• 한국대기환경학회지
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• 제9권3호
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• pp.255-256
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• 1993

Recently, Ghim and Son (1993) compared the air quality impacts of two point sources P1 and P3 in Seoul in the first quarter of 1988, whose emission rates were 99.9g/s and 49.4g/s, and whose stack heights were 75m and 21m. They said that higher concentrations from P3 in the nearby area were responsible for shorter stack height of P3. But concentrations were not raised so high only because the stack height was reduced from 75m to 21m. Volume of exit gas from P3 was also much smaller than that from P1.

• 한국광학회:학술대회논문집
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• 한국광학회 2009년도 창립 20주년기념 특별학술발표회
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• pp.323-324
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• 2009

In this paper, we use multi-point sources to illuminate the sample in digital holographic microscopy. The resolution of digital holographic microscopy is enhanced without shifting the CCD camera. The specimen is illuminated from many directions by using multi-point sources which are easily created by a lens-array. The high frequency information of specimen can be captured at a fixed position of CCD camera. All information is then synthesized to increase the resolution.

• 한국관개배수논문집
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• 제14권2호
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• pp.181-193
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• 2007

The characteristics of non-point source pollutant loads in middle-stream of Nakdong River Were studied through analysis of pollutant loads of 8 sub-watersheds divided based on administrative district. The pollutant concentration of each sub-watershed was collected from Nakdong-River Water Research Institute and Daegu Regional Environmental Office, respectively. Pollution items analysed in this study were BOD, SS, T-N and T-P. High degree of non-point pollution was observed from Gumi, Goryeong, Gyeongsan, Daegu and Sungju, and pollution was usually increased during rainy season. This result indicates that a given pollution condition within the watershed can be more sensitive than location factor to the level of water quality. The main sources of non-point pollution were population and livestock, as well as landuse factor, and were found to significantly contribute to the water pollution. Alternative solutions for controlling pollution sources, therefore, should be provided to meet target levels of water quality in this region.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.96-99
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• 2003

Land cover map is a typical GIS database which shows the Earth's physical surface differentiated by standardized homogeneous land cover types. Satellite images acquired by Landsat TM were primarily used to produce a land cover map of 7 land cover classes; however, it now becomes to produce a more accurate land cover classification dataset of 23 classes thanks to higher resolution satellite images, such as SPOT-5 and IKONOS. The use of the newly produced high resolution land cover map of 23 classes for such activities to estimate non-point sources of pollution like water pollution modeling and atmospheric dispersion modeling is expected to result a higher level of accuracy and validity in various environmental monitoring results. The estimation of pollution from non-point sources using GIS-based modeling with land cover dataset shows fairly accurate and consistent results.

• 천문학회보
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• 제46권2호
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• pp.66.2-66.2
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• 2021

We list up the Paα-emitting sources observed in the Carina Region (l = 276°-296°) using the MIRIS Paα Galactic Plane Survey data. A total of 201 sources are cataloged. Out of them, 118 sources are coincident with those in the WISE H II region catalog. 52 H II region candidates are newly confirmed as definite H II regions by detecting the Paα recombination lines. For the remaining 83 sources, we search the corresponding objects in the SIMBAD database. 26 point-like sources are associated with planetary nebulae or emission-line stars (such as Wolf-Rayet and Blue supergiant stars). Also, we carry out aperture photometry to measure Paα fluxes for the sources that show circular features without overlapping with other bright sources. For the whole Galactic Plane, the complete Paα-emitting source catalog is in progress.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.383-383
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• 2011

Generally, field emitters can be categorized into two types according to the emitter shape, one is a planar field emitter and the other is a point emitter. The planar field emitter is used for displays, flat lamps and signage boards. On the other hands, the point field emitter is expected to play a significant role in x-ray sources and electron beam sources. Such applications of the point field emitters, especially, need large emission current and high emission stability with a small electron beam size. A few reports announced point emitters made by carbon nanotubes (CNTs). However, they still have suffered from poor reproducibility and low emission current. Here, we demonstrated high performance CNT point emitters by attaching CNTs onto graphite rod. Graphite rod exhibited good electrical conductivity and chemical stability. In this method, the shape of the point emitter could be easily controlled by changing the length and diameter of the graphite rod. The CNT point emitter showed emission current over 1 mA at an applied electric field of 1.4 V/${\mu}m$. We consider that the stable emission performance is attributed to the stable contact between CNTs and graphite rod.

• 천문학회지
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• 제52권1호
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• pp.1-9
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• 2019

We present the results of the spectral and temporal analysis of eight X-ray point sources in five nearby (distance < 20 Mpc) galaxies observed with Chandra. For spectral analysis, an absorbed powerlaw and an absorbed diskblackbody were used as empirical models. Six sources were found to be equally fitted by both the models while two sources were better fitted by the powerlaw model. Based on model parameters, we estimate the X-ray luminosity of these sources in the energy range 0.3 - 10.0 keV, to be of the order of ${\sim}10^{39}ergs\;s^{-1}$ except for one source (X-8) with $L_X>10^{40}ergs\;s^{-1}$. Five of these maybe classified as Ultraluminous X-ray sources (ULXs) with powerlaw photon index within the range, ${\Gamma}{\sim}1.63-2.63$ while the inner disk temperature, kT ~ 0.68 - 1.93 keV, when fitted with the disk blackbody model. The black hole masses harboured by the X-ray point sources were estimated using the disk blackbody model to be in the stellar mass range, however, the black hole mass of one source (X-6) lies within the range $68.37M_{\odot}{\leq}M_{BH}{\leq}176.32M_{\odot}$, which at the upper limit comes under the Intermediate mass black hole range. But if the emission is considered to be beamed by a factor ~ 5, the black hole mass reduces to ${\sim}75M_{\odot}$. The timing analysis of these sources does not show the presence of any short term variations in the kiloseconds timescales.

• 대한환경공학회지
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• 제36권1호
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• pp.13-19
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• 2014

청정한 물환경에 대한 기대가 높아지는 시대에서, 관리가 쉽지 않은 비점오염원에서 발생하는 오염부하량을 산정하여 합리적인 국토관리를 도모할 수 있는 기초자료를 제시하였다. 연구는 2개소의 밭경작지를 대상으로 하였으며 고구마와 벚나무를 재배하는 비점오염원으로 각각 3년 동안에 걸쳐 강우사상을 모니터링 하였다. 오염부하량에 영향을 미치는 가장 중요한 인자는 강우량으로 50 < rainfall (mm)의 강우사상에서는 100% 강우유출량이 발생하여 오염물질을 발생하였다. 그러나 30 < rainfall (mm) ${\leq}50^a$와 10 < rainfall (mm) ${\leq}30^b$에서는 강우유출수에 의한 오염부하에는 작물의 재배방법과 토양의 특성 등이 결정인자로 작용되어, 작물성장이 현저한 벚나무경작지에서 강우유출수 발생빈도는 a : 60%, b : 5%로 고구마경작지에서의 강우유출수 발생빈도보다 낮았으며, 이로 인해 오염부하량도 적었다. 반면, 고구마경작지에서의 강우유출수 발생빈도는 a : 80%, b : 15%로 나타났다.

• 한국도로학회논문집
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• 제14권1호
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• pp.55-61
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• 2012

본 연구는 도시지역 도로측구 등에 설치할 비점오염원의 정화장치 개발을 위해 여과재의 개발에 연구의 초점을 맞추었다. 필터는 다양한 미세기공을 갖고 있어 물리적 흡착능력이 뛰어나며, 결정 구조 안에 다양한 양이온이 배위되어 있어 화학적 흡착이 탁월한, 다공성 점토광물을 직경 3mm 볼 형태로 제작하였다. 성형한 필터에 도시지역 강우 직후 발생한 오염 원수를 통과시켜 SS, COD, T-P, T-N의 제거 능력을 폐수정화에 흔히 이용되는 첨착활성탄(Impregnated Activated Carbon) 필터와 비교 분석하였다. 다공성 점토광물 필터와 첨착활성탄 필터의 T-N과 T-P 여과능력은 거의 차이가 없음을 알 수 있었다.

• 한국환경과학회지
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• 제29권12호
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• pp.1249-1260
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• 2020

Non-point source pollutants have characteristics the render them difficult to manage owing to the uncertainty of flow paths. As agricultural non-point sources account for more than 57% of non-point source pollutants, the necessity for management is increasing. This study examines the possibility of utilizing land cover maps to suggest a more appropriate method of setting management priority for agricultural non-point sources in the Daecheong Lake area and draws implications by comparing the results derived using the cadastral map, as mentioned in the TMDL Basic Policy. To define the prioritized areas for management, the pollution load was calculated for each subbasin using the formula from the TMDL technical guidelines. As a result, the difference in the average pollution load between the land cover map and cadastral map ranged from 11.6% to 21% among the subbasins. In almost all subbasins, there were differences in the ranking of management priorities depending on the land information that was used. In addition, it was found that it was reasonable to use the level 3 land cover map to calculate the load generated by the land system for examining the implementation goals and methods of each data and comparing them with satellite images.