• 한국자동차공학회논문집
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• 제3권2호
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• pp.95-101
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• 1995

Experiments have been conducted to investigate the characteristics of formaldehyde and nitrous oxide formation from the catalytic reaction of methane. Catalysts used in the experiment were Pd. Pd/Pt/Rh loaded on ${\gamma}-Al_2O_3$ and ${\gamma}-Al_2O_3-La_2O_3$ monolith. In the catalytic reaction of methane. as the concentration of NO, $O_2$ and $CH_4$ increased, the formaldehyde emission was increased. The concentration of $N_2O$ increased as NO and CO increased. It was also found that the formaldehyde emission was produced by the gas reaction of methane in high temperature above 950K.

• Journal of Microbiology and Biotechnology
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• 제21권9호
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• pp.988-994
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• 2011

A significant amount of nitrous oxide ($N_2O$), which is one of the serious greenhouse gases, is emitted from nitrification and denitrification of wastewater. Batch wastewater nitrifications with enriched nitrifiers were carried out under oxygen-limited condition with synthetic (without organic carbon) and real wastewater (with organic carbon) in order to find out the effect of ammonium concentration on $N_2O$ emission. Cumulated $N_2O$-N emission reached 3.0, 5.7, 6.2, and 13.5 mg from 0.4 l of the synthetic wastewater with 50, 100, 200, and 500 mg/l ${NH_4}^+$-N, respectively, and 1.0 mg from the real wastewater with 125 mg/l ${NH_4}^+$-N. The results indicate that $N_2O$ emission increased with ammonium concentration and the load. The ammonium removal rate and nitrite concentration also increased $N_2O$ emission. Comparative analysis of $N_2O$ emission from synthetic and real wastewaters revealed that wastewater nitrification under oxygen-limited condition emitted more $N_2O$ than that of heterotrophic denitrification. Summarizing the results, it can be concluded that denitrification by autotrophic nitrifiers contributes significantly to the $N_2O$ emission from wastewater nitrification.

• Journal of Advanced Marine Engineering and Technology
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• 제38권9호
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• pp.1045-1050
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• 2014

아산화질소($N_2O$, Nitrous Oxide)는 이산화탄소($CO_2$, Carbon Oxide), 메탄($CH_4$, Metane)이어 세 번째로 지구온난화에 기여하는 물질로 알려져 있다. $N_2O$의 지구온난화 계수는 대기 중에서 안정하고, 성층권에서 광분해 된 후 이차적인 오염의 원인이 되기 때문에 $CO_2$의 310배에 이른다. $N_2O$의 생성에 대한 조사는 보일러와 같은 연속적인 연소를 갖는 동력원에 대하여 몇몇의 연구자들에 의한 보고가 있었다. 하지만, 디젤엔진에 있어서 연료의 성분이 $N_2O$ 배출에 미치는 영향에 대한 조사는 실시되어지지 않은 상태이다. 그러므로 본 연구에서는 디젤엔진에서 연료 중에 질소와 황 농도에 의해 변화되는 $N_2O$ 배출율에 대하여 조사하였다. 실험에 사용한 엔진은 12kW/2400rpm의 4행정 직접분사식 디젤엔진이고, 실험엔진의 운전조건은 75% 부하에서 이루어졌다. 연료 중의 질소와 황 농도는 Pyridine, Indole, Quinoline, Pyrrol, Propionitrile, Di-tert-butyl-disulfide의 6 종류 첨가제를 사용하여 증가시켰다. 결과에 의하면, 질소성분 0.3% 이하를 갖는 디젤연료는 첨가제의 종류와 농도와 관계없이 $N_2O$ 배출률에 영향을 미치지 않았다. 하지만, 연료 중 황 첨가제의 증가는 배기가스 중의 $N_2O$ 농도를 증가시켰다.

• 한국토양비료학회지
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• 제50권6호
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• pp.530-537
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• 2017

Composted animal manure added for improving soil quality and enhancing crop productivity can lead to greenhouse gas emissions such as nitrous oxide ($N_2O$) by processes of nitrification and denitrification. In addition, the amount of $N_2O$ emission from composted manure amended soils can vary greatly with composted manure type or different soil type. Therefore, the influence of cattle composted manure on $N_2O$ emissions was evaluated during growth of sweet potato (Ipomoea batatas). The treatments included control, conventional fertilization (CF), and CF + cattle composted manure (CCM) $10Mg\;ha^{-1}$ were applied in the spring. $N_2O$ emissions were significantly affected by composted manure and chemical fertilizer and the CCM had greater N2O emissions compared with other treatments. The majority of $N_2O$ emissions occurred shortly after composted manure and chemical fertilizer application compared with the rest of the growing seasons for all treatments. Also, $N_2O$ flux was associated with water-filled pore space (WFPS) at all treatments. On average of $N_2O$ emission accumulation, the CCM was 1.5 times greater than control treatment while there was no difference between CF and control.

• Asian-Australasian Journal of Animal Sciences
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• 제18권6호
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• pp.873-878
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• 2005

Emissions of nitrous oxide (N$_2$O) and methane (CH$_4$) from poultry enteric fermentation were investigated using a respiration chamber. Birds were placed in a respiration chamber for certain intervals during their growing period or for the whole life cycle. The accumulated gas inside the chamber was sampled and analyzed for N$_2$O and CH$_4$ production. A curve for gas production during a life cycle was fitted. The calculated area under the curve estimated the emission factor of poultry enteric fermentation on a life cycle basis (mg bird$^{-1}$ life cycle$^{-1}$). This method can be used to estimate CH$_4$ or N$_2$O emissions from different types of avian species taking into account factors such as diet, season or thermal effects. The CH$_4$/N$_2$O emission factors estimated for commercial broiler chickens, Taiwan country chickens and White Roman Geese were 15.87/0.03, 84.8/16.4 and 1,500/49 (mg bird$^{-1}$ life cycle$^{-1}$), respectively, while the calculated CH$_4$/N$_2$O emission from enteric fermentations were 3.03/0.006, 14.73/2.84 and 9.5/0.31 (Mg year$^{-1}$), respectively in Taiwan in the year of 2000. The described method is applicable to most poultry species and the reported emission factors were applicable to meat type poultry only.

• 한국토양비료학회지
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• 제46권6호
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• pp.570-574
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• 2013

This study was conducted to assess $N_2O$ emissions in agricultural soils of Korea under the 1996 IPCC (Intergovernmental Panel on Climate Change) methodology. $N_2O$ emissions in agricultural soils were calculated the sum of direct emission and indirect emission by the N sources and emissions by field burning of crop residues. $N_2O$ emission was highest in animal manure as 1,547 $CO_2$-eq Gg. Indirect emissions by atmospheric deposition and leaching and runoff were 1,463 and 1,753 $CO_2$-eq Gg, respectively. $N_2O$ emission by field burning of crop residues was highest in pepper due to the residue/crop ratio and field burning ratio.

• 한국지하수토양환경학회지:지하수토양환경
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• 제22권6호
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• pp.22-28
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• 2017

The accuracy of analytical results in response to the use of different additives ($NH_4Cl$, KCl, $LaCl_3$) and oxidant gases was evaluated and compared by using Atomic Absorption Spectrometry (AAS). Identification of spectroscopic interferences and possible improvements in Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) analysis were also discussed. The average accuracies of total chromium using Certified Reference Materials (CRMs) were found to be 72.1~94.2% in air/acetylene flame condition by AAS, and they were improved to 100.5~110.5% when the oxidants was changed to nitrous oxide rather than adding the additives. The field samples showed similar trends to CRMs, but chromium concentrations were highly variable depending on analytical conditions. The average accuracies using CRMs were estimated to be 89.3~166.1% by ICP-AES, and improved to below 121.7% after eliminating iron interference. Field samples with low chromium and high iron concentration were measured to be > 30% lower in total chromium concentrations by ICP-AES than AAS in nitrous oxide/acetylene flame. Total chromium concentrations in soil could be analyzed with better accuracy under nitrous oxide/acetylene flame by AAS because it was more effective to increase the temperature of the flame than to eliminate the chemical interference for maximizing atomization of chromium. When using ICP-AES, interference substances, total chromium levels, and analytical conditions should be also considered.

• 한국토양비료학회지
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• 제47권6호
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• pp.598-603
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• 2014

The level of nitrous oxide ($N_2O$), a long-lived greenhouse gas, in atmosphere has increased mainly due to anthropogenic sources, especially application of nitrogen fertilizers. Quantifying $N_2O$ emission in the agricultural field is essential to develop National inventories of greenhouse gases (GHGs) emission. The objective of this study was to develop emission factor to estimate direct $N_2O$ emission from agricultural field by measuring $N_2O$ emissions in the red pepper cultivating field from 2010 to 2012. Emission factor of $N_2O$ calculated from accumulated $N_2O$ emission, nitrogen fertilization rate, and background $N_2O$ emission was $0.0086{\pm}0.00043kg$ $N_2O-N\;kg^{-1}$ N resulted from three year experiment of the research sites. More extensive studies need to be conducted to develop $N_2O$ emission factors for other upland crops in the various regions of Korea because $N_2O$ emission is influenced by many factors including climate characteristics, soil properties, and agricultural practices.

• 한국토양비료학회지
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• 제47권1호
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• pp.59-65
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• 2014

Generally, nitrogen (N) fertilization higher than the recommended dose is applied during vegetable cultivation for increasing in productivity. However, excessive N application rate beyond plant requirement could cause adverse environmental impact such as nitrate leaching and nitrous oxide emission. In this experiment, the impacts of N fertilization was studied on nitrous oxide ($N_2O$) emission to standardize the optimum fertilization level for minimizing of $N_2O$ emission as well as most of the crop productivity. Herein, we assessed the $N_2O$ emission in the flat upland soil which was cultivated with different N application rates on red pepper for 3 years (2010~2012). $N_2O$ emission was measured in chemical N fertilizer amounts 0 (N 0), 95 (N 0.5), 190 (N 1.0), $380(N_2.0)kgha^{-1}$ by using the abnormal shape chamber closed repeating three times. In average for 3 years, the total $N_2O$ emissions of each treatment in field of soybean were 2.110 (N 0), 3.165 (N 0.5), 5.039 (N 1.0), and $7.228(N_2.0)kgN_2Oha^{-1}yr^{-1}$, respectively. And then the primary regression between nitrogen fertilizer amount and the total $N_2O$ emission was showed as y = 0.0138x + 2.0942 ($r^2=0.9885$), and an average of the emission factor was $EF_1$ 0.0148(0.0118~0.0191) $N_2O-NkgN^{-1}kg^{-1}$ from 2010 to 2012. The result was a little higher than the emission default of the IPCC 1996 Guideline ($EF_1$ 0.0125) when the results are converted into $N_2O$ emission factor.

• 한국토양비료학회지
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• 제48권3호
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• pp.163-169
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• 2015

The level of nitrous oxide ($N_2O$), a long-lived greenhouse gas, in atmosphere has increased mainly due to anthropogenic sources, especially application of nitrogen fertilizers. Quantifying $N_2O$ emission in the agricultural field is essential to develop national inventories of greenhouse gases (GHGs) emission. The objective of this study was to develop an emission factor to estimate the direct $N_2O$ emission from an agricultural field cultivated with the Chinese cabbage during autumn season in 2010-2012. Emission factor of $N_2O$ calculated over three years experiment using accumulated $N_2O$ emission, nitrogen fertilization rate, and background $N_2O$ emission was $0.0058{\pm}0.00254kg\;N_2O-N\;kg^{-1}\;N$. More extensive studies need to be conducted to develop $N_2O$ emission factors for other upland crops in the various regions of Korea because $N_2O$ emission is influenced by many factors including climate characteristics, soil properties, and agricultural practices as well as crop species.