• Analytical Science and Technology
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• v.23 no.6
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• pp.511-517
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• 2010

Dissolution procedure of vanadium pentoxide, which is widely used as a catalyst for production of sulfuric acid or an oxide reaction of the numerous organic compounds, was investigated. Reagent of vanadium pentoxide was completely dissolved in aqua regia-$H_2O_2$-HF solution, but plate type of vanadium pentoxide sample was not clearly dissolved with mixed acids. Thus, in order to establish the dissolution procedure for plate type of vanadium pentoxide, the solubility of vanadium pentoxide was investigated through comparison of acid treatment-fusion and microwave digestion methods. The optimized acid for dissolution of vanadium compound was found to be mixing acids of aqua regia, $H_2O_2$ and HF. Acid-fusion and microwave digestion methods have a similar property in the solubility of vanadium compound, but the latter was more quick and convenient procedure. The content of vanadium pentoxide was found to be $97.9{\pm}0.9%$ using an inductively coupled plasma atomic emission spectrometer after dissolution of a sample with the microwave digestion system.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.11 no.3
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• pp.1-11
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• 2008

Although landslides were frequently occurred under Tripterygium regelii and Rubus sp. vegetations, the damage of landslide was not observed in sasa (Sasa borealis) stands. These phenomena may be affected by forest vegetation types. This result suggested that the landslide occurred in Jirisan (Mt.) National Park may be closely related to water retention capacity at Sasa borealis stands. This study compared and analyzed the water retention capacity of each soil horizon of sasa, larch (Larix leptolepis) and mongolian oak (Quercus mongorica) stands. Soil bulk density in A horizon was lower in sasa (0.776g/$cm^3$) than in mongolian oak (0.828g/$cm^3$) and in larch stands (1.282g/$cm^3$). Water permeability in A horizon was 0.02055cm/sec for sasa, 0.00575cm/sec for mongolian oak, and 0.0007cm/sec for larch stands, respectively. The water permeability of sasa stand was about 3.6 times and about 29 times higher than in mongolian oak and in larch stands, respectively. This result indicates that water infiltration of soil surface during a rain event is more rapid in sasa than in other two stands. Soil organic matter content in B horizon was lower in larch (0.7%) than in mongolian oak (6.5%) and in Sasa (3.3%) stands. The solid ratio in A horizon was highest in larch among three stands, but that of mongolian oak and larch stands showed a similar rate. Pore space rates was 70.7% for A horizon and 70.6% for B horizon of sasa, 68.9% for A horizon and 70.6% for B horizon of sasa, 68.9% for A horizon and 70.6% for B horizon of mongolian oak forests and 51.7% for A horizon and 49.2% for B horizon of larch forests, respectively. According to pore space rates, the water retention capacity may be poor in larch stand compared with other two stands. Soil strength in sasa and mongolian stands was over 25kgf/$cm^2$ from 40cm depth, while the strength was over 25kgf/$cm^2$ from 25cm depth in larch stand. The result indicates that tree growth and water permeability in larch stand could be limited due to high soil strength. Larch stand was poor for soil pore space development to be offered to the water retention capacity, but water retention capacity of A horizon soil in sasa stand was high than that of other two stands. Therefore, establishment of sasa stand under larch stand could help to prevent landslides.

• Journal of The Korean Society of Grassland and Forage Science
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• v.31 no.2
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• pp.159-166
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• 2011

This experiment was carried out to investigate the effect of application of swine slurry (SS) and slurry composting-biofilteration liquid fertilizer (SCB) on productivity of sorghum${\times}$sorghum hybrid (SSH) and soil environment in reclaimed land of Sukmoon in Korea. Dry matter (DM) yields of SSH in the treatments of SS and chemical fertilizer (CF) were higher than those of in SCB treatment in reclaimed land, but DM yields in SS and CF did not show a significant difference as compared to SCB. Nutritive values of SSH were not different among CF, SS and SCB. In soil samples collected at the end of the experiment, the concentration of organic matter was significantly increased by SS and SCB as compare to that at the beginning of the experiment (P<0.05), whereas the concentration of total nitrogen was not affected by SS and SCB. To investigate the moisture content of soil, the soils were collected from three layers; surface (0~5 cm), intermediate (10~15 cm), and deep (20~25 cm) layer. The moisture contents of soils increased according to the soil depth and the soil moisture was immediately affected by the amount of rainfall. Therefore, we suggest that the cultivation of SSH using SS in reclaimed land is possible and that additional nitrogen fertilizer was surely applied in case of application of SCB to cultivate SSH.

• Journal of Korean Society for Atmospheric Environment
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• v.26 no.6
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• pp.606-615
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• 2010

This study aims to identify the characteristics of soil in Mongolia, one of the major Asian dust sources that influence the Korean Peninsula. Soil particle size was analyzed and the result shows that sand (57.5~97.3%) was identified prominently in most regions, followed by silt (2.5~34.7%) and clay (0.0~7.8%). Soil pH of the covered regions were in the range 7.1~10.1, either weak alkaline or strong alkaline. Analysis of ion species in the soil samples exhibited that $Na^+$ ($91.9\;mg\;kg^{-1}$), $Cl^-$ ($65.9\;mg\;kg^{-1}$), and $Ca^{2+}$ ($53.5\;mg\;kg^{-1}$) were detected more in the soil than other species such as ${SO_4}^{2-}$ ($19.2\;mg\;kg^{-1}$), ${NO_3}^-$ ($46.6\;mg\;kg^{-1}$), ${NH_4}^+$ ($3.9\;mg\;kg^{-1}$), $K^+$ ($22.0\;mg\;kg^{-1}$), and $Mg^{2+}$ ($10.2\;mg\;kg^{-1}$). As for heavy metal content in the soil, concentrations of soil-borne metals including Fe, Al, Ca, Mg, and K tended to be high, while metals that come from manmade sources Pb, Cd, Cr, V, and Ni were remarkably low. The concentration of organic carbon (OC) was relatively high at $15.9\;{\mu}g\;mg^{-1}$, while elemental carbon (EC), directly released in the process of fossil fuel combustion, was not detected at all or found in very small amounts. The result indicates that pollution from manmade sources scarcely occurred. The analysis results from this study may contribute to improving modeling accuracy by providing input data for Asian dust prediction models, and be used as base data for determining the process of physiochemical transformation of Asian dust during long-range transport.

• Journal of Animal Environmental Science
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• v.13 no.1
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• pp.53-58
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• 2007

This study was carried out to determine the effect of continuous application of animal liquid slurry on the growth and yield of rice in 2005. Field experiment was conducted under variable continuous application years of animal liquid slurry; 1, 3, 5 application years of slurry and chemical fertilizer as control plot. The effects of different application years of slurry on the growth characteristics and yield of rice were determined. The plant height and tiller's number of 1 year application of liquid slurry were lower than those of the chemical fertilizer plot. But in the plot of 5 years continuous application of animal slurry, the height and tillers of rice were higher than those of 1 year application. And the color of leaf 5 years application years plot was darker than that of the chemical fertilizer. Yield of the 5 years continuous application of slurry was 4% higher than that chemical fertilizer, but that of 1 year application was decreased 6% compared with chemical fertilizer. The long time application of animal slurry was increased content of organic matter, $P_2O_5$ and exchangeable caution(K) in soil.

• Journal of Life Science
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• v.20 no.1
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• pp.40-48
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• 2010

This study was carried out to investigate the physicochemical and functional properties of Yacon (Polymnia Sonchifolia) powder. The proximate composition of Yacon powder as a dry matter basis was 3.53% moisture content, 1.13% crude protein, 0.40% crude fat, 0.79% crude ash, 1.63% dietary fiber and 92.52% carbohydrate. The major free sugars were identified as fructose and glucose. Analysing total amino acids, 18 kinds of components were isolated from Yacon powder. The essential amino acid contained in Yacon powder accounted for 28.40% of total amino acid, while the non-essential amino acid accounted for 73.61%. Analysing total fatty acids, only 2 kinds - palmitic acid and lauric acid - were detected. Oxalic acid was the major organic acid. The contents of vitamin A, vitamin C and vitamin E were 0.057 mg%, 0.670 mg% and 0.001 mg%, respectively. The mineral contents of Yacon powder were in the order of Zn

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.7
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• pp.854-862
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• 2016

In summer 2010, we measured the concentration of dissolved oxygen (DO) and nutrients in the water collected at the bottom of Cheonsu Bay, off the west coast of Korea. We also measured nutrient fluxes across the sediment-water interface by deploying a fully-automated benthic lander, which collected time-series water samples inside a benthic chamber. We confirmed on-going hypoxia in the northern parts of the bay where polluted lake water was discharged. DO content in the water at the bottom was 2 mg/l, compared to 5 mg/l at the mouth of the bay in the south. Nutrient concentrations showed a trend that was opposite to that of DO. The variation of N/P ratios implies phosphate desorption and a release of nutrients caused by hypoxia. The organic carbon oxidation rate and oxygen consumption rate in the northern parts of the bay were about twice as fast as those at the mouth of the bay. Benthic fluxes of nutrients in the northern part of the bay were 4 to 6 times higher than those at the mouth. Our results imply that it is important to understand the role of hypoxia events to make an accurate estimation of material fluxes across the sediment-water interface.

• Food Science and Preservation
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• v.19 no.5
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• pp.751-756
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• 2012

Antioxidant capacity and acetylcholinesterase (AChE) inhibitory activity of the aqueous methanolic extract of Rhus javanica were investigated in vitro. The antioxidant properties was measured by radical scavenging assays using DPPH and $ABTS^+$ radicals. The AChE inhibitory efficacy of R. javanica was tested by Ellman's assay and the total phenolic content was determined using a spectrophotometric method. All tested samples showed a dose-dependent AChE inhibitory and radical scavenging activities. In particularly, ethyl acetate (EtOAc)-soluble portion from the methanolic extract of R. javanica showed significantly higher inhibitory activity than other organic solvent soluble-portions in an AChE and radical scavenging assay systems. These results suggest that R. javanica may be possess potential benefits which might be useful in development of antioxidant and anti-alzheimer's disease ingredient.

• Food Science and Preservation
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• v.18 no.5
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• pp.773-778
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• 2011

This study investigated the alcohol fermentation characteristics of citrus hydrolysate by adding various sugars(sucrose, honey, fructose and fructooligosaccharide). As a result, the alcohol content was shown to be similar among all the sugars. Fructose, glucose, sucrose and maltose were detected as a major free sugar. In particular, the contents of fructose and glucose were shown to be higher in sucrose addition, lactic, citric and malic acids were detected as major organic acids of citrus wine. When the sensory characteristics of citrus wines were compared, flavor was shown to have a sensory score of 5.1 in sucrose addition, showing the most preference. However, no significant difference in preference was found among the sugars. Color, taste and overall acceptability were shown to have the most preference in sucrose addition, and then in honey, fructose, and fructooligosaccharide in order. Therefore, a further study on the improvement of quality and sensory preference using aging process and complex sugars is required.

• Korean Journal of Plant Resources
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• v.12 no.2
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• pp.125-132
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• 1999

This study has investigated the growing features and vegetation of Acanthopanax chiisanensis and Acanthopanax koreanum in Mt. Jiri and Halla from Sep. 1997 to Aug. 1998. As to Acanthopanax chiisanensis, it occupied surrounding areas of Nogodan in Mt. Jiri of the height of 1,507m, ImgeolyoungJae of 1,300m and the Mt. Halla. of 1,100m of There were rather high constancy degree with Quercus mongolica, Schizandra chinensis, Hydrangen serrate for. acuminata, Acer pseudo-sieboldianum, Dryopteris crassirhizoma, Actaea asiatica, Thalictrum filamentosum, Abies koreana, Arundinella hirta from the sorts. The common species in Mt. Jiri and Halla are Acer pseudo-sieboldianum, Dryopteris crassirhizoma, Callicarpa japonica, Parthenocissus tricuspidata, Acer mono, Ligularia fischeri, Disporum smilacinum, Viola acuminata Aconitum kusnezofii. On the other hand, concerning of Acanthopanax koreanum community, it possessed the small areas of wedo weoltae village in Chejudo. In this area, a liana e.g. Dioscorea tenuipes, Hedera rhombea, Lygodium japonicum, Akebia quinata, Vitis thunbergii, Dunbaria villosa, Trachelospermum asiaticum var. intermedium, Vitis amurensis, Paederia scandens, lives with Pinux thunbergii, Celtis aurantiaca, Mallotus japonicus and so forth in tree layer and subtree layer. There is artificial change no move in the researching sites, Acanthopanax chiixanensis will be transformed into Abies koreana - Acanthopanax chiisanensis community. Soil characteristics showed the high value such as pH 6.56 and conductivity 0.258mmho/cm in Acanthopanax koreanum community of Mt. Jiri, they also indicated digit as follows: the content of organic matter and total nitrogen are from 25.16 through 25.35% and 7.58 through 9.30mg/g respectably. The soil characteristics at Acanthopanax chiisanensis community in Mt. Jiri and Halla, was high as like pH 5.76, conductivity 0.238mmho/cm, total nitrogen 9.30mg/g, total phosphorus 0.126mg/g in Mt. Halla.