• 대한의용생체공학회:의공학회지
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• 제29권5호
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• pp.343-347
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• 2008

Thermal conductivity, thermal diffusivity were measured in the atrium of a swine heart. Radiofrequency (RF) catheter ablation in an atrium has rapidly emerged at the treatment of symptomatic reentrant arrhythmia associated with accessory pathway or Atrioventricular (AV) node conduction. The thermal properties of an atrium are definitely necessary for these treatments because, in thermal treatments, conductivity and diffusivity are significant factors in the relationship between the applied RF power and the resulting atrium temperature rise. Thermal properties were measured using a self-heated thermistor probe. Thermistor probes were inserted into the tissue of interest and were used to supply heat within the tissue as well as to monitor the temperature rise in the tissue. The measurements were performed at temperatures of 25, 37, $50^{\circ}C$. Atrium thermal conductivity ranged from 5.17$\pm$0.12 mW/cm$^{\circ}C$ at $25^{\circ}C$ to 5.33$\pm$0.08 mW/cm$^{\circ}C$ at $37^{\circ}C$. Atrium thermal diffusivity ranged from 0.00132$\pm$0.00007$cm^2$/sec at $25^{\circ}C$ to 0.00138$\pm$0.00003 $cm^2$/sec at $50^{\circ}C$. This paper also present the thermal property comparison of both chambers of a heart (ventricle and atria).

• Journal of Welding and Joining
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• 제28권4호
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• pp.18-25
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• 2010

Super-duplex stainless steels (SDSS) have a good balance of mechanical property and corrosion resistance when they consist of approximately equal amount of austenite and ferrite. The SDSS needs to avoid the detrimental phases such as sigma(${\sigma}$), chi(${\chi}$), secondary austenite(${\gamma}2$), chromium carbide & nitride and to maintain the ratio of ferrite & austenite phase as well known. However, the effects of the subsequent weld thermal cycle were seldom experimentally studied on the micro-structural variation of weldment & pitting corrosion property. Therefore, the present study investigated the effect of the subsequent thermal cycle on the change of weld microstructure and pitting corrosion property at $40^{\circ}C$. The thermal history of root side was measured experimentally and the change of microstructure of weld root & the weight loss by pitting corrosion test were observed as a function of the thermal cycle of each weld layer. The ferrite contents of root weld were reduced with the subsequent weld thermal cycles. The pitting corrosion was occurred in the weld root region in case of the all pitted specimen & in the middle weld layer in some cases. And the weight loss by pitting corrosion was increased in proportional to the time exposed at high temperature of the root weld and also by the decrease of ferrite content. The subsequent weld thermal cycles destroy the phase balance of ferrite & austenite at the root weld. Conclusively, It is thought that as the more subsequent welds were added, the more the phase balance of ferrite & austenite was deviated from equality, therefore the pitting corrosion property was deteriorated by galvanic effect of the two phases and the increase of 2nd phases & grain boundary energy.

• 접착 및 계면
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• 제6권4호
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• pp.12-17
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• 2005

Natural fiber/phenolic biocomposites with chopped henequen fibers treated at various levels of electron beam irradiation (EBI) were made by means of a matched-die compression molding method. The interfacial property was explored in terms of interfacial shear strength measured by a single fiber microbonding test. The thermal properties were studied in terms of storage modulus, tan ${\delta}$, thermal expansion and thermal stability measured by dynamic mechanical analysis, thermomechanical analysis and thermogravimetric analysis, respectively. The result showed that the interfacial and thermal properties depend on the treatment level of EBI done to the henequen fiber surfaces. The present result also demonstrates that 10 kGy EBI is most preferable to physically modify the henequen fiber surfaces and then to improve the interfacial property of the biocomposite, supporting earlier results studied with henequen/poly (butylene succinate) and henequen/unsaturated polyester biocomposites.

• 한국건설순환자원학회논문집
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• 제8권1호
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• pp.49-55
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• 2020

본 연구에서는 바텀애시 재활용 인공토양을 적용한 옥상녹화 유니트 시스템의 표면 온도변화를 계절별로 측정하여 바텀애시 재활용 인공토양의 열특성을 분석한 결과, 바텀애시 인공경량토양이 기존 토양보다 우수한 열차단 특성이 있음을 확인하였다. 또한, 기존 옥상녹화 유니트 시스템과 개발 옥상녹화 유니트 시스템의 열차단 효과를 분석하기 위해 계절별 일교차를 측정한 결과 기존 녹화 유니트 시스템은 현장 포설형 녹화시스템보다 열차단 효과가 낮은 반면 격막을 탈거하여 바텀애시 인공경량토양을 연속된 층으로 형성하는 개발 유니트 녹화 시스템은 기존 현장 포설형 녹화시스템과 유사한 열차단 효과를 갖는 것으로 분석되었다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.1053-1055
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• 2002

Recently CRT is getting large-sized, Flatness and High Fine Pitched in the meantime the raw material for shadow mask is in rapid progress of thinness, Low Thermal Expansion and high strength.Until now we have used AK(Aluminum Killed) & Invar(Fe-Ni alloy) materials for main raw material of shadow mask component. However recently Nb and Co addition and Nb+Co addition, which has advantage of Low Thermal Expansion and High Strength. has been developed as well as applying in mass production as CRT's trend has become more flat and fine pitch. Among of them, Co addition has been mass production as forming type (Flat CRT) with the beneficial effect of low thermal expansion & high strength for the first time. Since then Nb+Co addition has been used in mass production by the request of much higher strength of shadow mask component. In case of Nb addition, It's thermal expansion coefficient is a little lower than normal Invar and a little higher than Co addition, meanwhile Its Mechanical property is almost similar to Co Addition. The used samples of this experiment are 36%Ni + Fe, 32%Ni + 5%Co + Fe, 32%Ni + 5%Co + 0.3%Nb + Fe, 32%Ni + 0.3%Nb + Fe with heat treatment temperature of 600$^{\circ}C$, 650$^{\circ}C$, 700$^{\circ}C$, 750$^{\circ}C$, 800$^{\circ}C$, 850$^{\circ}C$, 900$^{\circ}C$ respectively under the condition of 15min holding time. After heat treatment, we have observed the change of mechanical property with addition of small elements through mechanical property investigation and metal structure observation as well as transition of thermal expansion coefficient by measuring of thermal expansion coefficient at 850$^{\circ}C$. In conclusion, 5%Co addition indicates that its thermal expansion coefficient is very similar under the condition of at 850$^{\circ}C$ for 15min 's heat treatment. From the experimental result it is suggested that Co addition is mostly suitable for Doming property and Nb addition is mostly suitable for Drop property.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 춘계학술대회 논문집
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• pp.46-51
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• 2008

In this study, evaluation system of the thermal properties of the exothermic agents was investigated. Exothermic agents property evaluation system was developed by metering variation of power supply. Thermal properties of exothermic agents was affected by material mixture condition of exothermic agents, however, it was not affected by temperature. It is possible to make various exothermic agents by means of regulating thermal properties which is based on property evaluation system of exothermic agents.

• 한국추진공학회지
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• 제22권4호
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• pp.55-60
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• 2018

열적 특성은 에너지 물질 분야에서 중요한 특성 중 하나로, 분해열을 방출하기 때문에, 열적 특성 분석에 DSC(Differential Scanning Calorimetry)가 자주 사용된다. 그러나 DSC 측정의 경우, 용융과 같은 열역학적 변화가 kinetics 분석에 방해를 끼친다. 이번 연구에서는 이 문제점을 해결하는 방안으로, 등온 조건으로 한 DSC 기초 데이터와 g 단위로 측정하는 ARC(Accelerating Rate Calorimetry)의 데이터를 이용하여 AKTS(Advanced Kinetics and Technology Solutions) thermokinetic 프로그램을 이용하여 열적 노화 특성을 예측, 비교한다.

• Journal of Electrical Engineering and Technology
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• 제9권3호
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• pp.882-887
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• 2014

In this paper, the water cooling method among the forced coolant cooling methods is considered to be applied to the 110kW-class IPMSM for railway vehicles. First, basic thermal property analysis of the IPMSM is conducted using the three-dimensional thermal equivalent network method. Then, based on the results of the basic thermal property analysis, some design requirements for the water cooling jacket are deduced and a basic design of the water cooling jacket is carried out. Finally, thermal equivalent circuit of the water cooling jacket is attached to the IPMSM's 3D thermal equivalent network and then, the basic thermal and effectiveness analysis are conducted for the case of applying the water cooling jacket to the IPMSM. In the future, the thermal variation trends inside the IPMSM by the application of the water cooling jacket is expected to be quickly and easily predicted even at the design step of the railway traction motor.

• Korean Chemical Engineering Research
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• 제50권4호
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• pp.621-626
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• 2012

본 연구에서는 마이크로 기공의 중공구를 유기 고분자 수지와 복합화한 유/무기 하이브리드 물질을 제조하여 우수한 단열 성능을 갖는 코팅유리를 개발하고자 하였다. 유기 고분자 물질로는 투명성과 접착성이 우수한 6관능기의 우레탄 아크릴레이트(UP118), 3관능기의 trimethylolpropane triacrylate (TMPTA), 2관능기의 1,6-hexanediol diacrylate (HDDA), 광 개시제(Irgacure184) 등으로 구성된 자외선 경화형 수지를 사용하였다. 유리 및 실리카 중공구를 고분자 수지에 각각 10~40 vol%까지 첨가하여 얻어진 코팅 졸을 투명유리에 바(bar)코팅 방식으로 박막을 형성시킨 후 자외선 경화를 통해 최종 코팅유리를 제조하였다. 마이크로 중공구의 종류 및 함량이 제조된 코팅유리의 광 투과율, 열전도도, 접착성 및 표면 경도에 미치는 영향을 조사하였다. 복합물 코팅유리는 중공구가 과량 첨가되어도 우수한 접착성(5B)을 유지하였으며, 단열 성능은 각 중공구가 20 vol%만 함유되어도 뚜렷하게 향상된 결과를 나타냈다. 또한 실리카 중공구(SP)를 단열 재료로 사용하였을 경우 광 투과율 80 %의 투명 코팅유리를 얻을 수 있었다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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• pp.172-178
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• 2017

열적 특성은 에너지 물질 분야에서 중요한 특성 중 하나로, 에너지 물질 분해 시 분해열을 방출하기 때문에 DSC(시차 주사 열량계, Differential Scanning Calorimetry)를 자주 사용하고 있다. 승온속도를 달리한 DSC 측정의 경우, 용융과 같은 열역학적 변화로 인해 물질의 열적 측정에 방해를 준다. 또한 kg 단위로 예측하기 때문에 mg 단위 때와는 다른 공간상의 열 변화의 변수가 생긴다. 이번 연구에서는 이 문제점을 해결하는 방안으로, 등온 조건으로 한 DSC(Differential Scanning Calorimetry) 기초 데이터로 ATKS thermokinetic 프로그램을 이용하여 열적 노화 특성을 예측한다. 그리고 g 단위로 측정하는 ARC(Accelerating Rate Calorimetry)의 데이터를 이용하여 열적 노화 특성을 예측하고 결과를 비교 할 것이다.