• The Korean Journal of Malacology
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• v.30 no.4
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• pp.343-351
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• 2014

We determined the effects of neuroactive compounds known as synthetic larval settlement inducers on the settlement of the Pacific oyster C. gigas pediveliger on the larval collector. Six types of the inducers, serotonin (5-HT), ${\gamma}$-amino butyric acid (GABA), L-3,4-dihydroxyphenylalanine (L-DOPA), norepinephrine, epinephrine and methyl bromide (MB) were tested. All the chemicals induced larval settlement, MB being the most effective with settlement rate of $42.7{\pm}2.7%$, followed by GABA ($35.4{\pm}2.0%$), 5-HT ($29.1{\pm}2.2%$), L-DOPA ($19.2{\pm}2.1%$), epinephrine ($15.2{\pm}0.9%$), and norepinephrine ($11.0{\pm}1.2%$). The chemicals ${\gamma}$-amino butyric acid and methyl bromide were also better in terms of settled density on the collector with their respective density of $1.97{\pm}1.42$ and $2.37{\pm}1.86ind/cm^2$, reminiscent of being most effective candidates for a larval settlement inducer in the oyster hatchery.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.3
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• pp.290-294
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• 1999

An 18-week growth trial was conducted in flow-through aquarium system to investigate the effects of several additives in formulated diets on the growth and body composition of juvenile abalone (Haliotis discus hannai). Four replicate groups of abalone averaging 150 mg were fed one of four isonitrogenous ($33.8\%$) and isolipidic ($5.8\%$) diets containing $5\%$ squid meal, $0.5\%$ attractant, $1\%$ herb or $0.5\%$ lecithin. In addition, these formulated diets were compared to commercial diet. Survival rate and shell growth of abalone were not significantly affected by the different dietary additives and commercial diet (P>0.1). Body weight gain of abalone fed the diet containing herb was higher than those of abalone fed the diets containing squid meal or lecithin and commercial diet (P<0.1). Moisture, protein, lipid and ash contents of soft body were not influenced by dietary additives and commercial diet (P>0.1). The results suggest that herb as additive in this formulated diet can improve weight gain of abalone.

• The Korean Journal of Malacology
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• v.29 no.2
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• pp.139-146
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• 2013

We determined the effects of neuroactive compounds known as synthetic larval settlement inducers on the settlement of the Pacific oyster C. gigas pediveliger on the larval collector. Six types of the inducers, serotonin (5-HT), ${\gamma}$-amino butyric acid (GABA), L-3,4-dihydroxyphenylalanine (L-DOPA), norepinephrine, epinephrine and methyl bromide (MB) were tested. All the chemicals induced larval settlement, MB being the most effective with settlement rate of $42.7{\pm}2.7%$, followed by GABA ($35.4{\pm}2.0%$), 5-HT ($29.1{\pm}2.2%$), L-DOPA ($19.2{\pm}2.1%$), epinephrine ($15.2{\pm}0.9%$), and norepinephrine ($11.0{\pm}1.2%$). The chemicals ${\gamma}$-amino butyric acid and methyl bromide were also better in terms of settled density on the collector with their respective density of $1.97{\pm}1.42$ and $2.37{\pm}1.86\;ind/cm^2$, reminiscent of being most effective candidates for a larval settlement inducer in the oyster hatchery.

• Korean small business review
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• v.42 no.4
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• pp.123-146
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• 2020

This study, targeting KOSDAQ-listed companies, examined the relationship between variability of accruals and corporate characteristics. First, the analysis results show that executives of companies with high debt ratios are more likely to violate debt contracts, so there is a strong temptation to use discretionary accrual items. Second, for companies with large volatility in operating cash flows, Executives of these companies are strongly inclined to utilize accruals for the purpose of abuse of discretion. Third, the larger the company, the more sensitive it is to political costs, so it is less tempted to use the accruals item than a smaller company. Fourth, the corporate age is thought to be the maturity of the company, Executives of such companies have little room to use accruals to abuse their discretion. Fifth, in the case of profit dummy variables, the companies reporting losses have more temporary accrual items than those reporting profits, so this increases the uncertainty in their accounting information than the latter. Sixth, for those companies that are indicated as inappropriate as a result of audit, the more likely their executives are to use the accrual items, and the lower the quality of their accounting profits is. Lastly, Companies audited by 4 Big domestic accounting firms have less discretionary accrual fluctuations than companies audited by non-big 4 accounting firms. Thus, it was found that the accrual amount allows the discretion of corporate executives differently according to the characteristics of the company.

• Journal of Korean Society of Forest Science
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• v.85 no.2
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• pp.244-250
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• 1996

The objectives of this paper were to study the existence of resistant substance to pine gall midge from needles of Pinus densiflora, P. thunbergii, P. virginiana, and P. thunbergii${\times}$P. virginiana, and also to investigat whether terpenoids, fragrant substance contained in those species seduce or evade imago of pine gall midge to oviposit. Also, terpenoids and phenolic compounds were bioassayed on larva. The results are follows. Adults of pine gall midge oviposited indiscriminately all investigated pine species, while gall formation rate by pine gall midge showed 0% in Pinus virginiana, 9% in P. thunbergii${\times}$P. virginiana, 22% in P. thunbergii. It is suggested that young larvae is necrotized by resistant substance in the needles of P. virginiana. This results might mean that fragrant substance, terpenoids, extracted from pine species is not seducible or evadable substance. Larvae of pine gall midge placed on terpenoid and resin were not necrotized. The necrosis rate of larvae of pine gall midge cultivated in the solution of phenolic compounds extracted from needles of P. virginiana, salicylic acid and chitinase showed 89, 92, and 86% respectively. And necrosis rate was 56 and 59% in phenolic compounds extracted from P. densiflora and gallic acid respectively. So, it is postulated that phenolic compounds contained in needles of P. virginiana, salicylic acid and chitinase are resistant substance to pine gall midge.

• Membrane Journal
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• v.21 no.2
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• pp.163-170
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• 2011

Membrane fouling control in water treatment may be the main obstacle for wider implementation and lower cost. A novel fluorescent spectroscope sensor device for membrane fouling integrity monitoring has been developed and evaluated in this study. PSf membranes for water treatment has been fabricated with three types of organic fluorescent materials, OB, FP, KCB. The fluorescent signal from membrane surface was analyzed throughout the filtration process. It was found that the fluorescent signal due to the membrane fouling decreased and the developed device is reliable for membrane fouling monitoring.

• KSBB Journal
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• v.9 no.3
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• pp.332-338
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• 1994

Solubilization phenomena of a protein in a reversed micellar solution were investigated and a hollow fiber membrane extractor was tested for reversed micellar protein extraction equipment. Alkaline protease was used as a model protein compound and the reversed micellar solution was consisted of AOT and isooctane. It was found that protein solubilization was strongly influenced by ionic strength and pH. The distribution coefficient of the protease between the aqueous solution and the AOT/isooctane solution was also observed to be as high as 4.0 within the scope of this experiment. A hollow fiber membrane extractor was constructed and tested for the protein extraction. The overall mass transfer coefficient at a typical experimental condition of this study was observed to be $6.7{\times}10^{-5}cm/s$. It was also found that the mass transfer resistance on reversed micellar solution was the dominant resistance for the protein transfer.

• Membrane Journal
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• v.15 no.3
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• pp.187-197
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• 2005

A membrane contactor is a device that achieves liquid/liquid or gas/liquid mass transfer without dispersion of one phase within another. This is accomplished by passing the fluids on opposite sides of a microporous membrane. This approach offers a number of important advantages over conventional dispersed phase contactors, including absence of emulsions, no flooding at high flow rates, no unloading at low flow rates, and high interfacial area. This article provides a general review of membrane contactors, including operating principles and applications.

• Applied Biological Chemistry
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• v.39 no.5
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• pp.409-413
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• 1996

To search for bioactive compounds from plant resources, 80% methanol extracts of 46 species of weeds were screened for their activities of antimicrobial, antioxidative, antiblebing, antitumor and herbicidal. Among extracts tested, some showed activities at the concentration of $50\;to\;100\;{\mu}g/ml$. Phryma leptostachya var. asiatica, Aster ageratoides, Centipeda minima, Cirsium pendulum, Lythrum anceps showed antibacterial activity. Penthorum chinense, Lindernia procumbens, Aster ageratoides, Dianthus superbus var. longicalycinus showed antiblebing activity. Phyma leptostachya var. asiatica, Juncus effusus var. decipiens, Lindernia procumbens, Aster ageratoides, Dianthus superbus var. longicalycinus, Viscum album var. coloratum showed antitumor activity. Juncus effusus var. decipiens, Hypericum ascyron, Juncus papillosus, Inula britannicar var. chinensis, Scirpus wichurae, Hypericum laxum showed antioxidant activity.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.203-203
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• 2012

국제핵융합실험로(ITER)는 2020년경에 제작 설치가 완료될 예정이다. 이 장치에 한국도 시험블랑켓 모듈(Test Blanket Module: TBM)을 장착할 예정이다. 한국은 ITER 참여국 중 유일하게 지름 1 mm의 흑연 페블에 SiC를 코팅한 중성자 반사 재료를 채택한 것이 특징이다. 중성자 반사재료를 이용하게 되면 독성이 강한 중성자 증배재인 Be의 양을 줄일 수 있다. SiC 코팅은 여러 가지 방법이 알려져 있지만, 지름 1 mm 내외의 흑연 페블에 SiC를 골고루 코팅하기 위해서는 여러 가지 기술이 가미되어야 한다. 본 연구에서는 CVD 및 CVR법을 이용해 SiC를 코팅했으며, CVD의 경우 전구체 물질로 $CH_3SiCl_3$가 사용되었으며, 캐리어 가스로는 $H_2$를 사용했다. 그리고 CVR에서는 평균입도 10 ${\mu}m$의 $SiO_2$를 사용했으며, $1,750^{\circ}C$에서 2시간 노출시켰다. 이렇게 얻어진 SiC 코팅은 XRD, EDS, FE-SEM 등을 활용한 여러 가지 분석으로 확인할 수 있었다.