Growth of straight carbon nanotubes by simple thermal chemical vapor deposition

Straight carbon nanotubes (CNTs) were achieved by simple thermal chemical vapor deposition(STCVD) catalyzed by Mo-Fe alloy catalyst on silica supporting substrate at 700℃. High-resolution transmission electron microscopy images show that the straight CNTs are well graphitized with no attached amorphous carbon. Mo-Fe alloy catalyst particles play a very crucial role in the growth of straight CNTs. The straight carbon nanotubes contain much less defects than the curved nanotubes and might have potential applications for nanoelectrical devices in the future. The simple synthesis of straight CNTs may have benefit for large-scale productions.

Electrical measurement on individual multi-walled carbon nanotubes

The characterization of electrical property of multi-walled carbon nanotubes (MWCNTs) on a nanometer scale is essential for their potential application in nano-electronic devices. The MWCNTs were synthesized on Fe2O3/SiO2/Si substrate and Pt plate substrate by simple thermal chemical vapor deposition (STCVD) technique and the electrical measurements of individual MWCNT grown on silicon substrate and Pt plate substrate were performed by home-made 'nano-manipulator', respectively. According to current-voltage curves obtained in the experiments the current density that the MWCNTs can carry is calculated to be about 107 A/cm2, which is much larger than that of normal metals.

Production of a High-Mach-Number Plasma Flow for an Advanced Plasma Space Thruster

A higher specific impulse and a larger thrust are required for a mannedinterplanetary space thruster. Prior to a realization of a fusion-plasma thruster, amagneto-plasma-dynamic arcjet (MPDA) powered by a fission reactor is one of the promising candidatesfor a manned Mars space thruster. The MPDA plasma is accelerated axially by a self-induced j x Bforce. Thrust performance of the MPDA is expected to increase by applying a magnetic nozzle insteadof a solid nozzle. In order to get a much higher thruster performance, two methods have beeninvestigated in the HITOP device, Tohoku University. One is to use a magnetic Laval nozzle in thevicinity of the MPDA muzzle for converting the high ion thermal energy to the axial flow energy. Theother is to heat ions by use of an ICRF antenna in the divergent magnetic nozzle. It is found thatby use of a small-sized Laval-type magnetic nozzle, the subsonic flow near the muzzle is convertedto be supersonic through the magnetic Laval nozzle. A fast-flowing plasma is successfully heated byuse of an ICRF antenna in the magnetic beach configuration.

Selective growth of carbon nanotube on silicon substrates

The carbon nanotube (CNT) growth of iron oxide-deposited trench-patterns and the locally-ordered CNT arrays on silicon substrate were achieved by simple thermal chemical vapor deposition(STCVD) of ethanol vapor. The CNTs were uniformly synthesized with good selectivity on trench-patterned silicon substrates. This fabrication process is compatible with currently used semiconductor-processing technologies, and the carbon-nanotube fabrication process can be widely applied for the development of electronic devices using carbon-nanotube field emitters as cold cathodes and can revolutionize the area of field-emitting electronic devices. The site-selective growth of CNT from an iron oxide nanoparticle catalyst patterned were also achieved by drying-mediated self-assembly technique. The present method offers a simple and cost-effective method to grow carbon nanotubes with self-assembled patterns.

Progress in Physics and Technology Developments for the Modification of JT-60

Recent progress in the physics and engineering design study for themodification programme of JT-60 is presented. In order to achieve a steady state high-βplasmaoperation, which is the dominant issue of this programme, physics design for the MHD control and thestability analysis is investigated. Engineering design and the R & D for the superconducting coils,irradiation shield are performed well towards the mission of programme.