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121.
Tago Teruoki Tashiro Shizuka Hashimoto Yukiko Wakabayashi Katsuhiko Kishida Masahiro 《Journal of nanoparticle research》2003,5(1-2):55-60
Silica (SiO2)-coated ceria (CeO2) nanoparticles were prepared using water-in-oil microemulsion. Polyoxyethylene (15) cetylether and cyclohexane were used as a surfactant and organic solvent. SiO2-coated CeO2 nanoparticles were obtained by hydrolysis of metal alkoxide (tetraethylorthosilicate, TEOS) in the solution containing CeO2 precursor nanoparticles. The effects of CeO2 sources (Ce metal salt) and CeO2 particle-forming agents on the morphology of SiO2–CeO2 particles were investigated. Observation via transmission electron microscopy revealed that the type of particle-forming agent affected the nanoparticles' morphology and that CeO2 nanoparticles were spherically coated with SiO2 when using oxalic acid ((COOH)2) as a particle-forming agent of CeO2. Furthermore, the transmittance of the particles was high in the visible region (above 400 nm) and decreased in the ultraviolet region. 相似文献
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L. Sánchez J. L. Tirado C. Pérez Vicente J. C. Jumas 《Journal of Solid State Electrochemistry》1998,2(5):328-333
Lithium and sodium have been topotactically inserted in the lattice of TaFe1.25Te3 by electrochemical procedures. The existence of electronically unequivalent sites occupied by tellurium atoms conditions
a two-step insertion process. In each step, the alkali metal ions occupy empty sites in the structure which are coordinated
by tellurium atoms of a different set of sites. The␣thermodynamic and kinetic parameters of Li
x
TaFe1.25Te3 and Na
x
TaFe1.25Te3 have been determined and compared with other inserted binary and ternary chalcogenides. The values of the free energy of
intercalation are less negative than those previously reported for TaTe2 and close to those found for the misfit layer compound (PbS)1.13TaS2. The values of alkali metal ion diffusivity are closer to those reported for the binary telluride, due to the similarities
in the atoms exposed to the interlayer space.
Received: 14 October 1997 / Accepted: 14 November 1997 相似文献
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ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option. 相似文献
128.
A comparison study of the photoluminescent (PL) spectra in pure and ultra-pure irradiated and annealed germanium has been performed. Some radiative recombination centres including impurities have been found. The spectra of samples bombarded by neutrons were found to include, along with the lines from intrinsic defects (Z, Y, X, W, V), the centres due to hydrogen and oxygen impurities (the lines T1, T2, U). A considerable number of the lines (A1-A3, B1, B2, C, D1, D2) in the PL spectra of crystals exposed to gamma-quanta and electrons were identified with the centres including carbon atoms. Such a great set of lines, presumably, results from the transformation of the above mentioned complexes in the course of annealing. The observed differences in the PL spectra within 0.72 to 0.74 eV range probably indicate a contribution of several types of intrinsic defects and other impurities, along with carbon, to complexing. 相似文献
129.
In this work, In/Te bilayer thin films were prepared using sequential thermal evaporation method and subsequently irradiated using swift heavy ions (SHIs) of 100 MeV silicon (Si) with different fluences (1×1013 to 5×1013/cm2). The inter-diffusion of In and Te layers was highly controlled by SHI irradiation and the In2Te3 formation capability was compared with that of the conventional annealing method. The structural as well as optical properties of a post-sintered SHI-irradiated In/Te bilayer were investigated using X-ray diffraction (XRD) measurements and UV–visible spectroscopy, respectively. We found that irradiated samples showed single-phase In2Te3 under post-annealed conditions at 150 °C unlike that prepared using the conventional thermal annealing method, which showed mixed phases under similar conditions. This confirms the effective inter-diffusion in bilayer films by SHI irradiation toward the formation of single-phase In2Te3. The estimated optical band gap energy was found to be 1.1±0.5 eV and strongly corroborated the XRD results. In addition, the estimated refractive index (n) value of the SHI-irradiated sample (~3.3) was higher than that of the sample obtained through the conventional annealing method (~2.8). This proves that SHI offers a highly compact nature even at low temperatures. This work has a wide scope for achieving single-phase alloyed films through bilayer mixing by SHI irradiation. 相似文献
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A theoretical study of a structural transition of secondary phase oxide nanorods in epitaxial YBa2Cu3O7?δ films on vicinal SrTiO3 substrates is presented. Two possible types of film/substrate interface are considered, with one assuming complete coherence, while the other is defective as manifested by the presence of antiphase grain boundaries. Only in the former case does the increase of the vicinal angle of the substrate lead to a substantial change of the strain field in the film, resulting in a transition of the nanorod orientation from the normal to the in-plane direction of the film. The calculated threshold vicinal angle for the onset of the transition and lattice deformation of the YBa2Cu3O7?δ film due to the inclusion of the nanorods is in very good agreement with experimental observations. This result sheds lights on the understanding of the role of the film/substrate lattice mismatch in controlling self-assembly of dopant nanostructures in matrix films. 相似文献