• 한국연소학회지
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• 제7권2호
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• pp.15-23
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• 2002

We measured emission indices for $NO_x$, CO, temperature and radical characteristics for partially premixied flames formed by suction & blow fans air condition. At sufficiently high levels of partial premixing a double flame structure consisting of a rich premixed inner flame and outer diffusion flame was established similar to that previously observed in premixed flames. $NO_x$, Temperature. CO concentration were experimented with approximately constant air flow rate and decreasing equivalence ratios. The reduction in $NO_x$, and temperature at suction condition as compared with that for blow condition was approximately 20%, but on the contrary, CO emission was increased. In addition, We measured temperature distributions and found that temperature increased continuously with increasing partial premixing. We also estimated CH, $C_2$ radical intensity. CH and $C_2$ radicals provide evidence that, for the present measurement, CH and $C_2$ radicals intensity was associsated with their premixed component. And we observed stronger $C_2$, CH radicals intensity at suction conditions than blow conditions.

• 천문학회보
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• 제41권2호
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• pp.40.1-40.1
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• 2016

We present the far-ultraviolet fluorescent molecular hydrogen ($H_2$) emission map observed with FIMS/SPEAR for ~76% of the sky. The fluorescent $H_2$ emission is found to be saturated by strong dust extinction at the optically thick, Galactic plane region. However, the extinction-corrected intensity of fluorescent $H_2$ emission is found to have strong linear correlations with the well-known tracers of the cold interstellar medium, such as the E(B-V) color excess, neutral hydrogen column density N(HI), $H{\alpha}$ emission, and CO $J=1{\rightarrow}0$ emission. The all-sky molecular hydrogen column density map is also obtained using a photodissociation region model. We also derive the gas-to-dust ratio, hydrogen molecular fraction ($f_{H2}$), and $CO-to-H_2$ conversion factor ($X_{CO}$) of the diffuse interstellar medium. The gas-to-dust ratio is consistent with the standard value $5.8{\times}10^{21}atoms\;cm^{-2}mag^{-1}$, and the $X_{CO}$ tends to increase with E(B-V), but converges to the Galactic mean value $1.8{\times}10^{20}cm^{-2}K^{-1}km^{-1}s$ at optically thick regions with E(B-V)>2.0.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.143-148
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• 2001

We measured emission indices for $NO_x$, CO, temperature and radical characteristics for partially premixied flames formed by suction & blow fans air condition. At sufficiently high levels of partial premixing a double flame structure consisting of a rich premixed inner flame and outer diffusion flame was established similar to that previously observed in premixed flames. $NO_x$, Temperature, CO values were experimented with approximately constant air flow rate and decreasing equivalence ratios. The reduction in $NO_x$ and temperature at suction condition as compared with that for blow condition was approximately 20%, but on the contrary, CO emission was increased. In addition, We measured temperature distributions and found that temperature increased continuously with increasing partial premixing. We also estimated CH, $C_2$ radical intensity. CH and $C_2$ radicals provide evidence that, for the present measurement, CH and $C_2$ radicals intensity was associsated with their premixed component. And we observed stronger $C_2$, CH radicals intensity at suction conditions than blow conditions.

• 한국기후변화학회지
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• 제8권3호
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• pp.213-220
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• 2017

The purpose of this study is to analyze effects of Greenhouse Gas (GHG) emission reduction in district energy business mainly based on Combined Heat and Power (CHP) plants. Firstly this paper compares the actual carbon intensity of power production between conventional power plants and district energy plants. To allocate the GHG from CHP plants, two of different methods which were Alternative Generation Method and Power Bonus Method, have been investigated. The carbon intensity of power production in district energy plants ($0.43tonCO_2e/MWh$) was relatively lower than conventional gas-fired power plants ($0.52tonCO_2e/MWh$). Secondly we assessed the cost effectiveness of reduction by district energy sector compared to the other means using TIMES model method. We find that GHG marginal abatement cost of 'expand CHP' scenario (-$134/ton$CO_2$) is even below than renewable energy scenario such as photovoltaic power generation ($87/ton$CO_2$). Finally the GHG emission reduction potential was reviewed on the projected GHG emission emitted when the same amount of energy produced in combination of conventional power plants and individual boilers as substitution of district energy. It showed there were 10.1~41.8% of GHG emission reduction potential in district energy compared to the combination of conventional power plants and individual boilers.

• 천문학회지
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• 제35권2호
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• pp.97-103
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• 2002

We have mapped 1 $deg^2$ region toward a high latitude cloud MBM 40 in the J = 1 - 0 transition of $^{12}CO$ and $^{13}CO$, using the 3 mm SIS receiver on the 14 m telescope at Taeduk Radio Astronomy Observatory. We used a high resolution autocorrelator to resolve extremely narrow CO linewidths of the molecular gas. Though the linewidth of the molecular gas is very narrow (FWHP < 1 km $s^{-1}$ ), it is found that there is an evident velocity difference between the middle upper part and the lower part of the cloud. Their spectra for both of $^{12}CO$ and $^{13}CO$ show blue wings, and the position-velocity map shows clear velocity difference of 0.4 km $s^{-1}$ between two parts. The mean velocity of the cloud is 3.1 km $s^{-1}$. It is also found that the linewidths at the blueshifted region are broader than those of the rest of the cloud. We confirmed that the visual extinction is less than 3 magnitude, and the molecular gas is translucent. We discussed three mass estimates, and took a mass of 17 solar masses from CO integrated intensity using a conversion factor $2.3 {\times} 10^{20} cm^{-2} (K\;km s^{-1})^{-1}$. Spatial coincidence and close morphological similarity is found between the CO emission and dust far-infrared (FIR) emission. The ratio between the 100 f.Lm intensity and CO integrated intensity of MBM 40 is 0.7 (MJy/sr)/(K km $s^{-1}$), which is larger than those of dark clouds, but much smaller than those of GMCs. The low ratio found for MBM 40 probably results from the absence of internal heating sources, or significant nearby external heating sources.

• 청정기술
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• 제26권3호
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• pp.211-220
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• 2020

본 연구는 80 kW급 단일버너 연소로에서 석탄 연소시 초저 NOx 버너 설계인자를 평가하기 위한 실험적 연구이다. 버너 설계 인자인 선회강도, 총 과잉 공기비, 버너 영역 과잉공기비, 1차/2차 산화제 비율, OFA 비율을 변경하여 총 81개 조건을 대상으로 실험을 수행 하였다. 실험 결과, 선회류가 약하면 연소로 출구에서 CO가 증가하고 연소로 내부 온도가 감소하는 것으로 나타났다. 그러나, 선회류가 강하면 NOx가 증가하기 때문에 적절한 선회류 강도를 결정하는 것은 NOx를 줄이는 데 중요한 요소이다. 1차/2차 산화제의 비율 또한 중요한 요소이며, 생성 된 NOx의 양은 산화제의 비율에 따라 달라진다. 2차 산화제의 비율이 증가하면 연소 초기에 NOx 방출량이 증가하고, 측정 된 배출구 NOx가 증가하게 된다. 그러나, 2차 산화제 비율이 감소하면 화염이 길어지고 CO가 증가한다. 본 연구에 사용 된 연소 시스템은 적절한 조건이 만족 될 때 O₂ 6%를 기준으로 최소 NOx가 82 ppm 생성되는 것으로 확인 되었다. 본 실험에서 대상으로 한 버너는 연소용 공기를 석탄을 이송하는 1차공기 외에 2차공기로 하나의 산화제 유동만 사용하는 방식으로서 추후 3차 및 4차공기로 분할하여 화염형태 및 반응을 세밀하게 제어할 경우 추가적인 NOx 감소가 가능할 것으로 예상된다.

• 한국세라믹학회지
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• 제37권2호
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• pp.134-139
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• 2000

The main objective of the present investigation is to show the feasibility of combinatorial chemistry by applying this method to phosphor syntehses. In this respect barium hexaaluminate phosphor was prepared by the split-pool combinatorial method, which enabled much more rapid search of optimum compositions of target phosphors than conventional synthetic methods. Barium hexaaluminate phosphors doped with Eu2+ exhibit blue emission while those co-doped with Mn2+ and Eu2+ exhibit green emission. Basically, the phosphor doped with 1.3 mole of Ba and 0.06~0.15 mole of Eu2+ exhibit the maximum value of emission intensity at 435${\mu}{\textrm}{m}$. Under the UV and VUV extitations, the barium hexaaluminate phosphor co-doped with Mn2+ and Eu2+ shows strong green emission.

• 한국건축시공학회지
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• 제11권3호
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• pp.247-255
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• 2011

한국은행에서 2000년도에 발행된 산업연관표를 적용한 주요 건축자재의 에너지소비량과 $CO_2$ 배출에 대한 원단위 DB는 있지만 2005년, 2007년에 발행된 산업연관표를 이용한 원단위 DB는 없는 실정이다. 본 연구에서는 최근에 발행된 2005년, 2007년도 산업연관표를 이용하여 주요 건축자재에서 발생되는 에너지소비량 및 $CO_2$ 배출 원단위 값을 산정하고자 한다. 주요 건축자재의 에너지소비량 및 $CO_2$ 배출원단위 산출을 위한 방법은 산업연관표를 이용한 DB 구축 방식을 바탕으로 산출하였으며, 건설현장에서 주로 사용되는 16가지의 건설자재는 선별하여 적용하였다. 기존 연구결과에서 제시한 2000년도 산업연관표를 적용하여 산출된 원단위 DB 값과 비교한 결과 근소한 차이를 보이고 있어 본 연구의 산출방법이 적정한 것으로 판단하였다. 2005년, 2007년도 산업연관표를 이용하여 산출한 에너지소비량과 $CO_2$ 배출 원단위 값은 감소세를 보이고 있는 것으로 나타났으며, 시멘트와 철근을 주원료로 하는 자재에서 가장 많은 에너지소비량 및 $CO_2$ 배출 원단위 값을 나타났다. 본 연구의 결과를 통해 국내 실정에 적합한 건설자재 생산단계에서 발생되는 환경부하의 간접적인 예측이 가능할 것으로 사료된다.

• 대한기계학회논문집B
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• 제31권9호
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• pp.790-798
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• 2007

An experimental study was performed to investigate the effects of mixing quality, inlet pressure, nozzle diameter on CO, NO emission and radiation characteristics in porous ceramic fiber radiant burners. Observations of combustion characteristics occurring inside the burner system which was insulated fiber mat, were investigated by measuring emission and radiation characteristics. Combustion was achieved at the firing rate of $88{\sim}99\;kcal/hr$, inlet pressure of $100{\sim}250mmH_2O$. The fiber burner exhibit significant both spectral intensity peaks in the bands at $2.5{\mu}m\;and\;4.0{\mu}m$ relatively. There is a small difference in the variable mixing tube. However spectral intensity increased with the firing rate. CO emissions were found to be strongly dependent on the operating conditions. There was a tendency that CO concentration increased as the firing rate increases. the reason for rise of CO concentration is that is becomes it the relatively rich condition. Relatively low NO emission was observed for the whole operating range. The NO concentration is maximal at the firing rate of approximately 2850 kcal/hr and an air ratio of about 1.

• 천문학회보
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• 제38권2호
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• pp.66.1-66.1
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• 2013

We present various observational results toward a small group of Young Stellar Objects (YSOs), L1251C. Observations by Spitzer Space Telescope legacy program "From Molecular Cores to Planet Forming Disks" (c2d; Evans et al. 2003) revealed that there are three YSOs within ~15" in L1251C: IRS1 (Class I), IRS2 (Class II), and IRS3 (Class II). In order to understand the molecular environment around these YSOs, we carried out the KVN single-dish observations in $HCO^+$ J=1-0, $H^{13}CO^+$ J=1-0, $N_2H^+$ J=1-0 and HCN J=1-0. $^{12}CO$ J=1-0 was also mapped in L1251C with the TRAO 14m telescope. Integrated intensity maps of high density tracers such as $H^{13}CO^+$ J=1-0, $N_2H^+$ J=1-0 and HCN J=1-0 show similar emission distributions, whose peaks are off the positions of YSOs. A compact $HCO^+$ J=1-0 outflow and an extended $^{12}CO$ J=1-0 outflow were observed, but their outflow axes are not cosistent ($HCO^+$: NW-SE, $^{12}CO$: EW). However, the highest velocity component of the $^{12}CO$ J=1-0 outflow shows similar morphology to the $HCO^+$ J=1-0 outflow, and ~ 23 % of $^{12}CO$ outflow momentum flux is loaded onto this high velocity component. Furthermore, continuum emission has been observed at 350, 450, 850 ${\mu}m$, and 1.3mm. With the KVN single dish, the 22 GHz $H_2O$ maser emission has been also monitored toward L1251C to find variations of the systemic velocity and intensity with time.