• Journal of Ginseng Research
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• 제21권1호
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• pp.28-34
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• 1997

The effects of light on the pigment production and chloroplast development were examined on ginseng hairy roots cultured in 1/2MS liquid medium. The chlorophyll and carotenoid production were increased from 1,000 to 3,500 lux condition, but decreased drastically in 7,000 lux condition. The anthocyanin production was significantly increased with increment light intensity(1,000∼7,000 lux). The thylakoid membrane of chloroplast was proplastid in dark condition and it began to develop into thylakoid membrane in 1,000 lux condition and then intact thylakoid membrane was developed in 3,500 lux condition. However, the development of thylakoid membrane in 7,000 lux condition was inhibited comparing to 3,500 lux condition. The total chlorophyll production in blue light condition were high comparing to other wavelength and same as 40% of total chlorophyll on white light(3,500 lux) condition. The chlorophyll and carotenoid production by sucrose concentration were high in 3% sucrose condition and anthocyanin production was high in 4% condition. The production of chlorophyll and carotenoid by light periods was high when explants were cultured in dark condition for 1 week and then transferred to light condition for 4 weeks. Our results suggest that pigment production and chloroplast development could be accelerated by light Intensity of specific wavelength in cultures of ginseng hairy root.

• 식물조직배양학회지
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• 제22권2호
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• pp.71-76
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• 1995

자리공 모상근에서 광처리에 따른 항산화효소의 활성을 조사하였다. Catalasa superoxide dismutasae, ascorbate oxidase (AO)의 활성은 광도가 2,000 lx까지 증가할수록 감소하였으며, 특히 AO활성은 2,000 lx에서 암상태보다 92% 감소하였다. Glutathione reductase, glutathione peroxidase (GPO), ascorbate peroxidase 그리고 peroxidase의 활성도는 500 lx까지는 광도가 높아질수록 증가하였으나 그 이상의 높은 광도에서는 현저하게 감소하였다. GPO의 활성은 AO처럼 2,000 lx에서 암상태보다 85%감소하였다. 광파장에 따른 항산화효소의 활성은 청색광의 파장에서 가장 많이 억제되었으며, AO의 활성은 25%까지 감소하였다. 청색광 파장의 광도에 따른 항산화효소의 활성도는 30 lx까지는 증가하다가 200 lx에서는 암상태보다 21-71%까지 감소하는 경향을 나타내었다. AO의 활성은 청색 파장의 광도(300-200 lx)가 증가할수록 급격히 감소하여 200 lx에서는 70%까지 억제되었다. 자리공 모상근의 항산화효소 활성은 청색광 파장의 높은 광도에서 주로 생성된 유해산소 의하여 억제되고 있음을 확인하였다. 광상태하에서 모상근의 생장과 betalain 합성을 향상시키기 위해서는 모상근에서 생성되는 산화제의 효율적인 제거가 요구됨이 시사되었다.

• 한국전기전자재료학회논문지
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• 제23권9호
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• pp.708-713
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• 2010

In this research a ring light was developed so that a partial shadowless shooting for the patient's affected area at the medical treatment room and surgical operation room using high luminance light emitting diode (LED) for which attention is being paid as new lighting parts for medical purpose. LED which was applied to the development used high luminance three color LED for full color for which various color materialization and the adjustment of radiation intensity are possible and we can get white light in order to emphasize the delicate expression for generic tone of shooting object, strong highlight, simple shadow and three dimensional effect at the time of close-up shadowless shooting of the affected area. And at the time of design of ring light, the characteristics of LED and the loss of light at the time of penetrating light diffusion PC were considered so that intensity of illumination for over 150 lx can be obtained. The result of measurement of the intensity of illumination of the ring light that was developed revealed that maximum intensity of illumination of 225.7 lx was obtained, while smoke index was measured to be maximum 78 Ra in the case of Red(50%) Green(100%) and Blue LED(60%). We could confirm that response speed was also very fast as 1.72 ms.

• Journal of Photoscience
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• 제9권2호
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• pp.13-16
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• 2002

A comparison of the functional components underlying photoperiodism and circadian rhythmicity in the same species is an interesting issue in the context of unravelling clock mechanisms. In the present study, covering or surgical removal of the compound eyes was performed to localize photoreceptors for photoperiodism to control reproductive diapause and for entrainment of circadian locomotor rhythms in the blow fly Protophormia terraenovae. Intact flies showed a long-day photoperiodic response. When the compound eyes were covered by silver paint, diapause incidence increased under diapause-averting conditions of a long-day photoperiod and constant light, as if flies were kept under constant darkness. Covering of a medial region of the head capsule or solvent painting of the compound eyes gave no significant effects. When the compound eyes were removed, flies did not distinguish the photoperiod, whereas removal of antennal lobes or ocelli did not affect the photoperiodism. Intact flies showed a freerunning rhythm under constant darkness. The rhythm entrained to light-dark (LD) cycles with light of high and low intensity. When the compound eyes and ocelli were surgically removed, the rhythm entrained to LD cycles with light of high intensity but freeran under LD cycles with light of low intensity. The results suggest the retinal pathways are involved in photoperiodism and that flies use both retinal and extraretinal pathways for rhythm entrainment. Under dim light-LD cycles, the retinal pathways mainly mediate rhythm entrainment. Retinal photoreceptors seem to be used both for photoperiodism and entrainment of the rhythm.

• 전기학회논문지
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• 제65권7호
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• pp.1225-1230
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• 2016

Since a flash light produces enormous amount of photon energy in short time, not only electro-optic and infrared(EO/IR) systems utilized for Intelligence Surveillance Target Acquisition and reconnaissance(ISTAR) activities but also the people of a combat field can be severely influenced by a high flash light bursting in front of them. The people who bumped into a flash could not escape such enormous amount of photon energy, resulting in being blind temporarily or even permanently. In order to investigate the effect of a high flash source on a human eye, it is essential to know how much photon energy be incident into an eye from the flash source. In this paper, the model of irradiated photon energy to individuals from some flashes is proposed. The proposed irradiated photon energy per unit area of retina is based on taking the situation to be modeled as a simple EO system in front of a flash light. The validity of proposed model was proved by the application of the model to human on the surface of the earth with the well known light source, the Sun. The model of this study can be utilized to simulate the retinal intensity and energy of a flash for various conditions such as the illumination levels, the distance from a flash busting site, luminous intensity and time of a flash.

• International Journal of Control, Automation, and Systems
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• 제3권1호
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• pp.130-136
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• 2005

A new optical digitizing system for determining the position of a cursor in three dimensions(3D) and an experimental device for its measurement are presented. A semi-passive system using light intensity modulation, a technology that is well known in radar ranging, is employed in order to overcome precision limitations imposed by background light. This system consists of a charge-coupled device camera placed before a rotating mirror and a light-emitting diode whose intensity is modulated. Using a Fresnel pattern for light modulation, it is verified that a substantial improvement of the signal to noise ratio is realized for the background noise and that a resolution of less than a single pixel can be achieved. This opens the doorway to the realization of high precision 3D digitized measurement. We further propose that a 3D position measurement with a monocular optical system can be realized by a numerical experiment if a linear-period modulated waveform is adopted as the light-modulating one.

• 천문학회보
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• 제44권1호
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• pp.58.3-58.3
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• 2019

Optical intensity interferometry, developed in the 1950s, is a simple and inexpensive method for achieving angular resolutions on microarcsecond scales. Its low sensitivity has limited intensity interferometric observations to bright stars so far. Substantial improvements are possible by using avalanche photodiodes (APDs) as light detectors. We present here the results of laboratory measurements with a prototype astronomical intensity interferometer using APDs in continuous ("linear") detection mode - arguably, the first of its kind. We used two interferometer configurations, one with zero baseline and one with variable baseline. Using a superluminous diode as light source, we unambiguously detected Hanbury Brown-Twiss photon-photon correlations at very high significance. From measuring the correlation as function of baseline, we measured the angular diameter of the light source, in analogy to the measurement of the angular diameter of a star. Our results demonstrate the possibility to construct large astronomical intensity interferometers that can address a multitude of astrophysical science cases.

• 한국환경과학회지
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• 제16권11호
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• pp.1313-1318
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• 2007

Illicium anisatum was bred under four different light intensity. Those condition were full sunlight(PPFD $1600{\mu} mol\;m^{-2}s^{-1}$), 30% treatment(PPFD $400{\mu} mol\;m^{-2}s^{-1}$), 50% treatment(PPFD $250{\mu} mol\;m^{-2}s^{-1}$) and 70% treatment(PPFD $100{\mu} mol\;m^{-2}s^{-1}$), respectively. Chlorophyll a and b were increased according to decrease of light intensity. Thirty percent and 50% treatment had not significant different in chlorophyll a and b. Thirty percent treatment was shown the best photosynthetic activity through invested photosynthetic rate, intercellular $CO_2$ concentration and water use efficiency. Photosynthetic activity trend of 50% treatment was similar to 30% treatment. Seventy percent treatment was shown the best photosynthetic activity at low light intensity but that was decreased to lower value than 30% and 50% treatment under high intensity. Control, bred full sunlight, was shown the worst photosynthetic activity at measured all light intensity. That result could imply that was caused by photo-inhibition because of long term exposed of shade tolerant plant at high light intensity. Leaf characteristics had not significant different in leaf length, width and area but leaf dry weight had similar trend to photosynthetic activity.

• 조명전기설비학회논문지
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• 제18권3호
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• pp.20-26
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• 2004

본 논문에서는 조명용 고휘도(HB, high brightness) 백색 LED(light emitting diode)램프의 배열 및 여러 가지 등기구 글로브(globe)의 형태에 따른 광도(luminous intensity)값과 기구효율(luminaire efficiency)을 컴퓨터 시뮬레이션으로 수행하여 비교분석 하였다. 즉, LED의 배열은 가로${\times}$세로(7개${\times}$7개)가 정사각형 형태로 49개를 배열하고, LED 간격은 LED의 발광면 중심부로부터 8.2[mm], 10.0[mm], 15.0[mm]로 각각 3가지로 하였으며, 등기구의 글로브는 LED발광면 중심부에서 30[mm], 50[mm] 떨어진 거리로 구분하였다. 또한 등기구 글로브가 없을 때와 있을때로 구분하여 있을 때에는 글로브 형태를 볼록 원형과 엠보(embossing)형태로 구분하고 엠보는 8.2[mm], 5.0[mm]의 크기에 따른 선택으로 시뮬레이션 27가지로 수행하여 등기구의 글로브 형태에 따른 광도 및 기구효율을 고찰해 봄으로써 앞으로 21세기 디지털조명이라고 일컫는 LED를 사용한 LED 광원(light source) 및 등기구 개발에 많은 도움이 되고자 하였다.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2005년도 춘계학술대회논문집
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• pp.14-18
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• 2005

It is important to select light sources and luminaires in the process of lighting design. Therefore, development of light sources has been constantly grown for a high efficacy and long life. And, the design of luminaires has been developed for the reflection of light mechanism. But it has been not enough to study for the refraction of light mechanism Therefore, the propose of this study is to study for the refraction of light mechanism. In addition, this study is modeling for the luminous intensity distribution of planar prism to use the results of photometric data that is able to obtain various luminous intensity distribution.