| Project/Area Number |
61580051
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
結晶学
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| Research Institution | Science University of Tokyo |
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Principal Investigator |
GONDA Takehiko Faculty of Science and Technology, Science University of Tokyo, 理工学部, 助教授 (50084455)
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| Project Period (FY) |
1986 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 1988: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1987: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1986: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | Snow crystal / Ice dendrite / Diffusion field / シュリーレン法 / 水蒸気拡散場 / 雪 / 樹枝状結晶 / 水蒸気の3次元拡散 / 雪結晶の成長 / 氷晶の成長 / 氷晶の成長機構 |
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| Research Abstract |
A schlieren microscope was developed to visualze the diffusion field of water molecules around a dendritic ice crystal. This microscope is different the knife-edge method which was used by onuma et al, (1988), and can visualize the whole area of the diffusion field around the dendritic ice crystal by inserting a black spot at a back focal point of a schlieren lens in front of a growth cell. In the case of vapor growth, the diffusion field around the crystal could not be detected using the schlieren microscope built in this time, because the gradient of the refractive index around the crystal growing from vapor phase, the gradient of water vapor pressure around the crystal is small. However, the diffusion field around a dendritic ice crystal grown in sucrose solution could be easy detected. The effect of the diffusion field on the tip velocity and its shape of primary branches of the dendritic ice crystal was studied by varying the degree of supercooling of sucrose solution, visualizing the diffusion field of water molecules around the crystal growing from sucrose solution. As a result, it was found that the area of the diffusion field around a dendritic ice crystal decreased with increasing tip velocity or deceasing tip radius of the crystal. The area of the diffusion field around the crystal which was detected by the schlieren method corresponds with the area which the gradient of concentration of water molecules arise around the crystal. So, it was experimentaly clarified that the gradient of concentration of water molecules at the tip of an dendritic ice crystal increased with increasing tip velocity or decresing tip radius of the dendritic ice crystal. The same phenomenon can be applied to a snow crystal, an dendritic ice crystal from the vapor phase.
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