• 제목/요약/키워드: SamCho

검색결과 1,040건 처리시간 0.03초

축소모델에서 강체모드 분리와 급수전개를 통한 준해석적 민감도 계산 방법 (A REFINED SEMI-ANALYTIC DESIGN SENSITIVITIES BASED ON MODE DECOMPOSITION AND NEUMANN SERIES IN REDUCED SYSTEM)

  • 김현기;조맹효
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2003년도 춘계학술대회
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    • pp.491-496
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    • 2003
  • In sensitivity analysis, semi-analytical method(SAM) reveals severe inaccuracy problem when relatively large rigid body motions are identified for individual elements. Recently such errors of SAM resulted by the finite difference scheme have been improved by the separation of rigid body mode. But the eigenvalue should be obtained first before the sensitivity analysis is performed and it takes much time in the case that large system is considered. In the present study, by constructing a reduced one from the original system, iterative method combined with mode decomposition technique is proposed to compute reliable semi-analytical design sensitivities. The sensitivity analysis is performed by the eigenvector acquired from the reduced system. The error of SAM caused by difference scheme is alleviated by Von Neumann series approximation.

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강체모드분리와 급수전개를 통한 준해석적 민감도 계산 방법의 개선에 관한 연구(I) - 정적 문제 - (A Refined Semi-Analytic Sensitivity Study Based on the Mode Decomposition and Neumann Series Expansion (I) - Static Problem -)

  • 조맹효;김현기
    • 대한기계학회논문집A
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    • 제27권4호
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    • pp.585-592
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    • 2003
  • Among various sensitivity evaluation techniques, semi-analytical method(SAM) is quite popular since this method is more advantageous than analytical method(AM) and global finite difference method(FDM). However, SAM reveals severe inaccuracy problem when relatively large rigid body motions are identified fur individual elements. Such errors result from the numerical differentiation of the pseudo load vector calculated by the finite difference scheme. In the present study, an iterative method combined with mode decomposition technique is proposed to compute reliable semi-analytical design sensitivities. The improvement of design sensitivities corresponding to the rigid body mode is evaluated by exact differentiation of the rigid body modes and the error of SAM caused by numerical difference scheme is alleviated by using a Von Neumann series approximation considering the higher order terms for the sensitivity derivatives.

고속액체크로마토그라피에 의한 음양곽 중 Icariin의 정량 (Determination of Icariin in Epimedii Herba by High Performance Liquid Chromatography)

  • 신국현;강삼식;정순간;조의환
    • 생약학회지
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    • 제20권1호
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    • pp.21-24
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    • 1989
  • A new method for quantitative determination of icariin in Epimedii Herba by high performance liquid chromatography was established. A reversed-phase system with $a\;{\mu}Bondapak\;C_{18}$ column using methanol in water(15% to 70%, gradient elution) as a mobile phase was developed. Icariin and spinosin as an internal reference were detected at 350 nm and the analysis was successfully carried out within 30 min.

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Preparation of Iron Catalytic Layer onto Functionalized Silicon Substrate for Synthesis of Carbon Nanotubes

  • Adhikari, Prashanta Dhoj;Cho, Jumi;Park, Chong-Yun
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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    • pp.611-611
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    • 2013
  • In this study, iron oxide nanoclusters layer (Nc) was prepared onto functionalized silicon substrate by wet method. The amine-terminated SAM fabricated on silicon substrate (APTMS/Si) was carried out by UV-treatment and immersed into the FeCl3/HCl aqueous solution. Then, Nc were immobilized onto oxidized SAM silicon substrate (SAMs/Si) through electrostatic interaction between cationic Nc and anionic SAMs/Si. This catalytic layer (Nc/SAMs/Si) was used to grow carbon nanotubes (CNTs). The characterization results clearly show that the well-graphitized CNTs were synthesized by using functionalized silicon substrate as a template having appropriate density of catalyst. These consequences show that SAM containing template is important to achieve the effective layer of catalyst to synthesize CNTs.

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임프린트를 위한 자기조립단분자 이형코팅 (Self-assembled moolayers as anti-stiction coating for imprint)

  • 이상문;나승현;조재춘
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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    • pp.219-219
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    • 2007
  • Ni stamper위에 100nm의 Si 코팅후 자기조립 단문자막(SAM)을 액상 코팅방식으로 형성 하였고, 내구성 및 열적 안정성을 검증하기 위해 반복적인 이형 및 압력인가test가 실시하였다. 20 회 이상의 이형실험을 통해 열적, 기계적 안정성을 확인하고, 접촉각 측정을 통해 이형특성의 안정성도 고찰하였다. 이를 Imprint공법을 적용 fine pattern의 구조물을 얻을수 있었다. SAM코팅은 TRICHLOROSILANE을 사용하였으며 Hexane과 1000:1의 비율로 섞어서 stirrer에서 mixing하는 방식을 사용했으며, UV-ozone처리를 통한 이형성 제거 효과도 관찰하였다.

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스펙트럴 요소 모델을 이용한 스펙트럴 해석법 (A SPECTRAL ANALYSIS METHOD FOR SPECTRAL ELEMENT MODELS)

  • 조주용;윤덕기;황인선;이우식
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2005년도 추계학술대회 논문집
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    • pp.409-414
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    • 2005
  • In the literatures, the FFT-based SAM has been well applied to the computation of the steady-state responses of discrete dynamic systems. In this paper, a fast fourier transforms (FFT)-based spectral analysis method (SAM) is proposed fur the dynamic analysis of spectral element models subjected to the non-zero initial conditions. However, the FFT-based SAM has not yet been developed for the continuous systems represented by the spectral element model.

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