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311.
Laia Malet-Sanz Julia Madrzak Rhian S. Holvey Toby Underwood 《Tetrahedron letters》2009,50(52):7263-569
A method for the safe and reliable iododeamination of aromatic and heteroaromatic amines under copper-free conditions is described and its scope is evaluated. 相似文献
312.
Szmytkowski J Bond T Paige MF Scott RW Steer RP 《The journal of physical chemistry. A》2010,114(43):11471-11476
The steady-state absorption and emission spectra and the time-resolved Soret- and Q-band excited fluorescence profiles of the model metalloporphyrin, ZnTPP, have been measured in a highly purified sample of the common room temperature ionic liquid, [bmim][PF?]. S?-S? emission resulting from Soret-band excitation behaves in a manner completely consistent with that of molecular solvents of the same polarizability. The ionic nature of the solvent and its slow solvation relaxation times have no significant effect on the nature of the radiationless decay of the S? state, which decays quantitatively to S? at a population decay rate that is consistent with the weak coupling case of radiationless transition theory (energy gap law). The ratio of the intensities of the Qα:Qβ (0-0:1-0) bands is consistent with the solvatochromic shift correlation data obtained for molecular solvents. The temporal S? fluorescence decay profiles measured at a single emission wavelength are biexponential; the longer-lived major component is similar to that observed for ZnTPP in molecular solvents, and the minor shorter-lived component is attributed to solvent relaxation processes on a nanosecond time scale. 相似文献
313.
Dr. Stephanie A. Boer Dr. Keith F. White Benjamin Slater Adrian J. Emerson Dr. Gregory P. Knowles Dr. William A. Donald Dr. Aaron W. Thornton Prof. Bradley P. Ladewig Dr. Toby D. M. Bell Prof. Matthew R. Hill Prof. Alan L. Chaffee Prof. Brendan F. Abrahams Dr. David R. Turner 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(36):8489-8493
A chiral, octahedral M12L12 cage, which is charge neutral and contains an internal void of about 2000 Å3, is reported. The cage was synthesised as an enantiopure complex by virtue of amino-acid-based dicarboxylate ligands, which assemble around copper paddlewheels at the vertices of the octahedron. The cage persists in solution with retention of the fluorescence properties of the parent acid. The solid-state structure contains large pores both within and between the cages, and displays permanent porosity for the sorption of gases with retention of crystallinity. Initial tests show some enantioselectivity of the cage towards guests in solution. 相似文献
314.
315.
The order of magnitude method offers an alternative to the Chapman-Enskog and Grad methods to derive macroscopic transport
equations for rarefied gas flows. This method yields the regularized 13 moment equations (R13) and a generalization of Grad’s
13 moment equations for non-Maxwellian molecules. Both sets of equations are presented and discussed. Solutions of these systems
of equations are considered for steady state Couette flow. The order of magnitude method is used to further reduce the generalized
Grad equations to the non-linear bulk equations, which are of second order in the Knudsen number. Knudsen layers result from
the linearized R13 equations, which are of the third order. Superpositions of bulk solutions and Knudsen layers show good
agreement with DSMC calculations for Knudsen numbers up to 0.5.
相似文献
316.
317.
Carson Sievert Susan VanderPlas Jun Cai Kevin Ferris Faizan Uddin Fahad Khan Toby Dylan Hocking 《Journal of computational and graphical statistics》2019,28(2):299-308
Interactive web graphics are great for communication and knowledge sharing, but are difficult to leverage during the exploratory phase of a data science workflow. Even before the web, interactive graphics helped data analysts quickly gather insight from data, discover the unexpected, and develop better model diagnostics. Although web technologies make interactive graphics more accessible, they are not designed to fit inside an exploratory data analysis (EDA) workflow where rapid iteration between data manipulation, modeling, and visualization must occur. To better facilitate exploratory web graphics that are easily distributed, we need better interfaces between statistical computing environments (e.g., the R language) and client-side web technologies. We propose the R package animint for rapid creation of linked and animated web graphics through a simple extension of ggplot2’s implementation of the Grammar of Graphics. The extension allows one to write ggplot2 code and produce a standalone web page with multiple linked views. Supplementary material for this article is available online. 相似文献
318.
Toby Kenney 《Journal of Algebraic Combinatorics》2014,39(3):719-731
Associated with any Coxeter group is a Coxeter monoid, which has the same elements, and the same identity, but a different multiplication. (Some authors call these Coxeter monoids 0-Hecke monoids, because of their relation to the 0-Hecke algebras—the q=0 case of the Hecke algebra of a Coxeter group.) A Coxeter group is defined as a group having a particular presentation, but a pair of isomorphic groups could be obtained via non-isomorphic presentations of this form. We show that when we have both the group and the monoid structure, we can reconstruct the presentation uniquely up to isomorphism and present a characterisation of those finite group and monoid structures that occur as a Coxeter group and its corresponding Coxeter monoid. The Coxeter monoid structure is related to this Bruhat order. More precisely, multiplication in the Coxeter monoid corresponds to element-wise multiplication of principal downsets in the Bruhat order. Using this property and our characterisation of Coxeter groups among structures with a group and monoid operation, we derive a classification of Coxeter groups among all groups admitting a partial order. 相似文献