• Korean Journal of Soil Science and Fertilizer
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• v.14 no.1
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• pp.31-36
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• 1981

This pot experiment was conducted to find out the optimal fertilization ratio of the anions (N : S : P) in various soil conditions. Soil samples were collected from uncultivated mountains and hills where development for grasslands is under consideration. The optimum ratios were computed by the $Hom{\grave{e}}s$ systematic variation technique. The results were summarized as follows : 1. The optimum fertilization ratios of the anions (N : S : P) for the high yields of grass - clover mixed sward at various areas were obtained (Table 5). 2. The grass yields in mixed sward were increased by the increase of specific soil characteristics, CEC, OM, T-N, avail-$P_2O_5$. However. it was not recognizable by the contents of the cations, the base saturation, and the pH. 3. The relatively high yields of clover were positively related to the Ca and Mg contents in soils, and it was a factor of the increased total yields of mixed sward. 4. The relatively high optimum fertilization ratios of S in volcanic ash soil in the Cheju district and P in sediment lithosol in Daegu should be taken into account in determing the fertilization rate for high yield of clover in mixed sward.

• Journal of Aquaculture
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• v.10 no.3
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• pp.335-346
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• 1997

Denitrification is one of the important processes of removing nitrate from in recirculating aquaculture systems. And this process is affected by many factors such as external organic carbon sources, hydraulic retention time (HRT), COD/NO3--N (C:N) ratio, etc. However, not many studies were done for the optimum conditions of denitrification in the recirculation system for aquaculture. Therefore, this study was conducted to find out the optimum removal condition of NO3--N using submerged denitrification biofilter. The combinations of two external organic carbon sources (glucose and methanol), two HRT (4 and 8-hour) and four differnent C : N ratios (3, 4, 5, 6) were tested. The removal efficiencies of NO3--N and total inorganic nitrogen (TIM) at 8-hour HRT were better than those at 4-hour's (P<0.05). The maximum removal efficiency of NO3--N by methanol (97.8%) was achieved at HRT and C : N ratio were 8-hour and 4.0 respectively. The efficiencies of methanol for the removal of NO3--N and TIN were always better than those of glucose (P<0.05). The maximum removal efficiencies of total inorgainc nitrogen (TIN) were gained at C : N ration of 5.0. The maximum removel efficiencies of TIN using methanol and glucose were 96.9% and 71.5% respectively. Anaerobic condition which is necessary for denitrification process was not made until the 8-hour HRT and higher C : N ratio (5.0). Removal of NO3--N at 4-hour HRT and C : N ration lower than 5.0 were inhibited by oxygen and/or low quantity of external organic carbon. Removal efficiencies of NO3--N were also inhibited by high C : N (6.0) ratio when HRT was 8-hour.

• Journal of Environmental Health Sciences
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• v.22 no.4
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• pp.82-90
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• 1996

This study was performed to find the optimum mixing ratio of paper waste in composting of mixture of swine feces and newspaper. Using the experimental setting of aeration rate which was found in the experiment carried out priorly, and moisture contents reported in other literature, just the initial C:N ratios were differentiated by mixing different amount of newspaper with the same amount of swine feces. This study was carried out by operating 4 experimental cornposting reactors of bench scale for 3 weeks. The followings are the conclusions that were derived from this study. 1. During composting reaction, the C:N ratio of each cornposter was decreased. Degree of decrease was in order of run 3, run 2, run 4, and run 1 of which initial C:N ratio was 30, 25, 35, and 20 respectively. All of the final composts were found to be completed composting reaction. 2. Ash contents of each reactor increased rapidly in order of run 3, run 2, run 4, and run 1. The absolute values of quadratic effect coefficients of each second order regression function was 0.059, 0.038, 0.032, and 0.030 respectively. Ash contents evolution trend had a linear correlation with the C:N ratio trend. (r=-0.96932, p<0.05) 3. The range of highest temperatures reached during composting was 47.2-53.5$\circ$C. Those were not significantly different from one another. Thermophilic temperatures were maintained in the range of 48-108 hours. 4. Contents of heavy metal detected in the final compost were lower than those of Korean and European standards. 5. Concentration range of Nitrogen in the final compost was 1.11-2.27%, and that of phosphorus was 8.40-10.70 mg/kg. 6. The optimum C:N ratio which has been proposed without the consideration of types of bulking agents should be re-examined. Biodegradabilities of each bulking agents was thought to be important factor when determining the optimum initial C:N ratio for cornposting.

• Bulletin of the Korean Chemical Society
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• v.10 no.1
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• pp.47-50
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• 1989

The methanolysis reactions of phenylacetyl chlorides have been investigated in methanol-acetonitrile mixtures at temperatures ranging - $15.0-0.0^{\circ}C.$ Substituent and solvent effects on the rate supported an associative $S_N2$ mechanism for the solvolysis. Activation parameters indicated that the reaction is entropy controlled, while the a/s ratios of the Taft's solvactochromic correlation proved to be remarkably constant with a typical value of 0.50 that is consistent for the reactions proceeding by a typical $S_N2$ path.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.405-410
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• 1999

This study was performed to find the recycling performance and to provide design data during recycle solid composting system to reduce bulking agent cost, Dairy manure amended with rice hulls and recycled compost was composted in a laboratory -scale vessel by continuous aeration for 10 days. The temperature and ammonia emission variations according to the ratios of bulking agents during the primary aeration stage were surveyed. Also, the influence of fresh compost quality on the recycling performance were anlayzed. While recycled composting system were operatured. The temperature in compost was maintained in the range of 40∼60$^{\circ}C$ needed for biodegradation and death of pathogenic organisms, but the ammonia emission was different by the ratios of recycled compost. The ammonia emission increased due to the low C/N ratio(17.6), high pH value(8.1) of the recycled compost.

• Journal of the Korean Chemical Society
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• v.26 no.4
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• pp.235-246
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• 1982

The free radical polymerization and copolymerization of N-acetyl ${\alpha}$-aminoacrylic acid were investigated. From the result of kinetic investigation of N-acetyl ${\alpha}$-aminoacrylic acid in DMF at $60^{\circ}C$, a rate equation of $R_p$ = $k_p[M]^{0.97}[I]^{0.59}$ was obtained. The overall activation energy for the polymerization was found to be 25.2 kcal/mole. Copolymerization of N-acetyl ${\alpha}$-aminoacrylic acid with acrylic acid and styrene was carried out for the determination of monomer reactivity ratios. The monomer reactivity ratios for the monomer pairs determined at 70.0{\pm}0.1^{\circ}C$ using benzoyl peroxide as an initiator are; $r_1$(N-acetyl ${\alpha}$-aminoacrylic acid) = 0.49, $r_2$(acrylic acid) = 1.41, $r_1$(N-acetyl ${\alpha}$-aminoacrylic acid) = 0.44, $r_2$(styrene) = 0.91. The values of Alfrey-Price's Q and e parameters for N-acetyl ${\alpha}$-aminoacrylic acid were calculated to be 0.51 and 0.16 for the both systems. Differential thermal analysis and thermogravimetry showed that acrylic acid copolymers have poorer thermal stability as compared with the homopolymer of N-acetyl ${\alpha}$-aminoacrylic acid.

• 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.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.6
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• pp.527-533
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• 2018

Microorganisms detected in the biofilm not only cause secondary pollution of drinking water such as taste, odor and pathogenic disease but also increase the amount of disinfectant due to microbial regrowth during the transportation of tap water. In this work, the influence of C/N ratio in tap water on the characteristics of biofilm growth was examined. The C/N ratio of the tap water sample was controlled at 100:5, 100:10, 100:20, 100:30, and 100:40 by adding appropriate amounts of dextrose and $(NH_4)_2SO_4$. Of the five C/N ratios, heterotrophic plate counts (HPC) was highest at the ratio of 100:10. Following the initial formation in all the five experimental conditions, natural detachment of the biofilm was observed. Extracellular enzyme activity (EEA) analyses showed that the change of the EEA during the experimental period was similar to that of the HPC, demonstrating a positive correlation between HPC and EEA. For TOC concentration in the tap water sample, approximately 75% of the TOC was consumed in 7 days of the experiment and 96% in 28 days. The TOC appeared to be relatively rapidly consumed at the initial phase of the biofilm growth. Consumption pattern of the ammonia nitrogen was different from the TOC consumption pattern showing the different role of ammonia nitrogen on the growth of biofilm.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.8
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• pp.677-681
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• 2009

$In_xGa_{1-x}N$ alloys with 20-nm-thickness were deposited onto Mg:GaN/AlN/SiC substrates by MOCVD at $800\;^{\circ}C$. TMGa, TMIn and $NH_3$ were used as the precursor of gallium, indium and nitrogen, respectively. The mole ratio of indium in $In_xGa_{1-x}N$ films varied between 0 and 0.2. The energy-band-gaps of the films were obtained from the photoluminescence and cathodoluminescence peaks. The mole ratios of $In_xGa_{1-x}N$ films were calculated by applying Vegard's law to XRD results. The energy-band-gap versus indium composition plot for $In_xGa_{1-x}N$ alloys were well fit with a bowing parameter of 2.27.

• Environmental Engineering Research
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• v.19 no.1
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• pp.67-73
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• 2014

In India, disposal of vegetable market waste along with municipal solid waste in landfills or dumpsites is creating much nuisance in terms of odor nuisance, leachate production, and greenhouse gas emission into the atmosphere. Therefore, vegetable waste with high biodegradable and nutrient content is composted in a 550-L batch scale rotary drum composter to study the degradation process and its compost properties for its potential reuse as high quality compost. A total 150 kg of working volume was fixed for composting studies with two different ratios, trial A (6:3:1) of C/N 24 and trial B (8:1:1) of C/N 30, respectively. A maximum of $63.5^{\circ}C$ and $61.2^{\circ}C$ was observed in trials A and B; an average of $55^{\circ}C$ for more than 5 days, which helped in the degradation of organic matter and reduction of total and fecal coliform. The temperature dropped suddenly after the thermophilic stage in trial B, and leachate was observed due to insufficient amount of bulking agent. Mesophilic bacteria dominated during the initial stages of composting, and reduced considerably during the thermophilic stage. During the thermophilic stage, the rise in spore-forming organisms, including spore-forming bacteria, fungi, actinomycetes and streptomycetes, increased and these were predominant until the end of the composting process. By examination, it was observed that moisture and leachate production had adverse effects on the compost parameters with higher loss of micronutrients and heavy metals.