• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.45-51
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• 2009

A ground-loop heat exchanger in a ground source heat pump system is an important unit that determines the thermal performance of a system and its initial cost. The size and performance of this heat exchanger is highly dependent on ground thermal properties. A proper design requires certain site-specific parameters, most importantly the ground effective thermal conductivity, the borehole thermal resistance and the undisturbed ground temperature. This study was performed to investigate the effect of some parameters such as borehole lengths, various grouting materials and U-tube configurations on ground effective thermal conductivity. In this study, thermal response tests were conducted using a testing device with 9-different ground-loop heat exchangers. From the experimental results, the length of ground-loop heat exchanger affects to the effective thermal conductivity. Among the various grouting materials, the bentonite-based grout with silica sand shows the largest thermal conductivity value.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2001년도 춘계학술발표대회 논문집
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• pp.238-243
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• 2001

This paper predicted the thermal conductivity of spatially reinforced composites(SRC) by applying the volume averaging method and the thermal resistance method. The former method employs existing micro-mechanical theories and conventional transformation rules to constitute relations for the unit cells of the composites and the latter one uses the analogy between the diffusion of heat and electrical charge. To verify the theoretical prediction, the thermal conductivity of 4-D(dimensional) SRC was examined experimentally. The comparison of the numerical results with those measured by the experiment showed good agreement.

• Bulletin of the Korean Chemical Society
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• 제31권8호
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• pp.2279-2282
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• 2010

In this work, the electrical and thermal properties of polyimide/multi-walled carbon nanotube (MWNT) nanocomposites were investigated. The polyimide/MWNT nanocomposites contained from 0 to 2.0 wt % of MWNT. The electrical properties of the polyimide films were characterized by a specific resistance measurement. The thermal properties were evaluated using thermogravimetric analysis (TGA) and a differential scanning calorimeter (DSC). It was found that the thermal properties of the polyimide nanocomposites increased with increasing MWNT content and specific resistance as well. This result indicated that the crosslinking of polyimide/MWNT nanocomposites was enhanced by good distribution of the MWNT in the polyimide resins, resulting in the increase of the electrical and thermal properties of the nanocomposites.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.84-86
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• 2001

This paper deals with the characteristic and thermal analysis of brushless motors for Rack assist type Electric Power Steering(REPS). The performance of permanent magnet is under the influence of temperature. To predict the motor performance, the thermal analysis is necessary. The equivalent thermal network is composed of the thermal resistance and the temperature of major parts is calculated according to the operating condition.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2003년도 제20회 춘계학술대회 논문집
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• pp.164-167
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• 2003

열충격은 재료가 갑작스런 온도나 압력변화 혹은 급냉 조건하에 있을때 발생하는 물리적 현상이다. 본 논문에서는 레이저 조사를 이용하여 열충격 강도와 열충격 파괴인성을 평가하였다. 시험편의 온도 분포는 타입 K와 C 열전대를 이용하여 측정하였다. 조사된 표면은 SEM을 이용하여 관찰하였다. 파괴에 필요한 임계 레이저 파워가 재료의 열충격 강도와 열충격 파괴인성을 결정짓는 주요한 요소라고 할 수 있다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 봄 학술논문 발표대회
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• pp.83-84
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• 2020

In present study, we have deposited the Zinc coating using arc thermal spray and plasma arc spray processes onto the steel substrate and durability of the deposited coating was evaluated. The bond adhesion result shows that plasma arc sprayed Zn coating exhibited higher in its value compared to arc thermal spray. SEM shows that Zn coating deposited by plasma arc process is more compact, less porous and adherent compare to arc spray process. The corrosion resistance properties are evaluated in artificial ocean water solution with exposure periods. EIS results show that total impedance at 0.01 Hz of plasma arc sprayed coating is higher than arc thermal spray owing to the compact and less porous morphology. It is concluded that plasma arc sprayed Zn coating is better than arc thermal spray process.

• 한국의상디자인학회지
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• 제20권4호
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• pp.163-174
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• 2018

Consumer and property evaluation of wetsuit materials were conducted to obtain useful data for developing competitive products that meet consumer expectations and improving industrial competitiveness. Data were collected through online surveys of 213 domestic consumers who have experienced wearing wetsuit among marine leisure activities. Five types of commercial wet suit materials by brand and four types of commercial wet suit materials with the same quality by thickness were collected. Then, their physical properties, salt water resistance and thermal insulation rate were evaluated and compared. As a result, the most commonly used wetsuit material is 3 to 5 mm thick, and the basic jersey material is bonded on both sides. As a processing for imparting functionality, processing for improving warmth and reducing surface resistance are most frequently used. Consumers often feel uncomfortable when wearing a wetsuit, such as wearing comfort, weight, ease of movement, stretchability, and clothing pressure, which are different from those of casual wear. Also, mechanical strength and warmth were considered to be the most important criteria for selection of wetsuit material for purchase or rental. The mechanical properties of brand A and B were better than those of brand C, D, and E. Resilience and thermal shrinkage were better in brand C, D, and E. On the other hand, there was no significant difference in the physical properties due to the difference in thickness of the material at the same quality. Also, it was found that the thicker the material, the more stable it is in the heat. Brand A and B had superior salt water resistance than brand C, D, and E. In the thermal insulation test, brand A and B showed better insulation characteristics than brand C, D, and E, but the types of bonded fabric and surface finishing of materials were thought to have affected. In comparison of the thickness, the thicker the materials, the better the salt resistance and the thermal insulation.

• 한국재난정보학회 논문집
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• 제20권2호
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• pp.419-429
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• 2024

연구목적: 소방용 배관 보온재의 불연성능 강화와 제연덕트 보온재의 내열성능 향상을 위해 AES소재 단열재의 성능을 시험을 통해 배관보온재 및 제연덕트 보온재에 적합성을 검증하고자 한다. 연구방법: AES 단열재에 대해 불연성능과 내열성능, 단열성능을 시험을 통해 검증한다. 연구결과: '건축물 마감재료의 난연성능 및 화재 확산 방지구조 기준'에 근거하여 불연성 및 가스 유해성 시험 결과 불연성능을 확인하였고, 내화성능 표준시험 결과 내화성능도 확인하였다. 또한, 건축용 단열시험으로 단열성능도 검증하였다. 결론: 본 연구에서 AES 계열 무기질 성분 단열재에 대한 성능시험으로 불연성능, 내화성능, 단열성능이 입증됨에 따라 건축물의 화재확산 방지성능을 개선하는데 좋은 대안이 될 것으로 사료된다.

• 한국표면공학회지
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• 제30권4호
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• pp.272-280
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• 1997

The Thermal Barrier Coation(TBC) to improve the that barrier and wear resistant propenrty in high temperature ofthe aircraftength between the accumlation of the aircraft engine and the automobile engine has usually the two layer structure. One is a creamic top layer for heat insulation and the other is a metal bond layer to facilitate the bond strength between the top ceramic layer and the substrate. But, the coated layers should be peeled off because of the accumulation of the thermal stress by the differance of the thermal expantion coefficient between metal and ceramics in a hrat cyclic environment. In this study, the intermediate layer by plasm spray process was introduced to reduce the thermal stress. The powders of plasm spray coating were the Yttria Stabilized Zirconia (YSZ), the Magnesia Stabillized Zirconia(MSZ) and NiCrAlY. the intermediate layer was sprayed with the powders of the bond cast for the purpose of test were executed. The high temperature wear resistance tends to decreasnceee wear and thermal shock test were exeucuted. The high temperature were resistance of the YSZ TBC is better that of the MSZ TBC. The wearrsistance tends to decrease accoring to incresing the temperature between $400^{\circ}C$to $600^{\circ}C$. The thermal shock life of the 3 layer TBC with YSZ top casting was the most outstanding thermal shock rsisstasnce. This means that the intermediate layer should play an importnat roll to alleviate the diffrerence of the thermal expansion coef frcients between metallic layer and cermics layer.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 춘계학술대회 논문집
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• pp.209-210
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• 2009