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41.
An alternating direction scheme on a nonuniform mesh for reaction-diffusion parabolic problems 总被引:1,自引:0,他引:1
Clavero C; Jorge JC; Lisbona F; Shishkin={paragraph} GI 《IMA Journal of Numerical Analysis》2000,20(2):263-280
In this paper we develop a numerical method for two-dimensionaltime-dependent reaction-diffusion problems. This method, whichcan immediately be generalized to higher dimensions, is shownto be uniformly convergent with respect to the diffusion problems.This method, which can immediately be generalized to higherdimensions, is shown to be uniformly convergent with respectto the diffusion parameter. 相似文献
42.
Hsi WC Kunde GJ Pochodzalla J Lynch WG Tsang MB Begemann-Blaich ML Bowman DR Charity RJ Cosmo F Ferrero A Gelbke CK Glasmacher T Hofmann T Imme G Iori I Hubele J Kempter J Kreutz P Kunze WD Lindenstruth V Lisa MA Lynen U Mang M Moroni A Müller WF Neumann M Ocker B Ogilvie CA Peaslee GF Raciti G Rosenberger F Sann H Scardaoni R Schüttauf A Schwarz C Seidel W Serfling V Sobotka LG Stuttge L Tomasevic S Trautmann W Tucholski A Williams C Wörner A Zwieglinski B 《Physical review letters》1994,73(25):3367-3370
43.
Evidence for demethylation of syringyl moieties in archaeological wood using pyrolysis-gas chromatography/mass spectrometry 总被引:1,自引:0,他引:1
van Bergen PF Poole I Ogilvie TM Caple C Evershed RP 《Rapid communications in mass spectrometry : RCM》2000,14(2):71-79
Archaeological oak (Quercus sp.) wood samples, ranging from 16(th) C. AD to 6000 BP, were studied using flash pyrolysis-gas chromatography/mass spectrometry to obtain insight into angiosperm lignin degradation. The pyrolysates revealed evidence of a number of 3-methoxy-1,2-benzenediol derivatives, methoxycatechols, directly related to 2,6-dimethoxyphenol, syringyl, moieties which are characteristic building blocks of angiosperm lignin. Mass spectra and mass chromatograms of these compounds are reported. The finding of these characteristic pyrolysis products in well-preserved archaeological wood provides unequivocal evidence that demethylation of syringyl units occurs very early in wood degradation. It is highly likely that the absence of abundant 3-methoxy-1, 2-benzenediols in degrading plant materials containing angiosperm lignin relates to the lability of these newly formed moieties. 相似文献
44.
Y Guindon F Soucy C Yoakim W W Ogilvie L Plamondon 《The Journal of organic chemistry》2001,66(26):8992-8996
The work described herein considers the impact of stereoelectronic effects and allylic 1,3-strain in controlling the cyclofunctionalization reaction when a hydroxyl group is at the allylic position. The stereoelectronic arguments are supported by independent iodocyclization reactions performed using two secondary alcohols. The transition-state pathways involved in these reactions are established through a comparison of relative reaction rates. A bi-directional approach is used to demonstrate the potential of the iodocyclization reaction to differentiate a terminus in molecules with a pseudo C(2) axis of symmetry, showing that two-directional synthesis can be used to differentiate between alternative transition-state pathways. 相似文献
45.
Kelvin K. Ogilvie Gholam H. Hakimelahi Zbigniew A. Proba Danny P.C. McGee 《Tetrahedron letters》1982,23(19):1997-2000
Procedure have been developed which allow for the selective derivatization of arabinonucleosides at the 5′? or 2′? and 5′? or 3′? and 5′? positions. 相似文献
46.
J.F. Ogilvie 《Journal of Molecular Structure》1976,31(2):407-410
New structural parameters have been deduced for the ground electronic states for formyl and hydroperoxyl radicals and nitrosyl hydride, from experimental rotational constants. The values obtained are consistent with known vibrational data and bond dissociation energies. 相似文献
47.
48.
The synthesis of compounds having a phosphite bridge between nucleoside units, their characteristics toward phosphodiesterases, their conversion to normal nucleotides and their use in oligonucleotide synthesis is described. 相似文献
49.
James R. Hitchin Niall M. Hamilton Allan M. Jordan Amanda J. Lyons Donald J. Ogilvie 《Tetrahedron letters》2012,53(23):2868-2872
A novel scalable stereoselective synthesis of 3α- and 3β-amino-5α-androstan-17-ones and 3α- and 3β-amino-5α-pregnan-20-ones has been developed using phthalimide based Mitsunobu chemistry. In all four cases, the products were isolated as single diastereoisomers in high chemical yield and purity without the need for chromatography at any stage in their syntheses. 相似文献
50.
Theoretical expressions for the Herman-Wallis factors in terms of the Dunham potential-energy parameters and dipole-moment coefficients were derived for higher overtone bands by the method of computer algebra. These results were applied to an analysis of the vibration-rotational intensities of HCl, leading to a good fit of the data and a dipole-moment function that is improved and extended by comparison with previous results. 相似文献