The annual energy demand of the standard rural house models Nongrim-10-26 -ga was analyzed using the DesignBuilder. Size of window and type of window were selected as simulation parameters. As a result, heating energy demand was 8.3 times higher than cooling energy demand and reducing heating energy demand is important factor in reducing total building energy. When increasing window glazing size, internal heat gain and loss was changed depending on the outdoor weather conditions. Cooling energy demand increases in summer and heating energy demand increases in winter. When the type of window was changed, cooling energy demand was decreased as the SHGC value was decreased. However, heating energy demand was changed depending on both of the SHGC value and U-value of the selected window type.

In this paper, the PEMFC performance was studied using three dimensional numerical analysis. The effect of GDL porosity and cathode inlet humidity on the cell polarization curve was analyzed. The GDL porosity of 0.3, 0.5, 0.7 and cathode inlet humidity of 20, 40, 60, 80, 100 percent were selected as simulation cases while the anode inlet humidity was maintained as 100 percent. For a constant cell voltage condition, the highest current density was obtained at GDL porosity of 0.7 and cathode inlet humidity of 20 percent. As GDL porosity increases, the amount of hydrogen diffusion to membrane from the anode increases and chemical reaction also increases. As cathode inlet humidity decreases, oxygen mass fraction of cathode gas channel increases and chemical reaction also increases.

This study is on the performance characteristics of bubble pump with vertical pipe of different lengths. For the experimental facilities composed of electrical heater used for providing heat source to generate bubble, a vertical tube with Ø4mm diameter, length of 200mm, 300mm, 400mm and 500mm. Storage tank with capacity was of 40 L containing a heat exchanger. The separator and condenser of the air bubble pump were installed separately. The results obtained from this experiment are as follows: there were a few variations of values of temperatures according to vertical pipe lengths of the bubble pump. The mass flow rate was increased by 0.17g/s when it was short as 200㎜ long pipe. But when vertical pipe length was 500㎜, it reached the normal temperature quickly because the slug flow occurred in this case at initial stage. Consequently, it was found that 500㎜ of the vertical pipe length was optimum for best performance of bubble pump.

Fe(C) nanocapsules were prepared by the chemical vapor condensation(CVC) process using the pyrolysis of iron Their characterizations were studied by means of X-ray diffraction, X-ray photoelectron spectrometer and transmission electron microscopy. The long-chained Fe(C) nanocapsules hav-ing the mean size of under 70 nm could be obtained below in different gas flow rates. The particle size of the powders was increased with increasing decomposition temperature, but it was decreased with increasing CO gas flow rate. The Fe powders produced at consisted of three layers of phases, but it had two phase core-shell structure which consited of phase of core and graphite of shell at

Ni0.5-Zn0.4-X0.1·Fe2O4의 조성에서 X를 각각 Cu, Mg, Mn으로 치환시켜 치환원소에 따른 결정구조와 형상, 입도 및 자기적 성질을 비교 분석하여고, Network Analyzer을 이용하여 Ni0.5-Zn0.4-X0.1·Fe2O4-Rubber Composite의 재료정수 및 전파흡수특성에 대하여 비교 조사하였다. 치환원소에 관계없이 동일한 결정구조와 형상 및 입도를 나타냈고, VSM 분석결과 치환원소에 관계없이 동일한 자화값을 가지며, Mg로 치환된 경우 가장 큰 보자력과 자기이력손실을 나타냈다. 또한 Mn으로 치환된 경우 가장 높은 유전손실(εr"/εr')을, Cu로 치환된 경우에는 가장 큰 자기손실(μr"/μr')을 나타냈다. 4mm의 두께로 제조한 Compos-Composite에서는 Mg로 치환된 시료가 2GHz에서 -40dB이상의 가장 우수한 전파흡수특성을 나타내었다.

In-Sit반응소결에의해 Si과 AI금속분말을 이용하여 Si3N4-AIN 복합세라믹스를 합성하였다. 합성된 Si3N4-AIN복합세라믹스의 미세조직과 결정구조를 해석하기 위해, OM, TEM, XRD및 EDX를 이용하였으며, Si3N4-AIN -20wt.%AIN복합세라믹스에서 Si의 질화율은 97%로 가장 높았다. Si3N4-AIN 복합세라믹스에서 Si의 질화율은 AI첨가량 증가에 따라 감소하였다. 대부분의 AI입자들은 다결정 AI입자들은 다결정 AIN(4-H구조)로 완전질화되었으며, 따라서 잔류 AI상은 반응소결체내에서 관찰되지 않았다. Si3N4의 결정구조는 α와 β구조가 혼재된 상태이며, 잔류 Si입자내에서는 미소균열 및 전위가 관찰되었다. AI/Si3N4와 Si3N4 두계면에서 이들은 거친 형상을 보이지만, 계면반응상은 관찰되지 않았다.

본 연구에서는 굵은 골재 특성이 콘크리트 건조수축에 미치는 영향을 평가하기 위하여 높은 밀도를 가진 전기로 산화슬래그를 굵은 골재로 사용하여 콘크리트 건조수축 시험을 진행하였다. 실험 결과, 전기로 산화슬래그를 굵은 골재로 적용한 콘크리트의 경우 일반 골재를 사용한 콘크리트에 비해 건조수축 발생량이 저감되었으며, 이는 일반 골재에 비해 높은 밀도를 가진 전기로 산화슬래그의 물리적 특성에 기인한 것으로 사료된다.

본 연구에서는 고 흡수성 폴리머의 입자형태와 혼입율에 따른 모르타르의 강도 특성을 조사하였다. 고 흡수성 폴리머의 수분 흡수·방출에 의한 내부양생 효과 검증을 위해 수중양생과 기중양생을 실시하여 강도 특성을 비교하였다. 실험결과에 따르면, 수중양생의 경우 입자형태와 혼입율에 따라 큰 차이를 나타내지 않았다. 그러나 기중양생의 경우 입자크기가 큰 고 흡수성 폴리머가 내부양생 효과로 인해 더 높은 강도 값을 나타내었다. 모르타르의 공극구조 분석을 통해 강도와의 상관관계에 대한 추가적인 분석이 필요하다.

본 연구에서는 고 흡수성 폴리머를 혼입한 콘크리트의 기초 물성을 평가하였다. 또한 콘크리트 내부의 SAP의 내부양생 효과를 확인하기 위해 표준양생과 봉함양생을 실시하였다. 실험결과, SAP의 혼입률이 증가함에 따라 슬럼프 감소율이 증가하였으며, 표면전기저항도 증가하였다. 재령 7일과 28일의 압축강도 측정결과, 표준양생을 실시한 경우 압축강도의 증감이 SAP의 종류와 혼입률에 관계없는 것으로 나타났으며, 봉함양생을 실시한 경우 SAP 혼입률에 따라 강도가 증가하였다.

In this study, they were evaluated that the fundamental properties of mortar using a superabsorbent polymer. From the results, the flow value tends to decrease as the SAP content increases, and the compressive strength shows no particular tendency. This is due to the difference in SAP absorption rate. Therefore, it is necessary to accurately measure the absorption rate depending on the type of SAP, and it is considered that addition of water should be depending on the absorption rate.

In this study, the compressive strength and elastic modulus of concrete mixed with electric furnace slag were evaluated. The concrete specimens were prepared using the steel slag as coarse aggregate and heavyweight waste glass as fine aggregate. From the results, compressive strength and the elastic modulus were improved with the addition of electric furnace slag.