• 천문학회지
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• 제34권1호
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• pp.17-24
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• 2001

We have studied the central parts of M82, which is a well-known infrared luminous, starburst galaxy, by analyzing archival data from the Infrared Space Observatory (ISO). M82 was observed at 11 positions covering $\pm$45" from the center along the major axis. We analyzed 4 emission lines, [ArIII] 8.99 ${\mu}m$, $H_2$ 17.034 ${\mu}m$, [FeII] 25,98 ${\mu}m$, and [SiII] 34,815 ${\mu}m$ from $SWSO_2$ data. The integrated flux distributions of these lines are quite different. The $H_2$ line shows symmetric twin peaks at $\~$18" from the center, which is a general characteristic of molecular lines in starburst or barred galaxies. This line appears to be associated with the rotating molecular ring at around $\~$200 pc just outside the inner spiral arm. The relative depletion of the $H_2$ line at the center may be due to the active star formation activity which dissociates the $H_2$ molecules. The other lines have peaks at the center and the distributions are nearly symmetric. The line profiles are deconvolved assuming that both intrinsic and instrumental profiles are Gaussian. The velocity dispersion outside the core is found to be $\~50 km s^{-1}$. The central velocity dispersion is much higher than $50 km s^{-1}$, and different lines give different values. The large central velocity dispersion ($\sigma$) is mostly due to the rotation, but there is also evidence for a high $\sigma$ for [ArIII] line. We also generated position-velocity maps for these four lines. We found very diverse features from these maps.

• 대한환경공학회지
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• 제28권12호
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• pp.1316-1322
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• 2006

본 연구는 천안 제 2산업단지에서 배출되는 대기오염물질과 악취물질을 분석하고 대기오염물질의 확산모델링을 수행하고자 함을 목적으로 한다. 측정은 12가지 지정 악취물질과 대기오염물질의 농도에 대하여 2005년 8월에 수행하였다. 악취물질은 주요 배출원을 중심으로 부지경계선에서 측정 및 분석을 실시하였으며, 대기오염물질은 ISCST3모델을 이용하여 대기오염확산 농도를 계산하였다. Air Master는 현재 국내 대기환경영향평가에 많이 사용되고 있고 U.S. EPA의 추천모델인 ISC3모델 중 ISCST3모델을 사용하였다. 따라서 천안 제 2산업단지를 대상으로 하절기 대기오염물질을 측정하여 모델링 하고 악취물질은 시료채취 후 분석을 실시하여 주변 지역에 영향을 끼치는 대기오염물질과 악취발생물질의 종류와 발생 원인을 규명하고자 한다.

• 대한환경공학회지
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• 제27권8호
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• pp.852-858
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• 2005

대기질 예측 모델링은 대기질 관리의 유용한 도구이다. 특히, 도시지역에서 대기질은 건물과 자동차와 같은 국부적인 장애물에 의해 크게 영향을 받는다. 일반적으로 도로를 따라 건물이 연속적으로 형성되어있는 도시거리협곡에서의 대기질을 예측하고자 할 때 현재 이용 가능한 대기확산모델은 대기질을 정확하게 예측하는데 많은 한계점을 가지고 있다. 본 연구에서는 도시거리협곡에서 대기질 예측을 위한 경험적인 모델을 제안하고자 하였다. 이를 위해 풍동실험을 수행하고, 그 결과를 통계적으로 분석하였다. 풍동실험 결과 넓은 협곡인 경우와 도로축과 직각을 이루는 바람일 때 도시거리협곡의 대기질을 향상시키는데 유용하다는 것을 확인하였다. 또한, 제안한 모델을 이용한 모델 예측치는 풍동실험 결과와 상관성이 양호하게 나타났다.

• 대한교통학회지
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• 제35권1호
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• pp.37-49
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• 2017

본 연구에서는 도로이동오염원을 대상으로 추진하는 교통환경정책의 대기질 개선효과 분석 방법론을 제시하였으며, 해당 방법론은 정책 추진에 따른 도로이동오염원의 통행량과 대기오염물질 배출량 변화, 대기오염물질의 공간적 확산과 이로 인한 노출인구의 건강영향을 순차적으로 고려한다. 특히 도로이동오염원의 통행량 변화는 정책 효과와 직접적인 연관이 있기 때문에 대기질 개선효과 분석시 반드시 고려되어야 하며, 본 연구에서는 교통수요모형 기반의 상향식 방법을 적용하여 기존 하향식 방법 대비 정책 추진에 따른 통행자의 통행행태 변화를 상세하게 반영하고자 하였다. 정책 시나리오 분석을 통하여 본 연구에서 제시한 분석 방법론의 활용가능성을 검토하였으며, 통행자의 통행행태 변화가 예상되는 정책의 대기질 개선효과 분석은 본 연구의 분석 방법론 적용이 필요한 것으로 판단된다.

• 한국대기환경학회지
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• 제8권4호
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• pp.213-220
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• 1992

Simple correlation analysis, factor analysis, and multi-variate analysis have been performed to analyze the relationship between air pollution and meteorological factors for air pollution and meteorological data measured at Kwanghwamun in Seoul during the period of one year(January 1990 $\sim$ December 1990). As a result of simple correlation and factor analysis, $SO_2$, TSP and CO concentrations have shown high negative correlation with temperature and among these indicating that these are related with pollutant emission trend based upon heating fuel usage. Ozone has a good corrleation with solar radiation and relative humidity to have a closed relation with $O_3$ generation reaction mechanism. The result of multi-variate correlation analysis shows that the concentration of $SO_2$ and CO are adequate for correlation model with ambient temperature and wind speed and $O_3$ concentrations are adequate for that with solar radiation and wind speed. $SO_2$ and CO levels are considered to be affected first of all by heating fuel usage as a emssion source and wind speed as a dispersion effect. The $SO_2$ concentration in the condition that the temperature fall below zero is explained by multilicative model with wind speed, only one variable.

• Journal of Astronomy and Space Sciences
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• 제27권4호
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• pp.309-318
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• 2010

We introduce a technical approach for reducing three-dimensional infrared (IR) spectroscopic data generated by integral field spectroscopy or slit-scanning observations. The first part of data reduction using IRAF presents a guideline for processing spectral images from long-slit IR spectroscopy. Multichannel image reconstruction, Image Analysis and Display (MIRIAD) is used in the later part to construct and analyze the data cubes which contain spatial and kinematic information of the objects. This technic has been applied to a sample data set of diffuse 2.1218 ${\mu}m$ $H_2$ 1-0 S(1) emission features observed by slit-scanning around Sgr A East in the Galactic center. Details of image processing for the high-dispersion infrared data are described to suggest a sequence of contamination cleaning and distortion correction. Practical solutions for handling data cubes are presented for survey observations with various configurations of slit positioning.

• 천문학회보
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• 제39권2호
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• pp.65.1-65.1
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• 2014

We present Palomar/SWIFT integral field spectroscopy of z~0.2 strong $H{\alpha}$ emitters identified in the Sloan Digital Sky Survey. The large Halpha equivalent widths as well as the huge specific star formation rates of these galaxies are comparable with that of z>4 Lyman break galaxies, thus understanding the gas kinematics and the distribution of massive stars in these systems will help to obtain a better understanding of high-redshift star forming environments and the growth of massive galaxies. We measure the velocity dispersion across the entire galaxy, estimate the number density and the spatial distribution of massive stars from the emission line morphologies. The role of minor mergers in powering star formation is investigated as an alternative to cold flow driven star formation.

• 한국전기전자재료학회논문지
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• 제23권4호
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• pp.338-342
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• 2010

Carbon nanotubes (CNTs) have excellent electrical, chemical stability, mechanical and thermal properties. The MWCNT films were investigated as a transparent electrode for the solar cell, OLED, and field-emission display. MWCNT films were fabricated by air spray method, whose process is quite low-costed, using the multi-walled CNTs solution on glass substrates. Moreover, the most stable film was fabricated when the spraying time was 60 sec. The film that was sprayed with the MWCNT dispersion for 60 sec, has 300nm thick. And its electric resistivity, transmittance rate, mobility and carrier concentration are $6{\times}10^{-2}{\Omega}{\cdot}cm$, 50% at ${\lambda}=550mm$, $4.3{\times}10^{-2}cm^2/V{\cdot}s$ and $2.1{\times}10^{21}cm^{-3}$, respectively. Also, absorption energy of MWCNT films show from 3.9 eV to 4.6 eV. Furthermore, we can use MWCNT films fabricated by the spray method for the transparent electrode.

• 한국대기환경학회지
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• 제21권6호
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• pp.573-583
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• 2005

Fugitive dust, which is emitted in the ambient air without first passing through a stack or duct designed to control flow, is frequently generated by means of wind erosion from storage yards at Pohang Steel Wokrs. The size distribution of fugitive dust is mostly in the range of coarse particulate which is deposited as soon as emitted and less harm to human health; however $20\%$ of fugitive dust contains PM 10 known as one of most harmful airborne pollutant. Consequently, effective control and reduction of fugitive dust is strongly requested by the local society, but it is not easy so far because the generation and dispersion of fugitive dust highly depends on meteorological conditions, and it being occurred for irregularity. This research presented a fugitive dust control system for each meteorological condition by providing statistical prediction data obtained from a statistical analysis on the probability of generating the threshold velocity at which the fugitive dust begins to occur, and the frequency occurring by season and by time of the wind direction that can generate atmospheric pollution when the dispersed dust spreads to adjacent residential areas. The research also built a fugitive dust detection system which monitors the weather conditions surrounding storage yards and the changes in air quality on a real-time basis and issues a warning message by identifying a situation where the fugitive dust disperses outside the site boundary line so that appropriate measures can be taken on a timely basis. Furthermore, in respect to the spraying of water to prevent the generation of fugitive dust from the storage piles at the storage yard, an advanced statistical meteorological analysis on the weather conditions in Pohang area and a case study of fugitive dust dispersion toward outside of working field during $2002\∼2003$ were carried out in order to decide an optimal water-spraying time and the number of spraying that can prevent the origin of fugitive dust emission. The results of this research are expected to create extremely significant effects in improving surrounding environment through actual reduction of the fugitive dust produced from the storage yard of Pohang Steel Works by providing a high-tech warning system capable of constantly monitoring the leakage of fugitive dust and water-spray guidance that can maximize the water-spraying effects.

• 한국분말재료학회지
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• 제23권6호
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• pp.409-413
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• 2016

Electrical wire explosion in liquid media is a promising method for producing metallic nanopowders. It is possible to obtain high-purity metallic nanoparticles and uniform-sized nanopowder with excellent dispersion stability using this electrical wire explosion method. In this study, Ni-Fe alloy nanopowders with core-shell structures are fabricated via the electrical explosion of Ni-Fe alloy wires 0.1 mm in diameter and 20 mm in length in de-ionized water. The size and shape of the powders are investigated by field-emission scanning electron microscopy, transmission electron microscopy, and laser particle size analysis. Phase analysis and grain size determination are conducted by X-ray diffraction. The result indicate that a core-shell structured Ni-Fe nanopowder is synthesized with an average particle size of approximately 28 nm, and nanosized Ni core particles are encapsulated by an Fe nanolayer.