• 한국진공학회지
• /
• 제1권1호
• /
• pp.168-175
• /
• 1992

Ion beam mixing과 질소분위기에서 Rapid Thermal Annealing을 이용하여 형성된 TiSi2 박막의 표면과 계면의 물리적, 전기적 특성이 크게 개선되었으며, 기존 Ti-SALICIDE 의 신뢰도 측면에서 문제가 될 수 있는 Oxide Spacer 상에서의 Lateral Silicide 형성이 최 대한 억제된 수 있었다. 또한 Ti-SALICIDE 공정에서의 Ti/Si와 Ti/SiO2의 Interaction을 반응 조건별로 연구하였다.

• 방사성폐기물학회지
• /
• 제11권1호
• /
• pp.11-21
• /
• 2013

현재 고준위 방사성 폐기물 심층 처분 시스템에서 기본 완충재 물질로서 건조밀도 1.6 g/$cm^3$의 경주산 칼슘 벤토나이트를 사용하고 있으나, 열전도도가 낮은 단점이 있다. 따라서 본 연구에서는 기준 완충재의 열전도율을 0.8 W/mK에서 1.0 W/mK로 향상시키기 위한 목적으로 다양한 첨가제를 다양한 혼합 방법을 통해 배합하고 열전도도를 측정하였다. 첨가제는 CNT(Cabon Nano Tube), Graphite, Alumina, CuO 및 $Fe_2O_3$ 등을 사용하였다. 혼합 방법의 경우, 핸드 믹서기를 통한 건식혼합, 습식 Milling 혼합, 건식 Ball Mill 혼합 등을 실시하였다. Ball Mill 혼합의 경우가 가장 균일하게 혼합되었기 때문에, 값의 편차가 가장 적었고 열전도도 증가율이 가장 좋았다. 지금까지 수행된 시험에서 소량의 고열전도 물질의 첨가로 경주산 칼슘 벤토나이트의 열전도도를 1.0 W/mK 수준으로 용이하게 증가시킬 수 있음을 실험적으로 확인할 수 있었다. 결론적으로, 본 연구에서 제시된 열전도 향상 방법은, 첨가제 혼합이 벤토나이트의 기본 성질인 팽윤압과 수리전도도에 미치는 영향까지 제시된다면, 국내 고준위폐기물 처분장의 개념 설계에 유용하게 활용될 수 있을 것으로 기대된다.

• 한국연소학회지
• /
• 제11권2호
• /
• pp.22-27
• /
• 2006

This experimental study has been mainly motivated to obtain generally applicable design correlation for the front mixing premix combustor. The design concept of the front mixing premix combustor is to minimize thermal $NO_x$ and prompt $NO_x$ formation by maintaining low peak flame temperature, and nearly uniform flame temperature through rapid mixing process near the ignition point. The present experimental results clearly indicate that the front mixing premix combustor yields the $NO_x$ level lower than 43 ppm $NO_x$ emissions and the nearly uniform temperature distribution.

• 설비공학논문집
• /
• 제10권2호
• /
• pp.147-154
• /
• 1998

This study was carried out for evaluating the interior thermal environment in KBS Open hall with large ceiling height and large space. Ventilation systems of KBS Open hall have combined mixing ventilation and downward displacement ventilation system. Temperature and velocity was measured 130 locations with low level(0.1m), mid level(0.6m) and high level(1.1m). But relative humidity was measured at 15 locations. The subjective thermal sensation was made an inquiry of occupancy at the location measured physical elements.

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 1996년도 추계학술발표회논문집(1)
• /
• pp.283-288
• /
• 1996

Direct safety injection into the reactor vessel downcomer annulus(DVI) is a fundamental feature of the KNGR(Korean Next Generation Reactor) four-train safety injection system. The numerical analysis of thermal mixing of ECC(Emergency Core Cooling) water through DVI with the water in the RVDC(Reactor Vessel Downcomer) annulus has been performed, in order to study the impact of nozzle location on the pressurized thermal shock and safety analysis. The results of this study show that the thermal mixing due to the natural circulation induced by the limiting accident conditions is sufficient to prevent temperature in the RVDC from dropping to the level of concern for PTS. When the DVI nozzle is located right above the cold leg, the temperature distribution at the outlet of flow field is most uniform. The tool used for numerical analysis is CFDS-FLOW3D.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2023년도 봄 학술논문 발표대회
• /
• pp.45-46
• /
• 2023

CLC is used as a filling material for many buildings, and according to energy saving design standards, CLC also requires insulation performance. However, it shows lower insulation performance compared to organic insulation, so additional research is needed. Therefore, in this study, the insulation properties of CLC were analyzed by incorporating EPS beads with high insulation performance into CLC. In this experiment, EPS beads and blast furnace slag were replaced, and W/B was fixed at 33%. The EPS Bead mixing ratio was divided into 5 levels: 0, 0.5, 1.0, 1.5, 2.0 (%), and the experimental items were measured for apparent density and thermal conductivity. As a result of the experiment, the apparent density and thermal conductivity tended to decrease as the mixing ratio of EPS beads increased. It is judged that the density decreased due to the low density and the micropores inside, and the thermal conductivity also decreased.

• 한국진공학회지
• /
• 제3권3호
• /
• pp.316-321
• /
• 1994

Rate of mixing of Cu particles to polyimide substrate at interfaces under different thermal treatments was analyzed by Rutherford Backscattering spectroscopy using 2.0 MeV He+ ions. T he mixing rate was a function of annealing temperature and time and was constant at afioxed temperature. The amount of mixing increased linearly with time and the mixing rate increased with temperature. The activation energy for interface mixing between Cu and polyimide was 2.6 kcal/mol. The X-ray studies showed the Cu(111) plane peak changed with annealing time at fixed temperature. The mixing of Cu to polyimide was explained with segmental motion of PI chain and with interaction between functional group of the chain and metal electron donor. The comparisons were made bewteen the mixing induced by ion irradiation and by thermal treatment. The various factors affecting the interface mixing are discussed.

• 한국전산유체공학회지
• /
• 제11권2호
• /
• pp.8-18
• /
• 2006

A CFD benchmark calculation for a steam blowdown test was performed for 30 seconds to develop the methodology of numerical analysis for the thermal mixing between steam and subcooled water. In the CFD analysis, the grid model simulating the sparger and the IRWST pool were developed by the axisymmetric condition and then the steam condensation phenomena by a direct contact was modelled by the so-called condensation region model. Thermal mixing phenomenon in the subcooled water tank was treated as an incompressible flow, a free surface flow between the air and the water, a turbulent flow, and a buoyancy flow. The comparison of the CFD results with the test data showed a good agreement as a whole, but a small temperature difference was locally found at some locations. The commercial CFD code of CFX4.4 together with the condensation region model can simulate the thermal mixing behavior reasonably well when a sufficient number of mesh distribution and a proper numerical method are adopted.

• 한국안전학회지
• /
• 제20권2호
• /
• pp.98-104
• /
• 2005

Saw dust concrete f3r finding out insulation characteristic was tested using test plate $30cm{\times}30cm{\times}5cm$. basically, molds f3r the test of compressive, tensile, normal without sawdust, $0.05\%,\;0.1\%,\;0.2\%,\; 0.4\%,\;0.6\%,\;0.8\%,\;1.0\%,\;1.2\%,\;1.4\%,\;1.6\%,\;1.5\%,\;2.0\%$, mixing proportion. heat conductivity of the saw dust concrete mixed with the above proportion was taken in this study. Thermal conduction of normal concrete depends on mixing proportion strength aggregate character, water content. all these items are specified here in fables. $1.8\%\~2.0\%$ saw-dust mising concrete shows as the faction as normal insulation material has its function. and the higher saw-dust mixing rate becomes, the thermal conduction becomes the less Then, the conclusions are that saw-dust using concrete has better insulation function than normal concrete.

• 한국유체기계학회 논문집
• /
• 제10권5호
• /
• pp.9-19
• /
• 2007

Fluid temperature fluctuations in a mixing tee pipe were numerically analyzed by LES model in order to clarify internal turbulent flows and to develope an evaluation method for high-cycle thermal fatigue. Hot and cold water with an temperature difference $40^{\circ}C$ were supplied to the mixing tee. Fluid temperature fluctuations in a mixing tee pipe is analysed by using the computational fluid dynamics code, FLUENT, Temperature fluctuations of the fluid and pipe wall measured as the velocity ratio of the flow in the branch pipe to that in the main pipe was varied from 0.05 to 5.0. The power spectrum method was used to evaluate the heat transfer coefficient. The fluid temperature characteristics were dependent on the velocity ratio, rather than the absolute value of the flow velocity. Large fluid temperature fluctuations were occurred near the mixing tee, and the fluctuation temperature frequency was random. The ratios of the measured heat transfer coefficient to that evaluated by Dittus-Boelter's empirical equation were independent of the velocity ratio, The multiplier ratios were about from 4 to 6.