• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.4
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• pp.475-483
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• 2015

We examined the effects of light colors (wavelength) and light quantities on the yield ratio and quality of cultivated cowpea sprouts. All light colors resulted in a lower cowpea sprout yield ratio compared to the untreated condition (darkness), but were similar in hard seed ratio. All light colors promoted the growth of the epicotyl and root when compared to the untreated condition, but limited the growth of the hypocotyl. White light (458 nm) significantly improved grade by increasing the lightness of the cotyledon and the hypocotyl and the yellowness of the hypocotyl. The Fe content of cowpea sprouts was higher in those grown under red light (632 nm), and the total amino acid content was higher for those grown under yellow light (560 nm), white light (458 nm), and blue light (460 nm) compared to plants grown in the untreated condition (darkness). The yield ratio of cowpea sprouts was lower in the yellow light condition (560 nm) at lower light quantity, but no differences were observed at other light colors and quantities. The lightness and yellowness of cowpea sprouts was higher in the yellow light (560 nm) and red light (632 nm) at lower light quantity, redness was lower. No significant differences were observed in the content of normal and inorganic components according to the light quantities of each light color, except that Fe content was higher in sprouts grown under red light (632 nm) as light quantity increased. Total amino acid content was slightly higher in sprouts grown under white light (458 nm) and blue light (460 nm) as light quantity increased.

• Korean Journal of Optics and Photonics
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• v.33 no.6
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• pp.324-330
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• 2022

We measured the Dill and Mack model parameters that determine the exposure and development characteristics of photoresists, respectively. First, photoresist samples were prepared while altering the exposure dose, and changes in transmittance were measured. Analyzing these results, the Dill model parameters A, B, and C were determined. In particular, the exact solution of the Dill model equation was used to determine the C parameter. In addition, changes in thickness were measured as a function of development time for different exposure doses, and the Mack model parameters R_min, R_max, a, and n were determined using the results. We also determined parameter values for the reduced Mack model that uses only three parameters, R_min, R_max, and n. The root mean square error between the model predictions and the measured values for the photoresist thickness was found to increase slightly compared to the case using the original Mack model with four parameters.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.101-101
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• 1999

실시간으로 변화하는 시료를 측정하고 분석할 수 있도록 비접촉시이며, 광학방식인 단파장 in situ 타원해석기를 제작하였다. He-Ne 레이저를 광원으로 사용하였고 회전편광자형 광량 측정방식을 채택하였다. 기존의 진공챔버 등에 쉽게 장착할 수 있도록 동축 구조를 사용하였으므로 소형이며 단순한 설계가 가능하였다. 전자빔 증착방법으로 성장시킨 조밀도가 82%인 이산화티타늄 박막의 분석에 이 타원해석기를 사용하여 수분탈착에 따르는 이산화티타늄 박막의 유효밀도 변화를 박막의 온도 변화와 시간 변화에 따라 실시간 in, situ방식으로 관측하였다.

• Journal of Plant Biology
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• v.38 no.4
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• pp.373-380
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• 1995

Photoinhibition of photosystem (PS) n was induced in primary leaves of 25 day-old peppers grown $100\;{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1},\;at\;25^{\circ}C$. The modulation of PSII functionality in vivo was induced by varying both irradiance ($0-3000\;{\mu}molm^{-2}{\cdot}s^{-1}$) and duration (0-70 min) of light treatment. The functionality of PSII was investigated in terms of photochemical efficiency of PSII (Fv/Fm) and quantum yield of $O_2$ evolution, and expressed as a function of photon exposure [$mol\;photons{\cdot}m^{-2}$, the product of irradiance and duration of light treatment (Bell and Rose, 1981)]. Contrary to the linear decline of Fv/Fm ratio showing 50% decreases by absorption of $10\;mol\;photons{\cdot}m^{-2$, quantum yield of $O_2$ evolution decreased biphasically with increasing photon exposure, showing 50% decreases by absorption of $5.5\;mol\;photons{\cdot}m^{-2}$. Treatment of low temperature at $15^{\circ}C$ for 30 min alone did not affect the functionality of PSII, but high temperature ($45^{\circ}C$) significantly inactivated PSII activity. However, when Jeaves of pepper were subjected to low or high temperature in the presence of light, PSII was substantially photoinactivated. These results suggest the presence of different photoinhibitory mechanisms at low and high temperature.rature.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.7
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• pp.17-22
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• 2008

This paper presents a low-power and small-area pulse width modulator by light intensity for photoflash. Light intensity controller is achieved by using capacitor, photodiode, and comparator. The proposed circuit designs digital circuit to reduce static power consumption except comparator. And IGBT driver has short circuit protection using delay cell. The pulse width modulator has the operating range of $V_{MS}$ from 0.5V to 2.5V and pulse width of output from 0.14ms to 1.65ms at 300Hz. The pulse width modulator fabricated in $0.35-{\mu}m$ CMOS technology occupies $0.85mm{\times}0.56mm$. This circuit consumes 3.0mW at 300Hz and 3.0V.

• Journal of Korea Multimedia Society
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• v.5 no.2
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• pp.215-221
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• 2002

In high speed optical disc devices, the vibration caused by unbalanced displacement leads the focus and tracking servo systems to be unstable, and increases the data search time. In this paper, we propose a new scheme to solve the unbalanced displacement problem. The proposed method detects the unbalanced rate by differential amplifying optical power received at photo diode and converts it into an electrical signal. controlling the speed of spindle motor, according to the detected unbalanced rate, makes it possible to improve the performance of tracking and data searching tasks. Also, we analyze the dynamic characteristics of focus and tracking servo systems in high speed mode and provide the firmware and hardware architecture that the proposed method can be installed as an add-on- module in the existing system.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.555-556
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• 2008

본 연구에서는 레이저빔 투과를 이용한 본딩 웨이퍼 검사 방법을 제안하고 검사 장치를 설계 구현하였다. 1064nm 파장에서의 정상웨이퍼를 일정한 비율로 투과 하였다. 본딩 불량으로 인한 웨이퍼의 기공은 두께에 따라 투과율이 현저하게 변화하여 기공 부분을 검출하였다. 이러한 기공은 두께의 변화가 있으며 광량의 변화하는 부분이 에어갭으로 인식 카메라로 쉽게 구분이 가능하였다.

• Proceedings of the KIPE Conference
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• 2009.11a
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• pp.129-131
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• 2009

급속하게 발전하는 태양광발전산업에 맞추어 태양광발전시스템의 시험단계에 필요한 태양전지의 전압-전류 특성을 가지는 태양전지 시뮬레이터는 필수적이다. 이를 위해 본 논문에서는 기존의 방법과 달리 태양전지모듈의 표준시험 조건의 출력데이터와 주요 온도별, 광량별 데이터, 관계변수만을 가지고 온도와 광량의 변화에 따른 새로운 전류, 전압곡선 추출방법을 간단한 수식을 통해 해석하고, 하드웨어를 구성하여 다양한 조건에서 태양전지의 I-V Curve를 시뮬레이션 한다. 15kW급 태양전지 시뮬레이터의 시작품을 제작하여 실험을 통해 제안된 방법의 타당성을 검증한다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2012.07a
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• pp.229-231
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• 2012

본 논문에서는 펄스옥시미터 시스템의 측정 신뢰성 향상을 위해 Perfusion Index값을 이용한 광량조절의 방법을 제시한다. 본 방법은 펄스옥시미터의 광출력 값의 조정을 미약한 신호 상황에 대한 적응 가능한 광출력을 줄 수 있으며, 산소포화도 측정값의 변화율에 직접적으로 영향을 주는 광량을 보다 정확하게 조절하여 안정적인 측정이 가능하다. 또한 미약한 신호의 측정을 일괄적으로 조절 가능한 기능을 통해 다양한 사람들에게 사용되는 펄스옥시미터의 특성상 보다 정확한 값을 제공할 수 있다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.471-472
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• 2005

본 연구는 TFT-LCD의 배경광원인 Backlight Unit(BLU)의 구조를 광학 시뮬레이션을 통하여 분석함으로써 BLU에서의 광효율을 극대화하는데 초점을 두었다. 일반적으로 LCD Monitor BLU는 형광램프, 반사시트, 램프 리플렉터, 도광판, 광학시트로 구성된다 여기에서는 20.1 인치 6램프로 구성된 Monitor용 Side Type BLU에 대하여 램프 리플렉터의 형상, 램프 리플렉터의 내부 공간 변화와 그에 따른 램프의 위치, 램프사이의 배열에 따른 램프에서 도광판으로의 입사광량을 광학 시뮬레이션을 통하여 분석하였다. 위 시뮬레이션의 결과, 램프리플렉터가 'ㄷ' 형상일 때, 램프리플렉터 내부공간의 약 1:2 되는 지점에 램프가 위치하고 Center Lamp가 도광판에 최대한 가깝게 위치할 때 입사광량이 최대가 되어 BLU에서의 광효율이 향상됨을 알 수 있었다.