• Transactions of the Korean hydrogen and new energy society
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• v.27 no.2
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• pp.163-168
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• 2016

Korea has been developing nuclear fusion fuel storage and delivery system (SDS) technologies including a basic scientific study on hydrogen storage. To develop nuclear fusion technology, it is necessary to store and supply hydrogen isotopes needed for Tokamak operation. SDS is used for storing hydrogen isotopes as a metal hydride form. The rapid hydriding of tritium is very important not only for safety reasons but also for the economic design and operation of the SDS. In this study, we designed and fabricated a medium-scale getter bed of depleted uranium (DU). The hydriding of DU has been measured by varying the initial temperature ($100-300^{\circ}C$) of the DU getter bed to investigate the influence of the cooling temperature. Furthermore, we analyzed the effect of a helium blanket on the hydriding performance with 0 - 12% helium content in hydrogen.

• Nuclear Engineering and Technology
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• v.8 no.1
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• pp.9-17
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• 1976

Dosimetrical properties of polycarbonate film for high-level dosimetry of electrons have been examined. Polycartonate film of 0.1mm in thickness was chosen for this purpose. It can cover the dose range of 1.0-130 Mrad and the measurable range can be extended up to 200 Mrad by using calibration curve. The measurement error was within 3.5%. The radiation induced optical density at 330nm shows rapid initial fading of 7-l3n for one day after irradiation at room temperature and subsequent fading rate is very small, about 0.6% per day. The fading depends on the absorbed dose, storage temperature, and wavelengths. The effects of storage time and temperature during and after irradiation of this film are presented. For practical dosimetry, it is necessary to stabilize the induced optical density by storing the irradiated film for a day or by heat treatment at 10$0^{\circ}C$ for an hour.

• Progress in Superconductivity and Cryogenics
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• v.23 no.3
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• pp.55-59
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• 2021

A thermoelectric cooler (TEC) is promising as an alternative refrigeration technology for the sake of its inherent advantages; no-moving parts and refrigerant-free in its operation. Due to the compactness, reliability and excellence in temperature stability, TECs have been widely used for small cooling devices. In recent years, thermoelectric devices have been attractive technologies that not only serve the needs of cooling and heating applications but also meet the demand for energy by recycling waste heat. In this research paper, multistage TEC is proposed as a concept of demonstrating the idea of transient cooling technology. The key idea of transient cooling is to harnesses the thermal mass installed at the interfacial level of the stages. By storing heat temporally at the thermal mass, the multistage TEC can readily reach lower temperatures than that by a steady-state operation. The multistage TEC consists of four different sizes of thermoelectric modules and they are operated with an optimized current. Once the cold-part of the uppermost stage is reached at the no-load temperature, the current is successively supplied to the lower stages with a certain time interval; 25, 50 and 75 seconds. The results show the temperatures that can be ultimately reached at the cold-side of the lowermost stage are 197, 182 and 237 K, respectively. It can be concluded that the timing or total amount of the current fed to each thermoelectric module is the key parameter to determine the no-load temperature.

• Nuclear Engineering and Technology
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• v.43 no.4
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• pp.391-398
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• 2011

The U metal chips generated in developing nuclear fuel and a gamma radioisotope shield have been stored under immersion of water in KAERI. When the water of the storing vessels vaporizes or drains due to unexpected leaking, the U metal chips are able to open to air. A new oxidation treatment process was raised for a long time safe storage with concepts of drying under vacuum, evaporating the containing water and organic material with elevating temperature, and oxidizing the uranium metal chips at an appropriate high temperature under conditions of controlling the feeding rate of oxygen gas. In order to optimize the oxidation process the uranium metal chips were completely dried at higher temperature than $300^{\circ}C$ and tested for oxidation at various temperatures, which are $300^{\circ}C$, $400^{\circ}C$, and $500^{\circ}C$. When the oxidation temperature was $400^{\circ}C$, the oxidized sample for 7 hours showed a temperature rise of $60^{\circ}C$ in the self-ignition test. But the oxidized sample for 14 hours revealed a slight temperature rise of $7^{\circ}C$ representing a stable behavior in the self-ignition test. When the temperature was $500^{\circ}C$, the shorter oxidation for 7 hours appeared to be enough because the self-ignition test represented no temperature rise. By using several chemical analyses such as carbon content determination, X-ray deflection (XRD), Infrared spectra (IR) and Thermal gravimetric analysis (TGA) on the oxidation treated samples, the results of self-ignition test of new oxidation treatment process for U metal chip were interpreted and supported.

• The Korean Journal of Pesticide Science
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• v.15 no.1
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• pp.55-60
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• 2011

To work out quality control methods of environmental-friendly organic materials (EFOMs), the reason and basis for EFOM-selection and farmer's favorite formulation type of EFOMs, etc were investigated on farmers who had been practicing environmental-friendly agriculture. EFOMs used were soil amendments, control agents of plant diseases and insect pests, plant growth promotion formulations, in turns. In EFOMs application time, 22.7% of farmers sprayed EFOMs without delay after they were bought, in other hand, 77.3% of farmers used EFOMs which had been bought and stored for some period. Microbial density on seventeen environmental-friendly microbial formulates (EFMFs) including microbial pesticides, a microbial fertilizer, and environmental-friendly organic materials was investigated at different storing temperature and shelf life. When the microbial density of EFMFs was investigated without delay after they were bought, all used microbial pesticides and a microbial fertilizer was confirmed to be optimal for the certified density but two of environmental-friendly organic materials was confirmed not to be optimal. When microbial density of 17 EFMFs were investigated after storing them for six months at $4^{\circ}C$, only one of 9 microbial pesticides was confirmed not to be optimal, the other hand four of seven environmental-friendly organic materials not to be optimal, which each of their microbial density was less than the certified density. Population dynamics of microbial agents was much more influenced in fluctuated temperature (room temperature) than in static temperature condition ($5^{\circ}C$ and $25^{\circ}C$). Shelf life of microbial agents according to microbial formulation type were high in granule type, liquid wettable type and liquid type in turns.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.12
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• pp.1703-1708
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• 2009

Deproteinization has been recognized as a prerequisite for amino acid analysis of plasma samples. For plasma stored at room temperature, delaying deproteinization for 30, 60 or 120 minutes did not result in significant changes in the mean CV (coefficient of variation), which ranged from 4.4 to 5.6%. However the mean CV of aspartic acid, ${\alpha}$-aminoadipic acid, alanine and lysine was about 10%. When the plasma was stored frozen at -20${^{\circ}C}$, the CV was increased at 0 and 120 minutes after thawing, to 12.4% (range, 4.1 to 35.3%) and 8.0% (2.5 to 30.7%), respectively. The concentrations in plasma during storage at room temperature of all the amino acids analyzed showed significant changes. In plasma stored for 30 minutes at room temperature, 17 amino acids increased in concentrations and two decreased. Extending this period to 60 or 120 minutes increased the instability as compare to the reference group. Storing plasma at -20${^{\circ}C}$ for 2 weeks resulted in significantly greater changes in the amino acid concentrations than at room temperature. On extending the storage time at room temperature, after thawing, to 30, 60, and 120 minutes, 21, 20, and all 22 amino acids respectively changed significantly (p<0.01). The present study indicates that methodological errors occur in the concentrations determined for all amino acids when plasma is left at room temperature. The storage of frozen non-deproteinized plasma accompanied more significant changes in most amino acid concentrations and thus should be avoided. Deproteinization should be performed as soon as possible after plasma collection.

• KIEAE Journal
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• v.16 no.3
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• pp.89-94
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• 2016

Purpose: This study aimed at developing an artificial neural network (ANN) model to predict the optimal start moment of the setback temperature during the normal occupied period of a building. Method: For achieving this objective, three major steps were conducted: the development of an initial ANN model, optimization of the initial model, and performance tests of the optimized model. The development and performance testing of the ANN model were conducted through numerical simulation methods using transient systems simulation (TRNSYS) and matrix laboratory (MATLAB) software. Result: The results analysis in the development and test processes revealed that the indoor temperature, outdoor temperature, and temperature difference from the setback temperature presented strong relationship with the optimal start moment of the setback temperature; thus, these variables were used as input neurons in the ANN model. The optimal values for the number of hidden layers, number of hidden neurons, learning rate, and moment were found to be 4, 9, 0.6, and 0.9, respectively, and these values were applied to the optimized ANN model. The optimized model proved its prediction accuracy with the very storing statistical correlation between the predicted values from the ANN model and the simulated values in the TRNSYS model. Thus, the optimized model showed its potential to be applied in the control algorithm.

• Journal of the Korea Concrete Institute
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• v.19 no.5
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• pp.647-653
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• 2007

In ready mixed concrete factory, in case of using the high molecular additive in winter especially the liquid additive for the early strength, it is required to check the stability. In this research, the freezing and gelling characteristics of the liquid additive for the early strength is reviewed, the material and mechanical solution are proposed to that the practical quality control method will be suggested. As the result, the Freezing temperature of the liquid additive for the early strength is $-11.8^{\circ}C$, and it is the lower than the temperature at which the strength is shown. By making with sodium silicate of $37{\pm}0.5%$ designed by $SiO_2\;and\;Na_2O$ in 0.31 of mol ratio, it minimizes the gelling at the lower temperature. On the other hand, facilities for storing and supplying the material should be set at $40^{\circ}C$ so the temperature distribution is well spreaded for practical operation.

• Journal of Digital Convergence
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• v.14 no.4
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• pp.259-265
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• 2016

In this paper, a remote control system capable of monitoring and controlling the temperature of a refrigerator in real time using the ZigBee communication technology is developed. The developed system provides 24-hour surveillance function including temperature maintenance and it is able to determine monitored data from a remote location and to change the setting of the temperature value. In case the value is out of the setting, it is designed for administrators to verify the problem and take action, sending alarms to management server and the emergency to a preset administrator via SMS. Applying this system to refrigerators storing commercial, medical, and experimental material, the real time status such as temperature and malfunction of refrigerator can be managed up to 16 SZM(Slave Zigbee Module) by only one MZM(Master Zigbee Module).

• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.162-167
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• 2011

Thermal storage plays an important role in building energy saving, which is greatly assisted by the incorporation of latent heat storage in building materials. A phase change material is a substance with a high heat of fusion which, melting and solidifying at a certain temperature, can be storing and releasing large amount of energy. Heat is stored or released when the material changes from solid to liquid. Integration of building materials incorporating PCMs into the building envelope can result in increased efficiency of the built environment. The aim of this research is to identify thermal performance of PCMs impregnated building materials which is applied to interior of building such as gypsum and red clay. In order to analyze thermal performance of phase change materials, test-cell experiments and simulation analysis were carried out. The results show that micro-encapsulated PCM has an effect to maintain a constant indoor temperature using latent heat through the test-cell experiments. PCM wallboard makes it possible to reduce the fluctuation of room temperature and heating and cooling load by using EnergyPlus simulation program. Phase change material can store solar energy directly in buildings. Increasing the heat capacity of a building is capable of improving human comfort by decreasing the frequency of indoor air temperature swings so that the interior air temperature is closer to the desired temperature for a long period of time.