• Structural Monitoring and Maintenance
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• 제3권3호
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• pp.277-296
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• 2016

There is a need for rapid and objective assessment of concrete bridge decks for maintenance decision making. Infrared Thermography (IRT) has great potential to identify deck delaminations more objectively than routine visual inspections or chain drag tests. In addition, it is possible to collect reliable data rapidly with appropriate IRT cameras attached to vehicles and the data are analyzed effectively. This research compares three infrared cameras with different specifications at different times and speeds for data collection, and explores several factors affecting the utilization of IRT in regards to subsurface damage detection in concrete structures, specifically when the IRT is utilized for high-speed bridge deck inspection at normal driving speeds. These results show that IRT can detect up to 2.54 cm delamination from the concrete surface at any time period. It is observed that nighttime would be the most suitable time frame with less false detections and interferences from the sunlight and less adverse effect due to direct sunlight, making more "noise" for the IRT results. This study also revealed two important factors of camera specifications for high-speed inspection by IRT as shorter integration time and higher pixel resolution.

• Journal of Astronomy and Space Sciences
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• 제21권4호
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• pp.467-480
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• 2004

KAONICS(KAO Near Infrared Camera System)와 같은 적외선 카메라는 열잡음제거가 매우 중요하다. 입사창을 통해 들어오는 외부의 열복사 이외에도 카메라의 외벽을 통해 유입되는 열복사가 배경복사로서 검출기에 입사하여 시스템의 성능을 저하 시키며 그 양은 무시할 수 없다. 따라서 배경복사와 검출기 자체의 열잡음을 줄이기 위해서 카메라 내부의 광학계 전체와 검출기를 냉각해야만 한다. 이에 본 연구에서는 J, H, Ks, L 파장 대를 관측하기 위한 내부 냉각온도를 정량적으로 결정하였으며 카메라 외부에서 유입되는 복사량을 추산하고 냉각에 필요한 냉각 열용량을 추정하여 냉각기를 선택하였다. 선택된 냉각기를 이용하여 냉각할 때 Cold-Box가 목표온도에 도달하는 시간과 최종 냉각 온도를 계산하여 시스템 제작에 반영하였다.

• 천문학회보
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• 제39권1호
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• pp.50.1-50.1
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• 2014

The Multi-purpose InfraRed Imaging System (MIRIS) is the main payload of Science and Technology Satellite 3 (STSAT-3), which was launched onboard Dnepr rocket from Russian Yasny Launch Base in November 2013. The MIRIS is an infrared (IR) camera, and the telescope has to be cooled down to below 200K in order to reduce thermal background noise. For the effective cooling and low-power consumption, we applied passive cooling method to the thermal design of the MIRIS. We also conducted thermal analysis and tested for the passive cooling before the launch of STSAT-3. After the launch, we have received State-of-Health (SOH) data from the satellite on orbit, including temperature monitoring results. It is important that the temperature of the telescope was shown to be cooled down to below 200K. In this paper, we present both the temperature data of the MIRIS on orbit and the thermal analysis results in the laboratory. We also compare these results and discuss the verification of the passive cooling.