• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.3
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• pp.225-237
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• 1990

Various chemical constituents were measured from April to August 1988 at the down-ward 20 stations of Keum River, which is located in the Midwest of Korea, to understand the characteristics of water quality with respect to spatio-temporal variations of each constituent. The 24-hrs continuous measurements with 2-hrs interval were made simultaneously at station 2 near the estuary weir and station 9(Ganggyeong) of 35 km upstream from the weir in April. By the results observed for one day in April at station 2, salinity has a range of $7.88\~22.14\%_{\circ}$ and its temporal variability is identical to the pattern of tidal cycle in the neigh-bouring Kunsan Harbor. However, turbidity shows relatively high values only at an interval of 4~5 hours after the lowest salinity time, though hourly fluctuation of pH is very small. Silicate and dissolved inorganic nitrogen have inversively linear correlationships with salinity, implying the concentration of the two nutrients strongly regulated by estuarine mixing of sea and river waters. In contrast, phosphate sustains roughly a constant level over a wide salinity range and distinctly lower values than those corresponding to nitrate in the oceans. Such distributions of phosphate have been observed in some estuaries, and interpreted as driven by removal of dissolved phosphate into bottom sediments and the bufforing of phosphate by particulate matter. COD values at station 2 are relatively high in day-time(particularly afternoon) and in high-salinity periods. At station 9, saltwater intrusion was never found but water level changed to the extent of 2.5 m for one day. Although each parameter at this station exhibits very slight variations in their abundance for 24 hours compared with station 2, the contents of COD, silicate and ammonia are significantly higher than at station 2. Concentration of suspended matter is relatively high in the brackish water region up to $\~20$ km above the river mouth, probably due to strong tidal stirring of the bottom de-posits. Also, relatively high pH, COD and $O_2$ saturation at the upward stations of $40\~50$ km from the weir are presumably attributable to active photosynthesis of plants in the region. In general, COD and nutrients except phosphate are higher values at the upper stations than in the estuary zone, and show the highest abundances in July nearly at all stations. Finally, in the estuarine region tidal mixing of sea-river waters seems to be an important factor controlling the distributions of turbidity, COD, silicate and nitrate as well as salinity. However, water quality in the upward fresh-water zone is remarkably variable according to months or seasons.

• The Korean Journal of Nuclear Medicine
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• v.38 no.4
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• pp.325-329
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• 2004

Purpose: Usefulness of mouse liver S9 fraction was evaluated for the measurement of the metabolites in the in vitro metabolism study of $^{18}F$-labeled radiotracers. Materials and Methods: Mouse liver S9 fraction was isolated at au early step in the course of microsome preparation. The in vitro metabolism studies were tarried out by incubating a mixture containing the radiotracer, S9 fraction and NADPH at $37^{\ciirc}C$, and an aliquot of the mixture was analyzed at the indicated time points by radio-TLC. Metabolic defluorination was further confirmed by the incubation with calcium phosphate, a bone mimic. Results: The radiotracer $[^{18}F]1$ underwent metabolic defluorination within 15 min, which was consistent with the results of the in vivo method and the in vitro method using microsome. Radiotracer $[^{18}F]2$ was metabolized to three metabolites including $4-[^{18}F]fluorobenzoic$ acid within 60 min. It is likely that the one of these metabolites at the origin of radio-TLC was identical with the one that obtained from the in vivo and in vitro (microsome) method. Compared with the in vitro method using microsome, the method using S9 fraction gave a similar pattern of the metabolites but with a different ratio, which can be explained by the presence of cytosol in the S9 fraction. Conclusion: These results suggest that the findings of the in vitro metabolism studies using S9 fraction can reflect the in vivo metabolism of novel radiotracers in the liver. Moreover, this method can be used as a tool to determine metabolic defluorination along with calcium phosphate absorption method.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.2
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• pp.137-143
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• 1991

This research was conducted to investigate the treatment effects of the experimental product of an oxidatively treated animal wastes such as feces of cow and pig on the growth and yield of corn, soil fertility parameters, nutrient uptake by corn, and in situ dry matter digestibility. The results are summarized as follows. (1) Growth of corn was favored by treatment of the experimental products as compared to the control. Highest yields were obtained at treatment levels of 2,000 and 2,500kg/10a for the experimental products derived from cow and pig feces, respectively. (2) The contents of soil organic matter were increased 7-41% and 4-60% with treatments of experimental products from cow and pig feces, respectively, as compared to the control. The available soil phosphorus levels were increased significantly with the treatments. Treatment of product from the cow feces resulted in a slight increase of the potassium adsorption ratio (KAR). (3) No significant difference was observed in uptake of total nitrogen and phosphorus between the treatments and the control. Uptake of cation by corn was in the order of $K_2O$ >CaO>MgO. (4) In situ dry matter digestibility ratio was increased with Incubation time. However, no significant difference in digestibility was detected for the corn samples produced by treating different levels of the experimental products.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.10
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• pp.709-716
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• 2011

Effect of inorganic coagulants dosing on the performance of electro-chemical process was studied when treating hospital wastewater having low electrolyte concentration. It is thought that adding inorganic coagulants caused increase in concentration of electrolyte and this caused increase in free chloride concentration and consequently, caused increase in indirect oxidation effect. Thus, COD removal efficiencies more than doubled in percentage terms at the 2 hrs of reaction time and current density of $1.76A/dm^2$ compared with the results obtained from the parallel experiments without adding inorganic coagulants. T-N removal efficiencies approximately doubled in percentage terms at the 2 hrs of reaction time and 700 ppm of coagulants addition and applied current density of $1.76A/dm^2$ due to the increase of free residual chlorine such as HOCl caused by increase of electrolyte concentration through the addition of inorganic coagulants. Under the same experimental condition, more than 90% of T-P removal efficiencies was obtained. The reason can be explained that increase of chemical adsorption rate between phosphate and insoluble metal compounds caused by dissolved oxygen generated from anode by the increased electrolyte concentration through inorganic coagulants addition make a major role in improving T-P removal efficiencies. It can be concluded that inorganic coagulants addition as the supplemental agent of electrolyte is effective way in improving organic and nutrient salt removal efficiency when treating hospital wastewater having low electrolyte concentration.

• The Korean Journal of Pesticide Science
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• v.15 no.2
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• pp.149-159
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• 2011

Bentazone is benzothiadiazole group herbicide, and used to foliage treatment. This herbicide have already been widely used for cereals and vegetables planting in worldwide. This experiment was conducted to establish a determination method for bentazone residue in crops using HPLC-UVD/MS. Bentazone residue was extracted with acetone (adjusted pH 1 with phosphoric acid) from representative samples of five raw products which comprised hulled rice, soybean, apple, green pepper, and Chinese cabbage. The extract was diluted with saline water, and dichloromethane partition was followed to recover bentazone from the aqueous phase. Florisil column chromatography was additionally employed for final clean up of the extract. The bentazone was quantitated by HPLC with UVD, using a YMC ODS AM 303 ($4.6{\times}250$ mm) column. The crops were fortified with bentazone at 3 levels per crop. Mean recovery ratio were ranged from 82.0% for a 0.2 mg/kg in apple to 97.9% for a 0.02 mg/kg in Chinese cabbage. The coefficients of variation were ranged from 0.5% for a 0.02 mg/kg in soybean to 9.7% for a 0.02 mg/kg in Chinese cabbage. Quantitative limit of bentazone was 0.02 mg/kg in representative five crop samples. A LC/MS with selected-ion monitoring was also provided to confirm the suspected residue. Therefore, this analytical method was reproducible and sensitive enough to determine the residue of bentazone in agricultural commodities.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.247-252
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• 2006

오염 퇴적물내 중금속의 방출과 이에 따른 생이용성(bioavalability)은 기존의 가역 평형관계로써 설명하기에 불충분한 것으로 알려져 있다. 최근 연구결과에 의하면 이러한 탈착 저항성을 설명하기 위한 비가역적 모델에 의해 퇴적물내 중금속의 탈착저항성 부분이 존재함이 밝혀졌다. 탈착저항성에 대해서는 아직 충분한 규명이 이루어지지 않았으나, 오염물질의 노화(aging)에 의해 일단 탈착저항성을 띠게 되면 생이용성(bioavailability)이 감소되는 것으로 알려져 있다. 본 연구에서는 노화(aging)가 연안 퇴적물 내 납과 카드뮴의 흡/탈착 특성에 미치는 영향을 알아보기 위해 연속 탈착실험과 biphasic 탈착모델을 적용함으로써 납과 카드뮴의 탈착저항성을 규명하고자 하였다. 그리고 연속 추출 실험을 통해서 노화(aging)에 따른 퇴적물 내 납과 카드뮴의 흡착 기작을 규명하고자 하였다. 연속탈착 실험 결과 시간이 경과함에 따라 탈착저항성부분의 크기가 증가하였으며, 연속추출 실험 결과 납의 경우 carbonate fraction에서 추출된 납이 가장 많았으며, 노화(aging) 따라 exchangeable fraction에서 추출된 납이 감소하는 반면 reducible, organic material, residual fraction에서 추출된 납의 양이 증가하였다. 카드뮴의 경우 가장 많은 양이 추출된 단계는 exchangeable fraction이였으며, organic material fraction에서는 카드뮴이 추출되지 않았다. 노화(aging) 따라 reducible fraction과 residual fraction에서의 추출량이 증가하는 경향을 보였으나 그 양은 매우 적은 것으로 나타났으며, 노화(aging)에 따른 exchangeable fraction과 carbonate fraction에서의 추출량은 큰 변화가 없었다. 대해서는 북한지역의 분포상황을 밝혔다.것을 알 수 있었으며, 크롬과 비소의 경우는 초기에 많이 용출되고, 구리의 경우는 꾸준히 용출되는 것을 알 수 있었다. 3년 된 통나무집이 8년 된 통나무집보다. 용출양이 더 컸으며, 이는 CCA성분이 초기에 많이 용출된다는 것을 의미한다. 억제 효과를 나타내었고 Hep3B에서는 부탄을 분획물 (1 mg/mL)에서 82%의 비교적 높은 성장억제효과를 나타내었다.as a "front" and "back". Thus, Germany′s private space may face a genuine public space and street, which is rare in the Korean housing. Although the layout of indoor space in the korean housing tends to be open, such an openness may be outstanding in living and dining spaces, kitchen and various accesses to rooms. In the case of Germany, such indoor spaces are usually closed to each other. Thus corridors act to separate these spaces. Such differences are analysed to be due to the different perceptions of interpersonal and socio-cultural attributes as intra-family and inter-neighbor relationships or communications. 알 수 있었다.도 질소와 인산처럼 토양지지대가 있는 경우가 낮은 함량을 유지하였다.pe from the daily life, to fantasize and daydre

• Applied Chemistry for Engineering
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• v.10 no.3
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• pp.374-381
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• 1999

Poly(vinyl alcohol) (PVA) membranes crosslinked with poly(styrene-maleic anhydride) (PSMAn) were prepared, and the pervaporation characteristics of the membranes were studied for the separation of water/ethanol mixtures. The prepared PVA membranes showed that the permeation rate and separation factors were increased with increasing of PSMAn contents in the feed of 92/8 wt. % ethanol/water composition. However, when the water content in the feed composition was increased highly, the overall permeation rate was increased in the order of 2%>1%>0.5% in spite of the increase of the crosslinking contents, and the separation factor was decreased due to the higher sorbed water contents and the consequent plasticization action of membrane. Also, with respect to operating temperature, the permeation rate of the membranes obeyed the Arrhenius type. Especially, in the case of 2% crosslinked membrane, it was shown based on the pervaporation characteristics that both the permeation rate and separation factor were increased with increasing operating temperature from $30^{\circ}C$( to $50^{\circ}C$. From these results, it can be known that the hydrophilic groups introduced in the membrane by PSMAn highly affected the transport of permeants.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.04a
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• pp.130-130
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• 1995

AM, SM 및 ASA는 수용액중에서 겉보기 1차반응에 따라 분해되었으며 보존온도가 높을수록 분해가 촉진되는 온도 의존성을 나타내었다. AM의 분해경로는 pH 1.22 및 pH 7.0 이상에서는 AM$\longrightarrow$ SM $\longrightarrow$ SA의 경로로 주로 분해되었으며 pH 2.01 - 6.08의 범위에서는 AM $\longrightarrow$ASA$\longrightarrow$SA의 경로로 분해되는 양상을 보였다. 또 pH가 분해에 미치는 영향을 pH-rate profile로 나타낸 결과 AM, SM 및 ASA의 최대안정 pH는 각각 4.0, 3.0, 2.0 부근이 있고 이 조건에서의 분해 반감기는 114, 168, 113 hr로 나타났다. 전체적으로 보면 pH 2.0 이하에서는 ASA가 AM 보다 약간 안정한 편이나 pH 2.0-8.0 사이에서는 AM의 분해속도가 ASA보다 현저히 낮았다. 또 AM은 pH 7.0 이상에서, SM은 pH 6.0 이상에서, ASA는 9.0 이상에서 특수염기촉매반응에 따라 분해가 이루어지는 것을 알 수 있었다. 이온강도($\mu$)의 영향으로는 pH 7.0에서 이온강도가 0.115에서 1.0으로 증가할수록 $\mu$$^{1}$2/에 대해 AM의 분해속도정수가 직선적으로 완만하게 감소되었다. 또 완충수용액 중 AM의 가수분해 억제효과를 검토하기 위해 시클로덱스트린류를 첨가하였을 때, $\beta$-시클로덱스트린과 히드록시프로필기-$\beta$-시클로덱스트린은 AM의 분해를 각각 1.6배 및 1.1배 촉진시켜 촉매적으로 작용하였으며 디메칠-$\beta$-시클로덱스트린은 약 3.2배 분해속도를 억제시켜 안정화제로 작용하였다.Zn^{2+}$, soybean trypsin inhibtor에 의해 25～50% 정도, serine proteinase inhibitor인 phenylmethylsulfonyl floride에 의해 80%정도 활성이 억제되는 특성이 있음을 규명하였다.면역환성 (immunoreactivity)이 나타났고 pyramidal cell layer (PCL)와 glia에 SOD-1이 강하게 염색되었다. APT 병용 투여로 상당수의 경련이 일어나지 않은 흰쥐는 해마의 DG에 FRA가 경미하게 염색되었고, PCL에 SOD-1도 경미하게 나타났으나, 경련이 나타난 쥐에서는 KA만을 투여한 흰쥐와 구별되지 않았다. 이상의 APT의 항산화 효과는 KA로 인한 뇌세포 변성 개선에 중요한 인자로 작용할 것으로 사료되나, 보다 명확한 APT의 기전을 검색하고 직접 임상에 응응하기 위하여는 보다 다양한 실험 조건이 보완되어야 찰 것으로 생각된다. 항우울약들의 항혈소판작용은 PKC-기질인 41-43 kD와 20 kD의 인산화를 억제함에 기인되는 것으로 사료된다.다. 것으로 사료된다.다.바와 같이 MCl에서 작은 Dv 값을 갖는데, 이것은 CdCl$_{4}$$^{2-}$ 착이온을 형성하거나 ZnCl$_{4}$$^{2-}$ , ZnCl$_{3}$$^{-}$같은 이온과 MgCl$^{+}$, MgCl$_{2}$같은 이온종을 형성하기 때문인것 같다. 한편 어떠한 용리액에서던지 NH$_{4}$$^{+}$의 경우 Dv값이 제일 작았다. 바. 본 연구의 목적중의 하나인 인체유해 중금속이온인 Hg(II), Cd(II)등이 NaCl같은 염화물이 함유된 시료용액에 공해이온으로 존재할 경우 흡착에 의한 제거가 가능하다. 한편 이같

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.4 no.4
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• pp.311-320
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• 2006

Removal characteristics of $H^{14}CO_3$ ion from IRN-150 mixed resin contaminated with $^{14}C$ radionuclide and a gasification behavior of $^{14}C$ radionuclide to $^{14}CO_2$ were investigated. The stripping solutions used for the removal of $^{14}C$ from spent resin were $NaNO_3,\;Na_3PO_4,\;NH_4H_2PO_4,\;H_3PO_4$. The influence of stripping solution concentration on the desorption characteristics of inactive $HCO_3$ ion into stripping solution from IRN-150 mixed resin and the gasification of this ion to $CO_2$ was analyzed. The gasification behavior to $CO_2$ by using NaOH, $HNO_3$, HCl was also compared to that of phosphate solution. Real spent resin stored in Wolsung nuclear power plant was used to evaluate the gasification characteristics of $^{14}C$ radionuclide to $^{14}CO_2$. Gamma radionuclides such as $^{137}Cs,\;^{60}Co$ in residual striping solutions after desorption experiment were analyzed.

• Applied Chemistry for Engineering
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• v.19 no.5
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• pp.574-581
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• 2008

The optimum regeneration conditions for the regeneration of three way spent catalysts (TWCs), which were taken from automobiles with different driving conditions, were investigated to evaluate the suitability as alternative catalysts for removing VOCs. The spent catalysts were washed with five different acids ($HNO_3$, $H_2SO_4$, $C_2H_2O_4$, $C_6H_8O_7$, and $H_3PO_4$) to remove contaminants and examine the optimum conditions for recovering the catalytic activity. The physicochemical properties of spent and its regenerated TWCs were evaluated by using nitrogen adsorption-desorption isotherms, XRD, and ICP. The relative atomic ratios of contaminants and platinum group metals (PGMs) of the spent TWCs were greatly dependent on the placed positions. The main contaminants formed were lubricant oil additives and metallic components. Also, the regeneration treatment increased the PGMs ratio, BET surface area, and average pore diameter of TWCs. The catalytic activity results indicated that the spent TWCs have the possibility for removing VOCs. Moreover, the employed acid treatments greatly enhanced the catalytic activity of the spent TWCs. Especially, nitric and oxalic acids provided the most improvement in the catalytic behavior. The catalytic activities of the regenerated TWCs were significantly influenced by the containing platinum ratios rather than the removal ratios of contaminants and the changes in the structural properties offered by the acid treatments.