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781.
Surface nitrogen complex formation upon reaction of coal char with NO at 600°C was studied by X-ray photoelectron spectroscopy. Particle size had a noticeable effect on the magnitude of changes, which was observed on the surface of the coal char in the nitrogen functional group. The surface increased its -NO, pyridine-N-oxide, and -NO2 functional group contents with a decrease in particle size. The chemisorption processes of NO molecules on the char were simulated using the ab initio Hartree–Fock method and density functional theory. Molecular modeling was applied to determine the thermodynamics of the reactions. Mechanisms were proposed to explain the formation of the -NO, pyridine-N-oxide, and -NO2 functional groups at 600°C. 相似文献
782.
Using carbon nanotubes as nanobarriers, the growth of single-walled carbon nanotubes (SWNTs) on a quartz surface can be terminated. First, carbon nanotube nanobarriers were grown on a quartz surface by the gas flow-directed growth mode. Then, the SWNTs were grown on the quartz surface via the lattice-oriented growth mode, in which growth of SWNTs can be terminated by hitting the nanotube nanobarriers. Moreover, using the carbon nanotube nanobarrier as a marker, the mechanism of the growth of SWNTs on the quartz surface can be studied; a base-growth mechanism is indicated. Based on this termination process and the base-growth mechanism, SWNT arrays with controlled lengths can be grown on a quartz surface by fixing the sites of both catalysts and nanobarriers. 相似文献
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Author co-citation analysis (ACA) is an important method for discovering the intellectual structure of a given scientific
field. Since traditional ACA was confined to ISI Web of Knowledge (WoK), the co-citation counts of pairs of authors mainly
depended on the data indexed in WoK. Fortunately, Google Scholar has integrated different academic databases from different
publishers, providing an opportunity of conducting ACA in wider a range. In this paper, we conduct ACA of information science
in China with the Chinese Google Scholar. Firstly, a brief introduction of Chinese Google Scholar is made, including retrieval
principles and data formats. Secondly, the methods used in our paper are given. Thirdly, 31 most important authors of information
science in China are selected as research objects. In the part of empirical study, factor analysis is used to find the main
research directions of information science in China. Pajek, a powerful tool in social network analysis, is employed to visualize
the author co-citation matrix as well. Finally, the resemblances and the differences between China and other countries in
information science are pointed out. 相似文献
786.
Characterization and photoluminescence studies of CdTe nanoparticles before and after transfer from liquid phase to polystyrene 总被引:1,自引:0,他引:1
Shugang Wang Yaoxian Li Jie Bai Qingbiao Yang Yan Song Chaoqun Zhang 《Bulletin of Materials Science》2009,32(5):487-491
The major objective of this work was to detect the change of photoluminescence (PL) intensity of CdTe nanoparticles (NPs)
before and after transfer from liquid phase to polystyrene (PS) matrix by electrospinning technique. Thio-stabilized CdTe
NPs were first synthesized in aqueous, then enwrapped by cetyltrimethylammonium bromide (CTAB), and finally, transferred into
PS matrix to form CdTe/PS nanofibres by electrospinning. Then, CdTe/PS nanofibres were characterized by scanning electron
microscope (SEM) and transmission electron microscope (TEM) to observe their morphology and distribution, respectively. The
selective area electronic diffraction (SAED) pattern proved that the CdTe NPs were cubic lattice. The PL spectrum indicated
that CdTe NPs have been transferred into PS nanofibres, and the PL intensity of CdTe NPs in the nanofibres was even higher
than that before CdTe NPs were introduced into PS nanofibres. Moreover, X-ray photoelectron spectra (XPS) revealed that thiol-stabilized
CdTe NPs were enwrapped by CTAB, and PS acted as a dispersant in the process of electrospinning. 相似文献
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基于多物理场耦合框架MOOSE,采用五方程两相流模型开发了模块化程序ZEBRA,实现了高阶时间、空间离散格式两相流动传热问题的求解。采用Bartolomei开展的垂直圆管过冷沸腾实验对ZEBRA进行验证,在不同热流密度、质量流密度、压力工况下,将程序计算值与实验值进行了数值验证和计算分析。结果表明:ZEBRA中五方程模型预测值与实验值符合良好,沸腾起始点和空泡份额的预测合理,表明ZEBRA初步具备了处理两相流问题的能力。 相似文献
790.