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31.
Valiullina Z. R. Galeeva A. M. Miftakhov M. S. 《Russian Journal of Organic Chemistry》2021,57(9):1461-1465
Russian Journal of Organic Chemistry - The Reformatsky reaction of (3R,4R)-4-acetoxy-3-((1R)-1-{[tert-butyl(dimethyl)silyl]oxy}ethyl)azetidin-2-one with ethyl 4-bromo-3-oxopentanoate gave... 相似文献
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Turyanskiy A. G. Vorob’ev N. S. Gizha S. S. Makushina V. A. Mikhal’kov Yu. M. Smirnov A. V. Pirshin I. V. Senkov V. M. Shashkov E. V. Fishman R. I. Ziyatdinova M. Z. Komel’kov A. S. 《JETP Letters》2020,112(11):734-738
JETP Letters - The possibility of stable generation of intense characteristic Cs radiation upon electronic excitation of a Mo anode target heat treated in Cs and O2 vapors is demonstrated. The... 相似文献
34.
Ieva
Dauickait Amos S. Lawless Jennifer A. Scott Peter Jan van Leeuwen 《Numerical Linear Algebra with Applications》2020,27(5)
We consider the large sparse symmetric linear systems of equations that arise in the solution of weak constraint four‐dimensional variational data assimilation, a method of high interest for numerical weather prediction. These systems can be written as saddle point systems with a 3 × 3 block structure but block eliminations can be performed to reduce them to saddle point systems with a 2 × 2 block structure, or further to symmetric positive definite systems. In this article, we analyse how sensitive the spectra of these matrices are to the number of observations of the underlying dynamical system. We also obtain bounds on the eigenvalues of the matrices. Numerical experiments are used to confirm the theoretical analysis and bounds. 相似文献
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Susana Estopiñá-Durán Liam J. Donnelly Euan B. Mclean Bryony M. Hockin Prof. Alexandra M. Z. Slawin Dr. James E. Taylor 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(15):3950-3956
A combination of pentafluorophenylboronic acid and oxalic acid catalyses the dehydrative substitution of benzylic alcohols with a second alcohol to form new C−O bonds. This method has been applied to the intermolecular substitution of benzylic alcohols to form symmetrical ethers, intramolecular cyclisations of diols to form aryl-substituted tetrahydrofuran and tetrahydropyran derivatives, and intermolecular crossed-etherification reactions between two different alcohols. Mechanistic control experiments have identified a potential catalytic intermediate formed between the aryl boronic acid and oxalic acid. 相似文献
37.
Peter T. Smith Younghoon Kim Dr. Bahiru Punja Benke Prof. Kimoon Kim Prof. Christopher J. Chang 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(12):4932-4937
We report a supramolecular strategy for promoting the selective reduction of O2 for direct electrosynthesis of H2O2. We utilized cobalt tetraphenylporphyrin (Co-TPP), an oxygen reduction reaction (ORR) catalyst with highly variable product selectivity, as a building block to assemble the permanently porous supramolecular cage Co-PB-1(6) bearing six Co-TPP subunits connected through twenty-four imine bonds. Reduction of these imine linkers to amines yields the more flexible cage Co-rPB-1(6). Both Co-PB-1(6) and Co-rPB-1(6) cages produce 90–100 % H2O2 from electrochemical ORR catalysis in neutral pH water, whereas the Co-TPP monomer gives a 50 % mixture of H2O2 and H2O. Bimolecular pathways have been implicated in facilitating H2O formation, therefore, we attribute this high H2O2 selectivity to site isolation of the discrete molecular units in each supramolecule. The ability to control reaction selectivity in supramolecular structures beyond traditional host–guest interactions offers new opportunities for designing such architectures for a broader range of catalytic applications. 相似文献
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Nonlinear Dynamics - We generalize previously obtained solutions to the generalized nonlinear Schrödinger equation (NLSE) with cubic-quintic nonlinearity and distributed coefficients to obtain... 相似文献
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Stadnyk V. Yo. Shchepanskyi P. A. Rudysh M. Ya. Kogut Z. A. 《Journal of Applied Spectroscopy》2021,88(4):831-837
Journal of Applied Spectroscopy - The temperature dependence of the refractive indices of K2SO4 with copper impurity was investigated. It was found that introduction of the copper impurity leads to... 相似文献