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Fedorov IA Zhuravlev YN Berveno VP 《Physical chemistry chemical physics : PCCP》2011,13(13):5679-5686
We investigated the electronic structure of crystalline naphthalene and anthracene within the framework of density functional theory including van der Waals interactions (DFT-D). It is established that for better agreement with experimental values it is necessary to use the increased values of the van der Waals radii, which is caused by an overestimated value of the van der Waals interactions in crystalline linear oligoacenes. Utilization of the DFT-D leads to a correct account of the dispersion forces, which results in a high precision of the computed lattice parameters and cohesive energy. Based on the relaxed crystal structures, we have computed the total and deformation electron density and determined the mechanism of chemical bonds formation in crystals of naphthalene and anthracene. It has been established that the chemical bond in molecular crystals is formed under the influence of not only intramolecular but also intermolecular interactions. On the basis of the Mulliken population analysis it was revealed that two C(3) atoms in naphthalene (or C(3) and C(4) in anthracene) have a positive charge and the population of the rest of the carbon atoms increased, as compared with isolated molecule. 相似文献
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V. V. Ivanov P. V. Egorov V. I. Klimov L. A. Kolpakova A. A. Malyshin L. F. Tugolokova V. V. Yunnikov V. P. Berveno 《Journal of Applied Mechanics and Technical Physics》1994,35(4):628-633
Kemerovo. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, No. 4, pp. 153–159, July–August, 1994. 相似文献
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M. A. Bondarenko A. V. Berveno V. P. Berveno E. O. Pentsak S. Yu. Lyrshchikov 《Physics of Particles and Nuclei Letters》2011,8(10):1040-1042
Porous carbon material from anthracite (2.5% of ash) produced at different activation temperatures with different burning
degree is studied. According to the data of IR-spectroscopy and element analysis, oxidation results in the removal of aliphatic
groups and the formation of oxygen-containing groups. Air oxidation causes formation of fractures, meso- and macropores. 相似文献
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A. V. Berveno V. P. Berveno M. A. Bondarenko E. O. Pentsak S. Yu. Lyrshchikov 《Physics of Particles and Nuclei Letters》2011,8(10):1037-1039
Main regularities in the formation of nanotexture and structure of carbon porous materials and development of pores in Kuzbass
anthracites were considered. Basic principles of the production of carbon sorbents for efficient separation of gases such
as methane and helium, hydrogen and carbon monoxide, were studied. Sorbents produced from Kuzbass coals were analyzed with
the help of gas chromatography, SEM with element analyzer, sorpometry, and gas porometry. The literature data on the size
of pores and associates of nanofragments were compared to the width of pores andsize of entrance windows in models of CMS
(carbon molecular sieve) nanofragments, which were estimated with the help of quantum chemical modeling in MOPAC/PM-3 semiempirical
program. The work resulted in the production of carbon molecular sieves for extraction of hydrogen from gas mixtures and in
obtaining the data on the main characteristics of sorbents produced. 相似文献
5.
Effect of poly (lactic acid)‐graft‐glycidyl methacrylate as a compatibilizer on properties of poly (lactic acid)/banana fiber biocomposites
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The main aim of this study was to synthesis of poly (lactic acid) (PLA)‐graft‐glycidyl methacrylate (GMA) as well as its influence on the properties of PLA/banana fiber biocomposites. PLA‐graft‐GMA graft copolymer (GC) was synthesized by melt blending PLA with GMA using benzoyl peroxide and dicumyl peroxide as initiators. Graft copolymerization was confirmed by FTIR and 1H‐NMR spectroscopic studies. PLA/silane treated banana fiber (SiB) biocomposites with various GC concentrations were prepared by melt blending followed by injection molding techniques. The influence of GC content on the mechanical, thermal and moisture resistance properties of the composite was investigated. The addition of 15 wt% GC content in the biocomposite provided optimum tensile and flexural strength, which is attributed to the greater compatibility between fiber and PLA matrix. The thermal properties of biocomposites have been evaluated using thermogravimetric analysis which provided evidence of improved interfacial adhesion between SiB and PLA by the addition of GC. Additionally, GC enhanced the moisture absorption resistance of biocomposites. These results indicated that GC is indeed a good candidate as a compatibilizing agent to improve the compatibility in PLA/fiber biocomposites. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
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Berveno V. P. Bryukhovetskaya L. V. Voronkov M. I. Yarosh O. I. 《Russian Chemical Bulletin》2003,52(3):764-767
The onset temperature of radical formation in the stepwise thermolysis of polyunsaturated polycarbosilane —[(Me2SiCC)4Me2SiCH=CH]
n
— with n > 2 was found by ESR spectroscopy. Beginning from 230°C two types of radicals are formed. The first radical arises on heating to 240°C due to the delocalization of unpaired electrons over the polyunsaturated polymer systems to H atoms of the Et groups of the polymer. The second radical appears at temperatures 240°C due to delocalization to H atoms of the Me groups through the vacant 3d-orbital of the Si atom. 相似文献
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