• Journal of Environmental Health Sciences
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• v.21 no.4
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• pp.1-9
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• 1995

This study was carried to investigate the biodegradability of phenol in the wastewater with the two sludge blanket-packed bed reactor in series. Each reactor had a dimension of 0.09 m i.d. and 1.5 m height and consisted of two regions. The lower region was a sludge blanket of 0.5 m height and the upper region was a packed-bed of 1 m height. The packed bed region was charged with ceramic raschig rings of 10 mm i.d., 15 mm o.d. and 20 mm length. The reactors were operated at 35$\circ$C and the hydraulic retention time(HRT) was maintained 24 hours. The synthetic wastewater composed of glucose and phenol as major components was fed into the reactor in a continuous mode with incereasing phenol concentration. In addition, the nutrient trace metals($Na^+, Mg^{2+}, Ca^{2+}, PO_4^{3-}, NH_4^+, Co^{2+}, Fe^{2+}$ etc.) were added for growing anaerobes. The phenol concentration of the effluent, the overall gas production, the composition of product gas, the efficiency of COD reduction and the duration of acclimation period were measured to determine the performance of the anaerobic wastewater treatment system as the phenol concentration of the influent was increased from 600 to 2400 mg//l. Successfully stable biodegradation of phenol could be achieved with the anaerobic treatment system from 600 to 1, 800 mg/l of the influent phenol concentration. The upper level of influent phenol loading was high enough to meet most of the practical requirement. The duration of acclimation increased with the phenol loading. At steady state of the influent phenol concentration of 1800 mg/l, the treatment performance indicated the phenol reduction efficiency of 99%, the COD reduction efficiency of 99% and the gas production rate of 37 l/day. At the influent phenol concentration of 2400 mg/l, however, the operation of the treatment system was noted unstable. While the concentration of methane in biogas decreased with increasing the influent phenol loading, the carbon dioxide was increased. However, the concentration of hydrogen was varied negligibly. The concentration of methane was high enough to be used as a fuel. As a result, it is suggested that anaerobic phenol wastewater treament was economical in the sense of energy recovery and wastewater treatment.

• Journal of Soil and Groundwater Environment
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• v.9 no.4
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• pp.52-61
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• 2004

In order to remediate soils contaminated with oxyanionic As and cationic Zn and Ni through the pilot-scale acid washing, the effectiveness of acid washing and the properties of contaminated soils, fine soil particle and dissolved contaminants were evaluated. $H_{2}SO_4\;and\;H_{3}PO_4$ washing at pH $2{\sim}3$ enhanced the removal of As by the presence of competitive oxyanions and HCl washing effectively removed simultaneously As, Zn and Ni. The effectiveness of soil washing was little enhanced above the critical reaction time, and the carbonate, Fe/Mn oxide and organic/sulfides associated fraction were dominantly removed. The washing of coarse soil particles was highly efficient, but that of fine soil particles($<74{\mu}m$) was recalcitrant due to the enrichment with contaminants. Moreover, the physical separation of fine particles($<149{\mu}m$) enhanced the overall efficiency of soil washing. Therefore, both chemical extraction and separation of fine soil particles showed the high effectiveness of soil washing in the intersection point to minimize the amount of fine soil particles and to maximize the chemical extraction of contaminants.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.185-185
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• 2012

중공 발광 나노 물질은 특유의 구조적 특성(낮은 밀도, 높은 비표면적, 다공성 물질, 낮은 열팽창계수 등)과 광학적 성질을 이용하여 디스플레이 패널, 광결정, 약물전달체, 바이오 이미징 라벨 등의 다양한 적용이 가능하다. 이러한 적용에 있어 균일한 크기와 형태의 중공 입자는 필수 조건으로 여겨진다. 지금까지 합성된 중공 발광 입자에는 BaMgAl10O17 : Eu2+-Nd3+, Gd2O3 : Eu3+, $EuPO_4{\cdot}H_2O$과 같은 것들이 있으나 크기 조절이 어렵고, 그 균일성이 확보되지 못하였다. 균일한 크기의 중공 발광 입자를 만들기 위해 SiO2나 emulsion을 템플릿으로 이용하여 황화카드뮴, 카드뮴 셀레나이드 중공 입자를 합성한 예가 있으나, 양자점의 독성으로 인하여 바이오분야 응용에는 적합하지 않다. YAG는 모체로써 형광체에서 가장 많이 이용되는 물질로, 화학적 안정성과 낮은 독성, 높은 양자 효율 등 많은 장점을 갖고 있다. 특히 세륨이 도핑된 YAG형광체의 경우 WLED, 신틸레이터, 바이오산업에 적용이 가능하다. 그러나 지금까지 중공 YAG:Ce3+형광체를 합성한 예가 없었다. 본 연구에서는 단분산 수화 알루미늄 (Al(OH)3) 입자 위에 세륨이 도핑 된 이트륨 베이직 카보네이트 ($Y(OH)CO_3$)를 균일하게 코팅한 후 열처리를 하여 균일한 크기의 Y3Al5O12:Ce3+(YAG) 중공 입자를 합성하였다. 열처리 온도에 따른 고분해능 투과 전자 현미경(HRTEM), X-선 회절(XRD), 고분해능 에너지 분광법(HREDX) 분석결과, 중공 YAG: Ce3+입자는 Kirkendall 효과에 의해 형성됨을 확인하였다. 전계방사형 주사 전자 현미경(FE-SEM) 측정을 통해, 열처리 후에도 입자의 크기와 형태가 균일함을 확인하였으며, 공초점 현미경 관찰을 통해 중공 형태를 명확히 확인 할 수 있었다. Photoluminescence (PL) 분광법과 형광 수명 이미징 현미경(FLIM)을 이용한 광 특성 분석결과, 합성된 입자는 400-500 nm에서 흡수 파장 (456 nm에서 최대 강도)과 500-700 nm 범위의 발광 파장(544 nm에서 최대 강도)을 나타냈고, 상용 YAG: Ce3+(70 ns)에 준하는 74 ns의 잔광 시간(decay time)이 측정되었다. 단분산 수화 알루미늄 입자의 크기를 조절하여 최종 합성된 YAG: Ce3+의 크기를 조절할 수 있었다. 지름 약 600 nm의 Al(OH)3를 사용한 경우, $1,300^{\circ}C$에서 열처리를 한 후 평균 지름 590 nm의 중공입자를 합성하였고, 약 170 nm의 Al(OH)3를 이용하여, 더 낮은 온도인 $1,100^{\circ}C$에서의 열처리를 통해 평균지름 140 nm의 중공 YAG: Ce3+입자를 합성하였다. 본 연구를 통하여 합성된 균일한 크기의 YAG 중공입자는 LED와 같은 광전변환 소자 및 다기능성 바이오 이미징 등의 나노바이오 소자 분야에 활용될 수 있음이 기대된다.

• Proceedings of the Korea Society for Simulation Conference
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• 1997.04a
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• pp.114-114
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• 1997

항만개발 사업은 매립이나 준설과 같은 해안선과 해저지형을 변화시키는 공사가 이루어지며 이는 조석조류 현상의 변화를 유발하게 된다. 특히 해안지형이 복잡한 항만이나 하구에서는 변화정도가 크게 나타나며 방파제나 선박접안 시설과 같은 항내 구조물을 축조 할 경우에도 조석조류 변화가 야기된다. 조석조류 현상의 변화는 해양 수질과 생물상에 영 향을 줄뿐만 아니라 인접한 육지에 이르기까지 크다란 피해를 유발할 수가 있다. 창조시 해 수를 육지로 범람하게 하거나 퇴적이나 침식조건을 변화시킬 수도 있으며 오염물질이 외해 로 확산되는 과정을 방해하고 해양생물의 서식조건을 악화시켜 부근 해역의 어업에 피해를 유발할 수도 있다. 또한 해안 공사 과정에 해수로 유입되는 토사나 항만 이용시에 배출되는 폐수 등이 항내 수질과 생태계를 변화시킬 수 있다. 따라서 조석조류와 수질변화를 사전에 예측하고 이를 최소화하는 방안이 강구되어야 한다. 조석조류와 수질 변화를 사전에 예측하 는 방법으로 축소모형 실험과 컴퓨터 시뮬레이션이 사용된다. 축소모형 실험은 현장을 재현 하는데 많은 경비와 시간이 소모되며 예측에 한계가 있다. 반면에 컴퓨터 시뮬레이션은 대 상해역의 지형과 조류 그리고 수질특성에 적합하게 모델을 개발할 경우 예측력이 매우 높기 때문에 현재 가장 널리 이용되고 있다. 본 연구는 유한 요소법에 기초하여 미국 공병단 (United States Army Corps of Engineers)에서 개발한 TABS-2 모델을 이용하여 온산항에 서 시행되는 부두건설에 따른 조석조류 및 수질변화를 시뮬레이션하였다. 측정된 자료로 모 델 계수를 보정하고 검증하였으며 항내 매립과 준설이 이루어질 때 나타나는 조위와 조속변 화를 예측하였다. 매립과 준설공사시 유출되는 토사가 조석조류현상에 따라 이동 확산되는 범위와 농도분포를 예측하였다.ophobic components)은 75~80%, 친수성 물질(hydrophilic components)은 30~33%정도의 분포를 보였고, 전염소 및 전오존 공정을 거친 처리수에서는 각각 62.2-62.8%, 43.9~49.0% 및 50~ 55%, 40~57% 정도의 분포를 보였다. 그리고 웅집-침전을 거친 처리수에서는 그 분포가 77~82%, 24-48%였다. 전주리 공정을 통하여 소수성 물질(byoghobic components)의 분포가 감 소하는 것을 볼 때 전염소 및 전오존 처리가 용존유기물의 응집에는 오히려 역 효과를 나타내는 것으로 판단된다. 것으로 판단된다.여 황토 2g에 대하여 Hieltijes and Lijklema 방법에 의해 Adsorbed-p, Nonapatite inorganic-P(NAI-P), Apatite-p, Organic-P로 구분하여 분석하고, 총인(Total Phosphorus)을 Standard Methods에 따라 Persulfate digestion후 0.45 m membrane 여지 여과하여 여액에 대해 PO3-4-P의 농도를 Ascorbic Acid 법으로 측정한 결과, NAI-P가 가장 큰 비율을 차지하였고, 부원료로 첨가된 금속 양이온 중 Fe3-이온이 흡착에 기여하는 정도가 가장 큰 것으로 평가되었다.다당류 T-AS의 보체 활성화 기작은 classical과 alternative complement pathway의 양 경로를 통해 활성화 되었다. T-AS 분획은 mouse내의 특정 혈청단백을 증가시켰으며, 항체 생성능의 증가가 관찰되어 effect T 세포의 활성화가 나타나고 있음을 알 수 있었다. T-AS는 생체내 투여시에 대식세포의 탐식능이 증진되었으며, 대식세포 기능 저해제에 의한 대식세포의 기능 저해 현상이 회복되었다. 이와 같은 결과들로부터, T-AS의 항암 활성은 활성

• The Korean Journal of Mycology
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• v.10 no.1
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• pp.33-39
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• 1982

Carpophores of ten Korean strains of Lentinus edodes (Berk.) Singer, an antitumor polysaccharide producing fungus, were extracted with 0.1N NaOH solution. The extracts were dialized for seven days in distilled water and lyophilized to produce crude polysaccharide powders. Thus obtained crude polysaccharide samples were assayed for sugar contents by colorimetric method with anthrone reagent. Among ten strains examined Lentinus edododes-DMC7 was found to be the richest strain in polysaccharide content of carpophores. By shake culture experiment for biomass production, L. edodes-DMC7 was found to be the second most productive strain among seven strains examined. Cultural characteristics of L. edodes-DMC7 were investigated by shake culture method. The best result was obtained when L. edodes-DMC7 was cultured in the medium containing glucose 8g, starch 80g, yeast extract 12g, $KH_2PO_4\;0.87g,\;MgSO_4{\cdot}7H_2O\;O.5g,\;CaCl_2\;0.3g,\;FeSO_4{\cdot}7H_2O\;10mg\;ZnSO_4{\cdot}7H_2O\;4mg,\;CuSO_4{\cdot}5H_2O\;lmg,\;MnCl_2{\cdot}4H_2O\;7mg\;per\;11\;at\;28^{\circ}C$, 180 rpm, for 12 days. Thus thirty-three grams of dry mycelia was obtained per one liter of medium.

• Korean Journal of Ecology and Environment
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• v.37 no.4 s.109
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• pp.436-447
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• 2004

Wetland plants have evolved specialized adaptations to survive in the low-oxygen conditions associated with prolonged flooding. The development of internal gas space by means of aerenchyma is crucial for wetland plants to transport $O_2$ from the atmosphere into the roots and rhizome. The formation of tissue with high porosity depends on the species and environmental condition, which can control the depth of root penetration and the duration of root tolerance in the flooded sediments. The oxygen in the internal gas space of plants can be delivered from the atmosphere to the root and rhizome by both passive molecular diffusion and convective throughflow. The release of $O_2$ from the roots supplies oxygen demand for root respiration, microbial respiration, and chemical oxidation processes and stimulates aerobic decomposition of organic matter. Another essential mechanism of wetland plants is downward water movement across the root zone induced by water uptake. Natural and constructed wetlands sediments have low hydraulic conductivity due to the relatively fine particle sizes in the litter layer and, therefore, negligible water movement. Under such condition, the water uptake by wetland plants creates a water potential difference in the rhizosphere which acts as a driving force to draw water and dissolved solutes into the sediments. A large number of anatomical, morphological and physiological studies have been conducted to investigate the specialized adaptations of wetland plants that enable them to tolerate water saturated environment and to support their biochemical activities. Despite this, there is little knowledge regarding how the combined effects of wetland plants influence the biogeochemistry of wetland sediments. A further investigation of how the Presence of plants and their growth cycle affects the biogeochemistry of sediments will be of particular importance to understand the role of wetland in the ecological environment.

• Journal of Life Science
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• v.18 no.10
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• pp.1377-1383
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• 2008

A bacterium producing non- or partially digestible dextran was isolated from kimchi broth by enrichment culture technique. The bacterium was identified tentatively as Leuconostoc sp. strain SKY. We established the response surface methodology (Box-Behnken design) to optimize the principle parameters such as culture pH, temperature, and yeast extract concentration for maximizing production of dextran. The ranges of parameters were determined based on prior screening works done at our laboratory and accordingly chosen as 5.5, 6.5, and 7.5 for pH, 25, 30, and $35^{\circ}C$ for temperature, and 1, 5, and 9 g/l yeast extract. Initial concentration of sucrose was 100 g/l. The mineral medium consisted of 3.0 g $KH_2PO_4$, 0.01 g $FeSO_4{\cdot}H_2O$, 0.01 g $MnSO_4{\cdot}4H_2O$, 0.2 g $MgSO_4{\cdot}7H_2O$, 0.01 g NaCl, and 0.05 g $CaCO_3$ per 1 liter deionized water. The optimum values of pH and temperature, and yeast extract concentration were obtained at pH (around 7.0), temperature (27 to $28^{\circ}C$), and yeast extract (6 to 7 g/l). The best dextran yield was 60% (dextran/g sucrose). The best dextran productivity was 0.8 g/h-l.

• Korean Journal of Soil Science and Fertilizer
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• v.2 no.1
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• pp.53-68
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• 1969

The nutriophysiological response of rice plant to root environment was investigated with eye observation of root development and rhizosphere in situation. The results may be summarized as follows: 1) The quick decomposition of organic matter, added in low yield soil, caused that the origainal organic matter content was reached very quickly, in spite of it low value. In high yield soil the reverse was seen. 2) In low yield soil root development, root activity and T/R value were very low, whereas addition of organic matter lowered them still wore. This might be contributed to gas bubbles around the root by the decomposition of organic matter. 3) Varietal difference in the response to root environment was clear. Suwon 82 was more susceptible to growth-inhibitine conditions on low-yield soil than Norin 25. 4) Potassium uptake was mostly hindered by organic matter, while some factors in soil hindered mostly posphorus uptake. When the organic matter was added to such soil, the effect of them resulted in multiple interaction. 5) The root activity showed a correlation coeffieient of 0.839, 0.834 and 0.948 at 1% level with the number of root, yield of aerial part and root yield, respectively. At 5% level the root-activity showed correlation-coefficient of 0.751, 0.670 and 0.769 with the uptake of the aerial part of respectively. N, P and K and a correlation-coefficient of 0.729, 0.742 and 0.815 with the uptake of the root of respectively N.P. and K. So especially for K-uptake a high correlation with the root-activity was found. 6) The nitrogen content of the roots in low-yield soil was higher than in high-yield soil, while the content in the upper part showed the reverse. It may suggest ammonium toxicity in the root. In low-yield soil Potassium and Phosphorus content was low in both the root and aerial part, and in the latter particularly in the culm and leaf sheath. 7) The content of reducing sugar, non-recuding sugar, starh and eugar, total carbohydrates in the aerial part of plants in low yield soil was higher than in high yield soil. The content of them, especially of reducing sugar in the roots was lower. It may be caused by abnormal metabolic consumption of sugar in the root. 8) Sulfur content was very high in the aerial part, especially in leaf blade of plants on low yield soil and $P_2O_5/S$ value of the leaf blade was one fifth of that in high yield soil. It suggests a possible toxic effect of sulfate ion on photophosphorization. 9) The high value of $Fe/P_2O_5$ of the aerial part of plants in low yield soil suggests the possible formation of solid $Fe/PO_4$ as a mechanical hindrance for the translocation of nutrients. 10) Translocation of nutrients in the plant was very poor and most nutrients were accumulated in the root in low yield soil. That might contributed to the lack of energy sources and mechanical hindrance. 11) The amount of roots in high yield soil, was greater than that in low yield soil. The in high-yield soil was deep, distribution of the roots whereas in the low-yield soil the root-distribution was mainly in the top-layer. Without application of Nitrogen fertilizer the roots were mainly distributed in the upper 7cm. of topsoil. With 120 kg N/ha. root were more concentrated in the layer between 7cm. and 14cm. depth. The amount of roots increased with the amount of fertilizer applied.

• Applied Biological Chemistry
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• v.18 no.1
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• pp.16-22
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• 1975

This experiment was carried out to investigate the physiological characteristics of two original yeasts, 5-Y-5 and 6-Y-6, which selected from 24 Takju yeasts and three mutants, 30-24,30-81 and 40-27. induced from two original yeasts by the irradiation of UV light. The results were summarized as follows. 1) Alcohol tolerances of three mutants were decreased in some degree as compared with those of original yeasts. 2) Tolerances of lactic and citric acids of acid producing mutant 30-81, was increased than those of original yeasts. 3) In the case of using ammonium sulfate as a nitrogen source, two original yeasts and three mutants required Ca-pantothenate as a essential growth factor and four strains of yeasts except the mutant, 30-81, required biotin as a stimulated growth factor, When asparagine was used as a nitrogen source, two original yeasts and three mutants showed the same as above result but the stimulated effect of biotin was far less. 4) Propagation powers of the mutants were weaken than those of original yeasts, particular that of acid producing mutant, 30-81, was the weakest in the three mutants. 5) The optimum temperature for fermentation of original yeasts were $30^{\circ}C\;to\;35^{\circ}C$ but three mutants were $25^{\circ}C\;to\;30^{\circ}C$. 6) The optimum pH for fermentation of original yeasts were pH 5 to 6, and there is no appreciable difference between original yeasts and three mutants. The fermentation power of mutant,30-81, was decreased more rapidly than those of other mutants according to approach neutral. Three mutants were more sensible to heat than original yeasts. 7) Two original yeasts and three mutants were inhibited more over 20 percent of sugar for fermentation and three mutants were more sensible to sugar concentration than original yeasts.

• Korean journal of applied entomology
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• v.16 no.4 s.33
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• pp.199-208
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• 1977

Activities of various hydrolytic enzymes produced by three plant pathogenic fungi, Sclerotium rolfsii Sacc., Sclerotinia sclerotiorum (Lieb.) deBary and Helminthosporium sigmoideum var. irregulare Crallery et Tullius, were measured. Activties and amounts of the enzymes in mycelia, cultural filtrates, and sclerotia(except of sclerotia of H. sigmoideum var. irregulare) were estimated at various pH levels in order to find out optimal pH for their enzymatic activities. Enzymes such as cellulase (ex), invertase, xylanase, $\beta-amylase$, polymethylgalacturonase, polygalacturonase, phosphatase and protease were estimated. Culture solution for production of enzymes was prepared by adding of 10g, D-glucose, 1.3g $NH_4NO_3,\; 0.5g\; MgSO_4,\;7H_2O,\; and\; 1.0g\; KH_2PO_4$ into 1 liter of potato decoction plus 2ml of micro element solution consisting of 0.2mg. Fe, 0.2mg Zn, and 0.1mg Mn as the sulphates into 1 liter of distilled water. All tested mycelia and cultural filtrates were obtained from the cultures incubarted in previous solution for ten days at $25^{\circ}C$, and sclerotia were harvested from PDA plates of 3. days old, The crude enzyme solutions were prepared according to the method of Miyazaki etal. Ten days after incubation, activities of Cx produced by Scl. sclerotiorum were higher than those of the other fung and each of Cx from three fungi showed different pH optima, such as S. rolfsii and Scl. schlerotiorum in acid side (around pH 3.0), H. sigmoideum var. irregulare in neutral side (around pH 6.3). Invertase activities of S. rolfsii were 20 times higher than those of the other fungi in all samples. All tested fungi, however, showed no significant difference between the enzymatic activities of their cultural filtrate and mycelia and the activities in sclerotia of S. rolfsii and Scl. sclerotiorum were hardly recognized. There were multiple peaks on the xylanase activity curves of three fungi in terms of pH values. High activities of the xylanase were revealed in sclerotia of S. rolfsii and Scl. sclerotiorum, and in mycelia of H. sigmoideum var. irregulare. The highest activities of $\beta-amylase$ were shown both in mycelia and cultural filtrate of H. sigmoideum var. irregulae among the tested fungi, and their optimal pH was 6.2 in both mycelia and cultural filtrate. In the S. rofsii and Sel. sclerotiorum, however, the activities of cultural filtrates were higher than those of the other fungi, and optimal pH was 3.0 and 6.2 for cultural filtrate and both mycelia and sclerotia, respectively. Activities of PMG were high in cultural filtrates of all tested fungi, especially in Scl. sclerotiorum and H. sigmoideum var. irregulare. Mycelia of themalso showed the considerable activities. Optimal pH for enzymatic activities were variable with thekind of fungi or with the samples measured. The highest activities of PG were presented by mycelia of S. rolfsii and Scl. sclerotiorum. $9.l\mu /min.\; and\; 9.5\mu g/min.$, respectively. Optimal pH for activity of PG in mycelia was around 4.5 in S. rolfsii and around 3.0 in Scl. sclerotiorum. Phosphatase of S. rolfsii and Scl. sclerotiorum was more active in acid side (optimal PH3. 5) and that of H. sigmoideum var. irregulare showed one peak each in acid, neutral and alkaline side. But the highest peak was at pH 9.5. Protease of all tested fungi was more active at pH 10.0, especially that of the cultural filtrate of H. sigmoideum var. irregualre.