• 한국안전학회지
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• 제30권6호
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• pp.148-155
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• 2015

Using dispersants is known to be an effective solution to accelerate the natural dispersion and being an appropriate oil spill response strategy. By breaking up large oil chunks into small droplets, dispersants are generally intended to help reducing further oil exposures and slicks. Collecting property data of circulating crude oil in South Korea and understanding the interaction between crude oils and dispersions need to be preceded for the effective dispersant use. This paper provides an property analysis of three selected oils which have the same composition of spilt oils from the Herbei Spirit Incident and conducts an emulsification and toxicity experiment with selected domestic and foreign dispersants. Results will present a direction of future domestic dispersants' development which aimed at eco-friendly and safety.

• Fisheries and Aquatic Sciences
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• 제10권2호
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• pp.86-92
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• 2007

Adult Dungeness crabs are restricted primarily in the lower part of Glacier Bay, Alaska, but the interaction of larval dispersion and adult distribution is unknown. To understand the larval occurrence in the upper part of Glacier Bay, Dungeness crab larvae, sea surface temperature (SST), and sea surface salinity (SSS) were collected at 16 near-shore and 12 mid-channel stations in Glacier Bay, southeastern Alaska during six sampling periods from March through August 2000. Each station was visited from one to five times during the entire sampling period. Geographic Information System (GIS) was used to contour SST and SSS distribution in Glacier Bay. Seven to 27 stations were visited during each sampling period. Most larvae (85% were zoeae I) occurred during May 31 to June 14, 2000. Larval density varied from none to $51.4\;100\;m^{-3}$ between stations. A few later stage larvae occurred during later sampling periods. Overall, no relationship between larval densities, and SSS, and SST existed. Larvae occurring in the upper bay were probably transported by tidal currents from the lower bay; adult Dungeness crabs in Glacier Bay have a relatively high density near the mouth of the bay but decrease sharply around 40km north of the mouth. The lack of adult crabs in the upper 60km of the bay may be related to lower salinity, resulting in sharp haloclines, or colder temperatures which are not conducive to survival or growth of either larvae or adults.

• 한국응용과학기술학회지
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• 제26권3호
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• pp.288-296
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• 2009

In this study, the silica-based hybrid material with high barrier property was prepared by incorporating ethylene-vinyl alcohol (EVOH) copolymer, which has been utilized as packaging materials due to its superior gas permeation resistance, during sol-gel process. In preparation of this EVOH/$SiO_2$ hybrid coating materials, the (3-glycidoxy-propyl)-trimethoxysilane (GPTMS) as a silane coupling agent was employed to promote interfacial adhesion between organic and inorganic phases. As confirmed from FT-IR analysis, the physical interaction between two phases was improved due to the increased hydrogen bonding, resulting in homogeneous microstructure with dispersion of nano-sized silica particles. However, depending on the range of content of added silane coupling agent (GPTMS), micro-phase separated microstructure in the hybrid could be observed due to insufficient interfacial attraction or possibility of polymerization reaction of epoxide ring in GPTMS. The oxygen barrier property of the mono-layer coated BOPP (biaxially oriented polypropylene) film was examined for the hybrids containing various GPTMS contents. Consequently, it is revealed that GPTMS should be used in an optimum level of content to produce the high barrier EVOH/$SiO_2$ hybrid material with an improved optical transparency and homogeneous phase morphology.

• Asian-Australasian Journal of Animal Sciences
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• 제5권1호
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• pp.183-188
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• 1992

Behaviour of 7 horned Japanese Black Cattle (3-9 years old) kept in a $450m^2$ dry-lot under loose housing condition was observed in the daytime (0930-1730 h) during 3 consecutive days. Eating and lying behaviour of cattle and the positions of all animals when lying together were recorded at 10-min intervals. Agonistic encounters and social licking interactions in the herd were also recorded. The cattle established a social hierarchy which was near linear. An irregularity in the diurnal rhythm of lying behaviour was found on the 3rd day, which appeared to be caused by oestrus behaviour of a herdmate. Eating frequency showed greater variation among individuals than lying frequency, and the most dominant animal ate most frequently in the herd. The spatial pattern of the herd when lying indicated a relatively loose dispersion in the lot. Higher ranking cattle tended to lie down more frequently near the hay rack in the lot, so that lower ranking animals had more difficult access to feed. Cattle with more social licking interactions had a tendency to lie down near each other irrespective of proximity of social order, therefore it was suggested that social preference among particular individuals occurred in the herd.

• 한국음향학회지
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• 제11권4호
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• pp.22-30
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• 1992

섬유강화 복합재료의 동탄성계수와 감쇠특성을 규명하기 위하여 랜덤하게 분포된 무한 실린더 형상의 산란계를 가진 메질내에서, 축방향으로 분극되어 조화운동을 하는 탄성파의 전파에 관하여 연구하였다. 단일 실린더에 대한 산란계수로부터 Lax의 준결정근사법을 이용하여 다중산란에 관한 이론을 유도하였고, 매질내에서의 파동전파특성을 내포하는 분산관계식을 얻었다. 다중 산란에 의한 실린더간의 상호작용을 수식화하기 위하여 필요한 실린더의 쌍분포함수는 몬테카를로 모의실험을 이용하여 구하였다. 수치적으로 구한 감쇠계수 및 유효전단강성을 주파수와 면적밀도의 함수로 제시하였다.

• Transactions on Electrical and Electronic Materials
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• 제4권1호
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• pp.21-23
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• 2003

The washing effects on pretilt angle generation in a nematic liquid crystal (NLC), 4-n-pentyl-4'-cyanobiphenyl (5CB) on a rubbed polyimide (PI) surface with trifluoromethyl moiety have been successfully studied. The pretilt angle of 5CB is increased by the washing process on the rubbed PI surface. The surface tension on the rubbed PI surface increases with the rubbing strength RS and then saturated above RS: 150 mm. The pretilt angle of 5CB for all washing processes on the rubbed PI surface decreases with the surface tension. We have found that the pretilt angle of 5CB on the rubbed PI surface may be attributed van der walls (VDW) dispersion interaction between the LC molecules and the polymer surfaces having trifluoromethyl moieties.

• 한국표면공학회지
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• 제45권1호
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• pp.1-7
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• 2012

Multi-walled carbon nanotube (MWCNT) aluminum composite powders were deposited to form coatings using a high velocity oxygen fuel (HVOF) spraying process. High thermal energy and contact with atmospheric oxygen were supplied as the MWCNT aluminum composite particles were exposed to a gas flow field at high temperature (${\sim}3.0{\times}10^3$ K) during HVOF spraying. As a result, the particles underwent full or partial melting and rapid solidification due to the high thermal energy, and the exposure to oxygen induced the interfacial reaction of MWCNTs within the particle. The electrical and mechanical properties of MWCNT aluminum composite coatings were evaluated based on microstructure analysis. Electrical resistivity, elastic modulus, and micro-hardness, of the MWCNT aluminum composite coatings were higher than those of pure aluminum coating. The contribution of MWCNTs to the aluminum matrix can be attributed to their high electrical conductivity, dispersion hardening and anchoring effects. The relationship among the properties and the interaction of the MWCNTs with the aluminum matrix is discussed.

• 공업화학
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• 제21권5호
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• pp.500-504
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• 2010

다중벽 탄소 나노튜브(Carbon nanotube, MWNTs)의 우수한 전기적 기계적 특성과 폴리우레탄의 우수한 기계적 물성을 이용하여 우수한 전기 전도성 복합체를 제조하기 위하여 말단기가 polyurethane로 기능화 된 탄소 나노튜브(PU-g-MWNTs)를 제조하였다. 말단기에 형성된 폴리우레탄과 고분자 메트릭스 간의 상용성으로 인한 계면 접합력으로 인해 기능화된 CNT 복합체 기능화 되지 않은 CNT에 비해 우수한 분산성을 나타내었다. PU-g-MWNT/PU 복합체의 전기 전도성을 PU-g-MWNT의 농도에 따라 측정하였으며 percolation threshold 이론에 의해 해석하였다. 그 결과 PU-g-MWNT/PU 복합체의 전기전도성은 임계농도 0.78 wt%과 임계지수 0.945를 가짐을 확인하였다.

• 한국인쇄학회지
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• 제25권2호
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• pp.85-93
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• 2007

The printed mottle is recognized as the most common printing problems in using coated paper and one of the most difficult problems to solve in offset printing. Printed mottle is caused by an uneven penetration of ink into the paper and binder migration. The prevention of printed mottle requires of coating color formation, especially the minimum of binder migration. Printing worked by interaction of printing ink, coated paper and printing pressure. In this study, we investigated the effect of the properties changing of coated paper and printing conditions such as ink dispersion, nip condition and amount of ink transfer.

• Bulletin of the Korean Chemical Society
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• 제28권8호
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• pp.1273-1279
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• 2007

The NiSO4 supported on Fe2O3 catalysts were prepared by the impregnation method. No diffraction line of nickel sulfate was observed up to 30 wt %, indicating good dispersion of nickel sulfate on the surface of Fe2O3. The addition of nickel sulfate to Fe2O3 shifted the phase transition of Fe2O3 (from amorphous to hematite) to higher temperatures because of the interaction between nickel sulfate and Fe2O3. 20-NiSO4/Fe2O3 containing 20 wt % of NiSO4 and calcined at 500 oC exhibited a maximum catalytic activity for ethylene dimerization. The initial product of ethylene dimerization was found to be 1-butene and the initially produced 1-butene was also isomerized to 2-butene during the reaction. The catalytic activities were correlated with the acidity of catalysts measured by the ammonia chemisorption method.