• Journal of Korean Society of Water Science and Technology
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• v.26 no.6
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• pp.53-59
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• 2018

Water pollution is drastically increasing day by day, because of the enhancement in use of livestock, urban sewage detergents and fertilizers. Moreover increase in concentration of phosphorous and nitrogen contained in sewage, leads to green tide problem in the rivers and causes marine pollution. For this problem to solve, several technologies are being researched and developed. Among them, this experiment is a study on Bench-scale STP based on internationally certified sewage treatment equipment by MEPC. 227(64) of IMO. The purpose of this study is to compare the biological treatment efficiency of phosphorus of Bench-scale STP. The ratio of C : N : P was set to 10 : 5 : 3 and 10 : 3 : 1 as the operating conditions. And the operation cycle was set to anoxic(mixed) 70 min - aeration 50 min (70-50), anoxic(mixed) 90 min - aeration 60 min (90-60). As a result, the phosphorous treatment efficiency was 88% at average, and the treatment efficiency was steady at 90-60 better than 70-50. The efficiency of the bench-scale STP has been verified through this experiment and additional experiments are required to derive the optimal operating conditions.

• Textile Coloration and Finishing
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• v.26 no.4
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• pp.331-338
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• 2014

In this research, split-type complex yarn of 20:80, 40:60, 50:50 nylon6/polyester composition ratio was used in order to impose unique sense on split-type complex woven. After treating both split-type complex yarn of each ratio and its produced woven in alkali solution, we got the following results by checking physical properties based on alkali proportion and treatment time. Under the condition of NaOH 20% in this experiment, it took approximately double time 20% loss of weight. The loss of weight became high when polyester proportion of N/P(nylon6/polyester) composition ratio was low, in the same fineness yarn. Even though polyester proportion was low, the loss of weight was low when the fineness was high. N/P division was well processed at about 25% loss of weight under the condition of NaOH 20%, treatment temperature $50^{\circ}C$, and treatment time 60 minutes. The research provides that the loss of weight should be processed around treatment time 24 hours in the case of NaOH concentration 15%, and treatment time 15 hours in the case of NaOH concentration 18%, respectively, in order to achieve N/P woven division ratio of about 70%-80% in industrial fields.

• Journal of the Korean Ceramic Society
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• v.30 no.2
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• pp.85-92
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• 1993

Oxynitride glasses in Na-Ca-Si-O-N system were prepared by melting at 135$0^{\circ}C$ for 2 hours in N2 gas. The effects of Si/Na mole ratio and the various Si3N4 contents were investigated. Stable oxynitride glasses can be obtained up to 9wt.% Si3N4 content in case the Si/Na mole ratio was 2.12 and 1.62, but $\beta$-Si3N4 was precipitated at 9wt.% Si3N4 content in case the Si/Na mole rtio was 1.12. Density (p), chemical durability, hardness (Hv), and fracture toughness (KIC) increased with increasing Si3N4 content. In cae the Si/Na mole ratio was 1.12, the increment of properties was remarkable but hardness and fracture toughness did not increase no longer owing to precipitation of $\beta$-Si3N4.

• Journal of Ginseng Research
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• v.41 no.2
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• pp.195-200
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• 2017

Background: The natural ratios of carbon (C), nitrogen (N), and sulfur (S) stable isotopes can be varied in some specific living organisms owing to various isotopic fractionation processes in nature. Therefore, the analysis of C, N, and S stable isotope ratios in ginseng can provide a feasible method for determining ginseng authenticity depending on the cultivation land and type of fertilizer. Methods: C, N, and S stable isotope composition in 6-yr-old ginseng roots (Jagyeongjong variety) was measured by isotope ratio mass spectrometry. Results: The type of cultivation land and organic fertilizers affected the C, N, and S stable isotope ratio in ginseng (p < 0.05). The ${\delta}^{15}N_{AIR}$ and ${\delta}^{34}S_{VCDT}$ values in ginseng roots more significantly discriminated the cultivation land and type of organic fertilizers in ginseng cultivation than the ${\delta}^{13}C_{VPDB}$ value. The combination of ${\delta}^{13}C_{VPDB}$, ${\delta}^{15}N_{AIR}$, or ${\delta}^{34}S_{VCDT}$ in ginseng, except the combination ${\delta}^{13}C_{VPDB}-^{34}S_{VCDT}$, showed a better discrimination depending on soil type or fertilizer type. Conclusion: This case study provides preliminary results about the variation of C, N, and S isotope composition in ginseng according to the cultivation soil type and organic fertilizer type. Hence, our findings are potentially applicable to evaluate ginseng authenticity depending on cultivation conditions.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.250-251
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• 2009

For the fabrication of a multilevel resist (MLR) based on a very thin amorphous carbon (a-C) layer an $Si_{3}N_{4}$ hard-mask layer, the selective etching of the $Si_{3}N_{4}$ layer using physical-vapor-deposited (PVD) a-C mask was investigated in a dual-frequency superimposed capacitively coupled plasma etcher by varying the following process parameters in $CH_{2}F_{2}/H_{2}/Ar$ plasmas : HF/LF powr ratio ($P_{HF}/P_{LF}$), and $CH_{2}F_{2}$ and $H_2$ flow rates. It was found that infinitely high etch selectivities of the $Si_{3}N_{4}$ layers to the PVD a-C on both the blanket and patterned wafers could be obtained for certain gas flow conditions. The $H_2$ and $CH_{2}F_{2}$ flow ratio was found to play a critical role in determining the process window for infinite $Si_{3}N_{4}$/PVDa-C etch selectivity, due to the change in the degree of polymerization. Etching of ArF PR/BARC/$SiO_x$/PVDa-C/$Si_{3}N_{4}$ MLR structure supported the possibility of using a very thin PVD a-C layer as an etch-mask layer for the $Si_{3}N_{4}$ layer.

• Resources Recycling
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• v.8 no.4
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• pp.39-44
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• 1999

Nightsoil and brewery sludges usually contain a high concentration of organic matters. A composting study using reactors was carried out for the recycle of brewery wastewater sludge and nightsoil treatment sludge, which have been landfilled. A good composting process was obtained with a sludge mixing ratio of 1:1 and injual pH had no effect on temperature increase related to microbial activity. The injtial C/N ratio at approximarely 15 decreased to 13 without the increase in pH.. It was found that agitation of one time a week provided the most effective composting process.

• KSBB Journal
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• v.10 no.2
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• pp.176-182
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• 1995

The environmental and physiological factors affecting the production of exopolysaccharide (Methylan) and Poly-${\beta}$-hydroxybutyrate(PHB) by Methylobacterium organophilum were investigated. The maximum PHB content was obtained at $38^{\circ}C$ whereas maximum polysaccharide concentration was $3.54g/\ell$ at $30^{\circ}C$. Optimum pH was pH 7-8 for PHB production and pH 6-7 for polysaccharide production, respectively. Under the condition of $Mo^{2+}, Mg^{2+} or Mn^{2+}$ limitation with nitrogenlimitation, the PHB accumulation was increased, whereas the polysaccharide production was decreased as compared with that of solenitrogenlimitation. Under the condition of sole K+ limitation, cell growth was significantly inhibited and no polysaccharide was produced. However, the PHB content was as high as 60% of dry cell weight. Effect of C/N ratios (methanol/ammonium) in the feeding solution was examined for the simultaneous production of polysaccharide and PHB. The higher ratio of C/N showed the lower cell growth, higher content of PHB in cells, and higher yield of polysaccharide.

• Korean Journal Plant Pathology
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• v.13 no.1
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• pp.46-56
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• 1997

Based on the principal component analysis (PCA) of Richards' parameter estimates, ginseng field soils were grouped as the principal component 1 (PC1) and the principal component 2 (PC2). The microflora and physico-chemical characteristics of each soil group were compared to elucidate soil environmental factors affecting the disease development of root rot of ginseng seedling. Among 3 soil groups by PC1, there were differences in the populations of total fungi (TF) and Cylindrocarpon plus Fusarium (C+F), and the population ratio of Cylindrocarpon plus Fusarium to total fungi or total bacteria (C+F/TF, C+F/TB) in rhizoplane of ginseng seedlings, the population of total actinomycetes (TA) and the population ratio of total Fusarium to total actinomycetes (Fus/TA) in soil, and soil chemical properties (EC, NO3-N, K, Mn, ect.). Among 4 soil groups by PC2, there were differences in TF, C+F, TB, C+F/TF and C+F/TB in the rhizoplane, Trichoderma plus Gliocladium (T+G) in soil, and P2O5 content in soil. Especially, EC, NO3-N, K, K/Mg and Mn were positively correlated to PC1, and TA was negatively to PC1; however, TF, C+F, TB, C+F/TF and C+F/TB in the rhizoplane were significantly correlated to PC2 positively. On the other hand, microbes in the rhizoplane were not significantly correlated to the stand-missing rate (SMR), although TA and Fe/Mn were negatively correlated, and pH and Ca were positively correlated to SMR.

• Journal of Animal Science and Technology
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• v.61 no.2
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• pp.69-76
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• 2019

Maize which has very high omega-6 fatty acid content has been used as a main feed grain for Hanwoo beef production to increase marbling, and thus omega-6 to omega-3 fatty acids ratio in Hanwoo beef is expected to be biased. To elucidate the current status of omega fatty acids ratio in Hanwoo beef, fatty acid profiles of neutral lipid and phospholipid fraction were analyzed separately using 55 Hanwoo steers' longissimus dorsi muscle slaughtered at Pyeongchang, Korea from Oct. to Nov. 2015. In addition, an association study was conducted to evaluate associations between single nucleotide polymorphism (SNP) markers from references and omega fatty acid profiles in phospholipid of Hanwoo beef samples using analysis of variance (ANOVA). In neutral lipid fraction, composition of saturated and monounsaturated fatty acids was higher and polyunsaturated fatty acids was lower compared to those in phospholipid fraction. The mean n-6/n-3 ratios of Hanwoo were $56.059{\pm}16.180$ and $26.811{\pm}6.668$ in phospholipid and neutral lipid, respectively. There were three SNPs showing statistically significant associations with omega fatty acid content. GA type of rs41919985 in fatty acid synthase (FASN) was significantly associated with the highest amount of C20:5 n-3 (p = 0.031). CC type of rs41729173 in fatty acid-binding protein 4 (FABP4) was significantly associated with the lowest amount of C22:2n-6 (p = 0.047). AG type of rs42187261 in FADS1 was significantly linked to the lowest concentration of C20:4 n-6 (p = 0.044). The total n-6/n-3 ratio of the steer which has all four SNP types in above loci (27.905) was much lower than the mean value of the total n-6/n-3 ratio in phospholipid of the 55 Hanwoo steers ($56.059{\pm}16.180$). It was found that phospholipid and neutral lipid of Hanwoo have very high n-6/n-3 ratios compared to the reported data from different cow breeds. Four SNPs in genes related with fatty acid metabolism showed significant associations with the fatty acid profile of phospholipid and may have potential as SNP markers to select Hanwoo steers in terms of n-6/n-3 balance in the future.

• Korean journal of applied entomology
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• v.24 no.4 s.65
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• pp.173-177
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• 1986

This study was carried out to see what makes the 'dark grey cutworm', Agrotis tokionis Butler, inflict less damage in P.E. film-mulched tobacco fields than in nonmulched ones. In field plot experiment, the damage ratio of tobacco seed lings in mulched plots(m) was reduced by 63% compared with that in non mulched ones(n). The altered environments did not affect the cutworm in mortality, which was confirmed by recovery ratio, location of larvae in soil, and developmental age. But the m/n value and damage ratio in plots of different mulching methods strongly suggest that the P.E. film itself prevent larvae from cutting the plants. Larval mortality was rapidly increased between the end of July and the end of August.