| Project/Area Number |
17560649
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Metal making engineering
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| Research Institution | Tohoku University |
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Principal Investigator |
MATSUTA Hideyuki Tohoku University, Institute for Materials Research, Research associate, 金属材料研究所, 助手 (00181735)
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| Co-Investigator(Kenkyū-buntansha) |
WAGATSUMA Kazuaki Tohoku University, Institute for Materials Research, Professor, 金属材料研究所, 教授 (30158597)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2006: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2005: ¥3,100,000 (Direct Cost: ¥3,100,000)
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| Keywords | Laser-induced plasma / Spark discharge / Optical emission / Stabilization / Control of discharge |
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| Research Abstract |
A combined technique with laser irradiation is proposed to control spark discharge for analytical use, having a unique feature that firing points of the spark discharge can be fixed by laser irradiation. Because the spark discharge easily initiates at particular surface sites, such as non-metallic inclusions, called selective discharge, the concentration of some elements sometimes deviates from their average one in spark discharge optical emission spectrometry. Therefore, stabilization of firing points on a sample surface could improve the analytical accuracy and precision.
When a tungsten stylus having a round-shaped tip and an iron plate were used as the counter and the sample electrodes, it was very difficult to induce spark discharges between these electrodes having distances of a few mm in air, and a closer spacing of less than 0.7 mm was required to generate the spark discharge under our experimental conditions. By introducing laser irradiation, the electrode distance could be extended up to 3.5 mm while keeping stable spark discharges.
We also moved a tungsten stylus electrode to within 2 mm horizontally from the breakdown position of the laser-induced plasma The spark channel could be maintained between the stylus electrode and the breakdown position regardless of the length of the spark channels. It is found that the initiation site of a spark discharge can be controlled by laser irradiation.
By using the present combined technique, emission intensity of Fe I 373.5 nm was enhanced 1.5 times brighter than the one obtained by a spark discharge spectrometry alone. This may be due to the additional increment of a sampling amount by laser ablation in addition to the one obtained by a spark discharge alone.
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