• Magazine of the Korea Concrete Institute
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• v.9 no.2
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• pp.57-62
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• 1997

• Proceedings of the Korean Society of Crop Science Conference
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• 1994.10a
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• pp.7-8
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• 1994

• Journal of Korean Society of Forest Science
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• v.106 no.1
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• pp.19-25
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• 2017

This study was conducted to investigate the effects of nitrogen fertilization on physiological characteristics and growth of Populus sibirica seedlings in a semi-arid area, Mongolia. 2-year-old P. sibirica seedlings were planted in May, 2015 with applications of urea 5 g (N1), 15 g (N2), 30 g (N3) and ammonium sulfate 33 g (NS; same nitrogen amount with N2) to each seedling. Chlorophyll contents were significantly different among treatments in August, but not in June and July. The lower chlorophyll contents in August than those in June and July might be related to leaf senescence. In June and July, net photosynthetic rate was higher in NS and N2 than in the control. Unlike the tendency of photosynthesis, transpiration rate was highest in N2, but lower in NS than in any other nitrogen treatments. Relative growth rate of root collar diameter was significantly higher only in NS than in the control and it of height did not differ among treatments. Leaf area in nitrogen treatments was not significantly different from that in the control. Ammonium sulfate seemed to be more suitable fertilizer than urea for the early growth of P. sibirica seedlings in the study site. However, as the effects of urea and ammonium sulfate on soils and seedlings were different, further studies would be necessary to determine the optimal amount of ammonium sulfate.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.6
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• pp.1027-1035
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• 2000

This study was carried out to investigate the treatability of landfill leachate having high concentration of ammonium nitrogen with/without the circulation of media in pilot-scale($48m^3basis$) process. Total nitrogen removal efficiency was relatively increased in the media added process (influent ; $1.230{\sim}2,000mg{\cdot}l^{-1}$, effluent ; $120{\sim}250mg{\cdot}l^{-1}$) compared with the control process. The difference of nitrogen removal efficiency between these processes may be due to that stable growth of nitrifiers attached to the media could be achieved 99.3% of ammonium-nitrogen removal efficiency(without ; 98.2%) and 88.5% of total nitrogen removal efficiency(without ; 85.8%) were shown in media added process, respectively. Also, optimum BOD/ $NH_4{^+}$-N ratio was relatively decreased in the media process compared with the control process. Sludge settleability, on the other hand. was shown better in media added process than in control process. This outstanding sludge settleability in the media added process indicates the compatibility of media(zeolite) to the microorganism and the possibility of using media of biofilm process.

• The Korean Journal of Ecology
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• v.20 no.1
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• pp.35-41
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• 1997

Effects of cadmium on growth and nitrogen fixation activity of Melilotus suaveolens, a biennial legume plant dominating in the area of poor soil were quantitatively analyzed during the growing period. Cadmium treatments of 10, 30 and 100 ppm resulted in 12, 22 and 35% inhibition of plant height and 14, 25 nd 26% reduction of chlorophyll contents of leaves, respectively. The plant biomass reduced 51, 70 and 89% for leaves, 33, 50 and 59% for stems, and 42, 52 and 70% for roots, respectively by 10, 30 and 100 ppm Cd treatments. Cadmium contents of roots treated with 10, 30 and 100 ppm Cd were 62, 112 and 183 folds higher than that of the control, respectively. Cadmium contents of stems were about 1/2.2 of those of roots, but leaves contained only 1/27.8 of those of roots. Cadmium treatments resulted in increase of T/R ratios and decrease of F/C ratios significantly in the later growth period. Nodule formation was reduced to 8% in 42 days by the treatment of 100 ppm Cd. Specific nitrogen fixation activity of nodules attained 61.0, 24.0, 1.6 and 0.7 mol $C_2H_4{\cdot}g$ fr wt $nodule^{-1}{\cdot}h^{-1}$ on 42nd day, respectively for 0, 10. 30 and 100 ppm of Cd treatments. Total amount of nitrogen fixation per plant reduced by 73, 98 and 99% with the treatments of 10, 30 and 100 ppm Cd.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.9 no.2
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• pp.72-80
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• 2006

This study was conducted to evaluate the influence of dried swine excrement on the germination of Pinus thunbergii seeds, the growth response of seedlings of Pinus thunbergii and the uptaken of nitrogen and phosphorous by seedlings of Pinus thunbergii. The germination rate of seeds of Pinus thunbergii tends to decrease according to the increasing of application amount of dried swine excrement and the application amounts of dried swine excrement which is more than 3%(w/w %) makes the rate of germination to much more decreased. Contents of nitrogen and phosphorus are much higher in a way that the dried swine excrement was treated in nursery soil. 179 days after seeds of Pinus thunbergii were sowed, nitrogen contents in soil was decreased more than 70% and phosphorus was decreased 20 to 45%. Growth response of Pinus thunbergii was much higher in treatment of dried swine excrement than in control. But growth response was not affected by increasing of application amounts of dried swine excrement. Growth response of Pinus thunbergii was the highest in 2%(w/w %) application but its growth response was decreased in treatment more than 3% (w/w %) of dried swine excrement.

• Microbiology and Biotechnology Letters
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• v.28 no.6
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• pp.349-354
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• 2000

Culture conditions and nitrogen sources were optimized for production of erythritol, a natural sweetener, by Candida magnoliae M26. The optimal culture conditions were found to be culture temperature of $28^{\circ}C$, initial pH of 7, aeration of 1 vvm and agitation speed of 500 rpm in a 2.5 1 jar-fermentor. Glucose was chosen as the best carbon cource bsed on cell growth and erythritol productivity. Kight steep water(LSW) and corn steep liquor (CSL) which are by-products in starch processing from corn were tested as a nitrogen source substitute for yeast extract. The use of either LSW or CSL did not change the fermentation performance. The experimental results using LSW and CSL showed 1.5 times higher in cell growth and almost the same value in erythritol productivity com-pared with the control fermentation using yeast extract as a nitrogen source. These results suggested that either LSW of CSL could be used as a nitrogen source in a large-scale fermentation for erythritol production.

• Journal of Applied Biological Chemistry
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• v.48 no.4
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• pp.187-192
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• 2005

Influence of herbicide oxadiazon on soil microbial activity and nitrogen dynamics was evaluated. Soil samples were treated with oxadiazon at field and tenfold field rates and incubated. Organic amendment was added as an additional substrate for soil microorganisms. Tenfold field rate oxadiazon stimulated substrate-induced respiration (SIR) and dehydrogenase activity (DHA) in amended soil as compared to unamended soil and control treatment. Soil urease activity was not affected by oxadiazon treatment. In both amended and unamended soils, treatment of the herbicide at higher rate had not significant influence on $NH_4$-N and $NO_3$-N concentrations. Higher dose of oxadiazon was degraded in both soils, but dissipation rate in amended soil was higher than unamended soil, with half-lives ($t_{1/2}$) of 23.1 and 138.6 days, respectively. Recommended field rate did not affect microbial activity and nitrogen dynamics in soil ecosystem. Results showed influence of oxadiazon on cycling processes of nitrogen in soil was not significant however its effect on microbial activity was a tendency depending on addition of organic amendment to soil.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.6
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• pp.932-936
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• 1996

Scallop, Pectinopecten yessoenis(Jay), cultivated in the cold east coast of Kwangwon region, Korea, is expected be to produced about 50, 000 tons in the year 2000. Scallop, first of all should be exuviated to process for new goods. In this study, vacuum and nitrogen packagings were applied to extend the shelf-life of exuviated scallop boiled with steam for 10 min. Vacuum and nitrogen packagings retarded the decrease in pH, whereas inhibited the production of $NH_2-N, $ VBN, TMA, and TBA of exuviated scallop stored at $5^{\circ}C.$ They also inhibited the microbial growth. But, there was no significant difference in the bacteriostatic effects between both packaging methods. The estimated shelf-lives of boiled and exuviated scallops for control, vacuum, and nitrogen packagings were about 30, 36, and 36 days, respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.10 no.5
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• pp.455-459
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• 1997

Fifteen intact male Jamunapari goats, average body weight $22.0{\pm}1.18kg$ were divided into three groups of 5 animals in each to investigate the effects of feeding leucaena on energy retention and distribution of retained energy. Leucaena leaves and twigs provided 0%, 25% and 50% of CP in the rations of animals in $L_1$ (control), $L_2$ and $L_3$ groups, respectively. Energy balances were determined in an open circuit respiration chamber from gaseous exchange and nitrogen carbon balances. Energy retentions calculated from gaseous exchange data were 181.6, 190.0 and 172.8 kJ/kg $W^{0.75}/d$ and from carbon-nitrogen balances were 178.2, 199.5 and 171.1 kJ/kg $W^{0.75}/d$ in $L_1$, $L_2$ and $L_3$ groups, respectively. No significant difference was observed among the groups in both the methods. The retention of nitrogen and energy in the form of protein was similar in different treatment groups. Similarly, no significant effect was observed on energy retention in the form of fat and total energy retention due to incorporation of leucaena in the diets.