• 펄프종이기술
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• 제44권4호
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• pp.32-42
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• 2012

Wood biomass including forest residues, waste wood, and construction residuals has been widely generated in Korea, but forest biomass from the National Forest Management Operation Project plays a big role in generating wood biomass. Unfortunately the promotion policy of woody energy organized by the Forest Service in Korea concentrates more on demand creation rather than on supply expansion. Therefore, in order to utilize insufficient wood resources effectively, it is greatly required to develop uses for maximizing their added value. In particular, more attention to the use of the second generation biomass has been paid in foreign countries because there is a threshold that the first generation biomass cannot produce enough biofuel without threatening food supplies and biodiversity. In Korea, wood pellets are regarded as the alternative clean fuels to oils and coals that emit green house gases into the atmosphere. However, using wood as pellet raw materials can not be an economic way because the value of wood disappears right after burning in the boiler in spite of its contribution to the decrease of carbon emission. Differently from wood pellets, kraft pulping process using woody biomass produces black liquor as a by-product which can be used to generate electricity, bioenergy and biochemicals through gasification. Thus, it can be more economical to make a torrefaction of lignocellulosic biomass such as low-quality wood and agricultural leftovers as raw materials of pellets.

• 공업화학
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• 제30권4호
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• pp.389-398
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• 2019

수소에너지는 화석연료의 사용으로 인해 나타나는 기후변화의 문제를 해결할 수 있는 방안일 뿐 아니라 산업용 전력 생산, 자동차용 연료 등을 위한 대체가능한 에너지로 인식되고 있다. 수소제조 방법 중 물의 전기분해를 이용한 방법이 가장 효율적이고 실용적인 방법으로 여겨지고 있으며, 수소를 물로부터 직접 제조하는 방법은 화석연료 이용 제조 방법과 비교하여 보았을 때 지구환경 오염물질인 메탄, 이산화탄소 등의 배출이 없다. 본 총설은 수소제조 방법 중 하나인 물 전기분해의 종류인 알칼리 수전해(alkaline water electrolysis, AWE), 고분자전해질막 수전해(polymer electrolyte membrane water electrolysis, PEMWE)에 대해서 분석하고 최근 연구 중인 탄화수소 전해질막의 동향 및 전해질막의 문제점인 크로스오버현상에 대해 설명하였다.

• 한국환경과학회지
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• 제28권2호
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• pp.169-182
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• 2019

Temporal and spatial variations in surface ozone concentrations in Busan were investigated by using observation data from urban air quality sites during 2001-2016. The annual ozone concentrations showed a significant increasing trend of $+0.40ppb\;yr^{-1}$ in this period, with a more rapid increase of $+0.81ppb\;yr-1$ since 2010. For the monthly analysis, the increase in ozone concentration was the greatest in August ($+0.68ppb\;yr-1$). These ozone trends were due mainly to rising temperature ($+0.05^{\circ}C\;yr^{-1}$) and weak decreasing precipitation ($-6.42mm\;yr^{-1}$). However, the extreme weather events (heat wave, localized heavy rain, etc.) lead to an increase in short-term variability of ozone since 2010. The relatively low ozone concentrations in the downtown area were caused by high NOx emissions from mobile sources. The increases in ozone concentrations were observed at most of the air quality monitoring sites due to the reductions in anthropogenic emissions of NOx during 2001-2015. However, in the southern coastal area, lower rates of increase in ozone concentrations were observed by $-0.10{\sim}0.25ppb\;yr^{-1}$ due to the significant NOx emitted by ships in the Busan port and Busan new port.

• 한국항행학회논문지
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• 제25권5호
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• pp.409-414
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• 2021

미세먼지에 대한 심각성이 사회적으로 대두됨에 따라 대중들은 미세먼지 예보에 대한 정보의 높은 신뢰성을 요구하고 있다. 이에 따라 다양한 신경망 알고리즘을 이용하여 미세먼지 예측을 위한 연구가 활발히 진행되고 있다. 본 논문에서는 미세먼지 예측을 위해 다양한 알고리즘으로 연구되고 있는 신경망 알고리즘들 중 대표적인 알고리즘들의 예측 성능 비교를 진행하였다. 신경망 알고리즘 중 DNN(deep neural network), RNN(recurrent neural network), LSTM(long short-term memory)을 이용하였으며, 하이퍼 파라미터 탐색을 이용하여 최적의 예측 모델을 설계하였다. 각 모델의 예측 성능 비교 분석 결과, 실제 값과 예측 값의 변화 추이는 전반적으로 좋은 성능을 보였다. RMSE와 정확도를 기준으로 한 분석에서는 DNN 예측 모델이 다른 예측 모델에 비해 예측 오차에 대한 안정성을 갖는 것을 확인하였다.

• 접착 및 계면
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• 제23권2호
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• pp.17-24
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• 2022

양자점은 수 나노미터 크기의 반도체 나노입자로 우수한 발광 특성 및 색순도, 간단한 밴드갭 조절의 장점 때문에 이를 발광원으로 사용한 양자점 디스플레이가 차세대 디스플레이로 주목받고 있다. 하지만 전하 주입 불균형 문제로 인해서 소자의 효율 및 안정성에 큰 문제가 발생하고 이를 해결하기 위한 많은 연구가 진행되었다. 본 논문에서는 전자 및 정공 수송층에 중간층을 삽입하여 양자점 디스플레이의 발광과 수명 특성을 향상시킨 연구와 정공 수송층의 구조 변화를 통해서 정공 수송 능력을 향상시킨 연구들에 대해서 소개하고자 한다.

• Advances in Energy Research
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• 제8권1호
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• pp.73-93
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• 2022

Focus on climate change and extreme weather conditions has received considerable attention in recent years. Civil engineers are now focusing on designing buildings that are more eco-friendly in the face of climate change. This paper describes the research conducted to assess the impact of future climate change on energy usage and carbon emissions in a typical supermarket at multiple locations across the UK. Locations that were included in the study were London, Manchester, and Southampton. These three cities were compared against their building performance based on their respective climatic conditions. Based on the UK Climatic Projections (UKCP09), a series of energy modelling simulations which were provided by the Chartered Institute of Building Service Engineers (CIBSE) were conducted on future weather years for this investigation. This investigation ascertains and quantifies the annual energy consumption, carbon emissions, cooling, and heating demand of the selected supermarkets at the three locations under various climatic projections and emission scenarios, which further validates annual temperature rise as a result of climatic variation. The data showed a trend of increasing variations across the UK as one moves southwards, with London and Southampton at the higher side of the spectrum followed by Manchester which has the least variability amongst these three cities. This is the first study which investigates impact of the climate change on the UK supermarkets across different regions by using the real case scenarios.

• 방사선산업학회지
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• 제17권4호
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• pp.427-436
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• 2023

As a result of evaluating the level of tritium emitted from the nuclear power plant in the environment and the human body, it was confirmed that tritium was detected in the environmental media and human urine samples to be investigated. It was found that the tritium was clearly detected. After the operation of the Tritium Removal Facility (TRF), which was operated for the purpose of removing tritium from the Wolsong nuclear power plant, the tritium emission showed a decreasing trend, and the tritium level in the environmental media also showed a tendency to decrease accordingly. However, for precise evaluation, it was necessary to select and investigate points by distance, season, and wind direction from the nuclear power plant, but it also showed characteristics that did not reflect this. As the cycle, etc., implemented the previous environmental monitoring program as it is, there was also a limitations in not being able to reflect the changing environment. Therefore, it is necessary to review and supplement the environmental monitoring investigation plan and results so far, and by applying the supplemented investigation plan to secure valid and reliable investigation results, it is judged that it will be an appropriate measure for environmental conservation and human protection in the vicinity of the nuclear power plant.

• 한국지리정보학회지
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• 제18권4호
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• pp.43-58
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• 2015

급격한 경제 성장과 인구 증가는 온실가스 배출량을 급증시키고 있으며 이는 기후변화를 가속화시키고 있다. IPCC(Intergovernmental Panel on Climate Change) 보고서는 온실가스가 2000년부터 2030년까지 최대 90%까지 증가할 것이라고 보고하고 있다. 이에 전 세계에서는 기후변화에 대한 피해를 줄이기 위해 기후변화 적응과 완화 대책 수립이 중요시되고 있으며, 우리나라에는 기후변화 대응 정책으로'저탄소 녹색성장(Low Carbon Green Growth)'을 시행하였다. 지자체에서는 친환경적이며 지속가능한 발전을 위한 도시계획을 조성하기 위해 다양한 연구를 수행해왔다. 특히, 기후변화에 가장 크게 영향을 줄 수 있는 토지이용변화에 대한 연구가 활발하게 수행되어지고 있는 실정이다. 본 연구에서는 제주도를 대상으로 경제적, 지리적 특성을 기반한 토지이용 균형 모델을 적용하여 주거 토지이용변화와 인구 밀도를 예측하였다. 먼저, 주거부분의 토지이용변화를 보기 위해, 3가지 유형의 시나리오를 구축하였다. 시나리오는 현재와 동일한 환경을 갖는 Dispersion 시나리오, 기후변화 적응 대책을 반영한 Adaptation 시나리오, 기후변화 적응과 완화 대책을 동시에 반영한 Combined 시나리오이다. 그 결과, 전반적으로 Dispersion 시나리오에서 Combined 시나리오로 갈수록 주거면적과 인구밀도가 줄어들었다. 이후 주거면적과 인구밀도 결과를 통해 시나리오별 주거용 에너지 소비량과 예상 인명 피해액을 산정하였다. 그 결과, 전반적으로 Dispersion 시나리오에서 Combined 시나리오로 갈수록 에너지 소비량과 예상 인명 피해액은 줄어들었다. 본 연구에서 제시한 토지이용균형모델을 적용하여 시나리오별 주거부분 토지이용과 인구 밀도 변화 파악은 향후 기후변화 안정성을 확보하고 완화할 수 있는 환경적 도시계획을 수립하는데 도움을 줄 수 있을 것으로 기대된다.

• 한국토양비료학회지
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• 제33권1호
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• pp.52-60
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• 2000

축분퇴비의 시용시 보충하는 비종에 따른 하우스 내부의 가스 발생양상과 미생물의 다양성을 구명하여 가스피해 정감 및 토양건전성 유지를 위한 기초자료를 얻고자 식양질 하우스토양에 축분퇴비의 시용량을 고추의 기준시비량과 퇴비에 함유된 인산함량을 기준하여 정식 2주전에 시용하고 부족한 질소성분을 요소와 완효성U/F복비로 보충처리하여 4월부터 8일 까지 재배하였다. 암모니아 및 아민류 가스는 정식초기에는 다소 낮은 농도로 배출되다가 정식 후 27일경에 peak를 보인 후 급격히 감소하여 33일경 이후에는 검출되지 않았으며, 평균농도는 요소구에 비하여 완효성U/F복비구가 암모니아 42%, 아민류 85%감소되었다. 이산화탄소는 요소구 1,200~3,200, 완효성U/F복비구 $900{\sim}2,650mg\;{\ell}^-$의 범위로 배출되었고, 평균농도는 요소구 2,260, 완효성U/F복비구 $1,590mg\;{\ell}^-$이었다. 세균, 방선균, B/F비, A/F비, 암모니아 및 아질산산화세균, 질산환원균 등의 밀도는 재배기간이 경과됨에 따라 완효성U/F복비구에서 더 높았으나 사상균 수는 요소구에서 많았고 탈질균은 비슷한 경향을 보였다. 조사한 6종 미생물 밀도의 백분율을 이용한 다양성지수는 0.10~0.35 범위로 재배기간이 경과함에 따라 감소하는 경향이었으며, 처리간에는 완효성U/F복비구가 요소구에 비하여 더 높았다.

• 한국습지학회지
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• 제9권1호
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• pp.79-89
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• 2007

This paper provides a comprehensive overview of the present status of several environmental problems caused by emerging toxic substances such as persistent organic pollutants (POPs), endocrine disrupting chemicals (EDCs), and arsenic in various environmental media in Vietnam. Monitoring data reported during the 1990s demonstrated elevated contamination of DDTs in most of these compartments in Vietnam. Studies in frame of the Asia-Pacific Mussel Watch Program revealed that fish, mussels and resident birds from Vietnam contained higher concentrations of DDTs as compared to other countries in region, suggesting the role of Vietnamese environment as a significant emission source of DDT in the Southeast Asian region. The estimated dietary intakes of PCBs and DDTs for Vietnamese were relatively high among Asian developing countries, suggesting potential risk for humans posed by thesechemicals. Widespread contamination of some endocrine active compounds such as alkylphenols and phthalates was observed at various sites along the coasts of northern and middle Vietnam. The presence of significant source of bisphenol-A along Red River estuary was revealed with the concentrations comparable to those reported for developed nations. A case study on seasonal variation of alkylphenols and phthalates in surface water of river delta and estuary of north and middle Vietnam indicated the differences in distribution of these compounds between dry and rainy seasons. Higher concentrations of alkylphenols and phthalates were found in dry season in estuary; while the contrasting pattern was observed in the river delta, showing elevated residues in rainy season. This result suggests the different behavior of alkylphenols and phthalates in river delta and coastal environment. From ecotoxicological perspectives, concentrations of bis-phenol A and di(2-ethylhexyl)phthalates [DEHP] in surface water from some locations in Vietnam exceeded the guideline values for Ecotoxicological Effects and the Environmental Risk Limit, respectively, suggesting potential for toxic implications on aquatic wildlife. Widespread and elevated arsenic contamination was discovered inour recent surveys in groundwater in a large area of suburban areas of Hanoi city, the capital of Vietnam. The most recent investigation in 4 villages showed about more than 50 % of groundwater samples contained As concentrations exceeding 50 g/L (the WHO and Vietnamese standard). In particular, in Son Dong villages, 58 % of samples analyzed contained As concentrations higher than 200 g/L. Good correlations were found in As concentrations in water and hair and urine of peoples in corresponding families, suggesting the chronic exposure to As by people living in As-contaminated ground water areas. In Son Dong village, As levels in hair (mean: 1.7 mg/kg dry wt) and urine (g/g creatinine) exceeding the reference values recommended by WHO, suggesting potential for human risk posed by long term accumulation of As in human body. Future studies should be focused on the time trends of POPs and EDCs in biota in Vietnam in order to predict future trend of contamination and to reveal new clues for understanding possible toxic impacts on aquatic organisms. The issues of arsenic contamination in groundwater and their chronic toxic implications on human health should be systematically investigated in the future.