• 한국세라믹학회지
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• 제52권4호
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• pp.229-233
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• 2015

Currently, the majority of commercial white LEDs are phosphor converted LEDs made of a blue-emitting chip and YAG yellow phosphor dispersed in organic silicone. However, silicone in high-power devices results in long-term performance problems such as reacting with water, color transition, and shrinkage by heat. Additionally, yellow phosphor is not applicable to warm white LEDs that require a low CCT and high CRI. To solve these problems, mixing of green phosphor, red phosphor and glass, which are stable in high temperatures, is common a production method for high-power warm white LEDs. In this study, we fabricated conversion lenses with LUAG green phosphor, SCASN red phosphor and low-softening point glass for high-power warm white LEDs. Conversion lenses can be well controlled through the phosphor content and heat treatment temperature. Therefore, when the green phosphor content was increased, the CRI and luminance efficiency gradually intensified. Moreover, using high heat treatment temperatures, the fabricated conversion lenses had a high CRI and low luminance efficiency. Thus, the fabricated conversion lenses with green and red phosphor below 90 wt% and 10 wt% with a sintering temperature of $500^{\circ}C$ had the best optical properties. The measured values for the CCT, CRI and luminance efficiency were 3200 K, 80, and 85 lm/w.

• 조명전기설비학회논문지
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• 제25권2호
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• pp.10-18
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• 2011

In order to develop highly-integrated RGBY(Red, Green, Blue, Yellow) LED light, a high thermal radiation ceramic package was manufactured, and the encapsulation process was applied with a vacuum printing encapsulation system(VPES). After the completion of vacuum printing, the shape of the encapsulation layer could be controlled by heat treatment during the curing process, and the optical power became highly increased as the encapsulation layer approached a dome shape. The optical characteristics involved in a Correlated Color Temperature(CCT), a Color Rendering Index (CRI), and the efficiency of RGBY LED light were able to be identified by the experimental designing method. Regarding the characteristics of the white light of RGBY LED light, which were measured on the basis of the aforementioned optical characteristics, CRI posted 88, CCT recorded 5,720[$^{\circ}K$], and efficiency exhibited 52[lm/W]. The chip temperature of RGBY LEDs was below 55[$^{\circ}C$] when the consumption power of LED chips was 0.1[W] for the red, 0.3[W] for the green, 0.08[W] for the blue, and 0.24[W] for the yellow. Also, the thermal resistance of the highly-integrated RGBY LED light measured by T3Ster was 2.3[K/W].

• 한국식품조리과학회지
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• 제14권4호
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• pp.380-387
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• 1998

The stability of red pepper seed oils during storage at 20${\pm}$3$^{\circ}C$, 40${\pm}$3$^{\circ}C$ and heating at 140${\pm}$3$^{\circ}C$ or 180${\pm}$3$^{\circ}C$ were measured to evaluate red pepper seed oil as a cooking oil. Two species of red pepper seeds (native, improved) were dried by either sunlight or heating to prepare the oil samples of NS (native, sunlight-dried), IS (improved, sunlight-dried), NF (native, heated), and IF (improved, heated). During storage at 20${\pm}$3$^{\circ}C$ or 40${\pm}$ 3$^{\circ}C$, acid values (AV) of all red pepper seed oils were higher than that of soy bean oil (SBO), however, peroxide values (POV) were similar to SBO. Antioxidative stability of NS was better than SBO but IF was not. By the heat treatments at 140${\pm}$3$^{\circ}C$ or 180${\pm}$3$^{\circ}C$, NS was identified to have better antioxidative stability than SBO and IF was the lowest. In sensory evaluation of each deep-fat fried potato-chip at 180${\pm}$5$^{\circ}C$, potato-chips fried in NS were better than that of SBO for color, taste, and flavor. NS-fried potato-chips got the highest score in overall acceptance (p<0.05), however, those of IF showed little acceptance. When blended oils (SBO: NOS, 0, 25, 50, 75%) were used, 50% blended oil was the best for taste, color, flavor, cripness, and total acceptance.

• 한국세라믹학회지
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• 제50권6호
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• pp.454-459
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• 2013

Recently, remote phosphors have been reported for application to white LEDs to provide enhanced phosphor efficiency compared with conventional phosphor-based white LEDs. In this study, a remote phosphor was produced by coating via screen printing on a glass substrate with different numbers of phosphor coating. The paste consists of phosphor, lowest softening glass frits, and organic binders. The remote phosphor could be well controlled by varying the phosphor content rated paste. After mounting the remote phosphor on top of a blue LED chip, CCT, CRI, and luminance efficiency were measured and values of 5300 K, 62, and 117 lm/W were respectively obtained in the 80 wt% phosphor with 3 coating layers sintered at $800^{\circ}C$.

• 조명전기설비학회논문지
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• 제23권12호
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• pp.23-30
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• 2009

LED조명장치는 자동차분야, 항공, 디스플레이, 전송장치 그리고 특수조명등의 응용장치로의 활용이 증가하고 있다. 일반적으로 고출력 RGB 멀티칩 LED는 표시용이나 경관조명용 또는 감성조명용으로 적용되고 백색 LED는 표시용 조명에서 최근 들어 일반조명용으로 적용되고 있으며, 고출력 백색 LED의 출시와 광효율의 증가는 이를 더욱 가속화하고 있다. 본 논문에서는 백색 LED와 RGB 멀티칩 LED 조명장치를 동일한 사양으로 제작하여 물리적, 전기적, 광학적 조명특성을 분석하여 향후 LED조명시스템의 제작에 정량적 데이터를 제공하고자 한다. 이를 위해 LED의 주요한 물리적 특성인 방열특성에 대한 성능분석, 전기적 특성의 분석을 위한 전력 및 드라이브 효율에 대한 성능분석을 수행하였고 조명특성을 위한 연색성, 배광특성, 광효율을 측정하였다. 백색 LED와 RGB 멀티칩 LED 조명장치를 활용한 응용장치의 적용방법을 확립하고 나아가 다양한 조명시스템에 LED 조명장치를 적용하는데 참고가 되는 기초 데이터를 제시하고자 한다.

• 한국멀티미디어학회논문지
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• 제8권12호
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• pp.1649-1657
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• 2005

In this paper, a fast implementation of JPEG is discussed and its application to multimedia service is presented for mobile wireless internet. A fast JPEG player is developed based on several fast algorithms for mobile handset. In the color transformation, RCT is adopted instead of ICT for JPEG source. For the most time-consuming DCT part, the binDCT can reduce the decoding time. In upsampling and RGB conversion, the transformation from YCbCr to RGB 16 bit is made at one time. In some parts, assembly language is applied for high-speed. Also, an implementation of multimedia in mobile handset is described using MJPEG (Motion JPEG) and QCELP(Qualcomm Code Excited Linear Prediction Coding). MJPEG and QCELP are used for video and sound, which are synchronized in handset. For the play of MJPEG, the decoder is implemented as a S/W upon the MSM 5500 baseband chip using the fast JPEG decoder. For the play of QCELP, the embedded QCELP player in handset is used. The implemented multimedia player has a fast speed preserving the image quality.

• 대한기계학회논문집A
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• 제28권1호
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• pp.63-69
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• 2004

It is of great interest to enhance mixing performance in a microchannel in which the flow is usually characterized as a low Reynolds number (Re) so that good mixing is quite difficult to be achieved in this laminar flow regime. In this regard, we present a new chaotic passive micromixer, named Barrier Embedded Micromixer (BEM), of which the mixing mechanism is based on chaotic flows. In BEM, chaotic flow is induced by periodic perturbation of the velocity field due to periodically inserted barriers along the channel wall while a helical type of flow is obtained by slanted grooves on the bottom surface of the channel in the pressure driven flow. To experimentally compare the mixing performance, a T-microchannel and a microchannel with only slanted grooves were also fabricated. All microchannels were made of PDMS (Polydimethylsiloxane) from SU-8 masters that were fabricated by conventional photolithography. Mixing performance was experimentally characterized with respect to an average mixing intensity by means of color change of phenolphthalein as pH indicator. It was found that mixing efficiency decreases as Re increases for all three micromixers. Experimental results obviously indicate that BEM has better mixing performance than the other two. Chaotic mixing mechanism, suggested in this study, can be easily applied to integrated microfluidic systems , such as Micro-Total-Analysis-System, Lab-on-a-chip and so on.

• 대한기계학회논문집A
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• 제29권6호
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• pp.904-912
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• 2005

The flow in a microchannel is usually characterized as a low Reynolds number (Re) so that good mixing is quite difficult to be achieved. In this regard, we developed a novel chaotic micromixer, named Barrier Embedded Kenics Micromixer (BEKM). In the BEKM, the higher level of chaotic mixing can be achieved by combining two general chaotic mixing mechanisms: (i) splitting/reorientation by helical elements inside the microchannel and (ii) stretching/folding via periodically located barriers on the channel wall. The fully three-dimensional geometry of BEKM was realized by a micro-stereolithography technology, in this study, along with a Kenics micromixer and a circular T-pipe. Mixing performances of three micromixers were experimentally characterized in terms of an average mixing color intensity of phenolphthalein. Experimental results show that BEKM has better mixing performance than other two micromixers. Chaotic mixing mechanism, proposed in this study, could be integrated as a mixing component with Micro-Total-Analysis-System, Lab-on-a-chip and so on.

• 복식문화연구
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• 제18권2호
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• pp.348-370
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• 2010

The purpose of this study was to propose some plan which could satisfy consumer's expectation emotional needs by comparing emotional scale between fashion brand image and brand website coloration image. For this study, 12 brand websites within four fashion zone, men's clothing, women's clothing, casual wear, and sports wear were chosen. The questionnaires were comprised of 27 emotional adjectives which were selected from previous studies. The questionnaires were distributed to university students and office workers for 3 to 17 on September. Among them, 118 questionnaires were analyzed by SPSS tool. The qualitative analysis for emotional adjective sorting, content analysis for website color chip sorting, and quantitative analysis for consumers were used in this study. Some differences exist between brand image and website coloration band image as the result. As the numbers of internet user became larger, the costumer's emotional image which gives maximum satisfaction is getting more important in fashion brand website. Therefore, fashion website managers should satisfy consumers with functional and emotional needs.

• 조명전기설비학회논문지
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• 제19권2호
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• pp.1-6
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• 2005

본 연구에서는 광고 조명으로 인한 에너지 소비를 극소화하기 위하여 OF-LED(Optical-Fiber LED)를 이용한 에너지 절약형 광고 조명 시스템에 대하여 연구하였다. 제안한 OF-LED광고 조명 시스템은 에너지 소비가 획기적으로 저감되고 시스템의 소형화가 가능하며, 부조일이 높은 장마철을 제외하고는 태양광 발전만으로 운영하는 큰 장점을 가진다. 태양전지의 출력 특성에 의한 배터리의 최단$\cdot$최적 충전을 위해 정전류$\cdot$정전압 제어법(CCVC)과, IncCond알고리즘을 병행하여 적용하였다 그리고 원칩 마이크로프로세서로 디스플레이 제어와 충 방전제어를 동시에 수행하도록 하였다. 이를 실험을 통하여 제시된 시스템의 유용성을 입증하였다.