• 제목/요약/키워드: "Black Korea"

검색결과 3,452건 처리시간 0.032초

AN AXISYMMETRIC, NONSTATIONARY BLACK HOLE MAGNETOSPHERE

  • PARK SEOK JAE
    • 천문학회지
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    • 제33권1호
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    • pp.19-28
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    • 2000
  • In the earlier papers we analyzed the axisymmetric, nonstationary electrodynamics of the central black hole and a surrounding thin accretion disk in an active galactic nucleus. In this paper we analyze the axisymmetric, nonstationary electrodynamics of the black hole magnetosphere in a similar way. In the earlier papers we employed the poloidal component of the plasma velocity which is confined only to the radial direction of the cylindrical coordinate system. In this paper we employ a more general poloidal velocity and get the Grad-Shafranov equation of the force-free magnetosphere of a Kerr black hole. The equation is consistent with the previous ones and is more general in many aspects as it should be. We also show in more general approaches that the angular velocity of the magnetic field lines anchored on the accreting matter tends to become close to that of the black hole at the equatorial zone of the hole.

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검정콩 청국장의 생리활성 및 발효중 Phytoestrogen 함량의 변화 (Biological Activities of Chungkugjang Prepared with Black Bean and Changes in Phytoestrogen Content during Fermentation)

  • 손미예;서권일;이상원;최성희;성낙주
    • 한국식품과학회지
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    • 제32권4호
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    • pp.936-941
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    • 2000
  • 검정콩을 이용하여 제조된 청국장의 기능적 특성을 평가하기 위하여 검정콩 청국장의 메탄올 추출물에 대한 몇가지 기초적인 생리활성과 발효중 phytoestrogen화합물(daidzein, genistein)의 함량변화를 조사하였다. 대두 청국장의 추출물은 대부분의 시험균주에 대하여 거의 항균활성이 없거나 약하게 나타났으나, 검정콩 청국장의 추출물은 시험균주 모두에서 항균활성을 나타내었다. 특히, 소립 검정콩의 청국장 추출물의 항균활성이 대립 검정콩보다 강하였다. 대립 및 소립 검정콩 청국장의 수소공여능은 각각 76.4및 75.5%로서 대두 청국장의 67.3%에 비하여 더 높게 나타났다. 또한 아질산염 소거능은 각 청국장 추출물에서 대조구에 비하여 모두 90%이상을 나타내었다. Linoleic acid에 대한 과산화물 및 흰쥐의 간 지질에 대한 TBA의 수치는 청국장의 추출물을 첨가한 시험구가 첨가하지 않은 대조구에 비하여 낮았으며, 그 항산화 효과는 소립 검정콩, 대립 검정콩 및 대두 청국장의 추출물 순이었다. Daidzein 및 genistein의 함량은 청국장 발효중 점진적으로 증가하였으며, 대두 청국장에 비하여 검정콩 청국장의 함량이 훨씬 높았고, 대립 검정콩이 소립 검정콩으로 제조한 청국장의 함량보다 높게 나타났다. 또한 genistein 함량은 대체로 daidzein 함량의 2배정도였다.

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진도산 검정쌀 전분의 분자구조적 특성 (Molecular Structural Properties of Chindo Black Rice Starch)

  • 박종훈;오금순;강길진;김관
    • Applied Biological Chemistry
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    • 제43권4호
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    • pp.241-246
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    • 2000
  • 진도산 검정쌀 전분의 분자 구조적 특성을 구명하고 신선찰벼와 비교 검토하였다. 진도산 검정쌀과 신선찰벼의 전분-요오드 복합체의 최대흡수파장은 각각 523 nm, 521 nm였고, 고유점도는 각각 183 ml/g, 178 ml/g였으며, ${\beta}-amylolysis$ limit(%)는 각각 62.8%, 60.3%였다. 진도산 검정쌀은 요오드 반응과 Sepharose CL-2B의 용출패턴 결과로 찹쌀임을 알 수 있었다. 진도산 검정쌀의 아밀로펙틴의 사슬 분포는 중합도 55이상(획분 I), 중합도 $40{\sim}50$(획분 II), 중합도 $15{\sim}20$(획분 III)으로 분포하였으며, 획분 II에 대한 획분 III의 비율(A/B 사슬비)는 진도산 검정쌀이 3.02, 신선찰벼가 2.82로 나타났다. 또한, 초장쇄 부분이 획분 I은 진도산 검정쌀이 신선찰벼의 아밀로펙틴 보다 많았다. 진도산 검정쌀의 아밀로펙틴 베타-한계 덱스트린 분자량 분포는 신선찰벼와 비슷하였다. 베타-한계 덱스트린의 사슬 분포는 중합도 55이상(획분 I), 중합도 $30{\sim}45$(획분 II), 중합도 $10{\sim}20$(획분 III)으로 분포하였으며, 진도산 검정쌀과 신선찰벼는 큰 차이가 없었다. 이러한 결과로부터 진도산 검정쌀 전분은 polymodal 구조를 갖는 아밀로펙틴으로 구성되어 있으며 신선찰벼와 구조적으로 유사하였다.

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시간에 따라 변하는 블랙흘 자기권의 'GRAD-SHAFRANOV 방정식' (THE NONSTATIONARY 'GRAD-SHAFRANOV EQUATIONS' IN THE BLACK HOLE MAGNETOSPHERES)

  • 박석재;이태형
    • 천문학논총
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    • 제18권1호
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    • pp.15-20
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    • 2003
  • In the earlier papers we analyzed the axisymmetric, nonstationary electrodynamics of the central black hole and a surrounding thin accretion disk in an active galactic nucleus. Based on those papers we analyze the axisymmetric, nonstationary black hole magnetosphere in this paper. We concentrate on deriving the ‘Grad-Shafranov equations’; both in the force-free and non-force-free cases. In the time-independent limit our equations naturally coincide with stationary equations as they should.

시간에 따라 변하는 블랙홀 자기권의 플라즈마 속도 (PLASMA VELOCITIES IN THE NONSTATIONARY BLACK HOLE MAGNETOSPHERE)

  • 박석재
    • 천문학논총
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    • 제17권1호
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    • pp.7-10
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    • 2002
  • In the earlier papers we analyzed the axisymmetric, nonstationary electrodynamics of the central black hole and a surrounding thin accretion disk in an active galactic nucleus. Based on those papers we analyze the axisymmetric, nonstationary force-free black hole magnetosphere and the motion of the plasma. We concentrate on deriving the relations between the velocity components of the plasma and those of the accreting magnetic field lines. We conclude that the former are given by the sum of the latter and the magnetic field terms.

PLASMA WAVE PROPAGATION IN THE BLACK HOLE IONOSPHERE

  • Park, Seok-Jae
    • 천문학회지
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    • 제28권2호
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    • pp.147-152
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    • 1995
  • An axisymmetric, stationary electrodynamic model of the central engine of an active galactic nucleus has been well formulated by Macdonald and Thorne. In this model the relativistic region around the central black hole must be filled by highly conducting plasma. We analyze plasma wave propagation in this region and discuss the results. We find that the ionosphere cannot exist right outside of the event horizon of the black hole. Another interesting aspect is that certain resonance phenomena can occur in this case.

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On the Geometry of Charged Rotating Black Holes

  • 윤종국
    • 한국수학사학회지
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    • 제35권2호
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    • pp.59-70
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    • 2022
  • In this paper, we review some aspects of geometry for charged rotating black holes which are formed from the gravitational collapse of a massive spinning star with electric charge. We also introduce the computation of entropy for black holes from loop quantum gravity which is a quantum theory of gravity based on Einstein's theory of general relativity.

Sexual Size Dimorphism and Morphological Sex Determination in the Black-billed Magpie in South Korea (Pica pica sericea)

  • Lee, Sang-Im;Jang, Hyun-Joo;Eo, Soo-Hyung;Choe, Jae-Chun
    • Journal of Ecology and Environment
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    • 제30권2호
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    • pp.195-199
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    • 2007
  • Statistical tools for determining sex in the sexually monomorphic black-billed magpie based on morphological characters have been developed based on studies of European and North American populations. However, since no morphological method has been developed for black-billed magpies in Korea, it has been difficult to conduct field studies that require information about the sex of individuals. We present two discriminant equations for determining sex of second-year (SY) and after-second-year (ASY) magpies in north- and midwestern part of South Korea. Based on morphological measurements on 105 SY (56 females, 49 males) and 72 ASY (36 females, 36 males) individuals, we found body mass, wing chord, and head length to be the most useful features for morphological sex determination. The accuracy of our method was 86.5% for SYs and 93.1% for ASYs, which is similar to values reported previously from American and European magpies. Since the equations contain morphological traits which are only minimally susceptible to seasonal variation and measurement errors, our discriminant equations should be both useful and robust for sex determination on black-billed magpies in the northern and mid-western regions of South Korea.

EDLC용 Carbon-PTFE 전극의 전기화학적 특성에 미치는 변수 연구 (Study of Parameters on the Electrochemical Properties of Carbon-PTFE Electrode for Electric Double Layer Capacitor)

  • 김익준;양선혜;전민제;문성인;김현수
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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    • pp.355-356
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    • 2006
  • This work describes the effect of the number of roll pressing and the composition of carbon black on the electric and mechanical properties of carbon-PTFE electrode, in which composition is MSP20 : carbon black: PTFE = 95-X : X : 5 wt.%. It was found that the best electric and mechanical properties were obtained for sheet electrode roll pressed about 15 times and for sheet electrode, in which composition is MSP20 carbon black : PTFE = 80 : 15 : 5 wt%. These behaviors could be explained by the network structure of PTFE fibrils and conducting paths linked with carbon blacks, respectively. On the other hand, cell capacitor using the sheet electrode with 15 wt.% of carbon black attached on aluminum current collector with the electric conductive adhesive, in composition is carbon black : CMC = 70 : 30 wt.%, has exhibited the best rate capability between 0.5 $mA/cm^2$ ~ 100 $mA/cm^2$ current density and the lowest ESR.

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