• Korean Journal of Food Science and Technology
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• v.26 no.2
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• pp.152-156
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• 1994

The purplish red pigment from the roots of Lithospermum erythrorhizon, a Korean edible wild plant, has been investigated concerning it's value as a natural colorant for Korean traditional foods. An attempt was made to isolate pigments and define their characteristics. Two compounds of isobutylshikonin and acetylshikonin were identified by melting point determination and spectra of UV, IR, and $^{1}H-NMR$. To examine the utility of these naphthoquinone pigments for foods, the effect of various pH values on stability were determined over a period of storage. Buffered solutions of acetylshikonin and isobutylshikonin at pH 3 and 5 showed stable purplish red. The absorption maxima if acetylshikonin and isobutylshikonin over the range of pH 3 to 7 were 518 nm and 520 nm, respectively. A bathochromic shift to 588 nm at pH 10 was observed on these two naphthoquinone pigments. Sensory evaluation was performed with acetylshikonin and isobutylshikonin of identical absorbance. These two pigments revealed purplish red color in Munsell system.

• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.273-279
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• 1999

Forty plants used as tea materials were chosen for determining the contents of total phenolics, selenium (Se), ${\beta}-carotene$, ${\alpha}-tocopherol$ and ascorbate. Total phenolics and ascorbate contents were analyzed colorimetrically. The Se contents were measured by hydride-atomic absorption spectrometry. The contents of ${\beta}-carotene$ and ${\alpha}-tocopherol$ were simultaneously determined by high performance liquid chromatography using separate detectors, UV for ${\beta}-carotene$ and FL for ${\alpha}-tocopherol$ analyses. The contents of these antioxidants were as follows (per 100 g dry plant); Contents of total phenolics in green tea leaf, black tea leaf, oolong tea leaf and instant coffee were about 7 g and the Se contents in corni fructus and arrowroot were found to be about $4{\mu}g$, which were the highest among all plants used. Contents of ${\beta}-carotene$ in eucommiae cortex, persimmon leaf and green tea leaf were 8587, 6222 and $3652\;{\mu}g$ respectively. The persimon leaf contained the highest ${\alpha}-tocopherol$ content (33 mg) and then followed by eucommiae cortex (26 mg), green tea leaf (16 mg) and black tea leaf (13 mg) in order. Ascorbate contents were found to be high in green tea leaf (199 mg) and black tea leaf (117 mg).

• Journal of the Korean Geotechnical Society
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• v.20 no.3
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• pp.23-31
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• 2004

Normally, coating is used for protecting reinforced concrete. For this purpose, both organic and inorganic coatings are used. The advantages of inorganic coatings are lower absorption of UV, non-burning etc. On the other hand, organic coatings have the advantage of low permeability of $CO_2, SO_2$ and water. Organic coatings provide better protection for reinforced concrete. However, organic coatings such as epoxy, urethane and acryl reduce long-term adhesive strength by the difference of their thermal expansion coefficients and elastic modules from those of concrete, and the formed coating cover of these is blistered by poor breathing. Also, when organic coatings are applied to the wet surface of concrete, they have a problem with adhesion. In this study, a new coating material for protecting concrete was hybridized with polymer and ceramics. And tests were carried out on its physical and durable characteristics, and safety characteristic on elution. All results were compared with organic coating materials and epoxies and showed that the performance of the developed coating material was not inferior to that of other organic coatings in protecting concrete. On the other hand, safety characteristic on elution was superior to epoxies which were used in this study. So, the developed coating material was considered as a suitable protecting coating material which have advantages of inorganic and organic coatings for protecting underground concrete structures, especially in contact with water.

• Korean Journal of Materials Research
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• v.23 no.3
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• pp.155-160
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• 2013

ZnO thin films co-doped with Mg and Ga (MxGyZzO, x + y + z = 1, x = 0.05, y = 0.02 and z = 0.93) were prepared on glass substrates by RF magnetron sputtering with different sputtering powers ranging from 100W to 200W at a substrate temperature of $350^{\circ}C$. The effects of the sputtering power on the structural, morphological, electrical, and optical properties of MGZO thin films were investigated. The X-ray diffraction patterns showed that all the MGZO thin films were grown as a hexagonal wurtzite phase with the preferred orientation on the c-axis without secondary phases such as MgO, $Ga_2O_3$, or $ZnGa_2O_4$. The intensity of the diffraction peak from the (0002) plane of the MGZO thin films was enhanced as the sputtering power increased. The (0002) peak positions of the MGZO thin films was shifted toward, a high diffraction angle as the sputtering power increased. Cross-sectional field emission scanning electron microscopy images of the MGZO thin films showed that all of these films had a columnar structure and their thickness increased with an increase in the sputtering power. MGZO thin film deposited at the sputtering power of 200W showed the best electrical characteristics in terms of the carrier concentration ($4.71{\times}10^{20}cm^{-3}$), charge carrier mobility ($10.2cm^2V^{-1}s^{-1}$) and a minimum resistivity ($1.3{\times}10^{-3}{\Omega}cm$). A UV-visible spectroscopy assessment showed that the MGZO thin films had high transmittance of more than 80 % in the visible region and that the absorption edges of MGZO thin films were very sharp and shifted toward the higher wavelength side, from 270 nm to 340 nm, with an increase in the sputtering power. The band-gap energy of MGZO thin films was widened from 3.74 eV to 3.92 eV with the change in the sputtering power.

• Food Science and Preservation
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• v.12 no.1
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• pp.48-53
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• 2005

Comparative effects between commercial fumigation (methyl bromide/MeBr, phosphine $gas/PH_3$) and gamma irradiation (5, 10 kGy) on dried red pepper were investigated in terms of it microbiological quality, moisture content Hunter's colors, and UV-visible spectra during storage for 8 months at mom temperature. The non-treated control samples showed total aerobic bacteria as $4.8\times10^5\;CFU/g$ in powdered state and $1.8\times10^2\;CFU/g$ in whole red repper. While yeasts and molds were $1.7\times10^5\;CFU/g$ in powdered pepper and $5.0\times10^2\;CFU/g$ in whole pepper, respectively. The effect of chemical fumigant on microbial decontamination was negligible, whereas irradiation at 5 kGy was proven to reduce the microbial populations by 2 to 3 log cycles that could improve the hygienic quality of powdered pepper. Moisture content of the samples showed no noticeable changes resulting 1mm irradiation or fumigation. Immediately after treatments, irradiation or fumigation reduced Hunter's lightness (L), redness (a), and yellowness (b) of the samples (p<0.05), but there was no difference in color parameters between the control and all treated stoups after 4 months of storage. It was found that storage period was more influential than irradiation or fumigation to changes in moisture and color of dried red pepper and ie powder.

• Bulletin of the Korean Chemical Society
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• v.28 no.4
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• pp.581-588
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• 2007

To enhance the photodecomposition of concentrated ammonia into N2, Pt/V-TiO2 photocatalysts were prepared using solvothermal and impregnation methods. Nanometer-sized particles of 0.1, 0.5 and 1.0 mol% V-TiO2 were prepared solvothermally, and then impregnated with 1.0 wt% Pt. The X-ray diffraction (XRD) peaks assigned to V2O5 at 30.20 (010) and Pt metal at 39.80 (111) and 46.20 (200) were seen in the 1.0 wt% Pt/ 10.0 mol% V-TiO2. The particle size increased in the order: pure TiO2, V-TiO2 and Pt/V-TiO2 after thermal treatment at 500 °C, while their surface areas were in the reverse order. On X-ray photoelectron spectroscopy (XPS), the bands assigned to the Ti2p3/2 and Ti2p1/2 of Ti4+-O were seen in all the photocatalysts, and the binding energies increased in the order: TiO2 < Pt/V-TiO2 < V-TiO2. The XPS bands assigned to the V2p3/2 (517.85, 519.35, and 520.55 eV) and V2p1/2 (524.90 eV) in the V3+, V4+ and V5+ oxides appeared over V-TiO2, respectively, while the band shifted to a lower binding energy with Pt impregnation. The Pt components of Pt/ V-TiO2 were identified at 71.60, 73.80, 75.00 and 76.90 eV, which were assigned to metallic Pt 4f7/2, PtO 4f7/2, PtO2 4f7/2, and PtO 4f5/2, respectively. The UV-visible absorption band shifted closer towards the visible region of the spectrum in V-TiO2 than in pure TiO2 and; surprisingly, the Pt/V-TiO2 absorbed at all wavelengths from 200 to 800 nm. The addition of vanadium generated a new acid site in the framework of TiO2, and the medium acidic site increased with Pt impregnation. The NH3 decomposition increased with the amount of vanadium compared to pure TiO2, and was enhanced with Pt impregnation. NH3 decomposition of 100% was attained over 1.0 wt% Pt/1.0 mol% V-TiO2 after 80 min under illumination with 365 nm light, although about 10% of the ammonia was converted into undesirable NO2 and NO. Various intermediates, such as NO2, -NH2, -NH and NO, were also identified in the Fourier transform infrared (FT-IR) spectra. From the gas chromatography (GC), FT-IR and GC/mass spectroscopy (GC/MS) analyses, partially oxidized NO and NO2 were found to predominate over V-TiO2 and pure TiO2, respectively, while both molecules were reduced over Pt/V-TiO2.

• Journal of the Korean Chemical Society
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• v.61 no.1
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• pp.29-33
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• 2017

Formation of Au particles in nonstoichiometric $Cu_{2-x}{^I}Cu{_2}^{II}O_{3-{\delta}}$ ($x{\approx}0.20$; ${\delta}{\approx}0.10$) oxide from aniline + hydrochloric acid mixtures and chloroauric acid in the ratios 30 : 1; 60 : 1; 90 : 1 (S1-S3) by volume and 0.01 mol of copper acetate, $Cu(OCOCH_3)_2.H_2O$, in each case is performed by sol-gel growth. Powder x-ray diffraction (XRD) results show Au particles are dispersed in tetragonal nonstoichiometric dicopper (I) dicopper (II) oxides, $Cu_{2-x}{^I}Cu{_2}^{II}O_{3-{\delta}}$ ($x{\approx}0.20$; ${\delta}{\approx}0.10$). Average crystallite sizes of Au particles determined using Scherrer equation are found to be in the approximate ranges ${\sim}85-140{\AA}$, ${\sim}85-150{\AA}$ and ${\sim}80-150{\AA}$ in S1-S3, respectively which indicate the formation of Au nano-micro size particles in $Cu_{2-x}{^I}Cu{_2}^{II}O_{3-{\delta}}$ ($x{\approx}0.20$; ${\delta}{\approx}0.10$) oxides. Hysteresis behaviour at 300 K having low loop areas and magnetic susceptibility values ${\sim}5.835{\times}10^{-6}-9.889{\times}10^{-6}emu/gG$ in S1-S3 show weakly ferromagnetic nature of the samples. Broad and isotropic electron paramagnetic resonance (EPR) lineshapes of S1-S4 at 300, 77 and 8 K having $g_{iso}$-values ${\sim}2.053{\pm}0.008-2.304{\pm}0.008$ show rapid spin-lattice relaxation process in magnetic $Cu^{2+}$ ($3d^9$) sites as well as delocalized electrons in Au ($6s^1$) nano-micro size particles in the $Cu_{2-x}{^I}Cu{_2}^{II}O_{3-{\delta}}$ ($x{\approx}0.20$; ${\delta}{\approx}0.10$) oxides. Broad and weak UV-Vis diffuse reflectance optical absorption band ~725 nm is assigned to $^2B_{1g}{\rightarrow}^2A_{1g}$ transitions, and the weak band ~470 nm is due to $^2B_{1g}{\rightarrow}^2E_g$ transitions from the ground state $^2B_{1g}$(${\mid}d_{x^2-y^2}$>) of $Cu^{2+}$ ($3d^9$) ions in octahedral coordination having tetragonal distortion.

• Korean Journal of Materials Research
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• v.9 no.10
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• pp.1006-1011
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• 1999

B-doped hydrogenated amorphous silicon carbide (a-SiC:H) thin films were prepared by plasma-enhanced chemical-vapor deposition in a gas mixture of $SiH_4$, $CH_4$ and $B_2H_6$. Microstructures and chemical properties of a-SiC:H films grown with varing the volume ratio of $CH_4$ to $SiH_4$ were characterized with various analysis methods including scanning electron microscopy(SEM), X-ray diffractometry(XRD), Raman spectroscopy, Fourier-transform infrared (FTIR) spectroscopy. X-ray photoelectron spectroscopy(XPS), UV absorption spectroscopy and photoconductivity measurements. While Si:H films grown without $CH_4$ showed amorphous state, the addition of $CH_4$ during deposition enhanced the development of a microcrystalline phase. By introducing C atoms into the film, Si-Si and Si--$\textrm{H}_{n}$ bonds of a -Si:H films were gradually replaced by Si-C, C-C, and Si--$\textrm{C}_{n}\textrm{H}_{m}$ bonds. Consequently, the electrical resistivity and optical bandgap of a-SiC:H films were increased with the C concentration in the film.

• Korean Journal of Food Science and Technology
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• v.30 no.3
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• pp.697-701
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• 1998

Two major flavonoid compounds having inhibition activity of xanthine oxidase from onion skin were separated, isolated and identified by ODS chromatography, Sephadex LH-20 chromatography, UV/visible absorption spectroscopy and FAB Mass. Spectral analyses indicated that $F_1$ was a flavonol having 3,5,7,3'-OH and 4'-glucoside (quercetin 4'-glucoside), and $F_2$ was a flavonol having 3(5),7,3',4'-OH (quercetin). FAB-Mass of fraction $F_1\;and\;F_2$ in positive-ion-mode produced a spectra containing main ions at m/z 465, corresponding to the $(M＋H)^+$ ion of quercetin 4'-glucoside, and m/z 303, corresponding to the $(M＋H)^+$ ion of quercetin. The inhibition mechanisms of $F_1\;and\;F_2$ were a mixture of the uncompetative and non-competative modes, with respect to xanthine as a substrate.

• Journal of the Korean Society of Food Science and Nutrition
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• v.20 no.4
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• pp.369-375
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• 1991

Carotenoid pigments from muscle of mussel, Mytilus coruscus, and blue mussel edulis, were separated by thin layer and column chromatography. The isolated carotenoids were identified by comparative test with reference carotenoids, reduction with sodium borohydride, isomerization with iodine and absorption spectrophotometry. The carotenoid content in the muscle of mussel were 0.4mg% in male and 2.7mg% in female, and the carotenoids were composed of 23.4%, 33.4% mytiloxanthin, 26.3%, 22.5% 3, 4, 3'-trihydroxy-7', $8'-didehydro-{\beta}-carotene$, 24.8%, 22.8% pectenoxanthin, 14.0%, 9.9% pectenolone and 5.1%, 6.1% diatoxanthin in male and female, respectively. While, the carotenoid contents in the muscle of blue mussel were 1.1mg% in male and 3.2mg% in female, and the carotenoids were composed of 33.8%, 35.6% mytiloxanthin, 28.4%, 44.7% pectenoxanthin, 18.1%, 5.0% diatoxanthin, 9.7%, 8.7% pectenolone and 5.5%, 3.1%, 3, 4, 3'-trihydroxy-7', $8'-didehydro-{\beta}-carotene$ in male and female, respectively.