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Uses of the numerical radius in the analysis of basic iterative solution methods, of the SOR method for quasi-Hermitian positive definite matrices (not being consistently ordered) and of maximal eigenvalues of symmetric positive definite matrices using incomplete block-matrix factorizations are presented. 相似文献
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Bernd M. Rode Michael G. Schwendinger Sirirat U. Kokpol Supot V. Hannongbua Supa Polman 《Monatshefte für Chemie / Chemical Monthly》1989,120(11):913-921
Summary Linear models for the relation between electronic structure and antimalarial activity of chloroquine drugs have been investigated, based on CNDO/2 molecular orbital calculations. The results indicate that changes in electron density on the atoms N1, N2, C4, C9, and C10 have the strongest influence on the pharmacological activity, so that these atoms can be assumed to form the main active center of these drugs. Correlations improve, if substitution on the nucleus of chloroquine and side chain variations are treated separately. The models found seem to be a useful tool for designing new drugs within the chloroquine series.
Quantenchemisch-pharmakologische Untersuchungen von Antimalaria-Wirkstoffen
Zusammenfassung Auf der Basis von CNDO/2-Rechnungen wurden lineare Modelle für die Relation zwischen Elektronenverteilung und der Antimalaria-Aktivität von Chlorochinen untersucht. Es zeigte sich, daß Veränderungen in den Elektronendichten der Atome N1, N2, C4, C9 und C10 den stärksten Einfluß auf die pharmakologische Wirkung haben. Es kann somit angenommen werden, daß diese Atome die hauptsächlich aktiven Zentren der Verbindung sind. Die Korrelation wird verbessert, wenn die Substitution am Chlorochin-Kern und Variationen der Seitenketten separat behandelt werden. Die aufgefundenen Modellvorstellungen sollten ein nützliches Werkzeug zur gezielten Synthese neuer Wirkstoffe innerhalb der Chlorochin-Reihe darstellen.相似文献
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S. Coffa S. Lombardo F. Priolo G. Franzó S. U. Campisano A. Polman G. N. van den Hoven 《Il Nuovo Cimento D》1996,18(10):1131-1148
Summary In this work we demonstrate that efficient light emission at 1.54 μm can be achieved when Er ions are incorporated into crystalline
Si or in heavily oxygen-doped amorphous and polycrystalline Si films (SIPOS). We have found that temperature quenching of
photo- and electroluminescence, which is the major limitation towards the achievement of room temperature luminescence, can
be strongly reduced by codoping these films with oxygen. This impurity is already present in as-prepared SIPOS and it is introduced
by ion-implantation in crystalline Si. Er luminescence is obtained under both optical and electrical excitation and we demonstrate
that excitation occurs through a carrier-mediated process. Electrical excitation is obtained by incorporating Er in properly
designed device structures. It is found that this excitation can occur both through the recombination of hole-electron pairs
and through impact excitation of the Er ions by hot electrons. These two mechanisms have different efficiencies and impact
excitation is shown to prevail at room temperature. These data are presented and possible future developments are discussed.
Paper presented at the III INSEL (Incontro Nazionale sul Silicio Emettitore di Luce), Torino, 12–13 October 1995. 相似文献
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A van der Horst P N de Goede H A van Diemen C H Polman H J Martens 《Journal of chromatography. A》1992,574(1):166-169
An assay for the determination of 4-aminopyridine in serum has been developed using 3,4-diaminopyridine as internal standard and reversed-phase high-performance liquid chromatography with detection at 244 nm. A mobile phase of acetonitrile-methanol-ethanol-1% ammonium carbonate (75:10:10:5) provided excellent separation of both compounds. Samples were extracted on solid-phase columns. The linearity, precision, recovery and the limit of detection were all sufficient for the routine use of this assay in clinical studies of patients treated with 4-aminopyridine. 相似文献
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Polman James K. Breckenridge Cynthia R. Dugan Patrick R. Quigley David R. 《Applied biochemistry and biotechnology》1991,(1):487-494
Applied Biochemistry and Biotechnology - 相似文献
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Grimminck DL Polman BJ Kentgens AP Meerts WL 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2011,211(2):114-120
A fast and accurate fit program is presented for deconvolution of one-dimensional solid-state quadrupolar NMR spectra of powdered materials. Computational costs of the synthesis of theoretical spectra are reduced by the use of libraries containing simulated time/frequency domain data. These libraries are calculated once and with the use of second-party simulation software readily available in the NMR community, to ensure a maximum flexibility and accuracy with respect to experimental conditions. EASY-GOING deconvolution (EGdeconv) is equipped with evolutionary algorithms that provide robust many-parameter fitting and offers efficient parallellised computing. The program supports quantification of relative chemical site abundances and (dis)order in the solid-state by incorporation of (extended) Czjzek and order parameter models. To illustrate EGdeconv's current capabilities, we provide three case studies. Given the program's simple concept it allows a straightforward extension to include other NMR interactions. The program is available as is for 64-bit Linux operating systems. 相似文献
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Polman J. Kevin Rae Catherine Delezene-Briggs Karen M. 《Applied biochemistry and biotechnology》1996,57(1):327-338
Applied Biochemistry and Biotechnology - Inclusion of coal inSaccharomyces cerevisiae cultures enhanced ethanol and biomass production (from dextrose) similarly to yeast extract. Coal-induced... 相似文献
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Applied Biochemistry and Biotechnology - 相似文献