• Economic and Environmental Geology
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• v.40 no.6
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• pp.771-784
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• 2007

This study shows the weathering characteristics of mica-schist affected by faulting and metamorphism through laboratory tests. Frozen-thaw test, which simulate the physical-chemical weathering processes in the laboratory, shows the important influence of foliation developed in mica-schist, resulting in $20{\sim}40%$ reduction of UCS according to weathering grade of rock. Slaking durability test was carried out for different weathering grade rock specimens and indicated that the specimens from fault area had a low durability index compared to other relatively fresh samples. XRD analysis allowed to estimate the dynamic evolution of mineral composition through wet-dry cycle in which the chlorite was the most important mineral leached out during slaking test. The creep test indicated that the main deformation produced along the foliation plane. The compacted clay minerals between discontinuity planes influence on the discontinuity shearing properties and result in a big difference between peak shear strength and residual strength. The results of laboratory tests on mica-schist show the possibility of a important deformation along the foliation plane or discontinuity.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.6
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• pp.682-688
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• 2013

In this study, we investigated about cell toxicity and oxidative stress of HepG2 cell by treatment of sodium fluoride (NaF) and fluoride extracts from krill Euphausia superba meat, shell, whole body and krill meal. The cell toxicity showed significant at 300 and $500{\mu}g/mL$ NaF treatment group. But krill (Euphausia superba) fluoride extract (KFE) treatment in all groups were not toxic. The superoxide radical production increased significantly in NaF treated group, but there was no significant change in KFE treated group. The superoxide dismutase activity was a significant increase 21.5% at $100{\mu}g/mL$ and 24.7% at $300{\mu}g/mL$ treatment group of fluoride extracts from krill meat, and 8.7% at $300{\mu}g/mL$ in krill meals, compared to the control group. However, hydroxy radical flux and catalase and glutathione peroxidase activity of fluoride extracts from krill meat did not change. As a result, for a short period of time, NaF treatment in HepG2 cells affect the cell toxicity and oxidative stress, but in the case of KFE, these were not recognized. Thus, depending on the type of food ingested with fluoride, cell toxicity and oxidative stress was found to be different.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.4
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• pp.343-350
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• 2013

Instant krill gruel was produced using peeled Antarctic krill Euphausia superba as a high nutritional ingredient and the food quality was investigated. The food quality of krill gruel was examined by measuring proximate composition, cholesterol, calorie, Hunter color value, total amino acids, fatty acids, fluoride, viscoelastic properties, and by sensory evaluation. The krill gruel had a moisture content of 87% and a pH of 6.65. The krill gruel contained 51 kcal/100 g, and 0.1% fat and 3.5 mg/100 g cholesterol. Its fatty acid composition exhibited high levels of unsaturated fatty acids. The levels of oleic acid and linolenic acid were high, and n-3, n-6, and n-9 fatty acid contents ranged from 1% to 6%. The total amino acid content was 2132 mg/100 g, and the levels of glutamic acid, aspartic acid, leucine, alanine, and arginine were particularly high. Essential amino acids accounted for over 30% of the total amino acids. Fluoride level in the krill gruel was 3.07 mg/kg. The viscoelastic properties of the krill gruel were determined as 6.28 Pa at shear stress of 2.51 Pa. In the recovery test, the elastic restoring force after deformation was low.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.1262-1265
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• 2004

송전용량 증가를 위해 개발되어 최근 본격적으로 사용되고 있는 STACIR/AW 송전선은 송전용량의 증가에 따라 그 운전환경도 변화하여 연속사용온도의 경우, 기존 ACSR 전선의 90t에 비해 높은 $210^{\circ}C$로 규정 되어 있을 만큼 고온에서 운전되고 있다. 따라서 STACIR/AW 송전선은 이도설계와 그 운용에 있어서 운전 온도 상승에 따른 각별한 주의관리가 필요하다 실제 STACIR/AW송전선은 그 설계단계에서도 이와 같은 고온운전 환경을 고려하여 고온에서도 소정강도를 유지하는 내열 Al도체와 이도제어를 위한 낮은 열팽창 특성의 INVAR합금(Fe-35Ni계 합금)을 강선으로 하는 특화된 재료로 구성되어 있다. 그러나 이와 같은 재료 설계적 보완책에도 불구하고 실제 송전선은 전선의 자중, 철탑 간에 형성된 가설장력과 같은 다양한 응력이 고온환경에서 부하되는 복합 열화 상태에 노출되어 있고, 이것은 재료학적인 관점에서 크릴 변형 발생의 가능성을 높이고 있으나 이것에 대한 연구 또는 실험결과는 크게 미미한 실정이다. 본 연구에서는 STACIR/AW $410mm^2$ 송전선과 그 구성소재를 대상으로 $200^{\circ}C$, $300^{\circ}C$에서 장시간 열화한 후, 구성소재의 탄성계수, 열팽창계수 및 STACIR/AW전선의 크림변형 거동을 조사하여 열화에 노출된 STACIR/AW 송전선의 이도변화 거동을 규명하고자 하였다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.5
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• pp.520-527
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• 2013

This study developed patties using the Antarctic krill Euphausia superba and investigated the food quality of the patties. Three different types of krill patty were produced: krill patties with added 1) corn oil (CKP), 2) AA grade surimi (AKP), and FA grade surimi (FKP). Their proximate composition, Hunter color value, texture, sensory evaluation, and levels of astaxanthin, cholesterol, calories, total amino acids, fatty acids, and fluoride were investigated. The moisture and crude protein contents were highest in FKP. The calorie and astaxanthin contents were highest in CKP and lowest in AKP. The cholesterol content was highest in CKP and lowest in AKP. Measuring the Hunter color value of cross-sections of the patties, the L values were highest for FKP, and the a and b values highest for AKP. The total amino acids were highest in FKP and lowest in CKP. The major fatty acids were highest in FKP. The hardness and chewiness were highest in FKP and lowest in CKP. The fluoride content was highest in AKP and lowest in FKP. The sensory evaluation had the highest scores for FKP and lowest for CKP. Accordingly, FKP appears to have better food quality than the other two products.

• Journal of the East Asian Society of Dietary Life
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• v.19 no.5
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• pp.776-782
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• 2009

This study was conducted to develop functional soybean paste with krill (Euphausiacea) as compared to a conventional soybean paste (S1). Soybean containing 10%, 20% and 30% (w/w) krill (S2~S4, respectively) was prepared and quality characteristics (moisture, crude fat, crude protein, ash, reducing sugar, pH, titratable acidity, total acidity and buffering power) were assessed during fermentation for 150 days. As well, antioxidative activities of krill soybean paste were compared to those of control soybean paste based on total phenolic compound content and free radical scavenging activity, including the 1,1-diphenyl-2-picryl-hydrazil (DPPH) scavenging activity and the thiobarbituric acid value (TBA value). The moisture content of all samples decreased to 41.91~53.47% during fermentation, while the crude fat increased to 1.98~5.21% with increasing addition of krill. Additionally, crude protein increased slightly to 8.24~14.08% with increasing addition of krill after 120 days of fermentation. Ash content was 15.96~18.92%. The reducing sugar content of S2, S3 and S4 was higher than those of S1 with increasing length of fermentation. S2, S3, and S4 displayed progressive decreases in pH and progressive increases in titratable acidity compared to S1. The total acidity of all samples was increased, while the buffering power was decreased with increasing fermentation. Especially, the buffering power of S1 was lower than that of S2, S3 and S4. DPPH radical scavenging activity of lipophilic extracts from S2, S3 and S4 was slightly higher than those of S1. However, the radical scavenging activity of hydrophilic extracts from all samples had similar tendencies, regardless of the krill content or fermentation period. Total phenolics increased with increasing fermentation time and TBA value increased with increasing fermentation time and krill content.

• Journal of Environmental Science International
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• v.23 no.1
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• pp.47-52
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• 2014

Antarctic krill (Euphausia superba) is typical of a enormous biomass of marine zooplankton that could provide good nutrition in human body. This study was conducted to identify the nutrition of krill, a live in Antarctic Ocean. The analysis result of fatty acids of krill meal was as follow. The compositions of fatty acid were saturated fatty (SFA) acid 41.41%, monounsaturated fatty acid (MUFA) 21.69%, polyunsaturated fatty acid (PUFA) 36.89%, and p/s ratio was 0.89. The major fatty acids in all parts were eicosapentaenoic acid (EPA, 21.54%), palmitic acid (27.51%), oleic acid (13.35%) and docosahexaenoic acid (DHA, 12.42%). Especially, EPA and DHA were occupied 33.96% of polyunsaturated fatty acid. The mineral contents of krill meal were calcium 24477.21 mg $kg^{-1}$, sodium 14728.69 mg $kg^{-1}$, magnesium 6973.49 mg $kg^{-1}$, potassium 3981.67 mg $kg^{-1}$, iron 395.33 mg $kg^{-1}$ and manganese 5.74 mg $kg^{-1}$. The contents of major vitamin were retinol 86717.37 ${\mu}g$ RE, ${\beta}$-carotene 44.87 ${\mu}g$ RE, tocopherol 2.60 mg, pantothenic acid 1.61 mg, indicating that krill meal contains large amount of retinol and ${\beta}$-carotene.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.5
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• pp.557-561
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• 2010

This feeding experiment was conducted to investigate the effects of dietary inclusion of some additives on growth performance, hematological parameter and fatty acid composition of growing flounder. Triplicate groups of fish (average weight 120 g) were fed one of five diets containing 5% kelp meal (Ke), 10% krill meal (Kr), 1% garlic powder (Ga), 1% citrus meal (Ci) or control diet (Con) without supplementation for 15 weeks. After the feeding experiment, survival was not significantly different among the groups fed the different diets. Weight gain of fish fed the Ci diet was significantly higher than that of fish fed the Kr diet, but not significantly different from Con, Ke and Ga treatments. Feed efficiency and protein efficiency ratio of fish fed the Ga diet were significantly higher than those of fish fed the other diets. Total protein, glucose, GOT, GPT and total cholesterol contents in the plasma were not affected by the dietary additives. Composition of C20:4n-6 in the dorsal muscle of fish fed the Con diet was significantly higher than that of fish fed the other diets. The results of this study suggest that the dietary inclusion of garlic meal at 1% may improve feed utilization of growing flounder.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.4
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• pp.435-443
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• 2018

The Antarctic krill Euphausia superba is important commercially and ecologically as a basic component of the Antarctic Ocean ecosystem. To manage this resource, it is important to determine the distribution and standing of krill in the water layer. Acoustic methods can capture information about the entire water layer quickly. Acoustic surveys were conducted from March 3 to March 14, 2017, using the commercial fishing boat Sejong (7,765 tons). Acoustic systems with a frequency of 38 kHz and a 200 kHz commercial echo sounder (ES70, Simrad, Norway) were used and the acquired data were processed using post processing software. The density and standing of Antarctic krill were determined using the two-frequency difference method, using the characteristics of two frequencies. To compare the frequency difference of krill, the method using the frequency difference according to the krill length, recommended by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) and the values extracted according to the krill length at survey stations where only krill were collected during the study period, were compared. The frequency difference ranges were 3.96-5.91 dB and -3.0~13.8 dB, respectively.

• Journal of Biomedical Engineering Research
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• v.22 no.6
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• pp.551-557
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• 2001

Occlusion of the dural-sac in the lumbar spine was quantitatively analysed using a one motion segment finite element mode developed in this study. Occlusion was quantified by calculating the cross sectional area chance of the dural-sac. In static analysis. less than 2 kN of compressive load could Produced no dural-sac occlusion. whereas 6kN load reduced cross sectional area by 4%, and produced 7.4%, 10.5% occlusion for additional 8 Nm. 10 Nm extension moments. respectively. In creep analysis, 10 Nm extension reduced cross sectional area and volume of the dural-sac by 6.9% and 2.4%, respectively. However. flexion moment could not produce any occlusion. The results suggested that occlusions may result mainly from slackening of ligamentum flavum and disc budging.