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We study the Leibniz n-algebra Un(∑),whose multiplication is defined viathe bracket of a Leibniz algebra ∑ as[x1,...,xn]=[x1,[...,[xn-2,[xn-1,xn]]...]].Weshow that Un(∑) is simple if and only if ∑ is a simple Lie algebra.An analog of Levi'stheorem for Leibniz algebras in Un(Lb) is established and it is proven that the Leibnizn-kernel of Un(Σ) for any semisimple Leibniz algebra Σ is the n-algebra Un(Σ). 相似文献
2.
A model is proposed for superplastic deformation of materials, based on the concept of cooperative grain-boundary slip. The
conditions for superplastic deformation are obtained as conditions for coherent shear bands. Analysis of the temperature dependence
of the limits of the stress interval for superplastic flow is used as a basis for the introduction of two types of threshold
stress that elucidate the cause of the ambiguity in the interpretation of exisiting experimental results.
Fiz. Tverd. Tela (St. Petersburg) 39, 2179–2185 (December 1997) 相似文献
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Resonance Raman scattering (RS) spectra of a ZnCdSe/ZnSe sample containing a single quantum well and quantum well-based open nanowires were studied at T=300 K. The longitudinal optical (LO) phonons involved in the formation of the observed spectra of the quantum-well and nanowire regions differ noticeably in energy. The LO phonon energies in the structures under study were calculated taking into account the compositional effect (doping of Cd into ZnSe) and biaxial strain. When excited in the exciton resonance region, RS is shown to occur via free (extended) excitonic states with the involvement of LO phonons of the ZnCdSe strained layer with final wave vectors near the Brillouin zone center. When excited below the excitonic resonance in the ZnCdSe layer, resonance scattering via localized exciton states provides a noticeable contribution to the observed RS lines. Because of the finite size of a localized state, phonons with large wave vectors are involved in these scattering processes. The RS lines produced under excitation in the excitonic region of the thick barrier layers are due to scattering from the ZnSe barrier phonons. 相似文献
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Vladimir I. Bregadze Andrey A. Semioshkin Julia N. Las'kova Maria Ya. Berzina Irina A. Lobanova Igor B. Sivaev Mikhail A. Grin Rustam A. Titeev Dmitry I. Brittal Olga V. Ulybina Anastasija V. Chestnova Anastasija A. Ignatova Alexey V. Feofanov Andrey F. Mironov 《应用有机金属化学》2009,23(9):370-374
Conjugates of chlorin e6 with closo‐dodecaborate and cobalt bis(dicarbollide) anions were synthesized for the first time in high yields using the advanced ‘click’ methodology. In vitro study on A549 human lung adenocarcinoma cells revealed that the synthesized boronated conjugates are able to penetrate and accumulate in cancer cells, but their intracellular concentration is not sufficient for effective photodynamic and boron neutron capture therapy of cancer. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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Marina Tikhonova Yuliya Kuzminova Xiaoying Fang Weiguo Wang Rustam Kaibyshev 《哲学杂志》2013,93(36):4181-4196
The effect of processing and annealing temperatures on the grain boundary characters in the ultrafine-grained structure of a 304-type austenitic stainless steel was studied. An S304H steel was subjected to multidirectional forging (MDF) at 500–800°C to total strains of ~4, followed by annealing at 800–1,000°C for 30 min. The MDF resulted in the formation of ultrafine-grained microstructures with mean grain sizes of 0.28–0.85 μm depending on the processing temperature. The annealing behaviour of the ultrafine-grained steel was characterized by the development of continuous post-dynamic recrystallization including a rapid recovery followed by a gradual grain growth. The post-dynamically recrystallized grain size depended on both the deformation temperature and the annealing temperature. The recrystallization kinetics was reduced with an increase in the temperature of the preceding deformation. The grain growth during post-dynamic recrystallization was accompanied by an increase in the fraction of Σ3n CSL boundaries, which was defined by a relative change in the grain size, i.e. a ratio of the annealed grain size to that evolved by preceding warm working (D/D0). The fraction of Σ3n CSL boundaries sharply rose to approximately 0.5 in the range of D/D0 from 1 to 5, which can be considered as early stage of continuous post-dynamic recrystallization. Then, the rate of increase in the fraction of Σ3n CSL boundaries slowed down significantly in the range of D/D0 > 5. A fivefold increase in the grain size by annealing is a necessary condition to obtain approximately 50% Σ3n CSL boundaries in the recrystallized microstructure. 相似文献
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Ekaterina Chainikova Sergey Khursan Alfia Yusupova Alexander Lobov Marat Abdullin Rustam Safiullin 《Tetrahedron letters》2018,59(34):3267-3271
During the photooxidation of aromatic azides containing a secondary N–H bond at the para-position, a sequence of intramolecular transformations of nitroso oxides led to the formation of heterocyclic oximes along with the corresponding nitroso and nitro compounds. 相似文献
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Molecular hydrogen is known to form stable, "nonclassical" sigma complexes with transition metal centers that are stabilized by donor-acceptor interactions and electrostatics. In this computational study, we establish that strong H2 sorption sites can be obtained in metal-organic frameworks by incorporating open transition metal sites on the organic linkers. Using density functional theory and energy decomposition analysis, we investigate the nature and characteristics of the H2 interaction with models of exposed open metal binding sites {half-sandwich piano-stool shaped complexes of the form (Arene)ML(3- n)(H2)n [M=Cr, Mo, V(-), Mn(+); Arene = C6H5X (X=H, F, Cl, OCH3, NH2, CH3, CF3) or C6H3Y2X (Y=COOH, X=CF3, Cl; L=CO; n=1-3]}. The metal-H2 bond dissociation energy of the studied complexes is calculated to be between 48 and 84 kJ/mol, based on the introduction of arene substituents, changes to the metal core, and of charge-balancing ligands. Thus, design of the binding site controls the H2 binding affinity and could be potentially used to control the magnitude of the H2 interaction energy to achieve reversible sorption characteristics at ambient conditions. Energy decomposition analysis illuminates both the possibilities and present challenges associated with rational materials design. 相似文献
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Rustam T. Iminov Andrey A. Tolmachev Yulian M. Volovenko Oleg V. Shishkin 《Tetrahedron》2009,65(41):8582-586
The reaction of 2-aminobenzamides with 2-oxocyclopentane-, 2-oxocyclohexane-, and 2-oxocycloheptaneacetic acids esters was found to give 7a,8,9,10-tetrahydrocyclopenta[2,3]pyrrolo[1,2-a]quinazoline-6,12(7H,11H)-diones, 7,7a,8,9,10,11-hexahydro-6H-indolo[1,7a-a]quinazoline-6,13(12H)-diones, and 7a,8,9,10,11,12-hexahydrocyclohepta[2,3]pyrrolo[1,2-a]quinazoline-6,14(7H,13H)-diones, respectively. The relative configuration with the cis-fused butyrolactam and cycloalkane rings was assigned to the prepared compounds on the basis of an X-ray crystallographic study. 相似文献
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Rustam T. Iminov Anton V. Tverdokhlebov Andrey A. Tolmachev Yulian M. Volovenko Svetlana V. Shishkina Oleg. V. Shishkin 《Tetrahedron》2012,68(14):3098-3102
Heating of N-{2-[(R-amino)carbonyl]phenyl}prolinamides in triethyl orthoformate solution was found to give 6-R-5,6,6a,8,9,10,10a,11-octahydropyrrolo[1′,2′:3,4]imidazo[1,2-a]quinazoline-5,11-diones. Similar reaction of N-{2-[(R-amino)carbonyl]phenyl}thiazolidine-4-carboxamides afforded 6-R-5,6,6a,10,10a,11-hexahydrothiazolo[3′,4′:3,4]imidazo[1,2-a]quinazoline-5,11-diones. The relative configuration of C-6a and C-10a centres of the tetracyclic compounds obtained was assigned as trans on the basis of X-ray crystallographic study. 相似文献