• Korean Journal of Soil Science and Fertilizer
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• v.14 no.1
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• pp.37-43
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• 1981

This pot experiment was conducted to find out the optimal fertilization ratio of the cations(K: Ca: Mg) in various soil conditions. Soil samples were collected from uncultivated mountains and hills where development for grass lands is under consideration. The optimum ratios were computed by the Homes systematic variation technique. The results were summarized as follows : 1. The optimum fertilization ratios of the cations (K : Ca : Mg) for the high yields of grass-clover mixed sward at various areas were obtained (Table 4) 2. The relatively high optimum fertilization ratios of K in Daegu and Taegwalryong, Ca in Unbong, and Mg in Cheju district gave the high yields of clover in mixed sward. They were positively related to the low contents of the above cations in the soils or the relatively low content ratio comparing with other cations. 3. The yields of clover in mixed sward were seriously affected by the changes in both the fertilization ratio and total concentration of cations comparing to those of the grass yields. As a consequence, total yields, quality, and botanical composition of the mixed sward were also affected. 4. The antagonis among the cations K, Ca, and Mg was known from the point of mineral contents of grass and clover. 5. The equivalent ratio K/(Ca+Mg) or grass was greatly increased by the range of 2.4 and 3.3 in the K-group treatment, which was higher than the critical level 2.2 of grass tetany, otherwise that. of clover by the range of 0.9 and 1.2. Therfore, it may be concluded that if the botanical composition of grass/legume sward is optimum, the incidence of grass tetany can be eliminated.

• Journal of Gifted/Talented Education
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• v.13 no.1
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• pp.65-80
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• 2003

The purpose of this study was to investigate the Asynchronous development of young gifted children by parents' perception. Total 3 groups of 145 subjects from age 30 months to 6 years 10 months old young gifted children's parents participated. The major findings were as follows: (1) The mean developmental characteristics was at a high average level. The developmental subscales tended to be high. The level of verbal understanding/expression tended to be high. It reared as followed; intellectual capacity, emotional maturity, visual-motor coordination, morality, self-behavior control, emotion control, physical development, social development, peer relationship, leadership ability. (2) There were significant differences between intellectual capacity, verbal understanding /expression and physical, social development, self-behavior control, emotion control. There were significant differences between physical development, self-behavior control and emotion control as children got lower. There were significant differences between verbal understanding/expression and visual-motor coordination as children got older. There were significant differences between social development, peer relationship and self-behavior control, emotion control as children got older. Also, there were significant differences between leadership ability and self-behavior control, emotion control as children got older. There were significant differences between morality and self-behavior control as children got older. These findings suggested that young gifted children were in the special needs because of the developmental differences.

• Economic and Environmental Geology
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• v.28 no.4
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• pp.351-367
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• 1995

The elemental geochemistry and oxygen isotopes of illite/smectite (I/S) have been studied in relationship to the mineralogical trend in the Reindeer D-27 well, Beaufort-Mackenzie Basin. The increase in concentrations of $K_2O$, Rb and rare earth elements (REE), the decrease in concentrations of tetrahedral elements such as Mg, Ti, Sc, Zn and Zr, and the increase in concentrations of tetrahedral elements such as Be and V can be related to I/S compositions that vary systematically with depth. Layer formulae of S- and I-layers are estimated as $[Al_{1.57}Fe_{.19}Mg_{.31}Ti_{.07}][Si_{3.84}Al_{.16}]O_{10}(OH)_2$ and $[Al_{1.84}Mg_{.16}][Si_{3.33}Al_{.67}]O_{10}(OH)_2$, respectively. The mobilization of REE appears to occur during illitization. The increase in concentrations of REE, especially La and Ce, with depth is probably linked to incorporation of ions with high valency (e.g. $V^{5+}$) in tetrahedral sites. The excess valency due to V is partly counter-balanced by ions with low valency (e.g. $Be^{2+}$) and, in turn, the local valency deficiency caused by $Be^{2+}$ could be compensated by high-charge interlayer cations such as REE (＋3). ${\delta}^{18}O$ values of I/S range from 2.91 to 15.72‰ (SMOW), and increase with depth, contrasting to trends observed in the Gulf Coast and elsewhere. The increase in ${\delta}^{18}O$ of I/S results from the rapid increase in ${\delta}^{18}O$ of pore water that overcomes the decrease in temperature-dependent fractionation values with increasing burial depth (${\delta}^{18}O_{pore\;water}>-d{\Delta}/_{I/S-water};\;d{\delta}^{18}O_{I/S}>0$). Calculated ${\delta}^{18}O$ values of pore water in equilibrium with I/S suggest that the original water was probably meteoric water. The stratification of pore water is postulated from the presence of an isotopically light interval, about 450m thick. The depth range of the isotopically light zone overlaps, but does not coincide with the interval of lowered I-content and $K_2O$ concentrations, suggesting that oxygens may have been exchanged independently of mineralogical and geochemical reactions.

• Korean Journal of Soil Science and Fertilizer
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• v.41 no.1
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• pp.26-33
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• 2008

Soil nutrient status in an organic apple farm was evaluated in relation to a conventional farm to better understand the effects of organic farming system on soil fertility. Soil organic matter, total and mineral N, available P, exchangeable cations, and available micronutrients were monitored at depth of 5-20 cm from May to October in 2006. Average soil organic matter content was 63.3 and $31.0g\;kg^{-1}$ in organic and conventional farm, respectively. Total N content was 3.3 and $1.7g\;kg^{-1}$ in average for organic and conventional farm, respectively. Ammonium and nitrate N in organic farming were maintained at relatively stable levels, but in the conventional farm the levels were very high in early season due to the chemical fertilizer application. In the organic apple farm, available P content in May was lower than that found in the conventional farm, but during the growing season available P content was continuously increased and in August the content was more than $1000mg\;P_2O_5\;kg^{-1}$. The organic farm maintained relatively greater exchangeable K, Ca, and Mg levels than the conventional farm. Available Cu, Fe, and Mn contents in the conventional farm were relatively greater than those found in the organic farm. However, available Zn extracted in 0.1 M HCl was much greater in the organic farm. Nutrient levels above crop needs were observed in both conventional and organic apple farm suggesting a more appropriate management of soil nutrients in organic farming to secure its fundamental functions for the sustainable agriculture.

• Journal of the Korean Chemical Society
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• v.66 no.2
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• pp.78-85
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• 2022

Natural white clay was treated with 6 M of H₂SO₄ and heated at 80℃ for 6 h under mechanical stirring and the resulting acid active clay was used as an adsorbent for the removal of Cs⁺ in water. The physicochemical changes of natural white clay and acid active clay were observed by X-ray Fluorescence Spectrometry (XRF), BET Surface Area Analyser and Energy Dispersive X-line Spectrometer (EDX). While activating natural white clay with acid, the part of Al₂O₃, CaO, MgO, SO₃ and Fe₂O₃ was dissolved firstly from the crystal lattice, which bring about the increase in the specific surface area and the pore volume as well as active sites. The specific surface area and the pore volume of acid active clay were roughly twice as high compared with natural white clay. The adsorption of Cs⁺ on acid active clay was increased rapidly within 1 min and reached equilibrium at 60 min. At 25 mg L^- of Cs⁺ concentration, 96.88% of adsorption capacity was accomplished by acid active clay. The adsorption data of Cs⁺ were fitted to the adsorption isotherm and kinetic models. It was found that Langmuir isotherm was described well to the adsorption behavior of Cs⁺ on acid active clay rather than Freundlich isotherm. For adsorption Cs⁺ on acid active clay, the Langmuir isotherm coefficients, Q, was found to be 10.52 mg g^-1. In acid active clay/water system, the pseudo-second-order kinetic model was more suitable for adsorption of Cs⁺ than the pseudo-first-order kinetic model owing to the higher correlation coefficient R² and the more proximity value of the experimental value q_e,exp and the calculated value q_e,cal. The overall results of study showed that acid active clay could be used as an efficient adsorbent for the removal of Cs⁺ from water.

• The Journal of Engineering Geology
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• v.2 no.2
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• pp.173-200
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• 1992

The quality of groundwater in the central part of Taegu City is influenced by upstreams of Sin-stream and Beomeo-stream because the stream waters are main source of the groundwater, and chemical composition of the upstream waters has close relationship with andesite and monzonite in the igneous rock terrain. The pH of upstreams are weak acid ~ neutral in the igneous rock area and weak alkaline in the sedimentary rock area. Contents of $Ca^{2+}$ and $Mg^{2+}$ in the streams are apparently high, and $Na^{+}$ content is only slightly high in the sedimentary rock area. But $K^{+}$ content is lower in the Panyaweol formation area than in the monzonite area. The contents of heavy metals and $N0_3^{-}$ are also higher in the sedimentary rock area of residential sections and industrial complexes than those in the igneous rock area. The groundwater is contaminated in comparison to the upstream water of the igneous rock areas, and there are some differences in pollution level between the Panyaweol formation area of residential sections and the Haman formation area of industrial complexes. K, Na, Ca, Mg, Cl, $SO_4$ and $NO_3$ contents in the Haman formation area are relatively higher than those in the Panyaweol formation area. But pH is nearly equal in the two areas. The content of heavy metal ions is still lower than the drinking water standard of Korea and only slightly differs in the two sedimentary rock areas. But the groundwater in the Haman formation area is considerably contaminated by Kongdanstream and Dalseo-stream.

• 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.

• Journal of Applied Biological Chemistry
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• v.53 no.1
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• pp.13-20
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• 2010

Biological activities such as anti-oxidative and anti-microbial of the Seungmakalgeuntang, a traditional prescription, were evaluated. The electron donating ability of water, ethanol, supercritical fluid and 1,3-butylene glycol extract of Seungmakalgeuntang showed more than 50% at a 100 ppm concentration. At a 1000 ppm concentration, the superoxide dismutase-like activities of ethanol and supercritical fluid extract of Seungmakalgeuntang showed less than 50%. xanthine oxidase inhibition effect of the supercritical fluid extract showed more than 70% at a 1,000 ppm concentration, which was higher than vitamin C. From the measurement on lipid oxidation, the $Fe^{2+}$ chelating abilities of the supercritical fluid extract of Seungmakalgeuntang was more than 60% at a 100 ppm concentration. Also the $Cu^{2+}$ chelating abilities of supercritical fluid extract Seungmkalgeuntang was showed more than 60% at a 500 ppm concentration. Clear zones formed by sample against the human skin-resident microflora such as Staphylococcus epidermidis, Staphylococcus aureus and Propionibacterium acne of ethanol and supercritical fluid extract of Seungmakalgeuntang showed the highest among all the extracts tested using a 4mg/disc. The minimum inhibitory concentration (MIC) against both S. epidermidis and S. aureus showed 2,500 ppm in the extract of the supercritical fluid.

• Korean Journal of Environmental Agriculture
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• v.20 no.4
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• pp.252-257
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• 2001

To get the basic information for the water quality improvement and control of water resource at Mankyeong river stream, the water quality in four site of main stream and three site of branch stream at the upper stream were investigated mainly from February to August in 2000. The water temperature was affected by depth, flow rate of the water, and air temperature, and ranged 6.4 to $30.8^{\circ}C$. The pH, DO and BOD values of the water was $5.9{\sim}9.7$, $4.6{\sim}14.50\;mg/L$, and $0.1{\sim}11.8\;mg/L$ range, respectively. The content of total nitrogen, $NO_3-N$ and $NH_4-N$ was $1.19{\sim}10.61\;mg/L$, $1.00{\sim}5.93\;mg/L$, and ND $(non\;detected){\sim}2.79$ mg/L, respectively. The concentration of total phosphorus was ND to 1.14 mg/L. The concentration of Cl ion was $3.5{\sim}196.4\;mg/L$. The content of Fe and Mn was $0.002{\sim}0.100\;mg/L$ and $ND{\sim}0.04\;mg/L$, respectively. The contents of heavy metal Cd, Cu, and Zn were $ND{\sim}0.03\;mg/L$, $ND{\sim}0.05\;mg/L$, and $0.001{\sim}0.17\;mg/L$, respectively. Pb was not detected in all the samples. The pH, total nitrogen contents, and total phosphorus content were frequently exceeded the water quality standard for agriculture. The degree of water pollution was very varied by the sampling place. The water quality was generally polluted in the dry season more than in rainy season. The highest level of water pollution observed in the area of Samyea Bridge among the 7 sites.

• The Journal of the Petrological Society of Korea
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• v.18 no.1
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• pp.31-47
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• 2009

We performed petrological, geochemical, and geochronological study for the Pyeonghae granite gneiss and the Hada leuco-granite gneiss intruding the Paleoproterozoic meta-sedimentary rocks (pyeonghae formation and Wonnam formation) of the Pyeonghae area located in northeastem part of the Yeongnam (Sobaeksan) massif. The Pyeonghae granite gneiss generally has higher abundance of mafic minerals (biotite etc.), and posesses higher ${Fe_2}{O_3}^t$, MgO, CaO, $TiO_2$, $P_{2}O_{5}$ contents but lower $SiO_2$ and $K_{2}O$ contents than the Hada leuco-granite gneiss which tends to have slightly high $Al_{2}O_{3}$ and $Na_{2}O$ contents and slightly high larger negative Eu anomalies. However both gneisses reveal very similar REE concentrations and chondrite-normalized patterns and apparently show differentiation trend affected by crystallization of biotite, plagioclase, apatite and sphene. Their peraluminous and calc-alkaline chemistry suggests tectonic environment of volcanic arc. SHRIMP Zircon U-Pb age determinations yield upper intercept ages of $1990{\pm}23\;Ma$ ($2{\sigma}$) and $1939{\pm}41\;Ma$ ($2{\sigma}$), and weighted mean $^{207}Pb/^{206}Pb$ ages of $1982{\pm}6.3\;Ma$ ($2{\sigma}$) and $1959{\pm}28\;Ma$ ($2{\sigma}$) for the Pyeonghae granite gneiss and the Hada leuco-granite gneiss respectively, showing overlapping ages within the error. Our study suggests that the Precambrian granitoids in this area intruded contemporaneously with the Buncheon granite gneissin volcanic arc environment.