• Title/Summary/Keyword: Heat SinK

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Heat Analysis of Welding-bead using Infrared Thermoimage Camera (적외선 열화상 카메라를 이용한 용접 비드의 열 해석)

  • Kim, Jae-Yeol;Shim, Jae-Gi;Yang, Dong-Jo;Yu, Sin
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2000.10a
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    • pp.57-62
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    • 2000
  • Diagnosis or measurements using Infrared thermoimage hasn't been available. A quick diagnosis and thermal analysis can be possible when that kind of system is introduced to the investigation of each part. In this study, Infrared Camera, Thermovision 900 was used in order to investigate. Infrared Camera usually detects only Infrared wave from the light in order to illustrate the temperature distribution. Infrared diagnosis system can be applied to various field. Also, it is more effective to analyze temperature distribution on the welding parts during welding process. Especially, diagnosis using Infrared camera plays an important role on thermal analysis of Axle Casing Nut for Commercial Vehicles.

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An Analysis of a Post-Trip Return-to-Power Steam Line break Events

  • Baek, Seung-Su;Lee, Cheol-Sin;Song, Jin-Ho;Lee, Sang-Yong
    • Proceedings of the Korean Nuclear Society Conference
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    • 1995.05a
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    • pp.544-549
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    • 1995
  • An analysis for Steam Line Break (SLB) events which result in a return-to-power conditions after reactor trip was performed for a postulated Yonggwang Nuclear Power Plant Unit 3 cycle 8. Analysis methodology for post-trip return-to-power SLB is quite different from that of a no return-to-power SLB and is more complicated. Therefore, it is necessary to develop an methodology to analyze the response of the NSSS parameter and the fuel performance for the post-trip return-to-power SLB events. In this analysis, the cases with and without offsite power were simulated by crediting 3-D reactivity feedback effect due to local heatup around stuck CEA and compared with the cases without 3-D reactivity feedback with respect to fuel performance, departure from nucleate boiling ratio (DNBR) and linear heat generation rate (LHGR).

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Changes in the Body Temperature by tow-Frequency-Wave Stimulation at the Pericardium Meridian Hand jueyin

  • Kim, Eun-Sung;Jun, Sang-Hyun;Kang, Sin-In;Park, Chang-Ho
    • 한국생물공학회:학술대회논문집
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    • 2005.04a
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    • pp.75-79
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    • 2005
  • Temperature decrease upon Low-Frequency-Wave stimulation at PC4 and PC8 of the Pericardium Meridian of hand jueyin indicated that body heat dissipated along the Meridian. The temperature difference between PC4 and PC8 was smaller at 50Hz compared with that of 100Hz. No further increase in temperature difference was absorbed at 150Hz.

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Fixed-Grid Simulation of Convection-Dominated Melting in a Rectangular Cavity

  • Wongee Chun;Kim, Sin;Kim, Min-Chan
    • Journal of Mechanical Science and Technology
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    • v.15 no.6
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    • pp.796-803
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    • 2001
  • Numerical solutions for the convection-dominated melting in a rectangular cavity are presented. The enthalpy-porosity model is employed as the mathematical model. This model is applied in conjunction with the EIT method to detect boundary movement in a phase changing environment. The absorption and evolution of latent heat during the phase change is dealt with by the enthalpy-based energy equation. This seems to be more efficient than resolving the temperature-based energy equation. The velocity switch-off, which is required when solid changes into liquid, is modeled by the porous medium assumption. For efficiency and simplicity of the solutions procedure, this paper proposes a simple algorithm, which iterates the temperature and the liquid fraction of the cells comprising the front layer. The numerical results agree reasonably well with the experimental data and other previous works using the transformed-grid system.

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The Buoyancy Effects in Horizontal Porous Layers with Vortical Through Flow (수직 투과 흐름이 있는 수평 다공질 유체층에서의 부력 효과)

  • Kim, Min-Chan;Kim, Sin;Yoon, Do-Young;Kim, Sae-Hoon
    • Journal of Energy Engineering
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    • v.10 no.3
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    • pp.266-271
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    • 2001
  • Buoyancy-driven natural convection is analysed by employing a linear stability theory in hori-zontal porous media with net through flow. Darcy's law is used to model the flow characteristics in porous media. Bated on the results of linear stability analysis, a heat transfer correlation was obtained by employing weakly nonlinear analysis. As the net through flow increases, the system becomes more stable and the effect of the Darcy-Rayleigh number on the Nusselt number decreases.

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Three-dimensional analysis of the thermophoretic particle deposition in the OVD process (외부증착공정에서의 열영동에 의한 입자부착에 관한 3차원 해석)

  • Hong, Gi-Hyeok;Gang, Sin-Hyeong
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.21 no.3
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    • pp.436-444
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    • 1997
  • Three-dimensional conjugate heat transfer and particle deposition on a circular cylinder in the OVD process are numerically investigated. Flow and temperature fields are obtained by an iterative method, and thermophoretic particle deposition is simulated. Effects of the heat conduction in the cylinder, the rotation speed of the cylinder, and the traversing speed of torch on the deposition are studied. Effects of variable properties are also included. As the conductivity of the cylinder decreases, particle deposition rate and deposition efficiency greatly decrease due to the reduced temperature gradient. The rotation of the cylinder has no significant effect on the deposition due to the small diameter of the cylinder and low speed of rotation. Since the increase of the torch speed keeps the surface low temperature, the particle deposition increases with the traversing speed.

Recent Progress in Air Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2007 (설비공학 분야의 최근 연구 동향 : 2007년 학회지 논문에 대한 종합적 고찰)

  • Han, Hwa-Taik;Shin, Dong-Sin;Choi, Chang-Ho;Lee, Dae-Young;Kim, Seo-Young;Kwon, Yong-Il
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.20 no.12
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    • pp.844-861
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    • 2008
  • The papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during the year of 2007 have been reviewed. Focus has been put on current status of research in the aspect of heating, cooling, ventilation, sanitation and building environments. The conclusions are as follows. (1) The research trends of fluid engineering have been surveyed as groups of general fluid flow, fluid machinery and piping, etc. New research topics include micro nano fluid, micropump and fuel cell. Traditional CFD was still popular and widely used in research and development. Studies about fans and pumps were performed in the field of fluid machinery. Characteristics of flow and fin shape optimization are studied in the field of piping system. (2) The research works on heat transfer have been reviewed in the field of heat transfer characteristics, heat exchangers, and desiccant cooling systems. The research on heat transfer characteristics includes thermal transport in pulse tubes, high temperature superconductors, ground heat exchangers, fuel cell stacks and ice slurry systems. For the heat 'exchangers, the research on pin-tube heat exchanger, plate heat exchanger, condensers and gas coolers has been cordially implemented. The research works on heat transfer augmenting tubes have been also reported. For the desiccant cooling systems, the studies on the design and operating conditions for desiccant rotors as well as performance index are noticeable. (3) In the field of refrigeration, many papers were presented on the air conditioning system using CO2 as a refrigerant. The issues on the two-stage compression, the oil selection, and the appropriate oil charge were treated. The subjects of alternative refrigerants were also studied steadily. Hydrocarbons, DME and their mixtures were considered and various heat transfer correlations were proposed. (4) Research papers have been reviewed in the field of building facilities by grouping into the researches on heat and cold sources, air conditioning and air cleaning, ventilation and fire research including tunnel ventilation, flow control of piping system, and sound research with drain system. Main focuses have been addressed to the promotion of efficient or effective use of energy, which helps to save energy and results in reduced environmental pollution and operating cost. (5) Studies were mostly focused on analyzing the indoor environment in various spaces like cars, old tombs, machine rooms, and etc. in an architectural environmental field. Moreover, subjects of various fields such as the evaluation of noise, thermal environment, indoor air quality and development of energy analysis program were researched by various methods of survey, simulation, and field experiment.

Adhesion and Agglomeration Phenomena of Pt Film of Resistance Heat Source (저항열원체 Pt 박막의 밀착력과 응집화 현상)

  • Lee, Jae-Seok;Park, Hyo-Deok;Sin, Sang-Mo;Park, Jong-Wan
    • Korean Journal of Materials Research
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    • v.6 no.2
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    • pp.204-209
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    • 1996
  • 각종 전자부품에 이용되는 백금막의 밀착력과 응집화 현상에 대해 연구하였다. 온도저항계수(TCR)의 열화 없이 밀착력을 향상 시키기 위해서 AI, Si의 산화물을 adhesion promoting layer로 이용한 결과 매우 우수한 밀착력과 TCR을 보였다. 질소분위기 600-90$0^{\circ}C$의 온도범위에서 행한 열처리를 통해 응집화현상을 관찰한 결과 응집화는 기판거칠기에 따라 다른 양상을 보였다. Si3N4등의 기판거칠기가 작은 adhesion promoting layer를 이용한 시편의 경우 고온인 90$0^{\circ}C$에서 응집화 현상이 발생되었다. 표면거칠기가 큰 AI-Si 산화물을 adhesion promoting layer로 이용한 시편의 경우 비교적 저온인 $600^{\circ}C$에서 응집화 현상이 발생했으며 80$0^{\circ}C$이상의 열처리의 경우 중앙응집체와 응집체고갈지역이 형성되는 현상을 나타내었다.

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Effects of Heat Treatments on the Physical Properties of Polycrystalline CdTe Thin Film (다결정 CdTe 박막의 열처리에 따른 물성 변화에 관한 연구)

  • Kim, Hyeon-Su;Yeom, Geun-Yeong;Sin, Seong-Ho;Park, Jeong-Il;Park, Gwang-Ja
    • Korean Journal of Materials Research
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    • v.5 no.4
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    • pp.389-396
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    • 1995
  • 본 논문에서는 전자빔증착법에 의해 제조된 다결정 CdTe 박막의 구조적, 광학적 특성을 연구하였으며 특히 기판온도와 증착후 열처리에 따른 박막의 결정성변화를 관찰하고 그 결과를 고찰하였다. ITO와 유리위에 25~16$0^{\circ}C$의 기판온도로 증착된 CdTe 박막의 결정구조는 zinc blende 구조를 보이고 <111> 방향으로의 우선 성장방향을 나타내었다. 증착후 열처리를 함에 따라 결정립이 성장하고 정량적 CdTe로 접근하고 상온에서 band gap 이 단결정의 값인 1.5eV에 가까운 에너지로 천이하며 결정성이 향상됨을 관찰할 수 있었다. 이러한 열처리에 의한 결정성 향상은 PL과 XRD를 통하여 분석한 결과 재료내 존재하는 과잉 Te가 열처리시 증발함에 따라 격자내 응력이 감소함과 관련이 있음을 알 수 있었다.

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A study on optical measurement system with high precision and product of Near-Field Scanning Optical Microscope (고정밀 광계측 시스템 연구 및 근접장 주사 광학현미경의 제작)

  • Sin, Dong-Min;HwangBo, Soung
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.1743-1744
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    • 2008
  • NSOM(Near-field Scanning Optical Microscopy) 조화 진동자(Tuning fork)와 광섬유 탐침을 결속시켜 미소신호를 검출하여 증폭과 잡음을 제거하기 위한 Pre-amplifier의 설계 및 제작과 더불어 시료-탐침간 거리를 파장보다 짧게 유지시키는 Shear force 검출, 효율적인 시료-탐침 거리유지 알고리즘 구연 및 탐침을 시료 표면에서 일정한 거리를 안정적으로 유지하도록 제어 및 시료의 높이 정보를 얻어내는 시스템을 설계 및 제작하였다. 또한 ����$CO_2Laser$를 이용한 Heat Pulling 장치개발을 통해 탐침을 제작, LabVIEW를 통해 개별적인 시스템을 하나로 통합하여 AFM 테스트 시료인 SiO 샘플의 표면 형상을 측정하였다.

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