• Korean Journal of Plant Resources
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• v.12 no.2
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• pp.139-144
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• 1999

The present study was carried out to determine the effects of lighting directions and light intensities on the growth of in vitro plantlets of strawberry, potato and lily. The growth of plantlets was affected by two different lighting systems, downward and sideward lighting system. There were no difference for the plantlets of strawberry regardless of lighting directions. However, leaf area, fresh weight and dry weight have increased as the light intensity increased. Also, plant height and root length on node culture of potato decreased at high intensity of the sideward lighting, while thickness of stem and root was thicker, fresh weight and dry weight were heavier, and leaf area was increased. Also, bulblet formation on scale culture of lily has been abundant, and fresh weight and dry weight were increased. Thus, the sideward lighting system which loaded three stories for culture vessels with raising light intensity into culture vessels instead of conventional downward lighting system promoted growth and raised the efficiency of production of high quality microplant.

• Korean Journal of Optics and Photonics
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• v.32 no.4
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• pp.180-186
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• 2021

Fluorinated polyimide has excellent light transmittance and a high optical refractive index, and is useful for producing optical-waveguide phase modulators with low optical loss and low electric power consumption. In this work, an optical-waveguide phase modulator is designed and fabricated based on a high-refractive-index fluorinated polyimide, and its characteristics are measured. An efficient protocol for characterizing the loss components of the optical waveguide is proposed, and the propagation loss of the fabricated polyimide optical waveguide is confirmed to be 0.9 dB/cm. The phase modulator requires 9.1 mW of power for phase change of π, and the response time is 290 μs, which is improved by tenfold compared to a previous demonstration of polymeric phase modulators.

• Journal of Bio-Environment Control
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• v.18 no.4
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• pp.431-435
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• 2009

This study was conducted to compare the effect of various LED and UVa light to enhanced coloration of paprika fruits cultivars; 'Special', 'Helsinki'. Immatured paprika fruits were irradiated with red LED, blue LED and UVa lights which were high intensity (red: $50{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, blue: $70{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, UVa: $3{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) and low intensity (red: $20{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, blue: $40{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, UVa: $0.25{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$). The coloration of 'Special' cultivar was increased the fastest in high intensity UVa light for 2 days after treatment. There were no significantly difference among treatments except the low intensity UVa light. The coloration of 'Helsinki' was increased the fastest in blue LED light, and followed by red LED light and UVa light for 2 days after treatment. The $a^*/b^*$ value of 'Special' and $b^*$ value of 'Helsinki' that indicated the paprika fruit coloration were generally higher high intensity LED and UVa lights than low intensity LED and UVa lights. We couldn't find out any significantly different coloration effect among all treatments in final days of coloration. and rather than UVa treatment fruit shrunk the surface of paprika fruits.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.141-141
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• 2003

전기-광 효과를 이용한 광변조기, 스위치 등의 소자 구현을 위해 고품질의 Ti:LiNbO$_3$ 광도파로 제작은 필수적이다. LiNbO$_3$ 광도파로는 양자교환(APE) 및 Ti 확산 법으로 제조할 수 있으며 전자의 경우 ne 는 증가, no는 감소되는 경향이 있어 편광도 파로의 제작에 용의하며 후자의 경우 ne 와 no 모두 증가하는 도파로 특성을 갖는다. 이러한, 도파로 소자의 특성 향상을 위해서는 Li out-diffusion 이 억제된 손실이 적은 도파로 제작이 필수적이다. 본 연구에서는 Ti 내부 확산법을 이용한 LiNbO$_3$ 광도파로를 확산분위기를 조건으로 하여 제작하였으며, 온도에 따른 각 이온의 반응 메커니즘에 관하여 관찰하였다.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.53.1-53.1
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• 2014

본 연구에서는 고궤도 및 원거리 우주물체의 추적 및 관측이 용이한 광학관측 시스템을 이용하여 정지궤도위성을 관측하였고, 광도곡선 분석을 통해 식별정보를 획득하였다. 정지궤도 위성은 자세에어 방법에 따라 회전 안정화 위성과 3축 안정화 위성으로 나뉘며, 3축 안정화 위성은 다시 통신위성과 지구관측 위성 등으로 나뉜다. 회전 안정화 위성의 식별 연구를 위해 중국의 FY-2 위성을 관측대상으로 선정하였고, 3축 안정화 위성의 식별을 위해 한국의 COMS-1 위성을 관측 대상으로 선정하였다. 회전안정화 위성은 Sidereal Tracking Mode로 관측하면 위성의 궤적이 선 모양으로 나타난다. 이때 나타난 궤적의 pixel value 값을 확인하면 일정한 주기로 밝기가 변화 하는 것을 확인할 수 있으며, FFT를 수행하면 위성의 회전율과 회전 주기를 구할 수 있다. 3축 안정화 위성은 Stare Mode로 관측하여 측광하면 광도곡선을 획득할 수 있다. 위성의 형상을 결정하는 본체, 안테나, 태양전지판을 모델링하여 광도곡선 시뮬레이션결과와 비교하면 각각의 형상이 광도곡선에 미치는 영향과 특징을 알 수 있고, 이를 통해 식별정보를 획득할 수 있다. 이상의 분석을 통해 얻은 FY-2위성과 COMS-1 위성의 식별정보를 제시하고 향후 우주물체 식별 연구에 활용하고자 한다.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.36D no.5
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• pp.69-79
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• 1999

In this paper, we proposed a diffuion model of Ti diffused lithium niobate optical waveguide for fabricating waveguides with high refractive index and compared with conventional one. The achivement of low optical insertion loss between waveguide interface and single mode fibers was discussed as a function of Ti thickness for $\lambda$=1.55$\mu\textrm{m}$ The proposed diffusion method exhibited higher refractive index waveguide than conventional one for $\lambda$=0.6328$\mu\textrm{m}$ We have achieved the total fiber-waveguide-fiber insertion loss as low as 0.5dB/cm in z-cut and 1$\pm$0.5dB/cm in x-cut for both TM and TE mode of Mach-Zehnder interferometric waveguide in the range of Ti thickness 1000-1400$\AA$ for $\lambda$=1.55$\mu\textrm{m}$ From these results, this diffusion model for making a low loss waveguide can be used for low-power-modulators and switches.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.2 no.4
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• pp.32-37
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• 1988

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.4
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• pp.386-391
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• 1987

Effect of growth light intensity (5% and 20%) and planting density (40, 56, 90/33㎡) on yield and red ginseng quality was investigated in a sandy loam field of ginseng plantation. High growth light intensity had no effect on yield and quality but decreased stem length, leaf area and chlorophyll content and increased specific leaf weight. The optimum planting density was 64/3.3㎡ for both yield and Heaven + Earth grade (HE grade) of red ginseng. HE-shape ginseng rate showed significant positive correlation (P=0.0l) with HE grade rate.

• Journal of the Korean Society for Nondestructive Testing
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• v.33 no.4
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• pp.376-381
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• 2013

위상잠금 열화상에서는 일반적으로 변조된 주파수의 광램프를 쓰고 있다. 하지만 램프의 광도 분포는 입력신호가 평단(flat)특성임에 불구하고 심지어 불균일하여 검사 시편내에 측면 열유동을 만들어낸다. 이러한 열유동은 원치 않는 효과로서 측면의 분해능을 감소시키는 등과 같이 관심 결함구조의 영상에 부정적인 영향을 미친다. 본 고에서 검토되는 방식은 열원으로서 LCD 프로젝터와 같은 것을 이용하여 각 가진픽셀에 개별적으로 진동진폭, 광도 오프셋, 위상지연 등을 할당하는 방법에 대한 접근기술이다. 이러한 반복적인 자체학습 과정에 의한 조명 패턴을 통하여 측면 열유동이 제거되고 분해능이 향상되도록 제공하는 것이다.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.4
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• pp.638-642
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• 2001

Recently, plasma arc curing system for curing resin composites has been introduced. This is characterized by a high output of light energy, which has the advantage of reducing the chair time and thereby making the treatment more comportable for the patients as well as for the dentist. The purpose of this study was to compare the shear bond strengths of light-cured orthodontic adhesive polymerized with conventional halogen light and plasma arc light. The 2 curing devices used were the XL3000 (3M, USA) conventional curing light and the Flipo (LOKKI, France) plasma arc light. The results from the present study can be summarized as fellows; 1. The mean shear bond strength for three groups were quite similar for 50 second conventional light group, 2 second plasma arc curing light group, 5 second plasma arc curing light group. 2. There was no statistically significant difference for three groups(p>0.05).