• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 가을 학술발표회 논문집
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• pp.329-333
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• 1995

The usual methods for the temperature control of mass-concrete structures include the use of low-heat cement, pre-cooling, or pipe-cooling. In order to control the heat of hydration of mass-concrete structures such as massive pier or anchor block, and mat foundation, the pipe cooling method is widely acceptable for pratical use. In this paper, method of analysis using the Finite Element Method was applied to analyze the heat exchange on the field of three dimensional thermal conduction. The result of analysis Well agreed with experimentally measurement data by "KUMATANI". The method of this analysis will be used widely to control the heat of hydration by the pipe cooling in mass-concrete.-concrete.

• 한국항해항만학회지
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• 제31권10호
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• pp.879-884
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• 2007

진공예냉장치에서 상대습도변화 및 냉각온도변화에 따른 야채류의 온도변화에 대하여 고찰한 논문이다. 실험장치는 진공챔버, 이젝트펌프, 냉동기장치, 계측장치 및 냉각수 계통으로 구성되어 있다. 실험결과 야채류의 냉각속도는 야채류의 함수율에 크게 의존하고 있으며, 함수율이 높은 야채가 낮은 야채에 비하여 냉각속도가 증가하는 것을 알 수 있다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.127-130
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• 2007

Effect of the forging process parameters on the void crushing is the cogging process has been studied in order to find the most effective factor. The Process parameters used for this study are die width ratio, reduction ratio and pre-cooling time before cogging process. Void crushing analysis about the selected process parameters was carried out using FE analysis. The results of FE analysis were evaluated by Taguchi method. It was found that the efficiency of void crushing increases with an increase in the values of all selected process parameters and the principal factor controlling the void crushing was identified as the reduction ratio.

• 소성∙가공
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• 제16권7호
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• pp.502-508
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• 2007

Effect of the process parameters of the cogging process on the void crushing has been studied in order to identify the most effective factor. The process parameters considered in this study are die width ratio, reduction ratio and pre-cooling time before cogging process. Void crushing analysis with the selected process parameters was carried out using FE analysis. The results of FE analysis were evaluated by Taguchi method. It was found that the efficiency of void crushing increases with an increase in the values of all selected process parameters and the principal factor controlling the void crushing was identified as the reduction ratio.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.561-564
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• 2009

This study is to examine the possibility of pre-cooling at platform. Through measurement of the thermal environment of Bujeon Subway platforms, review the potential use of ground-water and night purge. The results of this research can improve the thermal environment pre-cooling of the design.

• 천문학회지
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• 제40권4호
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• pp.161-164
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• 2007

We calculate the evolution of multiple supernova (SN) explosions inside a pre-exiting bubble blown up by winds from massive stars, using one-dimensional hydrodynamic simulations including radiative cooling and thermal conduction effects. First, the development of the wind bubble driven by collective winds from multiple stars during the main sequence is calculated. Then multiple SN explosion is loaded at the center of the bubble and the evolution of the SN remnant is followed for $10^6$ years. We find the size and mass of the SN-driven shell depend on the structure of the pre-existing wind bubble as well as the total SN explosion energy. Most of the explosion energy is lost via radiative cooling, while about 10% remains as kinetic energy and less than 10% as thermal energy of the expanding bubble shell. Thus the photoionization and heating by diffuse radiation emitted by the shock heated gas is the most dominant form of SN feedback into the surrounding interstellar medium.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 봄 학술발표회 논문집
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• pp.263-267
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• 1995

The usual methods for the temperature control of mass-concrete structures include the use of low-heat cement, pre-cooling, post-cooling, or sheet curing. In order to control the heat of hydration during the construction of mass-concrete structures, the combination of the above methods is commonly employed. For the construction of mass-concrete structures such as massive pier or anchor, it is necessary to control the curing temperature with pipe cooling. In this study, the method of analysis on the effect of pipe of was proposed to prevent the thermal cracking due to heat of hydration In addition the effect of covering the concrete surface with blanket insulation was investigated. The results of the present study may be useful for the prediction of curing temperature of mass-concrete structures and the reasonable construction management.

• 한국기계가공학회지
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• 제16권2호
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• pp.142-148
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• 2017

The objective of this study is to investigate the cooling characteristics of a heat sink for an LED headlight used in passenger cars. To this end, this study conducts the experimental and numerical analysis of the heat sink heated at constant heat fluxes without air flow applied. In the experiments, heat was transferred at a constant heat flux through the bottom of a heat sink. The measured temperature on pre-selected locations of the heat sink was in good agreement with the numerically predicted one. The experimental and numerical results indicate that the convective heat transfer coefficient for the natural convection mode was decreased by increasing the heat flux applied to the bottom of heat sink, lowering the cooling capabilities.

• 한국산림과학회지
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• 제104권4호
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• pp.558-563
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• 2015

'미풍' 밤의 수확 후 전처리 방법(수냉식 예냉, 수냉식 예냉+오존, 수냉식 예냉+마이크로버블, 수냉식 예냉+오존+마이크로버블)이 저장 중 품질에 미치는 영향을 조사하였다. 밤 과실의 품질변화는 세척 처리보다 수냉식 예냉처리의 효과가 더 크게 나타났다. 하지만 부패율과 미생물 수에서는 처리구간 차이가 확연히 나타났다. 부패율은 저장 12주 후 무처리구가 20.0%로 가장 높았고 수냉식 예냉+오존 처리구와 수냉식 예냉+오존+마이크로버블 처리구가 3.3%로 가장 낮게 나타났다. 미생물 수는 세척처리 직후 무처리구(4.4 log CFU/g) > 수냉식 예냉 처리구(4.0 log CFU/g) > 수냉식 예냉+오존+마이크로버블 처리구(3.5 log CFU/g) > 수냉식 예냉+오존 처리구(3.4 log CFU/g) > 수냉식 예냉+마이클로버블 처리구(3.3 log CFU/g)순으로 차이가 나타났으며 저장 12주 후에는 4.7-5.9 log CFU/g 범위 내에서 증가하였다. 따라서 '미풍' 밤의 세척처리는 밤 과실의 부패를 경감시킴으로써 밤의 품질유지에 효과적이였고, 특히 오존처리가 밤 과실의 품질유지와 저장성에 가장 효과적이라고 판단된다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1996년도 봄 학술발표회 논문집
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• pp.264-269
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• 1996

Thermal cracks are occurred when thermal stress due to the hydration of cement exceeds the tensile strength of concrete. In this study, the thermal stresses are investigated at the massive concrete like an anchorage of suspension bridge. The thermal crack can be controlled by considering the placing height, concrete type, pre-cooling and pipe cooling in the design stage.