| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2000: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 1999: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Research Abstract |
In order to analyze the three-dimensional structure of three-dimensional Coulomb crystals, blue argon-ion-laser light (488nm) and red diode-laser light (690nm), which was expanded by a cylindrical lens perpendicular to an re electrode, were irradiated at the same time to fine-particles, and top views were obtained by the blue light and side views by the red light through a optical filter of the color. By the observation of top and side views at the same time and at the same position using this method, accurate analyses have become possible. The analysis of transition process of Coulomb crystal structures has become also possible every 1/30 seconds.
Using these analytical methods, we observed, in three-dimensional Coulomb crystals, body-centered-cubic (bcc)-like structures (011) or (001) planes parallel to the electrode, face-centered-cubic (fcc)-like structures (111) planes parallel, and hexagonal-close-packed-like structures (0001) parallel. The ratio among three lattice constants for the bcc-like structure was 1 : 1.56 : 1.53, which shows that the crystal should be called the body-centered-tetragonal (bct) lattice. For the fcc-like structure, the ratio of the lattice constant in the close-packed plane to the distance between the neighboring planes was 1 : 0.83, which is very close to the ratio for fcc lattice. The coexistence of fcc and bct structures and the transition between the two structures were observed and analyzed. From the results, it was confirmed that the structural change occurred by the slip in crystal planes between fcc (111) and bct (001) to the direction of fcc [110] and bct [111]. The transition corresponds to the martensitic transformation of carbon steel.
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