Gigas Growth of Carbon Nanotubes

An exceptionally high yield of carbon nanotubes (CNTs) has been achieved by chemical vapour deposition (CVD) of camphor over zeolite support. A simple 30 min CVD of 12 g camphor over Fe-Co-impregnated zeolite at 650 °C in an academic laboratory setup, yields 6 g multiwalled CNTs of dia ~10 nm with an as-grown purity of ~88 per cent. Owing to the enormous CNT growth,the zeolite bed inflates by 1000 wt per cent and 10,000 vol per cent. Camphor-to-CNT production efficiency is 50 per cent and net carbon-to-CNT conversion efficiency is 61per cent. These figures are incomparably higher than that of any CNT precursor by any method. Hence it is called‚gigas growth™. The technique greatly complies with the principles of green chemistry, and thus sets an example of an environment-friendly nanotechnology.Defence Science Journal, 2008, 58(4), pp.496-503, DOI:http://dx.doi.org/10.14429/dsj.58.167

Development of a momentum vector measurement instrument in steady-state plasmas

Momentum vector measurement instrument yielding individual and simultaneous identification of local fluxes of momentum components in two different directions, i.e., vector-resolved force, is developed for understanding momentum transport in plasmas and the thrust generation mechanisms of a helicon plasma thruster. A detector plate is attached to a rotational arm connected to a pivot, which has a structure accessible to the inside of the thruster and is mounted on an axially movable balance structure. Simultaneous measurements of displacements of the rotational arm and the axially movable balance give the fluxes of the two different components of the momentum flowing into the detector surface, respectively, e.g., the radial and axial components. The detailed calibration results and the displacement signals induced by applying known forces in a bench test are shown. The results show that the presently developed technique gives resolutions of about 10 μN in the two different directions independently

Small Angle X-Ray Scattering Imaging of Soft Tissue by Using Laue Diffraction Optical System

We performed a feasibility study of Small angle X-ray scattering imaging under the condition of X-ray bright field imaging by Laue crystal diffraction optics of X-ray dark-field imaging that works as an angular analysis. Collagen in chicken tibia containing abundant soft fibrous tissue was chosen as a specimen. In traditional Small angle X-ray scattering optical system, we can derive the structure information of sample by calculating q value which is available from a scattering pattern. Thus it is usually necessary to conduct a 2D scan in order to obtain scattering image. In this paper it is described by a method by which not only small angle X-ray scattering imaging is available directly but also bright-field imaging and dark-field imaging can be obtained at the same time. As the first step, the feasibility of the imaging method should be confirmed by taking pictures of the samples with known periodic length. The preliminary test showed that the collgan’s lattice spacing d is 65.1 nm that was also taken photos by scanning electron microscopy. By rotating Laue angular analyzer by 112 arcseconds small angle X-ray scattering image appeared in bright-field