• 한국대기환경학회지
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• 제22권4호
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• pp.518-528
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• 2006

The air quality index (AQI) is an index for reporting daily or hourly air quality to the general public. The AQI focuses on health effects that can happen within a few hours or days after breathing polluted air. Many countries have their own AQI reporting systems, and the HAEI (hourly air environment index) method is now being used in Korea. In this study, in order to compare the AQI results from different methods, we applied three methods. i.e. US AQI, Canadian AQI, and Korean HAEI, to the same air quality data-base. The data-base was constructed from 10 monitoring sites in Gyeong-buk province for the last four years since 2000. Based on the results, a critical evaluation of the Korean HAEI method was made, and a number of suggestions and recommendations were presented to improve the AQI reporting system in Korea.

• 한국분무공학회지
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• 제19권3호
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• pp.142-148
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• 2014

In this study, characteristics of gaseous pollutants and particulate matter were investigated on the condition of DPF regeneration and normal DPF condition. THC, CO, $CO_2$, NOx, and $CH_4$ were analyzed by MEXA-7200H and CVS-7100 respectively. Particulate Matter (PM) was measured by difference in weight of Membrane filter. Particle Number (PN) was measured by CPC analyzer. And Sulfate, Nitrate, Organic were measured by Aerosol Mass Spectrometer (AMS). As a result, gaseous pollutants and particulate matter were detected in higher concentration during DPF regeneration than normal DPF condition. And the PN increased by 94%, the fuel consumption was reduced by 29% on DPF generation process. Sulfate, Nitrate and Organic were undetectable level during normal DPF condition. But the highest concentration of Sulfate, Nitrate and Organic were measured as $100{\mu}g/m^3$, $20{\mu}g/m^3$ and $15{\mu}g/m^3$ respectively on DPF regeneration condition. VOCs concentrations (Benzene, Toluene, Ethylbenzene, Xylene) were analyzed by using PTR-MS. Benzene and Toluene emission have little or no change depending on DPF regeneration. But the Ethylbenzene and Xylene have comparatively low emissions on DPF regeneration.

• 한국응용과학기술학회지
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• 제25권3호
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• pp.395-403
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• 2008

In this study, the characteristics of emulsified fuel were studied. The emulsified fuel which was composed of water and diesel was manufactured by using homogenizer and ultrasonic generator. The more the percentage of water contents increases, the more the density increases to the emulsified fuel. However, the viscosity increased in the 60% of water contents and decreased in the 70% of water contents because the O/W type was formed. The 3 minutes's ultrasonic waves during the irradiation time was appropriate of 16,000 rpm. And the energy density of ultrasonic waves was 87.5J/g. The emulsion stability has improved in the lower temperature, the lower percentage of water contents, and the most stable emulsion state was obtained from 20%(w/w) of water contents. Also, the emulsion stability was related to the HLB values of emulsifiers. Especially, the HLB values of emulsifier were appropriate from 4 to 7 values.

• International Journal of Automotive Technology
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• 제8권1호
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• pp.1-7
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• 2007

The effect of the di-tertiary butyl peroxide (DTBP) additive on the heat release rate and emissions of a homogeneous charge compression ignition (HCCI) engine fueled with high Research Octane Number (RON) fuels were investigated. The experiments were performed using 0%, 1%, 2%, 3%, and 4% (by volume) DTBP-RON90 blends. The RON90 Fuel was obtained by blending 90% iso-octane with 10% n-heptane. The experimental results show that the operation range was remarkably expanded to lower temperature and lower engine load with the DTBP additive in RON90 fuel. The first ignition phase of HCCI combustion was observed at 850 K and ended at 950 K while the hot ignition occurred at 1125 K for all fuels at different engine working conditions. The chemical reaction scale time decreases with the DTBP addition. As a result, the ignition timing advances, the combustion duration shortens, and heat release rates were increased at overall engine loads. Meanwhile, the unburned hydrocarbon (UHC) and CO emissions decrease sharply with the DTBP addition while the NOx emissions maintain at a lower level.

• 생약학회지
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• 제49권3호
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• pp.262-269
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• 2018

Sparassis crispa (Wulf.) is an edible/medicinal mushroom and has been reported to biological activities such as antitumor, anti-angiogenesis, antioxidant and wound healing. However, there have not been many researches on osteoarthritis of S. crispa. The aim of this study was to investigate the effects of S. crispa extract on rats with osteoarthritis induced by MIA. Osteoarthritis is a gradually developmental disease that early stage, causes joint stiffness and complains of joint pain. In addition, it gives rise to edema and hypo-function. The results of this study, S. crispa extract effectively inhibited ROS production, increased the production of antioxidant protein SOD and catalase in knee joint cartilage tissue. In addition, S. crispa extract inhibited the expression of pro-inflammatory cytokines and enzymes such as NOX4 and $P47^{phox}$, which are involved in the expression of COX-2, iNOS and the production of ROS. Also, S. crispa extract inhibited the destruction of synovial tissue, cartilage tissue and proteoglycans in articular cartilage in rats.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 추계학술대회 초록집
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• pp.91.1-91.1
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• 2011

고체산화물 연료전지(Solid Oxide Fuel Cell이하 SOFC)는 연료가 갖는 화학에너지를 연소과정 없이, 공기와 H2, CO, CH4와 같은 환원성 가스를 공급받아 $600{\sim}1000^{\circ}C$에서 전기화학적 반응을 통하여 직접 전기를 얻는 방식이다. SOFC는 $700^{\circ}C$ 이상의 고온에서 고체산화물이 연료와 공기가 반응하여 전기와 열을 동시에 생산하기 때문에 carnot cycle의 제한을 받지 않아 발전효율이 40% 이상으로 고효율이고, NOx 및 SOx를 배출하지 않아 무공해이며, moving parts가 없어 소음이 나지 않고, 건설과 증설이 지역이나 기후 조건에 제약 없이 용이하고, 다양한 용량이 가능하며, 고가의 백금 촉매를 사용하지 않으며, 수소, 석탄가스, 천연가스 등의 연료를 사용할 수 있는 장점이 있음, 또한 다향한 형태로 제작할 수 있으며 전해질이 고체에서 전해질 손실 및 보충에 문제가 없고 타 연료전지에 비해 개질기가 필요 없어 발전시스템이 간단하고 경량화가 가능하다. 전사법은 paste를 제작하여 전사용지에 Screen printing하여 건조 후 coating하는 방법으로 기존의 여러 coating 방법보다 제작이 용이하고 소재의 크기, 두께조절이 간편하며, 구성층의 표면조도나 굴곡에 대응이 용이한 방법이다. 본 실험에서는 paste 제조, 전사법을 이용하여 Anode, AFL, Electrolyte, CFL, Cathode전사지를 제작하고 이를 세라믹 평관형 지지체에 변수로 두께 조건별 Coating 한 후 $1400^{\circ}C$ 소결을 진행하여 SEM 분석으로 미세구조 관찰, 출력특성 및 Impedance을 확인하였다.

• International Journal of Automotive Technology
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• 제4권2호
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• pp.95-100
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• 2003

Automobile industry has been developed rapidly as a key manufacturing industry in Korea. Meanwhile, air pollution is getting worse noticeably than ever. In the diesel emission, PM (Particulate Matter) and NOx (Nitrogen Oxides) have been exhausted with a great amount and the corresponding emission regulations are getting stringent. In order to develop low emission engines, it is necessary to research on better qualified fuels. Sulfur contained in fuel is transformed to sulfur compound by DOC (Diesel Oxidation Catalyst) and then it causes to the increase of sulfate-laden PM on the surface of catalyst. In this research, ULSD (Ultra Low Sulfur Diesel) is used as a fuel and some experimental results are investigated. ULSD can reduce not only PM but also gas materials because cetane value, flash point, distillation 90%, pour point and viscosity are improved in the process of desulfurization. However, excessively reduced sulfur may cause to decease lubricity of fuel and engine performance in fuel injection system. Therefore, it requires only modest adjusted amount of sulfur can improve engine performance and DOC, as well as decrease of emission.

• 오토저널
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• 제10권5호
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• pp.61-68
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• 1988

This paper reports the basic performance of a naturally aspirated DI diesel engine which is used widely in industry and agriculture when vegetable oils are used as fuel substitutes. In this paper, the properties of vegetable oils as diesel fuel were investigated and the load-performance of diesel engine when vegetable oils were used, as tested compared against diesel fuel. The general objective of this investigation is to realize an efficient, clean, and low carbon deposit combustion of the vegetable oils in diesel engines, showing their feasibility as diesel fuel substitutes. The results of this experiment were as follows; (1) Compared with diesel fuel, the droplet size of vegetable oil is very large. (2) Compared with diesel fuel, rapeseed oil, palm oil, and their blend fuels offered lower smoke, lower NOx, ower engine noise, and high thermal efficiency in a D.I. diesel engine However, there were carbon deposit and piston ring sticking problems with long-term operation. (3) For ethanol-rapeseed oil blends, a 10-20% of ethanol content is recommended to enable lower BSHC and less smoke without a remarkable increase in engine noise compared with pure rapeseed oil. (4) A 10% oxygen content in the vegetable oils is contributed to reduced smoke emission.

• 한국자동차공학회논문집
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• 제19권3호
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• pp.23-28
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• 2011

To secure basic data for intake port design, effects of a port masking on the part load performance were investigated in a 4 valve SI engine. For this purpose, 9 kinds of masking, which have different shapes and masking ratio, are applied to the engine intake system. The characteristics of the performance were estimated through mixture response test at various engine load and speed. The results show that NOx emission, one of indexes for stratification, increases considerably in spite of retarded spark timing due to the stratification which is caused by unequal flow distribution between the two intake ports. The mechanism of stratification by masking is different from axial stratification and the fuel entering through masked port plays a very important role in this stratification process. In conclusion, the port masking method could be easily applied to engine intake system and be very effective for inducing the stratified charging without the change of port design.

• 한국수소및신에너지학회논문집
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• 제18권2호
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• pp.164-170
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• 2007

The Tancheon wastewater treatment plant(WWTP) in Seoul using anaerobic digestion to reduce the outlet sludge produces anaerobic digester gas which contains 65% $CH_4$ and 35% $CO_2$. The gas purification equipment was installed and operated to use Anaerobic Digester Gas(ADG) as a fuel for molten carbonate fuel cell(MCFC). The processes consist of the desulfurizer and the adsorption tower to remove $H_2S$ and siloxane in the gas. The gas purification equipment removed virtually over 95% of $H_2S$ and over 99% of siloxane. Results has demonstrated that the fuel cell can produce electrical output and hot water with negligible air emissions of CO, NOx and $SO_2$. The site provides the first opportunity in Korea for demonstrating Molten carbonate fuel cell(MCFC) which the digester gas was applied to the fuel gas.