• 한국입자에어로졸학회지
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• 제7권3호
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• pp.99-108
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• 2011

To establish area specific control strategies for the reduction of the ozone concentration, the Ozone Isopleth Plotting Package for Research(OZIPR) model has been widely used. However, the model results tend to changed by various input parameters such as the background concentration, emission amount of NOx and volatile organic compounds (VOCs), and meteorological condition. Thus, sensitivity analysis should be required to ensure the reliability of the result. The OZIPR modeling results for five local government districts in the Seoul Metropolitan Area (SMA) in June 2000 were used for the sensitivity analysis. The sensitivity analysis result showed that the modeling result of the SMA being VOC-limited region be still valid for a wide range of input parameters' variation. The estimated ozone concentrations were positively related with the initial VOCs concentrations while were negatively related with the initial NOx concentrations. But, the degree of the variations at each local district was different suggesting area specific characteristics being also important. Among the five local governments, Suwon was chosen to identify other variance through the period from April to September in 2000. The monthly modeling results show different ozone values, but still showing the characteristics of VOCs-limited region. Limitations due to not considering long range transport and transfer from neighbor area, limitation of input data, error between observed data and estimated data are all discussed.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1477-1479
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• 2005

In this work, the ITO thin films were prepared by FTS (Facing Targets Sputtering) system under different sputtering conditions which were varying $O_2$ gas flow, input current at room temperature. As a function of sputtering conditions, electrical and optical properties of prepared ITO thin films were measured. The electrical, optical characteristics and surface roughness of prepared ITO thin films were measured. In the results, as increasing $O_2$ gas 0.1[sccm] to 0.7[sccm], resistivity of ITO thin film was increased with a decreasing carrier concentration, $O_2$ gas over 0.3[sccm] the carrier mobility have a similarly value. Transmittance of prepared ITO thin films were improved at increasing $O_2$ gas 0.1[sccm] to 0.7[sccm]. And transmittance of all of the prepared ITO thin films was over 80%. We could obtain resistivity $6.19{\times}10^{-4}[{\omega}{\cdot}cm]$, carrier mobility $22.9[cm^2/V{\cdot}sec]$, carrier concentration $4.41{\times}10^{20}[cm^{-3}]$ and transmittance over 80% of ITO thin film prepared at working pressure 1mTorr, input current 0.4A without any substrate heating.

• Structural Engineering and Mechanics
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• 제56권2호
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• pp.257-273
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• 2015

Numerical value of correlation between effective parameters in the strength of a structure is as important as its stochastic properties in determining the safety of the structure. In this article investigation is made about the variation of coefficient of correlation between effective parameters in corrosion initiation time of reinforcement and the time of concrete cover cracking in reinforced concrete (RC) structures. Presence of many parameters and also error in measurement of these parameters results in uncertainty in determination of corrosion initiation and the time to crack initiation. In this paper, assuming diffusion process as chloride ingress mechanism in RC structures and considering random properties of effective parameters in this model, correlation between input parameters and predicted time to corrosion is calculated using the Monte Carlo (MC) random sampling. Results show the linear correlation between corrosion initiation time and effective input parameters increases with increasing uncertainty in the input parameters. Diffusion coefficient, concrete cover, surface chloride concentration and threshold chloride concentration have the highest correlation coefficient respectively. Also the uncertainty in the concrete cover has the greatest impact on the coefficient of correlation of corrosion initiation time and the time of crack initiation due to the corrosion phenomenon.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 추계학술대회 논문집
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• pp.203-207
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• 2007

Recently, ozone is utilized in various fields and its needs are expanding. In this paper, plate type ozonizer have been fabricated to investigate discharge parameter(input power, flow rate of supplied gas, electrode form, etc.) effect to discharge. And the conditions of discharge parameter have been investigated for optimum ozone generation. Ozone concentration is continuously increased with increasing input power for same discharge space, and ozone yield is also increased until maximum point after that it is saturated. Ozone concentration is inversely proportional to flow rate of supplied gas but ozone generation and ozone yield characteristics are improved.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 춘계학술대회 논문집
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• pp.379-380
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• 2008

Recently, ozone is utilized in various fields and its needs are expanding. In this paper, glass and ceramic plate tyre ozonizer have been fabricated to investigate discharge parameter(input power, flow rate of supplied gas, electrode form, etc.) effect to discharge. And the conditions of discharge parameter have been investigated for optimum ozone generation. Ozone concentration is continuously increased with increasing input power for same discharge space, and ozone yield is also increased until maximum point after that it is saturated. Ozone concentration is inversely proportional to flow rate of supplied gas but ozone generation and ozone vield characteristics are improved.

• 설비공학논문집
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• 제16권3호
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• pp.287-292
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• 2004

An experimental investigation was carried out to study the performance of a bubble pump for the diffusion absorption refrigerating system. Ammonia was used as the refrigerant and the helium was charged in order to balance the pressure between the low and high pressure side. As experimental variables, the concentration of ammonia charged into system, heat input, and the pressure of helium were selected. Experimental results show that the generation rate of ammonia vapor and the circulation rate of diluted ammonia solution were increased as the heat input increases, but the ratio of the solution to vapor flow rate was decreased. The generation rate of refrigerant vapor and the circulation rate of diluted ammonia solution increased as the system pressure decreased. Finally under the condition of 25 bars, the concentration of rich ammonia solution was not affected by the generation rate of ammonia vapor and the circulation of diluted ammonia solution.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.11-12
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• 2005

2 차원 MEDICI 시뮬레이터를 이용하여 CMOS 회로의 전기적 특성을 조사하였다. CMOS 인버터 회로는 LDMOSFET를 이용하였는데, LDMOSFET에서 전류 및 스위칭 특성에 많은 영향을 주는 곳은 채널이라고 생각되는데, 채널에서의 불순물 농도 변화에 의한 CMOS 회로의 voltage transfer특성, low input voltage($V_{IL}$), high input voltage($V_{IH}$)등을 조사하였다. LDMOSFET에서 N 채널의 농도는 $V_{IL}$에, P 채널의 농도는 $V_{IH}$에 많은 영향을 주었다.

• 조명전기설비학회논문지
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• 제22권1호
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• pp.149-156
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• 2008

최근 오존은 그 활용성을 인정받아 다양한 분야에서 사용되고 있으며, 그 수요 또한 계속 증가하는 추세이다. 이에 다양한 종류의 오존발생기가 연구되고 있으며, 고농도 및 고수율을 얻는 것이 연구목표라 할 수 있다. 본 논문에서는 전극 형태에 따른 평판형 오존발생기를 제작하여 원료가스의 유량 및 방전전력의 변화에 의한 오존생성농도, 오존생성량 및 오존생성수율 특성을 연구하였다.

• 한국수소및신에너지학회논문집
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• 제34권1호
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• pp.38-46
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• 2023

Carbon neutrality policies have been strengthened to reduce emissions, and the importance of technology road maps has been emphasized. In the global industrial boiler market, carbon neutrality is implemented through fuel diversification of methane-hydrogen mixture gas. However, various problems such as flashback and flame unstability arise. There is a limit to implementing the actual system as it remains in the early stage. Therefore, it is necessary to secure the source technology of methane-hydrogen hybrid combustion system applicable to industrial fields. In this study, control program for methane-hydrogen fuel conversion was developed to expect various parameters. After determining the hydrogen mixing ratio and the input air flow, the fuel conversion control algorithm was constructed to get the parameters that achieve the target oxygen concentration in the exhaust gas. LabVIEW program was used to derive correlations among hydrogen mixing rate, oxygen concentration in exhaust gas, input amount of air and heating value.

• Journal of Advanced Marine Engineering and Technology
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• 제39권4호
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• pp.456-462
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• 2015

본 연구는 토네이도와 축류펌프의 원리를 적용하여 마중물 없이 슬러리를 송출할 수 있는 새로운 펌프기술 개발을 목적으로 한다. 개발한 로터형 슬러리 펌프는 전동모터, 구동축 및 커플링, 로터, 임펠러 그리고 흡입 및 송출관으로 구성된다. 청수를 이용한 성능실험에서는 로터의 설계조건에 따른 송출량, 소비 전력량 그리고 흡입관 부압특성에 대해 모터의 회전수를 변수로 검증하였으며, 시멘트를 이용하여 제조한 슬러리의 고형물 농도에 따른 송출량 특성에 대한 검증연구를 수행하였다. 로터의 직경과 높이가 커지면 송출량과 소비되는 전력량은 증가하지만 흡입관 부압은 감소하였으며, 송출량과 부압에 미치는 로터 두께의 영향은 거의 나타나지 않았다. 개발지표로 제시하였던 18 % 이상의 고형물 농도에서도 슬러리의 송출이 가능함을 확인하였다.