• Bulletin of the Korean Chemical Society
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• 제27권10호
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• pp.1549-1552
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• 2006

We report a new series of blue dopants composed of both electron donating and electron accepting moieties in one molecule, based on nalidixic acid. The EL device derived from the dopant exhibits pure blue light emission (0.15, 0.14) The current efficiency is estimated to be 3.88 cd/A at 100 $cd/m^2$, which shows remarkable enhancement, compared to that of the host itself (2.5 cd/A at 100 $cd/m^2$) under the same conditions. These results demonstrate that the incorporation of a proper guest into the host in a guest-host doped system improves not only the purity of the fluorescent blue emission but also elevates its quantum efficiency, thus improving the OLED performance.

• Restorative Dentistry and Endodontics
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• 제43권2호
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• pp.22.1-22.9
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• 2018

Objectives: To evaluate and compare light-transmittance in dental tissues and dental composite restorations using the incremental double-layer technique with varying layer thickness. Materials and Methods: B1-colored natural teeth slabs were compared to dental restoration build-ups with A2D and B1E-colored nanofilled, supra-nanofilled, microfilled, and microhybrid composites. The enamel layer varied from 0.3, 0.5, or 1.2 mm thick, and the dentin layer was varied to provide a standardized 3.7 mm overall sample thickness (n = 10). All increments were light-cured to $16J/cm^2$ with a multi-wave LED (Valo, Ultradent). Using a spectrophotometer, the samples were irradiated by an RGB laser beam. A voltmeter recorded the light output signal to calculate the light-transmittance through the specimens. The data were analyzed using 1-way analysis of variance followed by the post hoc Tukey's test (p = 0.05). Results: Mean light-transmittance observed at thicker final layers of enamel were significantly lower than those observed at thinner final layers. Within 1.2 mm final enamel resin layer (FERL) thickness, all composites were similar to the dental tissues, with exception of the nanofilled composite. However, within 0.5 mm FERL thickness, only the suprananofilled composite showed no difference from the dental tissues. Within 0.3 mm FERL thickness, none of the composites were similar to the dental tissues. Conclusions: The supra-nanofilled composite had the most similar light-transmittance pattern when compared to the natural teeth. However, for other composites, thicker FERL have a greater chance to match the light-transmittance of natural dental tissues.

• KIEAE Journal
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• 제5권2호
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• pp.35-41
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• 2005

This study was conducted to identify the effect of daylighting in hospitals on hospitalization time of patients and patients' outcomes in hospitals. Two major variations include orientation of hospital wards and the hospitalization times of various kinds of patients. Patients' data were obtained from two hospitals located in Seoul, Korea. The hospital buildings have north-facing and north-facing wards. The patients were classified according to the types of diseases and the orientation of the patient rooms. Then, statistical T-tests were applied in order to verify if natural light might shorter the hospitalization time of patients. The study also identified the types of diseases that were more responsive to the quantity of natural light in patient rooms. This information may be used as a basis for the development of guidelines for patient rooms in hospitals to achieve more effective healing environments. Likewise, the results may be applied to medical treatment buildings, recreational centers and hospital as well.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1381-1382
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• 2005

We report improved efficiency in blue electrophosphorescent organic light emitting diodes by introducing an interfacial exciton blocking layer between light emitting layer (EML) and hole transport layer (HTL). Iridium(III) bis [(4,6-di-fluorophenyl)- pyridinato -N,C2']picolinate (FIrpic) was used as blue phosphorescent dopant and JHK6-3 with carbazole and electron transporting group as host and also as the interfacial layer, resulting in drastic increase in quantum efficiency.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.51.2-51.2
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• 2010

In recently, interests in the New & Renewable Energy are increasing because of exhaustion of fossil energy and limit of greenhouse gas emission all over the world. Furthermore, improvements in living standards and high-raise Buildings due to the industrial growth require a lot of sunlight in the interior space. Sunlight system gets the natural light into the indoor dark space. There are a lot of type of systems which are reflector type, duct type, optical fibers type and so on. And these systems consist of light-collection module, light-transporting module and light-emitting module. In this research, we installed optical fiber sunlight system in our head office building and tested the system's performance and efficiency. Optical fiber sunlight system is closely connected with hour of sunlight, due to the system have to chase the sun for the solar concentrating, and the system's light-collection and light- transporting efficiency is important factors in the system's performance. As a result of the test, system can be used about 5.66 hours on average in a day, and it has a about 3.21 times collection efficiency and 5.5% transmission loss.

• 생명과학회지
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• 제29권10호
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• pp.1055-1061
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• 2019

식충식물(carnivorous plant)인 Sarracenia purpurea는 생육에 있어 매우 높은 수준의 광량을 필요로 하며 색, 과즙 등으로 벌레를 유인하여 영양분을 흡수하는 것으로 알려져 있다. S. purpurea는 약한 빛 조건에서 녹색을 띄었으며 강한 빛 조건에서는 잎을 포함한 포충낭 전체가 검붉은 색으로 변화하였다. 이와 같은 색의 변화는 질소비료를 첨가하였을 때에 관찰되지 않았다. S. purpurea를 붉게 물들이는 색소는 안토시아닌(anthocyanin)인 것으로 보고된 바가 있다. 본 연구에서는 빛의 세기와 질소 첨가에 따른 안토시아닌의 함량과 생합성 관련 유전자의 발현 특성을 분석하였다. $240{\mu}mol\;m^{-2}s^{-1}$의 강한 빛 조건에서의 안토시아닌 함량은 $40{\mu}mol\;m^{-2}s^{-1}$의 약한 빛에서 보다 6.15배 높았으며, 0.8% 요소 비료로 질소를 첨가하였을 때에는 약한 빛 조건과 큰 차이가 없었다. 안토시아닌의 초기 생합성 과정에 관여하는 CHALCONE SYNTHASE (CHS) 유전자는 강한 빛에서 발현이 증가하였고 질소 양분을 첨가하였을 때에 감소하였다. 이상의 결과는 빛과 토양의 환경 변화가 S. purpurea의 안토시아닌의 함량을 조절한다는 것을 보여주고 있다.

• 설비공학논문집
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• 제26권4호
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• pp.181-192
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• 2014

Light-shelf is one of the most efficient natural lighting systems due to the improved function of the inflow level of the outdoor natural light. However, the existing research on the light shelf limits to the rectangular parallelepiped space, so do not provide sufficient data for various shapes of spaces. Thus, this study aims at deriving proper plan and relationship of the light shelf through its performance assessment depending on the indoor space shapes and utilizing them as basic data of light shelf design. The conclusions are as follows : 1) for 6m space depth, standard intensity of illumination satisfaction depth has shown 8.3%~26.3% improvement through the adjustment of the angle and width when installing light shelf compared to no light shelf installation; 2) $-30^{\circ}$, $-20^{\circ}$ and $-10^{\circ}$ light shelves set by this study play only as a blind regardless of the shape of ceiling on the summer solstice, and it is unsuitable; and 3) this study has derived proper plan of light shelf upon space shapes based on energy reduction and indoor evenness. The study results provide expanded data of the performance assessment of the light shelves according to the different space shapes and light shelf factors, which serves as a basis of the light shelves designing.

• 한국유기농업학회지
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• 제27권2호
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• pp.161-171
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• 2019

A light-emitting diode (LED) is most efficient in terms of economic benefits. The aim of the present study was to evaluate the effects of LED lighting intensity on milk production, milk composition, and the immune response of Holstein cows. Thirty-eight lactating cows were assigned to four experimental groups: control group (exposed natural daylight without LED light) and three LED treatment group (50 lux; natural daylight and 6 h LED light of 50 lux intensity, 100 lux; natural daylight and 6 h LED light of 100 lux intensity, 200 lux; natural daylight and 6 h LED light of 200 lux intensity). There was a significant effect on the decrease ratio in milk production in 200 lux group. Lactose was significantly increased in 100 lux than the other LED treated groups. In addition to the hemolytic biochemical analysis, AST and β-HB were significantly increased in the 50 lux than the other groups. Prolactin and IGF-1 levels were significantly increased in 200 lux compared to other groups. Besides, cortisol was significantly higher in 50 lux and lowered in the 200 lux than the control, while IgA and IgG were not significant among the groups. Therefore, it was concluded that LED lighting intensity had some impact on blood parameters and immune responses in dairy cows with increased milk production.

• Animal cells and systems
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• 제12권2호
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• pp.69-75
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• 2008

The tumor suppressor and transcription factor p53 is a key modulator of cellular stress responses, and can trigger apoptosis in many cell types including neurons. In this study, we have shown that Microtubule-associated protein 1B(MAP1B) light chain interacts with tumor suppressor p53. MAP1B is one of the major cytoskeletal proteins in the developing nervous system and essential in forming axons during elongation. We also demonstrate that both p53 and MAP1B-LC1 interact in the nucleus in HEK 293 cells. Indeed, we show that the MAP1B-LC1 negatively regulates p53-dependent transcriptional activity of a reporter containing the p21 promoter. Consequently, MAP1B light chain binds with p53 and their interaction leads to the inhibition of doxorubicin-induced apoptosis in HEK 293 cells. Furthermore, these examinations might be taken into consideration when knock-down of MAP1B-LC1 is used as a cancer therapeutic strategy to enhance p53's apoptotic activity in chemotherapy.

• Architectural research
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• 제22권4호
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• pp.123-133
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• 2020

Light is an essential environmental element for elderly people to do various activities. At senior welfare centers, healthy indoor lighting is especially necessary because the facilities are used by the elderly to perform their mostly indoor activities. The purpose of this study is to evaluate light environments at senior welfare centers for well-being lighting characteristics. We based the study on the 'Biophilia' theory, a concept related to health from happiness. Thus, this study is mainly based on literary review and survey research. For this, we conducted a location focused field study to identify the current state of the lighting environments at senior welfare centers in Busan, South Korea. First, we constructed structural questionnaire to evaluate lighting environment based on 'Light and Space' biophilia theory. Then, to survey subjective evaluation, the participant of research included total of 122 senior welfare center users. Based on the results of this research, the conclusions are as follows; 1) overall, it seems that the overall result of the light environmental evaluation seems to be high because the evaluated facilities in the case survey in large-scale were recently built elderly welfare centers. 2) most of the healing design elements are focused on the introduction of natural light and psychological influence. The satisfaction with actual natural light is evaluated to be high. Although shadow and reflected light are very important in discrimination and recognition of indoor space and wayfinding, the evaluation of reflected light and shadow was low for the study. 3) items that are related to the functionality of the light were highly evaluated, while the items that are related to the spatiality of the light were rated poorly. This study has its significance when examining the effects of light environments within the welfare center form of the perspective of senior citizens. It can be referenced when reconsidering the recognition of light environment as a major consideration factor to establish a desirable senior welfare center environment.