significantly better precision of the evaluated ESP when compared with the DS calculations, even when the latter include contributions from an array of symmetry-equivalent atoms generated within four additional unit cells along each crystallographic direction. In terms of computational performance, the ES/EP/MM method is significantly faster than the DS calculations performed within the extended unit-cell limits but trails the DS calculations within the reduced summation ranges. Nonetheless, the described EP/MM-based ES algorithm is superior to the direct-space summations as it does not require the user to monitor continuously the convergence of the evaluated properties as a function of the summation limits and offers a better precision–performance balance
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