• 수산해양기술연구
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• 제50권4호
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• pp.447-454
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• 2014

The marine microalgae Chaetoceros calcitrans was cultured under a fluorescent lamp (CON) and light-emitting diodes (LEDs) of various wavelengths (blue, LB; red, LR; green, LG; white, LW); changes in growth, fucoxanthin, chlorophyll-a, amino acid and fatty acid profiles were investigated. LR-exposed cultures exhibited the highest specific growth rate (SGR) (0.34), whereas LG-exposed cultures showed the lowest SGR (0.26). After cultivation for 10 days, the maximum dry cell weight (g/L) of LR-exposed cultures was significantly higher than that of those exposed to other light conditions (LR${\geq_-}$CON>LB${\geq_-}$LW${\geq_-}$LG). Eicosapentaenoic acid (EPA) levels were significantly higher in CON-exposed cultures compared to those exposed to LW (P<0.05), with no marked difference compared to those exposed to LB, LR and LG (P>0.05). The fucoxanthin content was highest in LB-exposed cultures ($6.3{\mu}g/mL$), whereas LW showed the lowest ($3.6{\mu}g/mL$; P<0.05). Chlorophyll-a content was highest in cultures exposed to LB compared to other light sources. These results suggest consistent differences in growth and biochemical composition after exposure to light of different wavelengths.

• 수산해양기술연구
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• 제51권4호
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• pp.475-483
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• 2015

The marine microalgae Isochrysis galbana was cultured under various light-emitting diode (LED) light conditions with different wavelengths to examine changes in growth and in amino acid and fatty acid profiles. The culture conditions for the microalgae were Conway medium, salinity of 33 psu, temperature of $24^{\circ}C$, and a 16/8 h light/dark photoperiod. Six light sources, including 5 units of 180W LED lamps (peak wavelength: blue [LB] 470 nm; green [LG] 525 nm; yellow [LY] 595 nm; red [LR] 636 nm; white [LW] 442 nm) and 1 unit of a 175W metal halide (MH) lamp, were used for the experiment. The dry cell weights ($gL^{-1}$) of I. galbana under different light conditions were in the order of LW>LB${\geq}$MH>LR>LG>LY. Levels of essential amino acids were revealed to be significantly higher under LW, LG, and MH than under the other wavelengths (P<0.05). The fatty acid, unsaturated fatty acid, and DHA contents of I. galbana were higher under MH, LW, and LG. In addition, the carotenoid content was higher under MH, LW, and LG than under the other wavelengths (P<0.05). The fucoxanthin content was highest under MH (0.28%) and lowest under LY (0.2%), and it was 0.26% under LW and LG. The results indicate that the combined use of LW and LG is effective when using LED lamps for I. galbana cultivation.

• 한국수산과학회지
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• 제46권3호
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• pp.259-265
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• 2013

The marine microalgae Nannochloropsis sp. was cultured under a metal halide lamp (MH) or light-emitting diodes (LEDs) of various wavelengths (blue, LB; red, LR; yellow, LY; green, LG; white, LW); changes in growth, total carotenoid, chlorophyll a, amino acid and fatty acid profiles were investigated. LB-exposed cultures exhibited the highest specific growth rate (SGR) (0.32), whereas LY-exposed cultures showed the lowest SGR (0.18). After cultivation for 9 days, the maximum dry cell weight (g/L) of LB-exposed cultures was significantly higher than that of those exposed to other light conditions (LB>MH>LW$${\geq_-}LG{\geq_-}$$LR>LY). The essential amino acid (EAA, %) contents of cultures exposed to LG, LB, LR and MH were higher than those exposed to LY and LW (P<0.05). Eicosapentaenoic acid and n-3 highly unsaturated fatty acid levels were significantly higher in MH-exposed cultures compared to those exposed to LY (P<0.05), with no marked difference compared to those exposed to LB, LG, LR and LW (P>0.05). The total carotenoid content was highest in LR-exposed cultures (18.0 mg/L), whereas MH showed the lowest (11.8 mg/L; P<0.05). Chlorophyll a content was highest in cultures exposed to LR compared to other light sources. These results suggest consistent differences in growth and biochemical composition after exposure to light of different wavelengths.

• 한국광학회지
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• 제32권5호
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• pp.235-243
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• 2021

Photobiomodulation (PBM) 치료법은 특정 파장대역의 광원이 미토콘드리아에서 ATP 생성을 촉진하는 현상을 이용하는 치료법으로서 상처 치유, 염증 감소, 통증 완화 효과가 있는 것으로 알려져 생물 및 의학 분야에서 많은 관심을 받고 있다. PBM 치료법에 대한 연구는 주로 레이저, 발광다이오드(LED)를 광원으로 사용하였고, 유기발광다이오드(OLED)가 가지는 장점에도 불구하고 PBM 치료법에 사용된 사례는 제한적이다. 본 연구에서는 적색(λ = 620 nm), 녹색(λ = 525 nm), 청색(λ = 455 nm) OLED 조명모듈을 사용하여 PBM에 의한 피부관리 효과를 분석하고 LED에 의한 PBM 효과와 비교하였다. OLED 조명모듈의 PBM에 의한 피부미용효과는 적색 OLED 조명모듈에 의한 collagen type 1 합성량 증가, 녹색 OLED 조명모듈에 의한 melanin 합성 억제, 청색 OLED 조명모듈에 의한 nitric oxide 생성 억제를 각각 측정하여 입증되었다.

• Nuclear Engineering and Technology
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• 제54권4호
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• pp.1288-1294
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• 2022

Hydrogen as an environmentally friendly energy carrier has received special attention to solving uncertainty about the presence of renewable energy and its dependence on time and weather conditions. This material can be prepared from different sources and in various ways. In previous studies, fossil fuels have been used in hydrogen production, but due to several limitations, especially the limitation of the access to this material in the not-too-distant future and the great problem of greenhouse gas emissions during hydrogen production methods. New methods based on renewable and green energy sources as energy drivers of hydrogen production have been considered. In these methods, water or biomass materials are used as the raw material for hydrogen production. In this article, after a brief review of different hydrogen production methods concerning the required raw material, these methods are examined and ranked from different aspects of economic, social, environmental, and energy and exergy analysis sustainability. In the following, the current position of hydrogen production is discussed. Finally, according to the introduced methods, their advantages, and disadvantages, solar electrolysis as a method of hydrogen production on a small scale and hydrogen production by thermochemical method on a large scale are introduced as the preferred methods.

• 한국유체기계학회 논문집
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• 제16권5호
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• pp.24-28
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• 2013

Visualization of internal flow of a regenerative blower has been made by injecting a tracer directly into the flow. For the convenience of visualization, working fluid has been replaced by water and marbling color oil has been used as a tracer. Oil droplet has been injected near the inlet of the blower and the streak has been recorded using a high speed camera with the illumination of high power light sources. At first, droplets have irregular motion in the near inlet area and enter into a groove of the impeller. Then the droplets circulate inside the groove while translated by the rotational motion of the impeller. When the droplets get out of the impeller groove, their speed is lower than that of impeller. And the droplets repeatedly enter into the groove and circulate inside the grooves. Then the droplets either flow to the outlet or reenter into the inlet area through stripper. Through this experimental study, internally circulating motion of the flow inside a regenerative blower has been characterized.

• 한국식품저장유통학회지
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• 제19권3호
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• pp.354-360
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• 2012

새송이 버섯 재배에 효과적인 LED 광질을 구명하기 위하여, 청색광(450 nm), 적색광(650 nm), 녹색광(525 nm), UV-A(365 nm) 및 혼합광(청$^*$적, 청$^*$녹, 적$^*$녹, 청$^*$적$^*$녹$^*$UV-A)의 LED광을 이용하여 재배한 새송이버섯의 품질특성을 조사하였으며, 대조구의 광원으로는 관행재배에 이용되고 있는 형광등을 사용하였다. LED의 파장이 길어질수록 총 길이가 길어지는 경향이었으며, 중량 또한 증가하는 것으로 나타났다. 또한, 섬유소, 단백질 및 무기질의 함량은 높고, 조지방의 함량은 매우 낮았으며, LED광을 이용하여 재배한 모든 구에서 조섬유 함량의 증가가 나타났다. 경도를 측정한 결과, 갓은 전반적으로 대조구와 유사한 조직감을 나타내었고, 자루는 적색광, 녹색광, 적 녹 혼합광 및 UV-A의 조건 하에서 재배한 새송이버섯이 유의적으로 낮은 것으로 나타났다. 한편, 적색광, 녹색광 및 적 녹 혼합광 처리구의 갓이 밝은 계통의 색으로 대조구의 갓 색과 유사하였고, 자루의 길이 역시 대조구와 비슷한 수준으로 생장하였다. 밝은 계통의 갓을 가진 구는 자루도 밝은 경향이었으며, 자루의 색도 측정 결과도 갓과 유사한 경향을 나타냈다. 관능평가 결과 외관이 대조구와 흡사할수록 높은 점수를 받았으며, 그 중 적색광 처리구가 선호경향이 가장 강한 것으로 나타났다. 반면, UV-A 및 청색광을 포함한 나머지 처리구는 어두운 계통의 갓으로 표고버섯 수준의 색을 띄었으며, 신장이 억제되어 짧은 자루를 가진 새송이버섯이 재배되었다. 또한, 이상의 결과로 광질은 새송이버섯의 품질에 큰 영향을 미치는 것을 알 수 있었으며, 새송이버섯 재배에 LED 기술을 접목시킬 때에는 적색광을 이용하는 것이 가장 적합한 것으로 판단된다.

• 융복합기술연구소 논문집
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• 제4권1호
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• pp.21-27
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• 2014

White LEDs (light-emitting diodes) are promising new-generation light sources which can replace conventional lamps due to their high reliability, low energy consumption and eco-friendly effects. This paper briefly reviews recent progress of oxy/nitride host phosphor and quantum dot materials with broad excitation band characteristics for phosphor-converted white LEDs. Among oxy/nitride host materials, $M_2Si_5N_8:Eu^{2+}$, $MAlSiN_3:Eu^{2+}$ M-SiON(M=Ca, Sr, Ba), ${\alpha}/{\beta}-SiAlON:Eu^{2+}$ are excellent phosphors for white LED using blue-emitting chip. They have very broad excitation bands in the range of 440-460 nm and exhibit emission from green to red. In this paper, In this review we focus on recent developments in the crystal structure, luminescence and applications of the oxy/nitride phosphors for white LEDs. In addition, the application prospects and current trends of research and development of quantum dot phosphors are also discussed.

• 한국생활과학회지
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• 제24권2호
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• pp.267-284
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• 2015

The purpose of this study is to extract the color chip from the works of Matisse with the exotic tastes, to analyze the characters of adjacent colors, and to suggest the color coordination of artistic character. The research method is based on the literature study which analyzes visual materials. The results are as follows. Considering the colors of Japanese taste, He employs vivid and strong tone in red, yellow, and blue, light tone in pink, purple, and green and deep tone in green, purple, blue and black. His color scheme is very bold and splendid. In his Algerian taste, red is very popular, but an attention should be paid in his development of orange and blue tones. In general, the usage of various tones brings colors into less relief and make the contrast of tones more conspicuous. His Spanish taste, based on red and orange, attracts attentions with strong impressions, but sometimes, dark or adjacent pale tones creates strong, mild and murky atmosphere. The Moroccan taste, based on the development of blue tones which have strong attraction implies the lightness but represents silent and calm. The Rumanian taste, represented in primary colors of red, yellow and blue and achromatic colors is bright and clear. In addition, its light tone in various colors represents peace and romance. The coordination of the exotic colors with the unique adjacent colors created by Matisse is not based on the established color coordination theory, but extracts colors in the aspect of culture borrowing. Therefore, it can double the effects of the color scheme expressed in the existing designs and be used as the global and multi-cultural design sources.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.79-79
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• 2022

Common Buckwheat is a crop with high nutritional value due to its high protein, magnesium, iron, and vitamin content, as well as excellent rutin and quercetin content. This study was conducted to investigate the main agricultural characteristics of common buckwheat genetic sources and use them as basic data for establishing cultivation technology and fostering new varieties. The seeds were planted in the research field of Chungbuk National University on 24th April, 2022 maintained at 15 × 20 cm planting spaces. To evaluate the genetic diversity and morphological traits of buckwheat, different kinds of qualitative and quantitative traits were investigated of the 50 varieties. The germination percentage of common buckwheat showed more than 85% that also showed the uniform germination. During the flowering period, all varieties bloomed within six days from June 18 to 23. The leaves color of common buckwheat were all dark green, and most of the stem colors were mixed with light green, light red, red, and crimson. The leaves of common buckwheat were mainly heart-shaped, and most of the flowers were white. The leaf length was 65.78 to 40.53 mm, and the width was 74.42 mm to 39.74 mm. The stem thickness was between 3.5 and 3.76 mm and the length was between 97.3 cm and 40.24 cm.