• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.817-820
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• 2004

Our country was much developments in change of construction environment along with fast economy development. But, various problems that must think in problem of safety and quality were appeared. Constructions which build through rapid economy development are getting many social criticisms to problem of crack and water leakage at use process. Is situation that huge repair expense to cure this is engaged. Safety problem of construction is indicated socially through various media mediums again.

• Korean Journal of Animal Reproduction
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• v.19 no.1
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• pp.43-48
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• 1995

The purpose of this study was to examine the suvival rates of cryopreserved porcine embryos collected on Day 6 (Day 0=onset of estrus) with various cryprotectants. Eighty two embryos at different stages, ranged from expanded blastocyst to hatched blastocyst, were allocated to 6 experimental groups in different combinations of cryoprotectants glycerol, egg yolk and/or trehalose. Porcine embryos were cryopreserved using conventinal slow freezing precedures. The embryos were equilibrated with one of the freezing solutions, cooled from 25 to -7$^{\circ}C$ at 1$^{\circ}C$/min, seeded at -7$^{\circ}C$ frozen to -36$^{\circ}C$ at 0.5$^{\circ}C$/min, and then plunged into liquid nitrogen. The frozen embryos were thawed by immersion in 37$^{\circ}C$ water and the cryoprotectants were removed by dilution with 0.5M sucrose solution. Embryonic survival was estimated from the normal development of embryos for 12, 24 and 48hrs culture. Then the embryos were stained and their cell nuclei was counted. The survival rates of morphological embryos were significantly higher in group I (10% glycerol) or group IV (10% glycerol＋10% egg yolk＋0.5M trehalose) than those in other groups, although the nuclei number was quite higher in embryos treated with 10% glycerol and 0.25M trehalose at expended blastocyst. However, hatched blastocysts showed higher viability and nuclei number treated with either egg york or trehalose, but the survival rates after 48hrs of culture were quite low. These results indicate that egg yolk and trehalos as a supplement to freezing solutions can be useful to the cryopreservation ofn porcine embryos.

• Journal of Convergence for Information Technology
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• v.11 no.1
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• pp.128-135
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• 2021

The possibility and effectiveness of cryopreservation was determined to assess survival rates and improve stock management of thawed embryos of Manila clam, Ruditapes philippinarum. The ideal freezing rates were designed and tested to allow cryoprotectants to equilibrate across the membrane during freezing. Survival rates ranging from 0 to 64.3% were obtained using a stepwise freezing protocol compared with 82.3% control rates. Embryos of Ruditapes philippinarum were equilibrated in 2 CPAs plus sea water for 10 min at 25℃ and then cooled at -1℃/min from 20℃ to -12℃. Straws containing more than 100 embryos were held at 12℃ for 5 min allowing equilibration after seeding and slowly cooled at 2℃/min. to -35℃ for 30 min for equilibration before quenching in liquid nitrogen. Dimethyl sulfoxide (DMSO) is the best cryoprotectant indicated for embryos of R. philippinarum with a survival rate of 64.3±3.28% in the presence of 2.0 M DMSO.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.6
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• pp.580-586
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• 2008

Icing cloud generation system was developed to perform the in-flight icing simulation test for T-50 Supersonic Jet Trainer on the ground. The developed system successfully generated the almost natural icing cloud in the super-cooled state (liquid state) below freezing point and with the required LWC (Liquid Water Content). For full-scale aircraft icing test, an icing scaling method was adopted due to the limitation of wind generation speed with open-circuit type blower and its applicability was experimentally verified. Under the required in-flight icing condition based on the icing scaling method, T-50 aircraft subsystems were successfully operated and functionally checked.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.1195-1203
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• 2006

Water that is treated by passing through a magnetic field of certain strength is called Magnetic Field Treated Water(MFTW). Previous research indicate that use of MFTW can save 5% of cement dosage, decrease bleeding of concrete, and improve resistance to freezing. The reason why MFTW can improve characteristics of concrete can be explained by the molecular structure of water. Magnetic force can break apart water clusters into single molecules or smaller ones, therefore, the activity of water is improved. While hydration of cement particles is in progress, the MFTW can penetrate the core region of cement particles more easily. Hence, hydration takes place more efficiently which in turn improves concrete compressive strength. Test results demonstrate that the compressive strength of the sodium silicate cement grout homogel increases by approximately 20 - 50% by using the MFTW.

• Current Research on Agriculture and Life Sciences
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• v.5
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• pp.75-80
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• 1987

We investigated physico-chemical properties of hard wheat flours for frozen yeast-raised breadmaking and freezing stability of frozen dough prepared by the straight no-time method. The general Composition of wheat flours were : moisture ; 14.0%, ash ; 0.48%. protein ; 13.15%, and dry gluten ; 13.43%. In farinograph data, development time and water absorption were 5.5 mimutes and 62 %, respectively. Amylograph maximum viscosity was 500 BU. Resistance to extention increased with the time and their extensibility decreased in the extensigraph data. From these results obtained from these physico-chemical properties, it was confirmed that the used wheat flours were most suitable for bread-baking. Considering effect of gassing power on cold storage period and fermentation time, it was effective that dough temperature should be adjusted to $20^{\circ}C$ in order to decrease freezing injury and maintain freezing stability.

• Applied Chemistry for Engineering
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• v.4 no.1
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• pp.125-131
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• 1993

The state of water in various modified cellulose membranes such as [carboxymethyl cellulose(CMC)-gelatin] polyelectrolyte complex, methylcellulose(MC) grafted with acrylic acid(AA), [(MC-g-AA)-gelatin] polyelectrolyte complex, were determined by differential scanning calorimetric technique. The amounts of freezing(free) and nonfreezing(bound) water were estimated to determine the permeability coefficient of solutes through membranes. The state of water in membranes were influenced by the states of the composition, morphology, and their water content. The difference in diffusive permeability through the water-swollen membranes can be explained by the difference in the free and bound water content.

• Proceedings of the SAREK Conference
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• 2005.06a
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• pp.23-23
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• 2005

• Journal of Applied Biological Chemistry
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• v.43 no.4
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• pp.211-217
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• 2000

Oxidative stress is implicated in a number of diseases, in ageing of organisms, and in damage to plants that have been exposed to freezing and thawing or water stress. From the perspective of yeast as a model eukaryotic system, this article reviews the systems that are involved in the cellular responses to exposure to reactive oxygen species (ROS) generated during aerobic growth of the organism. The discussion includes the defense systems involved, the ability of cells to adapt to ROS treatment, cell-division cycle delay and the systems regulating gene expression that are activated by oxidative stress.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.47-50
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• 2008

The sub-zero cold is a major environmental consideration for the operational readiness of FCEVs because fuel cells produce water and utilize wet air with varying water content to generate electricity. Typical fuel cells thus have a fatal flaw in freezing conditions at startup. This drawback becomes more serious with the outsourced fuel cell that is entirely water-based for its internal humidification. In this background, the HMC's self-designed fuel cell was developed as an alternative and was employed in the Tucson-based FCEV in 2006 demonstrating its good cold-startup characteristics. The cold-startup capacity of the vehicle was validated through tests in the cold chamber and on the road, resulting in 50% stack power achieved in 250 seconds at $-15^{\circ}C$.