| Project/Area Number |
12450354
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
無機工業化学
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| Research Institution | The University of Shiga Prefecture |
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Principal Investigator |
MATSUOKA Jun (2001-2002) The University of Shiga Prefecture, School of Engineering, Associate Professor, 工学部, 助教授 (20238984)
曽我 直弘 (2000) 滋賀県立大学, 工学部, 教授 (80026179)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHIDA Satoshi The University of Shiga Prefecture, School of Engineering, Research Associate, 工学部, 助手 (20275168)
松岡 純 滋賀県立大学, 工学部, 講師 (20238984)
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| Project Period (FY) |
2000 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥10,700,000 (Direct Cost: ¥10,700,000)
Fiscal Year 2002: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2001: ¥4,000,000 (Direct Cost: ¥4,000,000)
Fiscal Year 2000: ¥5,600,000 (Direct Cost: ¥5,600,000)
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| Keywords | silicate glass / fracture / structural change / heat of solution / internal energy / shelyubskii method / electron spin resonance / E' center / ガラス空隙度 / 破壊特性 / 高密度化 / 緩和挙動 / 活性化エネルギー / ガラス / ESR / E'欠陥 / 緩和 / 空隙度 / 構造空隙 / 分相 / パイレックスガラス / シリカガラス |
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| Research Abstract |
Fracture-induced structural change and its recovery by heat treatment of crushed silica glass were investigated by means of heat of solution to hydrofluoric acid, Shelyubskii optical scattering, and electron spin resonance. Heat of solution of the as-crushed silica glass with average powder size of 31μm is 20kJ/mol higher than the sample well annealed at 973K after crushing. This means that the crushing makes the silica glass higher-energy structure than the annealed one. Shelyubskii optical scattering study shows the similar tendency, i.e., scattering from as-crushed silica glass is very large which means that the inhomogeneity in refractive index is high, and it becomes small by annealing at 973K. Structure recovery by annealing at 973K is almost finished within 10hr both in heat of solution and in optical scattering. However, this recovery is not complete, and further recovery is observed by the heat treatment at 1173K. Electron spin resonance study shows that the crushing causes the formation of E' center in silica glass. The created E' center vanishes by immersing the sample to water in a short time, which indicated that the position of E' center is near the surface formed by crushing.
The magnitude of this strain is also estimated from the viewpoint of change in internal energy for 15Na_2O-10CaO-75SiO_2 and 10K_2O-38PbO-52SiO_2 glasses. The difference in heat of solution between as-crushed and well-annealed samples was regarded as the change in internal energy by fracture. The change in internal energy of glass by crushing is about 10kJ/mol-SiO_2 for silica, 7kJ/mol-SiO_2 for soda-lime silicate, and 2kJ/mol-SiO_2 for lead silicate. Composition dependence of the magnitude should be due to the difference in free volume of glasses, i.e., glass with large free volume will give large fracture-induced strain.
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