• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1623-1626
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• 2005

The thiogallate phosphors which are well known for a long time as phosphor materials for CRT or EL device were reported. Those have high luminescent properties at long-wavelength region. Among those phosphors, the samples with divalent europium doped CaGa2S4 were prepared by a simple process under the reduction atmosphere $(5%\;H_2/\;95%\;N_2)$ without toxic gas such as H2S or CS2. The prepared phosphor shows a higher luminescent efficiency (about 120%) than that of $YAG:Ce^{3+}$ phosphor. Consequently, this phosphor is possible to be applicable to white LED lamp because of the high luminescent efficiency.

• Asian-Australasian Journal of Animal Sciences
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• 제30권10호
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• pp.1396-1404
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• 2017

Objective: This study was determined the influence of virginiamycin supplementation on growth-performance and characteristics of digestion of cattle with decreasing dietary net energy value of the diet for maintenance ($NE_m$) from 2.22 to 2.10 Mcal/kg. Methods: Eighty crossbred beef steers ($298.2{\pm}6.3kg$) were used in a 152-d performance evaluation consisting of a 28-d adaptation period followed by a 124-d growing-finishing period. During the 124-d period steers were fed either a lesser energy dense (LED, $2.10Mcal/kg\;NE_m$) or higher energy dense (HED, $2.22Mcal/kg\;NE_m$) diet. Diets were fed with or without 28 mg/kg (dry matter [DM] basis) virginiamycin in a $2{\times}2$ factorial arrangement. Four Holstein steers ($170.4{\pm}5.6kg$) with cannulas in the rumen (3.8 cm internal diameter) and proximal duodenum were used in $4{\times}4$ Latin square experiment to study treatment effects on characteristics of digestion. Results: Neither diet energy density nor virginiamycin affected average daily gain (p>0.10). As expected, dry matter intake and gain efficiency were greater (p<0.01) for LED- than for HED-fed steers. Virginiamycin did not affect estimated net energy value of the LED diet. Virginiamycin increased estimated NE of the HED diet. During daylight hours when the temperature humidity index averaged $81.3{\pm}2.7$, virginiamycin decreased (p<0.05) ruminal temperature. Virginiamycin did not influence (p>0.10) ruminal or total tract digestion. Ruminal (p = 0.02) and total tract digestion (p<0.01) of organic matter, and digestible energy (p<0.01) were greater for HED vs LED. Ruminal microbial efficiency was lower (p<0.01) for HED vs LED diets. Conclusion: The positive effect of virginiamycin on growth performance of cattle is due to increased efficiency of energy utilization, as effects of virginiamycin on characteristics of digestion were not appreciable. Under conditions of high ambient temperature virginiamycin may reduce body temperature.

• Journal of Information Display
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• 제7권4호
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• pp.13-16
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• 2006

II-$III_{2}-(S,Se)_{4}$ structured of phosphor have been used at various fields because they have high luminescent efficiency and broad emission band. Among these phosphors, europium doped $BaGa_{2}S_{4}$ was prepared by solid-state method. We investigated the possibility of applying [ ] due to emissive property of UV region. Also, general sulfide phosphors were synthesized by using injurious $H_{2}S$ $CS_{2}$ gas. However, this study prepared $BaGa_{2}S_{4}:Eu^{2+}$ phosphor is addition to excess sulfur under 5% $H_{2}$/95% $N_{2}$ reduction atmosphere. So, this process could involved large scale synthesis because of non-harmfulness and simple process. The photo-luminescence efficiency of the prepared $BaGa_{2}S_{4}:Eu^{2+}$ phosphor increased by 20% compared with commercial $BaGa_{2}S_{4}:Eu^{2+}$ phosphor. From this, we could conclude that the prepared $BaGa_{2}S_{4}:Eu^{2+}$ could be applied to green phosphor for white LED of three wavelengths.

• 한국광물학회지
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• 제28권1호
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• pp.29-38
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• 2015

광석에서 순도 높은 금은을 추출하기 위해 사용된 청화법으로부터 시안이 유출되어 광석 내 존재하는 중금속들과 결합하여 다양한 형태의 시안화합물이 생성된다. 이러한 시안화합물은 난분해성 오염물질로서 인간을 포함한 생태계에 악영향을 끼친다. 결합력에 따라서 중금속과 결합한 시안화합물은 공유결합성 화합물(weak acid dissociable, WAD)과 착화합물(strong acid dissociable, SAD) 등으로 분류할 수 있다. 본 연구에서는 시안화합물의 존재 형태별 광촉매 산화 효율을 비교 평가하였다. 특히 자외선 LED 광원의 파장과 광촉매 표면 개질이 시안화합물의 분해에 미치는 영향을 살펴보았다. 실험 결과, 동일한 광촉매 산화 조건에서 자유 시안보다는 중금속과 결합한 시안화합물의 광산화 분해 효율이 떨어짐을 알 수 있었다. 그리고 자유 시안의 경우에는 짧은 파장에서 광촉매 산화가 효과적이었지만 중금속과 결합한 시안화합물의 경우에는 긴 파장에서 광산화 분해능이 더 높게 나타났다. 그리고 광촉매 표면 개질에 의하여 광촉매 산화 공정의 성능을 향상시킬 수 있음을 확인하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.471-472
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• 2007

We have demonstrated that the light extraction efficiency of GaN based light emitting diodes (LEDs) can be significantly enhanced by using photonic crystal and microcavity (PCMC) effects. It was found that the extraction efficiency of the PCMC-LEDs is 9.5 times larger than that of the normal LEDs.

• 국제초고층학회논문집
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• 제12권2호
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• pp.169-177
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• 2023

The massive increase in elevator usage and a severe demand for energy efficiency have prompted manufacturers to develop various innovative technologies, including AC and gearless motors, machine-room-less (MRL) technologies, regenerative drives, elevator ropes, and LED lighting. In addition, manufacturers are providing software solution systems such as destination dispatching systems, people flow solutions, standby mode, and predictive maintenance applications. Future technologies include electromagnetic levitation, circulating multi-car elevator systems, robotization, and drones. This article outlines elevators' technological advancements. It discusses how to harness new technologies and apply them to aging, modern, and future buildings.

• 한국환경과학회지
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• 제27권10호
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• pp.821-829
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• 2018

This study was conducted to examine the influence of Light-Emitting Diode (LED) light quality in urban agricultural plant factories on the growth and development of Seolhyang strawberry daughter plants in order to improve the efficiency of daughter plant growth and urban agriculture. LED light quality by demonstrated that above-ground growth and development were greatest for daughter plant 2. Daughter plant 1 showed the next highest growth and development, followed by daughter plant 3. Among the different qualities of LED light, the stem was thickest and growth rate of leaves was highest for R + B III (LED quality: red 660 nm + blue 450 nm/photosynthetic photon flux density (PPFD): $241-243{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) and lowest for R (red $660nm/115-117{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$). Plant height, leaf width, petiole length, and the leaf growth rate were highest for W (white fluorescent lamp/$241-243{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$) and lowest for R + B I (red 660nm+blue 450nm/$80-82{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$). For above-ground growth and development, as the plants surpassed the seedling age, mixed light (red + blue), rather than monochromatic light (red or blue), and higher PPFD values tended to increase development. Regarding the quality of the LED light, daughter plant 2 showed the highest chlorophyll content, followed by daughter plant 1, and daughter plant 3 showed the least chlorophyll content. When the wavelength was monochromatic, chlorophyll content increased, compared to that when PPFD values were increased. Mixed light vitality was highest in daughter plant 2, followed by 1, and 3, showed increased photosynthesis when PPFD values were high with mixed light, in contrast to the results observed for chlorophyll content.

• 한국전기전자재료학회논문지
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• 제32권1호
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• pp.86-92
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• 2019

Although perylene bisimide derivatives have advantages such as excellent thermal stability and high luminance efficiency, they have poor solubility characteristics in organic solvents. In this research, in order to improve the solubility characteristics, we prepared perylene bisimide derivatives (1C) and (2C) with swallow-tail substituted imide, which is known to lead to excellent solubility. The structures and properties of swallow-tail perylene bisimide (1C) and (2C) were analyzed by $^1H-NMR$, FT-IR, UV/Vis spectroscopy, and thermogravimetric analysis (TGA). The maximum absorption wavelengths of (1C) and (2C) in the UV/Vis spectrum were 558 nm and 556 nm, respectively, and the maximum emission wavelengths were 602 nm and 600 nm, respectively. In the TGA, (1C) demonstrated good thermal stability with less than 5 wt% weight loss up to $242^{\circ}C$. In the solubility test, (1C) and (2C) exhibited solubilities of more than 5 wt% in chloroform, ethyl acetate, and dimethylformamide, but not in methanol. When the compounds (1C) and (2C) were mixed with PMMA (polymethyl methacrylate), thin films showed peaks at 679 nm and 677 nm, respectively, in the photoluminescence spectra. (1C) was found to be a possible candidate as red organic phosphor for hybrid LEDs.

• 한국산학기술학회논문지
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• 제11권2호
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• pp.476-484
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• 2010

최근, 압전 변압기 기술의 급속한 발전으로 권선형 변압기를 대체할 수 있는 다양한 분야에 응용되고 있다. 압전 변압기는 자계의 잡음이 없고, 크기가 소형화되며 고효율과 고전력 밀도, 누설자속이 없어 노이즈 발생이 없고, 공진주파수만을 이용하므로 출력파형이 정현파에 가까워 고조파 잡음이 없는 등 권선형 변압기에 비해서 여러 가지 장점을 갖고 있다. 본 연구는 87.2[KHz]정도의 스위칭 모드에서 두께진동 모드 적층형 압전 변압기를 이용하여 전기적인 등가회로를 적용하여 DC-DC컨버터를 동작 하였다. 또한 DC-DC컨버터를 제안된 회로에 의해서 구동 고휘도 LED 구동 전원장치로써의 가능성을 제시 하였다.

• 한국산학기술학회논문지
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• 제16권10호
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• pp.6925-6931
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• 2015

LED(Light Emitting Diode)는 저 전력, 긴 수명, 고 휘도, 빠른 응답, 친환경적 특성으로 인해 조명, 디스플레이 등 여러 분야에 사용되고 있다. 백색광 발광다이오드 구현 방식에는 대표적으로 청색 LED 칩과 황색 형광체를 조합하여 백색광을 방출하는 유형이 사용 편리성, 경제성, 효율성 측면에서 LED 백라이트 유닛 및 LED 조명 제조에 가장 적합한 것으로 연구되어 실제 적용되고 있다. 백색광 구현 LED 칩 패키징 공정에서 청색 LED 칩에 황색 형광체에 실리콘을 혼합한 형광봉 지재를 토출하는 공정은 중요한 공정이다. 따라서 본 연구에서는 조명용 백색 LED 제조 공정에서 실리콘 봉지재를 토출하기 위하여 정전기력 방식과 보이스코일 모터를 이용하여 EHD 펌프 시스템을 개발하였다. 이를 위하여 인가전압 및 시간에 따른 유체곡면 형상을 확인하기 위하여 기초 토출 실험을 통해 최적의 토출 조건이 결정하였고 또한 검증을 위하여 실험계획법을 사용하였다. 검증된 토출 조건의 균일도를 확인하기 위하여 반복 토출 실험을 수행하였다.