• Title/Summary/Keyword: 열적환경

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Bithmooth Based Glass System for Transparent Dielectric in Plasma Display Panel ($Bi_2O_3-ZnO-SiO_2$ 유리계의 PDP 투명유전체에 적용 가능성)

  • 전재삼;차명룡;정병해;김형순
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2003.11a
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    • pp.196-196
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    • 2003
  • 현재 PDP(Plasma Display Panel) 상판의 유전체층은 저온에서 소성이 가능한 저융점 유리가 요구되기 때문에 융점을 낮추기에 용이한 PbO계가 주 성분으로 사용되어 오고 있으나. 최근 환경오염 등의 문제점으로 인해 Pb-free을 추구하는 새로운 유리조성의 연구가 많이 수행되고 있다. 이에 본 연구는 이미 PDP의 격벽과 봉착용 조성으로 많이 연구되어진 비스무스계 유리를 고려하여 PDP의 투명유전체용 조성을 찾고자 한다. Bi$_2$O$_3$-ZnO-SiO$_2$3원계를 기본으로 하는 유리조성에 유리망목형성제등을 첨가하여 열적특성과 광학적 특성을 조사하였다. 열적특성은 DTA를 이용하여 유리 전이 점(Tg) 및 융점(Tl)등을 측정하였고 TMA를 이용하여 선팽창계수(CTE)를 측정하였으며 유리섬유를 제조한 후 Littleton softening point (Ts)를 측정하였다. 광학적 특성은 페이스트를 제조하여 스크린프린팅 후 54$0^{\circ}C$~$600^{\circ}C$에서 1-2 h동안 소성하여 투광성을 조사하였다. 그 결과로, 열적특성으로는 400~5$50^{\circ}C$의 Tg, 450~$600^{\circ}C$의 Ts 및 5~11$\times$$10^{-6}$K의 CTE 값을 나타 내었고 광학적 특성으로 투광성은 양호한 특성(60% 이상)을 나타내었다. Bi$_2$O$_3$ 계를 현재 PDP의 투명유 전체에 적용시키기에는 유리용융시에 높은 점도와 환원 등의 문제점을 갖고 있지만 열적특성과 광학특성면에서는 가능성을 제시하여 향후 연구를 할 가치가 있다고 본다.

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Study of Micro Propulsion System Based on Thermal Transpiration (열적발산원리를 이용한 마이크로 추진장치에 대한 연구)

  • Jung, Sung-Chul;Shin, Kang-Chang;Kim, Youn-Ho;Kim, Hye-Hwan;Lee, Yong-Wu;Huh, Hwan-Il
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2007.04a
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    • pp.25-29
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    • 2007
  • Minimization of conventional propulsion device has been studied for altitude control of micro satellite. We studied micro nozzle performance and found higher significant loss for a micro nozzle with smaller nozzle throat diameter. To overcome this loss, we proposed thermal transpiration based micro propulsion system. This new system has no moving parts and can control flow by temperature gradient, and this can be an option for potential new micro propulsion system.

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Comparing Physical and Thermal Environments Using UAV Imagery and ENVI-met (UAV 영상과 ENVI-met 활용 물리적 환경과 열적 환경 비교)

  • Seounghyeon KIM;Kyunghun PARK;Bonggeun SONG
    • Journal of the Korean Association of Geographic Information Studies
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    • v.26 no.4
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    • pp.145-160
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    • 2023
  • The purpose of this study was to compare and analyze diurnal thermal environments using Unmanned Aerial Vehicles(UAV)-derived physical parameters(NDVI, SVF) and ENVI-met modeling. The research findings revealed significant correlations, with a significance level of 1%, between UAV-derived NDVI, SVF, and thermal environment elements such as S↑, S↓, L↓, L↑, Land Surface Temperature(LST), and Tmrt. In particular, NDVI showed a strong negative correlation with S↑, reaching a minimum of -0.52** at 12:00, and exhibited a positive correlation of 0.53** or higher with L↓ at all times. A significant negative correlation of -0.61** with LST was observed at 13:00, suggesting the high relevance of NDVI to long-wavelength radiation. Regarding SVF, the results showed a strong relationship with long-wave radiative flux, depending on the SVF range. These research findings offer an integrated approach to evaluating thermal comfort and microclimates in urban areas. Furthermore, they can be applied to understand the impact of urban design and landscape characteristics on pedestrian thermal comfort.

The Comparison of Thermal Infrared Satellite Observation for Plume Assessment of Thermal Discharge (온배수 확산 평가를 위한 열적외선 위성관측 비교)

  • Jeong, Jong-Chul
    • Journal of Environmental Impact Assessment
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    • v.24 no.4
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    • pp.367-374
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    • 2015
  • To examine the effect of thermal discharge from nuclear power plants, Sea Surface Temperature (SST) is one of the most important variables measured by satellite remote sensing. However, the study was not much comparison of field data and satellite SST from operational Landsat 8 Thermal Infrared Sensor(TIRS) and Landsat 7 ETM+. The Landsat 8 TIRS have 2 spilt Thermal Infrared channels but ETM+ uses one channel for extracting of SST. In spite of that this research carried out that Landsat 7 ETM+ have more profitable for correction of SST than Landsat 8 TIRS. The used 15 Landsat 7 and 8 Thermal Infrared data of path/row 114-36 were processed by SST algorithm of ENVI and IDL. The in-situ SST data from KHOA(Korea Hydrographic and Oceanographic Administration) compared with satellite SST and the accuracy of extracted SST were assessed by each field sites in-situ point data with time series satellite SST.

Extraction of Sea Surface Temperature in Coastal Area Using Ground-Based Thermal Infrared Sensor On-Boarded to Aircraft (지상용 열적외선 센서의 항공기 탑재를 통한 연안 해수표층온도 추출)

  • Kang, Ki-Mook;Kim, Duk-Jin;Kim, Seung Hee;Cho, Yang-Ki;Lee, Sang-Ho
    • Korean Journal of Remote Sensing
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    • v.30 no.6
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    • pp.797-807
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    • 2014
  • The Sea Surface Temperature (SST) is one of the most important oceanic environmental factors in determining the change of marine environments and ecological activities. Satellite thermal infrared images can be effective for understanding the global trend of sea surface temperature due to large scale. However, their low spatial resolution caused some limitations in some areas where complicated and refined coastal shapes due to many islands are present as in the Korean Peninsula. The coastal ocean is also very important because human activities interact with the environmental change of coastal area and most aqua farming is distributed in the coastal ocean. Thus, low-cost airborne thermal infrared remote sensing with high resolution capability is considered for verifying its possibility to extract SST and to monitor the changes of coastal environment. In this study, an airborne thermal infrared system was implemented using a low-cost and ground-based thermal infrared camera (FLIR), and more than 8 airborne acquisitions were carried out in the western coast of the Korean Peninsula during the periods between May 23, 2012 and December 7, 2013. The acquired thermal infrared images were radiometrically calibrated using an atmospheric radiative transfer model with a support from a temperature-humidity sensor, and geometrically calibrated using GPS and IMU sensors. In particular, the airborne sea surface temperature acquired in June 25, 2013 was compared and verified with satellite SST as well as ship-borne thermal infrared and in-situ SST data. As a result, the airborne thermal infrared sensor extracted SST with an accuracy of $1^{\circ}C$.

Thermal Characteristics of Nutrient Solution and Root Media in Recycled Soilless Culture Systems (순환형 무토양재배시스템 양액 및 배지의 열적 특성)

  • 손정익;장진택;이병일
    • Proceedings of the Korean Society for Bio-Environment Control Conference
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    • 1997.05a
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    • pp.59-61
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    • 1997
  • 무토양재배시스템은 가급적 경량화이면서 집약적인 형태를 가지며, 환경보존차원을 위하여 밀폐형 순환식 재배시스템이 중시되고 있다. 무토양재배시스템은 DFT에서 NFT나 고형배지로 갈수록 외기의 환경변화에 대하여 비교적 근권부근의 환경변화가 크기 때문에 노출되어 있는 뿌리에 영향을 미치는 것으로 사료된다. (중략)

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