Third sound is known to depend on the chemistry and geometry of the substrate on which a superfluid film is adsorbed. We have studied third sound in films adsorbed on multiwall carbon nanotubes to determine the effects of the cylindrical nanotube geometry. The Van der Waals potential for a single nanotube and the theoretical propagation velocity on the outer surface of a nanotube are presented....

Multiwall carbon nanotubes (MWCNTs) were oxidized with different agents and a characterization study was carried out. Then, hybrid-magnetic nanoparticles (HMNPs) were synthesized as iron oxide supported on the selected multiwalled carbon nanotubes (MWCNTs-Fe₃O₄) obtained from MWCNTs oxidized with HNO3. The HMNPs characterization revealed the presence of iron oxide as magnetite onto the MWCNTs s...

We attempt to understand the fundamental factors that determine the growth rate of carbon nanotubes. In a series of experiments on growing multiwall carbon nanotubes (MWNTs) by thermal chemical vapor deposition, we found that the addition of carrier gas and the type of carrier gas can change the growth rate, growth density, and structures of MWNTs. We explain these results based on the dissocia...

Bending-mode vibrations of carbon nanotube resonators were mechanically detected in air at atmospheric pressure by means of a novel scanning force microscopy method. The fundamental and higher order bending eigenmodes were imaged at up to 3.1 GHz with subnanometer resolution in vibration amplitude. The resonance frequency and the eigenmode shape of multiwall nanotubes are consistent with the el...

This research demonstrates the capability of controlled, focused ion beam (FIB)–assisted tailoring of morphologies in both multiwall carbon nanotubes (CNTs) and Y junction nonlinear CNT systems through defect engineering. We have shown that a 30 keV FIB Ga ion beam at low ion milling currents of 1 pA can be used to partially reduce the CNT diameter, to provide electrical conduction bottleneck m...

The transmission electron microscopy images of in situ prepared multiwall carbon nanotubes MWNTs and polyaniline PANI composites show that nanotubes are well dispersed in aqueous medium, and the nanofibers of PANI facilitate intertube transport. Although low temperature transport indicates variable range hopping VRH mechanism, the dc and ac conductivity become temperature independent as the MWN...