• 한국대기환경학회지
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• 제8권4호
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• pp.221-228
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• 1992

In order to evaluate the degree of air pollution, soils from 125 and 60points of main streets of Seoul and Daejeon, respectively, were sampled and analyzed for the contents of lead, copper, iron and zinc by nitric acid($HNO_3$) extraction followed by atomic absorption spectrophotometry during June and September, 1990. The Pb contents of Seoul and Daejeon were 350.2$\mu$g/g and 175.9$\mu$g/g, respectively, which were 14.5times and 7.3times respectively higher than the control(24.0). In Seoul, the commercial area gave the highest value followed by resdential and industrial areas in the decreasing order, while the order in Daejeon was Industrial, commercial and residential areas. The Cu contents in Seoul and Daejeon were very similar(236.6 and 234.6, respectively) each other, and about 11times higher than the control(20.9). The concentration was highest in industrial, followed by commercial and the lowest in residential areas in Seoul, while the order in Daejeon was industrial, residential and commercial areas. The Fe contents were 25716.5 in Seoul and 22838.6 in Daejeon, both being similar to the control value(22537.0). The value was highest in industrial and next in commercial areas and the lowest in residential area both in Seoul and Daejeon. The Zn contents in Seoul and Daejeon were 728.2 and 404.0, respectively, wihch were 6.3 and 3.6times higher than the control(113.3). The value was highest in commercial and next in industrial areas and the lowest in residental area in Seoul, while the order was industrial, residential and commercial areas in Daejeon. The heavy metal content was higher in the soil of main streets than that of minor streets in Seoul. The content of lead in Seoul was higher in the streets of Chongro-ku(525.9) and Chung-ku(684.8), the central area of the city which had a heavy traffic, than those in Nowon-ku(320.3) and Kwanak-ku(312.6) which had relatively less traffic crowd. The similar pattern was observed in the content of zinc; it was higher in Chongro-ku(1305.0) and Chung-ku(1335.4) than in Nowon-ku(489.1) and Kwanak-ku(569.8). In Daejeon, the contents of lead and zinc were decreasing as the distance from Daejeon Railroad Station increased : they were respectively 157.8 and 447.7 within 2km from the station, 157.6 and 235.7 with in 2-4km, and 63.5 and 156.2 within 4-6km and 58.7 and 142.2 within 6-8km. In summary, the contents of lead, copper and zinc were generally higher in the central area of the city, areas of heavy traffic and areas of industry and commerce.

• 한국토양비료학회지
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• 제28권3호
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• pp.207-217
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• 1995

토양의 중금속 침출에 사용되고 있는 7종의 단일 침출액간의 침출정도 및 상호관계를 Cd, Zn, Cu 및 Pb별로 구하고 각 중금속의 경시적 변화에 따른 함량 및 형태변화를 조사하기 위하여 아연 광산 주변의 논토양과 아연광산의 영향이 거의 없을 것으로 보이는 농공단지 주변의 논토양에 대하여 단일 침출 및 연속 침출을 수행하였다. 단일 침출액으로는 0.1M HCl, 0.1M $HNO_3$, 1M $NH_4OAc$ (pH 7.0), 0.05M EDTA, 0.001M DTRA (pH 7.3), 0.1M $NH_4Ox$ 및 4M $HNO_3$을 사용하였으며 연속침출은 증류수, 0.5M $KNO_3$, 0.5M NaOH, 0.05M EDTA, 4M $HNO_3$의 순으로 침출을 수행하였다. Cd 및 Zn의 경우 각 침출액간의 상호관계식의 상관관계가 매우 높아 중금속 농도의 상호 추정이 가능하였으나 Cu, Pb는 그렇지 못하였다. 아연 광산 주변 논토양을 대상으로 행한 연속침출 결과, 주 존재 형태는 Cd, Zn, Cu 및 Pb 모두 황화물/잔류태였다. Cd의 경우 치환태, Cu의 경우 유기태, 그리고 Pb의 경우는 탄산염태의 함유율이 상대적으로 높았다. 단 Zn의 경우 황화물/잔류태의 함유율이 79% 이상으로 매우 높았다. 각 중금속의 함량 변화는 12년 동안 모두 뚜렷히 감소 하였으나, 형태별 함유율은 거의 변화지 않았다.

• 자원리싸이클링
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• 제30권1호
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• pp.66-76
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• 2021

전기로 제강분진 중에는 아연(Zn), 납(Pb)등과 같은 유가금속들이, 다양한 화합물(산화물 또는 염화물 등)의 형태로 다량 함유되어 있다. 전기로 제강분진 내에 함유되어 있는 이들 유용금속원소들을, 가장 효율적이며 안정적으로 회수할 수 있는 대표적인 방법으로서는 Rotary Kiln Process가 있다. Rotary Kiln Process는 전기로 제강분진에 환원제(Coke, 무연탄)와 석회석(염기도 제어용)을 첨가하여 성형한 후에 가열함으로서, 아연성분을 조산화아연(Crude Zinc Oxide : 60% Zn)의 형태로 회수하는 방법으로 오래전에 이미 상용화되었으며, 지금도 공정 및 설비의 단점을 개선하기 위한 연구개발을 지속적으로 수행하고 있다. 현재 국내에서도 전기로 제강분진을 재활용하여 조산화아연을 생산하는 다수의 상용화공장들이 가동되고 있다. 조산화아연 중에는, 아연성분 외에도 다양한 기타의 성분원소들(Pb, Cd, Sn, In, Fe, Cl, F 등)이 산화물, 염화물, 알칼리 화합물 등의 형태로 함께 혼재되어 있다. 그러므로 조산화아연을 건식 또는 습식아연제련용 원료로서 그대로 사용하게 되면 조산화아연에 함유된 이들 불순물 성분들이 미치는 악영향으로 인하여, 아연제련과정에서 많은 문제점들이 발생하므로. 따라서 이들 불순물 성분원소들을 가능하면 모두 제거하기 위한 건식 또는 습식정제공정이 추가로 필요하다. 따라서 본 연구에서는 조산화아연의 건식휘발 정제공정에서 발생되어 백필터에 포집된 아연(Zn) 및 납(Pb)을 함유한 2차분진(2nd Dust)으로부터 아연(Zn)과 납(Pb)을 효율적으로 분리하고, 더욱 부가가치를 높이기 위하여 Zn-cementation법으로 이들 성분원소들을 금속탄산염의 형태로 분리회수할 수 있는 공정기술에 대하여 기초적인 연구를 수행하였다.

• Food Science and Biotechnology
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• 제16권3호
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• pp.367-373
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• 2007

Livers of skipjack tuna (Katsuwonus pelamis) and yellowfin tuna (Thunnus albacares) were investigated on the food compositional characteristics and also compared to that of Alaska pollack (Theragra chalcogramma). The proximate compositions of skipjack tuna and yellowfin tuna livers were high in crude protein, carbohydrate, and crude ash, while were low in crude lipid when compared to that of Alaska pollack liver. The results of heavy metal suggested that tuna livers appeared safe as a food resource. The total amino acid contents of skipjack tuna and yellowfin tuna livers were 17.7 and 17.1 g/100 g, respectively, and the major amino acids in both livers were aspartic acid, glutamic acid, alanine, valine, leucine, and lysine. Tuna livers were good sources of iron and zinc, while have low lipid content. The extractive nitrogen contents of skipjack tuna and yellowfin tuna livers were 526.5 and 468.2 mg/100 g, respectively, and their major free amino acids were taurine, glutamic acid, and alanine. From the results of taste value, the major taste active compounds among free amino acids were glutamic acid and aspartic acid.

• 한국수산과학회지
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• 제43권5호
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• pp.391-399
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• 2010

This study was conducted to improve the antioxidative activity of instant noodles containing enzymatic extracts from Ecklonia cava (EEC). EEC has relatively better antioxidative activity than extracts from other indigenous plants in Jeju Island. The EEC (2.5 mg/mL) had 82.5% for the hydroxy radical, 78.4% for the DPPH radical, and 64.9% for the superoxide anion radical scavenging activities, and 65.2% for the cell viability (100 ${\mu}g/mL$). According to the texture of the dough, the DPPH free radical scavenging of uncooked instant noodles, sensory evaluation of cooked instant noodles, and turbidity of the cooking drip, the optimal EEC concentration was 1.8% for the instant noodles. The major amino acids in the instant noodles with EEC were glutamic acid (24.2%), proline (10.2%), valine (10.0%), and isoleucine (12.3%). The zinc and iron in the instant noodles were enhanced by adding 1.5-1.8% EEC. The antioxidant activity of instant noodles with EEC was 75.4% for the hydroxy radical, 74.1% for the DPPH radical, and 51.2 % for the superoxide anion radical scavenging activities.

• 한국수산과학회지
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• 제50권3호
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• pp.263-269
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• 2017

The mineral contents, and free amino acid, and fatty acid composition of rack and bag or suspended cultured oysters Crassostrea gigas were compared. The moisture content did not change much from 82.8% to 86.3% in the different culture methods. The glycogen level was low 4.7% during rack and bag culture but high 7.2% during suspended culture. The sodium level was the highest during suspended culture, while copper and zinc level were highest during rack and bag culture. The taurine level was 1,385-1,375 mg/100 g in oyster cultured using the rack and bag method, but that in the market sample was lowest at 1,015.8 mg/100 g. Hydroxyproline, glutamic acid, proline, glycine, and alanine were detected at high levels in the experimental oysters. The polyunsaturated fatty acid content was similar among samples. The docosahexaenoic acid level was 14% with rack and bag culture and 12% with suspended culture, whereas the eicosapentaenoic acid level was 15% with rack and bag culture and 20% with suspended culture. The atherogenic index (AI), thrombogenicity index (TI), and hypocholesterolemic/ hypercholesterolemic (h/H) ratio were important factors in the nutritional evaluation. The AI and TI values were 0.5-0.2, and the h/H ratio were 2.0 and 2.4 with the rack and bag and suspended culture, respectively.

• 한국수산과학회지
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• 제53권3호
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• pp.382-387
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• 2020

This study compared the nutritional characteristics of seasoned laver Pyropia yezoensis with conger eel Conger myriaster seasoning sauce (SL-CES) with those of commercial seasoned laver (C-SL). SL-CES had higher protein and lower ash contents than those of C-SL. However, the moisture and lipid contents did not differ between them (P>0.05). The total amino acid content of SL-CES was 21.79 g/100 g, similar to that of C-SL (21.49 g/100 g). The major amino acids in SL-CES were aspartic acid, glutamic acid, and alanine. The SL-CES contained 125.7 mg calcium, 461.6 mg phosphorus, 2183.7 mg potassium, 9.5 mg iron, and 2.6 mg zinc per 100 g SL-CES. These amounts were all higher than those in C-SL, except for Zn. The major fatty acids in SL-CES were 16:0, 18:1n-9, and 18:2n-6.

• 한국수산과학회지
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• 제51권5호
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• pp.491-498
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• 2018

The objective of this study was to investigate the composition of canned oyster Crassotrea gigas in white sauce (CO-WS). The proximate composition of CO-WS was 74.1% water, 10.4% crude protein, 4.9% crude lipid, and 3.1% ash. The energy converted based on these percentages was 112.2 kcal/100 g, while the salinity was 1.1 g/100 g. In a taste-intensity test using an electronic tongue, the CO-WS showed higher umami taste intensity than the control (canned oyster in commercial white sauce), whereas the intensities of the other tastes (salty, sour, bitter, and sweet) were lower. Because the odor intensity was low, CO-WS was considered to have a relatively weak odor and showed no difference in hardness compared to the control. Sensory evaluation of CO-WS by a panel yielded higher scores for appearance, taste, and texture, and a lower score for flavor compared to the control. The total amino acid content of CO-WS was 8.91 g/100 g, and its major amino acids were aspartic acid, glutamic acid, and leucine. With respect to mineral content, CO-WS had higher calcium and lower zinc contents than the control. These results suggest that CO-WS has excellent nutritional value.

• 자원환경지질
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• 제23권2호
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• pp.161-181
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• 1990

The lead-zinc-silver-iron deposits from the Janggun mine are of hydrothermal-metasomatic origin, characterized by the marked hydrothermal alteration of the wallrocks, such as hydrothermal manganese enrichment of carbonate rocks, silicification, chloritization, sericitization, montmorillonitization and argillic alteration. The ore deposits have been emplaced within the Janggun Limestone of Cambro-Ordovician age at the immediate contacts with apophyses injected from the Chunyang Granite plutons of Late Jurrasic age. They have been structurally controlled by fractures in the carbonate rocks and the irregular intrusive contacts of granitic rocks, and are closely associated with hypogene manganese carbonate deposits. In the mine nine seperate orebodies are being mined. On the basis of the petrological study, hydrothermal alteration zone of this mine may be divided into the following four zones from wallrock to orebody. (I) Primary calcite and dolomite zone${\rightarrow}$(II) dolomitic limestone zone${\rightarrow}$(III) dolomitic zone${\rightarrow}$(IV) rhodochrosite zone${\rightarrow}$ orebody. There was not recongnized Mn and Fe elements in the primary calcite and dolomite zone. But, in the dolomitic limestone and dolomite zone, calcite and dolomite were subjected to weak hydrothermal manganese enrichment and the grade of the manganese enrichment increase oreward. By means of electron probe microanalysis, it was found that manganoan dolomite occured between primary dolomite grains, cross the cleavage of the primary dolomite and around the dolomite grains. Above these result supports that the Janggun manganese carbonate deposits are of hydrothermal metasomatic origin.

• 한국전기전자재료학회논문지
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• 제28권6호
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• pp.351-359
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• 2015

Next-generation displays should be transparent and flexible as well as having high resolution and frame number. The main factor for active matrix organic light emitting diode and next-generation displays is the development of TFTs (thin-film transistors) with high mobility and large area uniformity. The TFTs used for transparent displays are mainly oxide TFT that has oxide semiconductor as channel layer. Zinc-oxide based substances such as indium-gallium-zinc-oxide has attracted attention in the display industry. In this paper, the mobility improvement of low cost oxide TFT is studied for fast operating next-generation displays by overcoming disadvantages of amorphous silicon TFT that has low mobility and poly silicon TFT that requires expensive equipment for complex process and doping process.