• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.5
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• pp.505-513
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• 1996

This study was conducted to investigate the variation of chemical components in stagnant water under different mulching amount of barley straw after combine harvesting and the effect of stagnent water on the germinatidn and seedling elongation at early growth stage in rice. pH was lower in barley straw mulching than non-mulching and decreased with increasing of mulched barley straw but was not different among treatments in stagnant water at 15 days after flooding. Dissolved oxygen decreased with the increasing of mulched barley straw and increased with the passing of time, while saline content increased with the increasing of mulched barley straw, showing significant difference among treatments, was peaked at 15 days after flooding and thereafter, decreased. NH4-N was higher 5 days after flooding with thicker barley straw mulching but was not different at 10 days. N $O_3$-N increased up to 10 to 15 days after flooding and increased with thicker barley straw mulching. Water soluble phosphorus and cation content ( $K^{+}$, $Ca^{2+}$, $Mg^{2+}$)were higher in thicker barley straw mulching and peaked at 10 and 15 days after flooding. Germination rate was decreased by thicker straw mulching and was high in order of medium late, medium and early maturing rice variety. Keumobyeo, Gancheokbyeo, Ilpumbyeo, Dongjinbyeo and Gyehwabyeo showed higher germination rate. Seedling elongation at early growth stage was poorer with increasing of barley. straw mulching. Ilpumbyeo had good seedling elongation in one time amount of barley straw mulching and Shinunbongbyeo, Unjangbyeo, Nonganbyeo and Dongjinbyeo had poorer, in two times.mes.

• Journal of Applied Biological Chemistry
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• v.65 no.4
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• pp.253-259
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• 2022

The aim of this study was to investigate the correlation between growth characteristics and ginsenoside contents of 4-year-old wild-simulated ginseng cultivated in different regions. Most of the soil properties except for available phosphate showed significantly higher in Pyeongchang than in other cultivation sites. The growth characteristics except for root length and number of rootlets showed significantly higher in Pyeongchang than in other cultivation sites. In the case of 8 ginsenoside contents, the content of F2-AS was significantly higher in Muju than in other cultivation sites and the content of F1 in Yeongju was significantly high. In Yeongwol, the contents of Rb1 and Re-p were significantly high and the content of Ro in Pyeongchang showed significantly higher than in other cultivation sites. Root length and soil pH did not show a significant correlation with any soil properties and growth characteristics of wild-simulated ginseng, respectively. Most of the growth characteristics showed significantly positive correlations with electrical conductivity, organic matter content, total nitrogen content, exchangeable cations (K⁺, Ca²⁺, Mg²⁺), and cation exchange capacity. Rb1 and Re-p showed significantly negative correlations with most of the growth characteristics of wild-simulated ginseng except for the number of rootlets. Ro showed a significantly positive correlation with stem length, number of leaflets per stem, leaflet length, leaflet width, and root diameter. The results of this study probably will help to provide useful information on the establish a quality standard by investigate correlation analysis between growth characteristics and ginsenoside content of 4-year-old wild-simulated ginseng.

• Economic and Environmental Geology
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• v.56 no.3
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• pp.311-330
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• 2023

Development of Carbon Capture and Storage (CCS) technique is becoming increasingly important as a method to mitigate the strengthening effects of global warming, generated from the unprecedented increase in released anthropogenic CO₂. In the recent years, the characteristics of basaltic rocks (i.e., large volume, high reactivity and surplus of cation components) have been recognized to be potentially favorable in facilitation of CCS; based on this, research on utilization of basaltic formations for underground CO₂ storage is currently ongoing in various fields. This study investigated the feasibility of underground storage of CO₂ in basalt, based on the examination of the CO₂ storage mechanisms in subsurface, assessment of basalt characteristics, and review of the global research on basaltic CO₂ storage. The global research examined were classified into experimental/modeling/field demonstration, based on the methods utilized. Experimental conditions used in research demonstrated temperatures ranging from 20 to 250 ℃, pressure ranging from 0.1 to 30 MPa, and the rock-fluid reaction time ranging from several hours to four years. Modeling research on basalt involved construction of models similar to the potential storage sites, with examination of changes in fluid dynamics and geochemical factors before and after CO₂-fluid injection. The investigation demonstrated that basalt has large potential for CO₂ storage, along with capacity for rapid mineralization reactions; these factors lessens the environmental constraints (i.e., temperature, pressure, and geological structures) generally required for CO₂ storage. The success of major field demonstration projects, the CarbFix project and the Wallula project, indicate that basalt is promising geological formation to facilitate CCS. However, usage of basalt as storage formation requires additional conditions which must be carefully considered - mineralization mechanism can vary significantly depending on factors such as the basalt composition and injection zone properties: for instance, precipitation of carbonate and silicate minerals can reduce the injectivity into the formation. In addition, there is a risk of polluting the subsurface environment due to the combination of pressure increase and induced rock-CO₂-fluid reactions upon injection. As dissolution of CO₂ into fluids is required prior to injection, monitoring techniques different from conventional methods are needed. Hence, in order to facilitate efficient and stable underground storage of CO₂ in basalt, it is necessary to select a suitable storage formation, accumulate various database of the field, and conduct systematic research utilizing experiments/modeling/field studies to develop comprehensive understanding of the potential storage site.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1B
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• pp.51-60
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• 2006

Water quality improvement in mattress/filter system using porous material like slag from industrial activity and zeolite that has been studied for environment improvement and pollution abatement is very useful in polluted stagnant stream channel. Slag is consisted of CaO, $SiO_2$, $Al_2O_3$ and $Fe_2O_3$. Slag with large specific surface area of porosity has been used such as sludge settling and adsorptive materials. Because slag is porous, it can be used for purification filter. As slag is used as filled materials of mattress/filter system and the system has good advantages for the waste water treatment, water recycling, and the improvement of water quality at the same time and so on. Because zeolite has much advantage of cation exchange, adsorption, catalyst and dehydration characteristics, It is used for environment improvement of livestock farms, treatment of artificial sewage and waste water, improvement of drinking water quality, radioactive waste disposal and radioactive material pollution control. In this study, according to verifying effects of water quality improvement of fill materials by porosity that 38.6%, 45.8% and 49.8% respectively in the stagnant stream channel, water quality monitoring of inflow and outflow was conducted on pH, DO, BOD, COD, SS, T-N and T-P. Mattress/filter system was able to accelerate water quality improvement by biofilter as waste water flows through gap of mattress/filter fill materials and by contact catalysis, absorption, catabolism by biofilm. Mattress/filter system used slag and zeolite forms biofilm easily and accelerates adsorption of organic matter. As a result, mattress/filter system increases water self-purification and accelerates water quality improvement available for stream water clean-up.

• Economic and Environmental Geology
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• v.56 no.6
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• pp.729-744
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• 2023

The value of lithium has significantly increased due to the rising demand for electric cars and batteries. Lithium is primarily found in pegmatites, hydrothermally altered tuffaceous clays, and continental brines. Globally, groundwater-fed salt lakes and oil field brines are attracting attention as major sources of lithium in continental brines, accounting for about 70% of global lithium production. Recently, deep groundwater, especially geothermal water, is also studied for a potential source of lithium. Lithium concentrations in deep groundwater can increase through substantial water-rock reaction and mixing with brines. For the exploration of lithim in deep groundwater, it is important to understand its origin and behavior. Therefore, based on a nationwide preliminary study on the hydrogeochemical characteristics and evolution of thermal groundwater in South Korea, this study aims to investigate the distribution of lithium in the deep groundwater environment and understand the geochemical factors that affect its concentration. A total of 555 thermal groundwater samples were classified into five hydrochemical types showing distinct hydrogeochemical evolution. To investigate the enrichment mechanism, samples (n = 56) with lithium concentrations exceeding the 90th percentile (0.94 mg/L) were studied in detail. Lithium concentrations varied depending upon the type, with Na(Ca)-Cl type being the highest, followed by Ca(Na)-SO₄ type and low-pH Ca(Na)-HCO₃ type. In the Ca(Na)-Cl type, lithium enrichment is due to reverse cation exchange due to seawater intrusion. The enrichment of dissolved lithium in the Ca(Na)-SO₄ type groundwater occurring in Cretaceous volcanic sedimentary basins is related to the occurrence of hydrothermally altered clay minerals and volcanic activities, while enriched lithium in the low-pH Ca(Na)-HCO₃ type groundwater is due to enhanced weathering of basement rocks by ascending deep CO₂. This reconnaissance geochemical study provides valuable insights into hydrogeochemical evolution and economic lithium exploration in deep geologic environments.

• Journal of Korean Society of Forest Science
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• v.112 no.4
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• pp.502-514
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• 2023

This study was conducted to understand the long-term changes in soil physiochemical properties and seedling growth in Larix kaempferi (larch) stands planted in clear-cut larch and Pinus rigida (pine) forest soils over an 11-year period after reforestation. Two-year-old bare-root larch seedlings were planted in 2009-2010 at a density of 3,000 seedlings ha^-1 in clear-cut areas that harvested larch (Chuncheon and Gimcheon) and pine (Wonju and Gapyeong) stands. We analyzed the physiochemical properties of the mineral soils sampled at 0-20 cm soil depths in the planting year, and the 3^rd, 7^thand 11^th years after planting, and we measured seedling height and root collar diameter in those years. We found significant differences in soil silt and clay content, total carbon and nitrogen concentration, available phosphorus, and cation exchangeable capacity between the two stands; however, seedling growth did not differ. The mineral soil was more fertile in Gimcheon than in the other plantations, while early seedling growth was greatest in Gapyeong. The seedling height and diameter at 11 years after planting were largest in Wonju (1,028 tree ha^-1) and Chuncheon (1,359 tree ha^-1) due to decreases in stand density after tending the young trees. The soil properties in all plantations were similar 11 years after larch planting. In particular, the high sand content and high available phosphorus levels (caused by soil disturbance during clear-cutting and planting) showed marked decreases, potentially due to soil organic matter input and nutrient uptake, respectively. Thus, early reforestation after clear-cutting could limit nutrient leaching and contribute to soil stabilization. These results provide useful information for nutrient management of larch plantations.

• Korean Journal of Mineralogy and Petrology
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• v.36 no.4
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• pp.313-321
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• 2023

Numerous studies have investigated the adsorptive sequestration of radioactive cesium in the natural environment. Among these studies, adsorption onto minerals and high-temperature treatment stand out as highly effective, as demonstrated by the use of zeolite. In this study, cesium was ion-exchanged with birnessite and subsequently underwent high-temperature treatment up to 1100℃ to investigate both mineral phase transformation and the leaching characteristics of cesium. Birnessite has a layered structure consisting of MnO₆ octahedrons that share edges, demonstrating excellent cation adsorption capacity. The high-temperature treatment of cesium-ion-exchanged birnessite resulted in changes in the mineral phase, progressing from cryptomelane, bixbyite, birnessite to hausmannite as the temperature increased. This differs from the phase transformation observed in the tunneled manganese oxide mineral todorokite ion-exchanged with cesium, which shows phase transformation only to birnessite and hausmannite. The leaching of cesium from cesium-ion-exchanged birnessite was estimated by varying the reaction time using both distilled water and a 1 M NaCl solution. The leaching quantity changed according to the treatment temperature, reaction time, and type of reaction solution. Specifically, the cesium leaching was higher in the sample reacted with 1 M NaCl compared to the sample with distilled water and also increased with longer reaction time. For the samples reacted with distilled water, the cesium leaching initially increased and then decreased, while in the NaCl solution, the leaching decreased, increased again, and finally nearly stopped like the sample in the distilled water for the sample treated at 1100℃. These changes in leaching are closely associated with the mineral phases formed at different temperatures. The phase transformation to cryptomelane and birnessite enhanced cesium leaching, whereas bixbyite and hausmannite hindered leaching. Notably, hausmannite, the most stable phase occurring at the highest temperature, demonstrated the greatest ability to inhibit cesium leaching. This results strongly suggest that high-temperature treatment of cesium-ion-exchanged birnessite effectively immobilizes and sequesters cesium.

• Food Science and Preservation
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• v.30 no.2
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• pp.347-357
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• 2023

The succulent plant Aeonium sedifolium leaves contain several compounds that are of interest for their cosmetic uses on the skin. This study measured the inhibitory effects of enzyme production and antioxidant, astringent effects and skin wrinkles using Aeonium sedifolium leaves (ASL). The total phenolics compounds (TPC) content of ASL under optimal extraction conditions was 34.49 mg/g for hot water extract (ASLW) and 61.64 mg/g for 50% ethanol extract (ASLE). The ASLW and ASLE extracts were freeze-dried, powdered, and used as solids. TPC content, 2,2-diphenyl-1-picrylhydrazy (DPPH) radical scavenging activity, and 2,2'-azinobis (3-ethylben-zothiazoline 6-sulfonate) (ABTS) radical inhibition of the ASL phenolics were tested. The DPPH radical scavenging activities of ASLW and ASLE were tested at a TPC of 100 ㎍/mL. ABTS radical inhibition showed antioxidant activity of 100.00% in ASLW and ASLE, and the antioxidant protection factor of ASLW and ASLE was 1.07 and 1.22, respectively. The thiobarbituric acid-reactive substance (TBARS) inhibitory activity of ASLW and ASLE was 77.00%. The elastase inhibitory activity of ASLE was 69.03%, and collagenase inhibition activity for ASLW and ASLE was 29.82% and 54.76%, respectively. The astringent effect of ASLE was 89.82% at a TPC of 200 ㎍/mL. Thus, we concluded that ASL has the potential as a functional cosmetic ingredient with anti-aging effects on the skin.

• Journal of Forest and Environmental Science
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• v.3 no.1
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• pp.1-9
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• 1983

The purpose of this study was to elucidate the ecophysiological habitat of natural Sorbus commixta forest at Mt. Seorak. The results obtained were as follows: 1. The Sorbus commixta trees mainly distributed from 900m to 1,500m altitude. In there, the warm index(WI) was about 42$3.2{\times}10^3$ to $9.2{\times}10^3$, cation exchange capacity(CEC) was 13.7 to 19.5mg/100g, N content 0.21 to 0.39%, $P_2O_5$ content was 22.6 to 38.7ppm, and pH value was 5.6 to 5.8 respectively. 4. The upper crown trees in Sorbus commixta communities were Abies nephrolepis, Taxus cuspidata, Betula platyphylla var. japonica, Quercus${\times}$grosseserrata, Acer mono, Prunus sargentii, Carpinus cordata, Tilia amurensis, and the under crown trees were Rhododendron brachycarpum, Acer pseudo-sieboldianum, Thuja olientalis, Corylus heterohpylla, Philadelphus schrenckii, Rhododendron schlippenbachii, Rhododendron mucronulatum, and Magnolia sieboldii. 5. The stand densities were 1,156 trees/ha at 1,160m and 3,600 trees/ha at 1,300m respectively. The coverages by the DBH basal area were 0.37 at 1,160m and 0.31 at 1,300m respectively, and the vegetation coverages by the crown projection area were 2.04 at 1,160m and 1.61 at 1,300m respectively. 6. The light extinction coefficient(k) in Beer-Lambert's law, showed the distance, F(z), from top canopy to aboveground, was 0.17. 7. The water relations parameters of Sorbus commixta shoot were obtained by the pressure chamber technique. The osmotic pressure, ${\pi}_o$, at maximum turgor was -16.2 bar, and VAT pressure was 14.5bar. The osmotic pressure, ${\pi}_p$, at incipient plasmolysis was -19.4bar. The relative water contents at incipient plasmolysis were 83.1% ($v_p/v_o$) and 87.1%($v_p/w_s$;$w_s$, total water at maximum turgor). 8. The bulk modulus of elasticity(E) of shoot was about 69.6. The total symplasmic water to total water in shoot was 67.7%, and the apoplastic water to total water was 32.3%.

• Applied Biological Chemistry
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• v.10
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• pp.1-13
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• 1968

Phytin is a salt(mainly calcium and magnesium) of phytic acid and its purity and molecular formula can be determined by assaying the contents of phosporus, calcium and magnesium in phytin. In order to devise a new method for the quantitative analysis of the three elements in phytin, the chelatometric method was developed as follows: 1) As the pretreatment for phytin analysis, it was ashfied st $550{\sim}600^{\circ}C$ in the presence of concentrated nitric acid. This dry process is more accurate than the wet process. 2) Phosphorus, calcium and megnesium were analyzed by the conventional and the new method described here, for the phytin sample decomposed by the dry process. The ashfied phytin solution in hydrochloric acid was partitioned into cation and anion fractions by means of a ration exchange resin. A portion of the ration fraction was adjusted to pH 7.0, followed by readjustment to pH 10 and titrated with standard EDTA solution using the BT [Eriochrome black T] indicator to obtain the combined value of calcium and magnesium. Another portion of the ration fraction was made to pH 7.0, and a small volume of standard EDTA solution was added to it. pH was adjusted to $12{\sim}13$ with 8 N KOH and it was titrate by a standard EDTA solution in the presence of N-N[2-Hydroxy-1-(2-hydroxy-4-sulfo-1-naphytate)-3-naphthoic acid] diluted powder indicator in order to obtain the calcium content. Magnesium content was calculated from the difference between the two values. From the anion fraction the magnesium ammonium phosphate precipitate was obtained. The precipitate was dissolved in hydrochloric acid, and a standard EDTA solution was added to it. The solution was adjusted to pH 7.0 and then readjusted to pH 10.0 by a buffer solution and titrated with a standard magnesium sulfate solution in the presence of BT indicator to obtain the phosphorus content. The analytical data for phosphorus, calcium and magnesium were 98.9%, 97.1% and 99.1% respectively, in reference to the theoretical values for the formula $C_6H_6O_{24}P_6Mg_4CaNa_2{\cdot}5H_2O$. Statical analysis indicated a good coincidence of the theoretical and experimental values. On the other hand, the observed values for the three elements by the conventional method were 92.4%, 86.8% and 93.8%, respectively, revealing a remarkable difference from the theoretical. 3) When sodium phytate was admixed with starch and subjected to the analysis of phosphorus, calcium and magnesium by the chelatometric method, their recovery was almost 100% 4) In order to confirm the accuracy of this method, phytic acid was reacted with calcium chloride and magnesium chloride in the molar ratio of phytic: calcium chloride: magnesium chloride=1 : 5 : 20 to obtain sodium phytate containing one calcium atom and four magnesium atoms per molecule of sodium phytate. The analytical data for phosporus, calcium and magnesium were coincident with those as determine d by the aforementioned method. The new method employing the dry process, ion exchange resin and chelatometric assay of phosphorus, calcium and magnesium is considered accurate and rapid for the determination of phytin.