• 조명전기설비학회논문지
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• 제26권10호
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• pp.9-15
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• 2012

There have been light pollution standards just for architectural lighting and sign in the "Light Pollution Abatement Law" so far. However, both of them regulate only one of the three main light pollution elements-"Glare". Therefore, it is imperative to do research on the other two light pollution elements-"Upward" and "Light Trespass" and make proper restriction. Subsequently, this study focuses on the upward light from the street light and suggests its analysis method. Eventually, this study aims to make viable management which is suitable for the nation and, in addition, to suggest appropriate level of restriction to "Light Pollution Abatement Law" by doing site survey.

• 한국환경과학회지
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• 제20권12호
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• pp.1599-1605
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• 2011

To evaluate heat environment surrounding plants diurnal change of leaf temperature in the broad-leaved deciduous and evergreen trees was measured with microclimatic environmental factors including global solar radiation, and upward and downward long wave radiation. Maximum daily solar radiation was 961.2 and 976.3 w/$m^2$ in August 9 and 23, respectively. Upward long wave radiation was slightly higher than downward long wave radiation, showing 404.2 w/$m^2$ in August 9 and 394.5 w/$m^2$ in August 23. In addition, daily maximum vapor pressure deficit was 5.42 and 6.84 kPa in August 9 and 23, respectively, indicating high evaporative demand. Quercus glauca and Acer mono was differently responded to changing light regimes. On August 9, leaf temperature at the top-positioned leaves of Acer plants was higher than air temperature as well as those of Quercus plants in the morning. This indicates that stomata in Acer plants were closed by heat stress or water stress in the morning, while Quercus plant maintained active transpiration by opening stomata. These results indicated that improved light regimes such as gap opening in the closed forest may not always affect positively in the physiology of understory plants.

• 조명전기설비학회논문지
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• 제25권12호
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• pp.21-26
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• 2011

This is a study to establish regulations against light pollution for lighting on roads. Many kinds of light pollution by luminaire on roads was calculated and analyzed by applying the classification method of luminaires(Cut-off classification of IDA-IESNA, BUG Rating Classification) and the calculation method of Upward Lighting Ratio of CIE among measures to prevent light pollution that international lighting organizations suggest. As a result of the analysis, it was found that the regulation by Cutoff of IESNA and ULR classification of CIE could be one for scattered light of light pollution compared to BUG classification but is not sufficient for the regulation of light tresspass or glare. BUG classification by each lighting zone was suggested as threshold value of the light pollution regulation considering domestic conditions.

• 천문학회보
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• 제45권1호
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• pp.44.1-44.1
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• 2020

Hα jets of cool chromospheric plasma are protruding into the solar corona 10-100 Mm above the photosphere. The driving mechanisms of Hα jets have been widely studied for decades. However, the detailed process is still elusive. We observed shock signatures moving along a dark jet using 1.6 meter Goode Solar Telescope at Big Bear Solar Observatory. The first shock front of the jet shows sharp --- when it moves upward, while fuzzy and granulated when it moves downward. The jet itself extends upward when the second shock front of the jet reaches the top of the jet. We find abrupt EUV brightenings when the second shock front collides with the edge of the jet. The third front and the fouth front quasi-periodically. These phenomena might be the signs of the rebound shock waves triggered by p-mode wave leakages at the bottom of the jets. Our observation suggests that the jet can be triggered by the rebound shock waves generated by the p-mode waves leaked at the bottom of the jets.

• 대한기계학회논문집B
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• 제23권9호
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• pp.1139-1150
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• 1999

The evolution of silica aggregate particles in coflow diffusion flames has been studied experimentally using light scattering and thermophoretic sampling techniques. The measurements of scattering cross section from $90^{\circ}$ light scattering have been utilized to calculate the aggregate number density and volume fraction using with combination of measuring the particle size and morphology through the localized sampling and a TEM image analysis. Aggregate or particle number densities and volume fractions were calculated using Rayleigh-Debye-Gans and Mie theory for fractal aggregates and spherical particles, respectively. Of particular interests are the effects of flame temperature on the evolution of silica aggregate particles. As the flow rate of $H_2$ increases, the primary particle diameters of silica aggregates have been first decreased, but, further increase of $H_2$ flow rate causes the diameter of primary particles to increase and for sufficiently larger flow rates, the fractal aggregates finally become spherical particles. The variation of primary particle size along the upward jet centerline and the effect of burner configuration have also been studied.

• 농업과학연구
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• 제44권2호
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• pp.261-271
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• 2017

The aim of this study was to investigate the amount of glucosinolates (GSLs) in kale sprouts (Brassica oleracea L. var. acephala) ('TBC') according to different concentrations of sulfur ions in sprout's nutrient solutions (0.0, 0.5, 1.0, and 2.0 mM) and to different light sources [Fluorescent lamp, Red, Blue, and Mix (R+B) LED]. Kale sprouts were cultivated in a growth chamber for 13 days in sulfur solutions. Kale sprouts were treated with fluorescent lamp and LED light sources for 5 days, from eight days after sowing to harvest. Amount of seven types of GSLs (progoitrin, sinigrin, 4-hydroxyglucobrassicin, glucobrassicin, 4-methoxyglucobrassicin, gluconasturtiin, and neoglucobrassicin) were measured in kale sprouts after harvest. The total GSL content was influenced by different sulfur solution concentration, and it was the highest at S 0.5 mM ($172.54{\mu}mol{\cdot}g^{-1}DW$) and the lowest at S 2.0 mM ($163.09{\mu}mol{\cdot}g^{-1}DW$). The GSL content was influenced by different light source, and it was the highest with Red LED ($159.23{\mu}mol{\cdot}g^{-1}DW$) and the lowest with Blue LED ($147.57{\mu}mol{\cdot}g^{-1}DW$). As the sulfur solution concentration increased under all light source, progoitrin and sinigrin contents tended to decrease while glucobrassicin content showed an upward tendency for all of the light sources. The content of glucobrassicin was higher than that of progitrin when treated with sulfur solutions for all LED light sources. Sinigrin, which has excellent anti-cancer effects, showed the highest rate (92.2%) among all the GSLs, under all of the light sources.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1998년도 제28회 추계학술대회
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• pp.166-174
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• 1998

The distribution of oil film thickness in piston were measured by induced fluorescence method. A Xe lamp was used as light source. Coumarine-6 was mixed with oil as the fluorescent dye. Fluorescent signal which is proportional to the oil film thickness was acquired by CCD camera and transmitted to the personal computer as video signal. In order to solve the problem of measurement system, irregular distribution and unstability of light intensity, as well as to know the relationship between the oil film thickness and output signal, three different calibration techniques were used. Motoring and firing tests were performed in a single cylinder research engine with transparent liner. By analyzing the oil film thickness converted from the photographed image, it was observed that each of three piston rings scrapes the oil both upward and downward and oil film thickness is not uniform horizontally at a given piston land. The amount of oil in each land was considerably affected by the engine load. It is thought that the blow-by gas blows the oil down to the crankcase.

• 천문학회보
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• 제41권1호
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• pp.41.3-42
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• 2016

New CCD photometric observations of GX Aur have been made between 2004 and 2015. Our light curves are the first ever compiled and display the variable O'Connell effect. The light variations are satisfactorily modeled by including time-varying cool-spots on the component stars. Our light curve synthesis indicates that the eclipsing pair is an A-type contact binary with parameters of i = 81.1 deg, ${\Delta}T=36K$, q = 0.950 and f = 46%. Including our 25 timing measurements, a total of 83 times of minimum light spanning about 66 yr were used for a period study. It was found that the orbital period of GX Aur has varied due to two periodic oscillations superposed on an upward-opening parabolic variation. The long-term period increase rate is deduced as $+9.636{\times}10^{-10}d\;yr^{-1}$, which can be produced as a mass transfer from the secondary star to the primary at a rate of $3.136{\times}10^{-6}M_{\odot}\;yr^{-1}$, among the largest rates for contact systems. The periods and semi-amplitudes of the two periodic variations are about $P_3=8.7yr$ and $P_4=21.2yr$, and $K_3=0.011d$ and $K_4=0.017d$, respectively. The most reasonable explanation for both cycles is a pair of light-travel-time effects driven by the possible existence of an unseen third and fourth components with projected masses of $M_3=0.91M_{\odot}$ and $M_4=1.09M_{\odot}$ in eccentric orbits of $e_3=0.13$ and $e_4=0.73$. Because no third light was detected in the light curve synthesis, each circumbinary object could be a compact star or a binary itself.

• 한국산학기술학회논문지
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• 제17권2호
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• pp.246-251
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• 2016

도로조명 중 누출광을 고려하지 않은 보안등이 아직도 많이 사용되어 주거지 침입광이 발생되고 있다. 이러한 도로조명의 침입광 저감을 위해 차광판이 설치되고 있지만, 효과가 미미하거나 미적 요소 및 안전성에 문제가 있다. 본 연구에서는 침입광 효율적인 저감을 위해 차광판 구조별 저감 특성을 연구하였으며, 그 방법으로 조명시뮬레이션 프로그램인 Relux 활용하였다. 또한 시뮬레이션의 값의 정확성을 알기 위해 실제 측정값과 검증하였다. 그 결과 (상)도색 글로브를 제외한 모든 차광판에서 후사광 저감 효과가 뛰어났으며, 도장형 차광판의 경우 전사광도 줄어들어 글레어 저감도 효율 적인 것으로 확인되었다. (상)도색 글로브는 위쪽으로 가는 빛을 아래로 반사시켜 후사광 전사광 모두 증가하였지만, 스카이 글로우(Sky glow) 저감에 효율적인 차광판으로 확인되었다. 시뮬레이션 값과 실측값은 90 %의 일치률을 보였다.

• 천문학회지
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• 제55권1호
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• pp.1-9
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• 2022

We present the photometric properties of V608 Cas from detailed studies of light curves and eclipse timings. The light curve synthesis indicates that the eclipsing pair is an overcontact binary with parameters of ∆T = 155 K, q = 0.328, and f = 26%. We detected the third light ℓ₃, which corresponds to about 8% and 5% of the total systemic light in V and R bands, respectively. Including our 6 timing measurements, a total of 38 times of minimum light were used for a period study. It was found that the orbital period of V608 Cas has varied in some combination of an upward parabola and two periodic variations. The continuous period increase with a rate of +3.99 × 10^-7 d yr^-1 can be interpreted as a mass transfer from the secondary component to the primary star at a rate of 1.51 × 10^-7 M_⊙ yr^-1. The periods and semi-amplitudes of the two periodic variations are about P₃ = 16.0 yr and P₄ = 26.3 yr, and K₃ = 0.0341 d and K₄ = 0.0305 d, respectively. The most likely explanation of both cycles is a pair of light-traveling time effects operated by the possible presence of third and fourth components with estimated masses of M₃ = 2.20 M_⊙ and M₄ = 1.27 M_⊙ in eccentric orbits of e₃ = 0.66 and e₄ = 0.52. Because the contribution of ℓ₃ is very low compared to the estimated masses of two circumbinary objects, they can be inferred as very faint compact objects.