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11.
12.
The transport properties of a single-wall ZnO nanotube contacted with two Au (Al or Cu ) electrodes are investigated by a theoretical approach. Our results suggest the contact resistance for ZnO nanotube connected with Au electrodes is the largest one as compared with Al and Cu acting as electrodes. The local density of states (LDOS) near the ZnO nanotube/Cu(Al) interface shows the strong electronic interaction. Also shown is that for Au–ZnO system, we can observe a best rectifying performance, the next is the Al–ZnO system, and the third is Cu–ZnO system. This rectification is also fully rationalized by the calculated transmission spectra, the spatial distribution of the lowest unoccupied molecular orbital and highest occupied molecular orbital states, and the electrostatic potential distribution. 相似文献
13.
An ESR study has been made on the course of grafting of tetrafluoroethylene onto polyethylene. Alkyl and allyl radicals trapped in the polymers were measured under various grafting conditions. It was observed that alkyl radicals decay very rapidly when monomers are in contact with the irradiated polymer, while allyl radicals decay very slowly even in the presence of monomers as in the decay of radicals in irradiated polymers without monomers. The effect of pre-irradiation temperature on grafting was also studied, and the rate of grafting was found to be much faster for lower pre-irradiation temperatures. From these experimental results it was concluded that alkyl radicals play an important Tole in the initiation reaction of grafting. 相似文献
14.
Paula Gomes Maria João Araújo Eduardo F. Marques Soraia Falcão Rodrigo O. Brito 《合成通讯》2013,43(12):2025-2036
Double-chained surfactants with potential biocompatibility have been prepared in high yields by lysine acylation with four natural saturated fatty acids (C6 to C12) and with cis-undec-5-enoic acid. The surfactants were found to assemble into nanotubules in aqueous medium and, when mixed with a commercial cationic surfactant, to spontaneously form liposomes. 相似文献
15.
A silver-catalyzed reaction of 2-alkynylbenzaldoxime with arylsulfonyl chloride proceeds smoothly at room temperature to afford 4-tosyloxyisoquinolines in moderate to good yields. Additionally, the resulting 4-tosyloxyisoquinolines could be further elaborated through palladium-catalyzed coupling reactions leading to diverse isoquinolines. 相似文献
16.
Graphene (G) supported Pd–Co bimetallic nanoparticles (NPs) as a highly active catalyst was prepared by a chemical reduction method and used for coupling reactions. With the characterization of X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and Raman spectrum, the composition of resulting Pd–Co material was identified to be alloy structural. The Pd–Co (1:1)/G exhibited the highest catalytic activity for the Sonogashira-type coupling reactions and also exerted satisfied catalytic activity and recycle stability for Suzuki–Miyaura cross-coupling reactions. This Pd–Co/G material also possessed other advantages such as low-cost, easy recycled from reaction system by a magnet for their magnetic property, and easy experimental handling. 相似文献
17.
聚类分析在股票市场板块分析中的应用 总被引:7,自引:1,他引:7
本文将聚类分析应用于股票市场的研究,研究实例表明,聚类分析方法是股市板块分析中的一种有效、实用的方法 相似文献
18.
To solve the problem of organic-inorganic light conductive composite interface features, transparent resin and cement matrix were used as carriers to further study features of the organic-inorganic interface formed by transparent resin and cement matrix and the interface modification of the coupling agent. The bond strength, micro-hardness, microstructure and surface morphology of a resin light conductive cementitious materials (RLCCM) interface were evaluated by tests of tensile and oblique shear, micro-hardness, environmental scanning electron microscopy, and atomic force microscope. The results show that the silane A-151 and aluminate coupling agent could significantly improve interface bond properties of RLCCM. At 7 d, the interface tensile bond strength of the silane A-151 and aluminate coupling agent increased by 117 and 105%, respectively. At 28 d, strength on average increased by 73%. At 7 d, interface shear strength the silane A-151 and aluminate coupling agent of 45° increased by 43 and 53%, respectively, At 28 d, strength on average increased by 40%. The transparent resin performance weakened region thickness up to 100 μm; the hardness of the transparent resin in the transition region was increased by 19.6 and 39.9%, respectively. Silane coupling agent A-151 and cement hydration products formed flat spherical particles with diameter of approximately 78 nm, and these particles mosaicked and fused in the surface of the hydrate; therefore, the surface became denser and smoother. 相似文献
19.
质子探针在流体包裹体分析中的应用 总被引:2,自引:1,他引:2
本文着重阐述了质子探针无标样定量分析流体包裹体的方法原理、技术要点和分析时注意的问题。作者对我国斑岩铜矿石英中的流体包裹体进行了分析,还就国内外质子探针分析流体包裹体的现状进行了评述和展望。 相似文献
20.
With through space and through bond experiments in two-dimensional NMR we analyze the transformation from the thorium phosphate-hydrogen phosphate hydrate (TPHPH) to the β form of the thorium phosphate diphosphate (β-TPD) in relation with the phosphorus networks. These techniques are complementary: the through space coupling gives an insight on the dipolar phosphorus networks while the through bond coupling is particularly efficient in the detection of the P2O7 groups. With these experiments we show that in a first step, by heating the precursor TPHPH above 250 °C, it transforms into an form of TPD. This transformation is due to the complete condensation of hydrogen phosphate groups HPO4 into P2O7 entities. By heating -TPD above 950 °C it transforms into its well-known β form. The form is characterized by a hygroscopic behavior: some water molecules are present near the P2O7 groups that makes non-equivalent their phosphorus nuclei. PO4 dipolar networks are always present in the form. The main effect of these PO4 and P2O7 units is to give the system a channel structure and the water enters in them. 相似文献