• Korean Journal of Environmental Agriculture
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• v.17 no.1
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• pp.48-53
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• 1998

The purpose of this study was to compare heavy metal concentrations in uncontaminated soil with those in soil influenced by industrial activities, and to investigate the relationship between change of heavy metal content and the kind of industry at the Iksan 1st Industrial Complex that has started since 1975. Soils sampled in 0-3㎝ and 3-6㎝ soil depth, respectively were analized for content of Cd, Cu, Ni, Pb and Zn. Change of heavy metal content in soil of the industrial complex were more accumulated 16 to 25% of Cd and Cu, 93% of Pb and Zn, respectively in samples compared with natural soil uncontaminated. But there was no different in Ni content between two soil. Distribution of Cd in soil layer of 0 to 3cm was the highest concentration of 5 ppm more at the textile industries, and then higher at the chemicals and the food processing industries. In 3 to 6㎝ soil layer Cd content was the highest concentration of 5 ppm more at the metal processing industries, and then higher at the textile industries. Cd accumulation in soil was different according to a kind of industry and soil depth. Cu content was the highest value of 400 ppm more in soil layer of 0 to 3cm at the manufacturing electric wires industry area and showed the accumulation phenomenon in soil layer 3 to 6cm at the ohmmeter, machines and electric wires industry area. Ni content was 35 ppm more in soil of the metal plating and processing industries regardless of soil sampling layer. Then it was 25 ppm more in soil of the building stones and semiconductor industries. Pb content was from 400 to 1000 ppm in soil of the chemicals and textiles industries regardless of soil sampling layer. Zn content was 1200 ppm more in soil of the chemicals and silk fabrics industries regardless of soil depth, and then lower in order to soil of leather processing${\le}$metal plating industries. In conclusion, changes of heavy metal kinds and content in soil of this industrial complex area were caused by the type or kinds of industrial activities. Changes of Pb and Zn content in soil were dominated at this area.

• Journal of the Korean institute of surface engineering
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• v.35 no.3
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• pp.133-140
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• 2002

The Ti-Si-N coating layers were synthesized on SKD 11 steel substrate by a DC reactive magnetron co-sputtering technique with separate Ti and Si targets. The high resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS) analyses for the coating layers revealed that microstructure of Ti-Si-N layer was nanocomposite, consisting of nano-sized TiN crystallites surrounded by amorphous $Si_3$$N_4$ phase. The highest hardness value of about 39 GPa was obtained at the Si content of ~11at.%, where the microstructure had fine TiN crystallites (about 5nm in size) dispersed uniformly in amorphous matrix. As the Si content in Ti-Si-N films increased, the TiN crystallites became from aligned to randomly oriented microstructure, finer, and fully penetrated by amorphous phase. Free Si appeared in the layers due to the deficit of nitrogen source at higher Si content. Friction coefficient and wear rate of the Ti-Si-N coating layer significantly decreased with increase of relative humidity. The self-lubricating tribe-layers such as $SiO_2$ or (OH)$Si_2$ seemed to play an important role in the wear behavior of Ti-Si-N film against steel.

• The Korean Journal of Ecology
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• v.13 no.4
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• pp.285-295
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• 1990

Floristic composition and soil properties were analyzed in red pine($Pinus densiflora$) communities in the limestone areas. Tanyang, Ch ungbuk Province in Korea. The tree layer was composed of $Juniperus rigida, Quercus dentata, Q. mongolica$ and others as well as $P. densiflora$, all of which also appeared in soils of grinite origin The shrub layer was dominated by $Q. dentata, Lespedeza cyrtobotrya, Securinega suffruticosa, Abelia coreana$ and $Uimus davidiana$ for $suberosa$. Among these $A. coreana$ and $U. davidiana$ for $suberosa$ belonged to calcicole plant. The herb layer dominated by $Carex lanceolata$. Soil pH ranged 7.9-8.3. Total nitrogen and available phosphorus content of the soil were lower than those of noncalcareous soils. However, exchangeable calcium and magnesium content were 10 times and 2~3 times greater than those of noncalcreous soils, respectively. The difference of soil texture between top soil(loam soil) and subsoil(sand soil), and higher soil organic matter content than noncalcareous red pine forest soils seemed related to the casts forming activities of earthworms.

• Journal of the Korean Ceramic Society
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• v.52 no.4
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• pp.294-298
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• 2015

Blocking layers with nano carbon blacks (NCBs) were prepared by adding 0.0 ~ 0.5 wt% NCBs to the $TiO_2$ blocking layer. Then, dye sensitized solar cells (DSSCs) were fabricated with a $0.45cm^2$ active area. TEM and micro-Raman spectroscopy were used to characterize the microstructure and phases of the NCBs, respectively. Optical microscopy and AFM were used to analyze the microstructure of the $TiO_2$ blocking layer with NCBs. UV-VIS-NIS spectroscopy was used to determine the band gap of the $TiO_2$ blocking layer with NCBs. A solar simulator and potentiostat were used to determine the photovoltaic properties and impedance of DSSCs with NCBs. The energy conversion efficiency (ECE) increased from 3.53 to 6.20 % when the NCB content increased from 0.0 to 0.3 wt%. This indicates that the effective surface area and electron mobility increased in the $TiO_2$ blocking layer with NCBs. However, the ECE decreased when the NCB content was increased to over 0.4 wt%. This change occurred because the effective electron transport area decreased with the addition of excessive NCBs to the $TiO_2$ blocking layer. The results of this study suggest that the ECE of DSSCs can be enhanced by adding the appropriate amount of NCBs to the $TiO_2$ blocking layer.

• Journal of the Korean Vacuum Society
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• v.9 no.4
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• pp.436-441
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• 2000

Plasma nitrocarburising is a thermochemical heat treatment, and can be used for plain carbon steels and low alloy steels to improve wear, corrosion and fatigue resistance. The process is performed on automotive parts, machinery parts and engineering tools. However, it is still facing problems in obtaining a mono $\varepsilon$ phased compound layer. Therefore, the aim of this research is to investigate the possibility of forming a mono $\varepsilon$ phased compound layer using a gas mixture of nitrogen and methane. It was found that high nitrogen contents were essential for the production of $\varepsilon$ phase compound layer and with increasing methane content in the gas mixture, $\varepsilon$ phase compound layer was favoured. In addition, when the methane content was further increased, cementite was observed in the compound layer. $\gamma$' phase was produced after 10 minutes treatment time and cementite was formed in the compound layer resulting in decreasing the thickness of the compound layer.

• Journal of the Korean Institute of Landscape Architecture
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• v.28 no.5
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• pp.39-47
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• 2000

This study is to investigate the conditions closely related to the establishment of vegetation in the riparian zone: the soil condition, an important factor along with climate and light. Especially, the soil structure of the microtopographical formations in the specific area known as the riparian microtopographical zone investigated. In addition, the effect of the riparian microtopographical features on the ground water level, soil moisture content, and vegetation was studied. The results of this study are as follows; 1) At all sample sites, below the sand layer, a gravel layer is always present. This is the result of past floods. 2) Although Salix koreensis experiences frequent disturbances such as increase in river level and floods, this vegetation establishes itself in the most secure are in the microtopographical zone. 3) The growth of Phragmites japonica is closely related to the underground water level. 4) It is clear that Miscanthus sacchariflorus grows concentrated in dry areas. 5) The soil accumulation conditions differ according to the soil moisture content of each microtopgraphical feature. Accordingly, the moisture content of the soil is clearly different within the microtopographical zone. The continuous and long-term investigation and research on the relation of riparian reproduction and the relevance with location surrounding factors are necessary in the future.

• Journal of Communications and Networks
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• v.15 no.2
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• pp.198-206
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• 2013

Recent advances in forward error correction (FEC) coding techniques were focused on addressing the challenges of multicast and broadcast delivery. However, FEC approaches can also be used for unicast content delivery in order to solve transmission control protocol issues found in wireless networks. In this paper, we exploit the error resilient properties of Raptor codes by proposing Raptor-based content delivery protocol (RCDP) - a novel solution for reliable and bidirectional unicast communication in lossy links that can improve content delivery in situations where the wireless network is the bottleneck. RCDP has been designed, validated, optimized, and its performance has been analyzed in terms of throughput and resource efficiency. Experimental results show that RCDP is a highly efficient solution for environments characterized by high delays and packet losses making it very suitable for intelligent transport system oriented applications since it achieves significant performance improvements when compared to traditional transport layer protocols.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.1
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• pp.74-81
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• 1995

In the proximate composition of the yams of home product, wild yam was most abundant in crude lipid and crude protein, and those content in the cultivated yams, cultivated long yam and cultivated short yam were similar. Cultivated long yam is the richest in crude ash. African yam had more crude lipid and crude protein compare to those of home product yams. Especially, the amount of crude lipid in African yam was four-fold of home product yams. In the mineral content, Ca was the richest mineral in four kinds of yam. The rest of mineral were in order of Fe, Mn and Zn. Among the home product yams, the Ca content of wild yam was higher than that of cultivated yam. The contents of Fe, Mn and Zn were also high in wild yam compared to cultivated yam. In the composition of free sugars, the sucrose content is the highest in wild yam, cultivated short yam and African yam. in order The fructose content was the most abundant in cultivated long yam and the next was sucrose. The composition of free fatty acids were in order of lactobacillic acid, palmitic acid and palmitoleic acid. Crude saponin contents of the home products were almost similar levle, but crude saponin of wild yam was more abundant than that of cultivated yam. And crude saponin of African yam was much more abundant compared that of other home product yams. there is not much difference in the kinds of saponin from the home product yams. However, the amount of each saponin from the home product yams was different. In case of African yam, 'b' saponin did not appear and 'e' saponin was higher compared with home product yams. In African yam, the bitter taste from ethyl acetate layer was the strongest, and the next was n-butanol layer. It is possible that there was a powerful UV absorption material in the bitter taste of ethyl acetate layer and also supposed that there were saponin and phenol is material.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.42 no.3
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• pp.184-192
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• 2019

Focusing on the emerging influencer market of SNS (Social Network Service), This study attempts to clarify the priority of Influencer characteristics when the customer decided to purchase products through the promotion of influencers. Since the influencer marketing differs from the Online information source marketing, this study has an academic implication in that integrated the influence of the characteristics of the Online information sources and the characteristics of SNS contents. For this purpose, through the literature research on Information sources and Influencers, the characteristics of influencers were reconstructed and priorities were derived using the AHP (Analytic Hierarchy Process) technique. The upper layer of the AHP structure was set to expertise, trustworthiness, social attractiveness, and content attractiveness, and the lower layer structured the model with 13 subfactors. The results are summarized as follows. First, in the result of combining the importance of the $1^{st}$ and $2^{nd}$ classes, the detailed factors of expertise and trustworthiness, ranked from the top to six, are largely influenced in purchasing decisions in influencer marketing. Second, content attractiveness is the third rank in the $1^{st}$ layer. Influencer marketing shows that content is more important than social attractiveness. Besides, the $7^{th}$ to $9^{th}$ positions of the overall rankings accounted for visual information, storytelling, and external attractiveness, which are the details of content attractiveness, and it is confirmed that it is more effective for influencer marketing to emphasize content attractiveness than social attractiveness. Although the influencer marketing differs from the existing information marketing, this study has an academic implication in that integrated the influence of the characteristics of the source and the characteristics of the contents.

• Journal of Korean Society of Forest Science
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• v.112 no.4
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• pp.490-501
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• 2023

Laboratory column tests were conducted to analyze infiltration and water redistribution processes on the basis of rainfall. To efficiently measure moisture content within soil layers, this research developed a predictive model grounded in a convolutional neural network (CNN), a deep learning technique. The digital images obtained during the column tests were incorporated into the established CNN. The moisture content of each soil layer over time was effectively measured. The measured values were also in relatively good agreement with the moisture content determined using the moisture sensors installed for each soil layer. The use of CNN enabled a comprehensive understanding of continuous moisture distribution within the soil layers, as well as the infiltration process according to soil texture and initial moisture content conditions.