• Title/Summary/Keyword: BH

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Establishing New Black Hole Mass Estimators of Active Galactic Nuclei with Hydrogen Brackett Lines

  • Kim, Do-Hyeong;Im, Myeong-Sin
    • The Bulletin of The Korean Astronomical Society
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    • v.37 no.1
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    • pp.51.2-51.2
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    • 2012
  • Red Active Galactic Nuclei (AGNs) are suspected to intermediate stage between ULIRG and AGN phase. As well as, red AGNs are suspected to have more than 50% of whole AGN population. For understanding the characteristics of red AGN, Black Hole (BH) mass is a key property and can not be estimated by existed method such as reverberation mapping and single epoch method using 5100A continuum and Balmer lines. Thus we still don't know their characteristics and properties in clearly. To estimate properties of red AGNs without the effect of dust extinction, we obtained Near InfraRed (NIR) spectra of 31 reverberation mapped AGNs and 49 Palomar-Green(PG) Quasi-Stellar Objects (QSOs) by using the infrared camera (IRC) of AKARI space telescope with unique wavelength range 2.5-5.0 ${\mu}m$. Upon this spectra, we measured the FWHM and luminosity of Brackett ${\alpha}$ and ${\beta}$ lines for deriving new BH mass estimators of AGNs.

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Calculation of the Force Constants of Heteronuclear Diatomic Molecules by Use One Center Function. Ⅱ. Cubic Force Constants (일점전개함수에 의한 Heteronuclear Diatomic Molecules의 Force Constants의 계산 II. Cubic Force Constants)

  • Kim Hojing;Kim Hie-Joon
    • Journal of the Korean Chemical Society
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    • v.16 no.5
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    • pp.261-264
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    • 1972
  • The cubic force constants of the binary hydrides, LiH, BeH, BH, CH, NH and OH are evaluated by use of the one center function of Bishop et. al. The results are reasonably good. The master formula suggested in the previous report of the present author is found relatively insensitive to the crudities of the wave function.

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Diastereoselective Reduction of 2,3-Dioxo-4-carboxy-5-substituted Pyrrolidines Using NaBH4/AcOH and Heterogenous Hydrogenation Reactions

  • Mohammat, Mohd Fazli;Mansor, Nurul Shulehaf;Shaameri, Zurina;Hamzah, Ahmad Sazali
    • Journal of the Korean Chemical Society
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    • v.59 no.1
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    • pp.31-35
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    • 2015
  • Diastereoselective reduction of 2,3-dioxo-4-carboxy-5-(substituted)pyrrolidine 1 by $NaBH_4/AcOH$ and heterogenous hydrogenation were reported. Stereochemical assignment and diastereomeric ratios of the products were determined using $^1H$ NMR and single crystal X-ray analyses. The steric factors of the C-5 substituents of the pyrrolidinone was shown to have an interesting influence on both the yield and diastereoselectivity of the reduced product.

Synthesis of Naftifine-Related Allylamine as a Potential Antimycotics (항진균제 Naftifine 구조와 관련된 알릴아민류의 합성)

  • Kim, Wook;Park, Eun-Ju;Seo, Hee-Kyong;Shin, Boo-Ahn;Choi, Bo-Gil;Chung, Byung-Ho
    • YAKHAK HOEJI
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    • v.37 no.3
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    • pp.247-253
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    • 1993
  • Eight new derivatives of allylamine which are related to naftifine and expected to have antifungal activity were synthesized. Schiff base 2a-2d and 2'e-2'h were obtained by conventional methods using trans-cinnamylamine or trans-cinnamaldehyde. The reduction of azomethine linkage with NaBH$_{4}$ yielded secondary amine 3a-3h, which were then methylated by means of HCHO and excess NaBH$_{4}$ or HCOOH to give 4a-4h.

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Estimating Black Hole Mass in Active Galactic Nuclei with Hydrogen Brackett lines

  • Kim, Do-Hyeong;Im, Myeong-Sin
    • The Bulletin of The Korean Astronomical Society
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    • v.35 no.2
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    • pp.32.2-32.2
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    • 2010
  • Red dusty Active Galactic Nuclei (AGNs) are suspected to mid-stage between ULIRG and AGN phase. As well as, they are suspected that they have more than 50% of AGN population. To understand character of red AGN, Black Hole (BH) mass of red AGN is a key property and haven't measured by existing method such as reverberation mapping and single epoch method. So we still don't know their character and properties clearly. To estimate properties of red AGNs escape from effect of dust-obscuration, we have obtained Near InfraRed (NIR) spectra of 31 reverberation mapped AGNs and 49 Palomar-Green(PG) Quasi-Stellar Object (QSO) using the infrared camera (IRC) for AKARI with unique wavelength range 2.5-$5.0{\mu}m$. From this spectra, we measured the FWHM and luminosity of brackett ${\alpha}$, ${\beta}$ at 4.0, 2.6 micron meter for deriving new BH mass estimators based on the properties of Brackett line emission.

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bservational Evidence for the Coevolution between Supermassive Black Holes and Host Galaxies

  • Kim, Minjin
    • The Bulletin of The Korean Astronomical Society
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    • v.42 no.1
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    • pp.27.4-27.4
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    • 2017
  • (1) The correlation between the mass of supermassive black holes (SMBHs) and the properties of their host galaxies suggests that SMBHs and host galaxies are closely linked in their formation and evolution. While the exact origin of their relationship is still under debate, theoretical models often invoke feedback from active galactic nuclei as a crucial mechanism for establishing the BH-host correlation. In the first part of my talk, I will present possible observational biases in the BH-host relation, and methods to overcome these biases. I will also report our efforts to find observational sign of the AGN feedback in high-z young luminous AGNs. (2) While intermediate-mass black hole (IMBH) is thought be cosmologically important class to understand the link between stellar mass black holes and SMBHs, it is extremely rare in the present-day Universe. In the second part of this talk, I will report a Gemini/GMOS-N IFU study of an ultraluminous X-ray source in NGC 5252, which is a possible candidate of an off-nuclear non-stellar black hole.

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Heuristic Algorithm for the Single-machine Scheduling with Periodic Maintenance (주기정비를 고려한 단일기계 일정계획을 위한 휴리스틱 알고리즘 설계)

  • Lee, Sang-Heon;Lee, In-Gu
    • Journal of Korean Institute of Industrial Engineers
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    • v.34 no.3
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    • pp.318-327
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    • 2008
  • This paper considers a single-machine scheduling problem with availability constraints. In many realistic situations, machines may not be always available due to various reasons such as maintenance, breakdown and repair. However, most literature on scheduling assume that the machines are available at all times. This paper deals with a single-machine scheduling problem with periodic maintenance. If the maintenance decision is made jointly with the job scheduling, the system will be more effective. The objective is to minimize the total completion time of jobs. This problem is proved to be NP-hard in the strong sense. The proposed breaking heuristic(BH) algorithm rule is established by some theorems and conditions. Our computational results show that the BH algorithm is much more efficient than existing heuristic.

Calculation of the Polarizability for Simple Molecules by the Variation Method (변분법에 의한 간단한 분자의 편극율의 계산)

  • Sangwoon Ahn
    • Journal of the Korean Chemical Society
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    • v.22 no.2
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    • pp.62-66
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    • 1978
  • The polarizability tensor components for $NH_3,\;BH_3,\;HCN,\;C_2H_4,\;PO,\;PO^-$ and CO molecules are calculated by the variation method. The parallel components of the polarizability are closer to the experimental values than those of CNDO/2, MINDO/1 and MINDO/2, but the perpendicuar components of the polarizability are not closer to the experimental values than those of the other methods.

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Preliminary Identification of Branching-Heteroscedasticity for Tree-Indexed Autoregressive Processes

  • Hwang, S.Y.;Choi, M.S.
    • Communications for Statistical Applications and Methods
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    • v.18 no.6
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    • pp.809-816
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    • 2011
  • A tree-indexed autoregressive(AR) process is a time series defined on a tree which is generated by a branching process and/or a deterministic splitting mechanism. This short article is concerned with conditional heteroscedastic structure of the tree-indexed AR models. It has been usual in the literature to analyze conditional mean structure (rather than conditional variance) of tree-indexed AR models. This article pursues to identify quadratic conditional heteroscedasticity inherent in various tree-indexed AR models in a unified way, and thus providing some perspectives to the future works in this area. The identical conditional variance of sisters sharing the same mother will be referred to as the branching heteroscedasticity(BH, for short). A quasilikelihood but preliminary estimation of the quadratic BH is discussed and relevant limit distributions are derived.

Nanoconfinement effects of MCM-41 on the thermal decomposition of metal borohydrides

  • Kim, Sanghoon;Song, Hyejin;Kim, Chul
    • Analytical Science and Technology
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    • v.31 no.1
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    • pp.1-6
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    • 2018
  • We used differential scanning calorimetry and a thermogravimetric analysis to investigate the effect of being confined in mesoporous MCM-41 on the decomposition of lithium borohydride and magnesium borohydride when heated. The confinement did not cause a phase transition of the metal borohydrides inside MCM-41, but did lower their decomposition temperature. With the exception of a lowering of the temperature, the decomposition reaction mechanism of the metal borohydrides was nearly the same for both the bulk and confined samples.