• Journal of Sensor Science and Technology
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• v.7 no.5
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• pp.356-363
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• 1998

Using the results analyzed by FEM(Finite Element Method). the microheaters with the stress-balanced $Si_3N_4$(150 nm)/$SiO_2$(300 nm)/$Si_3N_4$(150 nm) diaphragms were fabricated by silicon micromachining techniques. Pt was used as microheater materials. Pt temperature sensor was fabricated to measure the temperature of microheaters. Resistance of temperature sensor and power dissipation of microheater were measured and calculated at the various temperatures. The thermal distribution of heater was examined by a IR thermoviewer. Measured and simulated results are compared and analyzed. The temperature coefficient of resistance of heater was about $0.00379/^{\circ}C$. Pt heater showed the power dissipation of about 51 mW at $300^{\circ}C$ and a uniform thermal distribution on the surface.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.12
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• pp.1435-1440
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• 2014

This paper was designed to analyze thermal properties using thermoelectric element for air-cooling heat dissipation of 13.2W-class COB LED. For comparative analysis with generally used air cooling methods, the heat sink was designed and produced, and this experiment was conducted to measure the temperature distribution using a contact thermometer while the COB LED was operating for 100 minutes. One result was about $75^{\circ}C$ for the general cooling method, and the other was $57^{\circ}C$ while the thermoelectric element was operating with applying the current of 0.8A to the thermoelectric element. This results confirmed that the method of applying thermoelectric element was much better in the dissipation of thermal condense on the COB LED than that of the general air cooling one. The temperature on the contact points of COB LED using thermoelectric element was decreased about 31% compared with the air cooling method from $75^{\circ}C$ to $57^{\circ}C$.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2444-2448
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• 2007

The multi channel of DDI which is the core part of the LCD-TV has been propelled. When multi channel in DDI is introduced, it brings a thermal problem because of the increased power. To solve the thermal problem of the DDI it needs to be investigated each at the package level and module level. It is important to extract the junction temperature(Tj) of DDI clearly from the system level. The objective of this research is to construct a compact model. The compact model is to reduce LCD module including DDI. When the compact model is used, it will be able to easily handle the boundary condition and accurately predict the temperature. Consequently, the temperature of DDI can be calculated easily at the system level. Through this research,we also proposed the cooling plan of DDI for a protection of overheating. The cooling plan was utilized in DDI design.

• Journal of the Korean institute of surface engineering
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• v.28 no.2
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• pp.67-76
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• 1995

The microstructure of 95wt.%Pb/5wt.%Sn and 63wt.%Sn/37wt.%Pb solders for flip chip bonding process has been characterized. Solders were deposited by thermal evaporation and reflowed in the conventional furnace or by rapid thermal annealing(RTA) process. As-deposited films show columnar structure. The microstructure of furnace cooled 63Sn/37Pb solder shows typical lamellar form, but that of RTA treated solder has the structure showing an uniform dispersion of Pb-rich phase in Sn matrix. The grain size of 95Pb/5Sn solder reflowed in the furnace is about $5\mu\textrm{m}$, but the grain size of RTA treated solder is too small to be observed. The microstructure in 63Sn/37Pb solder bump shows the segregation of Pb phase in the Sn rich matrix regardless of reflowing method. The 63Sn/37Pb solder bump formed by RTA process shows more uniform microstructure. These result are related to the heat dissipation in the solder bump.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.7
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• pp.2356-2366
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• 1996

High-power electronic chips have been advanced to such an extent that the heat dissipation capability of a system design has become one of the primary limiting factors. Therefore, thermal design must be considered in the early stage of the electronic system development. In present paper, the results of an experimental study on the forced convection cooling are presented to evaluate cooling performance of an electronic cabinet which in generally used for telecommunication system. Temperatures and thermal resistances are applied to compare the heat transfer characteristics for various locations of a fan unit as well as various configuration of non-uniform powering modules. As a result, the optimal configuration of a fan unit and powering configuration is suggested for the effective thermal design of telecommunication system.

• Transactions of the Korean Society of Mechanical Engineers
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• v.7 no.4
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• pp.451-460
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• 1983

Computational four-equation turbulence model is developed and is applied to predict twodimensional unsteady thermal surface discharge into a reservoir. Turbulent stresses and heat fluxes in the momentum and energy equations are determined from transport equations for the turbulent kinetic energy (R), isotropic rate of kinetic energy dissipation (.epsilon.), mean square temperature variance (theta. over bar $^{2}$), and rate of destruction of the temperature variance (.epsilon. $_{\theta}$). Computational results by four-equation model are favorably compared with those obtained by an extended two-equation model. Added advantage of the four-equation model is that it yields quantitative information about the ratio between the velocity time scale and the thermal time scale and more detailed information about turbulent structure. Predicted time scale ratio is within experimental observations by others. Although the mean velocity and temperature fields are similarly predicted by both models, it is found that the four-equation model is preferably candidate for prediction of highly buoyant turbulent flows.

• Vacuum Magazine
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• v.4 no.3
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• pp.16-20
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• 2017

Graphene has emerged as a promising material for optoelectronic applications including as ultrafast and broadband photodetector, optical modulator, and nonlinear photonic devices. Graphene based devices have shown the feasibility of ultrafast signal processing for required for photonic integrated circuits. However, on-chip monolithic nanoscale light source has remained challenges. Graphene's high current density, thermal stability, low heat capacity and non-equilibrium of electron and lattice temperature properties suggest that graphene as promising thermal light source. Early efforts showed infrared thermal radiation from substrate supported graphene device, with temperature limited due to significant cooling to substrate. The recent demonstration of bright visible light emission from suspended graphene achieve temperature up to ~3000 K and increase efficiency by reducing the heat dissipation and electron scattering. The world's thinnest graphene light source provides a promising path for on-chip light source for optical communication and next-generation display module.

• Tribology and Lubricants
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• v.18 no.6
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• pp.384-388
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• 2002

The adequate design of a passenger car braking system, which is directly related to the safety of a car, is very important since the safety is an essential design parameter of a car to keep men and car from the damage. The thermal behaviors of the ventilated disk has been investigated based on the air cooling effects during repeat braking operations. In this study, the thermal behavior of ventilated disk brake system was investigated by numerical method. The 3-Dimensional unsteady model was simulated by using a general purpose software package “FLUENT” to obtain the temperature distributions of disk and pad. The model includes the more realistic braking method, which repeats braking and release. The effects of aspect ratio of ventilated hole on the heat dissipation was investigated.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.4
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• pp.49-55
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• 2016

Nowadays there are magnetic sensors in a wide variety of equipment such as computers, cars, airplanes, medical and industrial instruments. In many of these applications the magnetic sensors offer safe and non-invasive means of detection and are more reliable than other technologies. The electric current in a conductor generates a magnetic field detected by this type of sensor. This work aims to define a package dedicated to an electrical current sensor using a MTJ (Magnetic Tunnel Junction) as a sensing device. Four different proposals of packaging, three variations of the chip on board (CoB) package type and one variation of the thin small outline package (TSOP) were analyzed by COMSOL modeling software by simulating a brad range of current injection. The results obtained from the thermal and magnetic analysis has proven to be very important for package improvements, specially for heat dissipation performance.

• Electronics and Telecommunications Trends
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• v.10 no.1 s.35
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• pp.47-57
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• 1995

최근 전자 및 통신기기에는 시스템의 소형화, 고기능 및 고신뢰도를 실현하기 위하여 하나의 기판위에 여러개의 chip을 장착하는 다중칩 패키지 기술이 사용되고 있다. 그러나 이로 인하여 기판 면적당 칩수의 증가로 power dissipation이 증가하게 되었으며, 이러한 power의 증가는 온도를 상승시켜서 시스템의 신뢰도를 저하시키는 원인이 되고 있기 때문에 이에 대한 열 해석이 요구되어진다. 따라서 본 고에서는 다중칩 패키지의 열 성능을 위하여 전도성이 좋은 세라믹 기판의 과도 온도 특성을 해석하고자, 전기적 유사 회로를 이용하여 thermal via가 없는 경우와 있는 경우에 대하여 열전달 특성을 고찰하였다. 그 결과 themal via에 의한 기판의 열전달 향상으로 다중칩 패키지의 동작 온도가 낮아짐을 알 수 있었다.