• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 춘계학술대회 논문집
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• pp.118-126
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• 2009

The change of the thermal properties of exothermic & insulating materials with mixing condition of raw materials which is the most important factor for exothermic & insulating materials was investigated by using the evaluation system of the thermal properties of exothermic & insulating materials. In this study, the effect of the thermal properties of the exothermic & insulating materials such as exothermic properties, endothermic properties, insulating properties, maximum temperature of molten metal, ignition time of exothermic & insulating materials and temperature recovery time on the mixing ratio of reductant and oxidant, types of reductant, and particle sizes of reductants was examined. It could be expected to design the mixing condition of raw materials for various exothermic & insulating materials.

• 한국안전학회지
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• 제29권4호
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• pp.61-72
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• 2014

The aim of this study is to define the condition of optimal pre-treatment for preferable activated carbon fibers (ACFs), which are based on rayon fibers. This paper shows the ideal path of ACFs preparation process; implies that rayon fibers are pre-treated by various solvents with different times before the heating process. The pre-treated rayon fibers finally turned into desirable rayon fiber-based ACFs through optimal pre-treatment condition by heating processes. The thermal analysis method of pre-treated rayon fibers by thermo-gravimetry analyser (TGA) is an idealized tool, which analyzes the best thermal condition of pre-treatment process. Surface morphologies of resulting rayon fibers based ACFs were examined by scanning electron microscope(SEM). The results of TGA and SEM analyses show that the optimal pre-treatment condition for preparing ACFs was clearly defined, in terms of thermal stability and surface morphology.

• Composites Research
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• 제20권5호
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• pp.20-25
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• 2007

열주기법은 다공성 소재의 열확산도를 측정하는데 유용한 방법이다. 본 논문의 주 목적은 진공환경에서 다공성 소재의 열확산도 측정 시스템을 개발하고 검증하는데 있다. 이 방법을 검증하기 위하여 알루미나 시편과 폴리스티렌 폼의 열확산도를 측정하였다. 이 시편들의 열확산도는 참고값과 일치하였다. 탄소/에폭시 소재와 다공성 단열소재의 열확산도를 대기상온과 대기진공 환경에서 측정하였다. 탄소/에폭시 소재와 다공성 단열소재의 진공환경에서 열확산도는 대기환경에 비하여 각각 66.4%와 64.9% 감소하였다. 이 차이는 소재내의 기공에 있는 공기의 영향으로 추정된다.

• KIEAE Journal
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• 제17권1호
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• pp.83-89
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• 2017

Purpose: Thermal sensation or thermal comfort was randomly used in many studies which focused on combined effects of thermal and acoustic environments on human perception. However, thermal sensation and thermal comfort are not synonyms. Thermal comfort is more complex human perception on thermal environment than thermal sensation. This study aims to investigate effects of noise on thermal sensation and thermal comfort separately, and also to investigate effects of temperature on acoustic sensation and comfort. Method: Combined thermal and acoustic configurations were simulated in an indoor environmental chamber. Twenty four participants were exposed to two types of noise (fan and babble) with two noise levels (45 dBA and 60 dBA) for an hour in each thermal condition of PMV-1.53, 0.03, 1.53, 1.83, respectively. Temperature sensation, temperature preference, thermal comfort, noisiness, loudness, annoyance, acoustic comfort, indoor environmental comfort were evaluated in each combined environmental condition. Result: Noise did not affected thermal sensation, but thermal comfort significantly. Temperature had an effect on acoustic comfort significantly, but no effect on noisiness and loudness in overall data analysis. More explicit interactions between thermal condition and noise perception showed only with the noise level of 60 dBA. Impacts of both thermal comfort and acoustic comfort on the indoor environmental comfort were analyzed. In adverse thermal environments, thermal comfort had more impact than acoustic comfort on indoor environmental comfort, and in neutral thermal environments, acoustic comfort had more important than thermal comfort.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.562-566
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• 2004

Thermal shock is a physical phenomenon that occurs in the condition of the exposure of a rapidly large temperature and pressure change of in the quenching condition of material. The rocket nozzle is exposed to high temperature combustion gas, it may have failure and erosion deformation. So, it is important to select a suitable material having excellent thermal shock properties and evaluate these materials in rocket design. In this study, the temperature gradient and crack initiation of rocket nozzle material is investigated using by FEM under thermal shock condition. This is very important information in the design process of thermal structure.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2003년도 학술.기술논문발표회
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• pp.1-4
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• 2003

Recently, a structure has been larger and higher under the improvement of construction technique. So, a mass concrete constructions that a mat foundation thickness of structure is over 80cm have been many. Also, because of the reason of high strength of concrete, the matter of thermal crack have become an important task to be solved absolutely. tn a cause of a thermal crack occurrence, there are material used, mixture of concrete, construction condition and so forth. In this study, we executed temperature and stress analysis of mat foundation to know the effect of the construction condition on a thermal crack of mat foundation. And we evaluated quantitatively about the occurrence possibility of thermal crack using the hydration heat analysis program. By using of this analysis technique, we will can control skilfully the quality of a mat foundation in advance.

• 한국태양에너지학회 논문집
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• 제28권1호
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• pp.65-74
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• 2008

In this study, dynamic characteristics analysis of AC system is investigated using a cool thermal storage system. A analysing program for cool thermal storage AC system is developed. The performances are studied by several variables and dynamic characteristics. Comparing the result at conventional operation condition with that at the condition using ice storage system, this study showed the effects of the sub cooled degree, superheated degree, efficiency of compressor and evaporating temperature. At the condition using thermal storage system, the thermal storage process was operated during midnight being not needed the cooling of the AC unit through the continuous running of the condenser. The refrigerant was sub-cooled using stored energy after being discharged from the air source condenser during the daytime. The COP was increased owing to the sub-cooling of refrigerant during daytime, thus the power consumption was effectively decreased.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1998년도 추계학술대회 논문집
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• pp.77-83
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• 1998

This study is object to thermal analysis of continuous casting mold. A two-dimensional transient finite element model was developed to compute the temperature distribution and stress behavior for continuous casting mold. For thermal analysis using analysis result from FEM code. In other to thermal analysis of continuous casting mold, many variables such as casting speed, cooling condition, film coefficient, convection and load condition re considered.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
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• pp.287-292
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• 1999

This study is object to thermal analysis of continuous casting nickel-coated mold. A two-dimensional transient finite element model was developed to compute the temperature distribution and stress behavior for continuous casting nickel-coated mold. For thermal analysis using analysis result from FEM code. In other to thermal analysis of continuous casting nickel-coated mold, many variables such as casting speed, cooling condition, film coefficient, convection and load condition are considered.

• 한국생산제조학회지
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• 제8권6호
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• pp.43-49
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• 1999

This study is object to thermal analysis of continuous casting mold. A two-dimensional transient finite element model was developed to compute the temperature distribution and stress behavior for continuous casting mold. For thermal analysis using analysis result from FEM code. In order to thermal analysis of continuous casting mold, many variables such as casting speed, cooling condition, film coefficient, convection and load condition are considered.