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411.
Bauer DA Belcinski R Berg RC Bingham HH Bloom ED Buchanan CD Caldwell DO Chun SB Clark AR Dahl OI Eastman JJ Eberhard PH Eisner AM Fairfield KH Godfrey G Greenbaum GS Hauptman JM Hofmann W Holtzapple RL Khacheryan S Knöpfle KT Kofler RR Lambert DJ Loken SC Lu A Lynch GR Lys JE Madaras RJ Marsiske H Masek GE Miller ES Nicol NA Nygren DR Oyang YT Paar HP Palounek AP Pellett DE Ronan MT Ross RR Shapiro G Stephens RW Stevenson ML Strauss MG Sullivan MK Vernon W Wang EM Wang YX Wenzel WA Yamamoto H 《Physical review D: Particles and fields》1994,50(1):R13-R17
412.
R. A. Phillips J. Castles Stevenson M. R. Nagarajan S. L. Cooper 《Journal of Macromolecular Science: Physics》2013,52(2-3):245-274
The structure-property relationships of polyurethane elastomers based on 4,4′-diphenylmethane diisocyanate (MDI) and 4,4′-dicyclohexylmethane diisocyanate (HMDI) with PTMO, PDMS, and mixed PTMO/PDMS soft segments were investigated using DSC, dynamic mechanical spectroscopy, tensile testing, and SAXS. Changes in water absorption and moisture sensitivity with compositional changes were investigated through water absorption and physical property measurements. Differences in tensile properties and moisture sensitivity with varying hard and soft segment composition are interpreted in terms of the phase mixing characteristics of the various polymers studied. 相似文献
413.
Rob P. Stevenson 《Numerische Mathematik》2005,101(2):355-379
Although adaptive finite element methods for solving elliptic problems often work well in practice, they are usually not proven to converge. For Poisson like problems, an exception is given by the method of Dörfler ([8]), that was later improved by Morin, Nochetto and Siebert ([11]). In this paper we extend these methods by constructing an adaptive finite element method for a singularly perturbed reaction-diffusion equation that, in energy norm, converges uniformly in the size of the reaction term. Moreover, in this algorithm the arising Galerkin systems are solved only inexactly, so that, generally, the number of arithmetic operations is equivalent to the number of triangles in the final partition.This work was supported by the Netherlands Organization for Scientific Research and by the EU-IHP project “Breaking Complexity.” 相似文献
414.
Isolation of CeLu2N@Ih‐C80 through a Non‐Chromatographic,Two‐Step Chemical Process and Crystallographic Characterization of the Pyramidalized CeLu2N within the Icosahedral Cage
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Prof. Dr. Steven Stevenson Hannah R. Thompson Kristine D. Arvola Kamran B. Ghiassi Prof. Dr. Marilyn M. Olmstead Prof. Dr. Alan L. Balch 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(29):10362-10368
By combining two chemical methods of purification, 4 mg of purified CeLu2N@C80 was readily isolated from 500 mg of carbon soot extract without the use of recycling HPLC, a method which has previously been necessary to obtain pure samples of endohedral fullerenes. In stage 1, CeLu2N@C80 was selectively precipitated by virtue of its low first oxidation potential (+0.01 V) and the judicious choice of MgCl2 as the Lewis acid precipitant. For stage 2, we used a stir and filter approach (SAFA), which employed the electron‐rich NH2 groups immobilized on silica gel to selectively bind residual endohedrals and higher cage fullerenes that were contaminants from stage 1. Crystallographic analysis of CeLu2N@C80 in the co‐crystal CeLu2N@Ih‐C80 ? Ni(octaethylporphyrin) ? 2(toluene) reveals that the Ih‐C80 cage is present with a pyramidalized CeLu2N unit inside. 相似文献
415.
Screening of cannabinoids in industrial‐grade hemp using two‐dimensional liquid chromatography coupled with acidic potassium permanganate chemiluminescence detection
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Jessica Pandohee Brendan J. Holland Bingshan Li Takuya Tsuzuki Paul G. Stevenson Neil W. Barnett James R. Pearson Oliver A.H. Jones Xavier A. Conlan 《Journal of separation science》2015,38(12):2024-2032
Widely known for its recreational use, the cannabis plant also has the potential to act as an antibacterial agent in the medicinal field. The analysis of cannabis plants/products in both pharmacological and forensic studies often requires the separation of compounds of interest and/or accurate identification of the whole cannabinoid profile. In order to provide a complete separation and detection of cannabinoids, a new two‐dimensional liquid chromatography method has been developed using acidic potassium permanganate chemiluminescence detection, which has been shown to be selective for cannabinoids. This was carried out using a Luna 100 Å CN column and a Poroshell 120 EC‐C18 column in the first and second dimensions, respectively. The method has utilized a large amount of the available separation space with a spreading angle of 48.4° and a correlation of 0.66 allowing the determination of more than 120 constituents and mass spectral identification of ten cannabinoids in a single analytical run. The method has the potential to improve research involved in the characterization of sensitive, complex matrices. 相似文献
416.
Susan M. Stevenson Prof. Dr. Matthew P. Shores Prof. Dr. Eric M. Ferreira 《Angewandte Chemie (International ed. in English)》2015,54(22):6506-6510
The photooxidizing capabilities of selected CrIII complexes for promoting radical cation cycloadditions are described. These complexes have sufficiently long‐lived excited states to oxidize electron‐rich alkenes, thereby initiating [4+2] processes. These metal species augment the spectrum of catalysts explored in photoredox systems, as they feature unique properties that can result in differential reactivity from the more commonly employed ruthenium or iridium catalysts. 相似文献
417.
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420.
Rajiv T. Sawant Joanne Stevenson Luke R. Odell Per I. Arvidsson 《Tetrahedron: Asymmetry》2013,24(2-3):134-141
Herein we report a facile organocatalytic asymmetric direct cross-aldol reaction of 2-chloroethoxy acetaldehyde with aromatic aldehydes using (S)-(?)-α,α-diphenyl-2-pyrrolidinemethanol as an organocatalyst to afford anti-2-(2-chloroethoxy)-1-arylpropane-1,3-diols with excellent enantioselectivities (95–98%) and moderate diastereoselectivities (3.5–7:1). The 1,3-diols, obtained after the aldehyde reduction, represent highly functional intermediates that allow for further diversification into both chiral 1,4-dioxanes and morpholines, compounds that frequently display interesting biological activities. 相似文献