• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.9
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• pp.536-542
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• 2018

Tin dioxide, $SnO_2$, is a well-known n-type semiconductor that shows change in resistance in the presence of gas molecules, such as $H_2$, CO, and $CO_2$. Considerable research has been done on $SnO_2$ semiconductors for gas sensor applications due to their noble property. The nanomaterials exhibit a high surface to volume ratio, which means it has an advantage in the sensing of gas molecules. In this study, SnO nanoplatelets were grown densely on Si substrates using a thermal CVD process. The SnO nanostructures grown by the vapor transport method were post annealed to a $SnO_2$ phase by thermal CVD in an oxygen atmosphere at $830^{\circ}C$ and $1030^{\circ}C$. The pressure of the furnace chamber was maintained at 4.2 Torr. The crystallographic properties of the post-annealed SnO nanostructures were investigated by Raman spectroscopy and XRD. The change in morphology was confirmed by scanning electron microscopy. As a result, the SnO nanostructures were transformed to a $SnO_2$ phase by a post-annealing process.

• Journal of Biosystems Engineering
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• v.11 no.2
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• pp.55-65
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• 1986

The resistance to the passage of airflow through various agricultural products is an important consideration in the design of an aeration or drying system. The amount of resistance to airflow varied widely from one kind of grain to another, and depended upon airflow rate, surface texture and shape of the particles, the size and configuration of voids, and foreign and fine material in the grain bed. The airflow rate was the major factor considered on this kind of study in the early stages. But these days, the studies on the resistance to airflow of grain affected by grain moisture content and foreign and fine material have been widely carried out. However the foreign an fine material in the grain bed could not be a major factor on the study in Korea because there were only a few grain process procedure after harvesting it. The objectives of this study were to investigate the effect of moisture content and airflow rate on airflow resistance to grain, and to develop a model to predict the static pressure drop across the grain bed as a function of moisture content and airflow rate. The rough rice varieties, Akibare, Milyang 15 (Japonica types), Samkwang, Backyang (Indica types)and covered barley variety, Olbori, which were harvested in 1985 were used in the experiment after cleaning them. Resistances to airflow of grain were investigated at four levels of moisture content (13-25%, wb.) for ten different airflow rates($0.01-0.15m^3/sm^2$). The results of this study are summarized as follows; 1. Theaverage bulk densities were $585.3kg/m^3$ for rough rice and $691.6kg/m^3$ for barley at the loose fill, and were $648.8kg/m^3$ for rough rice and $758.2kg/m^3$ for barley at the packed fill. The pressure drops at the packed fill beds were approximately 1.4 to 1.8 times higher than those at the loose fill beds. 2. The pressure drops across grain beds deceased with the increase of moisture content and increased with airflow rate. The decreasing rates of pressure drop across grain beds according to the moisture contents at the lower airflow rates were higher than those at the higher airflow rates, and the increasing rates of pressure drop according to the airflow rates at the lower moisture contents were higher those at higher moisture contents. 3. The pressure drop across barley bed were much higher than rough rice beds and the pressure drops across Japonica type rough rice beds were a little higher than Indica type. 4. The mathematical models to predict the pressure drop across grain beds as a function of moisture content and airflow rate were developed from these experiments.

• Journal of the Korean GEO-environmental Society
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• v.24 no.3
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• pp.23-27
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• 2023

Graphitic carbon nitride (g-C₃N₄) has been used as effective photocatalyst for degradation of antibiotics under visible light irradiation. However, the fast recombination of hole-electron pair may limit their photocatalytic efficiency. In our study, Ag was grafted on g-C₃N₄/g-C₃N₄ isotype heterojunction by a microwave-assisted decomposition method. The structure and physical properties of heterojunction photocatalyst were characterized through X-ray diffraction, UV-DRS, FT-IR, and Photoluminescence analyses. Ag decorated g-C₃N₄/g-C₃N₄ isotype heterojunction exhibited excellent photocatalytic activity for degradation of sulfamethoxazole under irradiation under visible light irradiation within 210 min, which is higher than g-C₃N₄/g-C₃N₄ isotype heterojunction and bulk g-C₃N₄. The addition of Ag may broaden the visible light absorption and restrict the recombination of hole-electron pair because of the surface plasmons resonance, resulting in the improving the photocatalytic activity.

• Korean Journal of Breeding Science
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• v.50 no.4
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• pp.387-395
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• 2018

This study was conducted to identify DNA markers related to resistance to herbicide containing mesotrione in Tongil type rice. Two Tongil type elite lines; Milyang154 and Suweon382, showed resistance to mesotrione, whereas the others were susceptible at 20 days after mesotrione application, and severe growth inhibition was observed in the remaining 13 lines. As a result of analysis of mesotrione resistance using 190 $F_2$ populations derived from a cross of Hanareum2 (susceptible) and Milyang154 (resistant), the mesotrione resistance locus was shown to be a single dominant gene with a 3:1 segregation ratio ($X^2=1.19$, P=0.31). To identify a DNA marker closely linked to the mesotrione resistance gene, bulked segregant analysis (BSA) was adopted. The DNA marker RM3501 was identified on chromosome 2 with a recombinant value of 0.53 to the mesotrione resistance gene. Mst1(t) was located between SSR (simple sequence repeat) markers RM3501 and RM324 with a physical map distance of 10.2 Mb-11.4 Mb on chromosome 2. The band pattern of agarose gel electrophoresis of the SSR marker RM3501 showed the same segregation pattern with respect to mesotrione treatment in 20 Tongil type varieties and a $BC_2F_2$ segregation population derived from a cross between Unkwang (resistant) and Hanareum2 (susceptible). Thus, the RM3501 DNA marker could be used in breeding programs for Marker Assisted Selection in mesotrione resistant rice breeding.

• Journal of Life Science
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• v.17 no.12
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• pp.1701-1708
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• 2007

Seed pelleting is generally conducted in order to save the labor for sowing and thinning by enabling the precision mechanical planting. In the present study, the influence of physical and chemical properties of pelleting solid materials was investigated on carrot seed germination. Among the pelleting solid materials evaluated, dialite, kaolin, and talc showed low bulk density and high porosity. Bentonite and dialite carried high water holding capacities of 184% and 173%, respectively, while calcium carbonate, calcium oxide, and fly ash showed relatively low water holding capacity. The pH of kaolin (6.8) and dialite (7.4) were close to neutral, while limestone (12.8), calcium oxide (13.0), and bentonite (10.0) were highly basic. High electro-conductivity was shown in limestone and calcium oxide. EDS analysis revealed that the main elemental compositions of talc were Si (71.0%) and Mg (29.0%), and those of calcium carbonate were Ca (66.6%), Si (22.9%), and Mg (10.5%). High granulation capacity was observed from talc and the mixture of talc and calcium carbonate. Seeds pelleted with bentonite showed the highest hardness. The dissolving type of the pellet layer after imbibition was split type in talc, limestone, zeolite, and fly ash, melt type in calcium carbonate and calcium oxide, and swell type in bentonite and vermiculite. The shortest dissolving time of pellet layer was observed from calcium carbonate and kaolin. The germination speed $(T_{50})$ was delayed as the size of pelleted seeds increased. The optimum size of pelleting was 19 ratio in carrot.

• Korean Journal of Breeding Science
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• v.43 no.3
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• pp.201-205
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• 2011

'Hangangchal 1' is a new glutinous rice cultivar of second generation Tongil-type with a mid-maturing ecotype that developed by the rice breeding team of Yeongnam Agricultural Research Institute (YARI), RDA. in 2006. This cultivar was derived from a cross between 'Hangangchal', a Tongil-type glutinous cultivar and 'YR8208-20', a high yield potential in 1986/1987 winter season. 'Hangangchal 1' was selected by pedigree and bulk breeding methods from $F_3$ to $F_6$ populations. A promising line, YR10498-8-1-3, was selected and designated as 'Milyang 167' in 1997. The local adaptability test of 'Milyang 167' was carried out at seven locations during 3 years in 1998, 2005, and 2006. It has tolerance to lodging with good canopy architecture as 87cm of culm length. This cultivar is resistant to bacterial blight $K_1$, $K_2$, and $K_3$ race, rice stripe virus, rice dwarf virus, and leaf blast disease. The milled rice endosperm of 'Hangangchal 1' is glutinous and its whiteness was almost similar compared to 'Shinseonchalbyeo'. The yield of milled rice of 'Hangangchal 1' was average 5.97 MT/ha at ordinary cultivation of 9 kg/10a N fertilizer level in local adaptability test. This cultivar would be adaptable to the mid and southern plain of Korea.

• 한국해양학회지
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• v.22 no.3
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• pp.130-142
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• 1987

Sedimentological characteristics of the surface sediments in the southern sea off Cheju Island are described from analyses of bottom sediments. The sediments are subdivided into seven textural classes, muddy sand, slightly gravelly muddy sand, sand, clayey sand, sandy clay, sandymud, silty sand. Sand-size sediments are distributed in the southeastern part and/or around the Island, whereas sandy and muddy sediments are mainly distributed in the central and southern parts of the study area. A small portion of mud patch is located in the southwestern part of the area. According to the textural parameters analysis, sediments in the study area are poorly sorted(av.2.52 ), positive skewed(av.1.61 ), leptokurtic(av.1.74 ), transported by saltation and/or suspension, and roundness of quartz is varied from angular to surrounded, which suggesting that the depositional environment is not simple. The calcium carbonate content is on the average 26.99%, and commonly abundant in sand-size sediments, whereas organic matter content in the bulk sediment is on the average 6.70% and usually dominant in fine-grained sediments.Light minerals consist of quartz(av56.01%),Na-Ca feldspar(av.6.15%),K-feldspar(av.9.22%) and rock fragments(av28.11%).The contect onquartz and K-feldspar increases continuously away from the Cheju Island. As a result of geochemical analysis,concentrations of the elements are as follow:Zn:19.42-43.52 ppm (av.30.67ppm),Mn:50-304 ppm(av139.39ppm),Cr:3.54-10.68ppm(av6.50ppm),Pb:5.52-41.68ppm(av.15.60ppm), Co:7.08-14.68ppm (av.10.78ppm),Ni:19.70-42.42ppm(av.29.57ppm),Cu:3.14-9.12ppm(av.5.14ppm),Fe:0.48-2.08% (av1.22%),Ca:0.32-13.16%(av6.60%),Al:0.06-0.08%(av.0.27%),Mg:0.12-0.76%(av.0.53%)na:0.11-0.51%(av.0.36%) Ag:0.48-4.08ppm(av.1.22ppm).Among these elements,the content of Zn,Cu,Cr,Mn,Fe,Al,Mg,Pb and Na increase toward the southwestern area,while the content of Ca and Ag SHOWS the reversed distribution trend.Such a distribution pattern seems to imply that spatial distrivution of heavy metals is closely related to the variation in grain size. X-ray diffractogram show that the minerals in clay from the southwestern mud patch are illite ,chlorite, kaolinte,feldspar and calcite.The bulk of illite in th mud zone is believed to be originated from Huanghe and Yangytze River.The mud patch in this region contains the diagnostic calcite peak,and the concentration of Ca,ni,Pb,Ag are similar to Huanghe type,which indicates that the greater part of these clay fractions may have been derived from the Huanghe River.

• Journal of Korean Society of Forest Science
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• v.109 no.4
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• pp.382-389
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• 2020

Soil properties in opencast mines are a key factor in reclamation (revegetation) of mining areas. In this study we determined the soil physical and chemical properties of kaolinite tailings, reclaimed areas, and adjacent natural red pine (Pinus densiflora S. et Z.) forests in kaolinite opencast mines in Sancheong-gun, Gyeongsangnam-do. Six sites were chosen for collection of soil samples to determine soil physical and chemical properties at a soil depth of 10 cm. Soil bulk density was significantly higher (P < 0.05) in the kaolinite tailings (1.51 g·cm-3) than in the reclaimed areas (1.19 g·cm-3) and red pine forests (0.93 g·cm-3), whereas air phase in the kaolinite tailings (14.2%) was significantly lower than in the red pine forests (32.6%). Clay content in the red pine forests was significantly higher than in the reclaimed areas (18.7%) or kaolinite tailings (14.8%), whereas soil structural stability index was significantly lower in the reclaimed areas (1.61%) and kaolinite tailings (0.87%) than in the red pine forests (7.75%). Soil pH was significantly higher in the kaolinite tailings (pH 6.68) and reclaimed areas (pH 6.27) than in the red pine forests (pH 5.31). Soil organic carbon and total nitrogen were significantly higher in the red pine forests (C: 36.03 mg·g-1; N: 2.08 mg·g-1) than in the reclaimed areas (C: 5.00 mg·g-1; N: 0.31 mg·g-1) than in the kaolinite tailings (C: 2.12 mg·g-1; N: 0.07 mg g-1). The amount of available phosphorus was not significantly different among the three treatments. The concentration of exchangeable potassium was significantly lower in the kaolinite tailings (0.08 cmolc·kg-1) than in the reclaimed areas (0.21 cmolc·kg-1) and red pine forests (0.30 cmolc·kg-1). These results indicate that, because of high soil bulk density and low soil organic carbon, total nitrogen, available phosphorus, and exchangeable potassium in kaolinite tailings and reclaimed mining areas, soil nutrient management is needed in order to reclaim the vegetation in these type of areas.

• Journal of the Korean Wood Science and Technology
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• v.43 no.3
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• pp.400-409
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• 2015

This study examined the plant growth and development characteristics of leafy vegetables on the hydroponic substrates of waste wood chips, radiate pine chips, and mat type of waste wood chips. The bulk density of waste wood chips and radiata pine chips were $0.2g/cm^3$ and $0.16g/cm^3$, respectively. The moisture retention properties of both the radiata pine chips and waste wood chips were found to be similar but not better than those of the control rock wool and coco peat hydroponic substrates. The moisture retention property of the mat type was found to be the lowest. The chemical analysis of waste wood hydroponic substrates (w/v) was as follows.; The pH was 6.59, electric conductivity was 6.76 dS/m, total nitrogen content was 0.5%, C/N ratio was 113%, phosphorus was 10.1 ppm, potassium was 77 ppm, calcium was 531 ppm, magnesium was 49 ppm, and sodium was 96 ppm. The results from the radiata pine chemical analysis showed that it had a pH of 5.29, electric conductivity of 4.49 dS/m, total nitrogen content of 0.32%, C/N ratio of 180%, phosphorus of 6.4 ppm, potassium of 83 ppm, calcium of 97 ppm, magnesium of 29 ppm, and sodium of 59 ppm. Except for the plants grown in mat type, the developmental characteristics of the plants grown in rock wool and coco peat hydroponic substrates were similar. Based on the results of the experiment, waste wood resources may possibly be used as an organic solid medium in place of the existing rock wool and coco peat medium.

• Journal of Korea Port Economic Association
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• v.34 no.4
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• pp.141-160
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• 2018

In this paper, to analyze the perception and response strategy of Korean ship owners on Global Sulphur Cap 2020, examined the IMO environmental regulation status focusing on MARPOL Annex VI regulation about air pollution prevention, technological measures to reduce SOx emission, shipping industry and management status of Korean ship owners. First of all, the questionnaire was conducted for Korean ship owners after selecting the evaluation factors. The purpose of this study was to investigate the difference of the perception and response strategy of Korean ship owners by corporation size and main vessel type using frequency and cross analysis. It is confirmed that various researches on SOx emission reduction have been carried out from various points of view at home and abroad. In this study, existing studies related to technical factors for regulatory response and economics analysis were examined and evaluation factors were selected. As a result of analysis, it is found that large-sized shipping companies are more prepared for regulatory response than small and medium-sized bulk carrier owners. There were similar perception and the direction of response strategy about the impacts by corporation size and main vessel type. In about two years to be implemented in 2020, It is necessary to find an appropriate response strategy based on the support policy of the government and related organizations and the systematic analysis of the ship owners. Through this study, although the difference between the perception and response strategy of the ship owners by corporation size and main vessel type was understood, it was found that there were limitations on specific response strategy and corporate data collection. In future research, we should overcome the limitations of this study and conduct an in-depth study.