• Journal of the Korea Organic Resources Recycling Association
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• v.11 no.1
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• pp.132-137
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• 2003

This study was carried out to investigate removal character of nitrogen and phosphorus with injection time of acetic acid on SBR, which is one of the biological treatment process. Wastewater used in experiment period was swine wastewater with character, relatively lower organic material concentration than nitrogen concentration. In the experiment with injection time of acetic acid, run 1 wasn't injected acetic acid during the anoxic period, and run 2 was injected intermittently acetic acid during the anoxic period of 15 hours. And run 3 was injected intermittently during the anoxic period of 3hours from end of wastewater filling. And filing time of the wastewater was 20hour from run 1 to run 3. In the study, the highest removal efficiency of organic and nitrogen were obtained by the operating condition of Run 2(the ratio of mixing/aeration time : 16.5/5.5, injection time of acetic acid : 15hours) and T-P was obtained by the operation condition of Run 3(the ratio of mixing/aeration time : 16.5/5.5, injection time of acetic acid : 3hours),and removal efficiency of $BOD_5$, $COD_{Mn}$, $COD_{Cr}$, T-N and T-P in the treated water was 96.1%, 87.7%, 90.6%, 86.6% and 84.5%, respectively.

• Korean Journal of Agricultural and Forest Meteorology
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• v.1 no.1
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• pp.29-35
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• 1999

Soil structure and organic matter have been known to strongly affect water flow and solute transport, yet little information is available concerning soil hydraulic properties related to soil physical and chemical properties in the forest site. The purpose of this study was to quantify the spatial variability and spatial correlation of the measured parameter values from the plots established with the rainfall simulator on Japanese larch(Larix leptolepis) dominated site in Kwangju. Kyunggi-Do. Measurement of soil water flux and retention were made with the inherent soil texture, soil structure, and organic matter. The method was based on the observation that when water was applied at a constant rate to the soil surface on each plot. The method was simple to apply and consists of following steps: (i) Wet the soil from a rainfall simulator with several known discharge rates on a relatively leveled soil surface with and without organic matter. (ii) Once the borders of the ponded zone were steady, saturated hydraulic conductivity( $K_{s}$) and the matric flux function(F) was evaluated from a regression of flux vs. the reciprocal of the ponded area. A conductivity of the form $K_{i+}$$_1$ $_{c}$= $K_{i}$( $_{c}$) [1-d /dz] where flux continuity implies. For this, continuity of matric potential at the interface at all times are as follows: $_1$( $Z_{c}$) = $_2$( $Z_{c}$) = $_{c}$ for steady state intake from water ponded on the soil surface. Results of this investigation showed the importance of understanding spatial variability in wide differences of water retention and saturated hydraulic conductivity with respect to pore geometry and organic matter contents which influenced the water flux throughout the soil profile.l profile.ile.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.2
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• pp.118-125
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• 2008

Diverse organic amendments available in local areas have been used to improve soil quality in red pepper field and so the need for investigating the soil chemical and biological properties changed by the organic amendments application is increasing. Soil microbial diversities were measured by phospholipid fatty acid (PLFA) and Biolog $EcoPlate^{TM}$. Compost was most effective for improving soil chemical properties including pH, EC, total nitrogen, P, K, and Ca, and bark increased soil organic matter significantly (P=0.05). Compost increased the fatty acids indicating actinomycetes and vascular arbuscular fungi, and ratio of cy19:0/18:1w7c and monounsaturated fatty acids/saturated fatty acids in soils in PLFA analysis. Bark increased soil fungal indicators in PLFA analysis (P=0.05). Principal component analysis of Biolog EcoPlate data and PLFA differentiated the compost- and bark-amended soils from other organic matteramended soils especially the soil incorporated with compost. More researches are needed to use bark for improving soil microbial properties because the soil chemical and microbiological properties caused by compost and bark are significantly different.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.3
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• pp.335-340
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• 2010

This study was conducted to select organic materials (OM) and nitrogen sources in composting of waste mushroom bed from Agaricus bisporus. We examined physio-chemical properties of the organic materials and the mixture ratio for preparing the wasted mushroom bed (M) compost. The carbon content of sawdust was higher than those of rice straw (R) as OM source and the nitrogen content was high in the order of fowl manure (F)>> pig manure (P)> cow manure (C). The compost was prepared to maintain the criteria of above 25% organic matter and then the change of their ingredients was estimated during the process of fermentation. The temperature of waste mushroom bed+pig manure+rice straw (MRP) treatment was varied fast throughout fermentation, on the other hand the temperature of waste mushroom bed+pig manure+sawdust (MSP) treatment was steadily elevated to the middle of composting. The pH of the compost was somewhat high to pH 8.5~9.0 at the early stage, but decreased to 7.5 at the end stage of composting. The content of OM after fermentation was decreased to the level of 19~21% in rice straw, but the sawdust treatment maintained 25~27% organic matter. The waste mushroom bed+fowl manure+rice straw (MRF) treatment, which contains 26.2% organic matter and 0.68% nitrogen, was the highest among them. The volume of compost was reduced to 50% by using rice straw as organic matter, but reduced to 30% by using the sawdust. The contents of heavy metal in the compost were suitable within the legal criteria. The number of microorganisms were higher in the rice straw than those in the sawdust. It was high in the order of fowl manure> pig manure> cow manure. The major groups consisted of aerobic bacteria, gram negative bacteria and Bacillus sp. and their populations after fermentation were increased to $1{\times}10^1{\sim}1{\times}10^2\;cfu\;g^{-1}$ rather than those before fermentation. Therefore we concluded that the waste mushroom bed+fowl manure+sawdust (MSF 3:9:1 v/v/v) treatment was suitable combination for high organic matter and nitrogen source, and the periods of composting were 50~60 days.

• Korean Journal of Microbiology
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• v.51 no.2
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• pp.97-107
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• 2015

Wetlands constitute a transitional zone between terrestrial and aquatic ecosystems and have unique characteristics such as frequent inundation, inflow of nutrients from terrestrial ecosystems, presence of plants adapted to grow in water, and soil that is occasionally oxygen deficient due to saturation. These characteristics and the presence of vegetation determine physical and chemical properties that affect decomposition rates of organic matter (OM). Decomposition of OM is associated with activities of various extracellular enzymes (EE) produced by bacteria and fungi. Extracellular enzymes convert macromolecules to simple compounds such as labile organic carbon (C), nitrogen (N), phosphorus (P), and sulfur (S) that can be easily taken up by microbes and plants. Therefore, the enzymatic approach is helpful to understand the decomposition rates of OM and nutrient cycling in wetland soils. This paper reviews the physical and biogeochemical factors that regulate extracellular enzyme activities (EEa) in wetland soils, including those of ${\beta}$-glucosidase, ${\beta}$-N-acetylglucosaminidase, phosphatase, arylsulfatase, and phenol oxidase that decompose organic matter and release C, N, P, and S nutrients for microbial and plant growths. Effects of pH, water table, and particle size of OM on EEa were not significantly different among sites, whereas the influence of temperature on EEa varied depending on microbial acclimation to extreme temperatures. Addition of C, N, or P affected EEa differently depending on the nutrient state, C:N ratio, limiting factors, and types of enzymes of wetland soils. Substrate quality influenced EEa more significantly than did other factors. Also, drainage of wetland and increased temperature due to global climate change can stimulate phenol oxidase activity, and anthropogenic N deposition can enhance the hydrolytic EEa; these effects increase OM decomposition rates and emissions of $CO_2$ and $CH_4$ from wetland systems. The researches on the relationship between microbial structures and EE functions, and environmental factors controlling EEa can be helpful to manipulate wetland ecosystems for treating pollutants and to monitor wetland ecosystem services.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.32-32
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• 2003

최근 환경오염에 대한 문제가 심각해지면서 인체에 유해한 유기물질의 분해에 대한 관심이 높아지고 있으며 따라서 뛰어난 광촉매 특성을 보이는 타이태니아(TiO$_2$)에 대한 많은 연구가 수행되고있다. 타이태니아가 보이는 결정상 중에는 brookite, anatse, rutile이 있는데 이 중에서 anatse 상이 가장 우수한 광촉매 특성을 나타내는 것으로 알려져 있다. 그러나 anatse 상을 얻기 위해서는 $600^{\circ}C$ 이상의 온도로 열처리를 해야 한다는 문제점이 있으며 광촉매 특성을 향상시키기 위해서는 anantase 나노결정을 제조하여 표면적을 극대화시 키는 것이 요구되고 있다. 본 연구에서는 이러 한 두 가지 문제점을 해결하기 위하여 Polyethylen oxide(PEO)-TiO$_2$ 나노하이브리드를 Sol-Gel공정을 이용하여 합성하였으며 이들에 대한 hot-water treatment를 통하여 10$0^{\circ}C$ 이하의 저온에서 anatase 나노결정상의 분말을 합성하는데 성공하였다. 이는 SiO$_2$-TiO$_2$계 하이브리드에서만 hot-water treatment를 통하여 anatase로 결정화가 가능하다는 기존의 연구결과와 상반되는 결과로서 무기질 성분으로서 TiO$_2$만 존재하는 하이브리드에 대한 hoi-water treatment를 통하여 anatase결정상이 형성될 수 있었다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.184-184
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• 2010

ITO의 전극 패턴에 따른 유기 광기전력 소자의 전기적 특성에 대해서 연구하였다. 소자의 구조는 ITO/PEDOT:PSS(90nm)/CuPc(20nm)/$C_{60}$(40nm)/LiF(0.5nm)/Al(100nm)이고, PEDOT:PSS는 스핀 코팅한 후 $120^{\circ}C$에서 20분간 건조시켰으며, 유기물은 열증착을 하여 제작하였다. ITO 전극의 패턴을 corss-bar type과 island type으로 하여 소자의 특성을 비교하였다. 광원은 500W xenon lamp를 사용하였고, optical density filter로 광원의 세기를 조절하였으며, AM 1.5G의 스펙트럼을 조사하였다. PEDOT:PSS 층을 사용함으로서 유기 광기전력 소자의 효율, 단락 전류, 그리고 개방 전압의 향상을 얻을 수 있었다. ITO 전극 패턴에 따른 광기전력 소자의 특성은 cross-bar type에 비하여 island type의 구조에서 유기 광기전력 소자의 효율이 34% 감소하였다.

• Journal of the Microelectronics and Packaging Society
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• v.5 no.2
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• pp.1-6
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• 1998

B2O3F2를 함유한 Fluormica glass-ceramics 분말과 Potashborosilicate glass 분말을 이용하여 저온소결용 기판을 제조하기 위하여 제조한 그린시트의 특성 및 소결체의 소결 특 성을 평가하였다. 기판 제조용 슬러리를 제조하기 위해 결정화유리분말에 Potashborosilicate glass 분말을 각각 0. 25, 50wt%를 혼용하였다. Doctor blade법으로 그린시트를 제조한후 그 특성을 평가한 결과 건조수축률은 15.2~30.7% 온도상승에 따른 유기물의 탈지온도는 414$^{\circ}C$(2시간)로 선정하였다. 그린시트는 800~120$0^{\circ}C$사이에서 소성하여 소결특성을 평가하였 다. 소결 수축률은 17.5~18.5% 겉보기 기공률은 16.53~20.07%였다.

• Proceedings of the Materials Research Society of Korea Conference
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• 2000.11a
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• pp.80-80
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• 2000

차세대 대화면 평판 디스플레이에서 가장 주목을 받고 있는 디스플레이 소자는 PDP라고 할 수 있다. PDP 패널 제조 공정 기술에서 난해한 공정 중 하나인 투명 유전체 제조 공정은 현재까지 인쇄법에 의한 연구가 주로 진행되어 왔다. 그러나 인쇄법은 여러 번의 인쇄와 건조, 소성이 반복되어야 함으로써 유전체 제조에 있어서 복잡한 제조 공정이므로 대폭 단순화할 필요가 있다. 이에 대한 해결책으로서 제시된 것이 tape casting을 이용한 건식 공정이다. 본 연구에서는 tape casting용 slurry에 포함되는 유기물인 binder, plasticizer, solvent의 변화에 따른 dry film의 특성 및 소성 조건에 따른 유전체 특성에 관하여 조사하였다. PbO-SiO$_2$-B$_2$O$_3$계 유리 분말과 유기 vehicle을 ball mill을 이용하여 분산, 혼합하여 tape casting용 slurry를 제조하고, 이 slurry를 doctor blade법으로 tape를 제조하고 건조한 후 유리기판에 transfer한 후 소성하였다. Slurry의 조건과 소성 조건에 따른 투광성, 표면 조도 및 단면의 미세구조 등 투명 유전체의 특성을 평가하였다.

• Journal of Wetlands Research
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• v.16 no.3
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• pp.355-362
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• 2014

Changes of soil properties due to sedimentation and erosion in the river estuary may lead changes in environmental factors that affect plant growth and distribution, Then habitats in the river estuary that provide various ecological functions can also be influenced. Topsoil samples were analyzed in order to understand the soil properties of important barrier islands and habitat types in the Nakdong river estuary. The samples were obtained from Phragmites communis and Scirpus planiculmis habitats, the tidal flats in the southern area of Eulsukdo, and in Mangeummerydeung, Baekhapdeung, and Doyodeung. Analyses results showed that bulk density, pH, organic matter content and total nitrogen concentration which were directly or indirectly affected by vegetation showed significant difference (p<0.05) with habitat types but no differences in water content and oxidation reduction potential which could be affected by soil texture and showed significant difference among barrier islands. Results suggested that soil properties on barrier islands in the Nakdong river estuary were influenced first by geomorphic changes due to sedimentation and erosion, and then by the presence or type of vegetation. A range of physical and chemical properties were analyzed; soil water content and bulk density (physical properties), and organic content and pH (chemical properties) were correlated with seven other soil properties, at a level of significance higher than 90%. These aspects played an important role in determining overall soil properties in the studied area.