• 제목/요약/키워드: large viewing angle

검색결과 64건 처리시간 0.03초

Observational Feature of Ejecta-Companion Interaction of A Type Ia SN 2021hpr Via The Very Early Light Curve

  • 임구;임명신;백승학;윤성철;최창수;김소피아;서진국;강원석;김태우;성현일;김용기;윤요라
    • 천문학회보
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    • 제46권2호
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    • pp.50.3-51
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    • 2021
  • The progenitor of Type Ia supernovae is largely expected as a close binary system of a carbon/oxygen white dwarf (WD) primary and its secondary non-degenerate (single degenerate; SD) or degenerate companion (double degenerate; DD). Here we present a high-cadence monitoring observation of SN 2021hpr in a spiral galaxy, NGC 3147. SN 2021hpr shows typical characteristics as a normal type Ia supernova from its photometric (Δm15(B)=1.01±0.03, dust free MB,max=-19.45±0.02) and spectroscopic data. To investigate its progenitor system, we fit the early part of BVRI-band light curve simultaneously with a combined version of ejecta-companion and simple power-law model. As a result, we found a significant feature of an early excess possibly from a 7.63±0.52R-sized companion at the optimal viewing angle while the fit is not successful at the common viewing angle. No possible red sources brighter than F555W=-7.01 AB mag is detected at the SN location in Hubble Space Telescope (HST) pre-explosion images, excluding massive stars with initial mass of >16M as companions. We suggest the progenitor system of SN 2021hpr can be a fairly large companion such as a main sequence, a low mass subgiant, and a helium giant star. In addition, a possibility of the ejecta-Disk Originated Matter (DOM) interaction for the DD scenario considering linearly-rising early flux still remains.

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Reduction of Gamma Distortion in Oblique Viewing Directions in Polymer-stabilized Vertical Alignment Liquid Crystal Mode

  • Kim, Hyo Joong;Lim, Young Jin;Murali, G.;Kim, Min Su;Kim, Gi Heon;Kim, Yong Hae;Lee, Gi-Dong;Lee, Seung Hee
    • Current Optics and Photonics
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    • 제1권2호
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    • pp.157-162
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    • 2017
  • In large liquid crystal displays, the image quality in an oblique viewing direction is a crucial issue. From this perspective, 8-domain polymer-stabilized vertical alignment (PS-VA) mode has been developed to suppress the color shift in oblique viewing directions, compared to that in 4-domain PS-VA mode. To realize the 8-domain PS-VA, the four domains in a pixel are each divided into two regions, such that applying different electric potentials result in different tilt angles in these two regions, while keeping four azimuthal directions in each domain. However, applying different voltages in a pixel causes drawbacks, such as requiring additional processes to construct a capacitor and a transistor, which will further reduce the aperture ratio. Here we propose a different approach to form the 8-domain, by controlling surface polar anchoring energy and the width of patterned electrodes in two regions of a pixel. As a result, the gamma-distortion index (GDI), measured at an azimuthal angle of $0^{\circ}$, is reduced by about 23% and 8%, compared to that of a conventional 4-domain at polar angles of $30^{\circ}$ and $60^{\circ}$ respectively.

TFT-LCD 3차원 시뮬레이션에서의 광 경로에 대한 고려 (Study for the Real Optical Path in the TFT-LCD 3-dimensional Simulation)

  • 최경욱;김기범;박우상
    • 한국전기전자재료학회논문지
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    • 제19권2호
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    • pp.195-199
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    • 2006
  • We report a novel simulation method to calculate optical transmission considering the real paths of optic introduced in a unit pixel of TFT-LCDs using three-dimensional molecular director simulation of the tensor model. The simulation of optical path transmission profile was carried out by calculating new permittivity considered the real paths of optic in liquid crystal cell. As a result, it was clarified that the electro-optic characteristics such as movement of disclination line, contrast ratio and transmittance profile show a large difference according to the viewing angle compared with the conventional method.

15" XGA Dual-plate OLED Display (DOD) based on Amorphous Silicon (a-Si) TFT Backplane

  • Han, Chang-Wook;Kim, Woo-Chan;Kim, Seung-Tae;Tak, Yoon-Heung;Ahn, Byung-Chul;Kang, In-Byeong;Chung, In-Jae
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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    • pp.123-126
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    • 2008
  • We report the improved AMOLED with a-Si TFT backplane based on our unique structure. Our new structure is called Dual-plate OLED Display (DOD). It can also achieve not only higher uniformity of luminance in large-sized display due to low electrical resistance of common electrode but also wider viewing angle.

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원거리 홍채 인식에서 효율적 조명 조사방법에 관한 연구 (Research on the efficient illumination method in iris recognition at a distance)

  • 조현수;배광혁;박강령;김재희
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2008년도 하계종합학술대회
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    • pp.969-970
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    • 2008
  • This paper proposes illumination-efficient iris image capturing method. face capture method for extraction of iris pattern with one high resolution camera needs a large scale near infrared illumination. we replace high-resolution camera with co-optic-axial combination between wide view camera and narrow view camera. because this method needs small scale illumination that illuminate only narrow camera viewing angle, we can capture iris pattern image with small scale near infrared illumination.

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반사형 Optically Compensated Splay 셀의 전기-광학 특성 (Electro-optic Characteristics of Reflective Optically Compensated Splay Cell)

  • 송제훈;오상민;이종문;이승희
    • 한국전기전자재료학회논문지
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    • 제17권9호
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    • pp.983-987
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    • 2004
  • We have studied electro-optic characteristics of reflective optically compensated splay (R-OCS) cell. The initial configuration of this cell is in splay form such that a mid director lies parallel to the substrate and around it hybrid structure is formed symmetrically so the optically compensation effect exists. Optimized optical configurations could be achieved by using a single polarizer, a quarter-wave film and a cell with quarter-wane retardation. The optimal cell retardation is 0.34 ${\mu}$m, allowing to have large cell gap. The cell provides high contrast ratio of 80:1 at normal direction and the region with contrast ratio over 5:1 covert up to 160$^{\circ}$ horizontally and vertically at all wavelength range.

Detection of a Large Amount of Diffuse Extraplanar Dust in NGC 891

  • 선광일
    • 천문학회보
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    • 제36권2호
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    • pp.71.1-71.1
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    • 2011
  • Significant discrepancies have been found between the dust masses of edge-on spiral galaxies derived from various tracers (optical/near-infrared, far-infrared/sub-millimeter observations, and the variation of dust attenuation with viewing angle). Here we report the first detection of a vertically extended far-ultraviolet (FUV) and near-UV (NUV) emission in an edge-on spiral galaxy NGC 891. The vertically extended emission is interpreted as the dust-scattered light due to a extraplanar dust layer in NGC 891 that contains about the same mass as the standard thin dust disk. This new dust component completely encloses the stellar disk and bulge, and solves the puzzle of dust mass.

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새로운 유지전극 구조에 의한 ac-PDP 에서의 효율 개선에 관한 연구 (A study on the Improvement of the luminous efficiency with new sustaining electrode structurs in ac-PDPs)

  • 이재영;신중흥;박정후;조정수
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2000년도 하계학술대회 논문집 C
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    • pp.1818-1820
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    • 2000
  • Due to recent technology advances, needs for flat panel displays, plasma display panels(PDPs) whose advantages are simple structure, high resolution, wide viewing angle is increasingly expected to be the first flat panel of large screen, walt hanging TVs. But the luminance and luminous efficiency of color PDP is net up to the level of a CRT. So, New electrode shape which is different from the conventional electrode has to propose to improve the luminance and luminous efficiency. In this paper, we suggested new shaped electrodes. In new shaped electrode, the discharge current was reduced compared with conventional type by reducing the unnecessary diffusion loss near the barrier rib. However, the luminance was nearly the same as conventional type. So, the luminous efficiency improved about 35%.

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Low Cost Driving System for Plasma Display Panels by Eliminating Path Switches and Merging Power Switches

  • Lee, Dong-Myung;Hyun, Dong-Seok
    • Journal of Power Electronics
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    • 제7권4호
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    • pp.278-285
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    • 2007
  • Recently, plasma display panels (PDP) have become the most promising candidate in the market for large screen size flat panel displays. PDPs have many merits such as a fast display response time and wide viewing angle. However, there are still concerns about high cost because they require complex driving circuits composed of high power switching devices to generate various voltage waveforms for three operational modes of reset, scan, and sustain. Conventional PDP driving circuits use path switches for voltage separation and a scan switch to offer a scan voltage for reset and scan operations, respectively. In addition, there exist reset switches to initialize PDPs by regulating the wall charge conditions with ramp shaped pulses, which means the necessity of specific power devices for the reset operation. Because power for the plasma discharge accompanied by a large current is transferred to a panel via path switches, high power rating switches are used for path switches. Therefore, this paper proposes a novel low-cost PDP driving scheme achieved by not only eliminating path switches but also merging the function of reset switches into other switches used for sustain or scan operations. The simulated voltage waveforms of the proposed topology and experimental results implemented in a 42-inch panel to demonstrate the validity of using a new gate driver that merges the functions of power switches are presented.

대 면적 LCD에서 Patterned Spacer Color Filter 사용 시 발생하는 중력무라 분석 (The Analysis of Gravity Mura Induced in Patterned Spacer Color Filter on Large Size LCD)

  • 최석;정연학;김미숙;김귀현;김향율;김서윤;임영진
    • 한국전기전자재료학회논문지
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    • 제17권8호
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    • pp.871-874
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    • 2004
  • In recent, it is said that the trend of LCD is direction to pursue high qualities like as high transmittance, high contrast ratio, wide viewing angle, fast response time, and so on. Especially, it is known that these qualities are essential to large size LCD like as LCD TV and we can realize them through to uniform cell gap and deep black state. Until now, the ball spacer has been used to control of uniform cell gap. However, the existence of ball spacer inside the cell causes the deformation of the liquid crystal molecules and damage to alignment layer. Such a deformation of the liquid crystal causes light-leakage in the dark state, which lowers contrast ratio of the display. Nowadays, this problem has been solved by using Patterned Spacer on Color Filter. but Side Effect just as gravity mura has been induced. In this paper, we studied the mechanism on gravity mura in case of using patterned spacer on color filter.