• Asian-Australasian Journal of Animal Sciences
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• v.16 no.11
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• pp.1583-1591
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• 2003

The influence of varying levels of urea and additives on nitrogen (N) retention and chemical composition of wheat straw was studied. The wheat straw was treated with 4, 6 and 8% urea and ensiled with 1.5, 2 and 2.5% of acetic or formic acid and 2, 4 and 6% of corn steep liquor (CSL) or acidified molasses for 15 days. The N content of wheat straw was significantly different across all treatments. The N content of urea treated wheat straw was increased with the increasing level of urea. The N content was higher in urea treated wheat straw ensiled with acetic or formic acid as compared to urea treated wheat straw ensiled without these organic acids. The N content of urea treated wheat straw was further enhanced when it was ensiled with CSL or acidified molasses. This effect was significant across all levels of urea used to treat the wheat straw. Nitrogen retention in urea treated wheat straw was decreased linearly as the urea level was increased to treat the wheat straw. The N content was increased linearly when higher levels of CSL or acidified molasses were used to ensile the urea treated wheat straw. Most of the N in urea treated wheat straw was held as neutral detergent insoluble N (NDIN). The NDIN content was increased linearly with the increasing levels of urea and additives. The neutral detergent fiber (NDF) contents were higher in urea treated wheat straw ensiled with acetic or formic acid as compared to urea treated wheat straw ensiled without additive. The NDF content further increased in urea treated wheat straw ensiled with CSL and acidified molasses. The entire increase in NDF content was because of fiber bound N. The hemicellulose content of urea treated wheat straw ensiled with CSL or acidified molasses was higher as compared to urea treated wheat straw ensiled with acetic or formic acid. The acid detergent fiber content of urea treated wheat straw ensiled with or without additives remained statistically non-significant. The cellulose contents of wheat straw was linearly reduced when urea level was increased from 4 to 6 and 8% to treat the wheat straw. This effect was further enhanced when urea treated wheat straw was ensiled with different additives. The results of the present study indicated that fermentable carbohydrates might improve the Nitrogen retention and bring the favorable changes in physiochemical nature of wheat straw. However, biological evaluation of urea treated wheat straw ensiled with fermentable carbohydrates is required.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.1
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• pp.78-88
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• 1985

Nitrogen fertilizer effectiveness on rice production was studied to evaluate the different forms and sources. Seven kind of nitrogen fertilizers were applied in two levels, 15 and 30 kg per 10a on Jinjubyeo (Japonica type) in silt loam paddy soil of pot cultivation. The results were summerized as follows; 1. pH in soils was decreased with enhancement of ammonium sulfate application in $NH_4-N$, but it was increased with times after nitric-acid application and PH change in soil was not remarkable when $NO_3-N$ with accessory component was applied. 2. $NH_4-N$ contents in soil were the lowest at 2 weeks after application in N 15kg/10a regardless of different sources of nitrogen fertilizer. $NO_3-N$, in N 30kg/10a, was decreased continuously until 4 weeks, while $NH_4-N$, Urea-N were at minimum during 2-3 weeks. 3. Growth of culm length and straw weight applied with AN (Ammonium Nitrate), AS (Ammonium Sulfate) and urea were superior to the form of nitrate. While NA (Nitric Acid), PN (Potassium Nitrate) and CN (Calcium Nitrate) plot of the $NO_3-N$ was the dominant fertilizers for root elongation. 4. Brown rice yields were increased dominantly by $NH_4-N$ application such as AS or AP than $NO_3-N$ pot. But the yields in case of $NO_3-N$ application CN, PN and NA were decreased. 5. N, P, Mg and Mn content of straw ranked the effectiveness of nitrogen forms as $NH_4-N$, Urea-N and $NH_4-N+NO_3-N$, while K, Ca and $SiO_2$ content of straw in $NO_3-N$ fertilizer plot were high while N, P, Mg, Mn, Fe and Mg were low. 6. Increament of nitrogen absorption in straw was stimulated by enhancement of phosphorous absorption and the growth and yield of rice plant were increased. Absorption of N, P, Ca and Mg was decreased by CN application. Absorption of N, P and Mg also was decreased by $NO_3-N$ application and N, P, Mg or Ca content were seemed to simulated the growth and yield of rice plant. 7. $SiO_2$, Zn and Fe contents of the root at harvest stage were higher than those of the straw. N, P, Mg, Mn, Zn and Fe contents were high in $NH_4-N$ and Urea treatment. While K, ca and $SiO_2$ contents, however, were high in $NO_3-N$ treatment.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.10
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• pp.642-647
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• 2014

For feasible study of opto-electrical application regarding to oxide semiconductor, we implemented the N doped ZnO growth using a atomic layer deposition technique. The p-type ZnO deposition, necessary for ZnO-based optoelectronics, has considered to be very difficulty due to sufficiently deep acceptor location and self-compensating process on doping. Various sources of N such as $N_2$, $NH_3$, NO, and $NO_2$ and deposition techniques have been used to fabricate p-type ZnO. Hall measurement showed that p-type ZnO was prepared in condition with low deposition temperature and dopant concentration. From the evaluation of photoluminescence spectroscopy, we could observe defect formation formed by N dopant. In this paper, we exhibited the electrical and optical properties of N-doped ZnO thin films grown by atomic layer deposition with $NH_3OH$ doping source.

• Bulletin of the Korean Chemical Society
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• v.19 no.12
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• pp.1314-1319
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• 1998

Electronic structures and properties of the organometallic precursors [Me2AlNHR]2 (R =Me, iPr, and tBu) have been calculated by the semiempirical (ASED-MO, MNDO, AM1 and PM3) methods. Optimized structures obtained from the MNDO, AM1, and PM3 calculations indicate that the N-C bond lengths are considerably affected by the change of the R groups bonded to nitrogen, but the bond lengths of the Al-N and Al-C bonds are little affected. This result is useful in explaining the experimental results for the elimination of the R groups bonded to nitrogen, and could serve as a guide in designing an optimum precursor for the AlN thin film formation.

• Journal of The Korean Society of Grassland and Forage Science
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• v.14 no.4
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• pp.271-280
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• 1994

The aim of this experiment was to investigate the effects of fertilizing mineral nitrogen on dry matter yield of Reed canarygrass and also to estimate proper levels of fertilizing nitrogen when uncultivated rice paddy rapidly increased these days, was used for the production if Reed canarygrass. \ulcornerhe results are as follows. 1. Relative dry matter according to cutting frequency was appeared the highest at the 2nd cut for 3 and 4 cutting frequencies, and the 3rd cut for 5 cutting frequency. Those were 43.1, 34.0 and 34.1 % respectively. 2. When using only phosphrous and potassium, the average dry matter per year and ha was between 9.0 and 12.0 tons(3, 4 and 5 cutting frequency) and the highest dry matter was shown at 5 cutting frequency. 3. In accordance to the increase in the fertilization of nitorgen, the yield of dry matter was increased and, when 30 kg/ha/cut of mineral nitrogen was added, the biggest increase rate per added nitrogen for dry matter yield per year compared to that of no fe~tilization of nitrogen was recorded and it was 2.7, 3.3, and 3.4 tons/ ha for 3, 4 and 5 cutting frequencies respectively. 4. The efficiencies of mineral nitrogen on dry matter yield(DM kg/N kg) were the highest when 30kg nitrogen was applied particularly in 3, 4 and 5 cutting frequencies(29.7, 27.2, 22.8 DM kg/N kg). It recorded the highest of all the treatments. The efficiency was actually decreased in higher application of mineral nitrogen. The total nitrogen yield efficiency was the highest in 30kg(0.45kg and 0.48kg at 4 and 5 cutting frequency) and 60kg fertilization/ha/cut (0.46kg at 3 cuting frequency) and the decreased efficiencies appeared at fertilization of higher nitrogen. 5. Economical borden of mineral nitrogen fertilization were between 199.2 and 243.3kglha at 3 cutting frequency, between 253.4 and 295.9kg at 4 cutting frequency and between 302.2 and 361.3kg at 5 cutting frequency. 6. Under the condition of this experiment, the cutting frequency leading the potential production at maximum was 3 cutting frequency. At 3 cutting frequency, the efficiency of nitrogen utilization was higher and 15 or 16 tons of dry matter was obtained which is a level of economical border at fertilization between 200 and 240kglha. It wrs possible to obtain the maximal dry matter yield(l7 tonslha) at fertilization of lower level than 400kgl ha.

• Environmental Engineering Research
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• v.25 no.3
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• pp.274-280
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• 2020

The marine sediment sustains from the anoxic condition due to increased nutrients of external sources. The nutrients are liberated from the sediment, which acts as an internal source. In hypoxic environments, anaerobic respiration results in the formation of several reduced matters, such as N₂ and NH₄⁺, N₂O, Fe²⁺, H₂S, etc. The experimental results have shown that nitrogen and sulfur played an influential, notable role in this biogeochemical cycle with expected chemical reductions and a 'diffusive' release of present nutrient components trapped in pore water inside sediment toward the bulk water. Nitate/ammonium, sulfate/sulfides, and ferrous/ferric irons are found to be the key players in these sediment-waters mutual interactions. Organonitrogen and nitrate in the sediment were likely to be converted to a form of ammonium. Reductive nitrogen is called dissimilatory nitrate reduction to ammonium and denitrification. The steady accumulation in the sediment and surplus increases in the overlying waters of ammonium strongly support this hypothesis as well as a diffusive action of the involved chemical species. Sulfate would serve as an essential electron acceptor so as to form acid volatile sulfides in present of Fe³⁺, which ended up as the Fe²⁺ positively with an aid of the residential microbial community.

• Journal of Environmental Health Sciences
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• v.26 no.3
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• pp.98-102
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• 2000

The aim of this study was to evaluate on the removal effect of total nitrogen in municipal wastewater by decreasing hydraulic retention time(HRT) from 6 hour to 4 hour on CNR process. CNR-A(Cilia Nutrient Removal) is the process combining A2/O process with cilium media of H2L corporation. The removal efficiencies for T-N were 63.1% in A-1 reactor, and 73.5% in A-2 reactor and 77.0% in A-3 reactor. The specific nitrification(g-NH3-N/g-MLVSS.d) of Oxic in CNR-A process was 0.07-0.32. The specific denitrification in Anoxic and the specific nitrification inOxic was higher in HRT 4 hour because of optimum F/M ratio.

• Proceedings of the KWS Conference
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• 1998.05a
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• pp.150-154
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• 1998

The purpose of this paper is to investigate optimum welding conditions of STS 304 thin sheet by GTA welding and control 6 $\delta$--fenite which is harmful in mechanical processing, corrosion problem and can be formed brittle a phase in using long term at high temperature. One series of automatic welds was made using argon plus 10, 20, 30 % nitrogen to ensure a fully austenite deposit. Results obtained were summarized as follows: 1) 6 $\sigma$ferrite content in the weld metals is influenced largely by the nitrogen content. 2) Additions of nitrogen to the shielding gas can significantly reduce the amount of retained delta ferrite and result in an increase in hot cracking. 3) Bead width was increased when Ar + $N_2$ shielding gas was used and travel speed was increased. 4) Ar+$N_2$ shielding gas made weld metal ductile and reduce 6 -$\delta$-ferrite.

• Carbon letters
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• v.7 no.1
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• pp.9-18
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• 2006

Activated carbons were obtained by activating wild cherry stones with different concentrations of phosphoric acid or zinc chloride at different temperatures. The adsorption of $N_2$ at 77 K and of $CO_2$ at 273 K was followed and the data were analyzes by considering different adsorption models. The activated carbons obtained measured high surface area with the most of the surface in all samples located in micropores. Fair agreement was found between the nitrogen surface areas calculated from the BET-, t-, ${\alpha}$- and DR- methods, although the first three are based on surface coverage whereas the latter is based on micropore filling. The carbon dioxide surface areas calculated by the DA equation were smaller than the comparable nitrogen areas. This was ascribed to domination of surface coverage mechanism, the absence of activated diffusion process. Based on this explanation the $CO_2$-surface areas as calculated by DA equation should be taken with great reservation.

• Journal of Korean Society on Water Environment
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• v.21 no.6
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• pp.643-650
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• 2005

In order to treat leachate from aged landfill site effectively, removal of biologically recalcitrant organic matter and denitrification efficiency were evaluated through the combination of $H_2O_2/O_3$ AOP pretreatment process and UASB process. The results can be summarized as follows. In case of leachate having low COD/N ratio from aged landfill site, it is possible to increase available COD for denitrification in nitrate utilizing denitrification and nitrite utilizing denitrification both by enhancing biodegradability of recalcitrant organic matter as applying $H_2O_2/O_3$ AOP to pretreatment process. In this experiment, it is found that available COD for denitrification can be increased to 1.0 and 0.4 g/day, respectively. Comparison has been made between requiring COD and available COD for denitrification in each experimental stages. It is expected that high rate of denitrification can be achieved with leachate from young landfill site because higher amount of available COD for denotrification is present in the leachate than the amount of requiring COD for denitrification. Especially, In leachate from aged landfill site with low COD/N ratio, it can be concluded that denitrification using nitrite nitrogen can enhance overall denitrification performance efficiently because denitrification using nitrite nitrogen requires less amount of carbon source than denitrification using nitrate nitrogen. Comparing the biogas production rate and nitrogen content of biogas under the condition of same amount of nitrate and nitrite addition, biogas production and nitrogen content of biogas are increased during denitrification after $H_2O_2/O_3$ AOP pretreatment process. Therefore, it can be confirmed that COD/N ratio in the leachate is increased. Applying $H_2O_2/O_3$ AOP as pretreatment system of landfill leachate seems to have little economic benefit because it requires additional carbon source to denitrify ammonia nitrogen in leachate coming from aged landfill site. However, it is possible to apply this pretreatment process to leachate from old landfill site in view of AOP process can achieve removal of biologically recalcitrant organic matter and increase of available COD for denitrification simultaneously.