• The Bulletin of The Korean Astronomical Society
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• v.35 no.1
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• pp.69.2-69.2
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• 2010

The far-ultraviolet (FUV) H2 and C IV emission images and spectra of Orion Eridanus Superbubble (OES) is hereby presented. The OES seems to consists of multiple phase through the detection of highly-ionized gas and pervasive neutral hydrogen. The former is traced by hot gas while the latter is traced by cold medium. A spectral image made with H2 fluorescent emission shows that the spatial distribution of hydrogen molecule is well correlated with the dust map. The model spectra was taken from a photodissociation region (PDR) radiation code which find a best suitable parameter such as hydrogen density, gas temperature and incident uv intensity of the radiation field. C IV emission is caused by intermediate temperature ISM about 10^4.5 K~10^6 K. Therefore we could get more clear evidence to reveal the structure of OES. Feature of spectra for the each sub region is also presented and discussed. The data were obtained with the Far-Ultraviolet Imaging Spectrograph (FIMS) and the whole data handling were followed by previous FIMS analysis.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.2
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• pp.71.1-71.1
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• 2010

The far-ultraviolet (FUV) C IV and H2 emission spectra of Orion-Eridanus Superbubble (OES) is hereby presented. The OES seems to consist of multiple phase through the detection of highly-ionized gas and pervasive neutral hydrogen. The former is traced by hot gas while the latter is traced by cold medium. A spectral image made with H2 fluorescent emission shows that the spatial distribution of hydrogen molecule is well correlated with the dust map. The model spectra was taken from a photodissociation region (PDR) radiation code which finds a best suitable parameter such as hydrogen density and intensity of the radiation field. C IV emission is caused by intermediate temperature ISM about 10^5 K. Therefore we could get more clear evidence to reveal the morphology of OES. In this process, the hydrogen density and gas temperature were also estimated. The data were obtained with the Far-Ultraviolet Imaging Spectrograph (FIMS) and the whole data handling were followed by previous FIMS analysis.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2001.11a
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• pp.185-186
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• 2001

미세입자의 배출원을 추정하기 위해서는 수용지점에 영향을 미칠 수 있는 배출원의 화학적 특성에 관한 정보를 필요로 한다. 수용모델(chemical mass balance model, CMB)의 경우, 모델수행에 필요한 정보는 각각의 배출원에서 배출되는 입자의 화학적 구성성분특성을 파악하는 것이 가장 중요하다(Waton et al., 1984; U. S. EPA, 1987; 강병욱 등, 2000) 이러한 배출원으로는 각종 산업배출원, 자동차, 토양, 도로 비산먼지 등 지역의 특성에 따라서 다양한 배출원들이 대상이 될 수 있다. (중략)

• Proceedings of the KSRS Conference
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• 1998.09a
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• pp.404-408
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• 1998

Yellow sand event has been studied using SeaWiFS data in order to examine the aerosol optical characteristics in the Yellow Sea and their influences on the atmospheric correction for the ocean color remote sensing. Two SeaWiFS images of April 18 and April 25, 1998, representing Yellow Sand event and clear-sky case respectively, are selected for emphasizing the impact of high aerosol concentration on the ocean color remote sensing. It was shown that NASA's standard atmospheric correction algorithm treats yellow sand area as either too high radiance or cloud area, in which ocean color information is not generated. SeaWiFS aerosol optical thickness is compared with nearby ground-based sun photometer measurements and also is compared with radiative transfer simulation in conjunction with yellow sand model, examining the performance of NASA's atmospheric correction algorithm in case of the heavy dust event.

• Journal of Astronomy and Space Sciences
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• v.10 no.1
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• pp.25-35
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• 1993

Stars lose their masses constantly after their birth, but the stellar mass loss is especially prominent in the last stages of their lives. It has been believed that red superginats are losing their masses at rates of 10-8∼10-4M/yr. They are known to be asymptotic giant branch stars that are at the end stages of the evolution for the stars with zero age main sequence masses of 1∼10M. Red supergiants are often characterized by the thick dust envelopes and large amplitude pulsations. According to their energy spectra, chemical composition, they are divided into three main group; M-type Miras, C-type carbon stars, and OH/IR stars. The purpose of this work is to clarify the evolutionary aspects in the physical parameters of the red supergiants mainly from the direct interpretation of their infrared spectra.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.1
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• pp.50.1-50.1
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• 2013

As part of the DIGIT key program, we observed GSS30-IRS1, a Class I object located in Ophiuchus (d=125 pc), with Herschel-PACS. More than 70 lines were detected: CO lines of $J=14{\rightarrow}13$ to $41{\rightarrow}40$, several $H_2O$ lines of Eu=100 to 1500 K, 16 OH lines, and two atomic [OI] lines at 63 and 145 ${\mu}m$. All lines, except for [OI], were detected only at the central spaxel of $9.4^{\prime\prime}{\times}9.4^{\prime\prime}$ while the [OI] emission is extended along the NE-SW direction. One interesting feature in GSS30-IRS1 is that the continuum is extended beyond PSF, unlike the line emission. For detail analysis, we apply the non-LTE LVG model, RADEX as well as simple rotational diagrams to the detected line fluxes. We will discuss about the physical conditions around GSS30-IRS1, learned by the line flux analysis.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.39.2-39.2
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• 2016

The central regions of barred-spiral galaxies contain interesting gaseous structures such as dust lanes located at the leading side of the bar and nuclear rings that are sites of intense star formation. Our previous studies showed how gas structures form under the influence of a non-axisymmetric bar potential and temporal/spatial behavior of the star formation in nuclear rings. However, previous works were limited to 2-dimensional infinitesimally-thin, unmagnetized and isothermal disks. To study effects of cooling/heating, vertical motions of gas structures and magnetic field, we use Mesh-Free magneto-hydrodynamic simulation code GIZMO. We find that temporal variations of the star formation rates in the nuclear ring in the three-dimensional model are overall similar those in the previous two-dimensional results, although the former shows more violent small-scale fluctuations near the early primary peak. We will present our recent results about evolution of gaseous structures and star formation rate compare with results of previous studies.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.72.3-72.3
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• 2016

A massive envelope and a strong bipolar outflow are the two most distinct structures of youngest protostellar systems. We present observational results from the Combined Array for Research in Millimeter-wave Astronomy (CARMA) toward the youngest (Class 0) protostellar system L1157. At an angular resolution of 5 arcseconds, we mapped its well-developed outflow in CO 2-1 over a span of approximately 5 arcminutes. Additionally, we imaged the central envelope with CO isotopes, CS, CN, and N2H+ with an angular resolution of about 2 arcseconds. We show that the bipolar outflow may be represented with a two jet model and constrain its physical properties such as precession/rotation directions, velocities, inclinations, and position angles via cube data fitting. In addition, we discuss the kinematic features of the envelope detected in CO isotopes and N2H+ and present the radius-dependent dust opacity spectral index.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.11
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• pp.632-639
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• 1999

SRM(Switched Reluctance Motor) drives require the accurate position and speed information of the rotor. These informations are generally provided by a shaft encoder or resolver. High temperature, EMI, and dust may make detection performance deteriorate. Therefore, the elimination of the position and speed sensor is desirable. In this paper, a nonlinear adaptive observer using the MRAS(Model Reference Adaptive System) is proposed. The rotor speed and position are estimated by the adaptation law using the real and estimated currents. The stability of the adaptive observer is proved by Lyapunov stability theory. The proposed methods are implemented with TMS320C31 DSP. Experimental results prove that the observer has a good estimation performance of the rotor speed and position despite of the parameter variations and loads, and the speed control can be accomplished in the wide speed range.

• Journal of Korean Society of Rural Planning
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• v.25 no.3
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• pp.11-18
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• 2019

It is widely known that agricultural plastic waste incineration by farmers may cause big forest fire or fine dust in rural areas. Hence, how to increase the rate of collection and recycling of the agricultural plastic waste is of concern to policy makers especially for rural environment. The purpose of this study is to find the determinants of the collection rate of agricultural plastic waste. This study used the data from 'Research on Agricultural Waste' by the Korea Environment Corporation from year 2012 to 2015 for 163 regions. This study found that the compensation rate for collection, the frequency of collecting services, and the quality of waste are important to increase the collection rate. And the regions with more elderly and low income people are more likely to have higher collection rate. Finally, the chief producing regions that are specialized in a certain crop shows higher collection rate.