• Journal of the Korean Crystal Growth and Crystal Technology
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• v.30 no.2
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• pp.66-72
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• 2020

The difference of plasma resistance between the CAS glass bulk and coating films were compared. Plasma resistance was confirmed by analyzing the etch rate and the microstructure of the surface when the CAS glass bulk and the glass coating film were etched with CF₄/O₂/Ar plasma gas. CAS glass coating film was etched up to 25 times faster than the glass bulk. A statistically high correlation between the surface roughness and the etching rate of the coating film was derived, and thus, the high surface roughness of the coating film was determined to cause rapid etching. In addition, cristobalite crystals that has a low Ca content and a high Si content, was foamed on the glass coating film. Therefore, the CAS glass coating film is considered to have low plasma resistance compared to the glass bulk.

• Korean Journal of Environmental Agriculture
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• v.20 no.4
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• pp.244-251
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• 2001

This study was performed to investigate the recovery efficacy of 2-methylisobomeol (2-MIB) and Geosmin, odor contaminants produced by algae, by pretreatment techniques, and also to investigate both adsorption characteristics and removal efficiency to get some information for the effective removal of 2-MIB and Geosmin by batch experiments. In pretreatment experiments, the best recovery efficiency of both odorants at 0.2 and $2\;{\mu}g/L$ in raw water was 30 mL of sampling size, 9 g NaCl for salting out headspace of sampling phase and 40 minutes of adsorption. At the best condition, the recovery efficiency of 2-MIB was 85% at $0.2\;{\mu}g/L$ and 95% at $2\;{\mu}g/L$, whereas the efficiency of Geosmin was lower than that of 2-MIB : 61% at $0.2\;{\mu}g/L$ and 81% at $2\;{\mu}g/L$. In batch experiments, the removal efficiency of the Geosmin and 2-MIB by adsorbents using distilled water were increased in comparison with raw water, the efficiency in raw water was little different by their concentrations. When these results were applied to the Freundrich adsorption isotherm, the K value of 2-MIB for zeolite, coal activated carbon, and coconut activated carbon was 0.671, 1.811, and 1.340, respectively, and the value of Geosmin was 0.6125, 1.771, and 1.5191, respectively. Thus the adsorption efficiency of 2-MIB and Geosmin was in the order of zeolite, coconut activated carbon, coal activated carbon.

• Economic and Environmental Geology
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• v.47 no.3
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• pp.255-263
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• 2014

Conflict minerals refer to minerals mined in conditions of armed conflict, especially as in the eastern provinces of the Democratic Republic of the Congo. The common conflict minerals are cassiterite, wolframite, coltan(columbite-tantalite ore), and gold, which are mined and extracted from the Eastern Congo. These minerals are essentially used in the manufacture of a variety of devices, including consumer electronics. To end the violent conflict in the Democratic Republic of the Congo (DRC) and in surrounding countries, it is necessary to block the supply route of conflict minerals which has been partially financed by the exploitation and trade of conflict minerals. The Dodd-Frank Wall Street Reform and Consumer Protection Act, passed into law in July 2010 and it contains requirements that U.S. companies report to the Securities and Exchange Commission(SEC) on the origin of conflict minerals and show due diligence of OECD. The goal of the act is to cut direct and indirect funding of armed groups engaged in conflict.

• Journal of Conservation Science
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• v.36 no.2
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• pp.143-151
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• 2020

In the present article, we have analyzed five slags excavated from the Unified Silla period iron smelting site, i.e., location 4-2 of the Inje Bupyeong-ri site, to investigate the iron smelting process. The total Fe content of the slag excavated from the Inje Bupyeong-ri site ranged between 3.65 and 23.78 wt%, lower than that of typical slag, and deoxidation agent of the slag ranged between 65.92 and 88.96 wt%, higher than that of typical slag. These results suggest that the recovery rate of iron was significantly high. Furthermore, cristobalite was detected in most of the samples, and the furnace temperature, estimated by substituting the analyzed data into the FAS and FCS state diagrams, was confirmed as 1,600℃ or more. These results suggest that the operation at the Inje Bupyeong-ri site was performed at a temperature capable of producing cast iron by completely melting the carbon-containing iron. Observation of the microstructure showed that the iron fragments excavated at the Inje Bupyeong-ri site were identified as white cast iron. Steadite from the ternary iron-carbon-phosphorus system was observed in the white cast iron structure. These results show that indirect smelting was performed when the iron smelting by-products were produced. Based on the analysis results, it was confirmed that the Inje Bupyeong-ri site was the indirect smelting site in the Unified Silla period.

• Korean Journal of Plant Resources
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• v.21 no.2
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• pp.111-116
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• 2008

This study was carried out to induce plant regeneration via multiple shoot formation from sucker explants of Rubus fruticosus L. ${\times}$ R. parvifolius L. To induce adventitious shoots, the sucker explants were sterilized in 1.2% sodium hypochlorite (NaOCl) solution, and then were cultured on the full and 1/2 MS solid medium supplemented with BA (0.1, 0.5, 1.0, $2.0mg{\cdot}L^{-1}$). After 4 weeks of culture, the highest frequency (83.3%) of shoot formation from sucker explants was obtained from the full MS medium with $1.0mg{\cdot}L^{-1}$ BA. The highest shoot number (3.7) per explant was obtained from the full MS medium with $0.5mg{\cdot}L^{-1}$ BA. After 12 weeks of culture, the number of shoots (15.4) per explant was increased. The highest frequency (95%) of root formation was obtained from the 1/2 MS medium, when the explant with shoot were cultured on the full, 1/2 and 1/4 MS medium. The survival rate of the plantlets after transfer to plastic pots containing sand, soil, and vermiculite (1.1:1, vol.) was 95%. The results indicate that multiple shoot procedure can be applied for an efficient mass propagation of Rubus fruticosus L. ${\times}$ R. parvifolius L.

• Journal of the Korea Institute of Building Construction
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• v.11 no.2
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• pp.127-135
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• 2011

In this study, the engineering characteristics of outer wall insulation panels according to type of insulation materials, their combination, and the contents of insulation materials were tested. Vermiculate, ceramic bead, perlite and expanded polystyrene were used as insulation materials. Flexural strength and thermal conductivity depending on the insulation materials used were measured. It was found that the flow of fresh mortar significantly decreased with an increase in the contents of insulation materials. In terms of the effect of insulation materials on thermal conductivity, an increase in insulation materials resulted in a decrease of thermal conductivity. In particular, PL and EPS, when used together, have lower thermal conductivity than other materials. Regarding the flexural strength of the hardened mortar, the strength showed a tendency to gradually decrease according to the increase in contents of insulation materials, compared to that of the plain mortar. In terms of the flexural strength depending on various types of insulation materials and its combination, it was found that the flexural strength of cement mortar containing 3% of vermiculate(V)+ceramic bead(CB)+perlite(PL) was the highest among the specimens tested.

• Journal of the Korean earth science society
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• v.26 no.1
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• pp.78-92
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• 2005

Petrographical and petrochemical analyses for late Miocene basalts in Goseong-gun area. Gangwon province, were carried out to interpret the characteristics and the origin of magma. The basaltic rocks occurred as plug-dome in the summit of several small mountain and developed columnar jointing with pyroxene-megacryst bearing porphyritic texture. And the basalt contains xenoliths of biotite granite (basement rocks), gabbro (lower crustal origin) and Iherzolite(upper mantle origin). The basalts belong to the alkaline basalt field in TAS diagram and partly belong to picrobasalt and trachybasalt field. On the tectonomagmatic discrimination diagram f3r basalt in the Goseong-gun area. they fall into the fields for the within plate and oceanic island basalt. The characteristics of trace elements and REEs shows that primary magma for the basalt magma would have been derived from partial melting of garnet-peridotite mantle. This late Miocene basalt volcanism is related to the hot spot within the palte.

• Korean Journal of Plant Resources
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• v.18 no.3
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• pp.456-461
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• 2005

This study was carried out to induce plant regeneration via shoot formation from sucker explants of Rubus fruticosus L. To induce adventitious shoots, sucker explants were sterilized in $1.2\%$ NaOCl solution, and cultured on the MS solid medium supplemented with kinetin (0.5, 1.0, 3.0 mg/L) and BA (0.5, 1.0, 3.0 mg/L), respectively. As above, to induce adventitious shoots, sucker explants were cultured on the MS solid medium supplemented with IBA (0, 0.1, 1.0 mg/L) and BA (0, 0.1, 1.0, 2.0 mg/L). After 4 weeks of culture, the highest frquency $(100\%)$ of shoot formation from sucker explants was obtained from the medium with 1.0 mg/L BA. The highest shoot number per explant from in vitro shoot explants was 5.3. After 10 weeks of culture, the number of shoot per explant was increased. The highest frequency $(85\%)$ of root formation was obtained at 0.5 mg/L glycine medium, when the explant with shoot were cultured on the MS medium containing glycine at various concentrations from 0 to 2.0 mg/L. The survival rate of the plantlets after transfer to plastic pots containing sand, soil, and vermiculite (1:1:1, vol.) was $95\%$. The results indicate that micropropagation procedure can be applied for an efficient mass propagation of Rubus fruticosus.

• Clean Technology
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• v.18 no.2
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• pp.209-215
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• 2012

The performance and removal efficiencies of a pilot scale biofilter were estimated by using ammonia and hydrogen sulfide as the odorous gases. Expanded polyurethane foam coated with powdered activated carbon and zeolite was used as a biofilm supporting medium in the biofilter. Odorous gases from the sludge thickener of a municipal wastewater treatment plant were treated in the biofilter for 10 months and the inlet ammonia and hydrogen sulfide concentrations were 0.1-1.5 and 2-20 ppmv, respectively. The removal efficiencies reached about 100% at the empty bed retention time (EBRT) of 3.6-5 seconds except for the adaptation periods. The pressure drop of the biofilter caused by the gas flow was also low that the maximum attained was 31 mm $H_2O$ during the operation. Its stability was confirmed in the long term due to the fact that the biofilter and the polyurethane medium had a minimum plugging and compression. The microbial community on the medium is critical for the performance of the biofilter especially the distribution of ammonia oxidizing bacteria (AOB) and sulfur oxidizing bacteria (SOB). The distribution of Nitrosomonas sp. (AOB) and Thiobacillus ferroxidans (SOB) was confirmed by FISH (fluorescence in situ hybridization) analysis. The longer the operation time, the more microbial population observed. Also, the medium close to the gas inlet had more microbial population than the medium at the gas outlet of the biofilter.

• Journal of Life Science
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• v.17 no.6 s.86
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• pp.831-835
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• 2007

This study was carried out to obtain information about the valuable combination and concentration to produce good plants of cut gerbera flowers of 19 domestically - bred gerbera cultivars. BA and kinetin combination is more effective than NAA and BA combination to produce good plants and mass propagation of domestically - bredgerbera cultivars. Normally almost of 19 cultivars, mass propagation was more effective on the medium containing 1.0 mg/L BA + 0.5, 1.0 mg/L kinetin. But some cultivars, 'Sunnyeo', 'Oksaem','Piny', and 'Pink Light', vitrified plants were induced on MS medium high level of BA concentration(BA 1.0 mg/L), in comparison with those on the medium with low level of BA(0.1 mg/L).Fresh and dry weight, more effective on the medium containing BA 0.5 mg/L . Kinetin 0.1, 0.5 mg/L. Anatomical investigation of vitrified leaf, stomata of vitrified leaves were circular and inflated, where-as those of normal leaves.