排序方式: 共有127条查询结果,搜索用时 15 毫秒
51.
Igor Danilenko Tetyana Konstantinova Galina Volkova Valentina Glazunova 《Phase Transitions》2013,86(10):987-999
The aim of this study was to produce yttria-stabilized zirconia nanopowders from zirconium oxychloride and zirconium oxynitrate salts using a co-precipitation technique, and to investigate the influence of hydrostatic pressure on the phase transition in these powders. It is shown that synthesis conditions and calcination temperature have a strong influence on the nanopowder's agglomeration, as well as on the stability of the tetragonal phase to phase transition under pressure conditions. Doped zirconia nanopowders synthesized from oxynitrate salts are more agglomerated and more stable than the oxychloride-based powders. Increasing the role of interfacial energy in agglomerated nanopowders leads to an increase in the stability of the tetragonal phase in doped zirconia nanopowders systems obtained at low and high calcination temperatures. Formation of separated nanoparticles at middle calcination temperature leads to a decrease in the stability of the tetragonal phase to phase transition under hydrostatic pressure conditions. 相似文献
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Igor I. Yusipov Tetyana V. Laptyeva Anna Yu. Pirova Iosif B. Meyerov Sergej Flach Mikhail V. Ivanchenko 《The European Physical Journal B - Condensed Matter and Complex Systems》2017,90(4):66
We study the dynamics of a few-quantum-particle cloud in the presence of two- and three-body interactions in weakly disordered one-dimensional lattices. The interaction is dramatically enhancing the Anderson localization length ξ 1 of noninteracting particles. We launch compact wave packets and show that few-body interactions lead to transient subdiffusion of wave packets, m 2 ~ t α , α< 1, on length scales beyond ξ 1. The subdiffusion exponent is independent of the number of particles. Two-body interactions yield α ≈ 0.5 for two and three particles, while three-body interactions decrease it to α ≈ 0.2. The tails of expanding wave packets exhibit exponential localization with a slowly decreasing exponent. We relate our results to subdiffusion in nonlinear random lattices, and to results on restricted diffusion in high-dimensional spaces like e.g. on comb lattices. 相似文献
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A. V. Krylov A. Kh. Mokhammed V. V. Yegorova E. Ya. Borisova N. Yu. Borisova V. R. Flid 《Russian Chemical Bulletin》2012,61(6):1128-1132
The results of ring opening in styrene oxide by alcohols, amines, amino alcohols, and diamines were generalized. On low polarizing ability of the solvent, the main direction of the process is the formation of normal α-substituted products. The solvent effect on regioselectivity of the reaction was studied for N,N-diethylethylenediamine. The ratio of products correlates well with the value of dielectric constant for mixed aqueous-organic solvents and with the parameters of polarity E T and AN for neat solvents. 相似文献
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Alexander A. Kirichok Hennadii Tkachuk Yevhenii Kozyriev Oleh Shablykin Oleksandr Datsenko Dmitry Granat Tetyana Yegorova Yuliya P. Bas Vitalii Semirenko Iryna Pishel Vladimir Kubyshkin Dmytro Lesyk Oleksii Klymenko-Ulianov Pavel K. Mykhailiuk 《Angewandte Chemie (International ed. in English)》2023,62(51):e202311583
1-Azaspiro[3.3]heptanes were synthesized, characterized, and validated biologically as bioisosteres of piperidine. The key synthesis step was thermal [2+2] cycloaddition between endocyclic alkenes and the Graf isocyanate, ClO2S−NCO, to give spirocyclic β-lactams. Reduction of the β-lactam ring with alane produced 1-azaspiro[3.3]heptanes. Incorporation of this core into the anesthetic drug bupivacaine instead of the piperidine fragment resulted in a new patent-free analogue with high activity. 相似文献
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Vyacheslav O. Khavrus Nataliia V. Lemesh Svitlana V. Gordijchuk Andriy I. Tripolsky Tetyana S. Ivashchenko Mykola M. Biliy Peter E. Strizhak 《Reaction Kinetics and Catalysis Letters》2008,93(2):295-303
A simple method for producing unsupported nickel catalyst that can be used to synthesize multi-wall carbon nanotubes (MWNT)
has been developed. The yield of purified MWNTs is about 1.8 gmwnt/(gcat×h). 相似文献
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In present work, an effective method to research geometrically nonlinear free vibrations of elements of thin-walled constructions that can be modeled as laminated shallow shells with complex planform is applied. The proposed method is numerical–analytical. It is based on joint use of the R-functions theory, variational methods, Bubnov–Galerkin procedure and Runge–Kutta method. The mathematical formulation of the problem is performed in a framework of the refined first-order shallow shells theory. To implement the developed method, appropriate software was developed. New problems of linear and nonlinear vibrations of laminated shallow shells with clamped cutouts are solved. To confirm reliability of the obtained results, their comparison with the ones known in the literature is provided. Effect of boundary conditions is studied. 相似文献
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Belyaev Nikolay A. Beryozkina Tetyana V. Lubec Gert Dehaen Wim Bakulev Vasiliy A. 《Chemistry of Heterocyclic Compounds》2018,54(11):1050-1055
Chemistry of Heterocyclic Compounds - It was found that brief refluxing of N-hetarylcyclopentano[d][1,2,3]triazolines in methanol resulted in the elimination of nitrogen, accompanied by... 相似文献
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Synthesis and biological activity of novel N-(3-furan-2-yl-1-phenyl-1H-pyrazol-5-yl) amides derivatives 总被引:1,自引:0,他引:1
Jing-Qian Huo Liu-Yong Ma Zhe Zhang Zhi-Jin Fan Jin-Lin Zhang Tetyana V. Beryozkina Vasiliy A. Bakulev 《中国化学快报》2016,27(9):1547-1550
A series of novel N-(3-furan-2-yl-1-phenyl-1H-pyrazol-5-yl) amides derivatives were designed and synthesized. Their structures were confirmed by 1H NMR, 13C NMR and HRMS. All title compounds were evaluated for their herbicidal and antifungal activities. Preliminary bioassay results indicated that the title compounds showed good to moderate herbicidal activity at 1000 mg/L. Compound 6q presented the best activity against Digitaria sanguinalis (L) Scop., Amaranthus retroflexus L. and Arabidopsis thaliana with an inhibition degree of five. Compound 6d also showed an inhibition degree of five against D. sanguinalis. In addition, at 50 mg/L, most compounds exhibited good in vitro antifungal activity against Sclerotinia sclerotiorum, with compound 6c showing over 90% antifungal activity against S. sclerotiorum and Pellicularia sasakii. 相似文献