• 공업화학
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• 제33권1호
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• pp.109-112
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• 2022

Lime has been used for the neutralization of acidic waste because it is cheap and available in large quantities. The resulting sludge often contains a considerable amount of unreacted lime due to alkali overdosing, even during automatic neutralization processes, which mainly arises from the poor solubility of lime. The sludge cake from lime neutralization of Ilkwang Mine also contained high percentages of calcium and magnesium. The elemental content of the sludge cake was compared with those obtained from a simulation of the lime neutralization facility installed at Ilkwang Mine. A Goldsim^® model estimated the degree of lime overdosing to be 19.1% based on the fractions of ferrous oxide. The analysis suggests that resolubilization of aluminum hydroxide could occur in the settling basin, in which pH exceeded 10 due to the continued dissolution of the overdosed lime. The present study demonstrated that chemical analysis of sludge combined with process simulation could provide a reasonable estimate of mass balance and chemistry in a neutralization facility for acid mine drainage.

• Applied Biological Chemistry
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• 제41권4호
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• pp.222-227
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• 1998

The activities of enzymes of carbohydrate metabolism have been determinated in the host cytosolic and bacteroid fractions of cowpea (Vigna unguiculata) nodules formed with B. japonicum I 16 and in roots of nodulated cowpeas. The host cytosolic fraction of the nodules contained the enzymes of glycolytic pathway and the pentose phosphate pathway, whereas the bacteroids had only limited capacity for carbohydrate metabolism and appeared to be insufficient for the complete glycolytic pathway as well as starch synthesis and degradation. In a time-course study, using plants grown in a glasshouse, the acetylene-reducing activity (ARA) of the nodules increased in parallel with the total N content of plants and protein of the nodules until approximately 8 weeks after planting. Subsequently, the weight and size of the nodules and the weight of the plants continued to increase, but there was a sharp decrease in the ARA and the total N content of the plants.

• 에너지공학
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• 제27권2호
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• pp.81-88
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• 2018

Every day a huge amount of paper is being used, most of them are thrown after using. This directly impacts on the environment. Therefore, waste paper management is necessity to protect the environment from its annihilation and pollution. Paper recycling products consist of printing paper, newspaper, corrugated containers, magazine paper and so on. Reuse waste paper will reduce the consumption of wood and virgin pulp as recycling one ton of newsprint can save approximately 1 ton of wood, meanwhile recycling 1 ton of printing paper can save more than 2 tons of wood. With increasing recycling rates, lower quality paper fractions may be included. Thus the selection of a paper recycling technology is a crucial first design consideration. The paper recycling must be accompanied by appropriate technology to manage a huge volume of wastepaper. The specific objectives of this study were as follows: (1) comprehensive literature reviews of paper production and consumption, (2) figure out about paper recovery and utilization, (3) investigate the paper recycling in the sustainable times, (4) introduce eco-friendly recycling technology to paper industry.

• Journal of the Korean Wood Science and Technology
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• 제43권2호
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• pp.274-285
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• 2015

In view of the environmental and health hazards posed by synthetic insecticides, the use of plant products as botanical insecticides has gained increasing in recent years. In this study, we reported the insecticidal activity of extracts isolated from Coptis chinensis. On crude extraction, among the various solvent types tested (water, 1% (w/v) of sodium hydroxide, 70% ethanol), the 70% ethanol extract showed the best insecticidal activity (36.5%). Three different fractions (n-hexane, chloroform and ethyl acetate) were obtained from crude extract (70% ethanol) of the chloroform fraction and found to have noteworthy insecticidal activity (62.9%) by filter paper contact bioassay. Their chemical structures were identified as 2-methoxy-4-vinylphenol and aniline by head space-GC-MS analysis. Both compounds displayed a dose-dependent insecticidal activity of Myzus persicae (Sulzer). Insecticidal activity at the lowest concentration tested (500 ppm) approached 85.4% in the aniline compared with 79.9% in the 2-methoxy-4-vinylphenol. The insecticidal activity was greater for the aniline than 2-methoxy-4-vinylphenol. It is believed that the insecticidal activity is due mainly to the presence of aniline.

• Applied Biological Chemistry
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• 제41권4호
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• pp.246-250
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• 1998

The cytotoxic activity of methanol extracts of 25 leguminous seeds in vitro was evaluated by sulforhodamine B assay, using the five human solid A549 lung, SK-OV-2 ovarian, SK-MEL-2 melanoma, XF-498 CNS and HCT-15 colon tumor cell lines. The responses varied with both cell line arid leguminous seed used. Extracts of Canavalia lineata and Glycine soja revealed potent cytotoxic activity against A549 arid SK-MEL-2 cell lines. Moderate activity was observed in the extracts of Cassia obtusifolia and Glyeine max var. chungtae, and C. lineata and Vigna angulasis against SK-MEL-2 and HCT-15 cell lines, respectively. The other seed extracts were ineffective against model tumor cell lines. Because of their potent cytotoxic activities, the activity of each solvent fraction from C. lineata and G. soja was determined and the potent activity was produced from their chloroform fractions. As a naturally occurring therapeutic agent, leguminous seeds described could be useful for developing new types of anti-tumor agents.

• Journal of Microbiology and Biotechnology
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• 제19권7호
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• pp.681-684
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• 2009

This study was carried out to evaluate the inhibitory effect of Flammulina velutipes extracts on tyrosinase activity and to identify its biologically active component. The ethyl acetate and n-butanol extracts showed potent tyrosinase inhibitory activities. Subsequently, fractions of the n-butanol extract showed only a partial tyrosinase inhibitory activity. The most active compound of tyrosinase inhibitory activity was identified from the ethyl acetate extract as 1',3'-dilinolenoyl-2'-linoleoylglycerol (LnLLn) by comparing its mass, $^1H-$, and $^{13}C-NMR$spectral data with those previously reported in the literature. LnLLn showed tyrosinase inhibitory activity with an $IC_{50}$value of 16.1 ${\mu}g/ml$. These results suggest that the ethyl acetate extract of F. velutipes could be applicable for the development of a new whitening agent.

• 한국재료학회지
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• 제17권8호
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• pp.425-432
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• 2007

The microstructural evolution of ferritic 9Cr-1Mo-V-Nb steel, subjected to creep-fatigue at $550^{\circ}C$, was evaluated nondestructively by measuring the ultrasonic velocity. The variation of the ultrasonic velocity with the fatigue life fraction exhibited three regions. In the first region ($N/N_f$<0.2), a significant increase in the velocity was observed, followed by a slight increase between the fatigue life fractions of $0.2N_f$ and $0.8N_f$, and then a decrease in the final region. The change of the ultrasonic velocity during creep-fatigue was interpreted in relation to the microstructural properties. This study proposes an ultrasonic nondestructive evaluation method of quantifying the level of damage and microstructural change during the creep-fatigue of ferritic 9Cr-1Mo-V-Nb steel.

• Fisheries and Aquatic Sciences
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• 제21권11호
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• pp.35.1-35.7
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• 2018

Background: The aim of this study was to investigate the in vitro inhibitory effects of Fucofuroeckol-A isolated from Eisenia bicyclis against tyrosinase activity and 3-isobutyl-1-methylxanthine (IBMX)-induced melanin biosynthesis in B16F10 melanoma cells. Result: Among the ethanolic (EtOH) extract of E. bicyclis and its organic solvent fractions, the ethyl acetate (EtOAc) soluble fraction showed a noticeable inhibitory effect on mushroom tyrosinase with an $IC_{50}$ value of $37.6{\pm}0.1{\mu}g/mL$. Repeated column chromatography of the active EtOAc fraction resulted in the isolation of Fucofuroeckol-A. It evidenced more potent tyrosinase inhibitory effect with an $IC_{50}$ value of $11.4{\pm}1.4{\mu}M$ than arbutin ($IC_{50}=1076.6{\pm}44.3{\mu}M$), which was used as a positive control. Lineweaver-Burk plots suggest that Fucofuroeckol-A plays as a noncompetitive inhibitor against tyrosinase. Furthermore, we have evaluated the inhibitory effects of Fucofuroeckol-A on IBMX-induced melanin formation in B16F10 melanoma cells. Fucofuroeckol-A ($12.5-100{\mu}M$) exhibited a significant inhibition of melanin production in the melanoma cells. Conclusion: In the present study, we suggested that Fucofuroeckol-A might prove possibility as a novel inhibitor of melanin biosynthesis in cosmetic applications.

• 한국토양비료학회지
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• 제31권4호
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• pp.392-399
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• 1998

본 연구에서는 합성 요소억제제나 질산화억제제와는 달리 쑥(Artemisia asiatica)과 같은 천연물에 의한 토양중 요소분해와 질산화작용에 대한 저해효과를 검토하고저 하였다. 이를 위 위하여 쑥의 열수추출액과 유기용매 분획추출물을 준비하여 밭토양에 처리하였고 2일, 5일 동안 배양후에 요소태질소와 암모늄태질소, 질산태 질소를 측정하고 요소분해균과 urease 효소활성에 대한 각 추출액과 분획추출물의 영향도 검토하였다. 이번 실험을 통하여 얻은 결과를 요약하면 다음과 같다. 쑥잎의 열수추출액은 요소분해를 미약한 수준으로 촉진하였으나 반면 질산화작용은 억제하였고, 쑥잎 열수추출액을 0.5ml, 3.0 ml를 가하였을 때 질산태 질소함량은 무처리구에 비하여 각각 65.2%, 68.8% 줄어들었다. 쑥잎의 유기용매 분획추출물 중, chloroform분획을 제외한 모든 분획물이 요소분해에 대해 저해효과를 나타내었고 chloroform/methanol 분획을 2.0 ml 가했을 때, 잔존한 요소태질소 함량은 무처리구의 5.8배로 요소분해억제효과가 가장 좋았다. 한편 유기용매 분획추출물들의 질산화작용 억제효과 유무는 불명확 하였다. urease activity의 경우, 요소분해율이 무처리구와 비교시 97.5%에서 99.50%로 높게 나타났기 때문에 분획물이 urease의 활성을 저해하지 않는 것으로 생각되었다. 요소분해 bacteria 수는, 쑥의 chloroform 분획을 처리한 경우를 제외하고 모든 처리에 의해 감소하였다 (적요 2의 결과와 일치). 이로서 요소분해 저해효과는 urease의 활성을 저해하기 보다는 요소분해균을 저해하기 때문에 나타나는 것으로 생각되었다. 각 추출물 성분에 대한 예비시험과 박층 chromatogram을 통해, 그 조성이 복잡하고 다양한 화합물들이 요소분해와 질산화작용 억제과정에 관여할 것으로 추측되며 이를 분획 또는 단일활성 물질을 추적하여 그 효과를 확인할 일이다.

• 열처리공학회지
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• 제14권4호
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• pp.205-211
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• 2001

The characteristics of super duplex stainless steel were investigated on its fibrous structure and dispersed structure. These structures consist of various volume fractions and distributions of the austenite phase that were obtained by changing the heat treatment temperature and cycle. The fibrous structure had higher austenite volume fraction than dispersed structure on the same temperature. As the austenite volume fraction increased in both structures, tensile strength and elongation increased, but hardness decreased. Fatigue life of fibrous structure parallel to rolling direction was shorter than that of perpendicular to rolling direction. Fatigue life of dispersed structure was longer than parallel fibrous structure, and shorter than perpendicular fibrous structure. Fatigue crack propagation rate of fibrous structure was faster than that of dispersed structure.