• Title/Summary/Keyword: Confined

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Surface Plasmon Enhanced Photoluminescence of Rhodamine B Confined in SBA15

  • Dinakaran, K.;Chandramohan, A.;Venkatesan, M.R.;Devaraj, S.;Devi, V.;Alagar, M.
    • Bulletin of the Korean Chemical Society
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    • v.32 no.11
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    • pp.3861-3864
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    • 2011
  • Rhodamine B dye (RB) has been introduced into the mesoporous silica (SBA15) and Ag anchored mesoporous silica by applying solution impregnation method. Surface treatment of SBA15 with 3-aminopropyltrimethoxysilane (APTMS) facilitates selective anchoring of the RB molecules on SBA15. The photoluminescence spectra of RB confined within SBA15 indicates higher emission intensity, than that of the RB solid, particularly in the presence of Ag nanoparticles. The significant enhancement in photoluminescence intensity is attributed to the local enhancement of the optical fields near the molecules by interactions with silver plasmons.

FTIR study of E7 liquid crystals confined to perfluorinated carboxylic acid treated cylindrical cavities of Anodisc membranes

  • Ha, Ki-Ryong;Ahn, Hee-Jun;Yoon, Sung-Kyoun;Lee, Dong-Ho;West, John L.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2004.08a
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    • pp.369-372
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    • 2004
  • Orientation of E7 liquid crystals(LCs) confined to 200 nm-diameter cylindrical cavities of Anodisc membranes are investigated by FTIR dichroism techniques. The cavity walls of the confining pores are chemically modified with different perfluorinated carboxylic acids (PCA, $C_nF_{2n+1}$COOH, n=3, 4, 5, 6). From the FTIR spectra of PCA treated alumina Anodsic membranes, we found the salt formation between -COOH group of PCA and Anodisc membrane. From the FTIR spectra of LC filled Anodisc membranes, we found abrupt alignment direction change of LC molecules between n=4 and 5 for 1 mM PCA treated Anodisc membranes, from parallel to perpendicular direction to the cavity walls. But 5mM PCA treated Anodisc membranes, alignment direction of LC molecules changed between n=3 and n=4, from parallel to perpendicular direction.

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A Study on the Flexural Behavior of R.C Columns Confined by Lateral Ties (띠철근으로 구속된 철근 콘크리트 기둥의 휨 거동에 관한 연구)

  • 조세용;양근혁;이영호;정헌수
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.10a
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    • pp.601-604
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    • 1999
  • The objective of this study is to investigate the flexural behavior of reinforced concrete columns confined by lateral ties. This test was carried on the twelve reinforced concrete columns, 200$\times$200$\times$800mm size. objected to flexure and constant axial loads. The main variables are concrete strength, the configuration of lateral ties and the amount of lateral ties. Test results indicated that steel configuration plays an important role in column behavior, and a proper configuration of lateral ties can be more ductile than the reduce of the space of lateral ties. By this experiment, the ductility of high-strength concrete columns designed on A.C.I Code is not adequate, and are concluded that the design of high-strength concrete column is executed by more lateral ties under high axial loads.

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Analysis of the Stress-Strain Relationship of Concrete Compression Members Strengthened by Composite Materials (고분자복합재료 보강 콘크리트 압축부재의 응력-변형률 관계 해석)

  • 이상호;장일영;김효진;나혁층
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.10a
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    • pp.717-720
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    • 1999
  • Recently, the fiber composite materials such as carbon fiber, glass fiber, or aramid, have been frequently used in strengthening reinforced concrete structures. The fiber composite materials typically have orthotropic characteristic and the strength changes significantly acording to the direction of fibers and the method of the lamination. In this study, an algorithm to estimate the stress-strain relationship of the composite materials which have different fiber directions and symmetric or non-symmetric lamination has been developed by using Tsai-Hill and Tsai-Wu failure criteria and progressive laminate failure theory. This algorithm has been implemented to several stress-strain models for the laterally confined concrete compression members such as Mander, Hosotani, and Nakatsuka. The evaluated stress-strain behaviors by the different models are discussed.

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Experiments and Analysis of Concrete Columns Confined with Lateral Reinforcements (횡구속된 콘크리트 기둥의 실험 및 해석)

  • 송하원;최동휴;변근주;김기수
    • Magazine of the Korea Concrete Institute
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    • v.10 no.2
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    • pp.167-178
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    • 1998
  • 횡방향철근에 의하여 적절히 구속된 콘크리트 기둥은 강도증가 및 연성의 확보면에서 유리하다. 본 연구의 목적은 횡방향철근에 의하여 구속된 코아콘크리트의 크기,횡방향철근의 간격비 및 체적철근비 등의 변화에 따른 콘크리트 기둥의 극한강도를 포함한 최대하중 이전의 거동 및 최대하중 이후의 거동을 실험적, 해석적으로 고찰함으로써 콘크리트 기둥의 구속효과정도를 규명하려는데 있다. 본 연구에서는 횡구속된 콘크리트 기둥모형의 압축재하실험을 수행하였으며, 최대하중 이전의 거동에 대하여 연속체적 파괴와 소성을 고려한 3차원 모델링을 통한유한요소해석을 실시하였다. 또한 횡구속된 콘크리트 기둥의 변형률국소화 모델에 의한 파괴해석을 통하여 구속된 콘크리트 기둥의 최대하중 이후의 거동을 재현하였다. 해석결과는 압축재하실험의 결과와 비교, 분석되었으며, 이에 따른 구속효과를 규명하였다.