• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2000년도 춘계학술대회 논문집
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• pp.200-202
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• 2000

온실가스의 배출자료는 기후변화협약 참여협상 및 저감대책 수립에 없어서는 안될 중요한 기초자료이다. 그러나 국내에서는 현재 에너지와 농업 분야를 제외하고는 온실가스의 배출원 및 배출량 조사가 미미한 실정이다. 이번 연구에서는 기후변화와 관련된 온실효과에 커다란 기여를 하고 있는 메탄($CH_4$)의 매립지 표면으로부터의 국내 배출량을 조사하고자 한다. $CO_2$, $CH_4$, $N_{2}O$, $O_3$, CFC 등의 주요 온실가스들은 여러 경로를 통해서 대기로 배출되고 있으며, 온실가스의 배출기여도를 보면 도시쓰레기의 매립이 전체 배출량에 약 3%정도 기여하는 것으로 보고되었다. (중략)

• 한국환경농학회지
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• 제26권2호
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• pp.131-140
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• 2007

Phospho-gypsum a primary waste by-product in phosphate fertilizer manufacturing industry and a potential source of electron acceptors, such as mainly of sulfate and a trace amount of iron and manganese oxides, was selected as soil amendment for reducing methane $(CH_4)$ emissions during rice cultivation. The selected amendment was added into potted soils at the rate of 0, 2, 10, and 20 Mg $ha^{-1}$ before rice transplanting. $CH_4$ flux from the potted soil with rice plant was measured along with soil Eh and floodwater pH during the rice cultivation period. $CH_4$ emission rates measured by closed chamber method decreased with increasing levels of phospho-gypsum application, but rice yield markedly increased up to 10 Mg $ha^{-1}$ of the amendment. At this amendment level, total $CH_4$ emissions were reduced by 24% along with 15% rice grain yield increment over the control. The decrease in total $CH_4$ emission may be attributed due to shifting of electron flow from methanogenesis to sulfate reduction under anaerobic soil conditions.

• 한국환경농학회지
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• 제33권4호
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• pp.306-313
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• 2014

BACKGROUND: Forest soils contain microbes capable of consuming atmospheric methane ($CH_4$), an amount matching the annual increase in $CH_4$ concentration in the atmosphere. However, the effect of plant residue production by different forest structure on $CH_4$ oxidation is not studied in Korea. The objective of this study was to evaluate the effect of Korean alpine soils having different forestation structure on $CH_4$ uptake rates. METHODS AND RESULTS: the $CH_4$ flux was measured at three sites dominated with pine, chestnut and oak trees in southern Korea. The $CH_4$ uptake potentials were evaluated by a closed chamber method for a year. The $CH_4$ uptake rate was the highest in the pine tree soil ($1.05mg/m^2/day$) and then followed by oak ($0.930mg/m^2/day$) and chestnut trees ($0.497mg/m^2/day$). The $CH_4$ uptake rates were highly correlated to soil organic matter and moisture contents, and total microbial and methanotrophs activities. Different with the general concent, there was no any correlation between $CH_4$ oxidation rates, and soil temperature and labile carbon concentrations, irrespective with tree species. CONCLUSION: Conclusively, the methane oxidation rate was correlated in positive manner with organic matter, abundance of methanotrophs. Methane oxidation was different among tree species. This results could be used to estimate methane oxidation rate in forest of Korea after complementing information about statistical data and methane oxidation of other site.

• Bulletin of the Korean Chemical Society
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• 제8권3호
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• pp.174-179
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• 1987

The results of an ab initio (6-31G) molecular orbital calculations of the dipole moment derivatives and gas phase IR intensities in $CH_3F$ and $CF_4$ are reported. The results are compared with corresponding values obtained from a CNDO calculation. We have also analyzed the theoretical polar tensors into the charge, charge flux, and overlap contributions. The effective term charges of hydrogen atom appeared to be transferable among the fluoromethane molecules.

• 대한기계학회논문집B
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• 제32권4호
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• pp.255-265
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• 2008

This paper presents the optimization process of evaporator for a vapor compression cooling system for high heat flux CPU. The CPU thermal capacity was given by 300W. Evaporating temperature and mass flow rate were $18^{\circ}C$ and 0.00182kg/s respectively. R134a was used as a working fluid. Channel width(CW) and height(CH) were selected as design factors. And thermal resistance, surface temperature of CPU, degree of superheat, and pressure drop were taken as objective responses. Fractional factorial DOE was used in screening phase and RSM(Response Surface Method) was used in optimization phase. As a result, CW of 2.5mm, CH of 2.5mm, and CL of 484mm were taken as an optimum geometry. Surface temperature of CPU and thermal resistance were $33^{\circ}C\;and\;0.0502^{\circ}C/W$ respectively. Thermal resistance of evaporator designed in this study was significantly lower than that of other cooling systems such as water cooling system and thermosyphon system. It was found that the evaporator considered in this work can be a excellent candidate for a high heat flux CPU cooling system.

• 한국환경농학회지
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• 제26권2호
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• pp.141-148
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• 2007

Fly ash, a by-product of the coal-burning industry, and a potential source of ferro-alumino-silicate minerals, which contains high amount of ferric oxide and manganese oxide (electron acceptors), was selected as soil amendment for reducing methane $(CH_4)$ emission during rice cultivation. The fly ash was applied into potted soils at the rate of 0, 2, 10, and 20 Mg $ha^{-1}$ before rice transplanting. $CH_4$ flux from the potted soil with rice plants was measured along with soil Eh and floodwater pH during the cropping season. $CH_4$ emission rates measured by closed chamber method decreased gradually with the increasing levels of fly ash applied but rice yield significantly increased up to 10 Mg $ha^{-1}$ application level of the amendment. At this amendment level, total seasonal $CH_4$ emission was decreased by 20% along with 17% rice grain yield increment over the control. The decrease in total $CH_4$ emission may be attributed due to suppression of $CH_4$ production by the high content of active and free iron, and manganese oxides, which acted as oxidizing agents as well as electron acceptors. In conclusion fly ash could be considered as a feasible soil amendment for reducing total seasonal $CH_4$ emissions as well as maintaining higher grain yield potential under optimum soil nutrients balance condition.

• 한국대기환경학회지
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• 제29권2호
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• pp.171-185
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• 2013

Wetland has been known as a major biogenic source of $CH_4$ in globe. In a global scale, the amounts of 55~150 Tg $CH_4$ are released into the atmosphere annually from wetlands; and it accounts for about 21% of total $CH_4$ annual global emission. From August 2010 to August 2011, measurements of major greenhouse gas ($CO_2$, $CH_4$, $N_2O$) emissions were conducted from a freshwater wetland at Kunsan ($35^{\circ}56^{\prime}38.94^{\prime\prime}N$, $126^{\circ}43^{\prime}16.62^{\prime\prime}E$), Korea by using floating closed static chamber method. Flux measurements for these gases from western coastal tidal flat at Seocheon ($36^{\circ}07^{\prime}13.85^{\prime\prime}N$, $126^{\circ}35^{\prime}43.18^{\prime\prime}E$), Korea were managed from July 2011 to February 2012 by using closed static chamber method. The average gas fluxes and ranges from freshwater wetland experiment were $0.155{\pm}0.29\;mg\;m^{-2}\;hr^{-1}$ (-0.054~0.942 $mg\;m^{-2}\;hr^{-1}$) for $CH_4$, $17.30{\pm}73.27\;mg\;m^{-2}\;hr^{-1}$ (-52.44~261.66 $mg\;m^{-2}\;hr^{-1}$) for $CO_2$, and $0.004{\pm}0.01\;mg\;m^{-2}\;hr^{-1}$ (-0.02~0.07 $mg\;m^{-2}\;hr^{-1}$) for $N_2O$, respectively. Monthly base flux measurement results revealed that $CH_4$ fluxes during summer months in high water temperature were significantly high, and at least order of one higher than those during other months. The average fluxes and ranges of these greenhouse gases from tidal flat during the experimental period were $0.002{\pm}0.08\;mg\;m^{-2}\;hr^{-1}$ (-0.16~0.22 $mg\;m^{-2}\;hr^{-1}$) for $CH_4$, $-31.18{\pm}75.33\;mg\;m^{-2}\;hr^{-1}$ (-298.87~101.93 $mg\;m^{-2}\;hr^{-1}$) for $CO_2$, and $0.001{\pm}0.01\;mg\;m^{-2}\;hr^{-1}$ (-0.017~0.03 $mg\;m^{-2}\;hr^{-1}$) for $N_2O$, respectively. Comparing the results of gas emissions from tidal flat to those from freshwater wetland, we found significantly lower emissions from tidal flat based on the experiment. Physicochemical parameters of water and soil at these experimental plots were also sampled and analyzed for understanding their correlation with these gas emissions.

• Bulletin of the Korean Chemical Society
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• 제7권5호
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• pp.380-384
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• 1986

The infrared intensities of $CH_{4}$ and $CD_{4}$ are analyzed. The experimental dipole moment derivatives thus obtained are compared with corresponding values from the molecular orbital calculations. The theoretical results are analyzed for the charge-charge flux-overlap(CCFO) electronic contributions to the dipole derivatives.

• 한국대기환경학회지
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• 제29권6호
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• pp.789-800
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• 2013

$N_2O$ and $CH_4$, Greenhouse gas emission, Forest soil, Closed chamber technique, Soil uptake $N_2O$ and $CH_4$ are important greenhouse gases (GHG) along with $CO_2$ influencing greatly on climate change. Their soil emission rates are highly affected by bio-geo-chemical processes in C and N through the land-atmosphere interface. The forest ecosystems are generally considered to be net emission for $N_2O$; however, net sinks for $CH_4$ by soil uptake. Soil $N_2O$ and $CH_4$ emissions were measured at Mt. Taewha in Gwangju, Kyeonggi, Korea. Closed chamber technique was used for surface gas emissions from forest soil during period from May to October 2012. Gas emission measurement was conducted mostly on daytime (from 09:00 to 18:00 LST) during field experiment period (total 25 days). The gas samples collected from chamber for $N_2O$ and $CH_4$ were analyzed by gas chromatography. Soil parameters were also measured at the sampling plot. GHG averages emissions during the experimental period were $3.11{\pm}16.26{\mu}g m^{-2}hr^{-1}$ for $N_2O$, $-1.36{\pm}11.3{\mu}gm^{-2}hr^{-1}$ for $CH_4$, respectively. The results indicated that forest soil acted as a source of $N_2O$, while it acted like a sink of $CH_4$ on average. On monthly base, means of $N_2O$ and $CH_4$ flux during May (spring) were $8.38{\pm}48.7{\mu}gm^{-2}hr^{-1}$, and $-3.21{\pm}31.39{\mu}gm^{-2}hr^{-1}$, respectively. During August (summer) both GHG emissions were found to be positive (averages of $2.45{\pm}20.11{\mu}gm^{-2}hr^{-1}$ for $N_2O$ and $1.36{\pm}9.09{\mu}gm^{-2}hr^{-1}$ for $CH_4$); which they were generally released from soil. During September (fall) $N_2O$ and $CH_4$ soil uptakes were observed and their means were $-1.35{\pm}12.78{\mu}gm^{-2}hr^{-1}$ and $-2.56{\pm}11.73{\mu}gm^{-2}hr^{-1}$, respectively. $N_2O$ emission was relatively higher in spring rather than other seasons. This could be due to dry soil condition during spring experimental period. It seems that soil moisture and temperature mostly influence gas production and consumption, and then emission rate in subsoil environment. Other soil parameters like soil pH and chemical composition were also discussed with respect to GHG emissions.

• 한국지구과학회지
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• 제34권3호
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• pp.209-223
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• 2013

이 연구의 목적은 한반도에서 $CH_4$ 농도의 수치모의 검증을 통하여 $CH_4$ 배출원의 기여 농도를 추정하는 것이고, 이 수치모의에 사용된 $CH_4$ 배출량을 상자모델로부터 추정된 $CH_4$ 배출량과 비교하는 것이다. 한반도에서 2010년 4월 1일부터 8월 22일까지 $CH_4$의 평균 농도를 추정하기 위해 WRF-CMAQ 모델이 사용되었다. 모델에서 $CH_4$ 배출량은 전지구 배출량인 EDGAR와 한국에서의 온실기체 배출량인 GHG-CAPSS로부터 인위적 배출 인벤토리와 전지구 자연적 인벤토리인 MEGAN이 적용되었다. 이들 $CH_4$ 배출량은 안면도 및 울릉도에서 측정된 $CH_4$ 농도와 모델링 농도 자료를 비교함으로써 검증되었다. 울릉도에서 국내 배출원으로부터 추정된 $CH_4$의 기여 농도는 약 20%로 나타났고, 이것은 한반도 내 농장(8%), 에너지 기여 및 산업공정(6%), 일반폐기물(5%), 생체 및 토지이용(1%) 등 $CH_4$ 배출원으로부터 기원하였다. 그리고 중국으로부터 수송된 $CH_4$의 기여 농도는 약 9%였고, 나머지 배경농도는 약 70%로 나타났다. 박스모델로 추정된 $CH_4$ 배출량은 WRF-CMAQ 모델에서 사용한 $CH_4$ 배출량과 유의미한 결과를 얻었다.