• Ocean and Polar Research
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• v.31 no.3
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• pp.257-264
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• 2009

Seventeen females of the mud crab Scylla serrata, from the State of Kosrae, Micronesia, were transported to the Fisheries Resources Research Institute, Gyeongsangnam-do, in oxygen-filled plastic bags. After acclimatization to a $30^{\circ}C$ holding temperature, nine females were selected for seed production trials. Spawning was hastened using eyestalk ablations; however, this may not be required in commercialscale mud crab seed production. Primary spawning produced an average of 2.4 million hatched larvae, whereas secondary spawning produced 0.4 million. About 10 days elapsed between spawning and hatching and 30 days between hatching and crablet. Mass mortalities up to 90% were observed between stages zoea 1 and zoea 2 in every trial. The highest survival rate from zoea 1 to crablet was estimated at 0.25%. Most commercial shrimp hatcheries in Korea are equipped with almost all necessary facilities and could be converted easily to mud crab hatcheries, able to run three to four times per year using hatchery technologies developed for blue crabs and Chinese mitten crabs.

• Journal of Animal Science and Technology
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• v.64 no.4
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• pp.671-695
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• 2022

The gastrointestinal tract is a complex ecosystem that contains a large number of microorganisms with different metabolic capacities. Modulation of the gut microbiome can improve the growth and promote health in pigs. Crosstalk between the host, diet, and the gut microbiome can influence the health of the host, potentially through the production of several metabolites with various functions. Short-chain and branched-chain fatty acids, secondary bile acids, polyamines, indoles, and phenolic compounds are metabolites produced by the gut microbiome. The gut microbiome can also produce neurotransmitters (such as γ-aminobutyric acid, catecholamines, and serotonin), their precursors, and vitamins. Several studies in pigs have demonstrated the importance of the gut microbiome and its metabolites in improving growth performance and feed efficiency, alleviating stress, and providing protection from pathogens. The use of probiotics is one of the strategies employed to target the gut microbiome of pigs. Promising results have been published on the use of probiotics in optimizing pig production. This review focuses on the role of gut microbiome-derived metabolites in the performance of pigs and the effects of probiotics on altering the levels of these metabolites.

• Resources Recycling
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• v.21 no.4
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• pp.16-25
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• 2012

There are several kinds of batteries such as zinc-air battery, lithium battery, Manganese dry battery, silver oxide battery, sodium-sulphur battery, lead acid battery, metal hydride secondary battery, nickel-cadmium battery, lithium ion battery, alkaline battery, etc. These days it has been widely studied for the recycling technologies of the used battery from view points of economy and efficiency. In this paper, patents and published papers on the recycling technologies of the used battery were analyzed. The range of search was limited in the open patents of USA (US), European Union (EU), Japan (JP), Korea (KR) and SCI journal articles from 1972 to 2011. Patents and journal articles were collected using key-words searching and filtered by filtering criteria. The trends of the patents and journal articles were analyzed by the years, countries, companies, and technologies.

• Resources Recycling
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• v.27 no.6
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• pp.59-67
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• 2018

Efflorescence is a white deposit of powders in the surface of cement concrete which can also occur in geopolymers. Efflorescence occurs when sodium ions in alkali activator react with atmospheric carbon dioxide to form sodium carbonate components. In this study, we investigated whether the secondary efflorescence can be reduced by controlling the Na/Al mole ratio or by changing the curing temperature and heat curing time in fly ash-based geopolymers. The 28 days compressive strength in geopolymers having Na/Al ratio of 1.0 was higher than geopolymers having Na/Al ratio of 0.8. The strength increased with the increasing curing temperature and longer heat curing time. On the other hand, efflorescence was lower when the curing temperature was high and the heat curing time was longer in the geopolymers having Na/Al ratio of 1.0. The geopolymers having Na/Al ratio of 0.8 showed accelerated efflorescence occurrence than the geopolymers having Na/Al ratio of 1.0. In order to reduce the occurrence of the secondary efflorescence of fly ash-based geopolymers, it will be advantageous to maintain the Na/Al ratio at 1.0, increase the curing temperature, and lengthen the heating curing time.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.362-366
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• 2005

종방향 유속의 연직분포 흐름 특성을 파악하기 위해서 중심각이 $180^{\circ}$인 급변곡선수로에서 실험을 수행하였다. 3차원 유속장 측정은 side-looking ADV를 이용하였다. 실험결과, 흐름이 하류 방향으로 진행함에 따라서 최대 종방향 유속이 하상 근처에서 발생하였으며, 이차류에 의한 이송모멘텀의 분포 값이 바뀌는 단면에서 종방향 유속의 연직분포가 대수분포를 만족하지 않음을 파악하였다 직선하천과는 달리 만곡부 내에서 흐름이 하류방향으로 진행함에 따라서 종방향 유속의 연직분포가 변형되는 현상과 관련된 메카니즘은 지형학적 원인에 의한 원심력 작용은 이차류를 발생시키며, 이로 인해 이송 모멘텀이 종방향 유속의 연직분포를 변형시킨다.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.430-435
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• 2006

사행수로에서 만곡양상에 따라 변화하는 2차류의 연직 및 흐름방향 분포를 이론적으로 예측하기 위해 Odgaard (1986) 및 Chang (1988)의 제안을 바탕으로 새로운 이론식을 유도하였다. 개발된 이론식은 2차류의 횡방향 유속을 주 흐름 및 연직방향의 함수로 표현한다. 이를 검증하기 위해 실험실에 사행도가 각기 다른 두 개의 사행수로를 제작하여 수리실험을 수행하였다. 수리실험결과를 제안된 이론식 및 기존 식과 비교해 보면, 제안된 식은 실측치에 잘 일치하는 반면 기존 식은 과대 산정하는 경향이 있었다. 제안된 이론식을 통해 수리량이 변화는 경우 2차류가 어떻게 변하는지를 확인해 본 결과, 사행도, 조도, 하폭 대 수심비가 클수록 2차류는 증가하였다. 또한 조도 및 하폭 대 수심비의 변화에 따라 2차류의 흐름방향 분포가 민감하게 반응하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1631-1635
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• 2006

본 연구에서는 레이놀즈응력모형(RSM: Reynolds Stress Model)을 이용하여 사다리꼴 개수로 흐름을 수치모의 하였다. 측벽 경사에 따른 사다리꼴 개수로 흐름을 수치모의 하였으며 계산된 평균유속 분포는 기존의 실험 결과와 비교하였다. 그 결과 개발된 레이놀즈응력이 사다리꼴 개수로 흐름을 비교적 잘 예측하는 것으로 나타났다. 또한 사다리꼴 수로에서는 직사각형 개수로 흐름과 달리 velocity dip 현상이 발생하지 않는 것으로 나타났다. 특히 측벽 경사가 32..인 사다리꼴 수로에서의 평균유속 및 바닥 전단응력 분포는 측벽 경사가 큰 경우와 다른 형태의 평균유속 및 전단응력 분포가 형성되는 것으로 나타났다.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.400-404
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• 2009

본 연구에서는 곧은 식생과 유연한 식생 및 다양한 수심비를 갖는 개수로 흐름 조건에 대한 수리실험을 실시하였다. 레이저 도플러 유속계를 이용하여 수로 전체 단면의 유속을 측정함으로써, 이차흐름이 평균유속 및 난류량에 미치는 영향을 분석할 수 있도록 하였다. 평균유속의 경우, 수치모의결과와 동일하게 측벽근처에서 최대 유속이 발생하였다. 유속측정자료를 이용하여 침수식생 개수로 흐름의 벡터도를 살펴본 결과, 침수식생 개수로의 경우 일반 개수로 흐름과는 달리 바닥 와 (bottom vortex)가 측벽 근처에서 매우 활발한 것으로 나타났으며, 이로 인해 수로 중앙의 높은 운동량을 가진 유체가 측벽방향으로 이동하고 있음을 확인하였다. 또한 측벽에서 이차흐름으로 인해 발생하는 강한 하강류가 레이놀즈응력 및 난류 강도의 수직방향 분포 형태에 영향을 미치는 것을 확인하였다.

• Journal of Plant Biotechnology
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• v.3 no.3
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• pp.131-134
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• 2001

In $\lambda$-Zap II vector system, a cDNA library was constructed for the developing secondary xylem mRNA from hybrid poplar, Populus nigra x maximowiczii. A cDNA clone of 1.5 kb in size, pOMTB1.4 encoding a lignin-bispecific O-methyltransferase was screened by plaque hybridization using a probe of 540 bp cDNA amplified by polymerase chain reaction from the cDNA library and identified by nucleotide sequencing. Its nucleotide sequence contains one open reading frame of 366 amino acids. The deduced amino acid sequence in comparison with that of Populus tremuloides showed the differences of 9 amino acids and revealed 85-99% homology among alfalfa, poplar and aspen.

• Journal of Species Research
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• v.5 no.3
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• pp.443-458
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• 2016

Ten new species of genus Sarcotragus (Demospongiae: Dictyoceratida: Irciniidae) are described from Geomundo Island and Jejudo Island, Korea. All new species of the Sarcotragus are distinguished from the other reported species of Sarcotragus by the skeletal structure, especially fasciculate primary fibres. The characters of genus Sarcotragus have cylindrical primary fascicles filled with wads of filaments or flattened fascicles. All of the primary fibres are not cored with foreign debris. Secondary fibres have slightly fasciculate branch or plastic-like web. They are all not cored with foreign debris. All skeletal fibres are very irregular. The surface is covered with loose or tight filamentous membrane.