• Asian Journal of Turfgrass Science
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• v.16 no.1
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• pp.31-40
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• 2002

This study was conducted to analyze the correlation of soil physical properties and growth of turfgrass on the ground of Olympic-mainstadium. Soil hardness and turf visual quality were measured at 77 plots (10m x 10m divided each) independently and analyzed correlation later. Physicochemical properties of the topsoil analyzed from three typical levels of the severely, moderately, slightly compacted areas. The ground showed high hardness at the center circle and the goal line, but low at the end line areas. On the contrary, visual quality rate of turfgrass was low at the center circle and the goal line, but high at the end line areas. The correlation was shown a significant negative value on soil hardness between turf visual quality Soil hardness seems to be accelerated by the improper soil texture of sandy loam which contained a large amount of finer particle of silt (10.7%) and clay (11.1%) which values exceeded for USGA (United State Golf Association) recommendation. Deterioration of turf quality resulted initially from improper construction and followed by high soil compaction with continuous uses of the ground without proper maintenance. To perform the international quality of the turf ground, the initial construction procedures should be followed by standard specifications of sport ground.

• Polymer(Korea)
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• v.34 no.5
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• pp.398-404
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• 2010

We fabricated sponge and poly(lactide-co-glycolide)(PLGA) scaffolds impregnated demineralized bone particle(DBP)(DBP/PLGA) and investigated proper condition to proliferation and phenotype maintenance of intervertebral disc(IVD) cells by comparison between DBP/PLGA scaffold and DBP sponge. DBP/PLGA scaffolds were prepared by solvent casting/salt leaching. Human IVD cells were seeded in scaffolds of two types. Cell viability and proliferation according to scaffolds were analyzed by WST assay and SEM. RT-PCR was assessed to measure mRNA expression of aggrecan and type II collagen of human IVD cells. In WST assay results, cell viability in scaffolds impregnated DBP/PLGA scaffold were higher than DBP sponge. We could observe that disc cell mRNA expressed better in DBP/PLGA scaffold than DBP sponge. We concluded that the using of DBP/PLGA in terms of scaffold fabrication for bio-disc with human IVD cells is helpful growth of disc cells maintenance of phenotypes.

• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.2
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• pp.101-107
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• 2001

The experiment was conducted to investigate the agricultural utility of macro-porous calcium-silicate rnineral(CellCaSi) as topsoil mixture, as well as to estimate as a soil conditioner. The bulk density of CellCaSi which is consisted of various particle sizes ranging from 1mm to 3.35mm was about $0.42g/cm^3$, and its maximum porosity was approximately 81.4%. We also investigate gerrnination rates for Cabbage and Lettuce to obtain the suitable mixing ratios of CellCaSi with topsoil. Among 4 different mixing ratios, the germination rates of ropsoil mixed with 10% of CellCaSi were 94.1% and 64.6% for Cabbage and Lettuce, respectively resulted in the mosr suitable for germination. The growth rates for Cabbage and Lettuce showed thar 10% and 20% of CellCaSi treatments signification influenced the fresh weight. To observe the adsorption capacity of CellCaSi, CellCaSi was treated with a chemical fertlizer(N:P:K=18:18:18). lncreasing the contents of N, P and K, the amounts of adsorption by CellCaSi for these element also increased. The most suitable types nutrient resources for growth condition of Cabbage, and Lettuce were Fer-1 and Fer-0.5.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.16 no.3
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• pp.101-105
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• 2006

We fabricated the nano $TiN_x$ by making of reaction between titanium powder and $Si_3N_4$ during planetary milling. The $TiN_x$ powder was sintered by spark plasma sintering machine after mixing with 50 wt% of titanium powder, and the sintered body was heat-treated at $850^{\circ}C$ in order to investigate its hardness property at the elevated temperature. We analyzed crystal structure by XRD. We observed the peaks of $TiN_{0.26}$ and TiN after 10 hours milling, and we observed TiN peak mainly after 20 hours milling. The reacted particle size distribution was investigated by FE-SEM. Increase of milling time, the size of reacted particles was decreased and the $10{\sim}20nm$ size of $TiN_x$ on the surface of titanium and $TiN_x$ was observed after 20 hours milling. The micro-Vickers hardness of mixed sintered body was about $1050kgf/mm^2$.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.24 no.1
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• pp.15-20
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• 2014

In this research, the geopolymer was fabricated using municipal solid waste incineration ash (denoted as MSWIA) slag and alkali activator, NaOH and its properties were analyzed. Particularly, the effects of NaOH molarity, particle size of MSWIA, and liquid/solids ratio on the compressive strength of geopolymers were investigated. The compressive strength of geopolymers fabricated increased with finer grain size of MSWIA, and optimum value of the liquid/solids ratio was identified as 0.13. As the molarity of the NaOH increased, the compressive strength of geopolymers was increased. Even more the 20 M of NaOH, but the strength was not increased. The calcium aluminum silicate and calcium aluminum silicate hydrate zeolites were generated in the geopolymer fabricated with more than 20 M of NaOH, with some unreacted silica and unknown crystals remained. The highest compressive strength, 163 MPa, of geopolymer was appeared at conditions of curing temperature $70^{\circ}C$, and 20 M of NaOH, indicating that the high concentration of NaOH accelerates the geopolymer reaction and dense microstructure. The high-strength geopolymer fabricated in the present study is expected to contribute significantly to develop the field of cement alternative substances and to improve the recycling rate of MSWIA slag.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.26 no.5
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• pp.193-200
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• 2016

Characteristics of $SrAl_2O_4:Eu^{2+}$, $Dy^{3+}$ phosphorescent phosphors synthesized by solid state reaction and polymerized complex method were comparatively analyzed. In order to evaluate thermal stability of $SrAl_2O_4:Eu^{2+}$, $Dy^{3+}$ phosphorescent phosphors at high temperature, phosphorescent properties of $SrAl_2O_4:Eu^{2+}$, $Dy^{3+}$ were investigated with thermal treatment at $1250^{\circ}C$ under reducing atmosphere, which was the general heat treatment conditions for ceramic manufacturing process. The phosphorescent properties of thermally treated $SrAl_2O_4:Eu^{2+}$, $Dy^{3+}$ phosphors synthesized by solid state reaction and polymerized complex method were investigated. The crystal structure and crystallite size were observed through XRD analysis. Microstructure and particle size of thermally treated $SrAl_2O_4:Eu^{2+}$, $Dy^{3+}$ phosphors were analyzed by SEM and PSA. Photoluminescence and afterglow characteristics of thermally treated $SrAl_2O_4:Eu^{2+}$, $Dy^{3+}$ phosphorescent phosphors were measured by spectrofluorometer.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.4
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• pp.327-332
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• 1999

Manganese (Mn) oxides in soils have been a research subject since they react with nutrients and contaminants and Mn itself is an essential element for plant growth. Birnessite was synthesized in the presence of iron (Fe) in the precipitating solution. Influence of Fe, one of common elements in soils, on crytallinity, morphology, and chemical reactivity of birnessite was examined using X-ray diffraction (XRD), electron microscope, canon exchange capacity (CEC), and chromium (Cr) oxidation capacity. With increasing Fe concentration in the precipitating solution, crystallinity and crystal size decreased. Hexagonal plates of the birnessites formed at low Fe concentration were dominant and replaced more and more by aggregate of small particles with increasing the Fe concentration. There is no significant change in CEC with changing the Fe concentration. Chromium oxidation capacity of the birnessite increased with increasing the Fe concentration. Iron in the precipitating solution poisoned crystal growth by adsorption on the surface and increased nucleation. Since Fe is a common constituent under pedogenic environment and Fe and Mn oxides often coexist in Mn oxide nodules, the birnessite with small particle, low crystallinity, and high chemical reactivity is the form which is more likely to be formed in soils. The high CEC ($140cmol_ckg^{-1}$) and oxidation capacity of birnessite indicate that birnessite can be used in environment and agriculture.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.2
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• pp.15-21
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• 2019

We investigated the structural, electrical and optical properties of zinc oxide (ZnO) ultra-thin films grown at $150^{\circ}C$ by atomic layer deposition (ALD). Diethylzinc and deionized water were used as metal precursors and reactants, respectively, for the deposition of ZnO thin films. The growth rate per ALD cycle was a constant 0.21 nm/cycle at $150^{\circ}C$, and samples below 50 cycles had amorphous properties due to the relatively thin thickness at the initial ALD growth stage. With the increase of the thickness from 100 cycles to 200 cycles, the crystallinity of ZnO thin films was increased and hexagonal wurtzite structure was observed. In addition, the particle size of the ZnO thin film increased with increasing number of ALD cycles. Electrical properties analysis showed that the resistivity value decreased with the increase of the thin film thickness, which is correlated with the decrease of the grain boundary concentration in the thicker ZnO thin film due to the increase of grain size and the improvement of the crystallinity. Optical characterization results showed that the band edge absorption in the near ultraviolet region (300 nm~400 nm) was increased and shifted. This phenomenon is due to the increase of the carrier concentration with the increase of the ZnO thin film thickness. This result agrees well with the decrease of the resistivity with the increase of the thin film thickness. Consequently, as the thickness of the thin film increases, the stress on the film surface is relaxed, the band gap decreases, and the crystallinity and conductivity are improved.

• Journal of the Korean GEO-environmental Society
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• v.12 no.5
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• pp.43-50
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• 2011

As a result of population growth and economic growth, household and industrial wastes continue to rapidly increase every year. Especially, sewage sludge produced at final stage is increasing with the constant construction and putting in good order of the sewage plant. In addition to the government's prohibition for filling up the sludge, it became more and more difficult to discharge wastes to the sea as London Dumping Convention '96 came into effect. And sewage sludge and the livestock wastes are expected to be thoroughly prohibited from discharging to the sea from 2012. So we need desperately economical and useful alternatives to compact and reuse these wastes. The purpose of this study is to evaluate the utilization of solidified sludge-soil mixture as an enhancement and covering material. To determine the proper mixed ratio of solidified sludge, this study conducted basic physical properties tests, compaction tests, uniaxial compression tests, and permeability test. It was found that the higher the ratio of solidified sludge, the lower the coefficient of permeability. Upon the results of particle size distribution, the mixed ratio of solidified sludge that meet the enhancement material condition was 59% or lower for SP granite soil and 48% or lower for SM granite soil respectively.

• Journal of Bio-Environment Control
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• v.31 no.2
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• pp.114-124
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• 2022

The Saemangeum has a dry surface characteristic with a low moisture content ratio due to the saline and silt soil, so the vegetation cover is low compared to other areas. In areas with low vegetation cover, wind erosion has a high probability of scattering dust. If the vegetation cover is increased by cultivating crops that can withstand the Saemangeum reclaimed environment, scattering dust can be reduced by reducing the flow rate at the bottom. Thus, the purpose of this study is to analyze the effect of suppressing the generation of fine dust and scattering dust by cultivating winter forage crops on the Saemangeum reclaimed land. While growing 0.5 ha of barley and 0.5 ha of triticale in Saemangeum reclaimed land, the concentration of fine dust was monitored according to agricultural work and growth stage. Changes in the concentrations of PM-10, PM-2.5, and PM-1.0 were monitored on the leeward, the windward and centering on the crop field. As a result of monitoring, PM-1.0 had little effect on crop cultivation. the concentration of PM-10 and PM-2.5 increased according to tillage and harvesting, and tillage had a higher increasing the concentration of PM-10 and PM-2.5 than that of harvesting. According to the growth stage of crops, the effect of suppressing scattering dust was shown, and the effect of suppressing scattering dust was higher in the heading stage than in the seedling stage. So, it was found that there was an effect of suppressing scattering dust other than the effect of land covering. Through this study, it was possible to know about the generation and suppression effect of scattering dust according to crop cultivation.