排序方式: 共有93条查询结果,搜索用时 15 毫秒
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Cozzoli PD Comparelli R Fanizza E Curri ML Agostiano A Laub D 《Journal of the American Chemical Society》2004,126(12):3868-3879
A novel colloidal approach toward semiconductor/metal nanocomposites is presented. Organic-soluble anatase TiO(2) nanorods are used for the first time to stabilize Ag nanoparticles in optically clear nonpolar solutions in the absence of specific ligands for silver. Metallic silver is generated upon UV illumination of deaerated TiO(2) solutions containing AgNO(3). The Ag nanoparticles can be obtained in different size-morphological regimes as a function of the irradiation time, due to light-induced photofragmentation and ripening processes. A mechanism for the colloidal stabilization of the silver nanoparticles is tentatively suggested, which regards the TiO(2) nanorods as inorganic stabilizers, thus acting in the same manner as conventional surfactant molecules. The proposed photocatalytic approach offers a convenient method for producing TiO(2)/Ag nanocomposite systems with a certain control over the metal particle size without the use of surfactants and/or additives. Stable colloidal TiO(2)-nanorod-stabilized Ag nanoparticles can be potentially available for a number of applications that require "clean" metal surfaces, such as homogeneous organic catalysis, photocatalysis, and sensing devices. 相似文献
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Zusammenfassung Es kann gezeigt werden, daß sich im Außenhandelsmodell vonMorgenstern/ Thompson gewisse Aussagen nicht unbedingt als Resultate aus dem vorgeschlagenen Axiomensystem ergeben. Werden diese Aussagen in das Axiomensystem aufgenommen, so bleibt das System unabhängig.
Summary In the Open Expanding Economy Model ofMorgenstern/Thompson it can be shown that some of the statements do not follow from the axioms. Adding these statements to the given system of axioms the new system is still independent.相似文献
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Petrella A Cozzoli PD Curri ML Striccoli M Cosma P Agostiano A 《Bioelectrochemistry (Amsterdam, Netherlands)》2004,63(1-2):99-102
Hetero-structures formed by quantum-sized ZnO nanocrystals and photosynthetic pigments were prepared by adsorbing either chlorophyll a, carotenoids or their mixture onto a film of organic-capped ZnO nanoparticles. Photoelectrochemical measurements were comparatively performed on both bulk and nanocrystalline ZnO films after dye-covering in order to probe the photosensitization process occurring at the hetero-junction. The photoconversion process was found to be greatly enhanced at the nanocrystalline electrodes upon sensitization with a dye mixture. The sensitization process is discussed on the basis of the aggregation state of chlorophyll a, and of the specific photoprotective action played by carotenoids. 相似文献
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Frontispiece: Electrochemiluminescence Bioassays with a Water‐Soluble Luminol Derivative Can Outperform Fluorescence Assays 下载免费PDF全文
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Changes of the refractive index for homologous series of hydrocarbons are usually plotted versus the density. While there is a clear linear dependence for alkanes and alkenes, the linearity deteriorates for homologous series with functional groups involving heteroatoms. The slope can even become negative, e. g., for carboxylic acids. For gaining a deeper understanding and to establish a more general correlation, we reinvestigate the corresponding theories starting with the Newton-Laplace, Gladstone-Dale and the Lorentz-Lorenz rules. We revisit the concept of molar refractivity pioneered by Landolt and Brühl and show that it is closely connected with a twin of Beer's law. We conclude that the refractive index of homologues series should better be plotted versus the molar concentration of the main UV-chromophore, the C−H bond, which actually causes the refractive index changes. This new approach is not limited to alkanes and alkenes but holds for homologous series with functional groups including heteroatoms. 相似文献
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Prof. Dr. Bikshandarkoil R. Srinivasan Santosh Y. Shetgaonkar PD Dr. Christian Näther 《无机化学与普通化学杂志》2011,637(1):130-136
The preparation, crystal structures, and thermal properties of [Ca(pyr)2(4‐nba)2]n ( 1 ) (pyr = pyrazole; 4‐nba = 4‐nitrobenzoate) {[Ca(H2O)2(3‐npth)] · H2O}n ( 2 ) (3‐npth = 3‐nitrophthalate), [Mg(H2O)5(3‐npth)] · 2H2O ( 3 ), and [Mg(H2O)4(2‐nba)2] ( 4 ) (2‐nba = 2‐nitrobenzoate) are reported. The anhydrous CaII compound 1 and the diaqua CaII‐3‐nitrophthalate monohydrate 2 are one‐dimensional coordination polymers containing a hexacoordinate CaII ion located on a center of inversion in 1 and a heptacoordinated CaII ion in 2 . In 1 , the 4‐nitrobenzoate moiety acts as a μ2‐bridging bidentate ligand, whereas the 3‐nitrophthalate anion exhibits a μ3‐bridging pentadentate coordination mode in 2 . The hexacoordinate MgII‐containing compounds 3 and 4 do not contain a [Mg(H2O)6]2+ unit and the central MgII ion is coordinated to at least one monodentate carboxylate unit namely the monodentate 3‐npth molecule in 3 and two trans monodentate 2‐nba molecules in 4 . Hydrogen bonding between the lattice water molecules results in the formation of a water dimer in 3 . A comparative study of 17 alkaline earth nitrocarboxylates is described. 相似文献
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