• Title/Summary/Keyword: sunlight

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A Growth Responses of Indoor Ground Cover Plants according to a Light Source of Aritificial Light (인공광의 광원에 따른 실내 지피식물의 생육반응)

  • 방광자;박혜경;최경옥
    • Journal of the Korean Institute of Landscape Architecture
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    • v.27 no.5
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    • pp.114-119
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    • 2000
  • This study was carried out to obtain fundamental information of growth response of ground cover plants under artificial light quality at indoor. Aglaonema 'Silver Queen', Hedera helix L., Hoya carnosa 'Tricolor' and Saintpaulia ionantha 'Frances' were examined under a 400lux light intensity consisted of Mercury lamp, True-lite lamp, incandescent lamp, dark-room and sunlight indoor condition. A data analysis were performed by GLM, Duncan's multiple range test and mean score with SAS program. Results of experiments are as follows; 1. A plant growth status was better showed under the True-lite lamp than sunlight. 2. A Saintpaulia ionantha flower color was responded in the first place, the deep pinkish red color of Saintpaulia ionantha flower was obtained under Mercury lamp and "True-lite lamp", "sunlight", and incandescent lamp were follow. Flower numbers of Saintpaulia ionantha after 60 days tended to decrease under every artificial light quality. 3. Leaf length and leaf width were increased under True-lite lamp, but most of plants was not significantly affected by artificial light quality. 4. A stem length of Hedera helix was increased the highest rank under sunlight also, one of artificial light, the highest increase rank was showed under incandescent lamp. 5. Chlorophyll content was highly increased under Mercury lamp, but was responded poor under incandescent lamp.

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Effects of Differents types of Clothing and Colours on Clothing Microclimate in the Subjects wearing Sports Wear under Sunlight (일광하에서 운동시의 스포츠웨어 색상과 의복형태가 의복기후에 미치는 영향)

  • Kim, Tae-Kyu
    • Fashion & Textile Research Journal
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    • v.3 no.3
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    • pp.271-276
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    • 2001
  • In this study, We endeavored to revaluate the effects of different types of clothing and colors on clothing microclimate in the subjects wearing sports wear at sunlight environment. This study was conducted 4 different kinds (cotton 100%) of clothing ensembles, that was W-1(long trousers and shirt of white color), B-1 (long trousers and shirt of black color), W-s (short trousers and shirt white color), B-s (short trousers and shirt black color) and were done in a climate chamber under sunlight ambient temperature ($33.67{\pm}1.8^{\circ}C$, $46.0{\pm}8.5%RH$) by three males subject who are in good healthy. Start a 20-min rest period, 20-min bouts of exercise and final 20-min recovery period were performed. The kinetic load was given for 20 minutes under the condition of 6.0 km/hr walking speed on the treadmill. The results is as followed In case of same type of garment, temperature within clothing which is based on difference of color the white ensemble keeps higher temperature than black one. According to distribution chart of temperature within clothing in case of chest, white one shows higher temperature than black one, in case of back, black one shows higher temperature than white one. Difference of heart rate was so clear and sequence is W-1>B-1>W-s>B-s, so we could find same tendency with temperature within clothing.

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Enhance photoelectric efficiency of PV by optical-thermal management of nanofilm reflector

  • Liang, Huaxu;Wang, Baisheng;Su, Ronghua;Zhang, Ao;Wang, Fuqiang;Shuai, Yong
    • Advances in nano research
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    • v.13 no.5
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    • pp.475-485
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    • 2022
  • Crystalline silicon photovoltaic cells have advantages of zero pollution, large scale and high reliability. A major challenge is that sunlight wavelength with photon energy lower than semiconductor band gap is converted into heat and increase its temperature and reduce its conversion efficiency. Traditional cooling PV method is using water flowing below the modules to cool down PV temperature. In this paper, the idea is proposed to reduce the temperature of the module and improve the energy conversion efficiency of the module through the modulation of the solar spectrum. A spectrally selective nanofilm reflector located directly on the surface of PV is designed, which can reflect sunlight wavelength with low photon energy, and even enhance absorption of sunlight wavelength with high photon energy. The results indicate that nanofilm reflector can reduce spectral reflectivity integral from 9.0% to 6.93% in 400~1100 nm wavelength range, and improve spectral reflectivity integral from 23.1% to 78.34% in long wavelength range. The nanofilm reflector can reduce temperature of PV by 4.51℃ and relatively improved energy conversion efficiency of PV by 1.25% when solar irradiance is 1000 W/m2. Furthermore, the nanofilm reflector is insensitive in sunlight's angle and polarization state, and be suitable for high irradiance environment.

Color Changes of Natural-Dyed Fabrics under Sunlight (일광노출에 의한 천연염직물의 색상변화에 관한 연구)

  • Park Myung-Ja;Lee Youn-Hee;Yoon Yang-Noh
    • Journal of the Korea Fashion and Costume Design Association
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    • v.6 no.3
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    • pp.45-53
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    • 2004
  • Natural dyes have poor colorfastness as a result of the exposure of the dyed fabric to sunlight encountered during the display or wearing. As colors on fabrics fade excessively under sunlight, it is a problem to infer and restore the historic textiles with natural-dyed fabrics to original colors. The object of this study is to analyse the factors affected to color change under light. In experimental, fifteen natural dyes were dyed by the Korean traditional dyeing methods onto natural fiber fabrics: cotton, silk, ramie, and flex. Total 49 dyed fabrics in combination with dyes and fibers were used for the specimen. The Weather-O-meter was used for evaluating the effects of exposure to light for 2.5 to 450 hours. The process of color changes in the CIEL *A*B* color-order system to the exposure time were determined by spectrophotometer at 10$^{\circ}$ observer. Sunlight exposure caused significant changes in the color of natural-dyed fabrics. The degree and nature of color changes on the fabrics were dependent on the combination of fiber and the type of dye used. The groups of violet(Lithospermum erythrorhizon Sieb.et Zucc.) and black color(Ailanthus altissima Swingle, Phus trichocarpa Miq) yielded excellent colorfastness to light. The group of indigo blue color(Polygonum tinctorium Lour.) was also very resistant to fading in both exposure except silk. Whereas the dye groups of Red, Yellow, Orange, Brown colors indicated greatest changes in fading, particularly Carthamus tinctorius L.

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Optical Fiber Daylighting System Combined with LED Lighting and CPV based on Stepped Thickness Waveguide for Indoor Lighting

  • Vu, Ngoc Hai;Shin, Seoyong
    • Journal of the Optical Society of Korea
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    • v.20 no.4
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    • pp.488-499
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    • 2016
  • We present a design and optical simulation of a cost-effective hybrid daylighting/LED system composed of mixing sunlight and light-emitting diode (LED) illumination powered by renewable solar energy for indoor lighting. In this approach, the sunlight collected by the concentrator is split into visible and non-visible rays by a beam splitter. The proposed sunlight collector consists of a Fresnel lens array. The non-visible rays are absorbed by the solar photovoltaic devices to provide electrical power for the LEDs. The visible rays passing through the beam splitters are coupled to a stepped thickness waveguide (STW) by tilted mirrors and confined by total internal reflection (TIR). LEDs are integrated at the end of the STW to improve the lighting quality. LEDs’ light and sunlight are mixed in the waveguide and they are coupled into an optical fiber bundle for indoor illumination. An optical sensor and lighting control system are used to control the LED light flow to ensure that the total output flux for indoor lighting is a fixed value when the sunlight is inadequate. The daylighting capacity was modeled and simulated with a commercial ray tracing software (LighttoolsTM). Results show that the system can achieve 63.8% optical efficiency at geometrical concentration ratio of 630. A required accuracy of sun tracking system achieved more than ±0.5o . Therefore, our results provide an important breakthrough for the commercialization of large scale optical fiber daylighting systems that are faced with challenges related to high costs.

A Study on the Analysis of Residential Environment based on Object-oriented 3D CAD System (객체지향 3D캐드를 이용한 공동주택 환경(일조, 조망)분석에 관한 디지털적 분석방법 연구)

  • Ryu, Jeong-Won
    • Journal of The Korean Digital Architecture Interior Association
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    • v.5 no.2
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    • pp.9-14
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    • 2005
  • The analysis system has been needed to pre-evaluate and analyze the right for sunlight and the right for view in a residential environment since the urban high density and high rise residentinal building types have been prevailing these days. The purpose of this study is to propose an digital analysis method to evaluate sunlight and view conditions in a residential environment to improve the system performance in the sense of speed and accuracy. The digital analysis method using the object-oriented 3D CAD system and parametric library is studied and applied in the system and the various outputs of the analysis system makes possible to modify the design with the speed and accuracy as a result of the analysis. The study includes the evaluation for a daylight and view condition of each unit, and the interruption degree to a vicinity environment in terms of sunlight and view conditions comparing before and after construction.

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Analysis on the power generation efficiency by the direct sunlight (태양광 발전 시스템별 직사광선에 의한 발전효율 분석)

  • Lee, Jaydy;Rhee, Sang-Bong
    • Proceedings of the KIEE Conference
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    • 2008.11a
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    • pp.89-91
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    • 2008
  • The photovoltaic industry is growing at a tremendous speed. And it can be one of the key factors for success in the photovoltaic business to choose a suitable system, and setting it up right so as to get a maximum efficiency of the site. Therefore, it is regarded to be necessary to research the efficiency of systems to catch maximum photovoltaic energy. In this research, the expected power generation efficiencies are analysed, and compared with each other. This research considered the direct sunlight only, and the angle between the direction of solar panel and sunlight as factors to affect the power generation. Therefore, only rough analyses and estimations are found on 3 systems of fixed system, double-axes tracking system, and horizontal tracking system.

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Development of Aging Equipment and Testing Method for UV Effected Degradation Characteristics of Silicone Rubber (자외선 열화에 의한 실리콘고무의 열화 특성 연구를 위한 열화장치 및 시험방법의 개발)

  • Lee, Jeong-Heon
    • Proceedings of the KIEE Conference
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    • 2007.11c
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    • pp.93-96
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    • 2007
  • In this paper, the testing equipment for evaluating aging characteristics of outdoor silicone rubber insulator resulting from the environmental aging effect with regards to sunlight(UV) was developed. Influence of sunlight effect aging is seriously increase due to destruction of ozone layer which is occurred by consumption of fossil fuel. For this purpose, silicone rubber was aged under the artificial sunlight by exposure of xenon lamp radiation in the accelerating aging chamber and various test and analysis were performed such as breakdown strength, contact angle. And FT-IR analysis has been followed.

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LED array design for optimal combination of plant grown (식물재배를 위한 최적LED 배열조합설계)

  • Lee, Sungwon;Park, Sekwang
    • Journal of Plant Biotechnology
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    • v.41 no.3
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    • pp.123-126
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    • 2014
  • This paper is suitable for household plant factory by design and using both energy-saving LED and solar technology. Conventional household plant factory only depending on natural sunlight is sensitive for the change of external environment. Another a big problem of conventional common household plant factory is large power consumption. Recently interest in wellbeing food such as chemical-free is increased abruptly. To solve these two problems, this paper describes hybrid type of household plant. In particular, reducing the power photosynthesis photon flux density (PPFD) is kept uniform to enhance the growth of the plant. Ambient light sensor is adopted for the control of proper combination of sunlight and LED to keep PPFD constant.

SUN INCIDENCE ANGLE ANALYSIS OF KOMPSTAT-2 PAYLOAD DURING NORMAL MISSION OPERATIONS (정상 임무운용 상태에서 다목적실용위성 2호 탑재체에 대한 태양 입사각 분석)

  • 김응현;용기력;이상률
    • Journal of Astronomy and Space Sciences
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    • v.17 no.2
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    • pp.309-316
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    • 2000
  • KOMPSAT-2 will carry MSC(Multi-Spectral Camera) which provides 1m resolution panchromatic and 4m resolution multi-spectral images at the altitude of 685km sun-synchronous mission orbit. The mission operation of KOMSPAT-2 is to provide the earth observation using MSC with nadir pointing. KOMPSAT-2 will also have the capability of roll/pitch tilt maneuver using reaction wheel of satellite as required. In order to protect MSC from thermal distortion as well as direct sunlight, MSC shall be operated within the constraint of sun incidence angle. It is expected that the sunlight will not violate the constraint of sun incidence angle for normal mission operations without roll/pitch maneuver. However, during roll/pitch tilt operations, optical module of MSC may be damaged by the sunlight. This study analyzed sun incidence angle of payload using KOMPSAT-2 AOCS (Attitude and Orbit Control Subsystem) Design and Performance Analysis Soft ware for KOMPSAT-2 normal mission operations.

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