Pavel N Nikolaev

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This does not exclude the possibility, that larger structural fragments (such as tetramers and pentamers) can also contribute to the low-frequency vibrational spectrum around the boson peak. On the basis of these results, the following model of the glass transition of glycerol can be proposed. At temperatures far above Tg (186 K), the lifetime of the MRO or(More)
We describe, in detail, a readily scalable purification process capable of handling single-wall carbon nanotube (SWNT) material in large batches. Characterization of the resulting material by SEM, TEM, XRD, Raman scattering, and TGA shows it to be highly pure. Resistivity measurements on freestanding mats of the purified tubes are also reported. We also(More)
Ž . Single-walled carbon nanotubes SWNTs have been synthesized at milligram per hour rates by the catalytic decomposition of both carbon monoxide and ethylene over a supported metal catalyst known to produce larger multiwalled nanotubes. Under certain conditions, there is no termination of nanotube growth, and production appears to be limited only by the(More)
Results of a parametric study of carbon nanotube production by the double-pulse laser oven process are presented. The effect of various operating parameters on the production of single-wall carbon nanotubes (SWCNTs) is estimated by characterizing the nanotube material using analytical techniques, including scanning electron microscopy, transmission electron(More)
A new method was used to measure the fraction of semiconducting nanotubes in various as-grown or processed single-walled carbon nanotube (SWCNT) samples. SWCNT number densities were compared in images from near-IR photoluminescence (semiconducting species) and AFM (all species) to compute the semiconducting fraction. The results show large variations among(More)
The fluorescence spectra of individual semiconducting single-walled carbon nanotubes embedded in polymer films were measured during the application of controlled stretching and compressive strains. Nanotube band gaps were found to shift in systematic patterns that depend on the (n,m) structural type and are in excellent agreement with the predictions of(More)
The latest process for producing large quantities of single-walled carbon nanotubes (SWNTs) to emerge from the Rice University, dubbed HiPco, is living up to its promise. The current production rates approach 450 mg/h (or 10 g/day), and nanotubes typically have no more than 7 mol % of iron impurities. Second-generation HiPco apparatus can run continuously(More)
We investigate charge transport in a chemically reduced graphene oxide (RGO) film of sub-micron thickness. The I-V curve of RGO film shows current switching of the order of ∼10(5) above the threshold voltage. We found that the observed I-V curve is consistent with quantum tunnelling based charge transport. The quantum tunnelling based Simmons generalized(More)
We demonstrate that argon ion bombardment of single crystal sapphire leads to the creation of substrates that support the growth of vertically aligned carbon nanotubes from iron catalysts with a density, height, and quality equivalent to those grown on conventional, disordered alumina supports. We quantify the evolution of the catalyst using a range of(More)
The colors of suspended metallic colloidal particles are determined by their size-dependent plasma resonance, while those of semiconducting colloidal particles are determined by their size-dependent band gap. Here, we present a novel case for armchair carbon nanotubes, suspended in aqueous medium, for which the color depends on their size-dependent(More)