• Korean Journal of Environmental Agriculture
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• v.42 no.1
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• pp.1-7
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• 2023

Super absorbent polymers (SAPs) are hydrophilic molecules that can absorb large amounts of water. This study was conducted to investigate the enhancement of the physicochemical properties of sand soil blended with three SAPs imbibed with 100, 150, and 200-fold water. Three treatments were applied, namely, 100SAP, 150SAP, and 200SAP. The three SAPs were blended at concentrations of 0% (control), 3%, 5%, 7%, and 10% with sand. The pH, electrical conductivity, and cation exchangeable capacity (CEC) of soil blended with the three SAPs were pH 6.35-6.46, 0.09-0.65 dS/m, and 1.42-1.92 cmol_c/kg, respectively, and their capillary porosity, total porosity, and saturated hydraulic conductivity were 21.0-29.3%, 39.2-48.7%, and 272-470 mm/hr. CEC, capillary porosity, total porosity, and saturated hydraulic conductivity of soil were positively correlated with the ratio of the SAPs (p<0.01). These results indicate that blending sand soil with SAPs increased CEC, capillary porosity, and saturated hydraulic conductivity, thus improving the nutrient-retention capacity, water-retention capacity, and permeability of the soil.

• Korean journal of applied entomology
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• v.24 no.1 s.62
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• pp.39-44
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• 1985

This study was undertaken to select a suitable Korean tissue paper for Baermann funnel method. Ten kinds of five manufacturers were evaluated as to nematode extraction efficiency in Baermann funnel. 'Crown Hankie'(Korea Special Paper Co., Ltd.) had suitable properties in nematode permeability and strength regardless of three soil types, loamy sand, sandy loam and clay loam. The number of nematodes extracted using 'Crown Hankie' 4 ply was 198, while that of 'Cottonwool Nematode Filter' was 227. Un-perfumed tissue papers showed higher nematode extraction efficiencies than perfumed tissue papers by 53 and 23% in 'Kleenex New Softness' and 'Monaliza Finely Soft Tissue', respectively. Among the nematode extraction efficiencies by temperatures, $15^{\circ},\;25^{\circ}\;and\;35^{\circ}C$, it was highest at $35^{\circ}C$. In experiment of evaluating nematode extraction using Baermann funnel at 12 hours interval to 92 hours, 35.3 and 40.3% of nematodes were extracted after 12 and 24 hours, respectively.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.5
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• pp.476-485
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• 2005

In this study, abiotic transformation of TNT reduction products via oxidative-coupling reaction was investigated using Mn oxide. In batch experiments, all the reduction products tested were completely transformed by birnessite, one of natural Mn oxides present in soil. Oxidative-coupling was the major transformation pathway, as confirmed by mass spectrometric analysis. Using observed pseudo-first-order rate constants with respect to birnessite loadings, surface area-normalized specific rate constants, $k_{surf}$, were determined. As expected, $k_{surf}$ of diaminonitrotoluenes (DATs) ($1.49{\sim}1.91\;L/m^2{\cdot}day$) are greater about 2 orders than that of dinitroaminotoluenes (DNTs) ($1.15{\times}10^{-2}{\sim}2.09{\times}10^{-2}\;L/m^2{\cdot}day$) due to the increased number of amine group. In addition, by comparing the value of $k_{surf}$ between DNTs or DATs, amino group on ortho position is likely to be more preferred for the oxidation by birnessite. Although cross-coupling of TNT in the presence of various mediator compounds was found not to be feasible, transformation of TNT by reduction using $Fe^0$ followed by oxidative coupling using Mn oxide was efficient, as evaluated by UV-visible spectrometry.

• Applied Biological Chemistry
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• v.13 no.2
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• pp.111-129
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• 1970

As a series of studies on the nucleic acids and their related substances 210 samples were collected from 76 places such as farm soil, compost of heap, nuruk and meju to obtain microbial strains which produce 5'-phosphodiesterase. From these samples total of 758 strains were isolated by the use of dilution pour plate method. For all isolated strains primary screening of the productivity of RNA depolymerase was performed and useful strains with regard to 5'-phosphodiesterase productivities were identified. For these useful strains optimum condition, the effect of various compounds on the activity of 5'-phosphodiesterase, and the optimum condition for enzyme reaction were discussed. The quantitative of 5'-mononucleotides produced by the action of 5'-phosphodiesterase was performed using anion-exchange column chromatography and their identified was done by paper chromatography, thinlayer chromatography, ultra violet spectrophotometry, and characteristic color reaction using carbazole and schiff's reagent. (1) Penicillium citreo-viride PO 2-11 and Streptomyces aureus SOA 4-21 from soil were identified as a potent 5'-phosphodiesterase producing strains. (2) Optimum culture conditions for Penicillium citreo-viride PO 2-11 strain isolated were found to be pH 5.0 and $30^{\circ}C$, and the optimum conditions for enzyme action of 5'-phosphodiesterase were pH 4.2 and $60^{\circ}C$. Best carbon source for the production of 5'-phosphodiesterase was found to be sucrose and ammonium nitrate for nitrogen source. Addition of 0.01% corn steep liquor or yeast extract exhibited 20% increase in the amount of 5'-phosphodiesterase production compared to the control. 5'-phosphodiesterase produced by this strain was activated by $Mg^{++},\;Ca^{++},\;Zn^{++},\;Mn^{++}$ and was inhibited by EDTA, citrate, $Cu^{++},\;CO^{++}$. 5'-phosphodiesterase produced 5'-mononucleotide from RNA at a rate of 65.81%, and among the 5'-mononucleotides accumulated 5'-GMP only was found to have flavorous and the strain was also found lack of 5'-AMP deaminase. Productivity of flavorous 5'-GMP was found to be 186.7mg per gram of RNA. (3) Optimum culture canditions for the isolated Streptomyces aureus SOA 4-21 strain were pH 7.0 and $28^{\circ}C$, and the optimum conditions for the action of 5'-phosphodiesterase were pH 7.3 and $50^{\circ}C$. The best carbon source for 5'-phosphodiesterase production was found to be glucose and that of nitrogen was asparagine. Addition of 0.01% yeast extract exhibited increased productivity of 5'-phosphodiesterase by 40% compared to the non-added control. 5'-phosphodiesterase produced by this strain was activated by $Ca^{++},\;Zn^{++},\;Mn^{++}$ and was inhibited by citrate, EDTA, $Cu^{++}$. It was also found that the strain produce 5'-AMP deaminase in addition to 5'-phosphodiesterase. For this reason although decomposition rate was 63.58% the accumulation of 5'-AMP, 5'-CMP, 5'-GMP and 5'-UMP occurred by the breakdown of RNA. In the course of these reaction 5'-AMP deaminase converted 60% of 5'-AMP thus produced into 5'-IMP and flavorous 5'-mono nucleotide production was significantly increased by this strain over the above mentioned one. Production rates were found to be 171.8mg per grain of RNA for 5'-IMP and 148.2mg per gram of RNA for 5'-GMP, respectively.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.4 no.3
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• pp.19-29
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• 2001

This study was carried out to examine the recovery of forest ecosystem at the burned areas of coniferous (Mt. Chosdae) and broad leaved forest (Samsinbong in Mt. Chiri) by investigating the changes of forest vegetation. The results obtained are summarized as follows; 1. In the Samsinbong, the total number of species appeared at the burned area were 5 species at tree layer, 11 species at sub-tree layer and 24 species at herb layer, and at the unburned area were 5 species at tree layer, 14 species at sub-tree layer, 18 species at shrub layer and 23 species at herb layer, respectively. In the Mt. Chosdae, the total number of species appeared at the burned area only showed to 83 species at herb layer, and at the unburned area were 7 species at tree layer, 13 species at sub-tree layer, 21 species at shrub layer and 46 species at herb layer, respectively. 2. In the soil chemical properties of the burned area of Samsinbong, pH was 5.8, and contents of Organic matter, Total nitrogen, Available $P_2O_5$, Exchangeable $K^+$, Exchange $Ca^{{+}{+}}$ and Exchange $Mg^{{+}{+}}$ were 7.42%, 0.73%, 28.5mg/kg, 1.3me/100g, 13.3me/100g and 2.2me/100g, respectively. But they showed a tendency to decrease by passing the time. In the soil chemical properties of the burned area of Mt. Chosdae, pH was 5.3, and contents of Organic matter, Total nitrogen, Available $P_2O_5$, Exchangeable $K^+$, Exchange $Ca^{{+}{+}}$ and Exchange $Mg^{{+}{+}}$ were 6.42%, 0.25%, 24.4mg/kg, 0.7me/100g, 3.7me/100g and 2.1me/100g, respectively, and they also showed a tendency to decrease by passing the time. 3. An the burned and unburned areas of Samsinbong, the total evolved amounts of soil respiration were $4,049.1mg/m^2/h$ and $9,950.0mg/m^2/h$, respectively. An the burned and unburned areas of Mt. Chosdae, the total evolved amounts of soil respiration were $4,392.4mg/m^2/h$ and $8,286.5mg/m^2/h$, respectively.

• Journal of Environmental Science International
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• v.25 no.11
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• pp.1541-1554
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• 2016

To understand the characteristics of vanadium leaching from soils formed by the weathering of basalts, paleo soil at Gosan, Jeju Island, Korea, and several present-day soils from neighboring areas were collected. Leaching experiments were carried out by two approaches: 1) batch experiments under various geochemical conditions (redox potential (Eh) and pH) and 2) continuous leaching experiments under conditions similar to those of natural environments. From the batch experiments, leached vanadium concentrations were highest under alkaline (NaOH) conditions, with a maximum value of $2,870{\mu}g/L$, and were meaningful (maximum value, $114{\mu}g/L$) under oxidizing ($H_2O_2$) conditions, whereas concentrations under other conditions (acidic-HCl, $neutral-NaHCO_3$, and $reducing-Na_2S_2O_3$) were negligible. This indicated that the geochemical conditions, in which soil-water reactions occurred to form groundwater with high vanadium concentrations, were under alkaline-oxidizing conditions. From the continuous leaching experiments, the pH and leached vanadium concentrations of the solution were in the ranges of 5.45~5.58 and $6{\sim}9{\mu}g/L$, respectively, under $CO_2$ supersaturation conditions for the first 15 days, whereas values under $O_2$ aeration conditions after the next 15 days increased to 8.48~8.62 and $9.7{\sim}12.2{\mu}g/L$, respectively. Vanadium concentrations from the latter continuous leaching experiments were similar to the average concentration of groundwater in Jeju Island ($11.2{\mu}g/L$). Furthermore leached vanadium concentrations in continuous leaching experiments were highly correlated with pH and Al, Cr, Fe, Mn and Zn concentrations. The results of this study showed that 1) alkaline-oxidizing conditions of water-rock (soil) interactions were essential to form vanadium-rich groundwater and 2) volcanic soils can be a potential source of vanadium in Jeju Island groundwater.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.5
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• pp.418-428
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• 2007

Physical and chemical properties of the aggregate by-products including sludge and crushed dust samples collected from the 21 private companies throughout the country were analyzed to evaluate possible usage of the by-products as artificial soil materials for plantation. The pH of the materials ranged from 8.0 to 11.0. The organic matter content was $2.85g\;kg^{-1}$, and the total nitrogen content and available phosphate content were low as 0.7 percents and $12.98mg\;kg^{-1}$, respectively. Exchangeable $Ca^{2+}$, $Mg^{2+}$, $K^+$, and $Na^+$ were 2.29, 0.47, 0.02 and $0.05cmol\;kg^{-1}$, respectively. Heavy metal contents were lower than the limits regulated by environmental law of Korea. Textural analysis showed that most of the materials were silt loam with low water holding capacity ranged from 0.67 to 7.41 percents, and with low hydraulic conductivity ranged from 0.4 to $2.8m\;s^{-1}$. Mineralogical analysis showed that the aggregate by product materials were mostly composed of silicate, alumina and ferric oxides except calcium oxide dominant materials derived from limestones. The primary minerals were quartz, feldspars and dolomites derived from granite and granitic gneiss materials. Some samples derived from limestone material showed calcite and graphite together with the above minerals. According to the result, it can be concluded that the materials could be used as the artificial soil material for plantation after proper improvement of the physico-chemical properties and fertility.

• The Korean Journal of Pesticide Science
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• v.10 no.2
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• pp.131-137
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• 2006

This experiment was conducted to select prominent microorganisms with a good insecticidal activity among the ten species, which isolated from soil at the near of Chung-buk, Chung-nam, and Gang-won provinces and made protein crystal endotoxin. As a result, GB-413 strain was finally selected, which showed the high insecticidal activity against susceptible diamondback moth (Plutella xylostella), beet army worm (Spodoptera exigua) and tobacco cutworm (Spodoptera litura) as well as resistant diamondback moth strains. By modifying the cultivation process f.g. lowing the glucose concentration at early cultivation stage and adding the carbon after inducing the spores, the percentage of making spore as well as the number of active spore were increased and the time for cultivation and spore forming was reduced without a reduction of insecticidal activity. These results were not only applied successfully for the optimized cultivation process for a fermentation tank containing five tons capacity, but also improved the possibility of mass cultivation for commercial production.

• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.4
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• pp.296-304
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• 2018

The objective of this study was to analyze the impact of climate change on rice yield and quality. Experiments were conducted using SPAR(Soil-Plant-Atmosphere-Research) chambers, which was designed to create virtual future climate conditions, in the National Institute of Crop Science, Jeonju, Korea, in 2016. In the future climate conditions($+2.8^{\circ}C$ temp, 580 ppm $CO_2$) of year 2051~2060 according to RCP 8.5 scenario, elevated temperature and $CO_2$ accelerated the heading date by about five days than the present climate conditions, resulted in a high temperature environment during grain filling stage. Rice yield decreased sharply in the future climate conditions due to the high temperature induced poor ripening. And the spikelet numbers, ripening ratio, and 1000-grain weight of brown rice were significantly decreased compared to control. The rice grain quality was also decreased sharply, especially due to the increased immature grains. In the future climate conditions, expression of starch biosynthesis-related genes such as granule-bound starch synthase(GBSSI, GBSSII, SSIIa, SSIIb, SSIIIa), starch branching enzyme(BEIIb) and ADP-glucose pyrophosphorylase(AGPS1, AGPS2, AGPL2) were repressed in developing seeds, whereas starch degradation related genes such as ${\alpha}-amylase$(Amy1C, Amy3D, Amy3E) were induced. These results suggest that the reduction in yield and quality of rice in the future climate conditions is likely caused mainly by the poor grain filling by high temperature. Therefore, it is suggested to develop tolerant cultivars to high temperature during grain filling period and a new cropping system in order to ensure a high quality of rice in the future climate conditions.

• Journal of the Korean Society of Groundwater Environment
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• v.5 no.3
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• pp.162-170
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• 1998

Geochemical characteristics of groundwater in Goryeong area, based on chemical analyses of 34 water samples and mineralogical study of rocks, differ among Nagdong, Hasandong and Jinju formations and Goryeong granite in relation to mineralogical compositions of the rocks. Concentrations of most solutes are higher in groundwater of the sedimentary formations than in that of granite. Ca$\^$2＋/ in the sedimentary groundwaters results mainly from reaction of CO$_2$-charged water with calcite and weathered plagioclase. Average groundwater in the Jinju formation is oversaturated with respect to calcite. Major types of groundwaters are hard Ca(HCO$_3$)$_2$ and CaSO$_4$with hardness of 155 mg/1 for Nagdong formation, 150 mg/1 for Hasandong formation and 140 mg/1 for Jinju formation whereas it is soft Ca(HCO$_3$)$_2$with hardness of 90 mg/1 for Goryeong granite. Ca(HCO$_3$)$_2$type resole from dissolution of calcite and plagiodase while CaSO$_4$type results from dissolution of pyrite and partly from domestic pollutants. CaSO$_4$type may indicate that the sedimentary groundwaters are more evolved geochemically than the granitic groundwater, but it is not obvious because the type might be affected by the dissolution of pyrite and domestic pollutions. Prite is expected to occur as a stable sulfide in the gray∼dark gray arkosic sandstones formed under reducing environment.