• Proceedings of the KWS Conference
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• v.43
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• pp.67-69
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• 2004

The fuel assemblies as the nuclear fuel for the pressurized water reactor(PWR) are loaded in the reactor core throughout the residence time of three to five years. The spacer grid assembly, which is an interconnected array of slotted grid straps and is welded at the intersections to form an egg crate structure, is one of the main structural components of the fuel assembly. The spacer grid assembly is structurally required to have enough buckling strength under various kinds of lateral load acting on the fuel assembly so as to keep the fuel assembly straight. To meet the requirement, integrity on the spacer grid welding parts should be carefully checked. In this study, welding quality of the spacer grid assembly welded by several welding companies are examined and compared.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.11
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• pp.1519-1524
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• 2015

It is well known that prepartum sows have an innate motivation to build a nest before parturition. Under commercial conditions, however, the farrowing crate, which is widely used in modern pig husbandry, inhibits this innate behaviour through the lack of space, materials, or both. Thus, restriction of nest-building behaviour could generate increased stress, resulting in a decrease in maternal endogenous hormones. Hence, it could lead to detrimental effects on farrowing and lactating performance. Here we review interactions between prepartum nest-building behaviour, stress and maternal endogenous hormone levels, and discuss their effects on parturition, lactation, and welfare of sows and offspring.

• Proceedings of the KWS Conference
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• 2006.10a
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• pp.125-127
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• 2006

A spacer grid assembly, which is an interconnected array of slotted grid straps and is welded at the intersections to form an egg crate structure, is one of the main structural components of the nuclear fuel assembly for pressurized water reactors(PWRs). The spacer grid assembly is structurally required to have enough buckling strength under various kinds of lateral loads acting on the nuclear fuel assembly so as to keep the nuclear fuel assembly straight. To meet this requirement, it is necessary to weld the welding parts carefully and precisely. In this study, weld qualities such as, weld bead size, penetration, spatter, etc. manufactured by various welders were compared and analyzed. Comparison results show that the weld qualities could be improved by selecting the optimal welding condition and also improving the welding technique.

• Proceedings of the KWS Conference
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• 2006.05a
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• pp.42-44
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• 2006

A spacer grid assembly, which is an interconnected array of slotted grid straps and is welded at the intersections to form an egg crate structure, is one of the main structural components of the nuclear fuel assembly for pressurized water reactors(PWRs). The spacer grid assembly is structurally required to have enough buckling strength under various kinds of lateral loads acting on the nuclear fuel assembly so as to keep the nuclear fuel assembly straight. To meet this requirement, it is necessary to weld the welding parts carefully and precisely. In this study, a series of welding tests were carried out to find an optimum welding condition. After examining and analyzing the specimens welded from the welding conditions, a recommendable laser welding condition was selected for the KAERI designed Zircaloy spacer grid assembly.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.1
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• pp.68-74
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• 2005

In this work, polymerization conditions of the gel polymer electrolyte (GPE) were studied to obtain better electrochemical performances in a lithium-ion polymer battery. When the polymerization temperature and time of the GPE were 70$^{\circ}C$ and 70 min, respectively, the lithium polymer battery showed excellent a rate capability and cycleability. The TMPETA (trimethylolpropane ethoxylate triacrylate)/TEGDMA (triethylene glycol dimethacrylate)-based cells prepared under optimized polymerization conditions showed excellent rate capability and low-temperature performances: The discharge capacity of cells at 2 Crate showed 92.1 % against 0.2C rate. The cell at -20 $^{\circ}C$ also delivered 82.4 % of the discharge capacity at room temperature.

• Proceedings of the KWS Conference
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• 2005.06a
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• pp.109-111
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• 2005

Nuclear fuel assemblies for pressurized water reactors(PWR) are loaded in the reactor core throughout the residence time of three to five years. A spacer grid assembly, which is an interconnected array of slotted grid straps and is welded at the intersections to form an egg crate structure, is one of the main structural components of the nuclear fuel assembly. The spacer grid assembly is structurally required to have enough buckling strength under various kinds of lateral loads acting on the nuclear fuel assembly so as to keep the nuclear fuel assembly straight. To meet this requirement, it is necessary to weld the welding parts carefully and precisely. In this study, laser welding qualities of the spacer grid assembly welded by several welding companies, such as weld strength, weld penetration depth, and weld bead size, are examined and compared.

• Journal of Animal Environmental Science
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• v.18 no.3
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• pp.157-164
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• 2012

This study was conducted to investigate the effect of different farrowing space, narrow and wide, on the sow performances and piglet growth performances. The $1.5m^2$ of narrow farrowing space was determined as the size of farrowing crate. The $3.0m^2$ of wide space for farrowing sow was the same of farrowing pen to allow the behavior freedom of sow. Baby piglets in the wide farrowing space was protected from crushing of sow by installation of safety bar. The pregnant sows used in this study were stall-housed during gestation and moved to each farrowing spaces on 8 d before parturition. Feed intake, backfat thickness and body condition score of sow were not affected by both farrowing spaces. However, the changes in backfat thickness and body condition score between farrowing and weaning in wide farrowing space were lower (p<0.05) than in narrow farrowing space. The return to estrus of sow was remarkably decreased in wide farrowing space compared to sows in narrow farrowing space. The lower number of stillbirth and higher mortality of piglets were observed in wide farrowing space. From the results, although wide farrowing space could be practically acceptable in terms of sow performances, possible cause of mortality of piglets should be scrutinized through observation of piglet and sow behaviors.

• Nuclear Engineering and Technology
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• v.45 no.4
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• pp.513-522
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• 2013

The ODSCC detected in the TSP position of Ulchin 3&4 SGs are typical ODSCC of Alloy 600MA tubes. The causative chemical environment is formed by concentration of impurities inside the occluded region formed by the tube surface, egg crate strips, and sludge deposit there. Most cracks are detected at or near the line contacts between the tube surface and the egg crate strips. The region of dense crack population, as defined as between $4^{th}$ and $9^{th}$ TSPs, and near the center of hot leg hemisphere plane, coincided well with the region of preferential sludge deposition as defined by thermal hydraulics calculation using SGAP computer code. The cracks developed homogeneously in a wide range of SGs, so that the number of cracks detected each outage increased very rapidly since the first detection in the $8^{th}$ refueling outage. The root cause assessment focused on investigation of the difference in microstructure and manufacturing residual stress in order to reveal the cause of different susceptibilities to ODSCC among identical six units. The manufacturing residual stress as measured by XRD on OD surface and by split tube method indicated that the high residual stress of Alloy 600MA tube played a critical role in developing ODSCC. The level of residual stress showed substantial variations among the six units depending on details of straightening and OD grinding processes. Youngwang 3&4 tubes are less susceptible to ODSCC than U3 and U4 tubes because semi-continuous coarse chromium carbides are formed along the grain boundary of Y3&4 tubes, while there are finer less continuous chromium carbides in U3 and U4. The different carbide morphology is caused by the difference in cooling rate after mill anneal. There is a possibility that high chromium content in the Y3&4 tubes, still within the allowable range of Alloy 600, has made some contribution to the improved resistance to ODSCC. It is anticipated that ODSCC in Y5&6 SGs will be retarded more considerably than U3 SGs since the manufacturing residual stress in Y5&6 tubes is substantially lower than in U3 tubes, while the microstructure is similar with each other.

• Journal of Welding and Joining
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• v.24 no.5
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• pp.22-28
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• 2006

A spacer grid assembly, which is an interconnected array of slotted grid straps and is welded at the intersections to form an egg crate structure, is one of the main structural components of the nuclear fuel assembly for Pressurized Water Reactors (PWRs). The weld quality of spacer grids in PWRs fuel is extremely important for the fuel assembly performance in the nuclear renter. The spacer grid welds are currently evaluated mainly by the metallographic examination although it reveals only cross-points which are welded by the laser beam. This experiment is also to compare the weldability of Zircaloy-4 spacer grids using by the GTA and LB. The effect of node geometries of spacer grids for the GTAW and LBW has been studied and optimum conditions of spacer grid welding have been found. Microstructures and micro-hardness of the GTA and LB welded zones have been also compared.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.10a
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• pp.426-432
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• 2000

This paper presents methods to design an integrated system for supporting both multimedia contents creations and its presentation in a windows system. Especially, it describes methods for designing an integrated editor that can be used to crate and edit various media data including continuous media such as audio and video. And it also proposes a system model for systematically integrating multimedia creating tool with multimedia presentation system where the heeling and scenario-based presentation methods are included in the propose system for supporting effective multimedia presentation through a network Finally, we describe a threads processing technique based on event monitoring to satisfy effectively needs for presentation control, synchronization control, and user's input control during a multimedia presentation.