• 한국자동차공학회논문집
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• 제7권8호
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• pp.34-42
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• 1999

In late 1997, the portion of registered light-duty diesel vehicle was 25.3% and its emission rate was 17.1% in Korea. Especially, diesel particulate matters(DPM) and NOx are hazardous air pollutants to human health and environment in urban area. The reduction technologies of exhaust emissions from diesel engines are improvement of engine combustion, fuel quality and development of diesel exhaust after treatment , In this study , a light-duty diesel oxidation catalyst(DOC) that is one of the diesel exhaust after treatment was made for performance evaluation and the emission characteristics were tested on CVS-75 mode. And the analysis of the particle size distribution with scanning mobility particle 100, 67.6% and 66.7, 10.0% for Pt and Pt-V catalyst .And for Pt catalyst, the PM increased 7.8% because of increasing sulfate but Pt-V catalyst reduced the PM to 23.0% . Test results of particle size distribution showed that peak values of number and mass densities are respectively 100∼200nm their distribution trend independent of vehicle speed.

• 한국수소및신에너지학회논문집
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• 제29권5호
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• pp.512-522
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• 2018

This study was conducted to investigate on the combustion characteristic with the effects of mat thickness and fuel kinds in a metal-fiber burner. The mode transition point is confirmed by the K value, which was defined as the rate of flow velocity and laminar burning velocity. The ($T^4_{sur}-T^4_{\infty}$) is highest at methane flame with 3 T thickness. Through the measurement of the unburned mixture temperature, the possibility of submerged flame in surface combustion burner was confirmed. The rapid emission of CO occurs nearby limit blow out (LBO) because of the increase of flow velocity. In case of NOx, the trend is similar with surface temperature. However, it also considered that the NOx emission is affected by residence time with flame position.

• 한국태양에너지학회 논문집
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• 제32권1호
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• pp.32-39
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• 2012

New and renewable energy systems(solar thermal system, photovoltaic system, geothermal system, wind power system) are environmentally friendly technologies and these in South Korea are very important measures to reduce greenhouse-gas(GHG) and to push ahead with Green Growth. The purpose of this paper is to analyze GHG mitigation potential by distribution of solar thermal system in housing sector with bottom-up model called 'Long-range Energy Alternative Planning system'. Business as usual(BAU) was based on energy consumption characteristic with the trend of social-economic prospects and the volume of housing. The total amount of GHG emission of BAU was expected to continuous increase from 66.0 million-ton $CO_{2e}$ in 2007 to 73.1 million-ton $CO_{2e}$ in 2030 because of the increase of energy consumption in housing. The alternative scenario, distribution of solar thermal system in housing sector had GHG mitigation potential 1.54 million-ton $CO_{2e}$ in 2030. The results of this study showed that new and renewable energy systems made a contribution of reducing the use of fossil fuel and the emission of greenhouse-gas in building.

• Nuclear Engineering and Technology
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• 제55권12호
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• pp.4591-4596
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• 2023

Single-photon emission computed tomography SPECT image reconstruction methods have a significant influence on image quality, with filtered back projection (FBP) and ordered subset expectation maximization (OSEM) being the most commonly used methods. In this study, we proposed newly-designed adaptive non-blind deconvolution with a structural similarity (SSIM) index that can take advantage of the FBP and OSEM image reconstruction methods. After acquiring brain SPECT images, the proposed image was obtained using an algorithm that applied the SSIM metric, defined by predicting the distribution and amount of blurring. As a result of the contrast to noise ratio (CNR) and coefficient of variation evaluation (COV), the resulting image of the proposed algorithm showed a similar trend in spatial resolution to that of FBP, while obtaining values similar to those of OSEM. In addition, we confirmed that the CNR and COV values of the proposed algorithm improved by approximately 1.69 and 1.59 times, respectively, compared with those of the algorithm involving an inappropriate deblurring process. To summarize, we proposed a new type of algorithm that combines the advantages of SPECT image reconstruction techniques and is expected to be applicable in various fields.

• 농업과학연구
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• 제44권4호
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• pp.463-476
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• 2017

Climate change is considered as the greatest threat to our future and descendants. The Korean government has set a target for 2030 to reduce emission of greenhouse gases (GHGs) by 37% from the business-as-usual levels which are projected to reach 851 million metric tons of $CO_2eq$ (Carbon dioxide equivalent). In Korea, GHGs emission from agriculture account for almost 3.1% of the total of anthropogenic GHGs. The GHGs emitted from agricultural land are largely classified into three types: carbon dioxide ($CO_2$), methane ($CH_4$), and nitrous oxide ($N_2O$). In Korea, rice paddies are one of the largest agricultural $CH_4$ sources. In order to analyze domestic research trends related to $CH_4$ emission from rice paddies, 93 academic publications including peer reviewed journals, books, working papers, reports, etc., published from 1995 to September 2017, were critically reviewed. The results were classified according to the research purposes. $CH_4$ characteristics and assessment were found to account for approximately 65.9% of the research trends, development of $CH_4$ emission factors for 9.5%, $CH_4$ emission reduction technology for 14.8%, and $CH_4$ emission modeling for 6.3%, etc. A number of research related to $CH_4$ emission characteristics and assessment have been studied in recent years, whereas further study on $CH_4$ emission factors are required to determine an accurate country-specific GHG emission from rice paddies. Future research should be directed toward both studies for reducing the release of $CH_4$ from rice paddies to the atmosphere and the understanding of the major controlling factors affecting $CH_4$ emission.

• 한국대기환경학회지
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• 제32권6호
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• pp.603-612
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• 2016

The objective of this study was to estimate the emission characteristics for PM, $PM_{10}$, and $PM_{2.5}$ in the various stationary sources. The particulate matters collected in the various stationary sources such as power plants (Coal and B-C oil), incinerators(municipal and industrial waste), and glass furnaces. The PM and $PM_{10}$, PM and $PM_{2.5}$, $PM_{10}$ and $PM_{2.5}$ samples were collected using the cyclone type $PM_{10}$, $PM_{2.5}$ samplers and 30 species(19 inorganic species, 9 ionic species, OC and EC) were analyzed by ICP, IC, and TOR/IMPROVE methods. The mass concentrations of PM, $PM_{10}$, $PM_{2.5}$ from nine stationary sources ranged $0.63{\sim}9.58mg/Sm^3$, $0.26{\sim}7.47mg/Sm^3$ and $0.13{\sim}6.34mg/Sm^3$, respectively. The level of $PM_{10}$, $PM_{2.5}$ portion in PM calculated 0.63~0.99, 0.38~0.94, respectively. In the case of emission trend for species, power plant showed high concentrations for Al, Mg, Na, Si, V and $SO_4{^{2-}}$, respectively. Also, Ca, Fe, K, Si, $Cl^-$, and $K^+$ showed high in incinerator. In the case of glass furnace, Na, Pb, K, Si, $Na^+$ and $SO_4{^{2-}}$ represented high concentrations. Power plant showed higher EC/OC concentrations than other sampling sites. These results suggest the possible role for complement establishment process of emission inventory and emission management for PM.

• 한국대기환경학회지
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• 제20권2호
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• pp.175-183
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• 2004

In order to investigate the composition ratio and the emission rate of monoterpenes emitted from coniferous trees during summer, the enclosure chamber experiments were carried out for two tree species (Pinus densiflora and Pinus rigida). The major monoterpenes from the pine trees were $\alpha$-pinene, $\beta$-pinene, myrcene and $\beta$-phellandrene. There was no difference of the composition ratio between two sites for P. densiflora, but the difference was observed for P. rigida. Clearly, the ratio of $\beta$-pinene (26.1 %) for P. rigida was higher than that of $\beta$-phellandrene (12%) at the Gumsung mountain site, but the ratio of $\beta$-phellandrene (22.2%) was higher than that of $\beta$-pinene (9.9%) at the Chiri mountain site. Particularly, the composition ratio of $\beta$-phellandrene was higher than that of $\beta$-pinene for P. densiflora, and the opposite trend was found for P. rigida at the Gumsung mountain site. The characteristics of the composition ratio between two species were similar at the Chiri mountain site. As a result of the emission rate measurements, it was observed that both sites did not show any significant $\beta$ value (slope between emission rate and temperature) and ERs (Standard Emission rate at 3$0^{\circ}C$) difference. However, the $\beta$ value and ERs at the Chiri mountain site were slightly greater than those of Gumsung mountain site for both pine species. P. densiflora (1.703 and 1.971 $\mu\textrm{g}$C/gdw/hr) showed the higher monoterpene ERs than those of P. rigida (0.572 and 0.698 $\mu\textrm{g}$C/gdw/hr) at both sites.

• 한국대기환경학회지
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• 제8권4호
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• pp.240-246
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• 1992

During the period from December, 1990 to November, 1991, dustfall samples were collected by deposit jar at 28 sites in Seoul area and the amount of deposits of seven dissolved components$(SO_4^{2-}, NO_3^-, NH_4^+, Na^+, Ca^{2+}, Mg^{2+})$ were measured. The total amount of deposit was in order of Spring > Fall > Winter > Summer, and the amount of soluble components were high in the northeast region (Sanggae and Jangwe) and southwest region (Sangdo, Kuro, Siheung and Oryu). Total amount of major soluble components highly depended on regional air flow rather than emission source characteristic, and showed the regional trend-Residential > Iidustrial > Commercial > Rural, and the seasonal trend-Winter > Fall > Spring > Summer.

• 한국전기전자재료학회논문지
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• 제27권4호
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• pp.250-256
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• 2014

The wind power generation is an eco-friendly clean energy that produces almost zero $CO_2$ emission, and has a good economic feasibility. As for the location, the installation of large turbines and construction of large-scale wind farm is easier on the offshore than on the land. In Korea, it is inevitable to generate offshore wind power through the offshore wind farm, and the radio interference of larger wind power generators and offshore wind power farm to broadcasting, communication and radars is becoming a core issue for constructing the offshore wind farm. In this study, the wind power generation status and rotor blade technology trend were presented, along with the technical trend of radar radio interference reduction relating to construction of the offshore wind farm.

• Korean Chemical Engineering Research
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• 제54권1호
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• pp.22-35
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• 2016

본 연구에서는 CALPUFF 모델링을 수행하여 구미국가산업단지 공단지역에 악취로 인한 주민의 민원이 빈번한 지역과 아세트알데히드 배출 주요 점오염원인 구미국가산업단지 공단지역 합성섬유제조업체 악취배출시설과의 상관관계를 정립하고자 하였다. 본 연구의 CALPUFF 모델링 결과로서 T사 배출설비 개선 후에 구미공단의 아세트알데히드 농도의 최대값이 T사 배출설비 개선 전보다 O ($10^{-5}g/m^3$)에서 O ($10^{-6}g/m^3$)으로 저감되고 겨울(1월)과 봄(4월)에 구미 1공단의 아세트알데히드 농도가 개선되어서 구미 3공단에서 자주 아세트알데히드 농도의 구미공단 내 최대값이 도출되었다. 또한 T사 배출설비 개선 후에 도출된 아세트알데히드 농도의 구미공단 내 최대값 예측범위는 T사 배출설비 개선 전의 구미공단 내 최대값 예측범위보다 개선되었다. 이와 같은 총괄 점오염원의 아세트알데히드 기여도 평가 예측을 위한 CALPUFF 모델링 최대값은 '구미대구지역 HAPs 조사연구'의 측정 최대값 결과와 비교하였을 때에 상호 비교할 수 있는 비슷한 값을 보였고 민원추세와도 잘 일치하였다. 따라서 본 연구에서 총괄 점오염원의 아세트알데히드 기여도 평가 예측에 대한 유효성을 보여주었다. 한편 총괄 점오염원에서의 아세트알데히드 배출에 의하여 확산된 아세트알데히드 농도에 대한 T사 점오염원의 상대적 기여도가 T사 배출설비 개선 후에 개선 전보다 대부분 배 이상 낮아짐이 예측되었다. 반면에 이에 대한 W사 점오염원의 상대적 기여도는 T사 배출설비 개선 후가 T사 배출설비 개선 전보다 배 이상 증가하였다. 이것은 T사 배출설비 개선에 의하여 상대적으로 W사 점오염원의 아세트알데히드 기여도가 커졌음을 의미하였다.