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Uniform Diameter (uniform + diameter)
Selected AbstractsWell-Aligned ZnO Nanowire Arrays Fabricated on Silicon Substrates ,ADVANCED FUNCTIONAL MATERIALS, Issue 6 2004C. Geng Abstract Arrays of well-aligned single-crystal zinc oxide (ZnO) nanowires of uniform diameter and length have been synthesized on a (100) silicon substrate via a simple horizontal double-tube system using chemical vapor transport and condensation method. X-ray diffraction and transmission electron microscopy (TEM) characterizations showed that the as-grown nanowires had the single-crystal hexagonal wurtzite structure with detectable defects and a <0002> growth direction. Raman spectra revealed phonon confinement effect when compared with those of ZnO bulk powder, nanoribbons, and nanoparticles. Photoluminescence exhibited strong ultraviolet emission at 3.29,eV under 355,nm excitation and green emission at 2.21,eV under 514.5,nm excitation. No catalyst particles were found at the tip of the nanowires, suggesting that the growth mechanism followed a self-catalyzed and saturated vapor,liquid,solid (VLS) model. Self-alignment of nanowires was attributed to the local balance and steady state of vapor flow at the substrate. The growth technique would be of particular interest for direct integration in the current silicon-technology-based optoelectronic devices. [source] Free-Standing All-Nanoparticle Thin Fibers: A Novel Nanostructure Bridging Zero- and One-Dimensional Nanoscale Features,ADVANCED MATERIALS, Issue 3 2009Jia Yan Zero-dimensional nanoparticle structures have a prominent role as building blocks for complex assemblies. However, major barriers to the construction of 1D assemblies using 0D elements exist. The fabrication of free-standing all-nanoparticles thin fibers is presented, where the fibers have a uniform diameter (1.5,µm) and a high aspect ratio (length/diameter , 2500). [source] The electronic structure of a Bi/Sb superlattice nanowirePHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 2 2007G. R. Zhang Abstract The electronic structure of a Bi/Sb superlattice nanowire have been investigated using a theoretical model, in which the nanowire is assumed to possess a circular cross section with a uniform diameter. The variation of the electronic structure as a function of segment length and the total density of states for a Bi/Sb superlattice nanowire with a certain diameter of 5 nm are presented. The minigaps in the total density of states may lead to change in sign of the thermopower for certain energy ranges as the Fermi energy varies, which indicates that the superlattice nanowire can demonstrate n - or p -type behavior by using the same dopants. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Role of Nanosized Zirconia on the Properties of Cu/Ga2O3/ZrO2 Catalysts for Methanol SynthesisCHINESE JOURNAL OF CHEMISTRY, Issue 2 2006Xin-Mei Liu Abstract The introduction of mesoporous nanosize zirconia to the catalyst for methanol synthesis dedicates the nanosized catalyst and mesoporous duplicated properties. The catalyst bears the larger surface area, larger mesoporous volume and more uniform diameter, more surface metal atoms and oxygen vacancies than the catalyst prepared with the conventional coprecipitation method. The modification of microstructure and electronic effect could result in the change of the reduced chemical state and decrease of reducuction temperature of copper, donating the higher activity and methanol selectivity to the catalyst. The results of methanol synthesis demonstrate that the Cu+ is the optimum active site. Also, the interaction between the copper and zirconia shows the synergistic effect to fulfil the methanol synthesis. [source] Silk Fibers Extruded Artificially from Aqueous Solutions of Regenerated Bombyx mori Silk Fibroin are Tougher than their Natural CounterpartsADVANCED MATERIALS, Issue 3 2009Guanqiang Zhou Regenerated silk fibers extruded from fibroin solutions are highly lustrous and have uniform diameters and circular cross-sections. They are stronger, more extensible, and tougher than natural silkworm silk. These fibers can be spun under clean, sterile, and carefully regulated conditions, and may permit direct incorporation of drugs for controlled release, being suitable for biomedical applications. [source] Nucleation and Growth of Boron Nanowires on ZrB2 Particles,CHEMICAL VAPOR DEPOSITION, Issue 7 2006L. Guo Abstract Amorphous boron rich nanowires are grown on ZrB2 particles using diborane as the gas precursor in a CVD process under 20,Torr pressure and at 900,°C. These nanowires have uniform diameters of tens of nanometers and lengths of up to several micrometers. The boron-rich nanowires are characterized and found to be composed of boron clusters containing unit cells of icosahedral B12. A surface nucleation and growth mechanism of solid boron from vapor phase is proposed to explain the nanowire growth. The role of ZrB2 particles in the synthesis of the boron-rich nanostructures is also discussed. [source] |