• Title/Summary/Keyword: 열 저항값

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A Study on Development of the Wire-Harness Checker Using Open Source (오픈소스를 이용한 배선조립체 점검기 개발에 관한 연구)

  • Yoon, Myung-Seob;Park, Koo-Rack;Kim, Jae-woong;Lee, Yun-Yeol
    • Proceedings of the Korean Society of Computer Information Conference
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    • 2019.01a
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    • pp.295-296
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    • 2019
  • 본 논문은 항공기내의 주요 항공전기 전자 부분품을 연결하여 주는 배선조립체의 연속성을 시험할 수 있는 점검기의 개발에 관한 것이다. 기존의 항공기 내의 배선조립체의 연속성 시험은 디지털 멀티미터의 저항점검 기능을 통해 이루어지고 있었으나, 측정된 저항값이 정상인지 비정상인지의 판단은 정비사의 경험에 의한 판단에 의존할 수밖에 없는 문제가 있다. 제안한 점검기는 정비사가 예상되는 배선의 AWG 규격 및 길이를 입력하면 배선조립체의 AWG 규격별, 길이별 SPEC'의 저항값을 계산하여 측정된 저항값이 정상인지 비정상인지 확인할 수있는 메시지를 시현하게 하여 정비사의 정비 부담을 줄여줄 수 있다. 또한 본 시스템은 오픈소스를 이용하여 저비용으로 제작가능하게 하여 많은 정비사들이 사용할 수 있도록 하는 장점이 있다.

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A design of predistortion linearizer using the feedback (Feedback 방식을 이용한 전치왜곡기 설계)

  • 남윤관;조범식;권성수;강원석;오인열
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • 2000.11a
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    • pp.202-205
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    • 2000
  • 본 논문에서는 IMT-2000용 고전력 중폭기에 사용할수 있근 전치 왜곡기를 feedback 방식을 이용하여 설계하였다. 여기서 feedback 방식을 사용함으로써 기존의 전치 왜곡기와는 달리 증폭기의 이득을 조절하기 위해 감쇄기를 사용하지 않고 feedback에 사용한 저항값을 사용하여 이득을 조절하도록 설계하였다.

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Measurement of Thermal Characteristics of Thin Film Patterned Heating Heater on Silicon Semiconductor Substrate (실리콘 반도체 기판에 제작된 박막 패턴 발열 히터의 열특성 측정)

  • Park, Hyun-Sik
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.6
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    • pp.9-13
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    • 2019
  • In this study, a miniature thin film-patterned heater was fabricated on a silicon substrate using semiconductor process technology and the thermal characteristics of the applied voltage, power, and temperature of the thin film heater were measured and analyzed. The temperature of the thin film pattern heater increased with increasing power, but the temperature increase rate was gradual at high power intervals. The characteristics of the high temperature section of the platinum thin film-patterned heater were analyzed using the heat resistance model under atmospheric and vacuum conditions. The thermal resistance measured in a vacuum atmosphere was 0.79 [K/mW] higher than the heat resistance value 0.69 [K/mW] in air. The temperature of the thin film pattern heater can be maintained at a low power in a vacuum rather than in air, and these results are expected to be utilized in the structural design of a thin film-patterned heater element.

Comparative Study on the Thermal Insulation of Membrane LNG CCS by Heat Transfer Analysis (열전달 해석을 이용한 멤브레인형 LNG 화물창의 단열구조 성능비교)

  • Hwang, Se-Yun;Lee, Jang-Hyun
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.29 no.1
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    • pp.53-60
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    • 2016
  • This study discusses the thermal insulation capacity of variant of NO96 LNG (liquefied natural gas) cargo containment insulation system. Changing the insulation materials and the insulation layers of conventional GTT NO96 containment system, The thermal resistance and BOR(boil off rate) caused by the heat transfer between cryogenic and environmental temperature is discussed. Therefore, thermal analysis of LNG CCS(cargo containment system) is carried out to determine the insulation capabilities. Also, BOR is evaluated in terms of the total amount of heat invaded into CCS(cargo containment system). Variant of NO96 CCS such as NO96, NO96GW and NO96L3 membrane type during laden voyage is selected for the comparative study. Finite element model for heat transfer analysis is conducted by employing the equivalent thermal resistance model to simplify the complex insulation layers. Finally the results for each variant model are relatively compared and discussed to minimize the BOR.

Optimization of the Backfill Materials for Underground Power Cables considering Thermal Resistivity Characteristics (I) (열저항 특성을 고려한 지중송전관로 되메움재의 최적화(I))

  • Kim, You-Seong;Cho, Dae-Seong;Park, Young-Jun
    • Journal of the Korean Geosynthetics Society
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    • v.10 no.4
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    • pp.113-121
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    • 2011
  • River sand has generally used for the backfill material of underground power cables. The thermal resistivity of it has $150^{\circ}C$-cm/Watt in wet condition and more than double in dry condition. The final goal of this study is to find the backfill material which has a small change in thermal resistivity with various water contents, for example thermal resistivity is $50^{\circ}C$-cm/Watt and $100^{\circ}C$-cm/Watt in wet and dry conditions respectively. In this study it is presented that the comparison of thermal resistivity using stone powder, crush rock, weathered granite soil and Jumunjin sand as well as river sand in the needle method regarding water content, dry unit weight and particle size distribution. As a result, the thermal resistivity of a material is minimized when they have maximum dry unit weight at optimum moisture content and maximum density by appropriately mixing materials for particle size distribution. Therefore thermal resistivity characteristics should be considered two factors: one is the difference between natural dry condition and dry state after optimum moisture content, and the other is the difference between unit weight of raw material and maximum dry density.

Evaluation of Compaction and Thermal Characteristics of Recycled Aggregates for Backfilling Power Transmission Pipeline (송배전관로 되메움재로 활용하기 위한 국내 순환골재의 다짐 및 열적 특성 평가)

  • Wi, Ji-Hae;Hong, Sung-Yun;Lee, Dae-Soo;Park, Sang-Woo;Choi, Hang-Seok
    • Journal of the Korean Geotechnical Society
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    • v.27 no.7
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    • pp.17-33
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    • 2011
  • Recently, the utilization of recycled aggregates for backfilling a power transmission pipeline trench has been considered due to the issues of eco-friendly construction and a lack of natural aggregate resource. It is important to identify the physical and thermal properties of domestic recycled aggregates that can be used as a backfill material. This paper evaluated thermal properties of concrete-based recycled aggregates with various particle size distributions. The thermal properties of the recycled aggregates and river sand provided by local vendors were measured using the transient hot wire method and the transient needle probe method after performing the standard compaction test. The needle probe method considerably overestimated the thermal resistivity of recycled aggregates especially at the dry of optimum water content because of experiencing disturbance while the needle probe is being inserted into the specimen. Similar to silica sand, the thermal resistivity of recycled aggregates decreased when the water content increased at a given dry density. Also, this paper evaluated some of the existing prediction models for the thermal resistivity of recycled aggregates with the experimental data, and developed a new prediction model for recycled aggregates. This study shows that recycled aggregates can be a promising backfill material substituting for natural aggregates when backfilling the power transmission pipeline trench.

Molecular Dynamics Simulation on the Thermal Boundary Resistance of a Thin-film and Experimental Validation (분자동역학을 이용한 박막의 열경계저항 예측 및 실험적 검증)

  • Suk, Myung Eun;Kim, Yun Young
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.32 no.2
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    • pp.103-108
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    • 2019
  • Non-equilibrium molecular dynamics simulation on the thermal boundary resistance(TBR) of an aluminum(Al)/silicon(Si) interface was performed in the present study. The constant heat flux across the Si/Al interface was simulated by adding the kinetic energy in hot Si region and removing the same amount of the energy from the cold Al region. The TBR estimated from the sharp temperature drop at the interface was independent of heat flux and equal to $5.13{\pm}0.17K{\cdot}m^2/GW$ at 300K. The simulation result was experimentally confirmed by the time-domain thermoreflectance technique. A 90nm thick Al film was deposited on a Si(100) wafer using an e-beam evaporator and the TBR on the film/substrate interface was measured using the time-domain thermoreflectance technique based on a femtosecond laser system. A numerical solution of the transient heat conduction equation was obtained using the finite difference method to estimate the TBR value. Experimental results were compared to the prediction and discussions on the nanoscale thermal transport phenomena were made.

Annealing Effects on VOx Thin Film Deposited by DC Magnetron Sputtering Method

  • Park, Il-Mong;Han, Myeong-Su;Han, Seok-Man;Go, Hang-Ju;Kim, Hyo-Jin;Sin, Jae-Cheol;O, Tae-Seung;Kim, Dong-Il
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.08a
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    • pp.223-223
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    • 2011
  • 적외선 감지기로 사용되는 microbolometer 소자재료로 VOx 또는 비정질 Si이 가장 많이 사용된다. 그 중에서 VOx 물질은 온도저항계수 즉, TCR이 높고 감지도가 우수하기 때문에 비냉각 적외선 검출기에 많이 응용된다. Microbolometer 검출기는 그 응답도는 micromachining 공정에 의해 좌우되는 열 고립구조에 의해 좌우된다. 특히 TCR 값이 크고, 열시상수 값이 작을수록 양질의 감지도를 얻을 수 있으므로 재료의 선택 및 공정이 매우 중요하다. 따라서 본 연구에서는 비냉각 적외선 감지소자로 사용되는 VOx 박막을 DC Sputtering을 사용하여 증착하였으며, 그 특성을 조사하였다. MEMS 공정에 의한 센서의 제작은 적외선을 흡수하여 저항변화를 읽어내어 판독하는 Readout IC(ROIC) 위에 행해진다. Monolithic 공정에 의해 이러한 ROIC 위에서 공정이 동시에 행해지므로 공정온도는 매우 중요한 요소로 작용한다. 따라서 증착된 VOx 박막의 열처리 효과를 연구하였다. 열처리 온도는 $250^{\circ}{\sim}420^{\circ}C$, 열처리 시간은 20~80 min 까지 변화시켰다. 갓 증착된 VOx 박막의 저항은 약 200 $k{\Omega}$이였으며, TCR은 -1.5%/$^{\circ}C$로 나타났다. 열처리 온도가 증가함에 따라 TCR 값은 증가하였으며, 열처리 시간이 증가할수록 역시 TCR 값이 증가하는 경향을 보였다. 열처리 온도 320$^{\circ}C$, 열처리 시간 40 min에서 TCR 값은 약 -2%/$^{\circ}C$의 값을 얻을 수 있었다. 이러한 성능의 VOx 박막을 이용하여 비냉각형 microbolometer 검출소자를 열변형없이 공정을 수행할 수 있을 것으로 기대한다.

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Temperature Properties about SMD Inductor Core of Union Type (일체형 SMD Inductor 코어에 대한 온도 특성)

  • Kim, Ki-Joon
    • 전자공학회논문지 IE
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    • v.47 no.2
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    • pp.32-37
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    • 2010
  • In this study, to develop union type SMD inductor core needs to have the desire of super miniaturization and high reliability, it analyzed temperature properties due to electric power value. As the temperature of electronic parts rise, it bring to technical obstacles that parts can not normal operation, it reduce the span of life to raise the fault ratio. Also, it impact to the parts by heat change power and expansive power, it can not behave exactly, and it have an effect on reliability. It measured the difference value between conditional temperature and parts temperature to union type SMD inductor core. As the results of simulation using D.C. current and resistor($R_dc$), it obtained the excellent regular current values at rising temperature of 40[$^{\circ}C$].

A Study on the Economical Design of Airport Low-Voltage Feeder Which is considering the Temperature Character (온도특성을 고려한 공항 저압간선의 경제적인 설계기법에 관한 연구)

  • 최홍규;조계술;송영주
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.17 no.3
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    • pp.119-126
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    • 2003
  • The size of low voltage level conductor cables can be installed with a long length just like a aviation field, shall be determined for considering the ampacity of cable and the drop of voltage for the power system. Therefore, The size of the conductor cables may be larger one for considering the tolerable voltage drop comparatively, although the allowable ampacity of the conductor cables may have a margin in comparison with the rated full load current In this case, the conductor cables' allowable ampacity will be very larger than the rated full load current and the generated heat of the conductor will be relatively downed. The conductor cables' alternating current resistance corrected with the maximum allowable temperature of the conductors, has been applied on the general formula for the calculating the voltage drop in determinating the size of low voltage level conductor cables, and the resistance is larger than the resistance corrected with the actual temperature of the conductor cables. This paper was studied for the purpose of the conductor resistance corrected with the actual temperature rise of the conductor and address the economic design formula so that this studies shall minimize the errors which can be occurred in comparison with the general formula and which can be applied in design work for determining the size of low voltage level conductor cables.