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41.
42.
The internal field patterns for gold shells filled with the same material as the surrounding medium are calculated with Mie theory and in the quasistatic approximation and their properties compared to the response of homogeneous spheres and metallic rings. One major difference between the sphere and shell case is that the areas of highest field enhancement in metallic shells are located perpendicular to the incident polarization, whereas for metallic spheres they are along the polarization direction. Recent results based on the discrete dipole approximation (DDA) are shown to be misleading, which might be due to the use of a too coarse grid size. We also show that the type of resonance and the associated internal field pattern (low or high energy) has a strong impact on the external fields. 相似文献
43.
Similarities in properties among pairs of metallic elements and their compounds in the lower-right quadrant of the Periodic
Table have been named the ‘Knight’s Move’ relationship. Here, we have undertaken a systematic study of the only two ‘double-pairs’
of ‘Knight’s Move’ elements within this region: copper-indium/indium-bismuth and zinc-tin/tin-polonium, focussing on: metal
melting points; formulas and properties of compounds; and melting points of halides and chalcogenides. On the basis of these
comparisons, we conclude that the systematic evidence for ‘Knight’s Move’ relationships derives from similarities in formulas
and properties of matching pairs of compounds in the same oxidation state. Physical properties, such as melting points, do
not provide consistent patterns and trends and hence should not be considered as a common characteristic of this relationship. 相似文献
44.
Galyna Shul Maria A. Murphy Geoff D. Wilcox Frank Marken Marcin Opallo 《Journal of Solid State Electrochemistry》2005,9(12):874-881
Composite electrodes were prepared from chemical vapor deposition grown carbon nanofibers consisting predominantly of ca.
100 nm diameter fibers. A hydrophobic sol–gel matrix based on a methyl-trimethoxysilane precursor was employed and composites
formed with carbon nanofiber or carbon nanofiber—carbon particle mixtures (carbon ceramic electrode). Scanning electron microscopy
images and electrochemical measurements show that the composite materials exhibit high surface area with some degree of electrolyte
solution penetration into the electrode. These electrodes were modified with redox probe solution in 2-nitrophenyloctylether.
A second type of composite electrode was prepared by simple pasting of carbon nanofibers and the same solution (carbon paste
electrode). For both types of electrodes it is shown that high surface area carbon nanofibers dominate the electrode process
and enhance voltammetric currents for the transfer of anions at liquid|liquid phase boundaries presumably by extending the
triple-phase boundary. Both anion insertion and cation expulsion processes were observed driven by the electro-oxidation of
decamethylferrocene within the organic phase. A stronger current response is observed for the more hydrophobic anions like
ClO4− or PF6− when compared to that for the more hydrophilic anions like F− and SO42−.
Presented at the 4th Baltic Conference on Electrochemistry, Greifswald, March 13–16, 2005 相似文献
45.
Micellar electrokinetic capillary chromatography has been explored as an efficient and rapid method of separating the photoproducts of 2′-deoxyuridylyl-(3′-5′)-thymidine (i.e., cis-syn and trans-syn cyclobutane dimers, (6–4) photoproduct, and the related Dewar valence isomer) from normal nucleosides and nucleotides. Three cationic surfactants, dodecyl-, tetradecyl-, and hexadecyltrimethy-lammonium bromide were evaluated and the separations compared with those obtainable with the anionic surfactant, sodium dodecylsulfate. Optimum resolution of the dinucleoside monophosphate photoproducts was obtained using tetradecyltrimethylammonium bromide. By use of this detergent the photoproducts could also be separated from other normal constituents in less than 6 min at ?25 kV. Dodecyl- and hexadecyltrimethylammonium bromide provided some separation between the various species but sodium dodecylsulfate did not separate the UV radiation-induced products from either the parent compound or other dinucleoside monophosphates. Increased interaction between negatively charged solutes and positively charged micelles accounts for the differences. 相似文献
46.
Demeter Krupka Olga Krupková Geoff Prince 《Differential Geometry and its Applications》2007,25(5):518-542
In this paper, vector fields which are symmetries of the contact ideal are studied. It is shown that contact symmetries of the Helmholtz form transform a dynamical form to a dynamical form which is variational (i.e. comes as the Euler-Lagrange form from a Lagrangian). The case of dynamical forms representing first-order classes in the variational sequence is analysed in detail, which means, by the variational sequence theory, that systems of ordinary differential equations of order ?3 are concerned. 相似文献
47.
R.Geoff Dromey 《Analytica chimica acta》1979,112(2):133-141
A scaling procedure that minimizes effects caused by mass discrimination-and other instrumental distortion in computer-matching of mass spectra is described. It is shown how spectra should be matched only when they have been scaled to be at their minimum “distance” with respect to the similarity index in use for the measurement. 相似文献
48.
The depolarised light scattering spectra of liquid pyridine allow us to confirm the attribution of rotational diffusion constants proposed by Kintzinger and Lehn. We also observe the presence of collective modes. 相似文献
49.
50.