• Journal of Korean Society of Forest Science
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• v.77 no.1
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• pp.73-82
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• 1988

This study was excuted to analyze the vegetational community structure of the Hongrudong valley the Mt. Gaya by three kinds of ordination techniques (polar, principal component analysis, reciprocal averaging). Eleven sites were sampled with the clumped method to analyze the vegetation structure. The result suggested that Hongrudong valley forest was divided by Pinus densiflora and Quercus aliena community. The relation between stand scores of ordination and soil pH, humus content, soil moisture had a tendency to increase significantly from P. densiflora to Q. aliena community. RA was the most effective method of this study. RA ordination was showed that successional trends of tree species seem to be from P. densijlora through Q. variabilis to Q. aliena, Carpinus laxiflora in the upper layer and from Lespedeza cyrtobotrva, Rhus spp., Rhododendron schlippenbachii through Fraxinus sieboldiana, Lindera obtusiloba to Euonymus oxyphyllus, Weigela subsessilis, Callicarpa japonica in the middle layer.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.2
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• pp.140-146
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• 1999

This research was conducted to investigate the changes of $NH_4-N$ in soil, nitrogen uptake by rice plant, nitrogen-use efficiency and rice yield by the application of latex coated urea(LCU) on 10-day old seedling transplanted with machine on paddy field, Jeonbuk series at the Honam area, from 1997 to 1998. Almost all nitrogen in LCU application as basal dressing in whole layer was dissolved until maximum tiller stage, the maximum dissolution time was productive tiller stage and $NH_4-N$ content of conventional plot with surface application of fertilizer were lowered at full periods. Nitrogen deficiency symptom were appeared at heading stage of 31.6% SPAD value and nitrogen concentration was 1.29% shoot. From heading stage to ripening stage, the necessity of nitrogen-fertilizer was $2.9kg\;ha^{-1}$ for the conventional split application plot and $11.9kg\;ha^{-1}$ for the whole layer application plot of LCU basal dressing. Nitrogen-use efficiency was higher at the LCU application plot than the conventional application plot and was increased for 12.7% by fertilization at panicle forming stage. The additional fertilization at panicle forming stage to basal dressing of LCU causes 13% yield increase.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.2
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• pp.126-130
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• 1983

This study was desinged to find out the effects of soil physical properties on root development of barley. Barley fields were selected in consideration of drainage class and texture. Soil hardness were measured at the field. Soil bulk density, air ratio and root distribution were obtained from the core samples. 1. The amount of roots were increased and the root were distributed deeper layers with better drainage class and finer soil texture. 2. Soil hardness was related to soil bulk density, and the regression coefficient was increased with clay content (Clay ; $r=0.837^{**}$, Clay loam ; $r=0.678^*$, and Sandy loam ; $r=0.654^*$). 3. There was a highly negative correlation ($r=-0,846^{**}$) between bulk density of subsoils and amount of roots and the root developments were markedly reduced in soil bulk density of $1.4g/cm^3$. 4. Bulk density of subsoils was decreased with worse soil drainage and finer texture. Especially, in case of clayey soil at imperfectly or moderately drained soils, the air phase was less than 20% and the barley growth was worse. 5. Root development were related to hardness in surface, bulk density and ok phase in 10-30cm layer, and air phase in 30-50cm layer.

• Journal of the Korean Vacuum Society
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• v.10 no.2
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• pp.234-240
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• 2001

The diffusion barrier properties of TiN by using Cu(Mg) alloy film have been investigated. Cu(Mg) alloy film was deposited on air-exposed TiN film. Upon annealing, interfacial MgO of 100 $\AA$ has been formed due to the reaction of Mg with oxygen existed on the surface of TiN. Combined MgO/TiN structure prevented the interdiffusion of Cu and Si up to $800^{\circ}C$. To improve the adhesion of Cu(Mg) alloy film to the TiN, TiN layer was treated by $O_2$ plasma, followed by vacuum annealing at $300^{\circ}C$. It was found that increased oxygen on the surface of TiN film by plasma treatment enhanced segregation of Mg toward the interface, resulting in the formation of dense MgO layer. Improved adhesion characteristics have been formed through this treatment. However, increased power of $O_2$ plasma led to the formation of TiO$_2$ and decreased the Mg content to be segregated to the interface, resulting in the decrease in adhesion property. In addition, the deposition of 50 ${\AA}$ Si on the TiN enhanced the adhesion of Cu(Mg) alloy to TiN without deteriorating the TiN diffusion barrier characteristics.

• Journal of the Mineralogical Society of Korea
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• v.15 no.3
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• pp.221-230
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• 2002

Weathering of biotite shows a biotite-vermiculite-kaolinite sequence at the early stage, but presents biotite-kaolinite sequence without a significant intermediate phase (vermiculite) at the late stage from the weathering profile of the granitic gneiss. Secondary 1:1 phyllosilicates are kaolinite and halloysite which show different weathering textures originated by a different formation mechanism. Kaolinitization began from the edges of biotite and propagated toward the interior of grain along a multilayered front. $10 \AA$ layers of biotite are interleaving with $7\AA$ layers of kaolinite and c-axis of two phases is consistent. Kaolinite pseudomorph of biotite is isovolumetric, compared to the biotite boundary and includes many band-like porosities parallel to the cleavage. Platy kaolinite formed by 1:1 layer fur layer replacement of biotite. Halloysitization proceeded outward from the grain edges which were foliated as fine flakes and bent at the right angle for cleavage Halloysites were extensively fanning out and greatly increased the volume of grain. This indicated that halloysite tubes were formed by epitaxial overgrowth on the surface of biotite with import of Si and Al from the external solution by dissolution of plagioclase. These halloysites have abnormally high Fe content ( ~11%).

• Journal of Nutrition and Health
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• v.29 no.1
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• pp.112-121
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• 1996

The study was designed to observe the effect of blend fat calculated from the foods consumed in Korean with those of perilla oil, beef tallow and corn oil on colonic mucosal phospholipid fatty acid composition and the levels of TXB2 and diacylglycerol (DAG) which were known as biomarkers for cancer. Male Sprague Dawley rats, at 7 weeks of age, were divided into control and 1, 2-dimethylhydrazine (DMH)-treated group, and each group was subdivided into four groups. The experimental diets contained one of four dietary fats, blend fat (BF), perilla oil(PO), beef tallow (BT) or corn oil (CO), at 15% (w/w) level. At the same time, each rat was injected with saline for control group or DMH twice a week for 6 weeks to give total dose of 180mg/kg body weight. DMH injection, regardless of the type of dietary fats, significantly increased the levels of PGE2 and TXB2 in colonic mucosal layer compared to control (p<0.01). However, the level of eicosanoids was influenced by the types of dietary fats in both control and DMH group. In control groups, colonic mucosal level of TXB2 was higher in beef tallow group, but lower in perilla oil group compared to that of blend fat (p<0.01). In DMH groups, the level of TXB2 was higher in beef tallow and corn oil groups(p<0.05). The level of PGE2 showed the same trends with TXB2 and beef tallow most significantly increased the level of PGE2. DMH treatment did not influence on tissue fatty acid profile, which was directly reflected by dietary fatty acid composition. Proportions of C18 : 2 in colonic mucosal phospholipid well reflected dietary level of C18 : 2 showing the order CO>BF>PO>BT. The precentage of arachidonic acid(AA) in mucosal phospholipid was the highest by CO adn BT groups and the lowest by PO group. The incorporation of $\alpha$-linolenic acid in colonic mucosal phospholipid in perilla oil group was negatively correlated to the content of AA. Dietary level of C18 : 2 might not be the only controlling factor for the production of eicosanoids in colonic mucosa layer and might function with $\omega$3 fatty acids. The level of DAG was significanlty lower in PO group than that of BT group. Therefore, $\omega$3 $\alpha$-linolenic acid rich perilla oil could be very important dietary sourec in controlling eicosanoid production DAG level in cloln and recommenced to use more often in meal preparation to reduce the risk factor against colon cancer.

• KEPCO Journal on Electric Power and Energy
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• v.5 no.4
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• pp.287-293
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• 2019

Domestic thermal power plant fly ash is at a situation which emissions are increasing every year. Comparing to Fly Ash, Bottom Ash is only 15 %, but it's recycling rate is low, so most of them is being buried in the ground. However, landfill site of every power plant is full, and the construction of a new landfill is difficult. To solve this problem, the best solution is to use Bottom Ash as a landfill of large-scale civil engineering projects. The purpose of this study was to investigate the compression strength behavior characteristics of weak clay and uniaxial compression test to examine the applicability of surface soil solidification method of mixed soils mixed with industrial waste coal ash and weak clay which is buried in bulk. As a result of the test, the fluidity of the Mixed soil with clay + bottom ash + cement was improved to 200 mm at the water content of 91-92 %. The uniaxial compressive strength was also good for the mixed soils (clay + bottom ash + cement) meeting the required strength of 159 kN/㎡ at 28 days. However, the other samples did not meet the required strength. In this study, the prediction equations for the compression strength behavior by cement and curing period were presented.

• Microbiology and Biotechnology Letters
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• v.44 no.4
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• pp.512-521
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• 2016

A bacterial strain was isolated from a soil sample collected on Jeju Island, Korea. The strain, designated WJ-2, exhibited a high xylanase activity, whereas cellulase activity was not detected. The 16S rRNA gene sequence of WJ-2 was highly similar to type strains of the genus Streptomyces. A neighbor-joining phylogenetic tree based on 16S rRNA gene sequences showed that strain WJ-2 is phylogenetically related to Streptomyces atrovirens. Furthermore, DNA-DNA hybridization analysis confirmed that strain WJ-2 is a novel subspecies of Streptomyces atrovirens. The genomic DNA G+C content was 73.98 mol% and the major fatty acid present was anteiso-C15:0 (36.19%). The growth and xylanase production of strain WJ-2 were significantly enhanced by using soytone and xylan as nitrogen and carbon sources, respectively. Crude enzyme preparations from the culture broth of strain WJ-2 exhibited maximal total xylanase activities at pH 7.0 and $55^{\circ}C$. Thin-layer chromatography analysis revealed that the crude enzyme degrades beechwood xylan to yield xylobiose and xylotriose as the principal hydrolyzed end products.

• Journal of Conservation Science
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• v.36 no.2
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• pp.112-122
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• 2020

The purpose of this study was to find out the correlation through comparative analysis of used materials and manufacturing techniques such as firing characteristics for sherds excavated from celadon kiln site in Punggil-ri, Jangheung. The color difference of the sherds was very wide, and even in the microstructure of the cross section of the glaze layer and the body layer, the celadons, whitewares, blackware, and stonewares could not be characterized because they did not show distinct differences from each other. As a result of estimating the firing temperature through the analysis of constituent minerals and thermal analysis, most of them were estimated to have been fired at 1000℃, but some were fired at high temperatures above 1200℃. It was difficult to clearly distinguish between celadon and whiteware even in the major compositional content of bodies. In the statistical analysis, glaze could be classified three group according to the type of sherds, but the bodies of celadons, whitewares, and blackware classified into one similar group. It is considered that it is not more likely differences in raw materials but some ingredients were removed or added during the purification process. Conclusionally, in this kiln site was found through scientific analysis that there were technical attempts to produce various ceramics, and that the manufacturing techniques and materials of ceramics were in an early stage that was not stabilized.

• KIISE Transactions on Computing Practices
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• v.21 no.6
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• pp.430-435
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• 2015

IP-based, next generation digital broadcast systems transmit DASH segment files. Designed by the DASH system, DASH segment files provide variable quality of contents, while the size of DASH segment files varies even if the file has the same quality. Delays and inefficient use of resources are major challenges in the transmission of variable size DASH segment files in broadcasting systems. Traditional broadcasting transmission systems are designed according to characteristics of physical layer of broadcast, and thus, delay and inefficient resources use is difficult to find. Yet, transmission content quantities continue to rise in the next-generation broadcasting systems (e.g. FHD, UHD (4k, 8k)) with variability of the segments file size as well. Resources for next-generation broadcast are more abundant than traditional broadcast with recent development, but continue to be limited and fixed. Resource delay and inefficiency are important but has not been extensively studied. We propose a transmission structure solution to analyze the delay and efficiency of the resource as each DASH segment file is transmitted, and have further performed simulation studies.