• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2016년도 춘계 학술논문 발표대회
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• pp.107-108
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• 2016

When the construction in a low temperature, the concrete performance is deteriorated by frost damage at early age. In this study, the form utilizing heating sheet and insulation is measured the performance to prevent frost damage at 10 below zero. It produced five types of the form and to measure the temperature history and compressive strength. At first, form attached heating sheet showed the highest temperature. But the form attached vacuum insulation showed the highest temperature ever since 12hours. In the case of compressive strength, the form attached heating sheet + isopink(polystyrene foam board) showed the highest compressive strength. It was followed by vacuum insulation. As a result, the form utilizing insulation and heating sheet helped to prevent frost damage.

• 한국구조물진단유지관리공학회 논문집
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• 제21권4호
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• pp.132-139
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• 2017

본 연구에서는 저온환경에서 콘크리트 동해를 방지하기 위해 생석회의 화학반응을 활용한 발열시트 및 단열재를 사용하여 제작한 거푸집 특성을 실험을 통해 평가하였다. $-10^{\circ}C$ 정온조건에서 거푸집 실험 결과, 발열시트가 부착된 거푸집의 경우 발열시트 내부 생석회의 발열로 인해 타설 초기에 일반거푸집에 비해 $10^{\circ}C$이상 높은 온도이력을 보여주었고 단열재를 부착한 거푸집의 경우 콘크리트 수화열을 보존하여 지속적으로 높은 온도를 유지하는 특징을 나타냈다. 아이소핑크와 발열시트를 부착한 거푸집과 진공단열재를 붙인 거푸집이 압축강도나 적산온도에서 가장 높은 값을 가졌다. 압축강도 측정시 진공단열재 및 아이소핑크와 발열시트를 부착한 거푸집이 재령 3일에서 약 5 MPa로 가장 높게 측정되었다. 몽골 현지 외기온도에서도 실험을 하였는데 앞선 결과와 마찬가지로 발열시트, 단열재를 함께 붙인 거푸집이 48시간 동안 $25^{\circ}C$ 이상으로 가장 높은 온도이력를 나타내었다. 따라서 거푸집에 발열시트 및 단열재 부착을 함으로써 발열 및 단열효과로 인해 저온환경에서 콘크리트 강도발현에 도움을 주는 것을 확인할 수 있었다.

• 한국환경과학회지
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• 제7권2호
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• pp.233-241
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• 1998

This study Is concerned with properties of a thermal convection in a stably stratified Boussinesq fluid caused by partial heating at the lower boundary. For thins purpose, two-dimensional, nonrotating system was employed. U the heating is very strong, convection takes the form of a turbulent plume. Othenuse, remains laminar. If the partial heating at the bottom boundary Is symmetric. the convection takes the form of a trubuient plume. Otherwise remains but beating form Is not so signiacant as to alter the vergence in the lower layer at the center of the partial heating area. The temperature perturbation is characterized by the temperature 'Cross-Over' over the partial heating area. These features are cleared ac- cording to the Increase of temperature difference between the center and side part of the bottom boundary.

• 한국세라믹학회지
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• 제55권5호
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• pp.440-445
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• 2018

To control the electrical properties of a SiC heating element, we sintered $SiC-ZrB_2$composites by using the spark plasma sintering method. The addition of $ZrB_2$ particles with lower electrical conductivity to the SiC matrices with comparatively higher electrical resistivity lowers the electrical resistivities of the composite material. The $ZrB_2$ particles aggregate to form large particles and 3-1, 3-2, and 3-3 networks, i.e., conduction paths. In our study, about $1-{\mu}m$-sized $ZrB_2$ powders start to form the conduction path at about 10 vol.% of addition, namely the threshold volume. The Joule heating experiment shows that 20 vol.% $ZrB_2$-added SiC heating element has outstanding heating efficiency.

• 한국철도학회논문집
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• 제17권5호
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• pp.365-372
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• 2014

콘크리트 공사에서 공기단축과 시공비 절감을 위하여 가장 핵심적인 기술 중 하나는 온도 제어 양생기술이다. 최근에 마이크로웨이브를 이용한 발열 촉진 양생방법이 개발되었다. 본 연구에서는 개발된 기술을 적용한 콘크리트의 조기 강도발현특성을 실험적으로 고찰하였다. 총 6차에 걸친 대형 Mock-up 실험을 수행하였으며 실험결과를 성숙도이론에 근거하여 해석하였다. 개발된 방법으로 양생된 콘크리트의 압축강도 발현과 성숙도는 로그함수의 관계를 나타내었으며, 일반적인 고온 증기 양생된 콘크리트에 적용되는 등가재령이론으로 강도예측이 가능한 것으로 확인되었다. 개발된 마이크로웨이브 발열거푸집에 의해 동절기에도 하루면 거푸집 탈형을 위한 소요강도를 확보할 수 있는 것으로 나타났다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.153-154
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• 2019

This study is a mock-up experiment prior to field application of insulated gang form. In order to investigate concrete Heating cost in winter, pre-comparison was made before application.

• 한국태양에너지학회 논문집
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• 제32권2호
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• pp.19-27
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• 2012

This paper describes an experimental study on efficiency of solar collector in solar water heating system connected to hourly water heating load. In general, the functional form of solar efficiency is expressed as a function of fluid temperature entering solar collector, ambient temperature, and solar irradiance. When energy saving from solar heating of water heating system is analyzed on along-term basis such as one year with given solar irradiance data, simplified analysis is more convenient han detailed system simulation for quick assessment. However, the functional form of the efficiency is not convenient for approximately simplified energy analysis because the inlet temperature can be obtained through a detailed system simulation. In the study, solar collector efficiency is obtained with various daily water heating load sand daily solar irradiance using experimental tests. The study also considers large residential buildings such as apartment buildings for application of solar water heating systems. From test results, it is found that daily solar collector efficiency is proportional to daily water heating loads and daily solar irradiance. The data obtained from the study can be utilized to find a functional relation between daily solar irradiance and daily heating load in stead of collector inlet temperature for application of solar collector efficiency to long-term approximated energy analysis of solar heating system.

• 동력기계공학회지
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• 제18권1호
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• pp.45-50
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• 2014

This study focuses on the analysis of the cooling and heating load in accordance with apartment houses arrangement type using Ecotect Analysis. Korea have to reduce energy consumption part of building except in industry and transport because the rate of dependence on imports amounts to 94%, Apartment houses built in various forms in order to reduce energy are modelled in each window area ratio, shape, orientation, and climate through simulation. Through this study, we can analyze the cooling and heating load by form, window area ratio, orientation, and climate change and know the optimal elements by the form. In particular, although there have been done research on the window area ratio and the arrangement form, the research of the regional climate characteristics and the direction are hardly carried out. To supplement those problem, adding to seven direction and climatic element of southern region is characteristic(L Type, Y Type, - Type) of this study. The form of apartment houses built 10 years ago is modelled for simulation.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.17-22
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• 2007

Global average temperature rise accelerates by global warming in the three decades of the 20th century. But now we use heating degree days which was established 20 years ago. Therefore new heating degree days for 15 district areas of korea was determined using long-term measured data. Five different base temperatures ranging from 24 to $16^{\circ}C$ were chosen in the calculation of heating degree days. And yearly heating degree days were given in the tabular form.

• 한국환경과학회지
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• 제7권3호
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• pp.349-360
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• 1998

Effects of uniform flow on a two-dimensional mesoscale horizontal convection were investigated by using the vorticity and thermodynamic equations. For thins purpose, We simulated properties of a thermal convection m a stably stratified Boussinesq flued caused by partial heating at the center of a lower boundary If we don't consider effects of the uniform flow, the convection takes the form of aidsymmetrlc with respect to the z-alds. But when uniform flow Is strong, velocity field and temperature field consist of a sin91e cell structure which spreads upstream side of the partial heating area. The flow pattern for strong uniform flows takes the form of positive temperatue near the ground and negative temperature perturbation soft over the partial heating area, and downward motion directly over the upwind portion of the partial heating area and upward motion on the downstream side. The downstream edge of the upstream cell Is shifted in the downstream direction with the Increase of uniform flow almost linearly.