• Korean Journal of Soil Science and Fertilizer
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• v.21 no.3
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• pp.296-300
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• 1988

A trial product of monogranular compound fertilizer for sesame under vinyle mulching cultivations was manufactured using the principal sources of urea, diammonium phosphate and muriate of potash in combination with a filler of zeolite and a binder of liquid waste from glutamic acid fermentation. Two field experiments using transparent vinyl mulching for single-crop cultivation and black vinyl mulching for cultivation after wheat and barley cropping were carried out to evalute their effects on sesame and the results obtained were as follows. Plant height and stem diameter of the trial product in sesame plant were higher and better than those of NPK split application and NPK all basic application. As the yield of the trial product was higher and similar to the NPK application plots in transparent and black vinyl mulching treatment respectively, the one time basic application of a developed monogranular compound fertilizer for sesame was possible under vinyl mulching cultivation.

• Applied Chemistry for Engineering
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• v.25 no.3
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• pp.274-280
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• 2014

Polysulfone (PSf) hollow fiber membranes were prepared via the nonsolvent induced phase separation technique. The cosolvent of ${\gamma}$-butyrolactone (GBL) was added to the polymer solution containing a mixture of PSf and N,N-dimethylacetamide (DMAc). Water was utilized as a precipitation nonsolvent. The morphology of prepared membranes was investigated using a field emission scanning electron microscopy. The fabricated membrane showed a typical asymmetric structure such as the dense layer on the porous support layer by the addition of GBL to the polymer solution. As the concentration of GBL increased, the asymmetric porous structure was shown to be more intensified. It was thought that the added GBL played a role of enhancing the liquid-liquid phase separation of the polymer solution, since the cosolvent of GBL might change the thermodynamic solubility parameter of the doping solution. Permeation properties through the prepared hollow fiber membranes were characterized by measuring the pure water flux and the solute rejection using $0.05{\mu}m$ polystyrene latex (PSL) beads. Experimental results revealed that the use of PEG as the internal coagulant enhanced the pure water flux up to 130 times compared to the use of EG while the rejection of the PSL beads decreased only 5%.

• Korean Journal of Ecology and Environment
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• v.42 no.1
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• pp.124-133
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• 2009

Effects of substrates on the relative immigration activities (RIAs) of epilithic diatoms were examined in Sum River, a tributary of South Han River, Korea. Two hundreds of tile substrates coated with 5% agar were deposited at seven study stations (30 tiles per site) for one month from March 7 to April 7, 2008. Water sampling, physico-chemical factor measurement, and diatom analysis were performed in the field and laboratory. Over the study, major epilithic diatom species were Nitzschia amphibia, Navicula subminuscula, Cymbella minuta in both the natural and artificial substrates. Two dominant species, Nitzschia amphibia and Cymbella minuta often found at seven stations. Among all observed taxa, Nav. subminuscula and Caloneis silicula showed the highest RIA, with the value over 15 throughout the study. Regarding the algal morphology, the biraphe type species showed higher RIA than any other morph, while they comprised over 55% of total biomass, indicating a density effect. Additionally, a significant relationship between RIA and 20-day deposited substrate (p<0.05) showed in two diatom species, Nitzschia fonticola, Gomphonema quadripunctatum, which showed relatively high RIAs. These results indicate that the relative immigration activities of epilithic diatom species can be influenced by algal density in the water and substrate, nutrients, and deposited time at least 20 days.

• Journal of The Korean Society of Grassland and Forage Science
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• v.15 no.2
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• pp.112-117
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• 1995

A field experiment was canied out to determine the effects of harvest time (grazing, soiling and hay stage) on the grass growth, dry matter (DM) yield, nutritive value, and weed development in reed canarygrass (Phalaris arundinacea L.) pasture. The cultivars of reed canarygrass used in this study were Palaton, Venture, Castor, and Frontier (control). The grass was harvested 3 times at hay stage, 4 times at soiling stage, and 6 times at grazing stage in 1992. The average plant height was 31-41cm at grazing, 47-59cm at soiling, and 76-86cm at hay stage. Similar DM yield was observed in Palaton(12,567 kglha), Venture(l2,435kg), and Frontier(12,762kg), and the yields of 3 cultivars were significantly higher than that of Castor(ll,025kg) (P<0.05). Total yields affected by harvest time were lO,O6 1, 1 1,832, and 14,699 kg/ha at grazing, soiling, and hay stage, respectively(P<0.05). The content of crude protein (CP) was not significantly different among cultivars. CP contents by harvest time were 21.6% at grazing, 19.3% at soiling, and 18.8% at hay stage, regardless of cultivm(P<0.05). The contents of neutral detergent fiber (NDF) and acid detergent fiber (ADF) were similar among cultivars and harvest time. However, slightly higher NDF and ADF contents were found in Frontier. The contents of Ca, P, K, and Mg were not affected by cultivars and harvest time. The appearance of weeds was high in Castor, and low in Frontier. The weeds at grazing stage(33.3-60.0%) were remarkably higher than those at soiling and hay astage (ca 10%). In conclusion, it is suggested that 3-4 times (soiling and hay stage) of harvest was recommended for grass production, nutritive value, and weed control in reed canarygrass pasture, regradless of cultivars of Palation, Venture and Frontier, except Castor.

• Journal of The Korean Society of Grassland and Forage Science
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• v.4 no.2
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• pp.89-97
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• 1983

This experiment was carried out in order to study the effect of seasonal changes and location differences on the productivity of the native reed (Phragmites Communis Trinius). The samples of reed were taken at about 30-days interval from May to October, 1982, on the open field of the reclaimed land, the river bank and the tideland in Chonnam area, and measured the yield, the feed compositions and in vitro dry-matter digestibility(IVD). The results are summarized as follow: 1. Plant height was rapidly heightened in May and June, and the number of leaves rapidly increased from May to August. However, dry matter yield increased until September and gradually decreased thereafter. 2. In general, the content of crude protein and the in vitro dry matter digestibility decreased with ageing, and the content of fiber increased. 3. Considerable difference by location in the chemical composition including $SiO_2$, Ca and P was observed. 4. There was a significant negative correlation (p<0.05) between the content of crude protein and that of crude fiber. There was a significant positive correlation(p<0.05) between the in vitro dry-matter digestibility(IVD) by two-stage method and the content of crude protein, and also was a significant negative correlation(p<0.05) between the content of fiber and that of crude protein.

• Journal of The Korean Society of Grassland and Forage Science
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• v.31 no.3
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• pp.285-294
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• 2011

This study was carried out in the Chungnam National University grassland experimental field from October, 2007 to December, 2009 in order to find out the growth characteristics of the wildflowers, the seasonal anthesis distribution of the wildflowers, and the botanical composition of the wildflowers which were altogether composed of 70% sheep fescue and 30% wildflowers. The experimental species contained 34 species in total to which sheep fescue (fundamental turfgrass), 4 native wildflowers, and 29 introduced wildflowers belonged. At the time of the anthesis of the wildflowers, the average length was 29.9 cm one year later and 38.4 cm two years later. They bloomed out into nine colors, but into one or three colors during August, September, and October. The blooming season leant toward May and June and from August there was lots of difficulty in the wildflower blooming and the maintenance of their consistency. Especially, at the age of two (2009) the color, seasonal distribution, and consistency emerged as problems owing to the reduction of annual wildflowers after winterization. The annual ration of wildflowers, sheep fescue, and weeds came to 25%, 61%, and 14% each one year later (2008) and 22%, 65%, and 13% each two years later (2009). Based on this result, cultivating wildflower grassland in the ratio of 70% (sheep fescue) to 30% (wildflowers) is the proper method not only for maintaining green space by sheep fescue, but also for commanding a fine view of wild flowers.

• Korean Journal of Head & Neck Oncology
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• v.21 no.1
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• pp.3-9
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• 2005

Purpose: In oral tongue cancer, the degree of tumor invasion has a significant effect on the prognosis. We hypothesized that the destruction of extracelluar matrix and neovascularization are related to tumor infiltration mechanism. By studying the the tissues of early stage oral tongue cancer patients, we are intend to clarify the invasion related factors in oral tongue cancer. Material and Methods: To demonstrate the invasion process in early T-stage oral tongue cancer, the expressions of extracellular matrix destruction related molecules(MMP2, MMP9) and neovascularization related molecule(VEGF) were observed by immunohistochemical study. Also, immunohistochemical staining of CD31 was done for quantification of neovascularization. With the experiment showed above, we analyzed relationship between expression of each substances and tumor invasion depth, tumor free survival rates and cervical lymph node metastasis rate in early T-stage oral tongue cancer. Results: The expression rates of MMP2, MMP9, VEGF in 38 early oral cancer patients were 52.6%, 78.9% 52.6%, respectively. Significant correlation was found between the VEGF expression and microvessel density showed by CD31 immunohistochemical staining(p<0.001). VEGF expressions were significantly related with tumor invasion depth(p=0.002). The tumor free survival rate of those patients with VEGF-positive tumors was significantly poorer than in those with VEGF-negative tumors(p=0.019). Conclusion: This results indicate that VEGF is a useful marker for predicting the tumor invasion in patients with early tongue cancer and could be used as a beneficial factors in defining operative field and prognosis.

• Fire Science and Engineering
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• v.26 no.4
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• pp.31-41
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• 2012

This study collected 5,100 cases of gas accident occurred in Korea for 14 years from 1995 to 2008, established Database and based on it, analyzed them by detailed forms and reasons. As the result of analyzing the whole city gas accidents with Poisson analysis, the item of "Careless work-Explosion-Pipeline' showed the highest rate of accidents for the next 5 years. And, "Joint Losening and corrosion-Release-Pipeline" showed the lowest rate of accident. In addition, for the result of analyzing only accidents related to LPG vaporizer, "LPG-Vaporizer-Fire" showed the highest rate of accident and "LPG-Vaporizer-Products Faults" showed the lowest rate of accident. Also, as the result of comparing and analyzing foreign LPG accident accompanied by Jet fire, facility's defect which is liquid outflow cut-off device and heat exchanger's defect were analyzed as the main reason causing jet fire, like the case of Korea, but the number of accidents for the next 5 years was the highest in "LPG-Mechanical-Jet fire" and "LPG-Mechanical-Vapor Cloud" showed the highest rate of accidents. By grafting Poisson distribution theory onto gas accident expecting program of the future, it's expected to suggest consistent standard and be used as the scale which can be used in actual field.

• Fire Science and Engineering
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• v.32 no.3
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• pp.42-50
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• 2018

The effect of sub-grid turbulence and combustion models on the mean flame height in a heptane pool fire according to the Fire Dynamics Simulator (FDS) version (5 and 6) based on Large Eddy Simulation (LES) was examined. The heat release rate for the fire simulation was provided through experiments performed under identical conditions and the predictive performance of the mean flame height according to FDS version was evaluated by a comparison with the existing correlation. As a result, the Smagorinsky and Deardorff turbulence models applied to FDS 5 and 6, respectively, had no significant effects on the mean flow field, flame shape and flame height. On the other hand, the difference in pool fire characteristics including the mean flame height was due mainly to the difference in the mixture fraction and Eddy Dissipation Concept (EDC) combustion models applied to FDS 5 and 6, respectively. Finally, compared to FDS 6, FDS 5 provided the predictive result of a significantly longer flame height and more consistent mean flame height than the existing correlation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3792-3799
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• 2012

The dedusting characteristics of pulse air jet type dedusting system which is widely applied in the industries were identified by utilizing the computational fluid dynamics (CFD) and the dedusting performance in modified shape of dedusting unit was compared in this study. The review on the dedusting air volume, air stream distribution and inflow velocity distribution on each shape of dedusting part showed that the case of installing the nozzle on the blow tube (Case-3) and the case of installing the double intaking tube to the venturi (Case-4 and Case-5) were more excellent than the structure (Case-1) which is widely applied in the field in its amplification effect on the air volume and extension of stream width. The specification of venturi was decided to apply the selected Case-5 for the option of the commercial back filter. It is considered that the dedusting air volume will be maintained in maximum in the case of 50 mm and 90 mm for the diameter of internal and external intaking pipe respectively.