• 한국전기전자재료학회논문지
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• 제29권1호
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• pp.35-39
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• 2016

In this research, we focused on the improvement of cy3 dye's characteristics for LCD color filter. Solubility and thermal stability are main characteristics of dyes for LCD color filter. We performed experiment to change counter cation of cy3 dyes with alkoxy substituent for these purposes. These cy3 dyes (1b~5b) were prepared through the synthetic procedure of three steps. The synthesized new cy3 dyes were charaterized by using NMR, FT-IR, UV/Vis spectroscopy, and TGA. These cy3 dyes showed purple color and maximum absorption wavelength (${\lambda}_{max}$) in the range of 578~590 nm in UV/Vis spectrum. We confirmed that solubility and thermal stability of cy3 dyes were dependent on the structure of counter cation. Cy3 dyes with alkoxy substituent have good solubility in organic solvents such as dichloromethane, methanol, and acetone. Especially, Cy3 dye with 4-nitrobenzyl counter cation (5b) gave excellent solubility characteristics.

• 한국전기전자재료학회논문지
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• 제26권7호
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• pp.528-533
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• 2013

We focused on the development of red azo colorants with high thermal stability and good solubility for LCD color filter in this research. For the synthesis of hybrid azo colorants, we used the couplers of aniline, naphthol and benzoimidazol functional group. The synthesized hybrid azo colorants were charaterized by using NMR, UV/visible spectroscopy, FT-IR, EA and TGA. They represented the maximum absorption wavelengths which are longer than 500 nm in UV/visible spectrum. So they were confirmed to be suitable for red colorants of LCD color filter. Azo compound (1a, 1b) with aniline functional group had good solubility in organic solvents such as acetone, methanol, chloroform and PGMEA. Moreover azo compounds (1c, 1d and 1e) with naphthol and benzoimidazolone functional group gave excellent thermal stability higher than $250^{\circ}C$ in TGA thermograms.

• Journal of Microbiology
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• 제33권3호
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• pp.239-243
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• 1995

Deinococcus radiophilus, an UV resistant bacterium seemed to contain three issoenzymes of catalase. Among them, the samllest and most abundant species in cell-free extract, catalase-3 which also exhibited peroxidase activity was purified to electrophoretic homogeneity (145-fold purification) by chromatographic procedures. Its molecular weight was 155 kDa composed of four 38 kDa subunits. The $K_{m}$ value of catalase-3 for H$\_$2/O$\_$2/ was approximately 0.5 mM. This enzyme showed a typical ferric heme spectrum with maximum absorption at 405 nm. Upon binding to cyanide, the 405 nm peak shifted to 420 nm. Catalase-3 was very sensitive to inhibitors of heme proteins, such as cyanide, azide and hydroxylamine. A ratio of A$\_$405/A$\_$28O/ was 0.5 Catalase-3 was active over a wide range of pH, between pH 7 and 10. The enzyme was rather heat-labile and partially sensitive to edthanol-chloroform treatment, but resistant to 3-amino-1, 2, 4-triazole. Catalase-3 of D. radiophilus, which is a bifunction catalatic peroxidatic enzyme seemed to share certain molecular properties with the typical catalase and the catalase-[roxidase along with its own unique features.

• 한국재료학회지
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• 제16권10호
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• pp.624-628
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• 2006

In this study, divalent europium-activated $NaCaPO_4$ green phosphor powders were prepared by the chemical synthetic method followed by heat treatment in reduced atmosphere, and the crystal structures, morphologies and photoluminescent properties of the powders were investigated by x-ray powder diffraction, scanning electron microscope and spectrometer for the first time. The effects of Ca/P and Na/Ca mole ratios on the final products were also investigated. The influences of input amount change of europium as the activator on the light emission intensity were studied, and the resulting concentration quenching phenomenon was observed. The optimized synthesis conditions obtained in this study were Ca/P mole ratio 1.2, Na/Ca mole ratio 3.0 and 4 mole%Eu. The peak wavelength was 505 nm for all the samples. The result of excitation spectrum measurement indicated that the excitation efficiency was high for the long-wavelength UV region. It was thus concluded that the samples prepared in this study can be successfully applied for the light-emitting devices such as LED excited with long-wavelength UV light sources.

• Bulletin of the Korean Chemical Society
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• 제21권1호
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• pp.101-104
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• 2000

Li-graphite intercalation compounds (GICs), synthesized at elevated temperature and pressure, were allowed to decompose spontaneously in the atmosphere. The decomposition processes were analyzed by of X-ray diffraction, DSC analysis, FT-IR measurements, UV/VIS spectrophotometry. The deintercalation reaction of the Li-GICs ceased after 6 weeks and only the residual compounds could be observed. A strong exothermic reaction was observed at 300 $^{\circ}C$ in thermal decomposition, and relatively stable decomposition curves were formed. A few endothermic curves have been observed at 1000 $^{\circ}C.$ After 6 weeks deintercalation reaction time of GICs, many exothermic and endothermic reactions were accompanied at the same time. In addition the reactions of the functional groups such as aromatic rings, nitrogen, $-CH_3$, $-CH_2$ etc. of GDIC obtained by the above reaction were confirmed by FT-IR spectrum. UV/VIS spectrophotometric measurement clearly shows the formation of a minimum energy value ($R_{min}$) for the compounds between Li-GICs as a starting material and Li-GDICs obtained until after 3 weeks of the deintercalation reaction, while they were no clear energy curves from 4 weeks of reaction time, because of the formation of the graphite structure, of high stages and of the Li compounds surrounding the graphite in the deintercalation reaction.

• 한국의류학회지
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• 제46권1호
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• pp.132-146
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• 2022

To explore the potential use of Ecklonia cava as a natural dye for textiles, silk fabric was dyed with Ecklonia cava extracted by hot water under varied conditions, including temperature, duration, dye concentration, mordanting, and pH adjustment. The fabric was also evaluated for fastness, sun-protective property, and deodorization. Ecklonia cava extract was estimated by FT-IR to have polyphenol as a main functional colorant in plants, while the existence of phlorotannins through the UV-spectrum method was also confirmed. The fabric was optimized for maximum dye uptake at a temperature of 80℃ for a duration of 50 minutes along all dye concentrations. The dyed fabric showed a hue of Yellow Red under all dyeing conditions while additional color tones, such as grayish and dark, were generated through mordanting and pH adjustment. Both good sun-protective properties and a positive deodorization rate were also recorded, with more than 20% (owf) Ecklonia cava extract on silk fabric. These results imply that Ecklonia cava has great potential to be used as an eco-friendly natural dye and in fashion goods with skin-health functions made of silk.

• Journal of Applied Biological Chemistry
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• 제66권
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• pp.106-113
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• 2023

Plant extracts have been studied due to their potential as photoprotective agents against UV and blue light exposure. Previous studies have revealed that several plant extracts have photoprotection capacities and synergistic effects with synthetic products. However, such results for pu'er tea and Curcuma longa L. have not been reported yet for a cosmetic formulation. Thus, the objective of this study was to evaluate photoprotection capacities of pu'er tea and C. longa L. extracts for a sunscreen compound. The pu'er tea extract improved sun protection factor value of 2-ethyl-hexyl methoxycinnamate (a synthetic sunscreen compound) by 46% and showed a high antioxidant capability that could help skin recover from photo-induced damage. C. longa L. extract also showed a potential to protect skin from blue light-induced damage because it not only had a maximum absorption peak at the blue light range, but also protected human fibroblasts from blue light-induced damage. The addition of both extracts shifted the critical wavelength of 2-ethyl-hexyl methoxycinnamate from 350 nm to 386 nm, giving it a broad-spectrum feature. Thus, pu'er tea and C. longa L. extracts may enhance the photoprotection ability of synthetic sunscreen products.

• Journal of Electrochemical Science and Technology
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• 제15권2호
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• pp.268-275
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• 2024

The study examined the electrogeneration of hypochlorite ions (ClO^-) via electrolysis of aqueous NaCl solutions using a dimensionally stable anode-type (DSA-type) electrode based on platinum and palladium oxides supported on titanium mesh (Ti/PtPd(10%)O_x). The electrogenerated ClO^- was quantified on the basis of the absorption band at 292 nm (A_λ = 292) of the UV-Vis spectrum. The effect of initial pH, concentration of NaCl, cell potential difference and electrolysis time were investigated in this study. The results showed that the electrolysis of aqueous NaCl solutions increases the solution pH up to high values (≥ 8.0) that favor the formation of ClO^- over chlorine or hypochlorous acid. The hypochlorite concentration increases significantly at pH values > 7.0 and shows a linear trend with increasing NaCl concentration and with increasing cell potential difference. When the cell potential and NaCl concentration are held constant, the maximum hypochlorite value during electrolysis depends on both the cell potential and NaCl concentration. The Ti/PtPd(10%)O_x anode favors the production of hypochlorite ions, making this anode a promising material for use in electrochemical oxidation of wastewater via an indirect mechanism.

• 한국응용과학기술학회지
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• 제37권5호
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• pp.1138-1150
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• 2020

본 연구는 다양한 식물 추출물들이 가지고 있는 항산화 능력과 자외선 차단 능력을 동시에 조사하여 추후, 항산화 효과가 있는 자외선 차단제를 개발하고자 실험을 실시하였다. 먼저 33종의 식물 추출물들의 자외선 차단 능력을 조사하기 위하여 자외선 파장 280~400nm 사이의 흡광도 스펙트럼을 조사하고, 이로부터 우수한 자외선 차단능력을 갖는 것으로 보이는 식물 추출물로 황금, 홉, 녹차, 감초, 방풍, 칡, 그라비올라, 밀싹, 상백피, 가시박, 옻, 등 11종을 선별하였다. 선별된 식물추출물의 총 폴리페놀 함량, 총 플라보노이드 함량, DPPH radical 소거 활성을 측정하여 항산화 활성 정도를 살펴보고, 이로부터 다시 자외선 차단 능력과 항산화 활성이 동시에 우수한 식물 추출물로 황금, 홉, 감초추출물 3종을 선정하였다. 선정된 황금, 홉, 감초추출물을 1:1:1로 혼합하여 겔 형태의 크림을 제조하고, 이 크림이 가지는 자외선 차단 효과를 배양된 세포에 자외선을 조사하였을 때 보여주는 세포 손상 방어 효과를 측정하는 방법으로 결정하였다. 연구 결과, 선정된 식물 추출물의 혼합물은 자외선 흡수 능력에서 상호 보완적이며, 세포 손상 방어 효과도 증가하였음을 확인하였다. 이와 같은 결과를 통하여 다양한 식물 추출물들이 가지고 있는 항산화 능력과 자외선 차단 능력을 동시에 결정할 경우 항산화 효과가 있는 자외선 차단제 개발이 가능함을 확인하였다.

• 한국식품과학회지
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• 제42권6호
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• pp.699-704
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• 2010

유채유에 감광제나 금속이온을 첨가하거나 UV처리를 하였을 때 어떠한 차이가 있는지 알아보기 위하여 MS-전자코를 이용하여 분석하였다. 유채유를 저장하였을 때 저장기간이 증가함에 따라 지방의 품질이 변화되면서 휘발성분이 증감하였는데 판별함수분석(DFA) 결과 DF1값의 영향을 받았으며 품질 변화가 많이 일어날수록 DF1값이 음의 방향으로 이동하였다. 암소에 비하여 UV를 처리하였을 때가 오히려 DF1값의 변화 폭이 크게 나타났다(DF1 $r^2$=0.9481 F=307.07). 실온(17, $26^{\circ}C$)보다는 냉장온도($4^{\circ}C$)에 보관할 때 휘발성분의 변화가 적게 일어났다. 또한 자외선 처리 유무와 온도를 달리 저장할 경우 온도에 의한 영향에 비해 자외선에 의한 영향이 크게 나타났다. ${\gamma}$DF1 값이 암실에서는 각각 $4^{\circ}C$의 경우 0.099, $17^{\circ}C$에서 0.187, $26^{\circ}C$에서 0.278값을 나타냈고 UV 처리 구에서는 각각 $4^{\circ}C$에서 0.554, $17^{\circ}C$는 0.558, $26^{\circ}C$에서는 0.542값을 나타냈다. 감광제인 cytochrome C을 0.1, 0.3, 0.5 mg/%첨가 하였을 때 첨가량이 증가함에 따라 휘발성분의 패턴 변화가 크게 나타났으며 금속이온인 $Cu^{2+}$를 10, 15, 20 mg% 첨가할 경우에도 첨가량이 증가함에 따라 변화가 크게 일어났다. 또한 유채유의 산패 조건에 따른 전자코의 mass spectrum의 감응도 변화는 이미 보고된 GC/MS의 분석 결과와 유사한 pentane, pentanal, 1-pentanol, hexanal, n-octane, 2-hexenal, heptanal, 2-heptenal, decane, 2-octenal, undecane, dodecane과 같은 성분들로 나타났다.