• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2018년도 춘계학술발표회
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• pp.66-66
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• 2018

Light fermentation has been conducted under different light conditions such as normal dark light, white light, and light emitting diodes (LEDs) various color (blue, green, red, white on blueberry powder with fermenting bacteria Bacillus subtilis (B2). The bacteria B2 was isolated and identified by 16S rRNA sequencing method. RYRP biologically converted to secondary metabolites through light fermentation in the presence of Bacillus subtilis, the bacteria actively involved in bioconversion process. LEDs fermentation to enhance the production of phenolic content while comparing to normal dark and white light. Among the different color LEDs, blue LEDs mediated fermentation showed higher amount of total phenolic and flavonoid content. Then blue LEDs mediated fermented compound were characterized by FTIR and GC-MS, subsequently the compound was analyzed antioxidant activity tests and the antioxidant activity exhibited higher. This is the first study to demonstrate that B. subtilis-LEDs mediated fermentation is useful for facilitating phenolic compound production and enhancing antioxidant activity, which may have greater application fermentation fields.

• 원예과학기술지
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• 제31권1호
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• pp.14-23
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• 2013

This study evaluated the influence of light quality and intensity during healing and acclimatization on the $CO_2$ exchange rate, growth, and morphogenesis of grafted pepper (Capsicum annuum L.) transplants, using a system for the continuous measurement of the $CO_2$ exchange rate. C. annuum L. 'Nokkwang' and 'Tantan' were used as scions and rootstocks, respectively. Before grafting, the transplants were grown for four weeks in a growth chamber with artificial light, where the temperature was set at $25/18^{\circ}C$ (light/dark period) and the light period was 14 hours $d^{-1}$. The grafted pepper transplants were then healed and acclimatized under different light quality conditions using fluorescent lamps (control) and red, blue, and red + blue light-emitting diodes (LEDs). All the transplants were irradiated for 12 hours per day, for six days, at a photosynthetic photon flux (PPF) of 50, 100, or 180 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. The higher PPF levels increased the $CO_2$ exchange rate during the healing and acclimatization. A smaller increase in the $CO_2$ exchange rates was observed in the transplants under red LEDs. At a PPF of 180 ${\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, the $CO_2$ exchange rate of the transplants irradiated with red LEDs was lowest and it was 37% lower than those irradiated with fluorescent lamps. The $CO_2$ exchange rates of transplants irradiated with blue LEDs was the highest and 20% higher than those irradiated under fluorescent lamps. The graft take was not affected by the light quality. The grafted pepper transplants irradiated with red LEDs had a lower SPAD value, leaf dry weight, and dry matter content. The transplants irradiated with blue LEDs had longer shoot length and heavier stem fresh weight than those irradiated with the other treatments. Leaves irradiated with the red LED had the smallest leaf area and showed leaf epinasty. In addition, the palisade and spongy cells of the pepper leaves were dysplastic and exhibited hyperplasia. Grafted pepper transplants treated with red + blue LEDs showed similar growth and morphology to those transplants irradiated with fluorescent lamps. These results suggest that high-quality grafted pepper transplants can be obtained by healing and acclimatization under a combination of blue and red lights at a high PPF level.

• 한국유기농업학회지
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• 제23권3호
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• pp.549-565
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• 2015

LEDs 광원 및 광도에 따른 베이비채소 6작물의 생육 특성과 기능성물질 함량을 구명하고자 Fluorescent lamp (100, 125, $150{\mu}mol\;m^{-2}s^{-1}$), Red+Blue 1:1 (100, 125, $150{\mu}mol\;m^{-2}s^{-1}$), Red+Blue 2:1 (100, 125, $150{\mu}mol\;m^{-2}s^{-1}$), Red+Blue 4:1 (100, 125, $150{\mu}mol\;m^{-2}s^{-1}$) 광원하에서 파종 40일 후에 수확하여 조사한 결과는 다음과 같다. 1. 베이비채소의 엽수는 시금치를 제외한 비트, 치커리, 적상추, 쑥갓, 겨자에서 Red+Blue(4:1) $150{\mu}mol\;m^{-2}s^{-1}$ 처리에서 가장 많았다. 2. 초장은 비트를 제외한 치커리, 시금치, 적상추, 쑥갓, 겨자에서 Red+Blue(4:1) $150{\mu}mol\;m^{-2}s^{-1}$ 처리에서 가장 높았다. 3. 생체중과 건물중은 비트, 치커리, 시금치, 적상추, 쑥갓, 겨자에서 Red+Blue(4:1) $150{\mu}mol\;m^{-2}s^{-1}$ 처리에서 가장 높았다. 4. 엽록소 a, 엽록소 b 함량은 시금치, 적상추, 겨자가 대조구인 Fluorescent lamp $150{\mu}mol\;m^{-2}s^{-1}$에서 가장 높았다. 5. 총 안토시아닌과 총 폴리페놀 함량은 비트, 치커리, 시금치, 적상추, 쑥갓, 겨자에서 Red+Blue(4:1) $150{\mu}mol\;m^{-2}s^{-1}$ 처리에서 가장 높았다. 6. Free radical 소거능은 비트, 치커리, 시금치, 적상추, 쑥갓, 겨자의 $150{\mu}mol\;m^{-2}s^{-1}$에서 높았지만 LEDs 광원별로는 차이를 보이지 않았다. 이상의 결과를 종합해 볼 때 비트, 치커리, 시금치, 적상추, 쑥갓, 겨자의 베이비 채소를 Red+Blue (4:1) $150{\mu}mol\;m^{-2}s^{-1}$에서 재배한다면 더욱 좋은 생육 효과를 기대할 수 있고 기능성 물질 함량도 다른 광도와 비교하여 상대적으로 좋았으므로 추후 상기의 베이비채소 생산 시 유용한 기초자료가 될 것으로 생각된다.

• 한국광학회:학술대회논문집
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• 한국광학회 2009년도 동계학술발표회 논문집
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• pp.509-510
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• 2009

The optical gain of InGaN/GaN multi quantum well (MQW) resonant-cavity light-emitting diode (RC-LED) with different Indium composition and well width in the multi-quantum well was investigated. The optimized optical gain was obtained by simulating active region InGaN/GaN with some test values of well width and Indium composition. By simulation tool, we could simulate on several cases, and then we got exact well width and Indium composition that makes optical gain maximum due to the short wavelength of 470 nm for blue light emission.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2003년도 추계학술발표강연 및 논문개요집
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• pp.198-198
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• 2003

LED(Light Emitting Diode)는 전기 신호를 빛으로 신호를 보내고 받는데 사용되는 반도체의 일종으로 가정용 가전제품, 리모컨, 전광판, 각종 자동화 기기등에 사용된다. 3색광 백색 LED는 soft-UV 또는 blue 빛을 내는 device 와 RGB 형광체로 이루어져 있다. 현재 연구중인 3색광 백색 LED는 InGaN 또는 GaN 이 RGB 형광체를 여기 시키는것이 대부분이다. 이러한 경우에 유기물과 무기물 형과체가 백색광을 구현하기 위해 사용된다. 유기물의 경우에는 lift-time 이 짧고, 무기물의 경우에는 유해원소인 S, Cd등이 포함되기 때문에 환경오염이 야기된다. 이러한 단점을 보완하기 위해 진화 최적방법을 이용하여 alkali earth borosilicate ((Eu,Mg,Ca,Sr,Ba)$_{x}$ $B_{y}$ S $i_{z}$ $O_{d}$ ) 계열에 $^{Eu3+}$을 도핑하여 고효율 형광체를 합성하였다.

• Applied Science and Convergence Technology
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• 제25권1호
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• pp.1-6
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• 2016

Quantum dots (QDs) are considered as excellent color conversion and self-emitting materials for display and lighting applications. In this article, various technologies which can be used to realize white light emission with QDs are discussed. QDs have good color purity with a narrow emission spectrum and tunable optical properties with size control capabilities. For white light emission with a color-conversion approach, QDs are combined with blue-emitting inorganic and organic light-emitting diodes (LED) to generate white emission with high energy conversion efficiency and a high color rendering index for various display and lighting applications. Various device structures for self-emitting white QD light-emitting diodes (QD-LED) are also reviewed. Various stacking and patterning technologies are discussed in relation to QD-LED devices.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.286.1-286.1
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• 2013

Nowadays, the glare towards the light-emitting diode (LED) lighting source has much attention due to its eco-friendly nature, reduced energy consumption, and low CO2 emission. LEDs can show versatile colors by changing the composition ratio of semiconductors. Phosphors re-emit light by absorbing light from LED, which is the key factor for emission. The endeavor to make replica of natural white light is increasing day by day. Industrially, blue LED chip crowned with a yellow phosphor coated lens gives low quality white light. Newly, many researchers are introducing modern approaches, adding red phosphor to the yellow phosphor to increase the quality of white light. Here, we synthesized structurally and chemically stable europium doped oxyapatite Ca8Gd2(PO4)6O2 nano-crystalline structures by a hydrothermal method. The ultrafine structures were formed due to the effect of ethylenediaminetetraacetic acid, which is confirmed by the transmission electron microscope images. The structural properties were analyzed using the X-ray diffraction patterns.

• 한국농림기상학회:학술대회논문집
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• 한국농림기상학회 2013년도 추계 학술발표논문집
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• pp.25-25
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• 2013

식생의 생물계절학적 특성은 지표면과 대기의 에너지와 물 순환에 큰 영향을 미친다. 일반적으로 상층군락과 하층군락의 식생은 미기후의 차이 등에 의해 서로 다른 생물계절학적 특성을 가진다. 이러한 식생의 생물계절학적 특성은 반사도 관측을 통해 추정할 수 있다. 과거부터 원격탐사 기법을 활용하여 식생의 생물계절학적 특성을 추정하는 많은 연구가 수행되어 왔다. 그러나 대부분의 연구는 상층군락과 하층군락의 반사특성을 구분하지 않았다. 본 연구에서는 상층군락과 하층군락 식생의 생물계절학적 특성을 구분하여 탐지하기 위해 red, green, blue 그리고 near-infrared 의 네 가지 파장대를 가진 LED 센서를 이용하였다. LED 센서는 광릉 시험림 내의 활엽수림과 침엽수림 관측지에 서로 다른 네 군데의 높이에 설치되어 각 파장대의 반사도를 산출하였다. 또한 반사도를 이용하여 세 가지 식생지수(NDVI, EVI, Greenness index)를 산출하여 상층식생과 하층식생의 개엽기를 추정하였다.

• 중소기업융합학회논문지
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• 제6권4호
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• pp.99-106
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• 2016

본 논문에서는 White 색상을 달성하기 위한 R, G, B 혼합비율 Type을 기반으로 상대적으로 열화된 BER성능을 달성하는 파장 대역에 Forward Error Correction (FEC) 기법을 적용하여, 전체 시스템의 BER성능을 향상 시킬 수 있는 가시광 통신 시스템을 제안한다. FEC기법으로 Low Density Parity Check (LDPC) 코드를 적용하였으며, LDPC 부호는 Shannon의 한계치에 가장 근접하는 오류정정 부호로 평가되고 있으며, 오류마루(error floor) 현상이 나타나지 않고, 완전 병렬처리가 가능하여 고속 복호가 가능한 장점을 가지고 있다. 이와 같은 시스템에서 LDPC채널 코딩을 각 파장 대역에 부분적으로 적용함으로써, 주파수 효율 감소 및 데이터 전송률 감소를 완화 할 수 있다.

• 한국전기전자재료학회논문지
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• 제36권5호
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• pp.494-499
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• 2023

In this paper, in order to apply the CF (color filter) type of the micro light emitting device (Micro LED) display method, a study on the manufacturing process of red and green phosphor inks for the inkjet process was conducted. The blue light-emitting KSF and LuAG phosphors were respectively used to control the phosphor particle size to about 1㎛, and a phosphor ink was prepared by synthesizing with a low-viscosity solution (IPA/Eg). A chemical dispersion method was applied to selectively control the dispersion characteristics in the manufacture of phosphor inks, and in particular, phosphor inks with a dispersant applied a dispersant secured stable dispersion characteristic compared to phosphor inks without a dispersion process. Therefore, it seems possible to manufacture CF for Micro LED through an inkjet process capable of controlling the dispersion characteristics of phosphor ink.