• 한국기계가공학회지
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• 제19권4호
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• pp.30-35
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• 2020

The light guide plate (LGP) provides a surface light source on the back of the liquid crystal display (LCD), which is not self-emitting; thus, it is an essential component of display units requiring sufficient brightness. To maximize the light-emitting effect of an LGP, enough incident light, from the light source, should enter into its side. However, the current trend in LCD panels is represented by larger and thinner screens and this smaller thickness prevents the accordingly thin LGPs from providing sufficient brightness. This paper proposes a process for manufacturing wedge-type LGPs, which might increase the amount of incident light and, consequently the surface light emission, for applications in large LCDs. The proposed method was validated by building a dedicated manufacturing machine and performing illuminance experiments on the fabricated LGP.

• Journal of Acupuncture Research
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• 제32권3호
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• pp.211-220
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• 2015

Objectives : We report two cases of pressure ulcer patients to show the efficacy of treatment with acupuncture and Light Enitting Diode(LED) light therapy. Methods : We treated two pressure ulcer patients with acupuncture, LED light therapy, herbal medication and with a simple dressing. LED light with up to $4J/cm^2$ of energy irradiated the pressure ulcer site once a day for fifteen minutes. All patients received acupuncture treatment and simple dressing for wound care. We measured phase change of the pressure ulcer in terms of ulcer size, The National Pressure Ulcer Advisory Panel(NPUAP) stage and with the The Pressure Ulcer Scale for Healing(PUSH) tool(3.0). Results & Conclusions : In each of the two cases, pressure ulcer size and total score of the PUSH tool decreased and NPUAP stage was improved from II to I. This shows that acupuncture treatment and LED light therapy may have a considerable effect in healing on the pressure ulcer.

• KSBB Journal
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• 제28권3호
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• pp.170-176
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• 2013

The purpose of this study was to determine optimum condition of Pavlova lutheri and Phaeodactylum tricornutum. Detailed studies were carried out on the effects of various wavelengths of light-emitting diodes (LEDs), light intensities and air flow rations. For the Pa. lutheri, cell growth rates and maximum cell concentrations were similar regardless of wavelengths and air flow rates. Among the different light intensities, cell concentration increased when light intensity of red LED increased. For Ph. tricornutum, red LED was found to be the most effective light source, and light intensity of 3,100 Lux resulted in the most effective for the cultivation of Ph. tricornutum. Different air flow rates were tested to overcome shading effects due to denser cell concentration in the solution. Aeration of 0.8 vvm was determined to be the optimum aeration rate for the cultivation of Ph. tricornutum. Especially, five and two times greater cell concentrations of Pa. lutheri and Ph. tricornutum, respectively, were observed when air was applied.

• 대한임베디드공학회논문지
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• 제9권3호
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• pp.145-150
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• 2014

This paper presents an effective vision based method for LED traffic light detection at the daytime. First, the proposed method calculates horizontal coordinates to set region of interest (ROI) on input sequence images. Second, the proposed uses color segmentation method to extract region of green and red traffic light. Next, to classify traffic light and another noise, shape filter and haar-like feature value are used. Finally, temporal delay filter with weight is applied to remove blinking effect of LED traffic light, and state and weight of traffic light detection are used to classify types of traffic light. For simulations, the proposed method is implemented through Intel Core CPU with 2.80 GHz and 4 GB RAM, and tested on the urban and rural road video. Average detection rate of traffic light is 94.50 % and average recognition rate of traffic type is 90.24 %. Average computing time of the proposed method is 11 ms.

• 수산해양기술연구
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• 제53권3호
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• pp.240-245
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• 2017

In order to study for the growth of fish in the aquaculture industry, the behavior analysis of rock bream (Oplegnathus fasciatus) depending on the temperature and LED lights was conducted. In this study, water temperatures from 10 to 30 degrees were used. One red light (wave length: 622 nm; light power: 811 mW) and one green light (wave length: 518 nm; light power: 648 mW) were used. Behavior of the rock bream was analyzed at an average moving distance for one minutes (AMD) and a rate of movement. The mean AMD were respectively 5.3 m, 7.3 m and 3.0 m in the red LED light, green LED light and control condition. The mean rates of movement were 77%, 88% and 61% respectively in the red LED light, green LED light and control condition. The mean AMD during 24 hours were 3.1 m, 3.1 m and 3.3 m respectively in the red LED light, green LED light and control condition.

• 대한치과의사협회지
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• 제57권10호
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• pp.560-568
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• 2019

Purpose: This study evaluated the antibacterial effects of curcuma, ginger, and finger root extracts in water-soluble powder on planktonic Streptococcus mutans(S.mutans), which is known to cause dental caries, in order to confirm whether these extracts could perform as photosensitizers for the effects of photodynamic therapy (PDT). Methods: This study used the strain of streptococcus mutans ATCC 25175 distributed by the Korean Collection for Type Cultures of the Korea Research Institute of Bioscience & Biotechnology. Commercial edible curcuma, ginger and finger root were used as the natural extracts for the use of photosensitizer. To extract organic solvent, 3 g of each powder was mixed in $30m{\ell}$ of dimethyl sulfoxide (DMSO, VWR, Germany) before extraction. $1.8m{\ell}$ of the photosensitizer solution, manufactured in the concentrations of 5, 0.5, and $0.05mg/m{\ell}$, was mixed with $0.2m{\ell}$ of the S. mutans culture medium that had been cultured for 2 days. To induce the photodynamic reaction, Qraycam (AIOBIO, Seoul, Korea) equipped with 405 nm LED was used to expose light for 5 minutes to irradiate 59 nW energy for 300 seconds. Results: Compared with the case with no light, a higher photodynamic therapeutic effect was confirmed with $0.05mg/m{\ell}$ curcuma powder extract, the concentration of $0.5mg/m{\ell}$ and LED light of 405 nm wavelength (p=0.000, p=0.003). $0.05mg/m{\ell}$ of curcuma powder extract and the concentration of $0.5mg/m{\ell}$ showed 100% antibacterial effect when exposed to light, whereas the concentration of $5mg/m{\ell}$ showed 11.95% antibacterial effect. When exposed to light, $0.05mg/m{\ell}$ of ginger powder extract showed an antibacterial effect which didn't statistically decrease. The concentrations of $0.5mg/m{\ell}$ and $5mg/m{\ell}$ did not show any antibacterial effects. As a result of examining any photodynamic therapeutic effects of finger root powder extract on S. mutans, no statistically significant effect was found. Conclusion: The curcuma powder extract is expected to perform as a photosensitizer. Even though belonging to the same ginger family, ginger powder and finger root powder seem difficult to perform as photosensitizer.

• 한국융합학회논문지
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• 제10권12호
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• pp.177-181
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• 2019

본 연구는 광중합기의 청색광을 이용한 치과 치료과정에서 광중합기용 팁들과 보안경의 청색광 차단정도를 알아보기 위해, UV-Vis 스펙트로미터 기기에 광중합기용 팁들과 보안경들을 위치시키고 빛을 투과하여 측정한 결과를 비교 분석하였다. 분석결과, 분석에 사용한 4가지 종류의 광중합기용 팁들 모두 청색광 차단효과가 매우 우수한 것으로 나타났다. 보안경의 경우 붉은색 계열 보안경이 노란색 계열 보안경보다 광중합기용 팁들과 유사한 청색광 투과율을 보여 청색광 차단효과가 더 우수한 것으로 나타났다. 결과적으로 청색광 차단정도가 높은 광중합기용 팁 부착과 보안경 착용이 눈 보호를 위해 필요한 행위임을 추천한다. 이러한 행위는 눈에 대한 지속적인 자극과 피로감을 줄여줄 것이라 사료된다.

• 복식
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• 제14권
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• pp.133-144
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• 1990

The purpose of this study is to investigate the absorbance of the Shikonin, one of the major purple pigments, and the stability against the effect of light, $O_2$, and temperature. The effect of mordant and mordanting condition to color and color-fastness is compared and analysed through the color-fastness-test, color-difference value-test, and IR-test. The results were as follows; 1. The absorbance of Shikonin was examinated through 6 kinds of solutions and distilled water. Shikonin was absorbed by solutions rather easily than distilled water. 2. The light effect to Shikonin indicated that the solution with the light was more stable than that without it. 3. The effect of $O_2$ to Shikonin showed that the solution with the $O_2$ was more stable that without it $O_2$. 4. Shikonin -methyl alcohol solution was stable in $25^{\circ}C$. It was unstable in $60^{\circ}C$ and $100^{\circ}C$ with lowered absorbance and changed colors. 5. Color-fastness test to silk and cotton indicated washing color-fastness and perspiration color-fastness was more than 3 grade. But the light color-fastness and crocking color-fastness was low. 6. The comparison between non -colored sample and colored-sample showed the latter was better in fastness. 7. Mordant as $Alk(SO_4)_2{\cdot}24H_2O$ and $AlCl_3{\cdot}6H_2O$ was better than anything else in fastness. 8. Color-difference value-test indicated that the mordant which had the jade green color, the original purple pigment color, was the best in use. 9. The best way to extract the original purple pigment color was in $25^{\circ}C$, because extracted dyeing solution by Soxhlet had the bluish color.

• 대기
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• 제21권3호
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• pp.229-241
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• 2011

The continuous urbanizations by a rapid economic growth and a steady increase in population are expected to have a possible impact on meteorology in the downwind region. Long-term (1972~2007) trends of precipitation have been examined in the mid-Korean peninsula for the westerly condition only, along with the sensitivity simulations for a golden day (11 February 2009). During the long-term period, both precipitation amount (PA) and frequency (PF) in the downwind region (Chuncheon, Wonju, Hongcheon) of urban area significantly increased for the westerly and light precipitation ($PA{\leq}1mm\;d^{-1}$) cases, whereas PA and PF in the mountainous region (Daegwallyeong) decreased. The enhancement ratio of PA and PF for the downwind region vs. urban region remarkably increased, which implies a possible urbanization effect on downwind precipitation. In addition, the WRF simulation applied for one golden day demonstrates enhanced updraft and its associated convergence in the downwind area (about 60 km), leading to an increase in the cloud mixing ratio. The sensitivity experiments with the change in surface roughness demonstrates a slight increase in cloud water mixing ratio but a negligible effect on precipitation in the upwind region, whereas those with the change in heat source represents the distinctive convergence and its associated updraft in the downwind region but a decrease in liquid water, which may be attributable to the evaporation of cloud droplet by atmospheric heating induced by an increase in an anthropogenic heat. In spite of limitations in the observation-based analysis and one-day simulation, the current result could provide an evidence of the effect of urbanization on the light precipitation in the downwind region.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.387.2-387.2
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• 2016

Glass texturing is a sufficient method for changing the surface morphology to enhance the light trapping. In this study, glass texturing was applied to the perovskite solar cell for improving the current density. Glass substrates (back-side glass of FTO coated glass substrate) were textured by randomly structure assisted wet etching process using diluted HF solution at a constant concentration of etchants (HF:H2O=1:1). Then, the light trapping properties of suitable films were controlled over a wide range by varying the etching time (1, 2, 3, 4 and 5 min.). The surface texturing changed the reflected light in an angle that it can be reflected by substrate glass surface. As a result, Current density and cell efficiency were affected by light trapping layer using glass texturing method in perovskite solar cells.