• Journal of the Microelectronics and Packaging Society
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• v.10 no.1
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• pp.39-43
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• 2003

Thermal management is very important for the success of high density circuit design in LTCC. In this paper, LTCC substrates containing thermal via and pad were fabricated in order to study the influence of the thermal dissipation. To realize the accurate thermal analysis for structure design, a series of simple thermal conductivity measurement by laser flash method and parametric numerical analysis have been carried out. The LTCC substrate including via and Ag pad has good thermal conductivity over 103 W/mK which is 44% value of pure Ag material. Thermal behaviors with via arrays, size and density in the LTCC substrate were studied by numerical method.

• Solar Energy
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• v.12 no.1
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• pp.72-80
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• 1992

This paper is concerned with the accurate estimation of the thermal mass effect on the variation of indoor temperature for residential buildings. To carry out the analysis here, the method called "PSTAR(Primary and Secondary Terms Analysis and Renormalization)" has been extensively used. This method was originally developed by the National Renewable Energy Laboratory(NREL) in the United States. The test results reported here represent two extreme cases of the interior thermal mass, which demonstrate its effect on the interior thermal environment as well as on the overall thermal behavior of the building structure. The monthly heating and cooling loads are also extrapolated by using the renormalized model, which are crucial in designing and refurbishing HVAC systems for the building.

• Journal of the Microelectronics and Packaging Society
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• v.22 no.2
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• pp.41-45
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• 2015

RtMLF (Routable Molded Lead Frame) based on molded substrate has been developed to maximize advantages of both leadframe product which has high thermal and electrical performance and laminate product which accommodates more I/O count and keeps fan-in/fan-out design flexibility. Due to its structural features, RtMLF provided excellent thermal and electrical performance which was confirmed with simulation. The RtMLF samples were manufactured and its reliability analysis was done to evaluate the opportunities of the production and application.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1899-1901
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• 2001

본 논문에서는 3차원 feed horn 안테나를 볼로미터에 결합함으로써 감지도(Detectivity)를 향상시킨 비가시광 영상 감지 소자를 제안하였다. Feed horn 안테나의 우수한 지향성(Directivity)를 통해서 주위의 잡음 성분을 제거함으로써 감지도의 향상을 확인할 수 있었다. 안테나와 볼로미터와의 결합 손실을 줄이기 위해서 볼로미터의 흡수층의 모양을 원형의 형태로 하였으며 크기도 안테나 폭과 일치를 시켰다. 또한 열적 고립 구조를 만들기 위한 지지 다리의 모양도 원형의 형태로 하여서 전체 길이를 증가 시켰으며 이로 인해 열전도도(Thermal conductance)를 $4.65{\times}10^{-8}$[W/K]까지 낮출 수 있었 다. 설계된 소자의 감지도는 $2.37{\times}10^{9}$[$cm\sqrt{Hz}/W$]을 나타내었으며 안테나 결합을 통한 감지도의 향상을 확인 할 수 있었다. 볼로미터의 제작은 MEMS 기술을 이용한 표면미세가공(Surface micromachining)법으로 열적 고립 구조체를 제작할 수 있으며 3차원 feed horn안테나는 SU-8이라는 음성 감광제를 경사회전노광시켜서 제작할 수 있다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.32 no.10
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• pp.800-809
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• 2008

Scanning Thermal Microscope (SThM) is the tool that can map out temperature or the thermal property distribution with the highest spatial resolution. Since the local temperature or the thermal property of samples is measured from the extremely small heat transferred through the nanoscale tip-sample contact, improving the sensitivity of SThM probe has always been the key issue. In this study, we develop a new design and fabrication process of SThM probe to improve the sensitivity. The fabrication process is optimized so that cantilevers and tips are made of thermally grown silicon dioxide, which has the lowest thermal conductivity among the materials used in MEMS. The new design allows much higher tip so that heat transfer through the air gap between the sample-probe is reduced further. The position of a reflector is located as far away as possible to minimize the thermal perturbation due to the laser. These full $SiO_2$ SThM probes have much higher sensitivity than that of previous ones.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.11
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• pp.1291-1296
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• 2014

The thermoelectric cooler is receiving great interest because of advantages such as the precise temperature control capability, the compact and lightweight cooler, and the mechanical vibrationless structure which enhances the reliability compared with the existing vapor compression cooler. However, it is not easy to design the optimal thermoelectric cooler which appropriate to the application because the thermal analysis should be necessary required. Accordingly, this paper studies the methodology of the modelling, sizing and thermal analysis of the thermoelectric cooler using SINDA/FLUINT analysis tool.

• Proceedings of the KIEE Conference
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• 2006.10d
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• pp.104-106
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• 2006

Slotless BLDC motor는 Slot과 Teeth가 없으므로 이에 따른 Cogging Torque 및 Torque Ripple이 거의 존재 하지 않으며, 전동기의 무게 또한 감소하게 된다. 또한 권선의 장주(Span)가 짧아 Inductance가 낮기 때문에 고속화가 용이해지며, Slot의 부재는 좀 더 많은 Coil권선을 이용 할 수 있다. 하지만 모터의 구조상 전기장하가 높아짐에 따라 권선의 온도 상승에 대한 보완 등이 필요로 되어 지고 있다. 따라서 본 논문에서는 온도 상승 문제를 해결하기 위해 열 발생과 모터사이의 관계 규명을 전류 밀도 함수로 표시 하였고, 전류 밀도 최소화 설계 방법을 제안하였다. 퍼미언스법에 의한 간략 설계에 의해서 기본 설계를 실시 한 후 FEM을 통한 정밀 해석을 통해서 각각의 민감도를 분석하여 최적의 파라메타를 선정하는 방식을 취하였다. 또한 고속 회전시 발생되는 진동을 저감하기 위해 모터의 길이방향 즉 적층과의 관계를 통하여 진동 저감 설계를 제안하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.10
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• pp.887-894
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• 2016

The thermal control device using solid-liquid phase change material (PCM) is designed, manufactured, and experimented in thermal environment chamber. The n-Hexadecane is selected as a PCM and its melting point is placed within the component working temperature range. The PCM container is made of Al6061 and has the thermal spreading fins inside. To simulate the working condition for on-orbit satellite the heat pipes are used to connect the heater and radiator and the PCM thermal control device (PCMTD) is installed at the middle portion of heat pipes. The thermal buffer mass (TBM), which is same configuration and volume with PCMTD, is also manufactured to compare the thermal control performance. As a result, the PCMTD is not only more efficient than TBM in their temperature control features but both mass and power of compensation heater are reduced.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.12
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• pp.1216-1221
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• 2008

A low earth orbit satellite with a fixed solar array always has a sun-pointing attitude during daylight, and changes into a nadir-pointing attitude for a imaging mission. Since external heating sources to the satellite panels are Earth　irradiation and Albedo during most of daylight in a sun-pointing attitude, the thermal environment condition is relatively stable. However, direct sunlight which is the greatest environmental heating has an affect on the satellite panels during a mission period (10% of one orbit) in a nadir-pointing attitude. In satellite thermal design, thermal effects of a nadir-pointing mission attitude due to this thermal environment change need to be evaluated although the duration of a nadir-pointing attitude is short. Therefore, a nadir-pointing attitude during a mission is incorporated into thermal model and by the thermal analysis result, thermal effects on the satellite are investigated.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.7
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• pp.84-93
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• 2007

The pole transformer is one of the most important facility to insure the stability of electric power supply. which distributes electricity to customers directly. However there are a lot of defects which are caused by manufacturing fails(in 3 years) or deterioration (in 13 years), so we need a more improved transformer which insures quality. This thesis talks about the development of the new-type transformer using the hybrid insulation that is durable thermally, mechanically, and electrically. It would show how to lay out and produce the transformer using the hybrid insulation. And finally we are sure that we could increase the utilization rate of a transformer by 160% as compared with its own capacity through the overload test. Also, we carried out the examination about the short-circuit and insulation with a 100[kVA] model transformer, so that we expound the analysis of magnetic-mechanical forces intensity and the measure for improving short-circuit efficiency.