• 약학회지
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• 제35권5호
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• pp.427-431
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• 1991

A flavonoidal glycoside was isolated from the whole plant of Hydrocotyle japonica(Um belliferae) and identified as quercetin-3-O-$\beta$-D-galactoside quercetin-3-O-$\beta$-D-(hyperoside) (C$_{21}H_{20}O_{12}$.1/3 $H_2O$, yellow needle crystal, m.p. $249~250^{\circ}$, $[\alpha]^{28}_D^{\circ}$$-65.94^{\circ}$ in pyridine) by physicochemical properties and spectroscopic evidences(UV, IR, NMR and Mass etc., in comparison with authentic sample.

• Bulletin of the Korean Chemical Society
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• 제18권2호
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• pp.198-203
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• 1997

Two different carbazolylnitrostilbene chromophores with second-order nonlinear optical (NLO) activity were newly synthesized by the reaction of 9-(2-hydroxyethyl)-9H-carbazol-3-carbaldehyde with 4-nitrophenylacetonitrile or 4-nitrophenylacetic acid. The NLO monomers were obtained by reaction of these chromophores with methacryloyl chloride. The side-chain nonlinear optical polymers were synthesized by the copolymerization of NLO monomer with methylmethacrylate using a free radical initiator. The chemical structures of the polymers were identified by spectroscopic means and the polymer properties such as molecular weight, Tg, solubility, UV-visible absorption, and second-harmonic generation (SHG) coefficients were investigated.

• Bulletin of the Korean Chemical Society
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• 제8권3호
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• pp.206-211
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• 1987

The photoreaction of 5,7-dimethoxycoumarin with adenosine has been carried out in a dry film state. The mixture of DMC and adenosine was irradiated with 350 nm UV light and two major products were isolated. The structure was determined by various spectroscopic measurements involving $^{13}C$ nuclear magnetic resonance and fast atom bombardment mass spectrometry. These addition products were produced by covalent bond formation between the pyrone ring at carbon 3 or 4 and the sugar ring moiety of adenosine at carbon 5'.

• 천문학회보
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• 제35권2호
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• pp.41.2-41.2
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• 2010

We present ultraviolet (UV) properties of dwarf galaxies in the Ursa Major cluster comparing with those in the Virgo cluster. We have constructed SDSS DR7/GALEX GR5 matched optical/UV catalog for dwarf galaxies with various morphologies in these two clusters. Membership of galaxies belonging to the Ursa Major cluster was made by hierarchical grouping method using SDSS spectroscopic data. We classified morphologies of dwarf galaxies using the combination of visual inspection of the images and spectral features returned from SDSS data. In contrast to the case of the Virgo cluster, majority of dwarf galaxies in the Ursa Major cluster lies in the blue cloud of the UV color-magnitude relations (CMRs) implying strong recent or on-going star formation. We discuss the cluster environment on the star formation history and evolution of dwarf galaxies.

• 한국광물학회지
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• 제22권2호
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• pp.81-86
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• 2009

변색 효과를 보이는 6종의 보석들을 대상으로 UV-Vis 분광분석과 Photoluminescence에 의한 발광 및 형광 특성을 조사하였다. 514 nm Ar이온 source로 PL을 측정한 결과 발광 피크의 모양이 다르게 나타났고 같은 천연과 합성 보석에서는 동일한 피크가 나타났다. 이들 발광 및 형광 특성은 보석들의 결정 구조와 관련이 있음을 관찰할 수 있었다. 325 nm He-Cd source에 의한 형광 조사에서는 합성 알렉산드라이트와 합성 칼라체인지 사파이어 그리고 천연 알렉산드라이트에서 강한 형광이 나타났고 이를 PL 피크로 확인하였다.

• Macromolecular Research
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• 제9권6호
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• pp.327-331
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• 2001

A new soluble photosensitive poly(amide-co-imide) containing p-phenylenediacryloyl moiety was synthesized and its photoreactivity was characterized. The copolymer was synthesized fromp-phenylenediacryloyl chloride, 4,4-(hexafluoroisopropylidene)diphthalic anhydride and two equivalents of bis(4-aminophenyl) ether in NMP with a subsequent chemical imidization of the resulting poly[amide$\xi$ο-(amic acid)] by acetic anhydride and pyridine. The structure and thermal properties of the polymer were characterized by spectroscopic methods and thermal analyses. The polymer was stable up to 350$\^{C}$, showed good solubility in polar aprotic solvents, and became insoluble after UV irradiation due to the[2+2] cycloaddition of phenylenediacryloyl moiety. Photoreactivity of the polymer was investigated in solution or as a film with respect to the various exposure conditions by UV/Vis spectroscopy. The photosensitivity was noticeably increased with the irradiation temperature, especially in the presense of photosensitizer. The reason for the increased sensitivity was speculated based on the flexibilization of main chain at elevated temperature. Exposure characteristic curves were obtained from the gel fraction experiments after UV irradiation. The sensitivity and contrast at 160$\^{C}$ were measured to be 293 mJ/㎠ and 1.64, respectively.

• Bulletin of the Korean Chemical Society
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• 제27권3호
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• pp.368-372
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• 2006

The cobalt titanate, $CoTiO_3$ nanoparticles have been prepared by calcinations of precursor obtained from a mixture of $TiO_2$ and $Co(OH)_2$ in aqueous cetyltrimethylammonium bromide (CTAB) solution. The nanoparticles were investigated with X-ray powder diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and thermogravimetric/differential thermal analysis (TGA/DTA) to determine the crystallite size and the phase composition. The spectroscopic characterizations of these nanoparticles were also done with UV-Vis spectroscopy and FT-Raman spectroscopy. XRD patterns show that $CoTiO_3$ phase was formed at calcinations temperature above 600 ${^{\circ}C}$. UV-Vis absorption spectra indicate that the $CoTiO_3$ nanoparticles have significant red shift to the visible region (400-700 nm) with $\lambda_{max}$ = 500 nm compared to pure $TiO_2$ powder ($\lambda_{max}$ = 320 nm). The new absorption peaks (absorption at 696, 604, 520, 478,456, 383, 336, 267, 238, 208 $c m ^{-1}$), which were not appeared in FT-Raman spectra of P-25, also confirm the formation of Ti-O-Co bonds at above 600 ${^{\circ}C}$ and just not the mixtures of titanium dioxide with cobalt oxides.

• 한국진공학회지
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• 제17권2호
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• pp.138-147
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• 2008

RF 스퍼터링 시스템을 이용하여 $SiO_2/TiO_2/ZrO_2$ 광대역 반사방지막을 단계별로 제작하였고, 분광타원계와 $UV-V_{is}$ 분광광도계를 이용하여 박막의 두께, 굴절률 및 투과율 스펙트럼을 300$\sim$900nm의 파장 영역에 걸쳐 측정 및 분석하였다. 측정 및 분석된 박막의 두께, 굴절률 및 투과율 스펙트럼을 설계값과 비교 평가한 결과 각층의 두께, 굴절률의 차이에 따른 투과율의 변화를 분석할 수 있었고, 박막의 두께보다는 굴절률과 굴절률의 분산형태가 투과율의 변화에 더 크게 기여함을 알 수 있었다.

• 대한화학회지
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• 제22권4호
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• pp.239-244
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• 1978

Stilbene 유도체인 trans-1,2-bispyrazylethylene에 대한 분광학적 연구를 행하였다. 보통의 자외선 흡수스펙트럼에서는 $n{\rightarrow}{\pi}^*$ 흡수밴드는 에너지가 비슷한 ${\pi}{\rightarrow}{\pi}^*$ 흡수밴드에 가려져서 나타나지 않는데 2차 미분 스펙트럼과 저온(77˚K)에서의 스펙트럼으로 부터 $n{\rightarrow}{\pi}^*$ 흡수 밴드를 확인할 수가 있었다. 또한 ${\pi}{\rightarrow}{\pi}^*$ 흡수밴드들의 전이에너지를 PPP-SCF-CI MO 방법으로 계산한 결과 스펙트럼에서 얻은 값과 잘 일치했다. 형광스펙트럼, 형광편광스펙트럼, 그리고 PPP-SCF-CI MO 방법에 의한 계산으로부터 형광을 내는 상태는 $^1({\pi},\;{\pi}^*)$ 상태임을 알 수가 있었으며 이것은 형광에 대한 alkaline salt effect의 결과와 일치한다.

• 폴리머
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• 제31권2호
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• pp.153-159
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• 2007

생분해성 분자 날인 고분자는 바이오센서 약물 전달 등의 생의학적 분야에 적응이 가능하다. 그러므로, 본 연구에서는 생분해성 고분자인 $poly(\varepsilon-caprolactone)$ (PCL) 매크로머를 가교제로 사용하여 theophylline 분자 날인 고분자를 광중합을 통해 제조하고 물성을 조사하였다. PCL 매크로머는 말단에 아크릴기를 갖도록 합성하였으며 FT-IR과 $^1H-NMR$로 확인하였다. PCL 매크로머의 합성수율은 약 78 mol%였다. Theophylline의 제거 및 재결합 실험은 UV/Vis분광기를 이용하여 용액 내 theophylline의 농도를 확인함으로써 이루어졌다. Theophylline분자 날인 고분자의 생분해성 실험을 $37^{\circ}C$의 PBS 용액 내에서 진행한 결과 우수한 생분해성을 보였다.