The rolling up of a graphene sheet into a tube is a standard visualization tool for illustrating carbon nanotube (CNT) formation. However, the actual processes of rolling up graphene sheets into CNTs in laboratory syntheses have never been demonstrated. Here we report conformal growth of graphene by carbon self-assembly on single-wall and multi-wall CNTs using chemical vapor deposition (CVD) of...

In the present work, a prototype of a new type of solar collectors, which called Direct Absorption Solar Collector, was built and its thermal performance is experimentally compared with conventional flat plate solar collector under transient and steady state conditions. Different volume fractions of multi wall carbon nanotubes in water and ethylene glycol mixture (70%:30% in volume) were used a...

Using a first-principles method, we study field emission properties of double-wall carbon nanotubes with various end geometries and combinations of inner and outer walls. The open double-wall nanotubes exhibit substantial contribution to the emission current from the extended π states. These states are insensitive to the detailed tip structure or the presence of foreign adsorbed molecules and t...

Brazil has played an important role in the development and use of resonance Raman spectroscopy as a powerful characterization tool for materials science. Here we present a short history of Raman scattering research in Brazil, highlighting the important contributions to the field coming from Brazilian researchers in the past. Next we discuss recent and important contributions where Brazil has be...

air pollution has always been a major problem in metropolises. volatile organic compounds are one of the major pollutants that are caused by incomplete combustion of fuels in vehicles and gasoline evaporation, especially in fueling stations. removing these pollutants through traditional methods has always been considered. the paper investigates and studies chemical adsorption behavior of benzen...

Articles you may be interested in A simple drain current model for single-walled carbon nanotube network thin-film transistors Mobilities in ambipolar field effect transistors based on single-walled carbon nanotube network and formed on a gold nanoparticle template Appl. Strain on field effect transistors with single–walled–carbon nanotube network on flexible substrate Complementary voltage inv...

We have carried out momentum-dependent measurements of the density response function of bulk samples of purified single wall nanotubes using electron energy-loss spectroscopy. Carbon nanotubes support both excitations between delocalized and localized electronic states. The p-plasmon exhibits significant q-dependence, with a dispersion relation similar to that of the graphite plane, demonstrati...

The role of water in carbon feed on the surface-guided growth of horizontally aligned single-walled carbon nanotubes (HA-SWCNTs) was investigated. It is shown that the amount of water can be optimized to favor HA-SWCNT growth, which is proposed to be due to selective etching of carbon deposits at carbon–metal interface. Without water, nanotube–nanotube interaction and carbon accumulation at the...

We report herein the development and preliminary mechanical characterization of fully-dense multi-wall carbon nanotube (MWCNT)-reinforced ceramics and glasses based on a completely new methodology termed High Shear Compaction (HSC). The tubes are introduced and bound to the matrix grains by aid of polymeric binders to form flexible green bodies which are sintered and densified by spark plasma s...