• The Korean Journal of Ceramics
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• v.4 no.3
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• pp.222-226
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• 1998

$Cu_3N$ film deposited on silicon oxide substrate by r.f. reactive sputtering technique. Synthesis and properties of copper nitride film were investigated for its possible application to Cu metallization as adhesive interlayer between copper and $SiO_2. Cu_3N$ film was synthesized at the substrate temperature ranging from $100^{\circ}C$ to $200^{\circ}C$ and at nitrogen gas ratio above $X_{N2}=0.4. Cu_3N, CuN_x$, and FGM-structured $Cu/CuN_x$ films prepared in this work passed Scotch-tape test and showed improved adhesion property to silicon oxide substrate compared with Cu film. Electrical resistivity of copper nitride film had a dependency on its lattice constant and was ranged from 10-7 to 10-1 $\Omega$cm. Copper nitride film was, however, unstable when it was annealed at the temperature above $400^{\circ}C$.

• Journal of ILASS-Korea
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• v.25 no.3
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• pp.132-138
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• 2020

N₂O is hazardous atmosphere pollution matter which can damage the ozone layer and cause green house effect. There are many other nitrogen oxide emission control but N₂O has no its particular method. Preventing further environmental pollution and global warming, it is essential to control N₂O emission from industrial machines. In this study, the thermal decomposition experiment of N₂O gas mixture is conducted by using cylindrical reactor to figure out N₂O reduction and NO formation. And CHEMKIN calculation is conducted to figure out reaction rate and mechanism. Residence time of the N₂O gas in the reactor is set as experimental variable to imitate real SNCR system. As a result, most of the nitrogen components are converted into N2. Reaction rate of the N₂O gas decreases with N₂O emitted concentration. At 800℃ and 900℃, N₂O reduction variance and NO concentration are increased with residence time and temperature. However, at 1000℃, N₂O reduction variance and NO concentration are deceased in 40s due to forward reaction rate diminished and reverse reaction rate appeared.

• Advances in nano research
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• v.2 no.4
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• pp.179-186
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• 2014

Indium-nitrogen co-doped zinc oxide thin films (INZO) were prepared on glass substrates in the atmosphere by ultrasonic spray pyrolysis. The aqueous solution of zinc acetate, ammonium acetate and different indium sources: indium (III) chloride and indium (III) nitrate were used as the precursors. After film deposition, different anneal temperature treatment as 350, 450, $550^{\circ}C$ were applied. Electrical properties as concentration and mobility were characterized by Hall measurement. The surface morphology and crystalline quality were characterized by SEM and XRD. With the activation energy analysis for both films, the concentration variation of the films at different heat treatment temperature was realized. Donors correspond to zinc related states dominate the conduction mechanism for these INZO films after $550^{\circ}C$ high temperature heat treatment process.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.7
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• pp.640-648
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• 2002

This study is to develop electromagnetic-catalyst application plasma reactors for indoor air purification. Nitrogen Oxide(NOx) removal characteristics are measured in the electromagnetic catalyst application plasma reactors with various parameters and the effect of catalyst or/and magnetic field are investigated on the NOx removal. And AC or DC high voltage is applied for corona discharge, flow rates are 150~1500 $\ell/min$ and NO initial concentration is about 10 ppm. $Mn0_2$ and $TiO_2$ catalysts to increase NOx removal rate are used. In the results, NOx removal rate by AC power is about 10 % higher than that by DC power under the experimental condition of 700 $\ell/min$, 5 magnets, $MnO_2$ and $Ti)_2$ catalysts. When magnet is applied to the reactor, NOx removal rate increased. Also, the reactor with $MnO_2$ and $Ti)_2$ catalyst and magnet have the best removal rate.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.7
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• pp.1007-1014
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• 2003

This work deals with a controlled auto-ignition (CAI) single cylinder gasoline engine, focusing on the extension of operating conditions. The fuel is injected indirectly into electrically heated inlet air flow. In order to keep a homogeneous air-fuel mixing, the fuel injector is water-cooled by a specially designed coolant passage. Investigated are the engine performance and emission characteristics under the wide range of operating conditions such as 32 to 63 in the air-fuel ratio, 1000 to 1800 rpm in the engine speed, and 150 to 18$0^{\circ}C$ in the inlet air temperature. The compression ignition gasoline engine can be achieved that the ultra lean-burn with self-ignition of gasoline fuel by heating inlet air. For example. the allowable lean limit of air-fuel ratio is extended until 63 at engine speed of 1000 rpm and inlet air temperature of 17$0^{\circ}C$. It can be achieved that the emission concentrations of carbon monoxide, hydrocarbons and nitrogen oxide had been significantly reduced by CAI combustion compared with conventional spark ignition engine.

• Applied Chemistry for Engineering
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• v.32 no.4
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• pp.385-392
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• 2021

In this study, impact of Co proportion and calcination temperature of ceria on the Co/CeO₂ was analyzed by comparing nitrogen monoxide oxidation performance of various catalysts and their physico-chemical properties. The structural properties of each catalyst were studied by XRD and BET analysis, and the surface crystal states of cobalt were proposed according to the surface density. Oxidation states of elements were observed through Raman and XPS analysis, and the relationship between typical oxidation states and nitrogen monoxide oxidation performance was designed. Through H₂-TPR, oxygen-transferring capacity due to changes in the characteristics of catalysts were identified, and activation sites (Co³⁺) for oxidation were suggested.

• Journal of the Society of Naval Architects of Korea
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• v.61 no.2
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• pp.135-142
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• 2024

There is a lot of concern around the world about air pollution from ships. The majority of air pollution from ships comes from fuel combustion. The combustion process produces various air pollutants such as carbon monoxide (CO), carbon dioxide (CO₂), nitrogen oxides (NOx), sulfur oxides (SOx), and particulate matter (PM), each of which has adverse effects on people and is a major environmental problem. To prevent this, the International Maritime Organization (IMO) has strengthened the regulation of pollutant emissions through the Convention for the Prevention of Marine Pollution. This paper discusses the types of air pollutants emitted by ships, their current status, and the latest technologies to reduce emissions of NOx and SOx.

• Korean Journal of Soil Science and Fertilizer
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• v.18 no.1
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• pp.94-98
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• 1985

A laboratory experiment was conducted to find out the denitrification rate upon the different levels of nitrogen fertilizer in submerged sandy soil. The results obtained were summarized as follows: 1. The highest denitrification rate was observed at 25 days after incubation. The amount was reached at 1830 ug/100g soil for 20mg nitrogen was applied in 100g soil. 2. Increases of fertilizer nitrogen was enhanced the rate of ammonification and nitrification during the incubation time. 3. Deep correlation was observed between the denitrification capacities which was determined as nitrous oxide and Mitchaelis-Menten kinetic with relation to nitrate concentration. More higher denitrification rates were observed in Mitchaelis-Menten kinetic than dentrification rate with determined as nitrous oxide. 4. A Zero order (with relation to nitrate concentration) kinetic model for denitrification was presented in this experiment condition to illustrate the variability of nitrous oxide concentrations in the submerged soil atmosphere.

• Korean Journal of Soil Science and Fertilizer
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• v.47 no.1
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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.

• Korean Journal of Environmental Agriculture
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• v.39 no.4
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• pp.297-304
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• 2020

BACKGROUND: Emission of nitrous oxide (N2O) from the soil is expected to depend on the types of nitrogen fertilizer used. Biochar has recently been proposed as a potential mitigation of climate change by reducing the N2O emission. Although laboratory studies reported that biochar applications could reduce N2O emission, the number of field-based studies is still limited. Therefore, a field experiment was conducted to investigate the effect of biochar on N2O emission when different nitrogen fertilizers were applied in corn cultivated field. METHODS AND RESULTS: The field experiment consisted of six treatments: urea fertilizer without biochar (U), ammonium sulfate fertilizer without biochar (A), oil cake fertilizer without biochar (O), urea fertilizer with biochar (U+B), ammonium sulfate fertilizer with biochar (A+B), and oil cake fertilizer with biochar (O+B). Biochar was applied at a rate of 10 t/ha. Greenhouse gas fluxes were measured during growing seasons using static vented chambers. The cumulative N2O emissions were 0.99 kg/ha in the U, 1.23 kg/ha in the A, 3.25 kg/ha in the O, 1.19 kg/ha in the U+B, 0.86 kg/ha in the A+B, and 1.55 kg/ha in the O+B. CONCLUSION: It was found that N2O emission was related to application of both nitrogen fertilizer type and biochar. In particular, the N2O reduction effect was the highest in the corn field incorporated with biochar when oil cake was applied to the soil.