• Title/Summary/Keyword: Heat Insulator

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Magnetonic Resistance Properties of Semiconductor Thin Films by Plasmon Effect on Fabricated Si(100) Substrate (플라즈몬 효과에 의한 실리콘 기판위에 증착된 반도체 박막의 자기저항특성)

  • Oh, Teresa
    • Journal of the Semiconductor & Display Technology
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    • v.18 no.3
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    • pp.105-109
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    • 2019
  • Plasmons have conductive properties using the effect of amplifying magnetic and electric fields around metal particles. The collective movement of free electrons in metal particles induces and produces the generation of plasmon. Because the plasmon is concentrated on the surface of the nanoparticles, it is also called the surface plasmon. The polarizing effect of plasma on the surface is similar to the principle of surface currents occurring in insulators. In this study, it was found the conditions under which plasma is produced in SiOC insulators and studied the electrical properties of SiOC insulators that are improved in conductivity by plasmons. Due to the heat treatment temperature of thin film, plasma formation was shown differently, metal particles were used with normal aluminium, SiOC thin films were treated with heat at 60 degrees, conductivity was improved dramatically, and heat treatment at higher temperatures was found to be less conductivity.

Study on Long-term Deterioration Properties of Porcelain Insulators with Aluminous System (알루미나계 자기애자의 장기 피로특성에 관한 연구)

  • Han, Se-Won;Cho, Han-Goo;Lee, Dong-Il;Cho, In-Hyuk
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.07a
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    • pp.562-563
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    • 2005
  • In case of aged porcelain, the failure in basic performance tests happened in cool-heat tests. Based on this characteristic, we studied the method predicting failure phenomena through more severe accelerated cool-heat ageing and accelerating thermal mechanical performance tests. Test results indicated that the thermal stress by temperature gradient was more severe parameter than thermal stress by quenching cycles within a category of standard or accelerating methods. And there is no the deterioration of statistic strength, but the deterioration of strength according to accelerating tests is serious.

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Heat Transfer Analysis for Optimum Design of a Thermoelectric Cooler (열전 냉각기의 최적 설계를 위한 열전달 해석)

  • 김제익;박찬형;강용태;최창균
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.15 no.11
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    • pp.889-894
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    • 2003
  • The objectives of this study are to present a proper mathematical model for a thermoelectric cooler equipped with the spacer and to investigate the effect of its geometries by heat transfer analysis. In order to enhance the efficiency of the thermoelectric cooler, the spacer is inserted between TEM (thermoelectric module) and cold plate. The theoretical results show that the COP (coefficient of performance) increases nonlinearly as high as 0.63 with increasing the depth of spacer and the depth of TEM and with decreasing the area of insulator.

Changes in Temperature during Storage of Lunch-Box and Effects of the Heat Insulator Use on the Lunch-Box Freshness (도시락 보관중 온도변화와 신선도 유지를 위한 단열재 사용효과)

  • Kim, Joong-Man;Chun, Chong-Nam
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.16 no.4
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    • pp.343-349
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    • 1987
  • This study was executed to investigate proper storage conditions for freshness of lunch-box and prevention of lunch-box borne illness. When boiled rice was put into the empty lunch-box without cooling, temperature of the lunch-box was $70^{\circ}C$ to be able to destroy vegetative cell of microoganism in the lunch-box. Temperature of the side-dish canister that is placed on the hot lunch-box was increased from $15^{\circ}C$ to $53^{\circ}C$. The use of the insulator(one to two layer) between the lunch-box and side-dish canister was effective in insulation of the heat that is conducted from the hot lunch-box to the side-dish canister. The insulation layer(asbestos) was also effective to inhibit the decrease of pH value and growth of microoganisms in the toiled rice and side-dish during storage of the lunch-box. The number of microoganisms in the lunch-box covered without cooling was less than in the case of lunch-box covered after cooling; however, the amount of generation in condensed water that is responsible for swelling of boiled rice in the lunch-box occurred much more in the one than in the other, and was a little generated in the case of high temperature storage, insulator use, and when covering the lunch-box after cooling, and pre-evaporation by stirring boiled rice in the cooking pot before filling it. In addition, inserting the heat insulators on and bottom of the lunch-box the boiled rice can be eaten without coldness in winter season.

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A Study on Effect of Scale Formation in Water Jacket on Thermal Durability in LPG Engine (엔진 물통로 내부 벽면 스케일 축적이 LPG 엔진의 열적 내구성에 미치는 영향에 대한 연구)

  • 류택용;신승용;최재권
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.3
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    • pp.42-50
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    • 2001
  • In this paper, the effects of scale formation in engine water jacket upon the thermal durability of engine itself and its component parts were studied. To understand the effect of quality of water, a full load engine endurance test for 50 hours was carried out with not-treated underground water. The followings were found through the tested engine inspection after the endurance test; 1-2 mm thick scale formation in the engine water jacket, valve seat wear, piston top land scuffing, piston pin stick, and cylinder bore scuffing in siamese area. In order to understand the causes of above test results, the heat rejection rate to coolant, the metal surface temperature of combustion chamber, and the oil and exhaust gas temperatures were measured and analyzed. The scale formed in the engine water jacket played a role as thermal insulator. The scale formed in the engine reduced the heat rejection rate to coolant and it caused to increase the metal surface temperature. The reduced heat rejection rate to coolant increased the heat rejection rate to oil and exhaust gas and increased the oil and exhaust gas temperature. Also, the reasons of valve seat wear, piston top land scuffing and cylinder bore scuffing, and piston pin stick quantitatively analyzed in this paper.

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Organic Thin Film-Transistor using Pentacene

  • Kim, Seong-Hyun;Hwang, Do-Hoon;Park, Heuk;Chu, Hye-Young;Lee, Jeong-Ik;Do, Lee-Mi;Zyung, Tae-Hyoung
    • 한국정보디스플레이학회:학술대회논문집
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    • 2000.01a
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    • pp.215-216
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    • 2000
  • We fabricated the thin-film transistors using organic semiconductor, pentacene, on $SiN_x$, gate insulator. X-ray diffraction experiments were performed for the sample after heat-treatments at higher temperatures. We confirmed that we obtained "thin-film phase" from the condition used here. From the electrical measurements, we also confirmed that no charges are accumulated at the interface between organic and insulating layer, and FET characteristics of the organic FET using pentacene was discussed.

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Research of Flow Electrification Phenomena of the used Environment-Friendly Vegetable Insulating Oils (친환경 식물성절연유의 유동대전현상 연구)

  • Choi, Sun-Ho;Huh, Chang-Su
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.4
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    • pp.580-584
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    • 2012
  • The insulating oils perform a cooling and insulation action in electric power transformer. The mineral oil has immanent fire dangerousness and environmental contamination problem. Vegetable insulating oil has higher ignition point, flash point and more excellent biodegradability than conventional mineral oil. In a real oil-filled transformers, some of the power is dissipated in the form of heat. And transformer require the heat to be removed from the winding and insulator by forced convection of the insulating oil. The flow electrification occurs when insulating oil was forced to be circulated. In this paper, influence of temperature, velocity of flow, and insulating pipe and diameter on streaming electrification of vegetable insulating oil was investigated using forced circulation apparatus. Temperature effects were most significant, and it showed a peak in the temperature $30^{\circ}C$ to $35^{\circ}C$ at insulating and copper pipe. The change of flow electrification according to area variety could be checked by change of diameter.

Calculation of Heat Loads and Temperature Distribution for the HTS Termination Current Lead (HTS 단말 전류도입선 형상에 대한 온도분포 및 열부하 계산)

  • 조승연;사정우;김도형;김동락;김승현;양형석
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • 2003.02a
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    • pp.36-39
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    • 2003
  • HTS (High Temperature Superconducting) cable termination current lead has been designed based on simplified boundary conditions such as fixed temperature at both end and sdiabatic/convection in the side wall. However, in the real situation the current lead is enclosed with insulators and exposed to insulation oil and L$N_2$. Therefore it is necessary to consider them for the proper current lead design. In this paper, several important design parameters were chosen and their effect on the temperature distribution and heat loads on the current lead has been investigated. It was found that current lead has to be 2 stage to reach the minimum temperature requirement of insulation oil and insulator is required to reduce the cooling capacity of cryogenic system.

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Deflection Characteristics of Permanent Formwork Using Multi-layer Insulation (다층형 단열재를 사용한 영구거푸집의 처짐 특성)

  • Ryu, Hwa-Sung;Shin, Sang-Heon;Song, Sung-Yong;Kim, Deuck Mo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2019.11a
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    • pp.130-131
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    • 2019
  • As part of recent low-energy policies, thermal insulation standards for buildings are being tightened every year. In addition, the conventional styrofoam insulating material has a problem that the thickness of the heat insulating material to achieve a standard heat permeability is rapidly increased. Due to the thick insulation, there is a high risk of spreading vulnerable structures such as fire due to lack of space between buildings. On the other hand, the method of using the insulation as a formwork is known to be excellent cost saving effect through the reduction of the formwork usage and the simplification of the external insulation work. In order to solve this problem, this study aims to fabricate a multi-layered insulator that combines high-performance phenolic foam insulation and styrofoam insulation and evaluate the deflection characteristics for use as formwork.

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Effect of Waste Glass Wool on Mechanical Properties of Concrete (폐글라스울이 콘크리트의 역학적 특성에 미치는 영향)

  • Kim, Jeong-Tae;Choi, Woo-Hyuk;Chung, Chul-Woo;Lee, Jae-Yong
    • Journal of the Korea Institute of Building Construction
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    • v.16 no.2
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    • pp.117-123
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    • 2016
  • Glass wool is a material that has been used as a heat insulator in various fields including construction industry. Since it is a nonflammable material, it does not generate toxic gases on fire, and thus public agencies recommend using glass wool as a heat insulator instead of other organic materials. However, repeated drying and wetting cycles can deteriorate thermal property of glass wool due to the shrinkage and reduction in pore size. For this reason, it needs to be replaced periodically, and waste materials are generated. This research aims to utilize waste glass wool as additives for increasing mechanical properties of concrete. According to the experimental results, it was found that glass wool has weak pozzolanic activity, and beneficial effect on both compressive and flexural strength. The optimum amount found in this experimental work was 0.5% volumetric addition to the concrete.