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Nanotube Bundles (nanotube + bundle)
Kinds of Nanotube Bundles Selected AbstractsA Waveguide-Like Effect Observed in Multiwalled Carbon Nanotube BundlesADVANCED FUNCTIONAL MATERIALS, Issue 14 2010Shengyong Xu Abstract The delay time of nanosecond electromagnetic pulses is measured in multiwalled carbon nanotube (MWCNT) bundles and copper wires, with a length of up to 3,cm, as compared with that in standard coaxial cables of the same lengths. Under certain configurations, when the Cu core of a coaxial cable is replaced with a MWCNT bundle of the same length, the measured delay time of a pulsed signal is shortened. The difference between the delay time measured for a device with a Cu core and that of a device with a MWCNT bundle of the same length increases with the length of the samples. The results imply that, compared with Cu wires, MWCNT bundles may be more efficient in guiding the transmission of high-frequency signals along their longitudinal axis, showing a waveguide-like effect. [source] In situ Mechanical Testing Reveals Periodic Buckle Nucleation and Propagation in Carbon Nanotube BundlesADVANCED FUNCTIONAL MATERIALS, Issue 14 2010Shelby B. Hutchens Abstract Uniaxial compression studies are performed on 50-µm-diameter bundles of nominally vertical, intertwined carbon nanotubes grown via chemical vapor deposition from a photolithographically defined catalyst. The inhomogeneous microstructure is examined, demonstrating density and tube orientation gradients, believed to play a role in the unique periodic buckling deformation mechanism. Through in situ uniaxial compression experiments it is discovered that the characteristic bottom-to-top sequential buckling proceeds by first nucleating on the bundle surface and subsequently propagating laterally through the bundle, gradually collapsing the entire structure. The effects of strain rate are explored, and storage and loss stiffnesses are analyzed in the context of energy dissipation. [source] Behavior of Ni-Doped MgMoO4 Single-Phase Catalysts for Synthesis of Multiwalled Carbon Nanotube BundlesCHEMICAL VAPOR DEPOSITION, Issue 1 2007Y. Li Abstract A significant effect is found when various ratios of CH4/H2 and CH4/N2 are used for the synthesis of multiwalled carbon nanotube (MWNT) bundles on nickel-doped MgMoO4 (Ni/Mo/MgO) as a catalyst. The absorption of hydrogen makes the nickel,molybdenum nanoparticles highly dispersed on the porous MgO, and the synergism of nickel,molybdenum has the effect that sufficient carbon atoms are rapidly dissolved in the molten nickel-molybdenum nanoparticles, leading to a high yield of MWNTs. The phase transformations of the catalysts and the formation mechanism of the MWNT bundles on Ni/Mo/MgO catalyst are also presented. [source] Nanocrystalline non-planar carbons: Growth of carbon nanotubes and curled nanostructuresCRYSTAL RESEARCH AND TECHNOLOGY, Issue 10-11 2005S. Orlanducci Abstract We present a variety of non-planar graphitic nanostructures selectively generated in a modified Hot-Filament Chemical Vapour Deposition (HF-CVD) apparatus, using purpose-synthesized amorphous carbon nanoparticles or graphite powders as solid state precursor. The employed methodologies enable to successfully synthesize homogeneous and well organized deposits of single- and multi-walled carbon nanotubes, onion-like nanostructures, and nanotube bundles coated by nano-sized diamond grains. Variations in the morphological aspect of such non-planar graphite-based nanostructures are observed changing the experimental conditions: the solid state reactants, the filament and substrate temperatures, the catalyst concentration, and the atomic hydrogen flux over the substrate play key roles in the phenomenon. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Carbon Nanotube Polycarbonate Composites for Ultrafast Lasers,ADVANCED MATERIALS, Issue 21 2008Vittorio Scardaci Carbon nanotube polycarbonate composites with controlled nanotube-bundle size are prepared by dispersion with conjugated polymers followed by blending with polycarbonate. The composite has uniform sub-micrometer nanotube bundles in high concentration, shows strong nonlinear optical absorption, and generates 193 fs pulses when used as passive mode-locker in a fiber laser. [source] A molecular dynamics simulation of air adsorption in single-walled carbon nanotube bundlesINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 10 2008Víctor Rojas Cervellera Abstract The physisorption of air in single-walled carbon nanotubes (SWNTs) is studied employing molecular dynamics. The effect of the nanotube diameter in the gas adsorption capacity of SWNT bundles has been investigated using (10,0), (15,0), and (20,0) SWNTs finding an increasing load capacity. The O2:N2 ratio in the nanotube bundles is analyzed in detail as well, comparing it to that in the gaseous bulk. The air contained in the carbon nanostructures has a larger content in O2 than the bulk air, thus providing a possible application of carbon nanotubes as molecular filters. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008 [source] Raman spectroscopy on carbon nanotubes at high pressureJOURNAL OF RAMAN SPECTROSCOPY, Issue 7-8 2003I. Loa Abstract Raman spectroscopy has been the most extensively employed method to study carbon nanotubes at high pressures. This review covers reversible pressure-induced changes of the lattice dynamics and structure of single- and multi-wall carbon nanotubes and irreversible transformations induced by high pressures. The interplay of covalent and van der Waals bonding in single-wall nanotube bundles and a structural distortion near 2 GPa are discussed in detail. Attempts to transform carbon nanotubes into diamond and other ,superhard' phases are reviewed critically. Copyright © 2003 John Wiley & Sons, Ltd. [source] | |||||||||||||