• 펄프종이기술
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• 제43권1호
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• pp.11-16
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• 2011

This study was carried out in order to elucidate the effect of latex dosage and properties on aging behavior of coated paper. The coated paper with five different coating formulations were prepared and also four different latices were used. The coated paper were thermally aged at $105^{\circ}C$ for 14 days and the optical properties were measured. Increasing latex content increased the magnitude of reduction in brightness and whiteness. In addition, the variations in CIE a$^*b^*$ were larger with increasing latex dosage. Latex which has the lower gel content and the higher Tg showed the higher reduction in brightness and whiteness and much variation in CIE a$^*b^*$. However the particle size of latex didn't affect to thermal behavior of coated paper. These results indicate that latex which has higher Tg and lower gel content is the one of the main factors affecting aging behavior of coated paper.

• 천문학회보
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• 제44권1호
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• pp.67.1-67.1
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• 2019

We present 2-dimensional continuum radiative transfer modeling for EC53. EC 53 is a Class I YSO, which was brightened at $850{\mu}m$ by a factor of 1.5. This luminosity variation was revealed by the JCMT Transient Survey. The increase in brightness is likely related to the enhanced accretion. We aim to investigate how much increase of protostellar luminosity causes the observed brightness increase at $850{\mu}m$. Thus we modeled the SED of EC 53 both in the quiescence and (small scale) outburst phases, with and without the external heating from the interstellar radiation field (ISRF). We found that the internal protostellar luminosity should increase more to fit the observed flux enhancement if the ISRF is considered in the model.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 가을학술발표대회논문집
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• pp.25-26
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• 2023

The internal core material and external color of a sandwich panel have a significant impact on the performance of the sandwich panel. For use on roofs and walls, the internal core material and external color must be considered. Therefore, the surface and back side temperatures were measured for each exterior color and inner core material type. For the internal core materials, urethane foam and Expanded Poly Styrene(EPS), which are core materials mainly used in sandwich panels, were selected. As colors, black and ivory were selected according to brightness, and a total of five colors were selected: red, blue, and green, which are the three primary colors of light. As a result, there were differences in surface and temperature depending on the external color and type of internal core material. Regardless of the color, the temperature was measured lower for panels with urethane foam than for panels with an internal core of EPS. This is believed to have been influenced by the difference in thermal conductivity of urethane foam being 0.023W/(m·K) and that of EPS being 0.032W/(m·K). In addition, panels with a black exterior color were found to have higher surface and back temperatures than panels of other colors, and ivory-colored panels had lower back temperatures regardless of the core material. This is proportional to the brightness and light-absorbing characteristics.

• 한국정보통신학회논문지
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• 제18권9호
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• pp.2280-2288
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• 2014

기존의 고출력 LED의 디밍(Dimming) 제어 방법에는 펄스폭변조, 주파수변조, 아날로그 제어 방법이 있으며, 아날로그 디밍은 순방향 고출력 LED 전류를 조정하는 방법으로 0%~100%의 전 범위에서 선형 밝기 조절이 가능하나 순방향 전류를 변화시킴으로써 파장의 변화가 존재하고, 펄스폭변조 디밍 제어는 고출력 LED에 흐르는 정격 전류의 듀티를 가변하여 조도를 제어하는 방식으로 저 레벨(0%~10%)에서 선형 밝기 조정이 어렵다. 그리고 주파수변조 디밍 또한 저 레벨의 디밍에서 빛이 깜박거리는 문제를 내포하고 있다. 본 논문은 이러한 디밍 방식의 단점을 보완하고자 저 레벨 디밍 제어 시 아날로그 방식을 적용하고, 10%~100%의 디밍 제어 시에 펄스폭변조 방식을 적용하는 효율적인 디밍 제어 회로의 설계 및 구현을 제안한다. 전 범위에 걸쳐 선형 밝기 조절이 가능하고, 다양한 디밍 레벨에서 일정한 파장의 출력이 가능한 디밍 제어 회로를 구현하였으며, 실험 결과는 제안한 방법의 우수성을 보여주고 있다.

• 천문학회지
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• 제26권2호
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• pp.115-134
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• 1993

The light curve and radial velocity curve of multiperiodic dwarf cepheid VI719 Cyg (HD200925) with peculiar light curve have been reanalyzed in order to identify the oscillation modes to confirm the helium settling within the envelope. To do these, through the period search for the photometric and radial velocity data from the literature, two different periods were determined and the oscillation modes corresponding to the first and second periods were identified as the fundamental and first radial overtones. Hence the helium settling within the envelope was confirmed from the period ratio. The color excess, metallicity, effective temperature, and surface gravity corresponding to two different modes were determined and it was found that these parameters almost do not depend upon different oscillation mode. By utilizing the surface brightness method, we investigated the variation of angular diameter and radial displacement and it was found that the angular variation is very peculiar. Also by referring to the stellar models, mass and age were determined as $2.7M_{\bigodot}$ and 0.42 Gyr respectively which make this variable star heavier and younger than other multimode dwarf cepheids. Preliminary spectroscopic CCD observations were carried out and it was found that Mg in VI719 Cygni is nearly solar abundent according to the analysis of $5172.68{\AA}MgI$ line which is inconsistent with the photometric result. It was suggested that VI719 Cyg may be classified as a $\rho$ Pup stars according to the photometric characteristics.

• Journal of Astronomy and Space Sciences
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• 제14권1호
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• pp.59-66
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• 1997

V711 Tau의 채층활동을 조사하기 위하여 자외선 영역의 Mg II 방출선의 세기와 광도 변화의 상관 관계를 유추하였다. 첫째, 가시광선 영역의 광도곡선의 형태와 자외선 영역의 광도곡선의 형태를 비교하고, 둘째, IUE 고분산 스펙트럼에서 Mg II 방출선의 세기를 위상별로 측정하고 방출선 부근의 연속선을 이용하여 자외선 광도곡선을 완성하였다. 방출선의 세기와 광도곡선을 비교한 결과 방출선이 강하게 나타나는 위상, $0.^{p}4$에서는 광도가 어둡게 나타나 최소가 되고, 방출선의 세기가 약할 때는 광도가 밝아져서 최대가 되었다. 이는 자기장이 강한 위상에서는 채층활동과 흑점의 크기가 증가하고 반대로 자기장이 약한 위상에서는 채층활동과 흑점의 크기가 작다는 것을 뜻한다. 그러므로 자기장, 채층활동, 별 표면의 흑점과의 상관 관계가 밝혀지고, V711 Tau의 변광은 표면의 채층활동과 흑점에 의한 것이다.

• IEIE Transactions on Smart Processing and Computing
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• 제6권3호
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• pp.168-174
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• 2017

Videos recorded on surveillance cameras or by car black boxes at night have distorted images due to illumination variation. Therefore, it is difficult to analyze morphological characteristics of objects, and it is limiting to use such distorted images as evidence in traffic accidents. Image restoration is performed by amplifying the brightness of nighttime images using linearized gamma correction to increase their contrast (which destroys visual information) and by minimizing degradation factors caused by irregular traveling.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2008년도 한국우주과학회보 제17권2호
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• pp.24.4-25
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• 2008

Limb scanning measurements of the O2 (0-0) Atmospheric band emission by the TIDI instrument aboard the TIMED satellite during 2003-2005 are analyzed to examine the tidal effects on their vertical emission rate according to the solar and geomagnetic activities. The data are restricted at latitudes $60^{\circ}S-60^{\circ}N$ to avoid the contributions by the auroral emission. The variation of the vertical emission rate in latitude and local time is summarized in the yaw periods. The vertical emission profiles of the O2 (0-0) Atmospheric band nightglow averaged in the $10^{\circ}$ latitude range are investigated. The result shows the inverse relationship between the peak emission height and the integrated brightness.

• 한국인쇄학회지
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• 제26권1호
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• pp.17-28
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• 2008

The wood-pulp is treated with the three enzymes; Endo-xylanase, exo-xylanase and acetyl-esterase. The maximum value of relative activity appeared 0.95 in acetyl-esterase at $40^{\circ}C$, 0.9 in exo-xylanase at $40^{\circ}C$, and 0.8 in endo-xylanase at $50^{\circ}C$, respectively. And it has measured 0.8 in endo-xylanase, 0.95 in acetyl-esterase at pH 6 and 0.9 in exo-xylanase at pH 5, while the maximum value of relative activity does not rely on reaction time for three enzymes treatment, and the value was about 0.9, respectively. We have watched that decreased Kappa number and increased brightness. And it turned out that the three enzyme produced a lot of reducing sugar with wood-pulp treatment.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.1120-1123
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• 2008

Efficient, color stable multi-EML WOLED have been fabricated using newly synthesized yellowish green dopant Ir(chpy)3 or Ir(mchpy)3. The devices have high external quantum efficiency of 11.7%, color rendering index of 87, variation of CIE coordinate of (0.02, 0.01) between 10 to 5000 cd/m2, and low roll-off in efficiency with increasing brightness.