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  • 1
    Digitale Medien
    Digitale Medien
    Dynamics of surface-aligned photochemistry (theory). II. Localized H-atom scattering in the HBr(ad)/LiF(001)+hν system (1992)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 97 (1992), S. 9458-9467 
    Details
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: The angular and energy distributions of 1.1 and 2.6 eV H-atom scattering from a LiF(001) surface are compared for two different sources of hot H-atoms (1) localized H-atoms produced by the photolysis of HBr molecules adsorbed on the LiF surface; and (2) H-atoms from a beam at the same energy and angle of approach to the LiF surface as in (1). These distributions are the results of classical stochastic trajectories carried out on a 7×7 slab of LiF(001). The calculated angular distributions are compared with experimental distributions [E. B. D. Bourdon et al., J. Chem. Phys. 95, 1361 (1991)]. The computed effects of changing H-atom energy and surface temperature are also reported; localized scattering becomes increasingly nonspecular at lower photon energies, and broader at higher surface temperatures.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.463967
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  • 2
    Digitale Medien
    Digitale Medien
    Dynamics of surface-aligned photochemistry (Theory). IV. Hydrogen atom reactions in the hydrogen bromide(ad)/lithium fluoride(001) + h.nu. system (1993)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 97 (1993), S. 12541-12552 
    Details
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie , Physik
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1021/j100150a016
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  • 3
    Digitale Medien
    Digitale Medien
    Structures and stability of CO layers on the MgO(001) surface (2000)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 112 (2000), S. 5133-5143 
    Details
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: Monte Carlo simulations of CO/MgO(001) show that below 41 K the CO molecules form a c(4×2) structure with six molecules per unit cell distributed into two kinds of adsorption sites: a perpendicular site and a tilted site (polar angle of 31°). Both sites are localized near Mg2+ ions. The occupancy of perpendicular sites to tilted sites occurs in the ratio of 1:2. At 41 K the c(4×2) phase undergoes a phase transition into a less dense, disordered phase accompanied by the expulsion of some molecules to form a partial second layer. The density of the remaining disordered layer is the same as for a p(3×2) phase and portions of the disordered layer show regions of short range ordering with either the c(4×2) or p(3×2) structures. The p(3×2) phase contains four molecules per unit cell and also consists of perpendicular and tilted sites, but in the ratio of 1:1. This structure was found to be stable up to 50 K after which the expulsion of some molecules and disordering of the layer occurred. A model to test the relative stability of these two phases by examining the difference in Gibbs free energy is constructed and shows that below 41 K the c(4×2) phase is the most stable but above 41 K the p(3×2) phase is the most stable. However, at low pressures the model suggests that the p(3×2) phase will not be observed and the layer will instead transform from the c(4×2) phase to a disordered phase at 41 K. This result reconciles the findings of low-energy electron diffraction (LEED) experiments [p(3×2) phase observed] with those of helium atom scattering (HAS) and polarization infrared spectroscopy (PIRS) experiments (disordered phase observed). It is proposed that the c(4×2)→p(3×2) transition is part of an infinite sequence of transitions involving (n×2)-type structures which, under suitable conditions of temperature and pressure, constitutes an example of the devil's staircase phenomenon. Such a phenomenon has been suggested by previous LEED experiments. © 2000 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.481070
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  • 4
    Digitale Medien
    Digitale Medien
    An order–disorder phase transition in monolayer CO/LiF(001) (1998)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 108 (1998), S. 5653-5656 
    Details
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: Monte Carlo simulations of CO physisorbed on a LiF(001) surface show that a monolayer of CO molecules forms an ordered p(2(square root of 2)×(square root of 2))R45 herringbone structure which undergoes an order–disorder phase transition around 30 K. The CO molecules sit near the Li+ sites (C atom down) with a tilt of ∼40° from the surface normal. © 1998 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.475974
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  • 5
    Digitale Medien
    Digitale Medien
    The monolayer and multilayer structure of CO2/NaCl(001) (1997)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 106 (1997), S. 2547-2550 
    Details
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: Results of a Monte Carlo simulation of monolayer and multilayers of CO2 molecules adsorbed on the (001) surface of NaCl at temperature T=55 K are presented. It is found that the monolayer adopts a (2×1) structure; bilayers adopt either a (2×1) or a c(2×2) structure with the latter configuration energetically favored; and trilayers adopt a c(2×2) structure owing to the instability of the (2×1) structure. These results are in accord with recent helium scattering work.© 1997 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.473159
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  • 6
    Digitale Medien
    Digitale Medien
    A simulation of the phase transition in monolayer CO/NaCl(001) (1997)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 106 (1997), S. 2551-2554 
    Details
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: We report a Monte Carlo simulation of the p(2×1)→p(1×1) phase transition in a monolayer of CO molecules adsorbed on a NaCl(001) surface. In the p(2×1) phase the CO molecules are tilted by 24° from the surface normal and have preferred azimuthal orientations whereas in the p(1×1) phase the molecules are oriented perpendicular to the surface with no preferred azimuthal orientation. The transition temperature is estimated to lie in the range 30–35 K. Multiple domains and phase coexistence are also observed.© 1997 American Institute of Physics.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.473349
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  • 7
    Digitale Medien
    Digitale Medien
    The effects of ranitidine and cimetidine on the pharmacokinetics and pharmacodynamics of metoprolol (1988)
    Oxford, UK : Blackwell Publishing Ltd
    Alimentary pharmacology & therapeutics 2 (1988), S. 0 
    Details
    ISSN: 1365-2036
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: The impact of cimetidine, ranitidine and placebo on the pharmacokinetics of metoprolol, given either as a single dose (100 mg) or for 7 days (100 mg b.d.), has been evaluated in two separate studies. The doses used were 800 mg cimetidine daily and 300 mg ranitidine daily. The subjects were all young, healthy volunteers. In the single dose study, cimetidine produced a marked increase in the peak plasma concentration of metoprolol and in the area under the plasma concentration-time curve; ranitidine had less effect, though the area under the curve was significantly greater than placebo. In the chronic dosing study, the area under the curve for metoprolol was also significantly higher on cimetidine (1796 ng h/ml; P 〈 0.001) whereas the area under the curve on ranitidine (1258 ng h/ml) was comparable to that on placebo (1183 ng h/ml). Despite these drug-induced changes in plasma metoprolol concentration, neither cimetidine nor ranitidine altered the change in exercise-induced heart rate during dosing with metoprolol.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1111/j.1365-2036.1988.tb00726.x
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  • 8
    Digitale Medien
    Digitale Medien
    A good read (1981)
    [s.l.] : Nature Publishing Group
    Nature 293 (1981), S. 602-602 
    Details
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] SIR - That science is more complex that it was fifty years ago is reflected in the fragmentation of subjects into more and more specialities, each requiring at least one journal of its own to lend an air of respectability. The hard-pressed scientist wishing to keep a tenuous grasp on the broad ...
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1038/293602d0
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  • 9
    Digitale Medien
    Digitale Medien
    Twelve hour (trough) plasma nifedipine concentrations during chronic treatment with nifedipine retard (1987)
    Springer
    European journal of clinical pharmacology 32 (1987), S. 347-349 
    Details
    ISSN: 1432-1041
    Schlagwort(e): nifedipine ; plasma concentrations ; distribution ; debrisoquine phenotype ; retard preparation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Variations in plasma nifedipine concentrations have been reported and one study has suggested the existence of a subpopulation of poor metabolisers of this drug. We have studied the variability of 12 h plasma nifedipine concentrations in 64 hypertensive patients on long-term nifedipine Retard 20 mg twice daily. A slightly skewed unimodal distribution with a modal concentration of 15 to 30 ng/ml was obtained. No relationship between 12-h plasma levels and debrisoquine hydroxylation phenotype was found.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00543967
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  • 10
    Digitale Medien
    Digitale Medien
    The influence of food on the absorption of diclofenac as determined by the urinary excretion of the unchanged drug and its major metabolites during chronic administration (1981)
    Springer
    European journal of clinical pharmacology 19 (1981), S. 39-44 
    Details
    ISSN: 1432-1041
    Schlagwort(e): diclofenac ; metabolites ; urinary excretion ; food ; absorption ; chronic administration
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary Six healthy subjects took diclofenac as an enteric-coated preparation twice daily for 17 days under the following conditions: (i) fasting, (ii) 15 min before a meal, and (iii) immediately after a meal. Urine specimens were collected on two separate days of each regimen and diclofenac and its total monohydroxylated metabolites measured. Statistical analysis of the excretion of diclofenac and its metabolites showed that, during chronic administration, absorption was not significantly influenced by dosing before or after food. The absorption pattern after both these modes of administration was comparable to that obtained under fasting conditions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00558382
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