• Bulletin of the Korean Chemical Society
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• 제31권10호
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• pp.2806-2808
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• 2010

The structure of 3-aminophenol $(CO_2)_1$ cluster was computationally studied both in the ground and the lowest singlet excited electronic states. The ground state structure and binding energy of the cluster was investigated using the second-order M$\ddoot{o}$ller-Plesset perturbation theory (MP2) at the complete basis set (CBS) limit. The excited state geometry of the cluster was obtained at the second-order approximate coupled cluster (CC2) level with cc-pVDZ basis set, and the $S_0-S_1$ absorption spectrum was simulated by calculating Franck-Condon overlap integral. The ground state geometry of the global minimum with a very high binding energy of 4.3 kcal/mol was found for the cluster, due to the interaction between amino group and $CO_2$ in addition to the strong $\pi-\pi$ interaction between the aromatic ring and $CO_2$. The excited state geometry shows a very big shift in the position of $CO_2$ compared to the ground state geometry, which results in low intensity and broad envelope in the Franck-Condon simulation.

• Bulletin of the Korean Chemical Society
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• 제33권12호
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• pp.4079-4083
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• 2012

The mechanism of the cycloaddition reaction between singlet state dichlorosilylene germylidene ($Cl_2Si=Ge:$) and acetone has been investigated with B3LYP/6-$31G^*$ and B3LYP/6-$31G^{**}$ method, from the potential energy profile, we predict that the reaction has one dominant reaction pathway. The presented rule of the reaction is that the two reactants firstly form a Si-heterocyclic four-membered ring germylene through the [2+2] cycloaddition reaction. Because of the 4p unoccupied orbital of Ge atom in the Si-heterocyclic four-membered ring germylene and the ${\pi}$ orbital of acetone forming a ${\pi}{\rightarrow}p$ donor-acceptor bond, the Si-heterocyclic four-membered ring germylene further combines with acetone to form an intermediate. Because the Ge atom in the intermediate hybridizes to an $sp^3$ hybrid orbital after the transition state, then, the intermediate isomerizes to spiro-heterocyclic ring compound involving Si and Ge (P4) via a transition state.

• 한국광학회지
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• 제16권2호
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• pp.146-151
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• 2005

PMMA에 pyrromethene 597(PM597) 색소를 주입하여 고체 색소를 제작한 후 그 레이저 출력특성을 분석하였다. 펌핑 광원으로 Q-스위치 Nd : YAG 레이저의 제 2 고조파를 사용하여 발진 중심파장 585 nm에서 최대 광 변환효율 $76\%$를 얻었다. 광안정성을 증가시키기 위해 단일항 에너지 상태의 산소 제거제인 DABCO(1,4-diazabicyclo [2,2,2]octane)를 주입하여 반복율 4 Hz, 출력에너지 250 mJ, 100,000번 이상의 펄스 출력을 얻었다.

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2011년도 제45차 학술발표회
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• pp.41-41
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• 2011

The aims of this study were to examine the efficacy of phytochemicals of Rumex crispus as anti-oxidant and anti-browning agent. The bioactive properties of Rumex crispus as natural colorants were studied by total phenolic contents, DPPH radical scavenging, ABTS radical scavenging,lipid peroxidation, cell viability, singlet oxygen quenching and photoprotection effect. Among all of the results ($IC_{50}$: the concentration of various extracts required to exert 50% reducing effect), the higher activity of the extract was found in the ethyl acetate and butanol extracts. Anti-browning activity was evaluated by monitoring the change $L^*$, $a^*$, $b^*$ values and total color differences(${\Delta}E$). It was found that ethyl acetate and butanol extracts effectively inhibited browning in apple juice at a concentration below 0.3 mg/ml. Rumex crispus extracts used natural colorants could be of good resources as anti-oxidant and anti-browning agents. The results suggest that our study may contribute to the development of natural and functional materials with potential application to reduce oxidative damage.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 Techno-Fair 및 추계학술대회 논문집 전기물성,응용부문
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• pp.104-105
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• 2007

In this study, characteristics of silver ink-jet printing were investigated under various substrate treatments such as substrate heating, hydrophobic coating, and ultraviolet(UV)/ozone soaking. Fluorocarbon(FC) film was spin-coated on the polyimide (PI) film substrate to obtain a hydrophobic surface. Although hydrophobicity of the FC film could reduce the diameter of the printed droplets, the singlet images printed on the FC film surface showed irregularities in the pattern size and the position of the printed droplet along with droplet merging phenomenon. The proposed UV/ozone soaking of the FC film improved the uniformity of the pattern size and the droplet position after printing and substrate heating was very effective way in preventing droplet merging. By heating of the substrate after UV/ozone soaking of the coated FC film, silver conductive lines of 78-116 ${\mu}m$ line were successfully printed at low substrate temperatures of $40^{\circ}C$.

• Journal of the Optical Society of Korea
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• 제8권4호
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• pp.174-181
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• 2004

Various kinds of systems, that can do target recognition and position detection simultaneously by using infrared sensing detectors, have been developed. In this paper, the detection system TRSS (Thermal target Recognition by Spiral Scanning) adopts linear array shaped uncooled IR detector and uses spiral type fast scanning method for relative position detection of target objects, which radiate an IR region wavelength spectrum. It can detect thermal energy radiating from a 9 m-size target object as far as 200 m distance. And the maximum field of a detector is fully filled with the same size of target object at the minimum approaching distance 50 m. We investigate two types of lens systems. One is a singlet lens and the other is a doublet lens system. Every system includes one aspheric surface and free positioned aperture stop. Many designs of F/1.5 system with ${\pm}5.2^{\circ}$ field at the Efl=20, 30 mm conditions for single element and double elements lens system respectively are compared in their resolution performance [MTF] according to the aspheric surface and stop position changing on their optimization process. Optimum design is established including mechanical boundary conditions and manufacturing considerations.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2007년도 Proceedings of The Convention
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• pp.93-114
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• 2007

Vaccinium uliginosum L. (VU) is a flowering plant in the genus Vaccinium has berry fruit. This study was performed to investigate the effect of water extract of Vaccinium uliginosum L. and fractions on inhibition of melanogenesis and wrinkle formation. One hundred grams of the Vaccinium uliginosum L. was extracted with 2,000 mL of water ($90^{\circ}C$, 16h, 2 times). The water extracts were lyophilized and stored at $4^{\circ}C$ until used. Vaccinium uliginosum L. extracts showed scavenger activities on DPPH radical, superoxide anion radical, hydroxyl radical, hydrogen peroxide and singlet oxygen radical, dose dependently. And VU extract and fractions reduced melanin contents on B16F10 melanoma and inhibited the expression of melanogenesis-related proteins, tyrosinase, tyrosinase-related protein (TRP-1) and dapachrometa utomerase (Dct, TRP-2). Moreover VU extract and fractions stimulated procollagen production and inhibited MMP-1 production in human fibroblast. And it decreased degree of wrinkle formation in hairless mouse skin that induced by DVB irradiation for 9 weeks. From the above results, it is possible that Vaccinium uliginosum L. may be developed to be the health functional food and functional cosmetics that have anti-melanogenesis and anti-wrinkle effect.

• Journal of Photoscience
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• 제9권3호
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• pp.41-43
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• 2002

PDT-mediated cyototoxicity basically depends on the penetrated light-dose into the tumor tissue. This limits the efficiency of PDT to the superficial tumor region typically less than 1 cm. The localized photochemical generation of reactive oxygen species, including singlet oxygen is known to increase expression of assortment of early response genes including heat shock protein. In order to increase PDT cytotoxicity in the treatment of solid tumor, it is desirable to combine PDT with other therapeutic effects. In this preliminary study we evaluated enhanced cytotoxicity from the PDT-mediated expression of thymidine kinase in a transfected tumor cell line. Two types of photo sensitizers, a hematoporphyrin derivative(Photogem, Russia) and aluminium sulphonated phthalocyanine(Photosense, Russia) were used to evaluate the overexpression of hsp-70 in PDT-treated cell. Transient increase of hsp-70 was observed at 6-8 hrs later following irradiation in the photosense-treated cell whereas it was not observed in Photogem-treated cell. In the presence of ganciclovia, transfected cell showed a 17％ increase in the cytotoxicity compared to the PDT only cell.

• 한국염색가공학회지
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• 제10권3호
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• pp.20-28
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• 1998

Natural indigo colorants were prepared by extraction of polygonum tintorium which was harvested just in the blooming season(in the late of July). The components were analyzed by TLC and HPLC, and its structures were analyzed by FT-IR, EI-mass and NMR. The dyeing mechanism and fermentation conditions were investigated. Its colour fastness was studied as well. The results obtained are summarized as follows ; The natural indigo powder was dissolved in DMSO and developed in eluent, $CHCl_3/CH_3CN(8.5:1.5v/v)$ by means of TLC for its quality analysis. It was segregated into indirubin as il red colour and indigo as a blue colour. In case of HPLC analysis, the retention times of indirubin and indigo were 7.442 and 6.543, respectively. FT-IR spectrum of indirubin showed a peak for NH residue between 3200 and $3300cm^{-1}.^1H-NMR$ spectrum for indigo displayed AA'BB' spin system caused by indole structure between 6.5 and 7.7ppm of H4, 5, 6 and 7, and -NH proton for indirubin showed an singlet between 10.88 and. 11.0ppm. EI-mass spectrum of indigo an d indirubin both disclosed their molecular size as 262 and it implies that these two substances are isomer.

• 한국응용과학기술학회지
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• 제19권2호
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• pp.97-102
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• 2002

Recently, the phosphorescent organic light-emitting devices (OLEDs) have been extensively studied for their high internal quantum efficiency. In this study, we synthesised several phosphorescent metal complexes, and certified their composition using NMR. We also investigated the characteristics of the phosphorescent OLEDs with the green emitting phosphor, $Ir(ppy)_{3}$. The devices with a structure of indium-tin-oxide(ITO)/N,N'-diphenyl-N,N'-(3-methylphenyI}-1,1'-biphenyl-4,4'-diamine (TPD)/metal complex doped in host materials/2,9-dimethyl-4,7-diphenyl-l,10-phenanthroline(BCP)/tris (8-hydroxyquinolinato) Aluminum($Alq_{3}$)/Li:Al/Al was fabricated, and its electrical and optical characteristics were studied. By changing the doping concentration of tris(2-phenylpyridine)iridium ($Ir(ppy)_{3}$), we fabricated several devices and investigated their characteristics.