• Title/Summary/Keyword: Light Intensity Distribution

Search Result 257, Processing Time 0.024 seconds

Acetone PLIF for Fuel Distribution Measurements in Liquid Phase LPG Injection Engine (LPG 액상분사 엔진에서 아세톤 PLIF를 이용한 연료분포 측정기법 연구)

  • 오승묵;박승재;허환일;강건용;배충식
    • Transactions of the Korean Society of Automotive Engineers
    • /
    • v.12 no.1
    • /
    • pp.74-82
    • /
    • 2004
  • Planar laser-induced fluorescence(PLIF) has been widely used to obtain two dimensional fuel distribution. Acetone PLIF is chosen because fluorescence signal from acetone as a fluorescent tracer is less sensitive to oxygen quenching than other dopants. Acetone PLIF is applied to measure quantitative air excess ratio distribution in an engine fueled with LPG. Acetone is excited by KrF excimer laser (248nm) and its fluorescence image is acquired by ICCD camera with a cut-off filter to suppress Mie scattering from the laser light. For the purpose of quantifying PLIF signal, an image processing method including the correction of laser sheet beam profile is suggested. Raw images are divided by each intensity of laser energy and profile of laser sheet beam. Inhomogeneous fluorescence images scaled with the reference data, which is taken by a calibration process, are converted to air excess ratio distribution. This investigation shows instantaneous quantitative measurement of planar air excess ratio distribution for gaseous fuel.

A Study on the Development of LED Spot Luminaire for Image Lighting (영상조명용 144[W] LED 스폿 등기구 개발에 관한연구)

  • Lee, Jang-Weon;Im, Jee-Weon
    • The Journal of the Institute of Internet, Broadcasting and Communication
    • /
    • v.10 no.5
    • /
    • pp.271-276
    • /
    • 2010
  • This study manufactured spot lighting fixtures for the broadcasting stage and LED lighting fixtures, measured the illumination, dimming, and color temperature, and installed LED lighting and spot Fresnel lighting to the camera by turns with the same subject to confirm and look into the possibility of replacement of LED lighting fixtures by shooting the figures and comparing them. The analysis of the photographed subject found that the lighting apparatus of LED 144[W] was superior to the tungsten halogen illuminator of 1 [kW] in terms of brightness and color of an image. The measuring of the energy used in 144 [W] LED lighting equipment and tungsten halogen 1[kW] lighting equipment suggested that LED saved more than 80 [%] of energy in the same intensity of illumination. The comparison of the light distribution and light intensity distribution of halogen tungsten illuminator of 1[kW] and LED 144[W] lighting apparatus found that when a subject received concentrated lighting, effective lighting is possible because the illumination intensity on the surface of the lighted subject was high. In performance halls or studios of about 6 [m] height, there is no problem of illumination intensity in LED 144 [W] illuminator. Therefore, it is possible to replace the existing tungsten halogen 1 [KW] illuminator one to one.

Growth Environments of Cypripedium macranthum Sw. Habitats in Korea (복주머니란 (Cypripedium macranthum Sw.)자생지의 생육환경에 관하여)

  • Kim, Jee-Yeon;Lee, Jong-Suk
    • Horticultural Science & Technology
    • /
    • v.16 no.1
    • /
    • pp.30-32
    • /
    • 1998
  • Growth environments of Cypripedium macranthum Sw. habitats distributed in mountains and highland plains of northern part of Kyunggi-do and Kangwon-do in Korea, were studied in order to obtain basic data. Mean temperature in habitats of Cypripedium macranthum was $14^{\circ}C$ and minimum value was recorded $-7^{\circ}C$ in January, and maximum value was $28^{\circ}C$ in August. Mean soil temperature of the orchid sites was $11^{\circ}C$ and minimum value was $-4^{\circ}C$ in January. The light intensity from March to May was 48,000~51,400 lux and the lowest value was 11,500 lux in July. Light intensity in shade habitat sites from July to August was dropped to 470~865 lux, and the SPAD value was 34.3 in July, which was the highest of the year. The range of soil acidity was pH 5.6~5.8 and soil moisture was 16.4%~36.2%. The highest soil moisture was 36.2% on June. The Cypripedium habitats were correlated with temperature (especially high temperature), light intensit, and soil moisture. However, critical factor seems to be soil moisture in distribution of Cypripedium macranthum in Korea.

  • PDF

Experimental Investigation of Horizontal Buoyant Discharges from a Rosette-type Riser Using LIF System

  • Kwon, Seok Jae;Seo, Il Won;Kim, Ho Jung
    • Proceedings of the Korea Water Resources Association Conference
    • /
    • 2004.05b
    • /
    • pp.463-467
    • /
    • 2004
  • Rosette-type diffusers with four-ports per riser are constructed in relatively shallow water in Korea. However, the trajectorial bending phenomena due to lower-pressure inside the surrounded buoyant jets on the riser was not considered in most models and was not observed without any experimental results. The buoyant jet behavior affected by the bending effect where there have been growing interests need to be verified experimentally and need to be preceded in the analysis of the characteristics of the buoyant jets oil a riser. The hydraulic model experiments have been carried out to investigate the characteristics of the behavior of horizontal buoyant jets discharged from a Rosette-type riser with four ports as well as single port over a certain range of the experimental conditions including initial momentum and initial buoyancy using LIF (Laser Induced Fluorescence) system to obtain concentration fields. The intensity of the fluorescent light in each pixel on the images obtained from LIF system with the tracer of Rhodamine H was converted to the local dye concentration with a set of calibration procedures to account for the non-uniform distribution of light intensity and the attenuation of light energy by water medium. The experimental results shows that the trajectories from Your ports tend to bend more and more to the inner side with the increase of the densimetric Froude number while the buoyant jet from a single port rises up without any bending phenomena. The previous models, VISJET and Seo et al. (2002), do not simulate the trajectories well except the region before the bending section. This study will focus on the analysis of the behavior of the buoyant jets for mainly a Rosette-type riser by conducting hydraulic model experiments using LIF system.

  • PDF

A Study on Performance Evaluation of Light Shelf according to the Reflectivity of Interior Space (실내 공간의 반사율에 따른 광선반 성능평가 연구)

  • Jeon, Gangmin;Lee, Heangwoo;Kim, Yongseong
    • Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
    • /
    • v.5 no.5
    • /
    • pp.461-470
    • /
    • 2015
  • There has been a significant increase in the amount of research on reducing the lighting power consumption of buildings and also an increasing demand for technological development. Light shelf has been recognized as one of the most efficient solutions to this issue and related researches have been conducted, which have mostly focused on factors related to simple light shelves and are not suitable as an appropriate basis for the design of light shelves. Thus this study aims to establish the proper design basis for light shelves by evaluating the performance of shelves per reflection rate in indoor areas. Power consumption rate and indoor illumination intensity distribution of a testbed built based on actual living conditions were calculated for the performance evaluation, of which the results are as following: 1) Reduction of reflection rate of ceiling and walls caused average illumination intensity in summer, winter and median seasons, and evenness per reflection rate of indoor areas was found to be different in summer, winter and median seasons, making it a necessary consideration for designing light shelves. 2) Calculation of power consumption from lighting control showed that a high reflection rate of indoor areas may be suitable for power consumption reduction, and that reflection rates higher than 80% for ceilings and higher than 75% for walls in terms of the efficiency of researches on the indoor reflection rate and its application would be appropriate. This study is meaningful as the research focuses on light shelves based on considering indoor environmental factors. More studies will be required that consider a variety of factors.

Habitat Characteristics and Distribution of Cymbidium kanran Native to Jejudo, Korea (제주한란의 자생환경 특성 및 분포에 관한 연구)

  • Lee, Jong Suk
    • Journal of the Korean Society of Environmental Restoration Technology
    • /
    • v.7 no.1
    • /
    • pp.40-49
    • /
    • 2004
  • This work carried out to define the characteristic of Cymbidium kanran habitat at Mt. Halla in Jejudo, Korea from the ecological point of view including geological and topographical features, air and soil temperature, relative humidity, fluctuations of light intensity, habitat vegetation, distribution altitude, area limit, and etc. And another goal of this study consider the conservation counterplan of the cymbidium habitat. Natural distribution areas of the cymbidium were observed more abundantly on the well drained south and east-facing slopes. Soil acidity was ranged from pH 4.1 to 5.3, and electric conductivity was ranged from 176.4 to 299.9 us/cm (average 215.3 us/cm). Base-saturation percentage of the habitat soil was below 50%, bulk density 0.42g/$cm^2$, particle density 2.05g/$cm^2$, humus content 26%, total nitrogen 0.82%, available phosphate 4.2 mg/kg, exchangeable potassium 0.63 Cmol/kg, calcium 0.44 Cmol/kg and magnesium 0.67 Cmol/kg. Annual mean air temperature was $15.4^{\circ}C$, however, air temperature was ranged $11.7{\sim}18.2^{\circ}C$ in spring, $21.2{\sim}23.8^{\circ}C$ in summer, $12.8{\sim}22.0^{\circ}C$ in fall and $5.5{\sim}7.8^{\circ}C$ in winter season. Annual mean soil temperature at depth of 10cm was $13.2^{\circ}C$ And minimum value was recorded $4.7^{\circ}C$ on January, and maximum value $22.5^{\circ}C$ on August. Relative humidity was ranged 90.8~94.7% in summer, 80.8~91.5% in fall and 77.6~84.2% in winter season. Minimum value was 56.5% on December, and maximum value was 100% on July and August. Light intensities were ranged from 400 to 1,800 lux at the greater part of Cymbidium kanran sites in Jejudo. Summer regarded as an lower light intensities was recorded to be range of 500~600 lux; however, autumn and winter were shown higher light regimes ranged from 3,500 to 3,800 lux. Therefore, one must be suprised that the cymbidium grow at the light condition of 6 lux (minimum) or 10,000 lux (maximum). Tree species keeping higher frequency rate and density were Eurya japonica, Camellia japonica, Castanopsis cuspidata, Carpinus laxiflora and Pinus densiflora. Number of trees growing in a 5${\times}$5m quardrat was 35 as an average, and proportion of evergreen versus deciduous was 5:1. Distribution altitude of the orchid habitat was ranged from 120m (low) to 840m (high) from sea level on the south facing slope of Mt. Halla, and was ranged eastern borderline of Gujwaup, Bukjejugun to western boundaries of Jungmundong, Seogwipo city. For the stable conservation of Cymbidium kanran habitat, sunlight regimes must be increased more by means of cutting trees or twigs in the site.

Optical Simulation Study on the Effect of Diffusing Substrate and Pillow Lenses on the Outcoupling Efficiency of Organic Light Emitting Diodes

  • Jeong, Su Seong;Ko, Jae-Hyeon
    • Journal of the Optical Society of Korea
    • /
    • v.17 no.3
    • /
    • pp.269-274
    • /
    • 2013
  • The effect of diffusing substrate and pillow lenses on the outcoupling efficiency of organic light-emitting diodes (OLEDs) was studied by optical simulation based on the point-dipole model. The diffusing substrate included Mie scatterers by which the condition of total internal reflection could be broken. The finite-difference time-domain method was used to obtain the intensity distribution on the transparent electrode of an OLED, which was used as a light source to carry out a ray-tracing simulation of the OLED and the diffusing substrate. It was found that the outcoupling efficiency of the OLED was sensitive to the thickness of organic layers and could be increased by 21.0% by adopting a diffusing substrate in which Mie scatterers whose radius was $2.0{\mu}m$ were included at the density of $10^7mm^{-3}$ and by 65.5% by forming one pillow lens with the radius of 2 mm on the front surface of the glass substrate. This study revealed that the outcoupling efficiency could be improved by adopting diffusing substrate and pillow lenses along with the optimization of the thickness of each layer in the OLED.

Verification on Diffusion of Beam Propagation in Randomly Distributed Scattering Medium (무질서하게 분포된 산란매질에서 빔전파의 확산에 관한 검증)

  • Kim, Ki-Jun;Lee, Hoo-Seol
    • Journal of the Korean Applied Science and Technology
    • /
    • v.24 no.4
    • /
    • pp.354-361
    • /
    • 2007
  • The distribution of light in a randomly scattering medium can represent problems found in many area. Particularly, in the clinical application of lasers for Photodynamic therapy(PDT) or in the fluorescence spectroscopy for biological tissue, turbidity plays a very important role. The influences of fluorophor, scatterer, and absorber in turbid material by light scattering were interpreted for the scattered fluorescence intensity and wavelength. The molecular properties have been studied by laser induced fluorescence spectroscopy in scattering medium as tissue. It has been found that the effects of optical properties in scattering media could be investigated by the optical $parameters({\mu}_s$, ${\mu}_a$ ,${\mu}t)$. Experimental and Monte Carlo simulation method for modelling light transport in tissue was applied. The experimental results using a randomly distributed scattering medium were discussed and compared with those obtained through Monte Carlo simulation. It'll be also important in designing the best model for oil chemistry, medicine and application of medical engineering.

Improve the Efficiency of Hybrid Solar LED Street Lamp Controller (하이브리드 태양광 LED 가로등 컨트롤러의 효율 개선)

  • Yun, Jung-Hyun;Kim, Jin-Sa
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.28 no.2
    • /
    • pp.131-136
    • /
    • 2015
  • We develop the 60 W class hybrid solar LED street lamp controller. The controller is providing power via an inverter in the day with the least solar cell and battery and charging the battery for the ESS, acts as a power failure, the built-in battery. Rated output of the fabricated LED street lamp is 300 W or greater battery capacity 300 Wh, discharge time 10 hr, LED street lamp efficiency showed a very high level of light efficiency by about 127 lm/W. In addition, as a result of light distribution pattern according to the distance and the light intensity measurement will be able to ensure a very high quality, show the constant brightness in the distance from the road lights 6 m is about 35~40 lux in uniformity ratio. The proposed hybrid solar LED street lamp system showed a high energy capacity of approximately 1.5 to 152.7% power generation efficiency than typical conventional solar street lamp.

Optical Characteristics of the LGP with Nanometer-patterned Sizes on Its Both Surfaces (복합 나노미터 패턴 도광판의 광특성)

  • Hong, Chin-Soo;Kim, Chang-Kyo;Lee, Byoung-Wook;Kim, Kyoung-Rae
    • Journal of Institute of Control, Robotics and Systems
    • /
    • v.14 no.6
    • /
    • pp.530-534
    • /
    • 2008
  • The LGP with nanometer structures resulted in enhancement of optical efficiency. Its fundamental mechanism is to recycle the polarized light via one round-trip through QWP(Quarter-wave Plate) but the maximum efficiency to reach with this method is limited up to 2. To get the larger efficiency than this a LGP with 1D PC(one-dimensional photonic crystal) nanometer-patterned on its top and bottom surfaces is suggested. For its optimum design the computer simulation is performed and suggests a grating that the spatial frequency between adjacent patterns is 500nm, its height 250nm, duty cycle 50%, and its cross section is rectangular. The angles of transmitted light are nearly the same as the results expected from the generalized Snell's law. Thus the Mathematica code, developed in this experiment, will be applied to designing the optimized LGP. The LGP with nanometer-patterened 1D PC LGP on its both surfaces shows the enhancement of transmitted intensity distribution up to 5.7 times.