• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• 제3권3호
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• pp.197-205
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• 1991

A numerical study has been performed to investigate two dimensional natural convection heat transfer in a rectangular enclosure with heat sources of constant temperature at the bottom. Calculations were made for various dimensionless heat source lengths, W/L=0.1-0.5, and positions of heat sources at $Gr=2.57{\times}10^6$, Pr=0.71 and Ks/Kf=28.98. For various positions of heat sources, the maximum local Nusselt numbers generally show X=0.81-0.85 at the bottom and X=0.23 at the top. For various dimensionless heat source lengths, the maximum local Nusselt numbers at the bottom show W/L=0.4 for one heat source, W/L=0.2 for two heat sources with fixed centers, W/L=0.5 for two heat sources with moved centers. Finally the maximum heat transfer at the bottom exhibits in condition of W/L=0.4 for two heat sources with moved centers.

• Proceedings of the SAREK Conference
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.1285-1290
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• 2008

The interest in use of new field of energy and unused existing potential energy has been raised in number of advanced countries including South Korea. As a respond of the interest and the following reactions, a new technology which helps to reduce bad environmental factors and decrease national energy consumption rate in the way of extract cold-heat energy in dam water. This research focuses on a method that enables taking the water flows in desirable temperature range whilst keeping water temperature boundaries of bottom level water. The analysis was made in simulating on CFD. In order to keep the temperature boundary level, a deep well pump was set in piping in the simulation. As the significant result, the most alteration in temperature was found when the smallest size of pipe was plumbed. However, when the flow has small value of velocity, no matter how big the piping size was, the temperature variation was negligible. Therefore, possible hypothesis was made as bigger piping as fast flow will have better function in the way to keep the temperature boundary level.

• Journal of Korean Society for Atmospheric Environment
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• 제23권E2호
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• pp.74-81
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• 2007

Feasibility test for a biofilter was performed to treat VOCs. The applied loading rate to the biofilter was calculated between 60 to $3,700\;kg\;COD/m^3$. Trimethyl-pentene and trimethyl-hexene were the two most dominant compounds and they occupy about 85 percent. During the acclimation period, it is desirable for a biofilter to receive relatively lower VOCs concentration and flow rate, until it can adjust to new substrate and operational environment. Temperature at various points inside the biofilter reactor was observed with more than 23 temperature sensors. With steam heating, temperatures of the top sections of the media were greater than those of bottom sections. Without steam heating, intermediate stages generally had higher temperature measurement than those of bottom and top stages. Because the pH values for different biofilter materials vary significantly, measurement of the pH for the mixture of different combinations of biofilter materials is necessary. Based on the types and brands of media, the measured pH ranged from 5.38 to 9.10. The range of measured pH of different mixtures with perlite, compost, saw dust, peat moss, limestone, vermiculite was 7.05 to 8.62.

• Proceedings of the KSME Conference
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.497-502
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• 2001

Three-dimensional natural convection from a discrete flush-mounted circular heat source on the bottom of a cubic enclosure was studied by using a holographic interferometric tomography. The heat source was located at the off-center of the bottom plate so that three-dimensional temperature field can be achieved. A set of multidirectional holographic interferogram was recorded by employing a double-reference beam, double-exposure holographic technique in order to eventually reconstruct the temperature fields. The recorded interferometric data appear good enough to be further processed to extract optical pathlength data from them and finally reconstruct the temperature fields. A complete analysis of the temperature fields including the field reconstructions and comparison with thermocouple measurements is underway and will be reported shortly.

• 한국해양학회지
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• 제22권4호
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• pp.228-235
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• 1987

Based on the hydrographic data for 19 years (1968-1984) at 65 stations in the West Sea of Korea, we investigate the relationships between the sea surface temperature (SST) in winter and the bottom water temperature (BWT) in summer. The spatially-averaged anomalies of BBT are highly correlated with those of SST during the preceding winter. However, due to advection of heat by ocean currents, the spatial pattern of BWT anomaly in summer does not closely resemble that of SST anomaly in the preceding winter.

• 한국해양학회지
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• 제11권2호
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• pp.89-95
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• 1976

Some factors of seawater such as water temperature, salinity, pH, dissolved oxygen and asturation of dissolved oxygen were determined in 5 meters intervals from surface to bottom at 11 stations in Yeongil Bay of Korea during late October 1973. Distribution pattern of water masses in Yeongil Bay during the period seemed to be heterogeneous as dividing into two parts of surface and bottom. Water temperature, pH, dissolved oxygen and saturation of dissolved oxygen of surface water mass showed higher values and salinity of the mass showed lower values than those factors of bottom water mass. Surface water mass might be originated from Tsushima current during summer season and bottom water mass from cold body of East Sea of Korea which seemed to extend to coastal zone during winter season. Land water discharge from Hyeongsan River into the Bay is considered as a minor factor playing slight role in the water mass composition of the area.

• Transactions on Electrical and Electronic Materials
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• 제4권1호
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• pp.15-20
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• 2003

NiCr alloys are prepared onto poly-Si/ $SiO_2$/Si substrates to replace Pt bottom electrode with a new one for integration of high dielectric constant materials. Alloys deposited at Ni and Cr power of 40 and 40 W showed optimum properties in the composition of N $i_{1.6}$C $r_{1.0}$. The grain size of films increases with increasing deposition temperature. The films deposited at 50$0^{\circ}C$ showed a severe agglomeration due to homogeneous nucleation. The NiCr alloys from the rms roughness and resistivity data showed a thermal stability independent of increasing annealing temperature. The 80 nm thick BST films deposited onto N $i_{1.6}$C $r_{1.0}$/poly-Si showed a dielectric constant of 280 and a dissipation factor of about 5 % at 100 kHz. The leakage current density of as-deposited BST films was about 5$\times$10$^{-7}$ A/$\textrm{cm}^2$ at an applied voltage of 1 V. The NiCr alloys are possible to replace Pt bottom electrode with new one to integrate f3r high dielectric constant materials.terials.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제15권12호
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• pp.7350-7356
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• 2014

To study the reasonable design thermal loads, a steel box girder bridge specimen, which has no concrete slab, was manufactured with real size dimensions. The temperature data was obtained at the web and diaphragm using thermo gauges that were attached according to height. In the hottest day, the temperature differences between the top and bottom of the bridge model were calculated. The temperatures in the actual bridge were measured and the temperature of the bridge specimen was compared. The temperature gradient models were proposed in both the web and the diaphragm. The proposed models showed a correlation of approximately 95.8% compared to the Euro code. This study can provide basis data for temperature-load design in the nation.

• Journal of the Korea Organic Resources Recycling Association
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• 제25권4호
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• pp.51-60
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• 2017

Bottom ash(BA) from coal-fired power plants is burnt and remaining ash at high temperature. Since the BA is baked at high temperature, it is considered to be the same function as the elvan. Nowadays, the demand for mortar with far infrared rays, antibacteria, antifungus, deodorization, aridity and humidity function is increasing as the materials such as Hwangtoh(yellow soil) and elvan rather than general mortar. As a result of comparing the functionality of eco-friendly bio BA mortar with that of general mortar, the far infrared ray emissivity is about $0.02{\times}10^2W/m^2$ more and the deodorization function is about 26% or more. Even in the case of humidity control, BA motors showed about 1.8 times higher than general mortar, and more than 10% higher than the "good" standards of moisture absorption and damp proofing construction materials established by the Ministry of Land, Transport and Maritime Affairs.

• Proceedings of the Korea Concrete Institute Conference
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.805-808
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• 2002

This study is designed to reduction of hydration heat of 4 layer division-placed mass concrete considering the difference of setting time of super retarding agent. According to the results, peak temperature of plain concrete by hydration heat show $63^{\circ}C$ around the age of 1 days. Hydration heat is lowest in the bottom layer, and highest in the middle of 3rd layer from the bottom. Hydration heat of mock up structure, which is division-placed at the same interval of 1 and 2 days by setting time difference of super retarding agent, is highest in the bottom layer because after peak temperature of 4th layer, hydration reaction progresses in order of 3rd, 2nd and 1st layer. But in mock up structure which is division-placed at the various interval. peak temperature by hydration heat is reduced by about $13^{\circ}C$, compared with plain concrete because after first peak hydration heat of 4th layer (plain concrete), hydration reaction progresses after the drop of hydration heat in order of 3rd, 2nd and 1st layer.