• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.7
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• pp.1003-1007
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• 2013

In this study, the antibacterial activities of selected barleys (UB, unhulled barley; PB, pearl barley; and NB, naked barley) and wheat (WG, wheat with germ and endosperm) extracts were evaluated against the food-borne pathogens Staphylococcus aureus KCTC 1927, Escherichia coli KCTC 2593, Salmonella Typhimurium KCTC 2054, and Bacillus cereus KCTC 1014. The amount of the antibacterial biomarker, 2,6-dimethoxy-1,4-benzoquinone (DMBQ), present in selected barleys and wheat, was measured by HPLC. Furthermore, antioxidant activity of samples was determined using the oxygen radical absorbance capacity (ORAC) assay. WG ($22.35{\pm}0.04mm$) was found to be highly inhibitory to Staphylococcus aureus followed by UB ($17.91{\pm}0.10mm$), PB ($16.87{\pm}0.05mm$), and NB ($15.69{\pm}0.20mm$). The antibacterial activity of the selected grains was correlated with antioxidant activities and the amount of DMBQ (Pearson's correlation coefficient, 0.7831). The antioxidant activity of the selected grains was also correlated with the total phenolic content (Pearson's correlation coefficient, 0.9934). WG extract showed significantly higher antibacterial activity, compared with barley extracts such as UB, PB, and NB. The results of this study suggest that barley has a potential in the development of natural antimicrobials and food preservatives for controlling food-borne pathogens.

• Journal of the Korean earth science society
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• v.27 no.2
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• pp.198-208
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• 2006

To investigate the provenance of outer-shelf mud patch in the East China Sea, the geochemical compositions were analyzed and compared with those of Chinese rivers sediments. The mud sedimentary facies are distributed in the central region and sandy mud facies are also widely distributed around the study area. The major elements (Fe, Mg, K, Ti, and Mn) show strong positive correlation with Al, and trace elements also indicate the same characteristics; hence, clay minerals are likely to be the promising host for those elements. The high concentration of Fe, Ti, and Mn elements are found in the western middle part near the Changjiang estuary, indicating that it seems to result from the influence of the Changjiang River. Elemental ratios including Sc/Al, Ti/Nb, Th/Sc, Cr/Th, Nb/Co, and Th/U were thus used as provenance indicators to identify the sediment origins of the East China Sea. The discrimination diagrams clearly show that most of the sediment in the northern part are originated from the Huanghe River, while the muddy sediments in the western part near the Changjiang estuary might come from the Changjiang River, suggesting that the outer-shelf muddy sediments of East China Sea are originated from diverse sources.

• Journal of the Korean earth science society
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• v.29 no.4
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• pp.328-340
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• 2008

To discriminate the provenance of shelf sediments in the western part off Jeju Island, the textual and elemental compositions were analyzed and compared with the sediments originating from Changjiang and Huanghe Rivers of China and the Korean (Keum) River. The sediments in the study area are composed of coarse silt with a mean pain size of $3.6{\sim}8.5{\phi}$ and their $CaCO_3$ contents ranged from 0.92 to 9.75 wt.%. The ratios of TOC over total nitrogen (TN) showed that the study area sediments contained more organic matters of marine origin than those of terrigenous origin. The high concentration of Fe/Al, Ti/Al and Mn/Al figures were found in the southwestern part near the Changjiang esturay, indicating that it seemed to result from the influence of the Changjiang River. The discrimination diagrams including Sc/Al vs Cr/Th, Th/Sc vs Nb/Co and Ti/Nb vs Th/Sc were thus used as provenance indicators to identify the sediment origins of the western part off Jeju Island. Based on these discriminated diagrams it clearly showed that most of the sediment in the western part were originated from the Huanghe River, but the sediments in the southwestern part near the Changjiang esturay might come from the Changjiang River. In contrast, the sediment samples of the northeastern part showed the higher figures than those of the river sediments and other regions, suggesting that the sediments in the western part off Jeju Island must be originated from diverse sources.

• Polymer(Korea)
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• v.28 no.3
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• pp.245-252
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• 2004

We synthesized the vinyl addition-type polynorbomene copolymers using two monomers [5-hexyl-2-norbornene (HNB) and 5-methyleste-2-norbornene(MES-NB)] by means of a cationic ${\eta}^3$-allyl palladium catalyst system{[(${\eta}^3$-allyl)palladium(tricyclohexylphosphine) trifluoroacetate] and [lithium tetrakis(pentafluorophenyl) borate ${\cdot}$2.5 etherate]}. The molecular weights and yields of copolynorbomenes polymerized in various conditions were measured to investigate an optimum polymerization conditions to obtain highly ester-functionalized polynorbomenes. As a Pd catalyst content increased, the molecular weights (Mw) of polymers decreased while polymer yields increased. Also, as a Li cocatalyst content increased, the Mw’s and yields of polymers increased at the same time. The Mw’s of copolymers were also controlled by chain transfer agents such as 1-hexone, 1-octene and 1-decene, and we found that longer 1-decene and 1-octene were more efficient to reduce the Mw’s of polynorbornenes than 1-hexene. On the other hand, the content of chain transfer agents did not give influence significantly on polymer yields. From the $^1$H-NMR and GPC analysis of HNB/MES-NB(feed ratio of 40/60 mol%) copolymer, we found that this copolymer had an about 25 mol% of ester portion and a high molecular weight of 270,000.

• Journal of Animal Science and Technology
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• v.45 no.6
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• pp.957-966
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• 2003

Effects of Salmonella typhimurium lipopolysacharide(LPS) and dietary krill meal on the Growth and feed utilization were investigated in broiler chicks. Eight cages of five newly hatched chicks each were assigned and fed to one of the experimental diets containing 0.0,(basal) 0.5 or 1.0% krill meal during 3 weeks of experimental period. And half(four) of the eight cages were i.p. injected with saline or LPS(Immune response activation) every alternate day three times beginning 8 day-old during 2 week of age. Dietary krill meal did not affect growth, feed efficiency, nitrogen balance(NB), uric acid excretion, and ME utilization when the saline was injected. However, the immune response activation lowered daily gain and feed intake and NB and increased uric acid excretion, and the relative liver and spleen weight. Also, birds fed diet containing krill meal 1.0% reduced the feed efficiency and increased spleen weight, and ME and NB or ME required for gain compared with those fed basal and krill meal 0.5% diets in LPS-injected chicks. During recovery period from the immunological stress in 3rd week of age, the krill meal diet reduced the weight of liver and spleen, The results showcd that dietary krill meal did not affect the growth of broiler chicks, but the higher uric acid excretion or dietary ME value indicated the increased protein decomposition or absorption of dietary energy sources in immune response activated birds.

• Korean Journal of Mineralogy and Petrology
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• v.33 no.2
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• pp.115-127
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• 2020

The Unsang gold deposit has been one of the three largest deposits (Daeyudong and Kwangyang) in Korea. The deposit consists of Au-bearing quartz veins filling fractures along fault zones in Precambrian metasedimentary rock and Jurassic Porphyritic granite, which suggests that it might be an orogenic-type. Based on its mineral assemblages and quartz textures, quartz veins are classified into 1)galena-quartz, 2)pyrrhotite-quartz, 3)pyrite-quartz, 4)pegmatic quartz, 5)muscovite-quartz, and 6)simple quartz vein types. The pyrite-quartz vein type we studied shows the following alteration features: sericitization, chloritization, and silicification. The quartz vein contains minerals including white quartz, white mica, chlorite, pyrite, rutile, calcite, monazite, zircon, and apatite. Rutile with euhedral or medium aggregate occur at mafic part from laminated quartz vein. Two types of rutile are distinguishable in BSE image, light rutile is texturally later than dark rutile. Chemical composition of rutile has 89.69~98.71 wt.% (TiO₂), 0.25~7.04 wt.% (WO₃), 0.30~2.56 wt.% (FeO), 0.00~1.71 wt.% (Nb₂O₅), 0.17~0.35 wt.% (HfO₂), 0.00~0.30 wt.% (V₂O₃), 0.00~0.35 wt.% (Cr₂O₃) and 0.04~0.25 wt.% (Al₂O₃), and light rutile are higher WO₃, Nb₂O₅ and FeO compared to the dark rutile. It indicates that dark rutile and light rutile were formed at different stage. The substitution mechanisms of dark rutile and light rutile are suggested as followed : dark rutile [(V³⁺, Cr³⁺) + (Nb⁵⁺, Sb⁵⁺) ↔ 2Ti⁴⁺, 4Cr³⁺ (or 2W⁶⁺) ↔ 3Ti⁴⁺ (W⁶⁺ ↔ 2Cr³⁺), V⁴⁺ ↔ Ti⁴⁺], light rutile [2Fe³⁺ + W⁶⁺ ↔ 3Ti⁴⁺, 3Fe²⁺ + W⁶⁺ ↔ Ti⁴⁺ + (V³⁺, Al³⁺, Cr³⁺) +Nb⁵⁺], respectively. While the dark rutile was formed by cations including V³⁺, V⁴⁺, Cr³⁺, Nb⁵⁺, Sb⁵⁺ and W⁶⁺ by regional metamorphism of hostrock, the postdating light rutile was formed by redistribution of cations from predating dark rutile and addition of Fe²⁺ and W⁶⁺ from Au-bearing hydrothermal fluid during ductile shear.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.42.1-42.1
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• 2009

오스테나이트 스테인리스강은 우수한 내식성 및 기계적 특성으로 인해 구조용 재료로 널리 사용되고 있다. 표준원전 경수로의 경우 가압기 밀림관소재로 Nb 안정화 오스테나이트 스테인리스강인 type 347 스테인리스강이 사용되고 있다. 그러나 원전배관에서는 운전중 배관내 온도편차에 의한 열응역과 하중변화에 의한 기계적하중에 의해 피로손상을 받는다. 일반적으로 범용 오스테나이트 스테인리스강(AISI 304, 316)의 피로균열 성장거동에 대한 연구결과는 국내외적으로 다수 축적되어 있으나 type 347 탄소, 질소 함량에 따른 기계적 특성 및 피로균열성장 연구는 매우 미비하다. 따라서 본 연구에서는 탄소와 질소의 함량에 따른 기계적거동을 평가하고, 이에 따른 피로균열전파속도를 관찰하여 스테인리스강의 정확한 피로균열전파속도 곡선을 제시하고자 한다. 실험에 사용된 시편은 두께 5mm, 폭 25.4mm CT시편을 사용하였으며, 1mm의 예비균열을 주었다. 그리고 실험온도는 상온과 원전가동온도인 $316^{\circ}C$에서 실시하였으며, 주파수는 10Hz를 주었다. 실험결과 각 함량에 따른 type 347의 미세조직 관찰결과 기지내에 압연방향을 따라 조대한 석출물의 흐름이 관찰되었으며, 크기나 분포가 큰 차이를 보였다. C+N 함량이 낮은 시편은 주로 $0.1\;{\mu}m$ 이하의 미세한 입자들이 오스테나이트 기지조직의 입내와 입계에 고르게 분포되어 있었다. 그러나 C+N 함량이 높은 시편의 경우에는 $0.1\;{\mu}m$ 이하의 미세한 입자들과 함께 국부적으로 $1\sim10\;{\mu}m$의 조대한 입자들이 분포하고 있는 것이 관찰되었다. 그리고 질소의 함량이 높아짐에 따라 인장강도는 증가하였으며, 피로시험결과 고온에서 실험한 피로균열성장률 곡선이 상온보다 높게 나타남을 확인할 수 있었다. 그리고 질소가 적게 첨가되고 탄소의 함량이 많을수록 피로균열성장률은 ASME 곡선보다 낮게 나타났다.

• Korean Journal of Mineralogy and Petrology
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• v.36 no.3
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• pp.185-197
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• 2023

The Gubong Au-Ag deposit consists of eight lens-shaped quartz veins. These veins have filled fractures along fault zones within Precambrian metasedimentary rock. This has been one of the largest deposits in Korea, and is geologically a mix of orogenic-type and intrusion-related types. Korea Mining Promotion Corporation drilled into a quartz vein (referred to as the No. 6 vein) with a width of 0.9 m and a grade of 27.9 g/t Au at a depth of -728 ML by drilling (No. 90-12) in the southern site of the deposit, To further investigate the potential redevelopment of the No. 6 vein, another drilling (No. 04-1) was carried out in 2004. In 2004, samples (wallrock, wallrock alteration and quartz vein) were collected from the No. 04-1 drilling core site to study the occurrence and chemical composition of Ti-bearing minerals (ilmenite, rutile). Rutile from mineralized zone at a depth of -275 ML occur minerals including K-feldspar, biotite, quartz, calcite, chlorite, pyrite in wallrock alteration zone. Ilmenite and rutile from ore vein (No. 6 vein) at a depth of -779 ML occur minerals including white mica, chlorite, apatite, zircon, quartz, calcite, pyrrhotite, pyrite in wallrock alteration zone and quartz vein. Based on mineral assemblage, rutile was formed by hydrothermal alteration (chloritization) of Ti-rich biotite in the wallrock. Chemical composition of ilmenite has maximum values of 0.09 wt.% (HfO₂), 0.39 wt.% (V₂O₃) and 0.54 wt.% (BaO). Comparing the chemical composition of rutile at a depth -275 ML and -779 ML, Rutile at a depth of -779 ML is higher contents (WO₃, FeO and BaO) than rutile at a depth of -275 ML. The substitutions of rutile at a depth of -275 ML and -779 ML are as followed : rutile at a depth of -275 ML Ba²⁺ + Al³⁺ + Hf⁴⁺ + (Nb⁵⁺, Ta⁵⁺) ↔ 3Ti⁴⁺ + Fe²⁺, 2V⁴⁺ + (W⁵⁺, Ta⁵⁺, Nb⁵⁺) ↔ 2Ti⁴⁺ + Al³⁺ + (Fe²⁺, Ba²⁺), Al³⁺ + V⁴⁺+ (Nb⁵⁺, Ta⁵⁺) ↔ 2Ti⁴⁺ + 2Fe²⁺, rutile at a depth of -779 ML 2 (Fe²⁺, Ba²⁺) + Al³⁺ + (W⁵⁺, Nb⁵⁺, Ta⁵⁺) ↔ 2Ti⁴⁺ + (V⁴⁺, Hf⁴⁺), Fe²⁺ + Al³⁺ + Hf ⁴⁺ + (W⁵⁺, Nb⁵⁺, Ta⁵⁺) ↔ 2Ti⁴⁺ + V⁴⁺ + Ba²⁺, respectively. Based on these data and chemical composition of rutiles from orogenic-type deposits, rutiles from Gubong deposit was formed in a relatively oxidizing environment than the rutile from orogenictype deposits (Unsan deposit, Kori Kollo deposit, Big Bell deposit, Meguma gold-bearing quartz vein).

• Journal of the Korean Ceramic Society
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• v.34 no.2
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• pp.123-130
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• 1997

In this study, (Sr.Pb.Ca)TiO3-Bi2O3.3TiO2(SPCT) systems were investigated to develop a new material which has a high dielectric constant, a low dielectric loss and a small TCC(Temperature Coefficient of Capa-citance), and are suitable for high voltage applications as a function of the additions of Bi2O3.3TiO2 from 5 mol.% to 9 mol.%. The result obtained from our investigation showed that up to 6 mol.% Bi2O3.3TiO ad-dition the dielectric constant increased and it deteriorated at higher concentrations with increasing amount of the acicular grains. As a result of some dopants (SiO2, Nb2O3, MnO2) addition to SPCT, the specimens with MnO2 showed good dielectric properties. The dielectric constant decreased, but the TCC was improved with the addition of MnO2 from 0.15 wt.% to 0.45 wt. %.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.210-211
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• 2005

[ $(K_{0.5}Na_{0.5})NbO_3$ ](KNN) 세라믹스의 소결 특성과 압전 특성을 높이기 위해 B-site에 Sb를 치환하여 Sb함량에 따른 특성을 측정 하였다. Sb 의 함량을 0mol $\sim$ 0.1mol 까지 첨가한 결과 소결 밀도는 Sb의 첨가량이 많아질수록 증가하다 Sb-0.08mol에서 4.40g/$cm^3$으로 가장 높은 밀도를 가졌으며, 여기서의 전기기계 결합 계수가(Kp) 0.45로 높은 값을 나타내었다. 상전 이 온도는 375$^{\circ}C$로 순수한 KNN 의 420$^{\circ}C$ 보다 약 45$^{\circ}C$정도 떨어졌으나 orthorhombic에 서 tetragonal 로 바뀌는 전이 온도는 KNN이 220$^{\circ}C$, KNNS 가 225$^{\circ}C$로 크게 변하지 않았다.