• 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.

• 천문학회지
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• 제35권2호
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• pp.105-110
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• 2002

We present the results of VLA $NH_3$ (1,1) and (2,2) line observations of the young-stellar object (YSO) IRAS 19550+3248. The integrated intensity map of the $NH_3$ (1,1) line shows that there are two ammonia cores in this region; core A which is associated with the YSO, and core B which is diffuse and located at the northeast of core A. Core A is compact and elongated along the east-west direction (0.07 pc$\times$0.05 pc) roughly perpendicular to the molecular outflow axis. Core B is diffuse and extended (0.18 pc$\times$0.07 pc). $NH_3$ (2,2) line is detected only toward core A, which indicates that it is hotter (~ 15 K), presumably due to the heating by the YSO. The $NH_3$ (1,1) line toward core A is wide (${\Delta}v{\ge} 3 km s^{-l}$) and appears to have an anomalous intensity ratio of the inner satellite hyperfine lines. The large line width may be attributed to the embedded YSO, but the hyperfine anomaly is difficult to explain. We compare the results of $NH_3$ observations with those of previous CS observations and find that the CS emission is detected only toward core A and is much more extended than the $NH_3$ emission.

• 천문학회보
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• 제40권2호
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• pp.53.2-53.2
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• 2015

We present preliminary results from a series of observations toward G108.8-00.8, which is one of Planck Cold Clumps and a promising candidate of massive prestellar cores. In the integrated intensity map of SCUBA 850 micron dust continuum emission, highly fragmented structures appear. These are distributed along one long filamentary structure seen in the CO 1-0 and 13CO 1-0 integrated intensity maps obtained with the PMO 13.7 m telescope. The northern part of the filament is divided into two parts, as seen in the CO 2-1, 13CO 2-1, and C18O 2-1 integrated intensity maps obtained with the CSO 10 m telescope. The observations of HCO+ 1-0, N2H+ 1-0, and HCN 1-0 with the IRAM 30 m telescope focus on the northern part of the CSO maps, which show a head-tail structure. NH3 (1,1) also shows similar distribution with IRAM maps. The depletion factors, derived by the comparison between the dust continuum and C18O 2-1 emission, varies from 1.5 to 6 over the region, suggesting different evolutionary status of each component. To study the chemical and physical environments of G108.8-00.8, more detailed analysis is in progress.

• International Journal of Automotive Technology
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• 제6권4호
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• pp.333-340
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• 2005

In order to better quantify the contribution from nonroad sources to emission inventories, it is important to understand not only the emissions rates of these engines but also activity patterns that can be used to accurately portray their in-use operation. To date, however, very little information is available on the actual activity patterns of nonroad equipment. In this study, a total of 18 pieces of nonroad equipment were instrumented with collected data including intake manifold air pressure (MAP), exhaust temperature and, on a subset of vehicles, engine rpm and throttle position. The equipment included backhoes, compactors, dozers, motor graders, loaders and scrappers used in applications such as landfilling, street maintenance and general roadwork. The activity patterns varied considerably depending on the type of equipment and the application. Daily equipment operating time ranged from less than 30 minutes to more than 8 hours, with landfill equipment having the highest daily use. The number of engine starts per day ranged from 3-11 lover the fleet with an average of 5 starts per day. The average percent idle time for the fleet was approximately $25\%$ with a range from 11 to $65\%$ for individual pieces of equipment. Duty cycles based on exhaust temperature/throttle position profiles were also developed for two graders and one dozer.

• 천문학회보
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• 제35권1호
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• pp.28.2-28.2
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• 2010

We have investigated seven Extreme-Ultraviolet (EUV) bright points in the active region (AR 10926) on 2006 December 2 by the EUV imaging spectrometer (EIS) onboard Hinode spacecraft. We determined their Doppler velocities and non-thermal velocities from 15 EUV spectral lines (log T=4.7-7.2) by fitting each line profile to a Gaussian function. We present the Doppler velocity map as a function of temperature which corresponds to a different height. As a result, these active region bright points show two different types of characteristics. Type 1 bright point shows a systematic increase of Doppler velocity from -68 km/s (blue shift) at log T=4.7 to 27 km/s (red shift) at log T=6.7, while type 2 bright points have Doppler velocities in the range of -20 km/s and 20 km/s. Using MDI magnetograms, we found that only type 1 bright point was associated with the canceling magnetic feature at the rate of $2.4{\times}10^{18}$ Mx/hour. When assuming that these bright points are caused by magnetic reconnection and the Doppler shift indicates reconnection out flow, the pattern of the Doppler shift implies that type 1 bright point should be related to low atmosphere magnetic reconnection. We also determined electron densities from line ratio as well as temperatures from emission measure loci using CHIANTI atomic database. The electron densities of all bright points are comparable to typical values of active regions (log Ne=9.9-10.4). For the temperature analysis, the emission loci plots indicate that these bright points should not be isothermal though background is isothermal. The DEM analysis also show that while the background has a single peak distribution (isothermal), the EUV bright points, double peak distributions.

• 천문학회보
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• 제41권1호
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• pp.49.2-49.2
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• 2016

MIRIS Paschen-${\alpha}$ ($Pa{\alpha}$) Galactic Plane Survey (MIPAPS) presents the first whole Galactic plane (with the width of $-3^{\circ}$ < b < $+3^{\circ}$) map for the $Pa{\alpha}$ emission line. Many of $Pa{\alpha}$ features were detected more brightly than the previous observed $H{\alpha}$ features, and they coincide well with dense cloud regions. This means that newly detected $Pa{\alpha}$ blobs can indicate massive star forming regions (H II regions) screened by foreground clouds around Galactic plane. Anderson et al. (2014) presented the most complete Galactic H II region catalog based on WISE 12 and 22 um data. Of the cataloged sources, only ~20% have measured radio recombination line (RRL) or $H{\alpha}$ emission, and the rest are still candidate H II regions. At first, we compare the MIPAPS results with Anderson's H II region catalog for the Cepheus region (Galactic longitude from $+96^{\circ}$ to $116^{\circ}$). From this, we will investigate how much MIPAPS can supplement the catalog, and show MIPAPS scientific potential. After that, we plan to extend this work to the whole plane, and finally catalog MIRIS $Pa{\alpha}$ blob sources for the whole Galactic plane.

• 한국지형학회지
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• 제21권4호
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• pp.121-131
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• 2014

이 연구에서는 카올리나이트의 분광반사 특성과 ASTER(Advanced Spaceborne Thermal Emission and Reflectance Radiometer) 영상 자료를 이용하여 경상남도 하동지역 고령토 광산의 분포를 추출하였다. ASTER 영상의 광물별 파장 흡수 밴드특성을 이용하여 고령토 광상의 주 구성 광물인 카올리나이트의 분포 양상을 추출하기 위해서 밴드 비연산 모델을 적용하였다. 분광반사 특성 곡선에 따르면 카올리나이트는 Al-OH에 의해서 0.96과 $2.18{\mu}m$ 파장 인근에서 흡수특성이 나타나며, $1.24{\mu}m$와 $1.38{\sim}1.41{\mu}m$에서 OH의 영향을 받는다. 이러한 카올리나이트 분광특성을 ASTER 영상에 적용하여 현재 개발 중인 고령토 광산을 포함하여 채굴적 등의 분포를 판독하였다.

• 한국수소및신에너지학회논문집
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• 제33권6호
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• pp.636-642
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• 2022

The "Hydrogen Economic Activation Road map" was announced in 2019, and hydrogen demand is expected to exceed 470,000 tons per year in 2022 and keep increasing. Under this circumstance, it has become important to understand the greenhouse gas (GHG) emissions associated with various hydrogen production pathways. In this study, the evaluation of life cycle GHG emissions regarding the hydrogen produced as by-product from coke oven gas (COG) in steel mill is conducted. To cover the possible range of operations, three literatures were reviewed and their data of inputs and outputs for the process were adopted for calculation. Life cycle inventories and emission factors were mostly referred to GaBi and Intergovernmental Panel on Climate Change (IPCC) guidelines, respectively. When there are multiple products from a single process, the energy allocation method was applied. Based on these sources and the assumptions, the life cycle emission values of COG-based hydrogen were found to be 3.8 to 4.7 kg/CO₂-eq./kg-H₂.

• 한국농림기상학회지
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• 제25권1호
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• pp.48-59
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• 2023

본 연구에서는 새롭게 개발된 식생의 BVOCs 배출계수를 기반으로 MEGANv2.1을 구동 후 BVOCs 배출량을 산출하여 질소산화물과의 결합을 통해 대류권 오존농도에 어떠한 영향을 미치는지 분석하고 그에 대한 신뢰성을 검토하고자 한다. BVOCs 대상물질은 이소프렌(Isoprene)과 모노테르펜(Monoterpenes)으로 한정하였고, 모델링 도메인의 공간적 범위는 남한지역을 포함하는 한반도의 남부(위도 : 32.8N~39.3N, 경도 : 123.4E~130.9E)와, 시간은 2008년 5월 1일부터 6월 30일까지를 대상으로 하였다. 식생 BVOCs 배출 모델의 입력자료를 생성하기 위해 토지피복 자료는 MODIS (MODerate resolution Imaging Spectroradiometer)의 MCD12Q1 (Land Cover type 5, PFT)와 환경부의 중분류 토지피복도를 사용하였고, 엽면적지수 자료는 MODIS의 MCD15A2를 사용하였다. 또한, 인위적 활동에 의한 배출량을 산출하기 위해 사용된 모델은 SMOKE-Asia 1.20 버전(Woo et al., 2009)이며, 오존농도를 모의하기 위해 CAMx v6.0 모델을 사용하였다. 연구의 진행은 1) 기존에 우리나라에서 측정된 식생 배출 값들을 조사하여 새로운 식생 배출계수를 BVOCs 배출모델에 적용하고, 2) GIS S/W을 이용하여 식생 배출모델(MEGAN)에 사용되는 입력자료를 생성하고, 3) MEGANv2.1을 구동하여 식생 배출량을 산출하고, 4) 인위적 배출을 산출하는 모델(SMOKE-Asia)을 구동하여 나온 인위적 배출량과 식생 배출량을 결합하여 대기화학 수송 모델(CAMx)의 입력자료로 사용하고, 5) 대기화학 수송 모델에서 구동된 오존농도의 결과 값을 실제 측정 값과 비교하여 식생 배출량 결과의 적정성에 대해 검토하였다. CAMx 모델을 통해 5개의 시나리오(인위적+식생 VOCs 배출 시나리오 4개 : A, B, C, D / 인위적 VOCs 배출 시나리오 1개 : E)에 대해 오존 생성농도를 비교한 결과, 본 연구에서 새롭게 적용한 식생 배출계수와 MODIS PFT를 사용한 시나리오 C에서 오존농도가 가장 높게 모의되었고, 인위적 VOCs 배출만을 고려한 시나리오 E보다 지역별로는 최대 53ppb, 도메인 평균으로는 2ppb 정도 높게 오존농도를 모의하고 있었다. 배출계수와 토지피복지도의 변화로 인한 오존농도의 차이 중에서는 배출계수의 변화로 인한 오존농도의 변화가 더 큰 것으로 확인되었다. 오존농도에 대해 모델링한 결과를 6개 도시지역의 오존 측정망 값과 비교한 결과, 자연적 VOCs 배출량이 상대적으로 작은 대도시와 주변 도시지역에서는 시나리오에 따른 모델과 측정 값과의 결정계수 값의 변화가 작게 나타났고, 자연적 VOCs 배출량이 높은 중소 도시지역에서는 시나리오에 따른 모델과 측정 값과의 결정계수 변화가 높게 나타났다.

• 대한원격탐사학회지
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• 제27권1호
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• pp.43-49
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• 2011

지구온난화의 주범인 이산화탄소가 국제적으로 문제가 되고 있는 가운데, 이산화탄소의 농도 증가를 억제시키기 위해 이산화탄소를 포집하여 장기간 안정적으로 저장시킬 수 있는 탄소 포집 및 저장(Carbon Capture and Storage: CCS) 기술의 개발이 요구되고 있다. CCS 기술은 이산화탄소 저감 방안 중 가장 직접적이고 현실적인 방안으로 각광을 받고 있으나, 이산화탄소 최적 저장지의 선정 및 이산화탄소 지중저장이 야기할 수 있는 부수적인 영향에 대한 분석이 요구된다. 본 연구에서는 경상분지를 대상으로 GIS 기법을 이용하여 CCS 설비를 위한 적지 분석을 수행하고, 현황분석 및 법적분석을 수행하였다. 적지분석에는 지질도, 수치표고모형, 경사도, 토지피복도를 이용한 경중률 분석이 사용되었으며, 현황분석에는 고해상도 위성영상을 활용하였다. 그 결과 연구대상지내 이산화탄소 저장시설 설치를 위한 최적후보지가 선정되었으며, 마지막으로 법적분석에서는 탄소 저장과 관련된 현행 규정 및 탄소 저장시설의 설비 시 문제가 될 수 있는 각종 법적 사항을 조사하였다.