• Journal of the Korean Geosynthetics Society
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• v.21 no.4
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• pp.31-40
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• 2022

Recently, the Arctic resource development project, where undeveloped energy resources (oil, natural gas, etc.) are deposited, is actively being promoted for the perspective of diversifying the construction market and developing future energy resources. However, the frozen ground always has problems such as sinking and frost-heaving due to extreme weather. Therefore, it is necessary to analyze the thermal characteristics of the frozen soil to secure the stability of the ground structure. In this study, a series of laboratory tests were performed to evaluated the thermal characteristics of frozen soil samples in the oil sand field in Alberta, Canada. In additon, it was compared with the results of domestic(Gangwond-do) sample performed under the same conditions. As a comparison results of the experiments, it was clarified that the different frozen water content and thermal conductivity characteristics by temperature after completion of freezing could affect the frozen soil behavior.

• The Journal of Engineering Geology
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• v.11 no.1
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• pp.13-23
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• 2001

Rock slope near the road or railroad is affected by the outside temperature and iterative freezing-thawing process during winter and early spring. The purpose of this study is to analyze the stability of rock slope which is iniluenced by deterioration due to the freezing-thawing. Method of analysis is homogenization method which find the strength property of discontinuous rock mass and as a strength failure criterion, Drucker-Prager failure criterion is used, The deterioration property of real rock is obtained by a freezing-thawing labordtory test of tuff and this quantitative property is used as a basic data of stability analysis of rock mass. To evaluate the deterioration depth due to the freezing-thawing in the field rock slope, one dimensional heat conductivity equation is used and as a a result we can find the depth of which is affected by a temperature. After determined the freezing-thawing depth of model slope, the pattern of rock mass strength value of model rock slope which excess the limit of self-load is analyzed.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.277-280
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• 2008

Reinforced concrete structures have an excellent durability under a good construction and continuous maintenance. But reinforced concrete construction is influenced by atmospheric phenomena and it is creating a deterioration. One of the deterioration cause on concrete is a freezing and thawing action. Freezing and thawing leads to the reduction in concrete durability by the cracking or surface spalling. If we are carried out freezing and thawing, deterioration of reinforced concrete construction will be reduction. Therefore, this study was performed to investigate the flexural behavior of reinforced concrete beams exposed to freezing and thawing cycles. Thee presence of damage and cycles were considered as variablees in this study.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.6 s.58
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• pp.126-134
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• 2009

Generally, reinforced concrete structures exposed to the outside temperature are affected by freezing and thawing process during winter and early spring. These freeze-thawing process can lead to the reduction in durability of concrete as cracking or surface spalling. This paper is to study the flexural behavior of RC beams exposed to freeze-thawing environments. To compare the difference in flexural behavior of RC Beams, limited tests were conducted under different types of Longitudinal steel ratio and freeze-thawing cycles. For this purpose, fourteen small-scale RC beams ($100mm{\times} 100mm {\times}600mm$) were strengthened in monotonic and cyclic loadings, subjected to up to 150, 300 cycles freeze-thawing from $-18{\sim}4^{\circ}C$. It is thought that experimental results will be used as basic data to evaluate flexural behavior of RC beams exposed to freeze-thawing.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.6
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• pp.73-81
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• 2012

Concrete structures are commonly exposed to freezing-thawing condition. This freezing-thawing action changes the pore structure of concrete, and it can reduce the durability of concrete. In this study, the change of the internal pore structure and durability of concrete due to freezing-thawing action are investigated. According to results, the excellent durability records were reported by the existing evaluation methods for all mixes. However, the pores, 50~100nm size in diameter, are increased in concrete specimens exposed to freezing-thawing action, and the chloride penetration resistance was significantly reduced. The linear relationship between pore structure and chloride penetration resistance was shown in water cured concrete. Meanwhile, the linear relationship was decreased when concrete is exposed to freezing-thawing condition. It is desirable to review the criterion of durability evaluation for concrete specimens exposed to freezing-fthawing and chloride attack condition, simultaneously.

• Korean Journal of Plant Resources
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• v.17 no.2
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• pp.75-81
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• 2004

This study was conducted to investigate effects of cryopreservation by vitrification on the seed germination rate and growth and physiological properties of seedlings of Maackia amurensis. Cryopreservation significantly decreased the germination rate of seeds of M. amurensis, but the reduction of germination rate was mitigated by the treatment of cryoprotectant (plant vitrification solution, PVS2) before plugging into liquid nitrogen and fast thawing rate after cryopreservation. Long-term PVS2 exposure decreased seed germination rate, whereas cryopreservation time didn't have influence on seed germination rate. In addition, growth and physiological properties of seedlings were not affected by PVS2 exposing time and cryopreservation time. Therefore cryopreservation could be widely used as a technique of long-term ex situ conservation without any damage and deterioration of cells or tissues of the forest seeds. However, in order to increase the effect of cryopreservation, we have to develope the lower toxic cryoprotectant and suitable techniques to the structural or chemical properties of a variety of seeds.

• Journal of the Korean Geosynthetics Society
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• v.10 no.2
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• pp.29-34
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• 2011

The purpose of this study was to prevent spreading of contaminants from movement of underground water by creating a barrier using artificial freezing method on a soil contaminated by oils and various DNAPLs. Specimens with 80% and 90% degrees of saturation were prepared to form freezing barrier using artificial freezing method. As the results of freezing specimen within soil bin with artificial ground freezing system, artificial contaminated soil cut off wall formed the thinnest wall after 12 hours. It is judged that this cut off wall will control the second soil pollution by intercepting expansion and movement of pollutants and DNAPLs within artificial contaminated soil cut off wall by underground water, intercepting inflow or outflow of underground water. Cut off walls formed by artificial ground freezing system had each other freezing speed according to degree of saturation.

• Food Science of Animal Resources
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• v.20 no.3
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• pp.222-229
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• 2000

본 연구는 동결 및 재동결 처리가 계육의 부위별 품질특성에 미치는 영향을 검토하기 위해 서 실시하였다. 드립감량은 동결육이 재동결육보다 낮았으며, 가슴육이 다리 및 날개육보다 높았다. 가열감량은 재동결육, 동결육 및 신선육의 순으로 높게 나타났다. L, a 및 b 값은 동결에 의한 차이는 없었으나, L 값은 가슴육이 다리 및 날개육이 가슴육보다 높았다. 수용성 단백질 추출성의 신선육 및 동결육이 재동결육보다 높았으며 , 다리 및 날개육이 가슴육보다 높았다. 염용성 단백질 추출성의 경우, 신선육, 동결육 및 재동결육의 순으로 높았고, 가슴육이 다리 및 날개육보다 높았다. 보수력은 신선육, 동결육 및 재동결육의 순으로 우수하였고, 부위별로는 다리, 날개 및 가슴육의 순이었다. 신선육 및 동결육의 pH는 재동결육보다 낮았으며 다리 및 날개육이 가슴육보다 높았다. TBA 및 VBN은 재동결육, 동결육 및 신선육의 순으로 높았고, 다리 및 날개육의 TBA는 가슴육보다 높았으나, VBN은 낮은 편이었다. 기호성은 신선육이 재동결육보다 우수하였고, 부위별로는 다리 및 날개육이 가슴육보다 우수하였다.

• Food Science and Preservation
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• v.21 no.3
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• pp.341-349
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• 2014

The antioxidative effect and quality characteristics of different drying methods (hot air drying, far-infrared radiation drying, vacuum freeze drying) from Schizandra Chinensis Baillon were investigated. The moisture contents and water activity(Aw) contents each 4.46% and 0.38 values of the vacuum freeze drying were lower than those of other samples. A significant not difference in pH values occurred in all samples (p<0.05). The highest content $^{\circ}brix$ vacuum freeze drying was $6.60^{\circ}Brix$ respectively. The turbidity values of the samples were hot air drying 8.24 T%, far infrared radiation drying 0.32 T%, vacuum freeze drying 71.85 T%. The Hunter's L, a and b values of vacuum freeze drying were higher than those of other samples. The order of the free sugar content was glucose>fructose>sucrose, and that of the total free sugar contents were vacuum freeze drying (6.33 g/100 g) > far infrared drying (5.01 g/100 g) > hot air drying (3.73 g/100g). Antioxidant acitivy (DPPH radical scavenging, ABTS radical scavenging) and total phenol, total flavonoid, and total tannin content was highest in vaccum freeze drying than other different drying methods except nitrite scavenging ability.

• Korean Journal of Food Science and Technology
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• v.38 no.4
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• pp.506-512
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• 2006

We investigated changes in the physicochemical characteristics and functional components of the Saengsik cereal grains-milled rice, brown rice, glutinous rice, and barley- by washing with electrolyzed water. There were no changes in the composition of all cereal grains that was dried with hot-air and freeze-dried after being washed with electrolyzed water. The L and a values were not affected by drying in milled rice, brown rice, glutinous rice, or barley, but the b value increased in milled rice and glutinous rice-this increase was greater with hot-air drying than with freeze-drying. The dietary fiber content of the all cereals increased with hot-air drying. The niacin content decreased in all cereals; the extent of this change was greater with hot-air drying than with freeze-drying. The ${\beta}-glucan$ content of barley was higher in samples that underwent freeze-drying than in those treated by hot-air drying, but was not affected by washing with electrolyzed water. Thus, other than a change in color for milled and glutinous rice, no changes in the physicochemical characteristics and functional components these products were observed with freeze-drying. Data indicate that the electrolyzed water washing could be effectively used as pasteurization step in the uncooked cereal grains.