• Proceedings of the Plant Resources Society of Korea Conference
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• 2022.09a
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• pp.84-84
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• 2022

백리향(Thymus quinquecostatus)은 꿀풀과의 낙엽반관목으로 국내에서 자생하는 허브 식물 중 하나이다. 백리향은 특유의 좋은 향기 및 항산화, 항염증, 항균, 미백 등의 효능을 가지는 각종 폴리페놀 성분을 함유하고 있어 의약품이나 기능성 식품, 화장품의 천연 소재 원료로 활용되고 있다. 국내에서 백리향은 재배 환경에 맞추어 주로 고산지대의 노지에서 재배되고 있다. 노지 재배는 지역, 시기, 기후 등의 외부환경에 영향을 받아서 백리향의 유효성분, 품질 및 생산성을 안정적으로 유지하기 어렵다는 한계를 가지고 있다. 따라서 본 연구에서는 스마트팜 시스템을 활용하여 백리향의 유효 성분 등을 안정적으로 얻기 위한 생장조건을 탐색하기 위해 4종의 Light Emitting Diode(LED) 광원과 4종의 토양 조성에 따라서 백리향의 생육조건을 수행하였다. LED는 white, purple, RGB1, RGB2를 사용하였으며, 토양은 상토:펄라이트 비율(상토, 5:1, 3:1, 1:1)로 조성하여 백리향 묘목을 이식한 뒤 생장과 개화시기를 분석하였다. 재배환경은 백리향 재배지의 기상 데이터를 참고하여 동일하게 설정하였으며, 총 8주 동안 생육상태를 관찰하였다. 연구 결과 백리향 재배 4주차에 일부 개체에서 봉오리가 올라오며 개화를 시작하였으며, 8주차에는 대부분의 조건에서 개화를 관찰할 수 있었다. 백리향의 지상부 면적을 비교한 결과 가장 우수한 생장을 보이는 조건은 토양은 3(상토):1(펄라이트) 비율로 분석되었다. 따라서 이번 연구 결과를 바탕으로 백리향 재배에 스마트팜 농업 기술을 활용한다면 기존 노지 재배 한계를 보완하여 안정적이고 지속적인 백리향을 생산할 수 있을것으로 기대된다.

• ETRI Journal
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• v.46 no.2
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• pp.347-359
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• 2024

A simultaneous transfer and bonding (SITRAB) process using areal laser irradiation is introduced for high-yield and cost-effective production of mini- or micro-light-emitting diode (LED) display panels. SITRAB materials are special epoxy-based solvent-free pastes. Three types of pot life are studied to obtain a convenient SITRAB process: Room temperature pot life (RPL), stage pot life (SPL), and laser pot life (LPL). In this study, the RPL was found to be 1.2 times the starting viscosity at 25℃, and the SPL was defined as the time the solder can be wetted by the SITRAB paste at given stage temperatures of 80℃, 90℃, and 100℃. The LPL, on the other hand, was referred to as the number of areal laser irradiations for the tiling process for red, green, and blue LEDs at the given stage temperatures. The process windows of SPL and LPL were identified based on their critical time and conversion requirements for good solder wetting. The measured RPL and SPL at the stage temperature of 80℃ were 6 days and 8 h, respectively, and the LPL was more than six at these stage temperatures.

• Journal of Bio-Environment Control
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• v.28 no.2
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• pp.134-142
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• 2019

This study was conducted to evaluate the growth characteristics of lettuce (Lactuca sativa L.) as affected by artificial light sources and different growing media in a closed-type plant production system (CPPS). The lettuce seeds were sown in the 128-cell plug tray filled with 5 different growing media such as urethane sponge (US), rock-wool (RW), Q-plug (QP), TP-S2 (TP) and PU-7B (PU). The germination rate of lettuce seeds was examined during 12 days after sowing. On the 13 days after sowing, the lettuce seedlings were transplanted in a CPPS with temperature $25{\pm}1^{\circ}C$ and nutrient solution (EC $2.0dS{\cdot}m^{-1}$, pH 6.5) using recirculating deep floating technique system. The light sources were set with FL (fluorescent lamps) and combined RB LEDs (red : blue = 7 : 3) with $150{\pm}10{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD and a photoperiod of 14/10 hours (light/dark). The initial germination rate of lettuce was the highest in TP. The final germination and mean daily germination were the significantly highest in RW, QP and TP. The plant height, leaf length, leaf width, leaf area, and fresh and dry weights of shoot were the greatest in QP irradiated with RB LED. The number of leaves, fresh and dry weights of root and SPAD were the greatest in QP and TP irradiated with RB LED. The root length was the longest in TP irradiated with RB LED. Therefore, these results indicate that RB LED was effective for the growth of lettuce and it was also found that the QP and TP were effective for the germination and growth of lettuce in a CPPS. In addition, we confirmed the applicability of the newly developed growing medium TP for the lettuce production in a CPPS.

• Proceedings of the Safety Management and Science Conference
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• 2010.11a
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• pp.63-80
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• 2010

This paper describes the development of various lighting equipment adapting Ultra Constant Discharge Lamp that has newly been on commercial supply in the market. Meeting the required conditions of lighting equipment, various types of UCD Lamp equipment with excellent performances could be successfully developed. In order to provide a guideline for the economical lighting product selection, the analyzed data comparison between Hi-pressure Sodium Lamp which has been the most popular lamp for street lighting and UCD Lamp is provided. The conclusions of the study are made as follows; (1) The performance measurement result of UCD Lamp shows excellent Luminous Efficacy as 108Lm/W, daylight-like Color Rendering Index as 90Ra, and the best operating temperature range as $-50^{\circ}C{\sim}+85^{\circ}C$. Comparing to the Hi-pressure Sodium Lamp, UCD could be evaluated as much superior products. (2) In an assembled status with the lighting fixture (Type STB형-60W), UCD Lamp was tested OK for one hour duration at the temperature range form $-50^{\circ}C$ to $+85^{\circ}C$ and the humidity of 98%. The operation at the extremely low temperature can be an excellent feature to enable the export to the cold temperature regions such as Northern Europe and Russia and the specific applications for defense systems and special industry. (3) As UCD Lamp is a genuine Korea made product following Energy-saving and Eco-friendly policy, it should be appreciated as one of the best $CO^2$ reduction Green product.

• Korean Journal of Materials Research
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• v.18 no.11
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• pp.623-627
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• 2008

For possible applications as luminescent materials for white-light emission using UV-LEDs, $Ba_2Mg(PO_4)_2:Eu^{2+}$ phosphors were prepared by a solid state reaction. The photoluminescence properties of the phosphor were investigated under ultraviolet ray (UV) excitation. The prepared phosphor powders were characterized to from a single phase of a monoclinic crystalline structure by a powder X-ray diffraction analysis. In the photoluminescence spectra, the $Ba_2Mg(PO_4)_2:Eu^{2+}$ phosphor showed an intense emission band centered at the 584 nm wavelength due to the f-d transition of the $Eu^{2+}$ activator. The optimum concentration of $Eu^{2+}$ activator in the $Ba_2Mg(PO_4)_2$ host, indicating the maximum emission intensity under the excitation of a 395 nm wavelength, was 5 at%. In addition, it was confirmed that the $Eu^{2+}$ ions are substituted at both $Ba^{2+}$ sites in the $Ba_2Mg(PO_4)_2$ crystal. On the other hand, the critical distance of energy transfer between $Eu^{2+}$ ions in the $Ba_2Mg(PO_4)_2$ host was evaluated to be approximately 19.3 A. With increasing temperature, the emission intensity of the $Ba_2Mg(PO_4)_2$:Eu phosphor was considerably decreased and the central wavelength of the emission peak was shifted toward a short wavelength.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.1
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• pp.7-18
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• 2006

This study aims to analyze the illumination effects of bridges across the Han River. For the purpose, 8 bridges were selected. Field survey and measurements were performed, and the physical values such as luminance, color temperature and chromaticity were measured by Radiant Imaging Prometric 1400 Color. The results of the study are as follows; (1) Metal halide lamp, sodium lamp and LED(Light Emitting Diode) of various colors, are used in illuminating the bridges and create color contrasts and color changing by color filters. (2) Luminance contrast of the illuminated bridges affects 'modeling' and 'spare sense' of bridges, and it might improve people's preference and impression. (3) Color temperature of the illuminated bridges is influenced by 'color of bridge', 'material of bridge' and, 'color temperature and color of light sources'. (4) 'Structure of bridges' and 'luminaires' influence on the physical feature of the bridges. Especially, illumination of the bridges shows resemblant patterns by 'structure of bridges'.

• Journal of the Korea Safety Management & Science
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• v.12 no.4
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• pp.41-51
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• 2010

This paper describes the development of various lighting equipment adapting Ultra Constant Discharge Lamp that has newly been on commercial supply in the market. Meeting the required conditions of lighting equipment, various types of UCD Lamp equipment with excellent performances could be successfully developed. In order to provide a guideline for the economical lighting product selection, the analyzed data comparison between Hi-pressure Sodium Lamp which has been the most popular lamp for street lighting and UCD Lamp is provided. The conclusions of the study are made as follows; (1) The performance measurement result of UCD Lamp shows excellent Luminous Efficacy as 108Lm/W, daylight-like Color Rendering Index as 90Ra, and the best operating temperature range as $-50^{\circ}C{\sim}+85^{\circ}C$. Comparing to the Hi-pressure Sodium Lamp, UCD could be evaluated as much superior products. (2) In an assembled status with the lighting fixture (Type STB형-60W), UCD Lamp was tested OK for one hour duration at the temperature range form $-50^{\circ}C$ to $+85^{\circ}C$ and the humidity of 98%. The operation at the extremely low temperature can be an excellent feature to enable the export to the cold temperature regions such as Northern Europe and Russia and the specific applications for defense systems and special industry. (3) As UCD Lamp is a genuine Korea made product following Energy-saving and Eco-friendly policy, it should be appreciated as one of the best $CO^2$ reduction Green product.

• Journal of the Korean Vacuum Society
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• v.20 no.2
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• pp.127-134
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• 2011

We investigate the crystallographic orientation and strain states of the Ni/Ag ohmic contacts on p-type GaN. The Ag film in the Ni/Ag contact was severely agglomerated during high temperature annealing in air ambient. As a results, after annealing for 24 h, the Ni/Ag contact shows non-linear I-V curve and low light reflectance of ~21% at 460 nm wavelength. High-resolution X-ray diffraction results show that the interplanar spacing of Ag (111) planes is almost same to that of bilk Ag after annealing for 24 hrs, indicating that the in-plane tensile strain in the Ag film was fully relaxed due to the Ag agglomeration.

• Journal of Animal Science and Technology
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• v.63 no.3
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• pp.626-639
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• 2021

The purpose of this study was to determine the effects of photoperiod and light intensity on milk production, milk composition, hormones levels and blood metabolites indices of Korean Holstein dairy cows in automatic milking system (AMS). A total of 24 Holstein dairy cows were selected and used to four subsequent treatments for the experimental periods of 60 days. The light programs consisted of (1) Control: the natural photoperiod with 14.2 h of the light period and 9.4 h of the dark period (below 10 Lux); (2) T1: 16 h of the long day photoperiod (LDPP) with 50 Lux of light; (3) T2: 16 h of LDPP with 100 Lux of light; and (4) T3: 16 h of LDPP with 200 Lux of light, respectively. Importantly, there was a significant difference in the thurl activity of dairy cows between the different light intensity programs (p < 0.05). Milk yield was higher in T1 and T2 (40.80 ± 1.71 and 39.90 ± 2.02 kg/d, respectively) than those of Control and T3 (32.18 ± 1.51 and 35.76 ± 2.80 kg/d, respectively) (p < 0.05), but DMI was lower in T1, T2, and T3 compared to Control (p < 0.05). Also, milk fat percentage, the contents of milk fat and total solids were higher in T2 than those in the others (p < 0.05). The average daily melatonin level in milk was high to T3 (28.20 ± 0.43 pg/mL), T2 (24.62 ± 0.32 pg/mL), T1 (19.78 ± 0.35 pg/mL), and Control (19.36 ± 0.45 pg/mL) in order (p < 0.05). Also, the cortisol levels in milk and blood were lower in treatment groups than in Control (p < 0.05). The results of this study showed that it will be effective to improve the milk yield and milk composition, and to reduce the stress of dairy cows when the light conditions regulate to extend the photoperiod to 16 h at a light emitting diode (LED) intensity of 100 Lux under the AMS in dairy farm.

• Horticultural Science & Technology
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• v.35 no.2
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• pp.188-198
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• 2017

Asparagus (Asparagus officinalis L.) spears were treated with white (color temperature 4,500 k), blue (peak 450 nm), and red (peak 660 nm) light-emitting diodes (LEDs) at a photosynthetic photon flux density (PPFD) of $200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ for 12 h, and UV-B (280 nm) at 0.5 kJ or 1.0 kJ to determine the effect on agronomic characteristics, antioxidant phytochemicals, and antioxidant activity. The fresh weight, length, and width of spears were not affected by light quality treatments. The free sugars and chlorophyll contents were increased by 9 and 41%, respectively in the UV-0.5 kJ treatments. Among the antioxidant phytochemicals (vitamin C, total phenol, rutin, and total flavonoid), vitamin C was most greatly affected by the light treatments. Vitamin C content was significantly increased in asparagus spears subjected to the white (114%), red (137%), and UV-0.5 kJ(127%) treatments compared to the control. By contrast, rutin, total phenol, and total flavonoid content were increased only in samples subjected to the red and UV-0.5 kJ treatment. Furthermore, antioxidant activity, as measured by DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity, increased in white, red, and UV-0.5 kJ treatments by about 43, 41, and 43%, respectively, compared to the control. These results suggest that postharvest treatment of asparagus spears with red light at $200{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ for 12 h or with UV-B (280 nm) at 0.5 kJ could enhance the functional quality of the asparagus spears by increasing the content of phytochemicals like vitamin C, rutin, total phenolics, and total flavonoids.