• 자원ㆍ환경경제연구
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• 제19권2호
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• pp.243-282
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• 2010

본 연구는 1991년~2007년간 우리나라 전력산업의 탄소배출에 미치는 요인들과 영향의 정도를 전력 수요측면과 공급측면으로 나누어 요인분해분석을 수행하였다. 전력수요측면에서는 전력사용의 효율성 향상이 배출 감소에 주된 영향을 미치는 반면, 전력을 소비하는 산업의 구조 변화는 오히려 배출을 증가시키는데 기여했음을 확인하였다. 공급측면에서는 탄소배출에 미치는 주요 요인으로 연료혼합, 화력발전효율, 발전구조의 변화 등이 있었으며 분석 결과 전력수요의 증가와 화력발전의 구조 변화가 탄소배출을 증가시키는 주요한 요인으로 작용한 반면 연료효율성은 향상되어 배출을 감소시키는 역할을 한 것으로 나타났다. 이로써 전력산업의 온실가스 감축을 위해 수요차원에서는 전력사용의 효율성을 향상시키고 공급차원에서는 화력발전을 대체하면서 발전 및 배출 효율성을 향상시킬 수 있는 정책이 마련되어야 한다는 것을 알 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.2140-2142
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• 2005

This paper presents the experimental results on the preliminary breakdown characteristics under a highly non-uniform electric field in $SF_6/CO_2$ gas mixtures. The impulse preliminary breakdown developments are investigated by the measurements of corona current and light emission images. As a result, the preliminary breakdown development mechanisms for both positive and negative polarities are same. The first streamer corona is initiated at the tip of needle electrode, and the leaders develop with a stepwise propagation and bridge the test gap. The pause time of leader pulses in the positive polarity is significantly shorter than that in the negative polarity. Also, the time interval between the first streamer corona onset and breakdown in the negative polarity was much longer than that in the positive polarity The discharge channel paths in the positive polarity were zigzag. On the other hands, the leader channel in the negative polarity was thicker than that in the positive polarity.

• 정보처리학회논문지D
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• 제18D권5호
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• pp.371-384
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• 2011

본 논문은 운송비용과 탄소배출비용을 고려한 최적 운송수단 선정에 대한 물류의사결정 시스템을 설계하고자 한다. 기존 연구는 운송비용과 운송모드별 용량을 고려하여 최적의 운송수단을 선정하였으나, 온실가스 배출규제에 대응하기 위해 운송비용과 용량 뿐만 아니라 탄소배출비용을 통합적으로 고려하여 물류체계를 설계할 필요성이 높아지고 있다. 따라서 본 논문에서는 탄소배출을 고려한 우리나라의 복합운송에 대한 운송수단 선택과 비용과 CO2배출의 Trade-off관계에 대한 접점을 찾아 분석하고 향후 나아갈 방안에 대해 제시하고자 한다. 탄소배출비용을 고려한 최적 운송수단 의사결정 문제는 혼합정수계획 모형으로 모델링되었으며, 운송비용과 탄소배출비용 사이의 관계를 분석하기 위하여 서울-부산 간 컨테이너 운송에 있어서의 다양한 시나리오를 도출하였다. 각각의 시나리오는 개발된 의사결정 시스템을 통하여 분석되었으며, 분석결과 단위 이동 거리당 탄소배출량이 낮은 것으로 알려져 있는 해상운송과 같은 대량운송 수단이 경우에 따라 더 많은 탄소를 배출하는 것으로 나타났다. 대량운송 수단의 경우 항만이나 철도역까지의 트럭운송에서의 우회가 증가된 탄소 배출의 주요 원인이었다. 제안된 물류의사결정 시스템은 녹색물류 및 그린SCM에서의 탄소배출비용과 물류비용사이의 관계를 이해하는데 역할을 할 것으로 기대된다.

• 환경영향평가
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• 제19권1호
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• pp.1-13
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• 2010

Ammonia ($NH_3$) is an important pollutant that plays a key role in several air pollution problems. It can create odors and have negative impacts on animal and human health. The largest source contributing to Ammonia emission is the agricultural production, in particular animal operation, in Korea. The present study evaluated flux profiles of Ammonia emitted from the cattle housing using a dynamic flux chamber. We have developed the emission factor of Ammonia from the cow housing. Analysis of Ammonia flux variation was made with respect to manure surface temperature, pH, and ammonium concentration. Ammonia has been measured from calf and cattle housing between October and December in 2007. In the fall, average Ammonia flux from calf and cattle housing was estimated 1.342(${\pm}0.728$) and 1.323(${\pm}0.655$)mg/$m^2$/min, respectively. In the winter, average Ammonia flux was estimated 0.889(${\pm}0.362$)mg/$m^2$/min from the calf housing and 0.925(${\pm}0.511$)mg/$m^2$/min from the cattle housing. The correlation coefficient between Ammonia flux and ammonium concentration showed stronger relationship than the relationship between manure pH and temperature. In the fall, Ammonia emission factor from calf and cattle housing was estimated 4.46(${\pm}2.39$) and 6.03(${\pm}3.27$)kg-$NH_3$/animal/yr, respectively. In the winter, average Ammonia flux was estimated 2.88(${\pm}1.53$) from the calf housing and 4.24({$\pm}1.63$)kg-$NH_3$/animal/yr from the cattle housing.

• 한국산업보건학회지
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• 제26권1호
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• pp.30-37
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• 2016

Objectives: This study was performed to measure and evaluate the concentration, size distribution and fugitive emission of particulate matter from process operations at foundries. Methods: Particle matter was collected from three foundries, and samples were also collected from a background site for calculating the fugitive emission concentration of the foundries. For the collection of the samples, a Nanosampler cascade impactor was used. Results: The concentration of TSP in the samples collected from the three foundries was $0.675{\sim}1.222mg/m^3$, $PM_{10}$ was $0.525{\sim}1.018mg/m^3$ and $PM_{2.5}$ was $0.192{\sim}0.615mg/m^3$. The mass size distribution was bimodal or monomodal with maximum peak at two stage(size $2.5{\sim}10{\mu}m$). The mass median aerodynamic diameter(MMAD) was $1.80{\sim}3.98{\mu}m$. The fugitive emission concentration of TSP varies in the range of 0.65 to $1.21mg/m^3$, which exceeds the emission standard of fugitive dust($0.5mg/m^3$). Conclusions: Particle concentration and size is an important industrial hygiene factor to protect foundry workers. Furthermore, the presence of high emission of particulate pollutants has a significant negative impact on the ambient air of the study area. Therefore, it is important to improve both the process and prevention facility in oder to reduce particulate pollutants in foundries.

• Bulletin of the Korean Chemical Society
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• 제32권6호
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• pp.1859-1864
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• 2011

Two lanthanide complexes, $[Ln(NO_3)_2(H_2O)_3(L)_2](NO_3)(H_2O)$ {Ln = Eu (1), Tb (2); L = 2-(4-pyridylium)-ethanesulfonate, $(4-pyH)^+-CH_2CH_2-SO_3^-)$}, were prepared from lanthanide nitrate and 4-pyridineethanesulfonic acid in $H_2O$ under microwave-heating conditions. Complexes 1 and 2 are isostructural, and the lanthanide metal in both complexes is coordinated to nine oxygen atoms. The pyridyl nitrogen in the ligand is protonated to give a zwitter ion that possesses an $NH^+$ (pyridyl) positive end and an $SO_3^-$ negative end. All O-H and N-H hydrogen atoms participate in hydrogen bonds to generate a two-dimensional (complex 1) or a three-dimensional network (complex 2). Complex 1 exhibits an intense red emission, whereas complex 2 exhibits an intense green emission in the solid state at room temperature.

• Environmental Engineering Research
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• 제22권3호
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• pp.266-276
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• 2017

A life cycle impact assessment was applied in an industrial waste incineration plant to evaluate the direct and indirect environmental impacts based on toxicity and non-toxicity categories. The detailed life cycle inventory of material and energy inputs and emission outputs was compiled based on the realistic data collected from a local industrial waste incineration plant, and the Korean life cycle inventory and ecoinvent database. The functional unit was the treatment of 1 tonne of industrial waste by incineration and the system boundary included the incineration plant and landfilling of ash. The result on the variation of the impact by the unit processes showed that the direct impact was decreased by 79.3, 71.6, and 90.1% for the processes in a semi dry reactor, bag filter, and wet scrubber, respectively. Considering the final impact produced from stack, the toxicity categories comprised 91.7% of the total impact. Among the toxicity impact categories, the impact in the eco-toxicity category was most significant. A separate estimation of the impact due to direct and indirect emissions showed that the direct impact was 97.7% of the total impact. The steam recovered from the waste heat of the incineration plant resulted in a negative environmental burden.

• 한국전기전자재료학회논문지
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• 제24권6호
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• pp.504-509
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• 2011

The conducting current of non-uniform plasma immersed electrode consists of ion current and secondary electron emission current caused by the impinging ion current. The ion current is determined by the ion dose passing through the sheath in front of electrode and the ion distribution in front of the electrode plays an important role in the secondary electron emission. The investigation of the distributed plasma and secondary electron effect on electrode ion current was carried out as the stainless steel electrode plugged with quartz tube was immersed in the inductively coupled Ar plasma using the antenna powered by 1 kw and the density profile was measured. After that, the negative voltage was applied by 1 kV~6 kV to measure the conduction current for the analysis of ion current.

• Advances in environmental research
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• 제9권2호
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• pp.123-133
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• 2020

A time series dataset was conducted to ascertain the effect of water table on the variability in and emission of CH₄ and CO₂ concentrations at a closed landfill site. An in-situ data of methane/carbon dioxide concentrations and environmental parameters were collected by means of an in-borehole gas monitor, the Gasclam (Ion Science, UK). Linear regression analysis was used to determine the strength of the correlation between ground-gas concentration and water table. The result shows CH₄ and CO₂ concentrations to be variable with strong negative correlations of approximately 0.5 each with water table over the entire monitoring period. The R² was slightly improved by considering their concentration over single periods of increasing and decreasing water table, single periods of increasing water table, and single periods of decreasing water table; their correlations increased significantly at 95% confidence level. The result revealed that fluctuations in groundwater level is the key driving force on the emission of and variability in groundgas concentration and neither barometric pressure nor temperature. This finding further validates the earlier finding that atmospheric pressure - the acclaimed major control on the variability/migration of CH₄ and CO₂ concentrations on contaminated sites, is not always so.

• 한국전기전자재료학회논문지
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• 제18권11호
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• pp.1056-1060
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• 2005

We investigated the fabrication and characteristics of the nitride-based spin-polarized LEDs with room-temperature ferromagnetic (Ga,Mn)N layer as a spin injection source. The (Ga,Mn)N thin films having room-temperature ferromagnetic ordering were found to exhibit the negative MR and anomalous Hall resistance up to room temperature, revealing the existence of spin-polarized electrons in (Ga,Mn)N films at room temperature. The electrical characteristics in the spin LEDs did not degraded in spite of the insertion of the (Ga,Mn)N layer into the LED structure. In EL spectra of the spin LEDs, it is confirmed that the devices produce intense EL emission at 7 K as well as room temperature. These results are expected to open up new opportunities to realize room-temperature operating semiconductor spintronic devices.