• Journal of Mechanical Science and Technology
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• 제18권12호
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• pp.2303-2309
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• 2004

Flue gas recirculation (FGR) is a method widely adopted to control NOx in combustion system. The recirculated flue gas decreases flame temperature and reaction rate, resulting in the decrease in thermal NO production. Recently, it has been demonstrated that the recirculated flue gas in fuel stream, that is, the fuel induced recirculation (FIR), could enhance a much improved reduction in NOx per unit mass of recirculated gas, as compared to the conventional FGR in air. In the present study, the effect of FGR/FIR methods on NOx reduction in turbulent swirl flames by using N$_2$ and CO$_2$ as diluent gases to simulate flue gases. Results show that CO$_2$ dilution is more effective in NO reduction because of large temperature drop due to the larger specific heat of CO$_2$ compared to N$_2$ and FIR is more effective to reduce NO emission than FGR when the same recirculation ratio of dilution gas is used.

• 한국레이저가공학회지
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• 제2권2호
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• pp.34-41
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• 1999

A RS840 $CO_2$laser and a powder auto-feeding apparatus have been used to deposit single tracks of Ni-base superalloy on low carbon steel. In this paper, the effects of laser cladding parameters on clad geometry, dilution and microhardness are studied. As a results, the w/h ratio of the clad layer increases with decreasing powder feed rate and increasing laser scan speed. Increase of powder density and decrease of specific energy have little effect on dilution. It was found that the clad layer of the highest hardness has a structure in which fine and leaf like phases are dispersed in ${\gamma}$Ni matrix.

• 한국방사선학회논문지
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• 제17권3호
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• pp.417-422
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• 2023

본 연구는 CT 검사 시 조영제로 기인한 화질 저하와 부작용을 감소시키기 위한 목적으로 식염수를 조영제에 일정 비율로 희석하였다. 이때 희석 정도에 따른 영상의 대조도 감소를 보상할 수 있는 DECT의 에너지 준위를 찾아 SNR, CNR, SSIM을 적용하여 비교 분석을 통해 영상 대조도 차 보상을 위한 DECT 적용의 유용성을 알아보았다. 그 결과 희석률 4(조영제) : 6(생리식염수), DECT의 에너지 준위 65 keV적용 시 조영제 원액을 사용했을 때와 가장 유사한 대조도 차가 형성되었고, 이때 SNR은 813.71±37.6, CNR은 921.87±17.1로 가장 높았으며, SSIM index가 1에 가장 유사한 0.851로 측정되었다. 본 연구결과는 향후 임상연구를 통해 검사부위별 적정 희석률과 에너지 레벨을 찾는 데 있어 기초정보를 제공하는 데 의미가 있으며 추가임상연구 결과를 임상에 적용한다면 조영제로 기인한 화질 저하와 부작용 문제를 줄여줄 수 있을 것으로 사료된다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 춘계학술발표강연 및 논문개요집
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• pp.98-98
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• 2003

비정질 실리콘 박막을 태양전지, 박막 트랜지스터, 이미지 센서, 컬러 디텍터 등에 적용하기 위한 많은 연구가 진행되고 있다. 이중 태양전지에 적용하기 위한 비정질 실리콘 박막은 p/i/n 다이오드 구조를 형성하게 되는데, 태양전지의 효율을 증가시키기 위해 결정질을 형성하거나 실리콘 화합물 박막을 적용한다. 본 연구에서는 비정질 태양전지의 흡수층(absorption layer)으로 사용되는 수소화된 비정질 박막의 결정화에 수소의 희석비가 미치는 영향을 파악하고자 하였다. PECVD 장비로 실란(SiH$_4$)과 수소(H$_2$) 가스를 이용하여 실리콘 박막을 증착하였고, 수소의 희석비(dilution ratio)를 변화시켜 비정질 실리콘 박막 내에 결정질 실리콘이 형성되는 정도를 관찰하였다. SEM과 Raman Spectroscopy를 이용해 박막의 두께 및 결정화도를 측정하였다. 실란에 대한 수소의 희석비가 증가할수록 증착률은 낮아지지만, 결정화도가 높아지는 것을 관찰할 수 있었다. 본 연구에서 형성한 결정질 실리콘 박막을 태양전지의 흡수층에 적용하면 효율 증가에 크게 기여할 것으로 판단된다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.455-456
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• 2000

Characteristics of $CO_2$ fixation by Chlorella sp. HA-1 were studied in a semi-continuous mode in a series operation. A high $CO_2$ fixation rate for a long time was obtained, when the method of semi-continuous mode was employed, in which the controlling parameter was the dilution ratio. A constant $CO_2$ fixation rate was maintained even when the dilution ratio was increased with the increment of 0.1 at the initial value of 0.5. The method of series operation was used to improve the efficiency of $CO_2$ fixation. The total amount of $CO_2$ fixation was proportion to the number of reactor in series operation.

• 한국전기전자재료학회논문지
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• 제15권10호
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• pp.851-857
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• 2002

CMP(chemical mechanical polishing) process has been attracted as an essential technology of multi~level interconnection. However, the COO(cost of ownership) is very high, because of high consumable cost. Especially, among the consumables, slurry dominates more than 40%. So, we focused how to reduce the consumption of raw slurry In this paper, we presented the pH changes of diluted slurry and pH control as a function of KOH contents. Also, the removal rates of slurry with different dilution ratio were investigated. Finally, the CMP characteristics were discussed as a function of silica (SiO$_2$) abrasive contents.

• Journal of Advanced Marine Engineering and Technology
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• 제36권6호
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• pp.774-779
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• 2012

MILD(Moderate and Intense Low Oxygen Dilution) 연소는 연소 가스의 재순환을 이용하여 고온 형성을 최대한 억제하고 질소산화물의 발생을 저감하는 동시에 연소로의 내부 온도 균일화를 통한 열 이용 효율을 향상시킬 수 있는 연소기술이다. 본 연구에서는 원추형 연소로에서 연료 유량은 고정하고 공기 유량으로 당량비(${\Phi}$)를 조절하고 배기가스를 측정하여 MILD 연소특성을 도출하였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 유기절연재료 전자세라믹 방전플라즈마 일렉트렛트 및 응용기술
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• pp.18-22
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• 2002

CMP(chemical mechanical polishing) process has attracted as an essential technology of multilevel interconnection. However, the COO(cost of ownership) is very high, because of high consumable cost. Especially, among the consumables, slurry dominates more than 40%. So, we focused that it has how to reduce the consumption of raw slurry. In this paper, we presented the pH changes of diluted slurry and pH control as a function of KOH contents. Also, the removal rates of slurry with different dilution ratio was investigated. Finally, CMP the characteristics as a function of silica($SiO_2$) abrasive contents were discussed.

• 대한전자공학회논문지
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• 제27권9호
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• pp.1402-1408
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• 1990

We studied the electrical, optical and structural properties of microcrystalline silicon thin films prepared by a new chemical vapour deposition technique, called filament assisted(FA)-CVD. The microcrystalline silicon is sucessfully deposited when the hydrogen dilution ratio exceeds 30. The Raman peak at 520 cm-1 and the X-ray diffraction peak at 27.7\ulcorner0.2\ulcornerbecome sharper with increasing hydrogen dilution ratio. We obtain high quality microcrystalline Si by FA-CVD with optical gap of \ulcorner2.2eV and hydrogen content of \ulcorner3 at %.

• 한국대기환경학회지
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• 제23권4호
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• pp.420-429
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• 2007

In this study, we attempted to evaluate the relationship between air dilution sensory test and instrumental detection method for individual odorous compound. For the purpose of our comparative study, we conducted the analysis of malodor on total of 46 samples collected from both industrial and food waste sectors using the two independent approaches. The results of instrumental analyses were explained after modification to several parameters such as: the sum of odor concentration (SOC), sum of odor quotient (SOQ) and sum of odor intensity (SOI). When we compared dilution ratio values (DRV) of threshold limit (TL) with the modified instrumental data sets, pearson coefficient of SOC, SOQ, and SOI were 0.556 (p=5.83E-05), 0.911 (p=9.64E-19) and 0.847 (p=8.93E-14), respectively. The results of this study thus suggest that the DRV of TL sensitively reflects odor strength measured intuitive.