The authors demonstrated a new method for inducing enormous shrinkage in single-walled carbon nanotube bundles by applying low energy electron beam irradiation along with supersonic vibration, and a maximum shrinkage rate of À100% cm 2 /C was obtained under electron acceleration of 1 keV. The characteristic feature of the shrunken single-walled carbon nanotubes was a wavy deformation that affected the entire bundle. The authors believe that a uniaxial stress induced by the supersonic vibration broke the equilibrium of the internal stress and allowed the uniform accumulation of defects under low energy electron beam excitation. The wavy deformation of the single-walled carbon nanotubes resulted in the enormous shrinkage of the bundle.

A novel catalyst structure for continuous growth of nanocarbon fibers is proposed. In this structure, catalyst nanofibers are embedded in a membrane that separates the growth ambient into carbon-supplying and carbon-precipitating environments. The catalyst nanofibers pierce through the membrane so that carbon source gas is supplied only to one end of the catalyst fibers and nanocarbon fibers grow continuously at the other end. To realize this structure, self-supporting anodized alumina was used as a membrane, and its nano-through-holes were filled with catalyst Ni in supercritical CO2 fluid. Direct carbon growth from the Ni nanofibers was confirmed using this catalyst structure.

We report the fabrication of centimeter-long, defect-free, and parallel-aligned single-wall carbon nanotubes (SWCNTs) using a laboratory-designed two-step catalytic chemical vapor deposition method. Our in situ mass spectral analysis reveals that the initial stainless-derived iron oxide block decomposes methane into acetylene and ethylene, subsequently promoting the growth of high-purity SWCNTs on the second pigment-derived iron oxide fine powders dispersed on the Si/SiO2 substrate. Raman spectral imaging shows the negligible defect-induced D-band in the resulting sample, indicating the highly crystalline structure of SWCNTs. By using a gas-flow-type mechanical test system, an SWCNT bundle containing 20 components of individual SWCNTs exhibits the tensile strength over 50 GPa. Since the catalysts used in this study are widely available on the industrial scale, our iron oxide coassisted method will lead to the scalable production of high-strength SWCNT bundles.

We produced novel carbon nanofibers (CNFs) by oxidizing high-purity iron foil and then carburizing it in acetylene gas flow. This formed cracks in the heat-treated iron foil with CNFs bridging the two walls of each crack. The CNFs were drawn out from the walls as the crack opened during heat treatment. This will be a new method to grow and arrange carbon nanotubes and nanosheets without using metal nanoparticles or template substrates

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