• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.83.2-83.2
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• 2010

평판형 고체산화물 연료전지(planar SOFC : Solid oxide Fuelcell)는 높은 전류 효율 및 출력밀도를 가지는 중,대형 발전용 전기소자이다. SOFC 스택을 600~800도에서 작동할 경우, 금속 분리판에서 휘발된 크롬에 의한 열화현상과 금속의 산화에 의한 표면 저항의 증가가 큰 문제점으로 알려져 있으며, 이를 개선하기 위한 많은 연구가 진행되고 있다. 본 연구에서는 금속 분리판의 열화를 억제하기 위한 여러 보호코팅의 특성을 밝히고, 특성차이의 원인을 분석하고자 하였다. 모재는 상용 STS444합금 (Nisshin steel 생산) 2.0mmt 박판을 사용하였으며, 표면 상태를 균일하게 하기 위하여 표면은 동일한 #1200 번 사포로 연마후 코팅하였다. 적용한 코팅은 전기도금 Ni 코팅, (MnCo)3O4 wet powder spray 코팅, (MnCo)3O4 ADM코팅 3종이었으며, 코팅층의 두께는 최적 공정조건에 따라 달리 하였다. 산화후 형성되는 표면 산화물의 전기적 특성을 평가하기 위하여 시험편의 비면적 저항 (ASR : area specific resistance)을 장시간 측정하였다. 측정편의 크기는 가로 4cm ${\times}$ 세로 4cm였으며, 100시간 공기중 산화후 측정하였다. 표면 접촉을 높이기 위하여 Pt paste를 40~50um도포하였으며, 1~0.1A인가된 전류에 대한 저항을 4전극법 (4-probe)으로 측정하였다. 표면 코팅층이 크롬 휘발을 억제하는 정도를 평가하기 위하여 크롬 휘발량을 측정하였다. 시편은 가로 1.5cm ${\times}$ 세로 1cm 였으며, 공급된 공기와 수분의 혼합가스와 응축기 표면에 흡착된 크롬의 양을 ICP-MASS법으로 측정하였다.

• Journal of Animal Science and Technology
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• v.47 no.5
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• pp.759-768
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• 2005

The study was designed to estimate the in vitro rumen by-pass rate of both chromium methionine chelate as an organic supplement and $ClCl_3$ as an inorganic supplement. Rumen by-pass rates of the supplements were evaluted by comparing ruminal metabolites in rumen fluid and Cr and methionine contents in the body of ruminal microorganism. For in vitro digestion examination, basic nutrients for ruminal microbes were supplied with 7g(DM) of feed, 2g of rice straw, and 2g of corn silage per each incubation jar. Three treatments including Control(no supplementation of Cr), T1(1000ppb supplementation of $ClCl_3$) and T2(chromium methionine chelate supplementation equivalent to 1000ppb of Cr content) were prepared with five replications per each treatment. pH of T2 was lower than that of Control and T1 regardless of incubation time. Ammonia content was higher in T2 than in Control and T1 during first 6 hours of incubation. However, the ammonia content in Control was remained low after 6 hours. Total volatile fatty acids(VFA) content in control was increased constantly as incubation time was extended. Therefore, VFA content in T1 and T2 were significantly lower (P<0.05) than those of Control. Dry matter recovery rate by ruminal microorganism was the lowest in T1, however ruminal microbial population was increased most efficiently in T2 during 12 hours of in vitro incubation. Cr concentrations in the body of ruminal microbes were not different(P>0.05) between Control and T2, but it was significantly high in T1(P<0.05). Contents of methionine and cystine in ruminal microbes also were not different between Control and T2(P>0.05), but it was relatively low in T1. Based on the above results, the chromium methionine chelate was believed to by-pass rumen and could remain intact until it reaches small intestine compared to inorganic chromium. This results implies that chromium methionine chelate could be more effective to function in the small intestine of ruminant animals.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.7
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• pp.469-475
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• 2014

The study investigated the physicochemical characteristics and the ecological risk of the Northport sediment in B city and the releasing properties of heavy metals into seawater during the resuspension also studied. The major components of the sediment are fine silt and clay which contains high organic matter and AVS (Acid volatile sulfide) and the ecological risk of the heavy metals in sediment also very high. The release rate of heavy metals into seawater was in order of Pb>>Cu>Cr>>Zn>Cd during the resuspension in a batch experiment, and the heavy metal release mainly attributed to the oxidation of metal sulfides. Heavy metals which came from easily oxidisable metal sulfides rapidly contaminated seawater within about 1.0 h of the sediment resuspension. The sulfide oxidation during the resuspension increased the residual fraction of heavy metals in the sediment, decreased the organic bound fraction, and changed the other fractions of heavy metals in the sediment. The release of heavy metals from the sediment during resuspension was affected by the resuspension time, the oxidation rate of metal sulfides and resuspended concentration of the sediment particle.

• Journal of Environmental Policy
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• v.6 no.3
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• pp.33-56
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• 2007

Use of chemicals has greatly increased along with development of human civilization. Concerns about potential effects of chemicals on human health and environment have also grown accordingly. Due to the enormous number of chemicals being used, however, it is neither practical nor feasible to regulate all the chemicals. Therefore, it is necessary to identify chemicals that deserve more immediate attention, based on the effects on receptors to be protected. This study was initiated by the need for developing management policies for Shihwa-Banwol Techno Valley and its vicinities of korea, where complaints and concerns on environmental contamination have been raised for long time. This study to identifies major chemicals that deserve most immediate attention in environmental health management in this area. For this purpose, the study employed CHEMS-1(Chemical Hazard Evaluation for Management Strategies), and used chemical data from Toxics Release Inventory(TRI) and environmental contamination data from the environmental pollution monitoring network. Top priority pollutants identified in Shihwa-Banwol Techno Valley area were metals and volatile organic compounds, such as dichloromethane, trichloroethylene, diazinon, tetrachloroethylene, chromium compounds, tin compounds, chloroacetic acid, ethyl acetate, and zinc compounds, in an order of decreasing importance. An evaluation of physicochemical properties of the priority chemicals and the environmental pollution monitoring network database in Shihwa-Banwol Techno Valley suggested that the media that are of potential concern would be the atmosphere and aquatic environment.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.2
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• pp.223-230
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• 2008

For the use of extracts from salmon frame as a basic material of Gomtang-like products, various methods (soaking into soybean milk, adding anchovy, and adding spices) for masking fish odor into extracts from salmon frame were examined and the food component characteristics were also compared with commercial Gomtang. According to the results of volatile basic nitrogen, transmission at 660 nm and sensory evaluation of extracts, soaking treatment, which is the soaking of salmon frame into soybean milk, was the most efficient method among the various methods for masking fish odor into extracts from salmon frame. There was no difference in the proximate composition between extracts from salmon frame soaked (FS) and unsoaked (C) into soybean milk. The FS was not detected in heavy metals, such as chromium, lead and cadmium. The taste value of FS (16.26) was higher than that of C and the major amino acids were glutamic acid and aspartic acid. Total amino acid content of FS (3.08 g/100 mL) was also higher than those of C (2.95 g/100 mL) and commercial Gomtang (1.70 g/100 mL), and the major amino acids were glycine, proline, glutamic acid and arginine. The calcium and phosphorus contents of FS/500 mL accounted for 21.7% and 18.5%, respectively, of the recommended daily allowance of mineral for adult.