• Food Science and Biotechnology
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• v.18 no.1
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• pp.223-227
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• 2009

The fruits of Cornus kousa Burg. were extracted with 80% aqueous methanol (MeOH) and the concentrated extract was partitioned with ethyl acetate (EtOAc), n-butanol (n-BuOH), and $H_2O$. From the EtOAc traction, 5 triterpenoids were isolated through repeated silica gel ($SiO_2$), octadecyl silica gel (ODS), and Sephadex LH-20 column chromatography (c.c.). These compounds were determined to be ursolic acid (1), corosolic acid (2), taraxasterol (3), betulinic acid (4), and betulinic aldehyde (5) on the basis of their spectroscopic data including electronic ionization mass spectrometry, ultraviolet spectroscopy, infrared spectroscopy, and nuclear magnetic resonance. This is the first reported isolation of these compounds from this plant. Also, compounds 1, 3, 4, and 5 show a relatively high inhibitory activity against human acyl-CoA: cholesterol acyltransferase-1 (hACAT-1) with inhibition values of $52.8{\pm}0.7$, $91.1{\pm}0.4$, $93.0{\pm}0.7$, and $96.2{\pm}0.2%$ at a concentration of $100{\mu}M$, respectively.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.144-144
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• 2016

플라즈마 전해 산화법(Plasma electrolytic oxidation)에 의해 형성된 코팅층은 특유의 기공구조로 인해 부식 환경에 노출 시 부식액의 침투가 급속히 이루어지는 단점이 있다. 이를 극복하기 위한 방법으로 유기코팅, sol-gel법, 폴리머 코팅 등에 의해 기공을 봉공(sealing)하는 방법이 제안되고 있다. 본 연구에서는 Al 합금의 플라즈마 전해 산화 처리 후 질산 세륨 수용액(Cerium nitrate solution)에 의한 봉공 효과를 확인하고자 하였다. PEO 코팅을 위한 전해액은 2g/L의 KOH와 $2g/L\;Na_2SiO_3$를 증류수에 용해시켜 준비하였다. PEO 코팅층은 Al 시편을 전해액 내에 위치시켜 양극으로 하고 STS를 음극으로 하여 $0.1A/cm^2$의 펄스 정전류밀도(주파수: 100Hz, 듀티비: 20%)를 15분 동안 인가하여 형성시켰다. 봉공을 위한 실링액은 증류수에 $0.3g/L\;H_2O_2$와 $1g/L\;H_3BO_3$를 첨가하고, $Ce(NO_3)_3$를 농도 변수로 첨가하여 준비하였으며, PEO 코팅 처리된 시편을 실링액에 침지하여 실링액의 농도와 침지시간을 달리하여 봉공을 실시하였다. 제작된 PEO 코팅층에 대해 SEM, EDS, XRD를 이용한 표면분석을 실시하였으며, 내식성을 확인하고자 동전위분극시험을 실시하였다. 연구 결과, 세륨 실링 처리된 PEO 코팅 층에서 미량의 세륨 성분이 검출되었으나, 세륨계 화합물 생성에 의한 마이크로 크기의 기공의 폐쇄는 관찰되지 않았다. 또한, 전기화학적 특성 평가 결과 실링 처리된 PEO 코팅층의 경우 Al 모재에 비해 2차수 정도 감소된 부식전류밀도를 나타내었다. 이 같은 내식성의 향상은 세륨 성분에 의한 부식 억제 효과 때문으로 판단된다.

• Journal of Surface Science and Engineering
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• v.44 no.2
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• pp.60-67
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• 2011

Ternary B-C-N coatings were deposited on Si(100) wafer substrate from $B_4C$ target by RF magnetron sputtering technique in $Ar+N_2+CH_4$ gas mixture. In this work, the effect of reactant gas ratio, $CH_4/(N_2+CH_4)$ on the composition, kinds and amounts of bonding states comprising B-C-N coatings were investigated using two different bias power sources of continuous and unipolar DCs. In addition, the tribological properties of coatings were studied with the composition and bonding state of coating. It was found that the substrate bias power had an effect on chemical composition, and all of the obtained coatings were nearly amorphous. Main bonding states of coatings were revealed from FTIR analyses to be h-BN, C-C, C-N, and B-C. The amount of C-C bonging mainly increased with increase of the reactant gas ratio. From our studies, both C-C and h-BN bonding states improved the tribological properties but B-C one was found to be harmful on those. The best coating from tribological points of view was found to be $BC_{1.9}N_{2.3}$ composition.

• Bulletin of the Korean Chemical Society
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• v.25 no.11
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• pp.1661-1666
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• 2004

The reaction of titanium tetraisopropoxide with 2 equiv of N,N-diethyl acetoacetamide affords Ti($O^iPr)_2(CH_3COCHCONEt_2)_2$ (1) as colorless crystals in 80% yield. Compound 1 is characterized by spectroscopic (Mass and $^1H/^{13}C$ NMR) and microanalytical data. Molecular structure of 1 has been determined by a single crystal X-ray diffraction study, which reveals that it is a monomeric, cis-diisopropoxide and contains a six coordinate Ti(IV) atom with a cis($CONEt_2$), trans($COCH_3$) configuration (1a) in a distorted octahedral environment. Variable-temperature $^1H$ NMR spectra of 1 indicate that it exists as an equilibrium mixture of cis, trans (1a) and cis, cis (1b) isomers in a 0.57 : 0.43 ratio at -20$^{\circ}C$ in toluene-$d_8$ solution. Thermal properties of 1 as a MOCVD precursor for titanium dioxide films have been evaluated by thermal gravimetric analysis and vapor pressure measurement. Thin films of pure anatase titanium dioxide (after annealing above 500$^{\circ}C$ under oxygen) have been grown on Si(100) with precursor 1 in the substrate temperature range of 350- 500$^{\circ}$ using a bubbler-based MOCVD method.

• Korean Journal of Food Science and Technology
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• v.20 no.4
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• pp.576-584
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• 1988

Neutral detergent fiber(NDF) were extracted from the Nampung, Milyang #23, Whasung and Jinhung varieties of rice by neutral detergent fiber method. To determine the properties of NDF three factors were measured : water-binding capacity(WBC), Fe-binding capacity and sodium taurocholate binding with NDF. The average WBC of NDF was $5.60{\pm}0.87gH_2O/g$ NDF, and the average Fe-binding capacity ranged from 24.63% at pH 5.0 to 19.6% at pH 6.0 and 48.98% at pH 7.0. Binding of sodium taurocholate with NDF was determined in vitro using C-14 labeled sodium taurocholate at 100M sodium taurocholate concentrations. NDF binding of Jinhung was 27.87 while Nampung, Milyang #23 and Whasung measured 32% each. When sodium taurocholate concentrations were raised from $40{\mu}M\;to\;240{\mu}M$ the tendency of binding increased as the concentrations increased, but not linearly.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.5
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• pp.455-462
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• 2000

The objective of this study was to examine the physicochemical characteristics of coagulation reaction between loess and red tide organisms (RTO) and its feasibility, in developing a technology for the removal of RTO bloom in coastal sea. The physicochemical characteristics of loess were examined for a particle size distribution, surface characteristics by scanning electron microscope, zeta potential, and alkalinity and pH variations in sea water. Two kinds of RTO that were used in this study, Cylindrothen closterium and Skeietonema costatum, were sampled in Masan bay and were cultured in laboratory. Coagulation experiments were conducted using various concentrations of loess, RTO, and a jar tester. The supernatant and RTO culture solution were analyzed for pH, alkalinity, RTO cell number. A negative zeta potential of loess increased with increasing pH at $10^(-3)M$ NaCl solution and had -71.3 mV at pH 9.36. Loess had a positive zeta potential of +1,8 mV at pH 1.98, which resulted in a characteristic of material having an amphoteric surface charge. In NaCl and $CaCl_2$, solutions, loess had a decreasing negative zeta potential with increasing $Na^+\;and\;Ca^(+2)$ ion concentration and then didn't result in a charge reversal due to not occurring specific adsorption for $Na^+$ ion while resulted in a charge reversal due to occurring specific adsorption for $Ca^(+2)$ ion. In sea water, loess and RTO showed the similar zeta potential values of -112,1 and -9.2 mV, respectively and sea sand powder showed the highest zeta potential value of -25.7 mV in the clays. EDLs (electrical double-layers) of loess and RTO were extremely compressed due to high concentration of salts included in sea water, As a result, there didn't almost exist EDL repulsive force between loess and RTO approaching each other and then LVDW (London-yan der Waals) attractive force was always larger than EDL repulsive force to easily form a floe. Removal rates of RTO exponentially increased with increasing a loess concentration. The removal rates steeply increased until $800 mg/l$ of loess, and reached $100{\%}$ at 6,400 mg/l of loess. Removal rates of RTO exponentially increased with increasing a G-value. This indicated that mixing (i.e., collision among particles) was very important for a coagulation reaction. Loess showed the highest RTO removal rates in the clays.

• Economic and Environmental Geology
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• v.47 no.4
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• pp.421-430
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• 2014

In this study, a series of autoclave experiments were conducted in order to investigate the geochemical and mineralogical effects of carbon dioxide on deep subsurface environments. High pressure and temperature conditions of $50^{\circ}C$ and 100 bar, which are representative environments for geological $CO_2$ sequestration, were created in stainless-steel autoclaves for simulating the interactions in the $scCO_2$-groundwater-mineral reaction system. Zeolite, a widespread mineral in Pohang Basin where many researches have been focused as a candidate for geological $CO_2$ sequestration, and groundwater sampled from an 800 m depth aquifer were applied in the experiments. Geochemical and mineralogical alterations after 30 days of $scCO_2$-groundwater-zeolite sample reactions were quantitatively examined by XRD, XRF, and ICP-OES investigations. The results suggested that dissolution of zeolite sample was enhanced under the acidic condition induced by dissolution of $scCO_2$. As the cation concentrations released from zeolite sample increase, $H^+$ in groundwater was consumed and pH increases up to 10.35 after 10 days of reaction. While cation concentrations showed increasing trends in groundwater due to dissolution of the zeolite sample, Si concentrations decreased due to precipitation of amorphous silicate, and Ca concentrations decreased due to cation exchange and re-precipitation of calcite. Through the reaction experiments, it was observed that introduction of $CO_2$ could make alterations in dissolution characteristics of minerals, chemical compositions and properties of groundwater, and mineral compositions of aquifer materials. Results also showed that geochemical reactions such as cation exchange or dissolution/precipitation of minerals could play an important role to affect physical and chemical characteristics of geologic formations and groundwater.

• Asian Journal of Turfgrass Science
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• v.22 no.1
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• pp.25-34
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• 2008

This study was conducted to determine the optimum dose ranges for a mutation breeding based on the observations of a seed germination and an early growth in turfgrasses. Three warm season (Zoysiagrass, Bermudagrass, and Seashore paspalum) and four cool season turfgrasses (Kentucky bluegrass, Tall fescue, Perennial ryegrass, and Creeping bentgrass) were used in this study. We investigated the percentage of a seed germination and a seedling growth after irradiating the turfgrass seeds with various doses of gamma-ray (50, 100, 150, 200, 250, 300, 400, and 500 Gy). After 24 h with a gamma irradiation, the seeds were sown on the wet filter paper in a petri dish and maintained for 3 weeks at 30$^{\circ}C$ for the warm season turfgrasses and at 25$^{\circ}C$ for the cool season turfgrasses. Data on a seed germination and a seedling growth with three replications were collected. The percentage of seed germination was decreased with an increase of the gamma-ray dose. Shoot and root growth, and the fresh weight were decreased significantly as the radiation dose was increased. A radiation dose indicating a 50% growth inhibition ($LD_{50}$) with a gamma irradiation was varied among those turfgrass species used, with the highest at about 500 Gy for bermudagrass and the lowest at 100Gy for tall fescue. The optimum dose for a gamma irradiation for a selection of turfgrass mutants was considered to be about 300, 150, 500, 150, 200, 100 and 200 Gy for zoysiagrass, seashore paspalum, bermudagrass, Kentucky bluegrass, perennial ryegrass, tall fescue, and creeping bentgrass, respectively.

• Journal of the Korean Institute of Telematics and Electronics
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• v.18 no.3
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• pp.42-51
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• 1981

Boron was predeposited into p (100) Si wafer at 94$0^{\circ}C$ for 60minutes to make the back surface field. High tempreature diffusion process at 1145$^{\circ}C$ for 3 hours was immediately followed without removing boron glass to obtain high surface concentration Back boron was annealed at 110$0^{\circ}C$ for 40minutes after boron glass was removed. N+ layer was formed by predepositing with POCI3 source at 90$0^{\circ}C$ for 7~15 minutes and annealed at 80$0^{\circ}C$ for 60min1es under dry Of ambient. The triple metal layers were made by evaporating Ti, Pd, Ag in that order onto front and back of diffused wafer to form the front grid and back electrode respectively. Silver was electroplated on front and back to increase the metal thickness form 1~2$\mu$m to 3~4$\mu$m and the metal electrodes are alloyed in N2 /H2 ambient at 55$0^{\circ}C$ and followed by silicon nitride antireflection film deposition process. Under artificial illumination of 100mW/$\textrm{cm}^2$ fabricated N+PP+ cells showed typically the open circuit voltage of 0.59V and short circuit current of 103 mA with fill factor of 0.80 from the whole cell area of 3.36$\textrm{cm}^2$. These numbers can be used to get the actual total area(active area) conversion efficiency of 14.4%(16.2%) which has been improved from the provious N+P cell with 11% total area efficiency by adding P+ back.

• Food Science of Animal Resources
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• v.33 no.6
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• pp.787-795
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• 2013

This study was carried out to investigate the characteristics of goat and cow milk yogurts containing high-exopolysaccharide fermented by Streptoccous thermophilus LFG isolated from kefir. The pH of cow milk yogurt was higher than that of goat milk yogurt. The contents of lactic acid was greater in goat milk yogurt (743.9-1043.8 mg/100 g) than in cow milk yogurt (441.6-709.9 mg/100 g). The numbers of survival lactic acid bacteria were the greatest in goat milk yogurt fermented by Str. thermophilus LFG. Viscosity was greater in cow and goat milk yogurts cultured by Str. thermophilus LFG than in yogurts by Str. thermophilus TH3. Syneresis of yogurt fermented by Str. thermophilus LFG was 9.6-16.1% and 28.2-31.8% in yogurt fermented by Str. thermophilus TH3 after 10 d storage at $4^{\circ}C$. Flavor compounds identified from goat milk were acetone, ethylbutanoate, ethyl-3-methylbutyrate, ethyl-2-butenoate and ethylhexanoate, and those from cow milk were ethylbutanoate, acetone, 2-heptanone and acetoin. Flavor compounds detected from goat milk and cow milk yogurts were acetic acid, butanoic acid, butanol, diethylcarbinol, acetone, diacetyl, decane, 2-methyl-3-pentanone, hexanal, 2-heptanone, acetoin, benzaldehyde, dimethyldisulfide, and dimethyltrisulfide. In sensory evaluation, overall preference and texture values were higher in goat milk yogurt fermented by Str. thermophilus LFG than in cow milk yogurts and the yogurt fermented by mixed culture resulted in the highest score.