• 청정기술
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• 제29권2호
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• pp.79-86
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• 2023

Ru-MACHO-BH 촉매는 α, β-불포화 알데히드 화합물들의 카르보닐기(carbonyl group)만을 선택적으로 수소화 반응을 수행할 수 있다. 그러나 α, β-불포화 알데히드의 수소화 반응은 불균일 딜즈-앨더 반응을 수반하여 부산물인 이합체를 다량 생성한다. 본 연구에서는 Ru-MACHO-BH (Carbonyl hydrido (tetrahydroborato) [bis (2-diphenyl phosphino ethyl) amino] ruthenium(II)) 촉매를 이용하여, α, β-불포화 알데히드의 한 종류인 메타아크릴 알데히드(methacryl aldehyde) 화합물의 카르보닐기만 선택적으로 수소화 반응을 시켜 메타아릴 알코올(methallyl alcohol)을 합성하며, 동시에 2가 알코올을 부반응 억제제로 적용하였다. 이 결과는 모노 에틸렌 글리콜(mono ethylene glycol)이 이합체의 생성을 현저히 저감 시킬 수 있음을 보여주고 있다. 이러한 결과를 바탕으로 비닐기의 화학적 상호작용을 효과적으로 억제할 수 있는 하이드로퀴논을 사용하여 메타아크릴 알데히드에 존재하는 비닐기의 이합체 형성을 효과적으로 억제할 수 있었으며, 결국 메타아크릴 알데히드의 전환율을 상승시킬 수 있었다. 최종적으로, 고가의 귀금속 균일촉매인 Ru-MACHO-BH의 투입량을 1/10로 줄인 상태에서 원하는 생성물인 메타아릴 알코올의 선택도는 약 90% 이상, 수율은 약 80% 이상을 확보할 수 있었다. 이 결과는 수율 감소를 최소화하는 동시에 고가의 촉매 사용량을 저감하여 경제성을 향상시킬 수 있는 방법을 찾을 수 있게 하였다.

• Journal of Photoscience
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• 제2권2호
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• pp.95-98
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• 1995

The photodimers with cyclobutane rings and C$_2$ symmetry, derived from coumarin (syn, head to tail and anti, head to head) have been calculated by PM3-UHF-CI and Molecular Mechanics force field. The photocycloaddition to coumarin and 5,7-dimethoxycoumarin(DMC) dimers were deduced to be formed by their preferable frontier orbital interactions and via more stable cycloaddition by the C$_3$, C$_4$ bond. These results are consistent with the coumarin dimer model that the theoretical C$_4$-photocyclodimer of coumarin is predicted much more than the experimental C$_4$-photocyclodimer.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 1998년도 한국우주과학회보 제7권1호
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• pp.23.1-23
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• 1998

No Abstract.See Full-text

• EDISON SW 활용 경진대회 논문집
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• 제6회(2017년)
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• pp.11-15
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• 2017

We present a study of transition metal compounds using density functional theory (DFT), and density-corrected density functional theory(DC-DFT). By replacing the self-consistent density with that obtained from Hartree-Fock calculation, i.e., HF-DFT, the abnormality driven by self-interaction error is removed in several important cases. We discuss when and how HF-DFT works by examining 3d orbital dimers using approximate functionals and by comparing the results from self-consistent-DFT and HF-DFT with experimental values.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2002년도 봄 학술발표논문집 Vol.29 No.1 (B)
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• pp.604-606
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• 2002

본 논문에서는 3차원 영상의 생성 원리와 3차원 영상 모드 그리고 기존의 3차원 영상 재생 장치를 분석하였다. 3차원 영상 모드에는 interlace page-flipping, sync-doubling 모드가 있으며, LCD(Liquid Crystal Display) shutter glasses를 이용한 3차원 영상 재생 장치의 동작 원리 및 파형을 분석하였고 현 재생 장치의 장. 단점을 논하였다 이 장비는 심한 flicker를 유발하였고, 완전한 3차원 입체 영상의 효과를 얻을 수 없었다. 마지막으로 LCD 모니터용 3차원 영상 재생 장치의 필요성과 향후 연구 방향을 제시하였다.

• Bulletin of the Korean Chemical Society
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• 제30권7호
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• pp.1634-1636
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• 2009

• Macromolecular Research
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• 제8권2호
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• pp.53-58
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• 2000

Stabilities and structures of resorcinol formaldehyde resins (RF resins) and their dependence on solvent were studied by molecular mechanics and molecular dynamics. Dimers to decamers of the RF resins in the conditions of dielectric constant = 1.00, 21.01, 36.64, and 80.10 were calculated. The average distance between oxygen atoms in 1-hydroxyl groups of adjacent resorcinols of the resins became longer with increased dielectric constant of the environment. The number of intramolecular hydrogen bonds of the resins decreased by increasing the dielectric constant of the environment. The RF resin structure on the surface of fabric or steel cord was explained based on the present calculation.

• Bulletin of the Korean Chemical Society
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• 제2권1호
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• pp.8-11
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• 1981

A new potential function based on spectroscopic results for diatomic molecules is presented and applied to the hydrogen bonding systems. The potential energy of interaction is supposed to have electrostatic, polarization, dispersion, repulsion and effective charge-transfer contributions. Estimates of the effective charge-transfer quantity have been made based on the average charge of the proton donor and the acceptor atoms. For dimers such as water, methanol, acetic acid and formic acid, the vibrational stretching frequencies and dimerization energies are calculated and dicussed in connection with Badger-Bauer rule.

• Journal of Photoscience
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• 제9권2호
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• pp.221-224
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• 2002

Carcinogenesis can be theoretically divided to intiation step and promotion step. Intiation associates with genetic alterations including p53 tumor suppressor gene and ras oncogene. Promotion involves in clonal expansion of of an initiated cell by epigenetic mechanism, mainly through signal transduction and gene expression. Ultraviolet light (UV) acts as both initiator and promoter. Initiation is closely related with DNA damage induced by UV, including cyclobutane pyrimidine dimers, (6-4) photoproducts and 8-hydroxy-2'-deoxyguanosine. Cyclobutane pyrimidine dimers and (6-4) photoproducts are directly induced by UV, while 8-hydroxy-2'-deoxyguanosine is induced indirectly by the reactive oxygen species. Because initiation is an irreversal genetic event, while promotion is a reversal and epigenetic event, to know the molecular mechanisms of tumor promotion in UV-carcinogenesis is crucial to develop preventive medicine and suppress UV-carcinogenesis. Because ROS is also involved in signal transduction of the cell, anti-oxidant could be the good candidate of anti-promoting agent. Here, we describe the suppressive effect of UV-carcinogenesis by various anti-oxidant including olive oil. In addition, we discuss about the mechanism of UVB-induced expression of cyclooxygenase-2, which might be a representative molecule involved in promotion of UV-carcinogenesis.

• Journal of Photoscience
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• 제9권2호
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• pp.479-481
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• 2002

UV-induced DNA damage causes cell killing and mutations leading to carcinogenesis. In normal human cells, UV damage such as cyclobutane pyrimidine dimers (CPDs) and primidine-prymidone (6-4) photoproducts are mainly repaired by nucleotide excision repair mechanism. The molecular processes have been well characterized recently. To know the influence of mitochondrial genome on the nucleotide excision repair mechanism against CPDs, we comparatively examined the production of CPDs by UVC irradiation and their repair kinetics in human cells completely lacking mitochondrial DNA (mtDNA) and the parental HeLa S cells. Whole DNA extracted from the cells exposed to UVC was treated with T4-endonuclease V to break the phosphodiester bond adjacent to CPDs. The DNA was electrophoresed in a denaturing agarose gel, which was visualized by ethidium bromide staining. The relative amount of CPDs was determined by image analysis using NIH Image software. MtDNA- less (rho-O) cells were apparently more sensitive to UVC than HeLa S cells, while the level of induction of CPDs in rho-O and HeLa cells was comparable. The repair of CPDs was less efficient in rho-O cells compared with HeLa cells. The residual amount of CPDs after 24-h repair was larger in rho-O cells than in HeLa cells where more than 90 % of CPDs were repaired by then. The non-repaired CPDs would lead to apoptosis in rho-O cells. These results suggest that mitochondrial genome may contribute to some ATP-dependent steps in nucletide excision repair by supplying sufficient ATP which is generated through a respiratory chain in mitochondria.