• Korean Journal of Animal Reproduction
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• v.8 no.2
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• pp.116-121
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• 1984

These experiments were carried out to examine the effect of rapid thawing (500$^{\circ}C$/min) on the survival of 8-cell mouse embryos cooled slowly (0.5-1$^{\circ}C$/min) to precooling temperatures between -10 and 070$^{\circ}C$ before direct transfer ofembryos to -196$^{\circ}C$, and to compare the survival of embroys thawed slowly (20$^{\circ}C$/min) and rapidly (500$^{\circ}C$/min) after in vitro culture. In addition, the sensitivity of 8-cell mouse embroys to the rate of addition and removal of cryoprotectant at room temperauture, and the effect of developing stages on the survival of embryos frozen-thawed slowly were investigated. The results obtained were summarized as follows: 1. Embryos were survived in rapid thawing (500$^{\circ}C$/min) only when slow cooling was terminated at relatively high subzero teperaure (-20 to -60$^{\circ}C$). The highest survival rate(77.0%) in in vitro culture of embryos thawed rapidly was obtaeined after transfer to -196$^{\circ}C$ from -40$^{\circ}C$. 2. For the survival of embryos in slow thawing (20$^{\circ}C$/min.), slow cooling to lower subzero temperature (-50$^{\circ}C$ and below) was required before transfer of embryos to -196$^{\circ}C$. These results indicate that embryos transferred to -196$^{\circ}C$ from high subzero temprature contain much interacellular ice to damage them during slow warming but to permit survival of embryos after rapid warming. 3. The Survival rate (72.7%) of 8-cell mouse embryos after rapid addition and removal of cryoprotectant, DMSO at room temperature was similar to that (83.9%) after slow addition and removal of cryoprotectant at same temperature. 4. The survival rates of 1-, 2-, 4- and 8-cell embryos frozen-thawed slowly were 26.7, 76.4, 70.0 and 83.9%, respectively.

• Geomechanics and Engineering
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• v.27 no.5
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• pp.433-445
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• 2021

Artificial ground freezing (AGF) is a commonly used geotechnical support technique that can be applied in any soil type and has low environmental impact. Experimental and numerical investigations have been conducted to optimize AGF for application in diverse scenarios. Precise simulation of groundwater flow is crucial to improving the reliability these investigations' results. Previous experimental research has mostly considered horizontal seepage flow, which does not allow accurate calculation of the groundwater flow velocity due to spatial variation of the piezometric head. This study adopted vertical seepage flow-which can maintain a constant cross-sectional area-to eliminate the limitations of using horizontal seepage flow. The closure time is a measure of the time taken for an impermeable layer to begin to form, this being the time for a frozen soil-ice wall to start forming adjacent to the freeze pipes; this is of great importance to applied AGF. This study reports verification of the reliability of our experimental apparatus and measurement system using only water, because temperature data could be measured while freezing was observed visually. Subsequent experimental AFG tests with saturated sandy soil were also performed. From the experimental results, a method of estimating closure time is proposed using the inflection point in the thermal conductivity difference between pore water and pore ice. It is expected that this estimation method will be highly applicable in the field. A further parametric study assessed factors influencing the closure time using a two-dimensional coupled thermo-hydraulic numerical analysis model that can simulate the AGF of saturated sandy soil considering groundwater flow. It shows that the closure time is affected by factors such as hydraulic gradient, unfrozen permeability, particle thermal conductivity, and freezing temperature. Among these factors, changes in the unfrozen permeability and particle thermal conductivity have less effect on the formation of frozen soil-ice walls when the freezing temperature is sufficiently low.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.12
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• pp.1750-1756
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• 2011

This study evaluated the effect of antioxidants treatment; (Vit. C and E) on the physicochemical and sensory properties of Tarakjuk treated with gamma-irradiation under two different temperature conditions, e.g. room and frozen temperatures. In samples of Tarakjuk irradiated at room temperature, Vit. C gradually decreased the pH level as the concentration increased (p<0.05), whereas Vit. E did not. Addition of both Vit. C and E to Tarakjuk decreased TBA (2-thiobarbituric acid) value while also increasing viscosity. However, these antioxidants did not cause any change in Hunter's color values. Sensory properties showed that Vit. C and E significantly improved the overall acceptability of Tarakjuk, and the addition of 0.1% each Vit. C and E was best treatment. In samples of Tarakjuk subjected to combined treatment with antioxidants and irradiation under frozen temperature conditions, Vit. C and E were effective in decreasing TBA value, improving viscosity, and maintaining sensory quality. Especially, co-treatment with 0.1% Vit. C and E augmented the observed effect (p<0.05). Therefore, combined treatment with antioxidants and irradiation under frozen temperature conditions could improve the final sensory quality of gamma-irradiated Tarakjuk.

• Journal of IKEEE
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• v.23 no.1
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• pp.159-163
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• 2019

The food service industry has been grown due to improvement of living standards. In addition, the demand for frozen food delivery is increasing day by day at online/offline and the refrigerated vehicles are used in most of these food distributions. One of the most important factors in a refrigerated car is to measure the temperature accurately. Conventional temperature recording systems are generally connected directly to temperature sensor modules. Since the temperature data are transmitted to the temperature recorder by using the electric wire, there is a disadvantage that the resistance error must be compensated according to the cable length. In this paper, we propose a method to correct errors due to cable resistance using digital processing and CAN (Controller Area Network) communication. We use PT-1000 platinum sensor to increase the accuracy of the temperature measurement.

• Journal of the Korean GEO-environmental Society
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• v.14 no.12
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• pp.23-30
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• 2013

Bearing capacity of pile is governed by only skin friction in frozen ground condition, while it is generally governed both by skin friction and end bearing capacity in typically unfrozen ground condition. Skin friction force, which arises from the interaction between pile and frozen soils, is defined as adfreeze bond strength, and adfreeze bond strength is one of the most important key parameters for design of pile in frozen soils. Many studies have been carried out in order to analyze adfreeze bond strength characteristics over the last fifty years. However, many studies for adfreeze bond strength have been conducted with limited circumstances, since adfreeze bond strength is sensitively affected by various influence factors such as intrinsic material properties, pile surface roughness, and externally imposed testing conditions. In this study, direct shear test is carried out inside of large-scaled freezing chamber in order to analyze the adfreeze bond strength characteristics with varying freezing temperature and normal stress. Also, the relationship between adfreeze bond strength and shear strength of the frozen soil obtained from previous study was analyzed. The coefficient of adfreeze bond strength was evaluated in order to predict adfreeze bond strength based on shear strength, and coefficients suggested from this and previous studies were compared.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.2
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• pp.246-253
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• 2012

In this study, we determined the optimum blanching conditions for pretreatment of Aster scaber prior to freezing to ensure its long, safe preservation as a fine cooking ingredient. Frozen-thawed A. scaber did not significantly differ between blanching groups, but the blanched group showed significantly higher Hunter L, a, and b values than the un-blanched group (p<0.05). Higher temperatures and longer treatment times increased softness; hardness did not significantly differ between the blanched and un-blanched groups of frozen-thawed A. scaber (p<0.05). Total bacterial counts and the presence of coliforms seemed to decline with blanching treatments, but treatment temperature and time did not influence this reduction. Over 95% of peroxidase activity was inactivated by blanching treatment but increased slightly after thawing. The sensory evaluation of the frozen-thawed A. scaber by test group showed the A. scaber blanched at $90^{\circ}C$ for 3 min to be the most highly preferred (p<0.05).

• Journal of Digital Convergence
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• v.18 no.4
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• pp.55-65
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• 2020

The factors for service quality improvement of frozen and refrigerated warehouses are derived and the differences in perception about service quality improvement between shippers and operators of frozen and refrigerated cargos are analyzed. The objective of this study is to propose quality improvement measures for frozen and refrigerated cargo services using the importance-performance analysis (IPA). As a result, 15 analysis factors were derived. It was found through independent sample t-test that there is no difference in perception about quality improvement between shippers and operators. Furthermore, four top priority investment areas were derived from the IPA: maintaining temperature and humidity, securing variable storage space, on-time stocking and releasing, and providing information service. Meanwhile, inventory management service ability, on-time stocking and releasing, and reliable cargo storage ability needed urgent improvement. This study has industrial implications in that it proposes practical improvement measures for service quality improvement.

• Korean Journal of Food Science and Technology
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• v.38 no.1
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• pp.42-46
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• 2006

Rheological properties of the dough added with milk proteins and gums was studied to investigate the possibilities as anti-staling agents. Also, physical properties of the resultant bread baked from the frozen dough after 8 weeks of storage at $-20^{\circ}C$ were examined. The 4 sets of their combinations of milk proteins and gums, $casein-{\kappa}-carrageenan$ (CK), casein-sodium alginate (CA), $whey-{\kappa}-carrageenan$ (WK), and whey-sodium alginate (WA), were added to dough to examine their possible anti-staling effects. Rheological properties of dough were evaluated, and physical properties of resultant bread baked from frozen dough after 8 weeks storage at $-20^{\circ}C$ were examined. Addition of all treatments increased gelatinization temperature and water absorption, and lowered miximum viscosities and extension of doughs, compared to the control. Doughs added with CA and WA showed longer development times than that of the control. Addition of WK and WA resulted in lowest dough extensions. Treated bread showed lower moisture content decrease during storage at $5^{\circ}C$ for 4 days. Breads baked with frozen doughs after 6 weeks storage at $-20^{\circ}C$ showed similar results. Although textural hardness of breads increased with storage at $5^{\circ}C$, CA- and WA-added breads were less affected, showing they effectively retarded staling of breads.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2002.11a
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• pp.78-78
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• 2002

The role of heat shock proteins in shielding organism from environmental stress is illustrated by the large-scale synthesis of these protein by the organism studied to date. However, recent evidence also suggests an important role for heat shock protein in fertilization and early development of mammalian embryos. Effects of elevated in vitro temperature on in vitro produced bovine embryos were analysed in order to determine its impact on the expression of heat shock protein 70 (HSP70) by control and frozen-thawed after in vitro fertilization (IVF) or nuclear transfer (NT). The objective of this study was to assess the developmental potential in vitro produced embryos with using of the various containers and examined expression and localization of heat shock protein 70 after it's frozen -thawed. For the vitrification, in vitro produced embryos at 2 cell, 8 cell and blastocysts stage after IVF and NT were exposed the ethylene glycol 5.5 M freezing solution (EG 5.5) for 30 sec, loaded on each containers such EM grid, straw and cryo-loop and then immediately plunged into liquid nitrogen. Thawed embryos were serially diluted in sucrose solution, each for 1 min, and cultured in CRI-aa medium. Survival rates of the vitrification production were assessed by re-expanded, hatched blastocysts. There were no differences in the survival rates of IVF using EM grid, cryo-loop. However, survival rates by straw were relatively lower than other containers. Only, nuclear transferred embryos survived by using cryo-loop. After IVF or NT, in vitro matured bovine embryos 2 cell, 8 cell and blastocysts subjected to control and thawed conditions were analysed by semiquantitive reverse transcription polymerase chain reaction methods for hsp 70 mRNA expression. Results revealed the expression of hsp 70 mRNA were higher thawed embryos than control embryos. Immunocytochemistry used to localization the hsp70 protein in embryos. Two, 8-cell embryos derived under control condition was evenly distributed in the cytoplasm but appeared as aggregates in some embryos exposed frozen-thawed. However, under control condition, blastocysts displayed aggregate signal while Hsp70 in frozen-thawed blastocysts appeared to be more uniform in distribution.

• Transactions of Materials Processing
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• v.15 no.1 s.82
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• pp.15-20
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• 2006

The rapid thermal response (RTR) molding is a novel process developed to raise the temperature of mold surface rapidly to the polymer melt temperature prior to the injection stage and then cool rapidly to the ejection temperature. The resulting filling process is achieved inside a hot mold cavity by prohibiting formation of frozen layer so as to enable thin wall injection molding without filling difficulty. The present work covers flow simulation of thin wall injection molding using the RTR molding process. In order to take into account the effects of thermal boundary conditions of the RTR mold, coupled analysis with transient heat transfer simulation is suggested and compared with conventional isothermal analysis. The proposed coupled simulation approach based on solid elements provides reliable thin wall flow estimation for both the conventional molding and the RTR molding processes.