排序方式: 共有105条查询结果,搜索用时 15 毫秒
81.
Incoherent combining of multiple laser beams with offset wavelengths into a single near-diffraction-limited beam is an effective solution to increasing energy brightness and scaling output power of high-power lasers. Volume Bragg gratings (VBGs) recorded in photo-thermo-refractive (PTR) glass allow spectral beam combining with a remarkably high spectral density of channels. Spectral beam combining (SBC) of five channels within 1-2 nm bandwidth around 1064 and 1550 nm into a single near-diffraction-limited beam with absolute efficiency 92-94% is demonstrated. Scaling of this technique to multi-kW power level is discussed. 相似文献
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83.
Dmitry Dordovskyi Oleksiy Dovgoshey Eugeniy Petrov 《P-Adic Numbers, Ultrametric Analysis, and Applications》2011,3(4):253-262
Let F(X) be the set of finite nonempty subsets of a set X. We have found the necessary and sufficient conditions under which for a given function τ: F(X) → ℝ there is an ultrametric on X such that τ(A) = diamA for every A ∈ F(X). For finite nondegenerate ultrametric spaces (X, d) it is shown that X together with the subset of diametrical pairs of points of X forms a complete k-partite graph, k ⩾ 2, and, conversely, every finite complete k-partite graph with k ⩾ 2 can be obtained by this way. We use this result to characterize the finite ultrametric spaces (X, d) having the minimal card{(x, y): d(x, y) = diamX, x, y ∈ X} for given card X. 相似文献
84.
Mykhailo I. Adamovskyi Oleksiy S. Artamonov Andriy V. Tymtsunik Oleksandr O. Grygorenko 《Tetrahedron letters》2014
An unusual rearrangement of a 1-oxa-6-azaspiro[2.5]octane derivative giving access to novel 5-substituted 2-azabicyclo[3.1.0]hexanes is described. The synthetic application of the reaction is demonstrated by the synthesis of N-Boc-2,3-methano-β-proline. The amino acid was prepared through a three-step synthesis from easily available reagents in an overall yield of 15%. 相似文献
85.
Oleksiy V. Klymenko Irina Svir Christian Amatore 《Electrochemistry communications》2010,12(10):1378-1382
In this article we investigate the origin of unexpected features appearing in voltammetry or double-step chronoamperometry of EE systems when the rate of comproportionation is extremely fast and the diffusion coefficients of the reactant and products highly differ. These features were noticed during the testing of our new software KISSA intended to solve any reaction mechanisms even when acute reaction fronts develop near the electrode surface or within the solution. To validate the principle of the new adaptive algorithm [C. Amatore, O. Klymenko, I. Svir, Electrochem. Commun. doi:10.1016/j.elecom.2010.06.009] implemented in KISSA we used analytical and numerical solutions for double-step chronoamperometry. This revealed that the peculiar current jumps stem from a rapid variation of the reaction front position when the starting material is still reducible at the electrode while the product of the second electron transfer is re-oxidized. The exact convergence between the predictions by these independent methods demonstrated that KISSA is perfectly accurate even under such extreme mechanistic conditions. 相似文献
86.
Oleksiy V. Grygorovych Sofia M. Moskalenko Bogdan A. Marekha Andrey O. Doroshenko 《Journal of fluorescence》2010,20(1):115-124
The new sensing materials based on the microsized silica gel powder with non-covalently immobilized structurally rigid analogs
of 2,6-distyrylpyrydine ((3E,5E)-3,5-dibenzylidene-8-phenyl-1,2,3,5,6,7-hexahydrodicyclopenta[b,e]pyridines) were developed and tested. Most of the investigated compositions demonstrate linear ratiometric fluorescence response
on pH in the physiologically important interval (pH 6–9). The compound with the greatest number of protolytic centers within the studied series demonstrated the widest pH sensitivity range, however in this case the analytical signal was the lowest. The prospects for the practical application
of the investigated materials in the fiber optics sensing devices were outlined. 相似文献
87.
Valeriya G. Makhankova Oleksiy V. Khavryuchenko Vladimir N. Kokozay Oleg V. Shishkin Brian W. Skelton 《Journal of solid state chemistry》2010,183(11):2695-2702
A facile one-pot procedure, or so-called “direct synthesis,” was used to prepare the novel heterometallic complexes [M2Mn(OAc)6(bpy)2], where M=Cu (1), Co (2), Zn (3), bpy=2,2′-bipyridyl, with high yields via oxidative dissolution of pure metals in a liquid phase. The complexes were characterized by an elemental analysis, single crystal X-ray diffraction method and FTIR. These complexes are proposed as precursors, whose thermal degradation may lead to the formation of solids possessing nano- to microsize levels of dispersity. The thermal behavior of the complexes obtained was studied by thermal analysis (TG/DTA/DTG) in both air and N2 and also by TPD mass-spectrometry in vacuo. The FTIR, X-ray powder diffraction (PXRD) and thermoanalytical data were used for the identification of the solid products of thermal degradation. The morphology and microstructure of the solid residues were analyzed, using scanning electron microscopy with energy dispersive X-ray microanalysis (SEM/EDX) at mkm and sub-micro levels. 相似文献
88.
Roth WJ Shvets OV Shamzhy M Chlubná P Kubů M Nachtigall P Čejka J 《Journal of the American Chemical Society》2011,133(16):6130-6133
Mild treatment of zeolite UTL results in degradation of its structure with preservation of the initially present dense layers connected by D4R "bridges". The lamellar product obtained through this 3D to 2D zeolite conversion has been structurally modified similar to methodologies applied to layered zeolite precursors, which show the opposite 2D to 3D zeolite transformation. 相似文献
89.
Oleksiy V. Kapustyan Pavlo O. Kasyanov Roman M. Taranets 《Journal of Mathematical Analysis and Applications》2021,493(2):124562
We prove local and global in time existence of non-negative weak solutions to the thin-film equation with absorption and obtain sufficient conditions for extra regularity of these solutions. Moreover, for the class of global strong solutions, we show existence of a trajectory attractor. 相似文献
90.