• Bulletin of the Korean Chemical Society
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• v.13 no.2
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• pp.173-176
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• 1992

The spectroscopic studies of the 5,7-dimethoxycoumarin(5,7-DMC) and 4,5',8-trimethylpsoralen(TMP) and the conformational stability of 5,7-DMC-thymidine, 4,5',8-TMP-thymine were carried out by the CNDO/S and molecular mechanics calculation. Theoretical transition energies and direction of polarizations calculated by the CNDO/S method have been used for the interpretation of the observed results. The calculated absorption spectra of 5,7-DMC are qualitatively similar to experimental ones with their characteristic visible bands. MM2 force field calculation on the possible $C_4-cyclophotoadducts$ formed between 5,7-DMC and thymidine through a cycloaddition. of $C_3$, $C_4$ bond of 5,6-DMC to $C_5$, $C_6$ bond of thymidine showed the most stable photocycloadduct to have the anti-head to tail configuration. The major photoadduct of 4,5',8-TMP-thymine has the cis-anti configuration.

• Applied Chemistry for Engineering
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• v.32 no.1
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• pp.10-14
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• 2021

mCherry is one of the well-understood red fluorescent proteins which has a similar tertiary structure as GFPs, but pH resistant due to the lack of hydrogen bond network. Whereas mCherry-I202T showed far-red fluorescence and also pH sensitive property because of the additional hydrogen bond formed by substituting Ile of 202 amino acid sequence on mCherry with Thr. In order to verify the pH sensitive characteristic of mCherry-I202T owing to the extension of hydrogen bond, UV-vis spectrum was measured over the range of acidic to basic pH. We also demonstrate further possibilities of applying mCherry-I202T as a pH sensor.

• Computers and Concrete
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• v.9 no.1
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• pp.35-50
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• 2012

The 2D representative volume element (RVE) for softening quasi-brittle materials like concrete is determined. Two alternative methods are presented to determine a size of RVE in concrete subjected to uniaxial tension by taking into account strain localization. Concrete is described as a heterogeneous three-phase material composed of aggregate, cement matrix and bond. The plane strain FE calculations of strain localization at meso-scale are carried out with an isotropic damage model with non-local softening.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.35-36
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• 2006

Excited-state intramolecular proton transfer (ESIPT) is a phototautomerization occurring in the excited states of the molecules possessing a cyclic intramolecular or solvent-bridged hydrogen bond. Recently, we have developed novel ESIPT chromophores, molecules, dendrimers and polymers which show very high fluorescence quantum efficiency combined with the characteristic features of optical switching, fluorescence patterining, lasing, and electroluminescence. Broad overview of these topics will be given in this talk.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.35-36
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• 2010

This research investigated the bond characteristic by lap splice experimental which has change relative area on rib variation of reinforcing bar. As a result has similar load-deflection curve with existing experiment, Maximum yield strength and displacement is increase.

• Proceedings of the KWS Conference
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• 2004.05a
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• pp.197-199
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• 2004

용접성은 모재의 조직과 기계적 성질 및 Bond 부와 열영향부의 조직과 기계적 성질의 관계로 평가된다. 탈소 함량이 높은 레일강의 경우 용접을 하고 나면 열영향부에 마르텐사이트와 같은 취약조직을 형성하여 경도 값이 높아지고 인성이 저하되어 균열발생 가능성이 높아진다. (중략)

• The Journal of Natural Sciences
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• v.16 no.1
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• pp.129-141
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• 2005

The equilibrium geometry, adiabatic electron affinity, harmonic vibrational frequencies, and infrared intensities of 1,4,6,9-Tetra chlorinated dibenzo-$\rho$-dioxin anion have been studied using B3LYP method. The local minimum conformation is found to be twisted form with $D_2$ symmetry. The predicted adiabatic electron affinity is 0.54 eV. The predicted inversion barrier between twisted and planar conformers was 0.9 kcal/mol, thus we expect that experimentally observed structure seems to be planar. the characteristic IR band of 1,4,6,9-TCDD anion appears at 1510 $cm^4$, which is a benzene ring skeleton vibration mode related with CaCb and C2C3 bond. this characteristic band could be sued for identication of 1,4,6,9-TCDD anion.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2003.11a
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• pp.53-58
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• 2003

Concrete structures move wholly with concrete and rebar, so they endure external force, but recently the embedded rebar in concrete has been corroded by environmental, physical and chemical factors, the embedded rebar corrosion influences concrete structure to deteriorate structure capacity. To revaluate effect to deterioration of concrete structure according to corrosion of rebar, the researcher mostly examined into corrosion rebar and complex relation of concrete. In that there are flexural strength deterioration of corrosion concrete structure and the bond strength of concrete. But It has not sufficiently studied about physical characteristic of corrosion rebar itself. In this study I will compare specification of rebar through corrosion experiment with corrosion ratio of rebar according to diameter and revaluate. And will investigate the effect to strength characteristic of rebar according to corrosion ratio.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2003.05a
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• pp.53-58
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• 2003

Concrete structures move wholly with concrete and rebar, so they endure external force, but recently the embedded rebar in concrete has been corroded by environmental, physical and chemical factors. the embedded rebar corrosion influences concrete structure to deteriorate structure capacity. To revaluate effect to deterioration of concrete structure according to corrosion of rebar, the researcher mostly examined into corrosion rebar and complex relation of concrete. In that there are flexural strength deterioration of corrosion concrete structure and the bond strength of concrete. But It has not sufficiently studied about physical characteristic of corrosion rebar itself. In this study I will compare specification of rebar through corrosion experiment with corrosion ratio of rebar according to diameter and revaluate. And I will investigate the effect to strength characteristic of rebar according to corrosion ratio.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.3A
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• pp.207-214
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• 2011

Ultra High Performance Concrete (UHPC), which is characterized by its high strength and advanced ductile behavior that is much superior to those of convention concrete, is a useful material to make thinner and longer bridges. The precast segmental construction method utilizing UHPC has been mainly studied because cast-in-place UHPC is very difficult and complicate to be achieved. As a part of those research, the structural performance evaluation of different types of joint connection method for hybrid cable-stayed bridge utilizing UHPC by using nonlinear analyses is performed in this study. The bond stress at joint is obtained by section force analyses for a 600 m cable-stayed bridge deck, and compared with the required bond stress at joint. Analysis results show that the U Type connection and straight type connection resist the highest ultimate load and bond strength, respectively. In addition, all considered joint connection systems satisfy the bond performances at joint required in the final stage of cable-stayed bridge utilizing UHPC.