녹색광을 이용한 반사형 광용적맥파측정기의 주변광 간섭시 신호측정

장기영,고현철,이정직,윤영로,Chang, K.Y.,Ko, H.C.,Lee, J.J.,Yoon, Young Ro 대한의용생체공학회 2014 의공학회지 Vol.35 No.5

The purpose of this study is to verify the utility of reflected photoplethysmography sensor using two green light emitting diodes that influenced by ambient light. Recently it has been studied that green light emitting diode is suitable for light source of reflected photoplethysmography sensor at low temperature and high temperature. Another study showed that, green light is better for monitoring heart rate during motion than led light. However, it has a bad characteristic about ambient light noise. To verify the utility of reflected photoplethysmography sensor using green light emitting diode, this study measures the photoplethysmography signal that is distorted by ambient light and will propose a solution. This study has two parts of research method. One is measurement system that composed sensor and board. The sensor is made up PE-foam and Non-woven fabric for flexible sensor. The photoplethysmography signal is measured by measurement board that composed high-pass filter, low-pass filter and amplifier. Ambient light source is light bulb and white light emitting diode that has three steps brightness. Photoplethysmography signal is measured with lead II electrocardiography signal at the same time and it is measured at the finger and radial artery for 1 minute, 1000 Hz sampling rate. The lead II electrocardiography signal is a standard signal for heart rate and photoplethysmography signal that measured at the finger is a standard signal for waveform. The test is repeated 3 times using three sensor. The data is processed by MATLAB to verify the utility by comparing the correlation coefficient score and heart rate. The photoplethysmography sensor using two green light emitting diodes is shown better utility than using one green light emitting diode and red light emitting diode at the ambient light. The waveform and heart rate that measured by two green light emitting diodes are more identical than others. The amount of electricity used is less than red light emitting diode and error peak detectability factor is the lowest.

브라켓 접착시 광중합방식에 따른 전단결합강도와 파절양상 비교

신재호,임용규,이동렬 대한치과교정학회 2004 대한치과교정학회지 Vol.34 No.4

기존의 가시광선 중합기와 비교해서 plasma arc light와 LED 방식의 중합기를 이용해 브라켓을 치아표면에 접착한 후 탈락시키는 실험을 시행해 각각의 중합방식별로 전단결합강도와 접착파절양상을 비교함으로써 임상에서의 유용성을 평가하고자 하였다. 교정치료를 위해 발거한 상, 하악 소구치 60개를 윈통형의 레진블록에 매몰하여 시편을 제작하였다. 광중합형 접착레진인 Transbond XT를 이용하여 광중합 방식별로 조건(가시광선 중합기는 40초, LED방식의 중합기는 20초, 그리고 plasma arc light 방식의 중합기는 3초) 에 따라 브라켓을 접착한 후 만능물성실험기로 전단결합강도를 측정하고 브라켓 기저면을 광학현미경으로 관찰해 접착파절양상을 관찰하여 다음과 같은 결과를 얻었다. 1. 가시광선 중합방식과 LED 중합방식으로 중합시킨 군간에 전단결합강도의 유의성 있는 차이는 없지만 plasma arc Light 방식으로 중합시킨 군은 앞의 두 군에 비해 유의성이 있게 작은 값을 나타내었다(p>0.05). 2. 가시광선 중합방식으로 중합한 군과 LED 방식을 이용한 군에서는 파절양상이 거의 유사하게 나타났다. 두 군 모두 잔류접착제가 치아면에만 있는 경우가 제일 적은 비율을 보였으며 브라켓 기저면에 50% 이상의 접착제가 남아 있는 양상이 더 큰 비율을 보였다. 3. Plasma arc light 로 중합시킨 경우에는 접착제가 브라켓 기저면에 50% 이하로 남아있는 양상이 큰 비율로 나타났으며 잔류 접착제 전체가 치아면에 남아 있는 경우는 15%였다. 이상의 실험결과 plasma arc light를 이용한 중합 방식이 가시광선이나 LED 방식을 이용한 중합 방식에 비해 유의성 있게(p>0.05) 낮은 전단결합강도를 보였으나 세 방식 모두 임상적으로 사용하기에 충분한 전단결합강도를 보여 유용하게 사용할 수 있음을 알 수 있었다. The purpose of this study was to evaluate the clinical effectiveness of a plasma arc light and light emitting diode (LED), compared with shear bond strength and the failure pattern of brackets bonded with visible light in direct bonding. Brackets were bonded with Transbond XT to 60 human premolars embedded in the resin blocks according to different light-curing methods. Then, the shear bond strength of each group was measured using a universal testing machine (Instron) and the adhesive failure pattern after debonding was visually examined by light microscope. The results were as follows: 1. The shear bond strength showed no significant difference between the visible light and light emitting diode, but the plasma arc light exhibited a significantly lower shear bond strength compared with the visible light and light emitting diode. 2. In the visible light and light emitting diode, adhesive failure patterns were similar. Bond failure occurred more frequently at the enamel-adhesive interface. 3. The bonding failure of brackets bonded with plasma arc light occurred more frequently at the bracket-adhesive interface. The results of this study suggest that plasma arc light, light emitting diode and visible light are all clinically useful in the direct bonding of orthodontic brackets.

Visual Preference of Beet Armyworm to Light-Emitting Diodes

Hoi-Seon Lee 한국응용곤충학회 2012 한국응용곤충학회 학술대회논문집 Vol.2012 No.05

The aim of this study is to observe the attraction of four colored lights against beet armyworm (Spodoptera exigua). The visual preference of the beet armyworm for light-emitting diodes (LEDs) was examined by LED equipped phototactic chamber in the dark room at 27 ± 0.5°C and 60 ± 5% relative humidity. Evaluated specific wavelengths of LEDs were blue (470 ± 10 nm), green (520 ± 5 nm), yellow (590 ± 5 nm) and red (625 ± 10 nm), and compared with that of the commonly luring lamp used fluorescent (380-800 nm) which served as controls. The light intensity was tested at 20, 40, 60, 80 and 100 lx, and light-exposure time was determined at 20, 40, 60, 80 and 100 min. All of the light treatments with 40 lx intensity and the 60 min light-exposure time showed the highest attraction rate to S. exigua. Based on attraction rate of the green LED (88.9%) was the most attractive to S. exigua, followed by blue LED (81.1%), yellow LED (63.3%) and red LED (56.7%). In comparisons with LED and fluorescent light, the attractive rate to green LED against beet worm was more effective than that of fluorescent (80%) light. Overall, these results indicated that the eco-friendly LED could be a more effective substitute for the chemical free insect pest control system because of the various advantages.

05 포스터 발표 : 자연생태 환경 분야(PN) ; 식물공장 시스템내 광환경 제어가 적축면 상추 생장에 미치는 영향

허정욱 ( Jeong Wook Heo ),김동억 ( Dong Euk Kim ),이광재 ( Kwang Jae Lee ),강동현 ( Dong Hyeon Kang ),이시영 ( Si Young Lee ),신현만 ( Hyun Man Shin ),허윤선 ( Yoon Sun Huh ),이기열 ( Ki Yeol Lee ),김태중 ( Tae Jung Kim ),김숙종 ( 한국환경농학회 2014 한국환경농학회 학술대회집 Vol.2014 No.-

Plant factory, which considered as a novel plant production system preparing for the climate changes such as a global warming or raining, is an attractive year-round production technique of leafy plants regardless of place or season. The environmental factors of air temperature, relative humidity, nutrient, CO2 concentration, light intensity or quality inside the factory system influencing on growth have been reported. In this study, effects of light-environmental control of quality or intensity were investigated on growth of red curly lettuce ( Brassica rapa) seedlings with different four growth ages (0, 10, 20, and 30 days-old after transplanting) inside the factory system. ‘Tukksum’ red-curly lettuce which developed two true leaves was used as a plant material, and the seedlings were cultured under nutrient solution of 1.5 ds m-1 EC and 5.8 pH for 10 days after light exposure of 50, 100 or 230 μmol m-2 s-1. Light-emitting diodes of Red, blue plus red, and blue plus white were used, and fluorescent light was considered as a control. In 0 day-old seedlings after transplanting, dry weight and number of leaves under blue plus red light of 50 μmol m-2 s-1 light intensity for 10 days increased 28 and 19% comparing with the control, respectively. Increasing of fresh and dry weights in 30 days-old seedlings was significantly stimulated by blue plus red and red light. However, leaf pigmentation was inhibited by the red light regardless of the different growth ages and promoted by the mixture lights. Under 230 μmol m-2 s-1 light intensity, number of leaves, fresh and dry weights were greater by mixture-light exposure on 20 days-old seedlings. On 30 days-old seedlings, increment of dry and fresh weights was also affected by the mixture light. Leaf pigmentation was significantly inhibited by the red light regardless of the different light intensities in all the growth ages. Higher growth and pigmentation could be achieved at 20 and 30 days-old seedlings cultured under the mixture lights of blue, red, or white. It is concluded that light intensity should be controlled according to growth ages for growth and pigmentation, but rather stable control during culture period, and monochromic red is not suitable for leaf pigmentation of red curly lettuce in plant factory system.

수박 접목묘의 활착 특성에 미치는 청색, 적색, 및 원적색 발광다이오드의 영향

김용현,박현수 한국농업기계학회 2003 바이오시스템공학 Vol.28 No.2

This study was performed to investigated the effect of light quality on evapotranspiration and graft-taking characteristics of watermelon grafted seeding using blue, red and far-red light-emitting diodes(LED). At initial stage of graft-taking, blue light increased the evapotranspiration rate(EVTR) of grafted seedlings as compared to effects of red and far-red on EVTR of grafted seedlings. Grafted seedlings graft-taken under red and blue LED showed the high graft-taking of 100% and 96%, respectively. However, grafted seedlings graft-taken under far-red LED showed the graft-taking of 80% and survival of 60% with low seedlings quality after hardening. The stem of grafted seedlings graft-taken under red light was elongated but blue light suppressed the stem elongation. The leaf area of grafted seedlings graft-taken under red light was increased. It is concluded that the effect of light quality using LED on graft-taking of watermelon grafted seedlings was signficantly recognized. Considering the duration of quality of grafted seedlings graft-taken under artificial lighting, LED could be used as an effective lighting sources to validate the continuance of seedling quality.

Ultraviolet, blue, and green InGaN-based light-emitting diodes functionalized with ZnO nanorods

Jeong, Hyun,Salas-Montiel, Rafael,Lerondel, Gilles,Jeong, Mun Seok Elsevier 2017 JOURNAL OF ALLOYS AND COMPOUNDS Vol.708 No.-

<P><B>Abstract</B></P> <P>We investigated the augmentation in the light-output power of InGaN light-emitting diodes (LEDs) functionalized with ZnO nanorods (NRs) according to the emission wavelength of the LEDs and the volume fraction of the ZnO NRs. The ZnO NRs were fabricated on top of the ultraviolet, blue, and green InGaN LEDs using the hydrothermal method. The optical properties of the LEDs and ZnO NRs were examined by electroluminescence, photoluminescence, and Raman scattering at room temperature. The measurements of light-output power versus current and current as a function of voltage showed that there were considerably different enhancements in the light-output power of InGaN LEDs functionalized with ZnO NRs at different emission wavelengths of the LEDs, while no changes were observed in the electrical properties. Three-dimensional finite-difference time-domain simulations were conducted to support the experimental results. Both experimental and theoretical results indicated that the light-extraction efficiency of InGaN LEDs functionalized with ZnO NRs was significantly affected by the differences between the refractive indices of the GaN layers, indium–tin oxide layer, and ZnO NRs, which could be changed by the emission wavelength of the LEDs and volume fraction of the ZnO NRs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> ZnO nanorods are functionalized on surface of UV, blue, and green LEDs. </LI> <LI> Light output power of LED is augmented by ZnO nanorods due to light waveguide. </LI> <LI> Light extraction efficiency is notably influenced by emission wavelength of LED. </LI> <LI> Volume fraction of ZnO nanorods is significant for light extraction efficiency. </LI> </UL> </P>

Comparing the cytotoxic effect of light-emitting and organic light-emitting diodes based light therapy on human adipose-derived stem cells

김유진,김성원,이주로,엄숭호,정윤기,방석호 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.103 No.-

Light has attracted significant attention as a promising tool in the biomedical and cosmetic industries. However, little is known about the cytotoxic effects of conventional light sources based on their physicaleffects such as temperature and luminance. Here, the cytotoxic effects of representative light sources, alight-emitting diode (LED) and an organic light-emitting diode (OLED), were studied with humanadipose-derived stem cells (hADSCs). Regardless of the identical light energy conditions, LED groupinduced a higher apoptotic activity in hADSCs than the OLED group due to its significant heat generationcompared to OLED as further demonstrated with heat shock protein family gene expression. Additionally,we further confirmed the effect of luminance by irradiating light from LED and OLED under the sametemperature and energy conditions. Increased cell proliferation was confirmed in the OLED group, anda significant expression of intracellular reactive oxygen species was observed in the LED group withoutshowing heat shock protein upregulation. Taken together, the differences in cytotoxicity and cellularresponse after LED irradiation compared with OLED irradiation can be varied with temperature and luminancecontrol. This study suggests that OLED based device could be an alternative and promising lightsource for future biomedical and cosmetic applications.

Theoretical Analysis of the Light Extraction Efficiency of a Light-emitting Diode with a Bottom Photonic Crystal

Dang Hoang Long,In-Kag Hwang,Sang-Wan Ryu 한국물리학회 2009 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.55 No.1

A light-emitting diode (LED) with a bottom photonic crystal (PC), where the PC was fabricated below the active layer, was theoretically analyzed to obtain its light extraction efficiency. A finitedifference time-domain (FDTD) method was used for the simulation of LEDs with top and bottom PCs, and their light extraction efficiencies were compared. The bottom PC was shown to be effective in increasing the extraction efficiency for a small distance from the PC to the active layer. This superior extraction efficiency was attributed to the large confinement of light between the top surface of the LED and the PC. For the analyzed designs, we theoretically estimated the enhancement of light extraction for various lattice constants, PC thicknesses, ratios of the hole radius to the lattice constant, and distances from the PC to the active layer. The optimized parameters were obtained for the highest light extraction efficiency. A light-emitting diode (LED) with a bottom photonic crystal (PC), where the PC was fabricated below the active layer, was theoretically analyzed to obtain its light extraction efficiency. A finitedifference time-domain (FDTD) method was used for the simulation of LEDs with top and bottom PCs, and their light extraction efficiencies were compared. The bottom PC was shown to be effective in increasing the extraction efficiency for a small distance from the PC to the active layer. This superior extraction efficiency was attributed to the large confinement of light between the top surface of the LED and the PC. For the analyzed designs, we theoretically estimated the enhancement of light extraction for various lattice constants, PC thicknesses, ratios of the hole radius to the lattice constant, and distances from the PC to the active layer. The optimized parameters were obtained for the highest light extraction efficiency.

Effects of light-emitting diodes on protoplast regeneration from gametophytic cells of the commercial kelp Undaria pinnatifida (Laminariales, Phaeophyceae)

Avila-Peltroche, Jose,Won, Boo Yeon,Cho, Tae Oh The Korean Society of Phycology 2022 ALGAE Vol.37 No.2

Light-emitting-diodes (LEDs) are a lighting source useful for the precise evaluation of light quality effect on biological systems. Despite the importance of light spectra on the regeneration of land plant protoplasts ("naked cells"), this factor has not been tested yet on protoplasts from multicellular algae. This study reports on the effects of pure primary colors (red, blue, and green), dichromatic (red plus blue, RB, 1 : 2) and white LEDs on protoplast regeneration from male and female Undaria pinnatifida gametophytes. We also evaluated the effect of different light spectra on pigment composition (chlorophyll a, chlorophyll c, and fucoxanthine), and the light intensities under the best condition on the regeneration process. In the early stages, blue or RB LEDs increased the percentage of dividing female protoplasts, whereas red, blue, and RB LEDs enhanced that of dividing male protoplasts. In the later stages, RB LEDs showed a positive effect only on the percentage of multiple rhizoid-like protrusions (male gametophyte). They also increased the final area of both regenerated gametophytes. The LEDs did not affect pigment composition in female gametophytes. In male gametophytes, in contrast, they reduced chlorophyll c, while blue, RB, and green LEDs decreased fucoxanthin. Under RB LEDs, the optimal light intensity was 80 µmol photons m^-2 s^-1 for female gametophytes and 40 to 60 µmol photons m^-2 s^-1 for male gametophytes. Our results suggest that dichromatic LED illumination (red-blue) improves regeneration of U. pinnatifida gametophyte-isolated protoplasts. Thus, dichromatic LEDs might a suitable light source for enhancing protoplast regeneration in brown seaweeds.

발광다이오드(LED) 조명을 이용한 녹조 구멍갈파래U(lva pertusa)의 생장

권천중 ( Chun Jung Kwon ),최창근 ( Chang Geun Choi ) 한국수산과학회 2013 한국수산과학회지 Vol.46 No.5

To determine an efficient growth system for algal cultivation and to develop adequate culture system utilizing LED light, we investigated the effects of fluorescent and light emitting diode (LED) light source on the growth of Ulva pertusa . U . pertusa was cultured at 17 ºC under a light intensity of 35 μmol photons m-2s-1 and a 10L:14D photoperiod using either fluorescent or LED lamps. After 1 week of incubation under the same environmental condition, the length and width of Ulva pertusa grown under LED light were 1.5- and 1.9-fold greater, respectively,than the length and width of algae grown under fluorescent light. After two weeks, length and width were 2.6-and 2.0-fold greater, respectively, in algae grown under LED light. Total length and width of Ulva pertusa after three weeks of incubation were 1.7- and 1.2-fold greater in algae grown under LED light than those grown under fluorescent light. Therefore, the LED light induced significantly higher growth of Ulva pertusa than fluorescent light.