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Kochi, Japan

Kawasegi N.,Japan Central Research Institute of Electric Power Industry | Ozaki K.,University of Toyama | Morita N.,Chiba University | Nishimura K.,Kochi FEL Co.
Advanced Materials Research | Year: 2014

A focused ion beam (FIB) is an effective means of fabricating micro- to submicro-scale shapes on diamond cutting tools. However, ion irradiation of diamond tools causes ion implantation, defects, and non-diamond phases, all of which degrade the tool performance. To remove affected layers from FIB-irradiated diamond tools, heat treatment in air was applied, and the effect of the heating parameters on the etchability of the irradiated area was investigated. It was found that the affected layer could be etched and removed from the diamond tool surface, even at 500 °C. In machining experiments on aluminum alloy and nickel phosphorus, machining performance was improved by the applied heating technique, and the cutting forces and machined surfaces were similar to those obtained with the non-irradiated tool. These results indicate that the proposed heating technique is effective for diamond cutting tools shaped by FIB. © (2014) Trans Tech Publications, Switzerland. Source


Kawasegi N.,Japan Central Research Institute of Electric Power Industry | Niwata T.,University of Toyama | Morita N.,Chiba University | Nishimura K.,Kochi FEL Co. | Sasaoka H.,Kochi FEL Co.
Precision Engineering | Year: 2013

Tool shape is an important factor determining the shape and accuracy of machined areas in ultra-precision machining. Use of a focused ion beam (FIB) is an effective means to fabricate micro- to submicro-scale tool shapes. However, ion irradiation causes doping and defects in the tool that reduce tool performance. To use FIB machining on a single-crystal diamond tool without degrading tool performance, a combination of 500 °C heat treatment and aluminum deposition was used to remove gallium (Ga) ions induced by ion irradiation. The method was evaluated through machining experiments that showed that irradiation of Ga ions causes work materials to adhere to the tool surface. This adhesion and the resulting rapid tool wear were reduced by heat treatment. The proposed method also improved the transcription ability and wear resistance of the tool so it was capable of producing a surface quality better than or equal to that produced by non-irradiated tools, even over long cutting distances. © 2013 Elsevier Inc. All rights reserved. Source


Hamada K.,Kochi University | Shimasaki K.,Kochi University | Nishimura Y.,Kochi University | Sasaoka H.,Kochi FEL Co. | Nishimura K.,Kochi FEL Co.
Acta Horticulturae | Year: 2011

The aim of this study is to examine the effect of a field emission lamp (FEL) on the proliferation of the protocorm-like body (PLB) of Cymbidium cultured in vitro. Experiment 1: comparisons between several light sources (red and white FEL, fluorescent tube, red LEDs and cool cathode fluorescent lamps (CCFL)) were performed using PLBs of Cymbidium Waltz 'Idol'. Experiment 2: comparison between white FEL and CCFL was performed using PLBs of Cymbidium tracyanum, C. Waltz 'Idol' and C. Pure Propose 'Wedding'. Cultures were maintained at 25°C with a 16-h photoperiod of 14 μmol m -2 s -1 for 42 days. In C. Waltz 'Idol', the number of PLB and root formation rate were similar regardless the light sources. The colour of Cymbidium PLB cultured under red LEDs was yellowish green at 42 days after culture, suggesting low light intensity. However, with white FEL at the same PPFD value, the colour of PLBs was normal green. After 42 days, the fresh weight of the PLBs of the three orchids was significantly higher with FEL than CCFL. The number of PLBs was similar with white FEL and CCFL, except for C. tracyanum, where more PLBs were produced with white FEL than CCFL. These results suggest that this newly developed light source, an FEL with a nano-diamond (ND) emitter, could be used as an energy efficient light source for the propagation of Cymbidium PLBs in vitro. Source


Sasaoka H.,Kochi FEL Co. | Nishimura K.,Kochi FEL Co.
Diamond and Related Materials | Year: 2011

The origin of field emission of nano-crystalline diamond/carbon nanowall (ND/CNW) films prepared by DC plasma CVD has been investigated by macroscopic field emission measurements and SEM observation. We found that there is correlation between the field enhancement factors estimated from Fowler-Nordheim plots and shape parameters of the highest nanorods of ND/CNW films deposited at various deposition times. In addition, it was found that emission site densities were almost independent to the deposition time although the deposition time changed the total nanorod densities by over a factor of ten. We concluded that the origin of field emission of ND/CNW films derives from a part of the highest nanorods which mainly grow during CNW deposition. © 2011 Elsevier B.V. All rights reserved. Source


Kono S.,Tohoku University | Kono S.,Aoyama Gakuin University | Otani H.,Tohoku University | Goto T.,Tohoku University | And 2 more authors.
e-Journal of Surface Science and Nanotechnology | Year: 2011

A carbon film composed of graphite sticks as field emission (FE) points is studied using field/photoemission electron microscopy (F/PEEM) and scanning electron microscopy (SEM). The film is termed an ND/CNW film since nano-crystalline diamond is grown over a carbon nano-wall layer in the film. It was found that about 8% of graphite sticks present on the ND/CNW film work as field emitters. The sizes and postures of three representative graphite sticks that work as field emitters are determined by SEM observations. The time dependence of the FE current of the single emission sites was measured by FEEM at a field of 1.0 V/μm. The average FE current from a single emission site for the field of 1.0 V/μm is found to be 10-100 nA. This time dependence of the FE current was compared with those of FE currents of other carbon nano-materials. The results suggest that the cause of FE fluctuation is adsorption and desorption of molecules on the emission site, indicating the reason for the prolonged FE lifetime of the graphite sticks on the ND/NCW films. © 2011 The Surface Science Society of Japan. Source

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