• 농업과학연구
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• 제28권1호
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• pp.48-58
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• 2001

This study was conducted to investigate the effects of environmental sound rice farming method on the productivity of rice industry which may result in impacts on the staple food securities. Recently fanners have been concerned about adopting new rice cultivation method such as organic and low input farming system in which fertilizer and pesticide can be substantially reduced so as to alleviate the burden of agro-ecosystem. However, It has been argued about whether or not there are negative impacts on the self sufficiency rate of food, income of farm household and technological adaptability. Therefore this study examined the productivity trend of environmental rice farming system and predicted the long term rice self-sufficiency rate when environmental rice farming system are adopted by assuming various scenarios. It was estimated that rice self-sufficiency rate can be decreased up to 52.2% by 2010. Based on the analysis of results, policy recommendations for environmentally sound rice farming were suggested as follows: 1) gradual adopting and transferring of environmental rice cultivation method, 2) increasing profitability of rice growing fanners 3) developing the farm level technology specific to Korean farming condition, 4) institutionalization of direct payments for encouraging environmental rice fanning.

• 한국환경보건학회지
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• 제44권6호
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• pp.581-590
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• 2018

Objectives: We aimed to investigate the species composition of fish and benthic macroinvertebrates in the Namgang Dam reservoir and assess the reservoir's ecological quality. Methods: Fish and benthic macroinvertebrates were seasonally sampled around the Namgang Dam reservoir from October 2013 to September 2014. Results: A total of 970 fish specimens were collected for this survey, including 4 orders, 14 families, and 25 species. Fourteen endemic species were observed, including Coreoleuciscus splendidus. The most observed among the endemic species caught was Zacco koreanus (14.4%). A total of 9,093 benthic macroinvertebrates, including 51 families and 92 species, were also found. The predominant species in the study area was Chironomidae sp. 1. Diplonychus esakii, whose habitat is distribution-specific as designated by the Korean National Institute of Environmental Research (NIER), were also observed. A total of 386 specimens were collected of the invasive alien species Lepomis macrochirus, and the percentage of Lepomis macrochirus and Micropterus salmoides made up 42.0% of all specimens collected in the area. Conclusion: The mean ecological score of the benthic macroinvertebrate community (ESB) ranged between 24 and 40, which indicates that the environmental condition of the target sites is somewhat poor. Based on the results of this research, building habitats for benthic macroinvertebrates should be considered, and extermination plans for invasive alien fish species should be prepared.

• 한국입자에어로졸학회지
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• 제10권2호
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• pp.75-82
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• 2014

It is necessary to find out the reaction characteristics of $CaCO_3$ sorbent particles in air and $O_2/CO_2$ atmospheric conditions in order that an in-furnace desulfurization technique can be applied to oxy-fuel combustion system. In this study, rate of change of GMD(geometric mean diameter) and specific surface area of $CaCO_3$ sorbent particles reacted in DTF(drop tube furnace) experimental setup were analyzed to investigate the effect of particle size and humidity on the reaction characteristics of them. In air atmospheric condition, calcination process occurs actively within shorter residence times as the particle size increases. On the contrary, in $O_2/CO_2$ atmospheric condition, a calcination process is delayed as particle size increases. The increment of humidity accelerates calcination process in an air atmospheric condition and increase rate of calcination in an $O_2/CO_2$ atmospheric condition.

• 유기물자원화
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• 제28권1호
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• pp.65-72
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• 2020

본 연구는 초기 식종슬러지 종류별 CO₂의 생물학적 바이오메탄 생산 적용 가능성을 비교를 위해 국내 혐기성 소화조로부터 획득한 식종미생물을 종류에 따라 Specific methanogenic activity (SMA) test를 수행한 결과이다. 36일간의 실험 결과 CH₄ yield는 2,434-2,051mL CH₄/g COD의 범위를 얻었고 생산된 가스 내 CH₄ 분압은 맥주공장과 음식물류 폐기물 식종슬러지에서 가장 높은 89.3-91.9% CH₄ 분포를 보인 반면 하수슬러지 식종슬러지로부터 가장 낮은 효율을 나타냈다. 반응조의 CH₄ production rate/CO₂ consumption rate 비교를 통해 CH₄전환 속도 및 CO₂소비율의 간접적 물질 수지 비교가 가능했으며 SMA test 실험 기간 중 반응조 내 아세트산의 농도의 검출이 확인되었다. 이는 식종슬러지 내부의 잔류 유기물들의 분해, 식종미생물의 사멸 및 이들의 분해, Homoacetogenic bacteria의 활성에 의해 반응조 내 Metabolic pathway가 부분적으로 Hydrogenotrophic methanogenesis 단계에서 Acetoclasctic methanogenesis로의 변환됨에 따른 결과로 사료된다.

• 한국환경보건학회지
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• 제29권3호
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• pp.79-85
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• 2003

The purpose of this study was to disclose the manufacturing process of activated carbon using coal. It investigated the influences on the physical properties that were manufactured activated carbon by using anthracite coal, bituminous coal under carbonizated and activated condition. The adsorption capacities of organic material were superior when the ash content was lower 5∼10%, and the iodine value was about 1,000 mg/g, the adsorption capacity decreased rapidly when ash content was over 15%. The manufactured activated carbon were found characteristics such as the iodine value was over 1,031 mg/g, the specific surface area was over 1,032 $m^2$/g and the hardness was over 95% under manufacturing conditions which were carbonizated temperature of $600^{\circ}C$( 180 minute), activated temperature of 95$0^{\circ}C$(210 minute) and steam weight of 6 $m\ell$/min.100 g coal.

• 한국축산시설환경학회지
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• 제4권2호
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• pp.183-191
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• 1998

This study was carried out to elucidate the correlation between Germination Index(G.I.) and CO2 emission for evaluation of the maturity of compost products. 13 compost samples was used for this experiment. The G.I. test was carried out on the basis of T-N 200ppm. As a result of this research, we found that CO2 emission method was good simple indicator for evaluation of maturity of compost materials, in spite of G.I. The obtain results are summarized as follows ; 1. The correlation value between the G.I. and the CO2 emission was R2 = 0.776. 2. The correlation value between EC(Electric Conductivity) and G.I. was R2 =0.7. 3. The equation calculated from G.I. and CO2 emission was G.I. = -16.7(InCO2) - 6.87. 4. From these results, we found the possibility of estimation for the value of G.I.(T-N 200ppm) from CO2 emission volume under specific condition.

• 환경위생공학
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• 제15권4호
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• pp.52-58
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• 2000

This study was carried out to investigate the contents of heavy metals with respect to the depth, particle size and Tessier et al. method in surface sediment of the Nakdong river. The contents of Cd, Cu & Pb were high or similar with increasing depth, but Mn & Zn were high to middle depth. Generally, the contents of heavy metals were found to be high as the particle size become more small and more deep. Because the more particle size was small, the specific surface area was large, the contents of heavy metals was high for increasing affinity. It was estimated that the types of heavy metals contained in surface sediment by Tessier et al. method was dissimilar with anaerobic condition, pH and degradation of organic matter, etc.

• 한국환경보건학회지
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• 제16권1호
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• pp.45-53
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• 1990

To investigate the effect of cultural condition on the aflatoxin production of Aspergillus flayus ATCC 15517, mixed culture with Aspergillus niger, better kind of media and size of Cultural vessels were examined. YES medium was better than SLS medium for this study. Small scale test tube culture was showed the possibility to simply examine the growth, total acidity, pH and aflatoxin production during cultivation, and also could reduce the second contamination of aflatoxin B1 from large scale broth cultured. Especially ELISA method is simple, sensitive and specific and therefore well suited to small scale of test tube culture. Mixed culture significantly reduced the aflatoxin production of Aspergillus fiavus ATCC 15517 and showed almost 95% inhibition of that level during the incubtation.

• 대한환경공학회지
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• 제34권8호
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• pp.528-532
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• 2012

국내에서 발생되는 인산석고를 매립성토재로 활용 가능성과 수중생물인 담수조류, 해조류 및 물벼룩에 미치는 생물독성을 평가하였다. 인산석고 혼합에 따라 담수조류의 비성장속도는 대체적으로 해조류에 비해 높았으며, PG30 조건에서는 담수조류 성장이 1.7배 정도 컸다. 물벼룩의 경우는 PG50에서는 다소의 영향이 있는 것으로 나타났으나, 평균 독성값(TU)값이 0.3으로 독성기준치 1 이하로 나타나 인산석고에서 발생하는 침출수의 영향이 거의 없는 것으로 여겨진다. 본 연구를 통하여 인산석고를 일반토사와 혼합할 경우, 환경학적으로 폐기물 재활용기준을 만족하고 있는 것으로 나타났으며 3가지 생물의 독성 실험결과 PG30 조건에서 매립성토재로 사용할 경우 생물독성의 영향이 미미할 것으로 판단된다.

• Journal of Ecology and Environment
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• 제36권2호
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• pp.131-140
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• 2013

In Korea, many paddy fields in mountainous area have been abandoned because of their low accessibility and rice price and the abandoned paddy terraces have changed into natural lentic wetlands. To understand the relationship between characteristics of environmental conditions and early development of plant community in abandoned paddy terraces, we investigated at four well-maintained abandoned paddy terraces in 3 different climatic zones in Korea. Soil texture of abandoned paddy terraces was mostly kinds of loam and electric conductivity of soil was also similar among abandoned paddy terraces. On the other hand, contents of nitrogen, phosphorus, potassium, sodium, magnesium, and calcium in soil were relatively low and significantly different among abandoned paddy terraces. Water depth was different within sites and inter-sites. Although environmental conditions including climate, soil condition and water depth were different among abandoned paddy terraces, the compositions of plant communities were relatively similar in all abandoned paddy terraces. 55 dominant taxa out of 141 recorded species were commonly recorded over sites and they were mostly perennial obligate wetland plants and facultative wetland plants. 8 taxa out of 55 dominant taxa occurred at all abandoned paddy terraces with over 10% coverage. Several site-specific species occurred at site, which have some area with deep water level. This result indicates that early development of plant community in abandoned paddy terraces of similar water regime is similar in the entire area of Korea even though environmental conditions such as climate, biogeographic history and soil are different.