• Journal of Plant Biology
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• 제39권4호
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• pp.279-286
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• 1996

To know the changes of rbcL mRNA level by illumination, Northern hybridization analysis was performed with maize (Zea mays L.cv. Golden X Bantam). The average level of rbcL. mRNA in the light-grown shoots was 3.1 times higher than that of the dark-grown shoots after 6 to 10 growth days. The maximum difference of rbcL mRNA level between the dark-grown and the light-grown shoots was 5.1 folds. These results indicate that accumulation of rbcL mRNAin maize shoots is induced by light. Since the transcriptional DNA binding proteins and their cognate promoter elements, we carried out gel-retardation assays to elucidate the specific binding proteins on the rbcL promoter. It was found that plastid proteins of light-grown shoots bound to the R2 DNA fragment (-33 to -229) and R3 DNA fragment (-230 to -418 from ATG) of the rbcL promoter. From the results of competitive binding assays and heat or protease treatments, it was demonstrated that the bindings were sequence-specific DNA-protein interactions. Therefore, it could be concluded that the rbcL promoter region has at least two specific recognition sites for plastid proteins.

• 대한의용생체공학회:의공학회지
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• 제14권1호
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• pp.81-88
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• 1993

This paper is the study of the reflectance of light from biological tissue for red and Infrared wavelengths and relates the acquired reflectance data to expected physiological changes within the skin and muscle layers associated with heat and exercise. The instrument was disigned to collect data from the calf muscle in human subjects with probe located at the surface of skin. Rapid data acquisition method allowed monitoring of rapid changes in reflecttance due to a stimulus. This study demonstrates that changes in O2 saturation and blood fractional volume expected within the dermis and muscle layers were asserted by examining the slopes of the plotted index for heat and exercise. The results presented in thls study support the claim that reflectance can separately discriminate between changes of blood volume and oxygenation in muscle and in skin. The data demonstrate the ability to measure consistent changes In tissue optical properties during exercise and heat.

• 한국정밀공학회지
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• 제29권7호
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• pp.778-784
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• 2012

In comparison with some other light sources, LED has merits such as increased life expectancy, fast response, pollution free, and high energy efficiency. Lately, due to development of LED with high brightness and capacity, LED has widely used in many industrial fields such as automotive, aviation, display, transportation and special lighting applications. Since the high heat generation of LED chips can cause a reduction in lifetime, degradation of luminous efficiency, and variation of color temperature, studies have been carried out on the optimization of LED packaging and heat sinks. In this study, experiments on measuring the heat generation rate of LED and the cooling performance of a heat sink were carried for analyzing the thermal characteristics of LED lighting system in free convection. From the results, dimensionless correlation on the cooling performance of heat sink in natural convection was proposed with Nusselt number and Rayleigh number as a guideline for designing cooling device of LED lightings.

• Design & Manufacturing
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• 제13권3호
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• pp.24-28
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• 2019

In this study, a study was carried out that could effectively produce a heat dissipation effect on plastic materials. Using carbon nanotube (CNT), aluminum powder and plastic, the material properties were tested in 2 cases of compounding ratio. The test sample mold was designed and constructed prior to the experiment. The experiments include tensile strength, elongation rate, flexural strength, flexural elasticity rate, eye-jaw impact strength, gravity and thermal conductivity. Results from 60% and 70% mixture of aluminium to plastic were tested, and a 10% less combined result was a relatively good property. For research purposes, the heat dissipation effect and light weighting obtained a good measure when the combined amount of Al was 60%.

• Design & Manufacturing
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• 제13권3호
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• pp.6-10
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• 2019

In this study, a study was carried out that could effectively produce a heat dissipation effect on plastic materials. Using carbon nanotube (CNT), aluminum powder and plastic, the material properties were tested in 2 cases of compounding ratio. The test sample mold was designed and constructed prior to the experiment. The experiments include tensile strength, elongation rate, flexural strength, flexural elasticity rate, eye-jaw impact strength, gravity and thermal conductivity. Results from 60% and 70% mixture of aluminium to plastic were tested, and a 10% less combined result was a relatively good property. For research purposes, the heat dissipation effect and light weighting obtained a good measure when the combined amount of Al was 60%.

• 조명전기설비학회논문지
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• 제22권12호
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• pp.1-9
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• 2008

이 논문에서는 100[W]급 Discrete LED 투광기 조명 제품 개발에 관한 것으로, 3[W] RGBA LED를 이용하여 광색 및 색온도 제어가 가능하도록 광학/방열/회로/시스템 설계를 통한 시제품을 제작하였다. 그 결과, 색온도 $2,000{\sim}10,000[K]$ 범위에서 흑체궤적에 정확히 일치하면서 연색지수가 $71{\sim}91$까지 고연색성을 실현하였으며, 동작전압 $90{\sim}250[Vac]$, 효율 87[%], 역률 93이상의 양호한 전기적 특성을 나타냈다. 또한 투광기의 협각/중각/광자 배광을 만족하기 위하여 LED 렌즈를 설계하였으며, 신뢰성 확보 및 주위온도에 따른 광출력 변화를 최소화할 수 있는 방열설계를 실시하였다.

• 한국환경과학회지
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• 제25권1호
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• pp.163-171
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• 2016

We analyzed the characteristics of fog formation in the Gumi Reservoir of Nakdong river with the field observation data for recent 2 years (1 April 2013~31 March 2015) collected by the national institute of meteorological research, KMA. In early morning, we frequently observe the steam rising from the water surface. The fog occurs from adding water vapor into the air. We call the fog as steam fog. Steam fogs occur when cold, dry air mixes with warm, moist air above a water surface. The steam fog appears mainly in autumn under the following conditions; (1) sensible heat is positive values ($10{\sim}20W/m^2$), (2) latent heat is more positive values ($25{\sim}35W/m^2$) than sensible heat, (3) cloudless nights with light winds (about 1.5 m/s), (4) under condition(3), mountainous winds easily blows into the reservoir.

• 한국의류학회지
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• 제23권3호
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• pp.483-494
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• 1999

This study investigated the relation between seasonal variation of clothing weight and its resting metabolic rate to determine the relation between proper living temperature and cold/heat tolerance. Thirty six subjects(18 males and females twenties) were composed to obtain the clothing weight(Total clothing weight) and resting metabolic rate for a year and grouped four seasons : spring (Mar-May) Summer(Jun-Aug) Fall(Sep-Nov) and Winter(Dec-Feb). The data of males and females were respectively divided into three groups by cluster analysis with clothing weight. 1. The resting metabolic rate of male(41.1kcal/m2/hr) was higher than that of female(33.2kcal/m2/hr). It is suggested there is gender difference in the resting metabolic rate(p<.001) 2. The resting metabolic rate of male and female was the highest in Winter. It is suggested there is seasonal variation in the resting metabolic rate(p<.001) 3. It was found that there was relation between clothing weight and resting metabolic rate. The difference of resting metabolic rate between Summer and Winter which is profitable to adaptation to living temperature was significant in light clothing weight in male as well as in female. 4. In comfortable sensation most subjects responded that he/she felt 'comfortable' except Winter. However the heavy clothing weight group felt 'a little uncomfortable' throughout all seasons. l In thermal sensation most subjects responded that he/she felt 'neutral' And then the heavy clothing weight group responded warmer in summer and cooler in winter than light clothing weight group. From the results it was confirmed that male and female showed seasonal variations in clothing weight and resting metabolic rate. Also the resting metabolic rate of male and female was influenced by the clothing weight. In short seasonal variation of resting metabolic rate was larger in light clothing weight group than in heavy clothing weight group. Therefore light clothing weight group is advantgeous in living temperature to improve cold/heat tolerance and it also shows that living with the light clothing weight may enhance the degree of adaptation to change of living environment

• Journal of Biosystems Engineering
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• 제26권5호
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• pp.441-448
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• 2001

Hot air heater with light oil combustion is used as the most common heater for greenhouse heating in the winter season. However, exhaust gas heat discharged to atmosphere through chimney reaches up to 10~20% of total heat capacity of the oil burred. In order to recover the heat of this exhaust gas and to use for greenhouse heating, the heat pipe type exhaust heat recovery system was manufactured and tested in this experiment. The system consisted of a heat exchanger made of heat pipes, ø15.88${\times}$600mm located in the rectangular box of 675(L)${\times}$425(W)${\times}$370(H)mm, an air suction fan and air ducts. The number of heat pipe was 60, calculated considering the heat exchange amount between exhaust gas and air and heat transfer capacity of a heat pipe. The working fluid of heat pipe was acetone because acetone is known for its excellent heat transfer capacity. The system was attached to the exhaust gas path. According to the performance test it could recover 53,809 to 74,613kJ/h depending on the inlet air temperature of 12 to -12˚at air flow rate of 1.100㎥/h. The temperature of the exhaust gas left the heat exchanger dropped to 100$^{\circ}C$ from 270$^{\circ}C$ after the heat exchange between the suction air and the exhaust gas.

• 한국전자통신학회논문지
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• 제10권5호
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• pp.615-622
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• 2015

반도체 제조기술의 발달로 고효율 및 고휘도의 LED가 개발됨에 따라 재래식 조명들로부터 LED를 이용한 조명으로 조명산업이 이동하는 추세이다. LED 조명등은 에너지 효율이 재래식 조명보다 뛰어나지만 많은 열이 발생한다는 단점이 있다. 특히 대형 LED 조명등에서는 이러한 발열문제가 심각한 실정으로, LED에 의한 메탈기판의 열은 납땜 부분을 열화시켜 조명등의 수명을 단축시키는 주된 원인이 된다. 따라서 대형 조명등을 개발하기 위해서는 이러한 열 문제를 해결하는 것이 매우 중요하다. 본 연구에서는 대형 LED 조명등에서 열문제를 해결하기 위한 방법을 제시하였고, 제시한 방식으로 1200W급 LED 조명등을 개발하였다. 본 연구에서 이용한 방법은 LED 조명등에 워터재킷을 설치하여 냉각수를 채웠으며, 소형의 수중펌프를 이용하여 냉각수를 순환시키는 방법을 이용하였다.