• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.54-58
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• 2001

The measurement method of the spectral emissivity by using hemispherical mirror which has an inclined observation hole is studied. This method is useful in measuring the spectral emissivity of the solid material both conductor and non-conductor. In this study, the effective reflectivity of the hemispherical mirror is also measured for calculating the spectral emissivity of materials. The effective reflectivity measured is 0.9.

• 한국태양에너지학회 논문집
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• 제30권5호
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• pp.100-106
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• 2010

The purpose of this study is to predict the effective sky temperature on Osan City during the summer. The north latitude, east longitude of Osan City is $37^{\circ}06'$ and $127^{\circ}02'$. The altitude from the sea level is 48m. Empirical relations of the effective sky temperature suggested by Duffie and Beckman are compared on clear days. For the effective sky temperature prediction, data measured by the Korea Meteorological Administration is used as an input to the Bliss model. Both Hottel and Krondratyev model are used to calculate the water vapor emissivity. The results using Hottel's model match well with the empirical relation proposed by Bliss. The results show maximum, minimum, and average values depending on water vapor emissivity model. The maximum deviation is about 10K and is due to total emissivity model.

• 대한기계학회논문집B
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• 제27권6호
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• pp.789-795
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• 2003

It is studied that the measuring method of the spectral emissivity by using hemispherical mirror with an inclined observation hole. The in-service calibration method of mirror reflectivity is also dealed with. It is possible to apply this method on measuring emissivity of conductor or non-conductor.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.337-340
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• 2007

Many researches conducted to investigate the relationship between surface emissivity and surface temperature in the past two decades and pointed out that the emissivity play a key role in applying remote sensing data to retrieve surface temperature. The task of surface temperature estimation is so important in many research fields, such as earth energy budgets, evapotranspiration, drought, global change and heat island effect. Therefore, it is indispensable to develop an effective and accurate technique to estimate the emissivity for accurate surface temperature estimations. This study developed an improved emissivity estimation technique for the use of surface temperature retrievals with MODIS data. The result of applying this improved technique using Band 31 of MODIS shows that the accuracy of estimated surface temperatures will be improved. This study also uses MODIS data observed in 2005 to establish the relationship between the surface emissivity correction factor and NDVI. Through the use of these correction factors, the land surface temperature can be retrieved more accurate with MODIS data.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2044-2049
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• 2007

In order to predict the thermal radiation induced from alumina particle cloud in the plume of solid propellant motor, view factor method is applied to space shuttle SRB and the result is compared with that of monte carlo method. For this purpose, radiative characteristics, such as particle cloud temperature distribution, effective emissivity or emissive power of particle cloud are studied. In the case of effective emissivity, inverse wavelength method is applied and plume reduction characteristic length is used for emissive power distribution. As a result, thermal radiation using view factor method gives more conservative results than that using monte carlo method. So it can be used for preliminary design of thermal protection system.

• 한국전기전자재료학회논문지
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• 제27권8호
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• pp.483-485
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• 2014

Transparent amorphous In-Si-O (ISO)/Ag/In-Si-O (ISO) has been reported for low emissivity (low-e) applications. Effective Si doping into the $In_2O_3$ matrix led to a completely amorphous ISO film as well as a low resistivity and a high optical transmittance. The optical and electrical performances were examined by measuring transmittance with a UV-VIS spectrophotometer and resistivity with a Hall effect measurement. Consequently, low-e glass with ISO/Ag/ISO showed a high transparency in the visible region and low emissivity in the infrared region, indicating that ISO is a promising amorphous transparent electrode for low-e glass.

• 한국광학회지
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• 제35권5호
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• pp.228-234
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• 2024

현대의 적외선 유도무기는 표적이 방출하는 적외선을 탐색, 추적하여 표적을 파괴한다. 따라서 적외선 방사율이 낮은 소재로 표적을 덮으면 적외선 신호가 줄어들므로 추적을 피할 수 있다. 그러나 이 방법은 표적이 지표 배경보다 고온일 때만 유효하다. 지표 배경의 온도는 시간대에 따라 크게 변하므로, 표적의 방사율에 따른 표적 신호가 배경 신호보다 작아지는 야간에는 신호 대비에 의해 유도무기 광학계에 발각될 수 있다. 본 연구에서는 지상 표적이 적외선 스텔스를 구현하기 위한 최적 방사율을 지표 배경의 온도 및 방사율, 표적 온도에 따라 계산하고, 표적의 방사율에 따라 달라지는 표적 신호를 고려하여 유도무기 광학계가 수신하는 신호의 크기, 영상의 대비값, 조준 사거리(lock-on range)를 계산하였다. 또한 COMSOL Multiphysics 열영상 전산모사를 통하여 최적 방사율의 유효성을 검증하였다.

• 대한기계학회논문집B
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• 제23권8호
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• pp.1010-1021
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• 1999

Camouflage measures in military purpose utilize the apparent temperature difference between target and background, so it is essential to develop a thermal analysis program for apparent temperature predictions and to apply some camouflage measures to real military targets for camouflage purpose. In this study, a thermal analysis program including conduction, convection and radiation is developed and the validity of radiation heat transfer terms is examined. The results show that longwave radiation along with solar radiation should be included in order to predict the apparent temperature as well as the physical temperature precisely. Longwave emissivity variation as an effective camouflage measures is applied to a real M2 tank. From the simulation results, it is found that an effective surface treatment, such as painting of a less emissive material or camouflage clothing, may provide a temperature similarity or a spatial similarity, resulting in an effective camouflage.

• 대한기계학회논문집B
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• 제23권3호
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• pp.352-363
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• 1999

Target detection by the infrared imager depends on the apparent temperature difference between the target and the background, so it is essential to predict apparent temperature variations for this purpose. In this study, thermal analysis program Including conduction, convection and radiation is developed and applied to a representative geometry adequate for examining the apparent temperature characteristics. The results show that the longwave emissivity in association with the background temperature affects the apparent temperature strongly but does not affect the physical temperature. It is revealed that the background temperature plays a role of tuning the apparent temperature. As the longwave emissivity decreases, the apparent temperature decreases when the target is hotter than the background, whereas it increases in the reversed situation. These findings imply that an effective surface treatment, such as painting of a less emissive material, may provide a less detection probability and contribute to preventing the target from being detected at night.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.657-662
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• 2002

Sea surface temperatures (SSTs) estimated from satellite data are affected by various kinds of disturbance factors. In order to accurately estimate SSTs based on radiometric data observed by satellite, it is important to correct the effects by these disturbance factors. We obtained a huge data set of skin sea surface temperature images observed by a thermal infrared camera (TIC) in MUBEX Campaign. TIC installed on an observation vessel recorded sea surface skin temperature distribution under various weather conditions. Based on some special images observed by TIC, we estimated skin effects and effective sea surface emissivity. In this paper, we report the methods and results of these estimations.