• Journal of Korean Society for Atmospheric Environment
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• v.20 no.6
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• pp.749-758
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• 2004

Nitrous oxide ($N_2$O) has been known as an important trace gas due to the greenhouse gas and the major source of stratospheric oxide of nitrogen (NO). Soil is the major source of $N_2$O in nature. The physicochemical characteristics of soils affect the emission of $N_2$O from soil. These physicochemical parameters are soil moisture, soil temperature, and soil N content. Since these parameters are correlated to the flux of $N_2$O from soil individually and compositely, there still remain many unknowns in the mechanism to produce $N_2$O in soil and the roles of such physicochemical parameters which affect the soil $N_2$O emission. Soil $N_2$O fluxes were measured at different levels in water filled pore space (WFPS), soil temperature and soil N contents from the same amounts of soils which were sampled from agriculturally managed upland field in a depth of ～30 cm at Kunsan. The soil $N_2$O flux measurements were conducted in a laboratory with a closed flux chamber system. The optimum soil moisture and soil temperature were observed at 60% of WFPS and ～13$^{\circ}C$. The soil $N_2$O flux increased as soil N contents increases during the whole experimental hours (up to 48 hours). However, average $N_2$O flux decreased after ～30 hours when organic carbon was mixed with nitrogen in the sample soils. It is suggested that organic carbon could be important for the emission of $N_2$O, and that the ratio of N to C needs to be identified in the process of $N_2$O soil emission.

• 한국연소학회:학술대회논문집
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• 2006.10a
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• pp.128-133
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• 2006

Influence of changing combustor pressure on flame stabilization and nitrogen oxide (NOx) emission in the swirl-stabilized flame with secondary fuel injection was investigated. The combustor pressure was controlled by suction at combustor exit. Pressure index ($P{\ast}=P_{abs}/P_{atm}$), where $P_{abs}$ and $P_{atm}$ indicated the absolute pressure and atmosphere pressure, was controlled in the range of $0.7{\sim}1.3$ for each equivalence ratio conditions. The flammable limits of swirl flames were largely influenced by changing combustor pressure and they showed different tendency compared with laminar flames. Emission index showed maximum value near atmospheric condition and decreased with decreasing pressure index for overall equivalence ratio conditions. R.m.s of pressure fluctuations also showed similar tendency with nitric oxide emission. By injecting secondary fuel into flame zone, the flammable limits were extended significantly. Emission index of nitric oxide and r.m.s. of pressure fluctuations were also controlled by injecting secondary fuel. The swirl flames were somewhat lifted by secondary fuel with high momentum, hence low nitric oxide emission. This NOx reduction technology is applicable to industrial furnaces and air conditioning system by adopting secondary fuel injection.

• YAKHAK HOEJI
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• v.48 no.6
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• pp.309-316
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• 2004

The present investigation was undertaken to find out the anticancer activity of monoterpene compounds. Monoterpenes showed generally the inhibitory effect on the proliferation o f L1210 cancer cells (cytotoxicity). Geraniol was found to exibit the most potent cytotoxic effect on L1210 cells with an IC50 values of $0.67{\mu}g/ml$. On the other hand, geraniol proved to be capable of stimulating the macrophage proliferation (135% of control). When the life prolonging activity of geraniol by daily oral administration of 0.1~10${\mu}g/10{\mu}l/20$ g body weight to Sarcoma 180 bearing ICR mouse was examined, there was also a significant elevation of survival (best result of 134% of control). The contradictory effects of geraniol on the proliferation of L1210 cells and macrophages proved to be accompanied by the coincident alterations of RNS (reactive nitrogen species) related enzymes activities such as inducible nitric oxide synthase (Inos) in macrophages and ROS (reactive oxygen species) related enzymes activities such as superoxide dismutase (SOD) in L1210 cells, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.391-391
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• 2010

The stability enhancement of Znic oxide thin film transistor deposited by PLD-DBD has been reported here using the bias temperature stress test. Znic oxide (ZnO) thin films were deposited on $SiO_2$/Si (100) by pulsed laser deposition method with and without dielectric barrier discharge (DBD) method. The DBD is the efficient method to adopt the nitrogen ions into the thin films. The TFT characteristics of ZnO TFTs with and without Nirogen (N) doping show similar results with $I_{on/off}$ of $10^5{\sim}10^6$. However. the bias temperature stress (BTS) test of N-doped ZnO TFT with DBD shows higher stability than that of ZnO TFT.

• Journal of Ecology and Environment
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• v.29 no.3
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• pp.305-321
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• 2006

Atmospheric Acid Deposition: Nitrogen Saturation of Forests: Volume weighted annual average wet deposition of nitroge at 33 sites in Korea during 1999-2004 ranged 7.28 to $21.05kgN{\cdot}ha^{-1}{\cdot}yr^{-1}$ with average $12.78kgN{\cdot}ha^{-1}{\cdot}yr^{-1}$, which values are similar level with nitrogen deposition of Europe and North America. The temperate forests that suffered long-term high atmospheric nitrogen deposition are gradually saturated with nitrogen. Such nitrogen saturated forest watersheds usually leach nitrate ion ($NO_3^-$) in stream water and soil solution. It may be likely that Korean forest ecosystems are saturated by much nitrogen deposition. In leaves with nitrogen saturation ratios of N/P, N/K and N/Mg are so enhanced that mineral nutrient system is disturbed, suffered easily frost damage and blight disease, reduced fine-root vitality and mycorrhizal activity. Consequently nitrogen saturated forests decrease primary productivity and finally become forest decline. Futhermore understory species are replaced the nitrophobous species by the nitrophilous one. In soil with nitrogen saturation uptake of methane ($CH_4$) is reduced and emission of nitrogen monoxide (NO) and nitrous oxide ($N_{2}O$) are increased, which gases are greenhouse gas accelerating global warming.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.2
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• pp.19-38
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• 2023

Nitrous oxide, one of the six greenhouse gases from Kyoto protocol, is known to be emitted in biological nitrification and denitrification reactions at wastewater treatment plant. In this study, EQPS which is a computer program that can simulate nitrous oxide gas emission amount at wastewater treatment plants is used. The MLE process which treats wastewater from combined sewer is studied. Operational variables which are MLR, water temperature at reactor and primary clarifier by-pass percentage are changed to define the condition which produces the least amount of nitrous oxide gas. 200 % of MLR, 20 ℃ of water temperature at bioreactor and 15 % of primary clarifier by-pass percentage are shown the least nitrous oxide emission factor. Also, it is found that the deep aeration tank produces less amount of nitrous oxide gas since less air is required to meet oxygen demand in this type of aeration tank.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.2
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• pp.86-90
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• 2012

The gaseous product of nitrogen cycle, nitrous oxide ($N_2O$) is a potent greenhouse gas whose Global Warming Potential (GWP) is about 300 times greater than $CO_2$. The dynamics of $N_2O$ emission are controlled by such environments and soil conditions. The main aim of this study is to investigate variations of $N_2O$ emission and its controlling factors with different land-use patterns in Haean basin. A forest, a radish field and a rice paddy were selected as three different land-use patterns. Their $N_2O$ emissions were measured every month during a growing season. We also collected soil samples with seasons and analyzed soil characteristics including inorganic nitrogen content. $N_2O$ emission was greatest at the radish field likely due to anthropogenic nitrogen addition by fertilization. Soils of forest and rice paddy also contained inorganic nitrogen originated from organic matter. However, the spatial variation was great and it looks that nitrogen cycle and $N_2O$ production were slower than that of radish field. Intensive observation and control of fertilization would be requiredto adjust $N_2O$ emission from agriculture soils.

• Applied Chemistry for Engineering
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• v.19 no.6
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• pp.624-628
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• 2008

Nitrous oxide ($N_2O$), known as one of the major greenhouse gases, is an important component of the earth's atmosphere, and gives rise to precursor of acid rain and photochemical smog. For the removal of $N_2O$ and other nitrogen oxides, the SCR reaction system with various reductants is widely used. This study is based on the results of experimental and theoretical examinations on the catalytic decomposition of sole nitrous oxide ($N_2O$) and selective catalytic reduction of $N_2O$ with $CH_4$ in the presence of oxygen using mixed metal oxide catalysts obtained from hydrolatcite-type precursors. When $CH_4$ is fed together with a reductant, it affects positively on the $N_2O$ decomposition activity. At an optimum ratio of $CH_4$ to $O_2$ mole ratio, the $N_2O$ conversion activity is enhanced on the SCR reaction with partial oxidation of methane.

• Journal of Climate Change Research
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• v.7 no.4
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• pp.427-432
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• 2016

Nitrous oxide is one of the main sources of greenhouse gases and its concentration has increased from 273 ppb in 1,750 to 315 ppb in 2005. Specially, nitrogen fertilizer used in agricultural soils is considered as an important source of atmospheric $N_2O$ emission. This study was conducted to estimate the difference of nitrous oxide emission as chamber position on furrow and ridge and crop existence in gas sampling chamber on upland. Four treatments used in this experiment were (1) no-fertilizer without crop in chamber on ridge, (2) fertilizer application without crop in chamber on ridge, (3) fertilizer application with crop in chamber on ridge, (4) fertilizer application without crop in chamber on ridge and furrow. Nitrous oxide emission at fertilizer application with crop in chamber on ridge were the highest while were the lowest at no-fertilizer without crop in chamber on ridge. There was no significant difference of nitrous oxide emission by chamber position, but total emission by crop existence in chamber was significant difference. Therefore, in order to estimate greenhouse gases emission using chamber method in upland, it should be considered in correlation with crop existence in chamber and characteristic changes like as the soil moisture, microbial flora by crop growth stage.

• Journal of the Korean Chemical Society
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• v.11 no.3
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• pp.105-110
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• 1967

The transient state theory of significant liquid structure is applied to nitrous oxide and nitrogen tetroxide. The partition functions for the two liquids are derived according to the transient state theory. The various thermodynamic properties; such as, molar volumes, vapor pressures, entropies of vaporization, and critical point properties agree well with the experimental values.