• 제목/요약/키워드: An-Chae

검색결과 5,035건 처리시간 0.039초

압전소자를 이용한 볼트체결 상태계측 및 측정 (Estimation of Fastened Condition of Bolts Using PZT Patches)

  • 채관석;하남;홍동표;채희창
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2004년도 추계학술대회논문집
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    • pp.889-893
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    • 2004
  • This work presents a study on development of a practical and quantitative technique for assessment of the structural health condition by piezoelectric impedance-based technique associated with longitudinal wave propagation method. The bolt fastening condition is adjusted by torque wrench. In order to estimate the damage condition numerically, three damage indices, impedance peak frequency shift ${\Delta}F$ is proposed in this paper. Furthermore, an assessment method is described for estimation of the damage by using these three damage indices.

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압전소자를 이용한 손상계측기술에 관한 기초연구 (Basic research for Health Monitoring Technique with PZT Patches)

  • 하남;채관석;홍동표;채희창
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2004년도 추계학술대회논문집
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    • pp.870-874
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    • 2004
  • This work presents a study on development of a practical and quantitative technique for assessment of the structural health condition by Piezoelectric impedance-based technique associated with longitudinal wave propagation method. The bolt fastening condition is adjusted by torque wrench. In order to estimate the damage condition numerically, three damage indices, impedance peak frequency shift ${\Delta}F$, peak amplitude ratio $\delta$ and quality factor ratio $\gamma$, are proposed in this paper. Furthermore, an assessment method is described for estimation of the damage by using these three damage indices.

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Singlet-Triplet Reactivity of 1-Methyl-2-Cyclohexenyl Aryl Ketones : Racemization vs 1,3-Acyl Shift in the Excited States

  • Woo Ki Chae;Mi Young Chae;Mi Kyung Park;Chung Hee Lee;Eun Hee You
    • Bulletin of the Korean Chemical Society
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    • 제11권3호
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    • pp.241-244
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    • 1990
  • The photochemistry of 1-Methyl-2-cyclohexenyl aryl ketones (phenyl ketone 7a, p-toluyl ketone 7b, biphenyl ketone 7c and -naphthyl ketone 7d) is reported. The aryl ketone 7a, 7b and 7c undergo photo-racemization with efficiencies of 0.75, 0.79 and 0.76 respectively on direct irradiation. Direct irradiation of the ketone 7d, however, undergoes 1,3-shift with an efficiency of 0.02. Triplet states are responsible for the racemizations and singlet state is responsible for 1,3-shift as in general. The ketone 7a, 7b and 7c are good example of a few ${\beta},{\gamma}$-unsaturated ketones which undergo efficient intersystem crossing on direct irradiation.

THE CORONA THEOREM FOR BOUNDED FUNCTIONS IN DIRICHLET SPACE

  • Nah, Young-Chae
    • 충청수학회지
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    • 제10권1호
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    • pp.141-146
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    • 1997
  • In this paper we prove that the corona theorem for the algebra $H^{\infty}(D){\cap}D(D)$. That is, we prove that $\mathcal{M}{\setminus}{\overline{D}}$ is an empty set where $\mathcal{M}$ is the maximal ideal space of the given algebra.

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