• 제목/요약/키워드: Angular Dependence

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Angular Dependence of Ferromagnetic Resonance Linewidth in Exchange Coupled CoFe/MnIr Bilayers (교환 결합력을 갖는 CoFe/MnIr 박막에서 강자성 공명 선폭의 각도 의존성 연구)

  • Yoon, Seok Soo;Kim, Dong Young
    • Journal of the Korean Magnetics Society
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    • v.26 no.2
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    • pp.50-54
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    • 2016
  • We analyzed the angular dependence of ferromagnetic resonance linewidth in exchange coupled CoFe/MnIr bilayers. The maximum and minimum linewidth was observed in the easy and hard direction of unidirectional anisotropy by exchange coupling, respectively, and it was well agreed with the angular dependence of exchange bias field. The maximum linewidth was due to the twist of CoFe magnetization near CoFe/MnIr interface from direction of pinned MnIr spin to direction of applied magnetic field. While, minimum linewidth more higher than that of CoFe was related to rotatable anisotropy field, and explained by easy axis distribution of MnIr grains.

The Light Sensitivity and Angular Dependence of the $Mg_2SiO_4$:Tb(MSO-S) TLD ($Mg_2SiO_4$:Tb(MSO-S) TLD의 광감수성과 방향의존성)

  • Kim, Do-Sung;Park, Myeong-Hwan
    • Journal of Radiation Protection and Research
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    • v.23 no.1
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    • pp.59-63
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    • 1998
  • The light sensitivity and angular dependence of the $Mg_2SiO_4$:Tb(MSO-5) TLD which affect the accuracy of the radiation dose measurement are investigated. Light-induced thermoluminescence of MSO-S TLD under the 200 lux fluorescent and the incandescent lamp for 8 hours are corresponding to 11 and 3 mR exposure, respectively. TL intensity ratio of the incident angle of ${\pm}80^{\circ}$ to normal incidence for MSO-S and badge type MSO-L are about 0.8 and 0.15, respectively.

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ERotating Bondi Accretion Flow with and without outflow

  • Han, Du-Hwan;Park, Myeong-Gu
    • The Bulletin of The Korean Astronomical Society
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    • v.45 no.1
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    • pp.52.4-53
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    • 2020
  • It is less well known that the properties, especially the mass accretion rate, of accretion flow are affected by the angular momentum of accreting gas. Park (2009) found that the mass accretion rate \dot{m}, mass accretion rate in units of Bondi accretion rate, is inversely proportional to the angular momentum of gas λ, at the Bondi radius where gas sound speed is equal to the free-fall velocity and proportional to the viscosity parameter α, and also Narayan & Fabian (2011) found a similar relation, but the dependence of the mass accretion rate of the gas angular momentum is much weaker. In this work, we investigate the global solutions for the rotating Bondi flow, i.e., polytropic flow accreting via viscosity, for various accretion parameters and the dependence of the mass accretion rate on the physical characteristics of gas. We set the outer boundary at various radius r_{out}=10^3~10^5 r_{Sch}, where r_{Sch} is the Schwarzschild radius of the black hole. For a small Bondi radius, the mass accretion rate changes steeply, as the angular momentum changes, and for a large Bondi radius, the mass accretion rate changes gradually. When the accreting gas has a near or super Keplerian rotation, we confirm that the relation between the mass accretion rate and angular momentum is roughly independent of Bondi radius as shown in Park (2009). We find that \dot{m} is determined by the gas angular momentum at the Bondi radius in units of r_{Sch}c. We also investigate the solution for the rotating Bondi flow with the outflow. The outflow affects the determination of the mass accretion rate at the outer boundary. We find that the relation between the mass accretion and the gas angular momentum becomes shallower as the outflow strengthens.

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Dependence of the peak fluxes of solar energetic particles on CME parameters and magnetic connectivity

  • Park, Jinhye;Moon, Yong-Jae;Lee, Harim;Kahler, S.W.
    • The Bulletin of The Korean Astronomical Society
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    • v.42 no.2
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    • pp.82.3-83
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    • 2017
  • We investigate the relationships between the peak fluxes of 18 solar energetic particle (SEP) events and associated coronal mass ejection (CME) 3D parameters (speed, angular width, and separation angle) obtained from SOHO, STEREO-A and/or B for the period from 2010 August to 2013 June. We apply the STEREO CME Analysis Tool (StereoCAT) to the SEP-associated CMEs to obtain 3D speeds and 3D angular widths. The separation angles are determined as the longitudinal angle between flaring regions and magnetic footpoints of the spacecraft, which are calculated by the assumption of Parker spiral field. The main results are as follows. 1) We find that the dependence of the SEP peak fluxes on CME 3D speed from multi-spacecraft is similar to that on 2D CME speed. 2) There is a positive correlation between SEP peak flux and 3D angular width from multi-spacecraft, which is much more evident than the relationship between SEP peak flux and 2D angular width. 3) There is a noticeable anti-correlation (r=-0.62) between SEP peak flux and separation angle. 4) The multiple regression method between SEP peak fluxes and CME parameters shows that the longitudinal separation angle is the most important parameter, and the CME 3D speed is secondary on SEP peak flux.

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Spectrophotometric Analysis of Behavior to Tyrosine Residue in the Yellow Fluorescent Cocoon of Bombyx mori (황색 형광견 중 Tyrosine잔기 거동의 분광학적 분석)

  • Yeo, Ju-Hong;Lee, In-Jeon
    • Journal of Sericultural and Entomological Science
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    • v.39 no.2
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    • pp.169-173
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    • 1997
  • The behavior of tyrosine(Tyr.) residue of Bombyx mori silk fiber from yellow fluorescent cocoon has been examined for the dependence of pH in aqueous silk solution under the presence of orange II salt. Through the peak separation of angular dependence of spectral pattern of 15N-Tyr. and [1-13C]-Tyr. between the fiber axis and the molecular bond direction, N-H bond in fiber as well as the orientation distribution around the fiber axis were analyzed. Also, and sericin component was obtained from these angular dependence of oriented spectral pattern. The pH dependence of the 13C NMR chemical shift of B. mori silk fibroin was examined in aqueous solution in the presince of orange II are broad at pH$\geq$7.0. However, these become sharper at pH$\geq$8.0 and remain sharp at higher pH. In these higher pH range, a chemical shift change occurs due to the deprotonation of the Tyr. side group of fibroin. At higher pH. such a hydrophobic cluster is destroyed because of the electrostatic interaction according to the deprotonation of the Tyr-OH group.

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Thickness Dependence of Ferromagnetic Resonance Properties in NiFe Thin Films (NiFe 박막의 두께에 따른 강자성 공명 특성 분석)

  • Kim, Dong Young;Yoon, Seok Soo
    • Journal of the Korean Magnetics Society
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    • v.23 no.2
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    • pp.37-42
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    • 2013
  • The out-of-plane and in-plane angular dependence of ferromagnetic resonance field was measured in NiFe thin films fabricated by magnetron sputtering. The effective magnetization was obtained from the out-of-plane angular dependence of ferromagnetic resonance field, which was well agreed with calculated one. The decrease of effective magnetization with NiFe thickness was due to the surface anisotropy constant of $K_s=-0.23\;erg/cm^2$. The in-plane uniaxial anisotropy fields were obtained from the in-plane angular dependence of ferromagnetic resonance field. The easy axis of in-plane uniaxial anisotropy field was rotated to the reverse direction of applied magnetic field during sample fabrication, which was explained by the antiferromagnetic NiFeO layer at sample surface.

Angular dependence of critical current of SmBCO coated conductor fabricated by co-evaporation method

  • Kim, Ho-Sup;Ha, Hong-Soo;Oh, Sang-Soo;Song, Kyu-Jeong;Ko, Rock-Kil;Ha, Dong-Woo;Kim, Tae-Hyung;Youm, Do-Jun;Lee, Nam-Jin;Moon, Seung-Hyun;Yoo, Sang-Im;Park, Chan
    • Progress in Superconductivity and Cryogenics
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    • v.10 no.2
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    • pp.16-19
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    • 2008
  • Angular dependence of critical current density of SmBCO coated conductor fabricated by co-evaporation method was investigated. For comparison, three samples were fabricated by a co-evaporation method and one sample was fabricated by a pulsed laser deposition process. The deposition system, named EDDC (Evaporation using Drum in Dual Chambers), is a batch type co-evaporation system, which is composed of reaction chamber and evaporation chamber. The normalized critical current density ratio ($I_c/I_c$(H//ab-plane)) of EDDC-SmBCO samples was found to be higher than that of PLD-YBCO sample in the whole range of angle. While the EDDC-SmBCO samples evidently had a peak at the angle of H//c-axis in the plot of the angular dependence of critical current, the normalized critical current of PLD-YBCO sample decreased monotonically without any peak as angle increased. The field dependence of critical current under the magnetic field parallel to the normal direction of those samples showed similar aspect in the range of $0\;G{\sim}5000\;G$.

Characteristics of the Angular-dependent Exchange Coupling Bias in Multilayer [Pt/Co]N-IrMn with Toward-in Plane Applied Fields (박막수직방향에서 면방향으로 회전하는 인가자기장에 대한 다층박막 [Pt/Co]N-IrMn의 교환바이어스의 각도의존특성)

  • Kim, S.S.;Yim, H.I.;Rhee, J.R.;Lee, S.S.;Hwang, D.G.
    • Journal of the Korean Magnetics Society
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    • v.18 no.4
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    • pp.142-146
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    • 2008
  • The angular dependence of the exchange bias($H_{ex}$) and coercivity($H_c$) in multilayer $[Pt/Co]_N-IrMn$ with applied measuring field rotated toward in-plane at angle $\theta$ from perpendicular-to-plane, has been measured. Multilayer films consisting of $Si/SiO_2/Ta(50)/Pt(4)/[Pt(15)/Co(t_{Co})]_N/IrMn(50)/Ta(50)(in\;{\AA})$ were prepared by magnetron sputtering under typical base pressure below $2{\times}10^{-8}$ Torr at room temperature. Magnetization measurements were performed on a vibrating sample magnetometer and extraordinary Hall voltage measurement systems after cooling from 550 K under a field of 2 kOe applied along the perpendicular to film direction. The hysteresis loop shifts from the origin not only along the field axis but also along the magnetization axis. $H_{ex}$ and $H_c$ show a $1/cos{\theta}$ and $1/|cos{\theta}|$ dependence on the angle($\theta$) between the applied measuring field and the perpendicular-film direction, respectively. This $1/cos{\theta}$ dependence can be accounted for by considering the angular dependence of strong out-of-plane magnetic anisotropy introduced during the field cooling.

Visual Perception for TCO'03 Angular-Dependence Luminance Uniformity of TFT-LCDs

  • Hsu, Yu-Ju;Chen, Hsin-Ming;Cheng, Yung-Chiang
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.671-674
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    • 2006
  • Due to the stricter requests of the human perception of images, many industrial standards such as TCO'03 have been made to survey the Flat Panel Displays (FPD) nowadays. The angular-dependence luminance uniformity is an important item to evaluate the performance of FPD. In this article, we focus on the above test item base on TCO'03 standard in the case of vertical direction of ${\pm}15^{\circ}$. With controlling the driving voltage toward the liquid crystals of TN-type TFT-LCD, there exists a voltage-driving range which can achieve the value of the $L_{max}/L_{min}$ at ${\pm}15^{\circ}\;{\leq}1.7$ readily. Both experiment and simulation have been well analysis.

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Wide-Angle Radar Target Classification with Subclass Concept (Subclass 개념을 이용한 넓은 관측각에서의 레이더 표적인식 성능향상에 관한 연구)

  • 서동규;김경태;김효태
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.13 no.8
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    • pp.777-782
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    • 2002
  • The range profile is easily obtainable and promising feature vector in the aspect of real-time radar target recognition system. However, the range profile is highly dependent on a aspect angle of a target and this dependence make it difficult the recognition over wide-angular region. In this paper, we propose the classifier with subclass concept in order to solve this dependence problem. Recognition results using six aircraft models measured at compact range facility are presented to show the effectiveness of this proposed classifier over wide-angular region.