• 설비공학논문집
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• 제19권5호
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• pp.372-378
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• 2007

GHX (Geothermal Heat Exchanger) design which determines the performance and initial cost is the most important factor in ground source heat pump system. Performance of GHX is strongly dependent on the thermal resistance of soil, grout and pipe. In general, GHX design is based on the static simulation program. In this study, dynamic simulation has been peformed to analyze the variation of system performance for various GHX parameters. Line-source theory has been applied to calculate the variation of ground temperature. The averaged weather data measured during a 10-year period $(1991\sim2000)$ in Seoul is used to calculate cooling and heating loads of a building with a floor area of $100m^2$. The simulation results indicate that thermal properties of borehole play significant effect on the overall performance. Change of grout thermal conductivity from 0.4 to $3.0W/(m^{\circ}C)$ increases COP of heating by 9.4% and cooling by 17%. Change of soil thermal conductivity from 1.5 to $4.0W/(m^{\circ}C)$ increases COP of heating by 13.3% and cooling by 4.4%. Change of GHX(length from 100 to 200 m increases COP of heating by 10.6% and cooling by 10.2%. To study long term performance, dynamic simulation has been conducted for a 20-year period and the result showed that soil temperature decreases by $1^{\circ}C$, heating COP decreases by 2.7% and cooling COP decreases by 1.4%.

• The Korean Journal of Ecology
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• 제16권2호
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• pp.191-198
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• 1993

The relationships between microbial activity and disturbance level of soil were investigated from 15 parks in Seoul and undisturbed area. The physico-chemical characteristics of soil and dehydrogenase activity(DHA) as an index of soil microbial activity were analysed. There were ranges of 3.84~7.37 in pH, 9.63~40.33% in moisture content, 3.41~21.49% in organic matter, 0.36~0.79g/g in water holding capacity and 0.03~0.53% in total nitrogen investigated sites. DHA values of soil were 8.64~$146.76{\mu}g/g$ in park soil and 545.14~$1, 198.80{\mu}g/g$ in undisurbed area. DHA of park soil with high traffic density and contamination source from human activities was much lower than that of undisturbed area. DHA was positively correlated with moisture content, organic matter, water holding capacity and total nitrogen.

• 한국미생물·생명공학회지
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• 제22권5호
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• pp.561-563
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• 1994

For the more effective isolation of soil actinomycetes, we have developed HHV (Hair hydrolysate-vitamin) agar medium, containing hair as the sole source of carbon and nitrogen. The HHV agar medium was superior to other media such as colloidal chintin agar, glycerol-arginine agar and starch-casein-nitrate agar, and HV (humic acid-vitamin) agar. The maximum effect of this medium has been shown in hair dry weight 0.4 g/l medium. Of each soil sample, the greatestest number of actinomycetes was isolated from the potato annual planted soil among the tested samp- les. The genus of actinomycetes isolated from the potato annual planted soil sample was identified such 5 group as Stretomyces, Micromonospora, Microbispora, Nocardia and Saccharopolyspora.

• 한국환경농학회지
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• 제24권3호
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• pp.210-214
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• 2005

To reduce effectively cadmium (Cd) phytoavailability by phosphate in mine tailing affected soil, fused and super phosphate (FSP), a main phosphate fertilizer in South Korea, was selected as phosphate source and then applied at the rates of 0, 78, 390, and 780 $P_2O_5kg\;ha^{-1}$. FSP did not decrease Cd extractability and radish Cd uptake, but increased significantly. The effect of Cd supplement and soil negativity increase through FSP application was not significant. Soil pH decreased markedly with increasing FSP application, which increased significantly soil Cd extractability and radish Cd uptake. As a result, phosphate fertilizer for reducing Cd phtyoavailability in heavy metals contaminated soil should be carefully selected as alkaline type.

• 한국토양비료학회지
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• 제47권1호
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• pp.23-27
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• 2014

Nutrient accumulation in surface soil has become a serious problem for cucumber production in greenhouse. However, still in many cases, soil management practices are only focused on maintaining crop yield, regardless of sustainability related with soil chemical properties. This study was conducted to propose a sustainable soil management practice by investigating the impact of cover crop species and nitrogen rate of fertigated solution on cucumber yield and soil chemical properties in greenhouse condition. Rye and hairy vetch were tested as a fallow cover crop, and each amount of urea (1/2, 3/4, 1 times of N fertilizer recommendations), determined by soil testing result, was supplied in fertigation plots as an additional nitrogen source. The result showed that the yield of cucumber was higher in rye treatment than control and hairy vetch treatment. In addition, rye effectively reduced EC and accumulated nutrients from the soil. Meanwhile, N concentration of fertigated solution showed no significant effect on the growth and yield of cucumber. Consequently, these results suggest that it is desirable to choose rye as a fallow catch crop for sustainable cucumber production in greenhouse.

• 미생물학회지
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• 제35권1호
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• pp.65-71
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• 1999

BIOLOG GN microplate를 이용하여 6종의 식생 토양에 따른 토양미생물 군집의 유일탄소원 이용능을 비교 분석하였다. 전체적으로 축합물, 아미노산, 카르복실산 화합물을 잘 이용하였으나, amide의 경우 낮은 이용능을 보였다. 대응분석을 통해 6종류의 식생 토양에 따른 토양미생물 군집은 크게 삼림토양, 초지-경작지토양, 비식생 토양의 3가지 그룹의 대사적 다양성의 차이를 보이는 집단으로 분류되었다. 다차원 척도법 분석을 통해 신갈나무 삼림토양의 미생물 군집은 소나무와 떡갈나무 삼림토양의 미생물 군집과는 또 다른 그룹으로 분리되었다. 이러한 식생토양형에 다른 미생물 군집의 대사 다양성의 차이로 볼 때, 식생의천이에 따라 식생에 영향을 받는 미생물 군집의 대사 다양성 또한 식생의 천이에 대응하여 변화하고 있음을 확인하였다.

• 한국농공학회논문집
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• 제52권5호
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• pp.37-45
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• 2010

Manure recycling as fertilizer is one of solutions for the environmental problem related with livestock manure treatment as well as the ocean dumping ban act prohibiting manure disposal to the ocean. For the manure disposal, forest area can be a candidate place because the area has a wide range of applicable sites. However, the manure application to the forest has a possibility of causing environmental impacts including water quality problems due to nutrient loading. Therefore it is necessary to investigate water quality impact from manure disposal to the forestry plantation. In this study, ground and soil water quality had been monitored in the bio-circulation experimental forest where low concentration liquid manure (LCLM) was applied. Soil and groundwater samples were collected and analyzed weekly from April to October in 2008 and 2009. The mean and variation of NO3-N concentration in soil water of LCLM treatment places showed higher concentration than the reference places declining during growing season. In the case of groundwater from monitoring well in the downstream of disposal site, the $NO_3$-N concentration was 3.59 mg/L in 2008 and 3.26 mg/L in 2009 in average showing higher concentration than the reference well although the concentration was not exceed the national drinking water standard. To investigate the source of nitrate, $\delta^{15}N$ isotope analysis was also implemented. Its result showed that the LCLM application could be the nitrate source requiring further long-term monitoring soil and water quality.

• 한국환경복원기술학회지
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• 제14권3호
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• pp.15-32
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• 2011

This study was carried out to investigate the soil characteristics and propose the management for the Monument Beobsoo Marsh, Korea. The soil properties of O.M, $Ca^{2+}$, $Na^+$ and CEC were higher and the soil properties of pH_{1:5}$ and $P_2O_5$ were lower the studied sites than other marsh sites in Korea. Although the Heavy metals such as Pb, Hg, Cd, Cu, Zn, Cr and As were lower compare to the safety standard of soil pollution in Korea, the overall conservation management plan based on long-term monitoring should be considered just because it varied by the point and non-point source pollution within the studied marsh. The source of water pollution varied due to non-point polluting origins such as sewage inlet, degraded terrain for agriculture, fishing sites, sites of removed water grasses, pesticides, chemical fertilizers, as well as fallen leaves. The creation of an artificial marsh is recommended due to the soil environment of the studied sites may be changed owing to the accumulated contaminants from the sources of both of point or non-point contaminants. The establishment of the zones of core, buffer and transition which is basic management structure of the UNESCO MaB could be applied to manage the studied site. Simultaneously the promotion of voluntary participation and education of the local residents are needed.

• 공업화학
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• 제25권1호
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• pp.27-33
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• 2014

석유누출 사고로 인해 토양과 지하수 오염이 점차 증가되면서, 토양환경에 대한 중요성이 늘고 있다. 토양오염은 다른 환경오염에 비해 많은 정화비용과 긴 정화기간이 요구된다. 이런 이유로 토양오염이 발생되면, 어떤 오염물질에 의해 토양이 오염되었으며, 토양정화의 책임이 있는 오염자가 누구인지 법적 분쟁이 많이 발생되고 있다. 본 연구에서는 토양오염을 발생시킬 수 있는 항공유에 대한 물성 분석과 함께 항공유 내의 특정 첨가제를 분석함으로써 등유와 항공유의 구분법을 찾아내었다. 특히 발색제에 의해 등유 내 화학적 식별제만 발색되었으며, GC-MS 분석결과 항공유에서만 산화방지제와 금속불활성제가 분석되었다. 이는 추후 항공유에 의한 토양오염 야기 시, 어떤 석유제품에 의한 오염인지 쉽게 판단이 가능할 것이다.

• 미생물학회지
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• 제35권1호
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• pp.72-77
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• 1999

BIOLOG GN microplate를 이용한 유일탄소원의 이용능 비교를 통한 대사적 유사성과 16S rDNA 의 PCR 증폭산물의 제한효소 지문 분석에 따른 유전적 유사성을 5종의 식생토양에 따른 토양미생물 군집을 대상으로 비교하였다. 16S rDNA를 증폭하여 제한효소 지문을 분석한 결과, 토양으로부터 직접 추출하여 증폭한 토양세균 군집의 16S rDNA의 유전적 유사도는 BIOLOG GN microplate를 이용한 대사적 구조와 일치하는 경향을 보았다. 그러나 배양된 종속영양세균 군집의 다양성과는 유전적 유사도가 매우 낮게 나타났다.