• Title/Summary/Keyword: outflows

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A Study on the Flood Routing using a Convective-Diffusion Model (대류-확산 모델을 이용한 홍수추적에 관한 연구)

  • 남선우;박상우
    • Water for future
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    • v.18 no.3
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    • pp.265-270
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    • 1985
  • The prediction of a design-flood hydrograph at a particular site on a river may be based on the derivation of discharge or stage hydrograph at an upstream section, togeater with a method to route this hydrograph along the rest of river. On the other hand, flood routing methods provide a useful tool for the analysis of flooding in all but the smaller catchment, and these methods are largely stored into hydrological method and hydraulic method. Although the Muskingum Method as a hydrological method ignores dynamic effects on the flood wave, Muskingum-Cunge Method based on hydraulic method is possible to improve the method so that it gives a good approximation to the solution of the linear convective-diffusion equation. This is made on the basis of the finite diffeience equation for the Muskingum Method. In the study, the outflows predicted by Muskingum-Cunge Method are campared with the observed outflows of the Pyung Chang River.

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Instantaneous AGN feedback at the central part of NGC 5728

  • Shin, Jaejin;Woo, Jong-Hak;Chung, Aeree;Baek, Junhyun;Cho, Kyuhyoun;Kang, Daeun;Bae, Hyun-Jin
    • The Bulletin of The Korean Astronomical Society
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    • v.44 no.1
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    • pp.36.2-36.2
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    • 2019
  • Using VLT/MUSE and ALMA data, we present a spatially-resolved analysis of the central part of NGC 5728. We find enhanced star formation (${\sim}1.8M{\odot}/yr/kpc2$) at a region where AGN gas outflows intersect the star formation ring. In contrast, significantly weaker CO emission (~3.5 times) is found at the same region compared to other regions in ring, suggesting positive AGN feedback on star formation. On the other hand, we detect gas outflows outside of the spiral arms, implying that the inflowing gas in the arms is removed (i.e., negative feedback). Even though the positive and negative feedback are expected at the central part of NGC 5728, the impact of the AGN feedback in galaxy scale may be insignificant.

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Debt Investment Outflows and Inflows in Korea and Covered Interest Parity Deviation (채권시장 자본유출입과 무위험 금리평형 이탈)

  • Gab-Je Jo
    • Korea Trade Review
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    • v.47 no.1
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    • pp.181-198
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    • 2022
  • This paper investigates the arbitrage effect by the covered interest parity (CIP) deviation, as well as other push or pull factor effect on capital inflows and ouflows in the Korean bond market, by utilizing OLS, TSLS, IRF and VDC in EC model. The sample period covers February 2002 to December 2020. It is found that, the swap basis reflecting the CIP deviations have the significant effects on both debt investment inflows and debt investment outflows. Also, it is found that, the Korean risk factors have decreasing effects on foreigner's investment in the Korean bonds, while the global risk factors have decreasing effects on Korean resident's investment in the foreign bonds.

Outflow properties of DIGIT embedded sources

  • Kang, Seonmi;Lee, Jeong-Eun;Choi, Minho;Evans II, Neal J.;Dunham, Michael M.
    • The Bulletin of The Korean Astronomical Society
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    • v.40 no.1
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    • pp.80.1-80.1
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    • 2015
  • We present a study of outflows on 24 embedded young stellar objects selected from the source list of the Dust, Ice, and Gas in Time (DIGIT) Herschel key program. To study the relation between the CO outflows observed in low-J transitions and the properties of protostars more consistently with a homogeneous data set, we mapped the CO outflows of the selected targets in the J = 1-0 and J = 2-1 lines with two Korean telescopes (SRAO and TRAO). We compare CO outflow force ($F_{CO}$) with the bolometric luminosity, ($L_{bol}$) bolometric temperature, and the FIR molecular line luminosities of CO, $H_2O$, OH, and [O I] detected by the Herschel-PACS observations. We find that $F_{CO}$ of J = 1-0 is greater than that of 2-1 by a factor of ~ 2. The well known correlation between $F_{CO\;2-1}$ and $L_{bol}$ is not very evident in our sample as a whole, but they show a rather strong correlation when IRAM 04191+1522 is excluded. IRAM 04191+1522 has relatively high $F_{CO\;2-1}$ in spite of its low $L_{bol}$. This object is a well-known VeLLO, which is believed in the quiescent phase of the episodic mass accretion in the embedded stage. $L_{bol}$ traces a current accretion, but $F_{CO\;2-1}$ traces accretion happened long ago. Therefore, the low-$L_{bol}$ with the high-$F_{CO\;2-1}$ can be explained by the episodic accretion. $F_{CO\;2-1}$ shows little correlation with individual FIR line luminosities of CO, $H_2O$, OH, while [O I] and total FIR line luminosity seem to have correlations with $F_{CO\;2-1}$. This result is interpreted as the accretion energy deposits on species differently depending on shock properties, but the total FIR line luminosity sums the total accretion energy dispersed to different species.

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[Fe II] 1.64 ${\mu}m$ images of Jets and Outflows from Young Stellar Objects in the Carina Nebula

  • Shinn, Jong-Ho;Pyo, Tae-Soo;Lee, Jae-Joon;Lee, Ho-Gyu;Koo, Bon-Chul;Sung, Hwan-Kyung;Moon, Dae-Sik;Kyeong, Jae-Mann;Park, Byeong-Gon
    • The Bulletin of The Korean Astronomical Society
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    • v.37 no.1
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    • pp.74.2-74.2
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    • 2012
  • We present [Fe II] 1.64 ${\mu}m$ imaging observations for jets and outflows from young stellar objects over the northern part (-24'${\times}$45') of the Carina Nebula, a typical evolved massive star forming region. The observations were performed with IRIS2 of Anglo-Autralian Telescope and the seeing was -1.5". Several jets and outflows features are detected at seven different regions, and one new Herbig-Haro Object is identified. The [Fe II] features have knotty and elongated shapes, and distribute around the triangular area formed by the star clusters Tr 14, Tr 15, and Tr 16, which contain many massive stars. The [Fe II] feature shows a highest detection rate (3.2 %) for the earliest stage YSOs, and the rate decreases as the stage evolves. The low detection rate (1.5 %) of [Fe II] features from the numerous YSOs seem to be related with the severe radiation environment of the Carina Nebula. The outflow rate shows reasonable relations with the physical parameters of the corresponding YSOs-derived from the SED fitting-such as the accretion luminosity, the stellar mass, the stellar age, the disk accretion rate, etc.

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POLARIZATION OF THOMSON SCATTERED LINE RADIATION FROM BROAD ABSORPTION LINE OUTFLOWS IN QUASARS

  • Baek, Kyoung-Min;Bang, Jeong-Hoon;Jeon, Yeon-Kyeong;Kang, Suna;Lee, Hee-Won
    • Journal of The Korean Astronomical Society
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    • v.40 no.1
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    • pp.1-7
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    • 2007
  • About 10 percent of quasars are known to exhibit deep broad absorption troughs blueward of prominent permitted emission lines, which are usually attributed to the existence of outflows slightly above he accretion disk around the supermassive black hole. Typical widths up to 0.2c of these absorption roughs indicate the velocity scales in which special relativistic effects may not be negligible. Under he assumption of the ubiquity of the broad absorption line region in quasars, the broad emission line flux will exhibit Thomson scattered components from these fast outflows. In this paper, we provide our Monte Carlo calculation of linear polarization of singly Thomson scattered line radiation with the careful considerations of special relativistic effects. The scattering region is approximated by a collection of rings that are moving outward with speeds ${\upsilon}=c{\beta}<0.2c$ near the equatorial plane, and the scattered line photons are collected according to its direction and wavelength in the observer's rest frame. We find that the significantly extended red tail appears in the scattered radiation. We also find that the linear degree of polarization of singly Thomson scattered line radiation is wavelength-dependent and hat there are significant differences in the linear degree of polarization from that computed from classical physics in the far red tail. We propose that the semi-forbidden broad emission line C III]1909 may be significantly contributed from Thomson scattering because this line has small resonance scattering optical depth in the broad absorption line region, which leads to distinct and significant polarized flux in this broad emission line.

1.64 ${\mu}m$ features of Jets and Outflows from Young Stellar Objects in the Carina Nebula

  • Shinn, Jong-Ho;Pyo, Tae-Soo;Lee, Jae-Joon;Lee, Ho-Gyu;Kim, Hyun-Jeong;Koo, Bon-Chul;Sung, Hwankyung;Chun, Moo-Young;Lyo, A. Ran;Moon, Dae-Sik;Kyeong, Jaemann;Park, Byeong-Gon;Hur, Hyeonoh;Lee, Yong-Hyun
    • The Bulletin of The Korean Astronomical Society
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    • v.39 no.1
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    • pp.56.2-56.2
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    • 2014
  • We present [Fe II] 1.64 ${\mu}m$ imaging observations for jets and outflows from young stellar objects over the northern part (${\sim}24^{\prime}{\times}45^{\prime}$) of the Carina Nebula, a massive star forming region. The observations were performed with IRIS2 of Anglo-Australian Telescope and the seeing was ~1.5". Eleven jets and outflows features are detected at eight different regions, and are termed as Ionized Fe Objects (IFOs). The [Fe II] features have knotty or elongated shapes, and the detection rate of IFOs against previously identified YSOs is 1.4%. Four IFOs show anti-correlated peak intensities in [Fe II] and $H{\alpha}$, where the ratio I([Fe II])/I($H{\alpha}$) is higher for longish IFOs than for knotty IFOs. We estimate the outflow mass loss rate from the [Fe II] flux using two different methods. The jet-driving objects are identified for three IFOs (IFO-2, -4, and -7). The ratios of the outflow mass loss rate over the disk accretion rate for IFO-4 and -7 are consistent with the previously reported values ($10^{-2}-10^{+1}$), while the ratio is higher for IFO-2. This excess may result from underestimating the disk accretion rate. Other YSO physical parameters show reasonable relations or trends.

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Analysis of Regional Income Outflows through Comparing GRDP and GRNI (지역내총생산과 지역총소득 비교를 통한 소득의 역외 유출 분석)

  • Jeong, Jae-joon
    • Journal of the Economic Geographical Society of Korea
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    • v.21 no.4
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    • pp.321-334
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    • 2018
  • There are many factors that cause uneven regional developments in the country and one of main factors is outflow of regional income or products. The purpose of this study is to analyze regional production runoff by comparing GRDP and GRNI in basic local governments level. In this study, GRNI of basic local governments are estimated by local income tax data, The results of the study are as follows. Firstly, GRNI is more concentrated than GRDP. The analysis of Moran I showed that the spatial autocor-relation of GRNI is more distinct than that of GRDP. Local Moran I analysis shows that spatial hot spots and cold spots are more apparent in GRNI than GRDP. Secondly, the outflows of GRDP into a small number of regions are apparent. In about 80% of basic local governments, the net outflows of GRDP occur. The large net outflow regions are cities where manufacturing industry has developed and in the 20 lowest net outflow rate regions, 70-80% of GRDP outflows. The large net inflow regions are metropolitan area in Seoul and large local cities. Seocho-gu, Yongsan-gu, and Gangnam-gu in Seoul have a large net inflows and net inflow rates are over 90% of GRDP.