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JP

"G" Keywords - 24 Result(s)

G
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 G

[grain boundary character distribution]

Suppression of Intergranular Degradation of Polycrystalline Materials by Grain Boundary Engineering

 
 
 
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特徴・独自性
  • Intergranular degradation often results in decreased lifetime, reliability and economical efficiency of polycrystalline materials. In spite of persistent efforts to prevent such degradation, its complete suppression has not yet been achieved. Grain boundary studies have revealed that coincidence-site-lattice (CSL) boundaries have stronger resistance to intergranular degradations than random boundaries. The concept of ‘grain boundary design and control' has been refined as grain boundary engineering (GBE). GBEed materials which are characterized by high frequencies of CSL boundaries are resistant to intergranular degradations. Our group has achieved very high frequencies of CSL boundaries in commercial stainless steels by GBE. GBEed stainless steels showed significantly stronger resistance to intergranular corrosion (see Figs. 1 and 2), weld-decay, knife-line attack, stress corrosion cracking, liquid-metal embrittlement, radiation damage, etc. and much longer creep life (see Fig. 3) than the unGBEed ones.
実用化イメージ

By using this GBE processing, we expect to conduct effective collaborative research in related fields.

Researchers

Graduate School of Engineering

Yutaka Sato

[grain boundary engineering]

Suppression of Intergranular Degradation of Polycrystalline Materials by Grain Boundary Engineering

 
 
 
NEXT
PREV
特徴・独自性
  • Intergranular degradation often results in decreased lifetime, reliability and economical efficiency of polycrystalline materials. In spite of persistent efforts to prevent such degradation, its complete suppression has not yet been achieved. Grain boundary studies have revealed that coincidence-site-lattice (CSL) boundaries have stronger resistance to intergranular degradations than random boundaries. The concept of ‘grain boundary design and control' has been refined as grain boundary engineering (GBE). GBEed materials which are characterized by high frequencies of CSL boundaries are resistant to intergranular degradations. Our group has achieved very high frequencies of CSL boundaries in commercial stainless steels by GBE. GBEed stainless steels showed significantly stronger resistance to intergranular corrosion (see Figs. 1 and 2), weld-decay, knife-line attack, stress corrosion cracking, liquid-metal embrittlement, radiation damage, etc. and much longer creep life (see Fig. 3) than the unGBEed ones.
実用化イメージ

By using this GBE processing, we expect to conduct effective collaborative research in related fields.

Researchers

Graduate School of Engineering

Yutaka Sato

[green]

Prediction and evaluation of future thermal and wind environments based on CFD, and planning of urban environments adaptable to future climate

 
 
 
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特徴・独自性
  • Numerical simulations of the physical environment of urban outdoor spaces are conducted to predict the physical environment, such as temperature, humidity, wind, and pollutant concentration, and field measurements are conducted to understand the actual physical environment. In addition, the future outdoor environments and heat stroke risks due to global warming are predicted and evaluated.
    Furthermore, the impacts of urban morphology (building shape and layout, street trees, etc.) on the adaptation to severe heat in summer and rare typhoons and floods are evaluated quantitatively.
実用化イメージ

Numerical analysis is used to quantitatively evaluate the "merits and demerits" of designing buildings, planning city blocks and urban areas, and introducing various heat control technologies on the wider thermal environment and the formation of wind ventilation paths, as well as the adverse effects of typhoons and other disasters. The materials for making decisions on whether or not to introduce these technologies are provided.

Researchers

Graduate School of Engineering

Yasuyuki Ishida

[Green Chemistry]

Development of New Reactions Using Organocatalyst

 
 
 
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特徴・独自性
  • Organocatalyst is a synthetically useful catalyst in synthetic organic chemistry, because of the several merits. We have been investigating the development of new and efficient organocatalysts derived from proline. We have already reported the diphenylprolinol silyl ether, which is called as a Jorgensen-Hayashi catalyst, and siloxyproline, which is effective in the presence of water. We have also developed several practical asymmetric catalytic reactions based on the organocatalysts. We also applied these reactions to the total synthesis of natural products and drugs. We have already synthesized Tamiflu in one-pot reaction, and prostaglandin E1 methyl ester via three one-pot procedure.
実用化イメージ

Our newly developed reactions using organocatalysis can be widely used for synthesis of medicines, agrichemicals, and chemical products.

Researchers

Graduate School of Science

Yujiro Hayashi

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