• Journal of the Korean Society of Safety
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• v.33 no.3
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• pp.15-20
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• 2018

There have been a number of major fatal fire accidents in Korea recently. The number of fires in 2017 were 44,178, which is not only increasing number of fires but also increasing in casualties. Particularly, the fire at Jecheon Sports Center, which suffered many casualties, is expected to have a huge impact. The cause of the fire has not been determined yet, but heat waves on the ceiling have also been pointed out. As such, the copper heating waves, which are used as a preventive measure against damage of pipes due to freezing of pipes, etc., always have a fire hazard. To determine the possibility of a flame-resistant heated fire, a positive electric cable product was used to artificially ignite and analyze the results. In case of a short circuit, the external covering of the positive electric cable is damaged, but not short circuit unless the heating material surrounding the wire is damaged. Due to the characteristics of heating cable for preventing copper waves, the chances of insulation becoming more severe due to moisture and temperature changes are higher than normal wires. If the internal heating system is carbonized by insulating deterioration without damage to the outer coating, it is likely to cause trekking, to form a winding loop in the heating materials, and to cause short circuit in the heated materials. For the positive temperature line, if the middle is shorted, the current continues to flow to the short circuit unless the breaker disconnects. Consequently, a heated fire that does not cut off the power immediately may leave multiple marks or cuts.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.447-450
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• 1997

A new technique for the preparation of porous vascular prostheses was investigated. Polyurethane solution (10 to 14wt%) was injected into a mold. After freezing at low temperature $(0^{\circ}C\sim-40^{\circ}C)$, solvent was dissolved out with water at $0^{\circ}C$ to form porous tubes. The average pore size $(<10{\mu}m)$and pore occupation (10% to 51%) were easily changed by changing polyurethane concentration, freezing temperature, and freezing methods. This technique can give a proper pore size $(30\sim60{\mu}m)$ for tissue ingrowth, and suitable compliances for matching with arteries and veins. This method might give a desired compliant graft for artificial implantation with the presently valid medical polymers.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.3
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• pp.199-206
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• 1982

Histological changes occurred by freezing storage and subsequent thawing, and changes of muscle fiber after heating and drying of the eel (Anguilla japonica) were observed under microscope . The results are as follows : (1) After one month of freezing storage the muscular tissue produced considerable number of extracellular and intracellular ice crystals. The sample stored at the temperature of $-40^{\circ}C$ produced ice crystals inside the muscle cells while sample stored at $-20^{\circ}C$, outside. (2) No changes were observed in the hypodermic fat after thawing regardless of storage temperature, while insufficient recovering of muscle cells were detected in the muscular tissue. Muscular tissues which have been stored $-20^{\circ}C$ showed severe change in shape due to dehydration. (3) Microscopic observation on muscle homogenate showed loss of transparency due to free-zing, disfiguration and contraction by drying and water seperation, and elasticity by heating.

• Journal of the Korean Society of Food Science and Nutrition
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• v.19 no.4
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• pp.349-355
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• 1990

Actomyosine prepared from Yellowtail fish(seriola quinqueradiata) were stored at $0^{\circ}C$(ice-cooling) -3.5$^{\circ}C$(partial freeaing) and -2$0^{\circ}C$(freezing) Another actomyosin samples were prepared from the fish previously stored at the temperatures for a week as the maximum .Remaining activity of {{{{ {Ca }^{2+ } }}}}-and {{{{ {Mg }^{2+ } }}}}- dependent adenosine triphosphatase(ATPase) activity was measured fronm the actomyosin preparations. Specific activity of {{{{ {Mg }^{2+ } }}}}-ATPase of actomy-osin before storagew was 0.253$\mu$ mole pi/min/mg of protein and it was 1.5 times higher than that of {{{{ {Ca }^{2+ } }}}} -ATPase. The enzyme activities were markedly decreased during early period of storage. However no significant differences in the enzyme activity were revealed among the samples stored at different temperature. The enzyme of actomyosin prepared from the fish previously stored at the temperatures for a week revealed an acitivity of 2-3 times higher than that of freezing. Apparent denaturation constant of {{{{ {Mg }^{2+ } }}}} -ATPase of actomyosin was between 0.810-1.139 per day and it was about 1.5 times hgiher than that of {{{{ {Ca }^{2+ } }}}} -ATPase. But the constant of {{{{ {Mg }^{2+ } }}}} ATPase of actomyosin extracted from the fist stored for a week at each temperature was between 0.176-0.356 per day. This constant was 4 times higher than that of {{{{ {Ca }^{2+ } }}}}- ATPase in frozen stored fish. It was presumed from these results that denaturation of ATPase is largely accorded to the structural changes of actomyosin.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.4
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• pp.296-302
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• 2001

Winter cereals are acclimated during wintering, and thereafter their freezing resistance is increased. In order to analyze inheritance and heritabilities for photoinhibition of photosynthesis by high light intensity under low temperature, and to evaluate the relationship between low temperature-induced photoinhibition and winter survival, 4 parental half diallel crosses were used. The detached leaves of 7-8cm long from plants grown for 35 and 55 days were placed on wet filter paper and placed in trays at 5$^{\circ}C$ cold room with 1,200 $\mu$mol $m^{-2}$ $s^{-1}$ PPFD. Chlorophyll fluorescence was measured with a chlorophyll fluorescence system after dark adaptation for 30 min. The Fv/Fm of 35day old plants was reduced from 0.714 in the control leaves to 0.409 and 0.368 following photoinhibitory treatment of 6h and 8h and the CVs were increased from 0.8% to 22.2-22.3%. The Fv/Fm of 55-day old plants was reduced from 0.775 in the control leaves to 0.485 and 0.439 following photoinhibitory treatment of 10h and 12h, respectively. According to half diallel cross analysis, Reno and Dongbori 1 (highly resistant to photoinhibition) was dominant, but Oweolbori (susceptible to photoinhibition) was recessive, and photoinhibition showed partial dominance with highly additive gene action. Dongbori 1 showed the greatest GCA effects for photoinhibition, and GCA/SCA ratios (8.7-22.3 times) indicated that the additive variance for the character was more important. Winter survival in barley crosses was positively correlated with resistance to photoinhibition and significantly fitted by linear regression ($R^2$=0.751$^{**}$-0.779$^{**}$). The chlorophyll fluorescence measured by Fv/Fm has been found to be highly inheritable and very useful in evaluating relative levels of freezing resistance in barley.ley.

• Applied Chemistry for Engineering
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• v.1 no.1
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• pp.23-29
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• 1990

The effect of a rapid freeze pretreatment of organic ion exchange resins on their grinding properties was studied. It was found that the structure of ion exchange resins was defected by freezing pressure formed in the process of rapid freezing. The defected resins didn't recover their own structure after thawing and those could be easy to be broken at room temperature by small force. Therefore, organic ion exchange resins could be ground readily at room temperature after rapid-freezing the fully swelled resins using by solid carbon dioxide, or liquid nitrogen. The rapid freeze pretreatment of cation exchange resins was very effective on grinding in particular. However, the effect of the pretreatment of anion exchange resins on grinding was less than that of cation exchange resins. In case of anion exchange resins, the ionic form of affected the grindability remarkably.

• Journal of the Korean Geosynthetics Society
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• v.12 no.3
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• pp.23-29
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• 2013

The mechanical behavior of frozen soils is different from that of unfrozen soils due to the phase change between water and ice. The strength characteristics of frozen soils are governed by the intrinsic material properties such as grain size, ice and water content, air bubbles, and by externally imposed testing conditions such as temperature, freezing time, and strain rate. Especially, the strength of the frozen soils is generally higher than that of unfrozen soils due to ice binding capacity with soil particles, and is strongly affected by a highly complex interaction between the solid soil skeleton and the pore matrix, composed of ice and unfrozen water. In this study, the direct shear test and unconfined compression test are carried out inside of a large-scaled freezing chamber, and the relationships between cohesion and unconfined compression strength under various freezing temperature conditions are discussed.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.8
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• pp.1094-1097
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• 2007

Vibration at frequency of 20 Hz and 0.18 g of acceleration was applied to 600 g watery kimchi contained in a glass jar of 1 L at subfreezing temperature (-3 and $-6^{\circ}C$) and $10^{\circ}C$ in order to see its effect on freezing and fermentation behaviors, respectively. The vibration at the subfreezing temperature delayed the freezing process and contributed to maintaining small ice crystal slurry in subsequent frozen storage. The vibration at $10^{\circ}C$ accelerated the acid and carbon dioxide production from the watery kimchi, which may be beneficial in shortening ripening time and attaining fresh cool taste.

• Journal of Navigation and Port Research
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• v.37 no.2
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• pp.129-135
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• 2013

Recently, waste water treatment system is developed in small and middle size to get more economic advantage. Freeze concentration system has high thermodynamic efficiency and low energy consumption, can re-use purified water and cold energy obtained from ice. This study was experimentally performed to investigate pollution containment in frozen layer by cooling wall temperature, air-bubble flow methods, initial ice-lining thickness of frozen layer in NaCl aqueous solution and the representative heavy metals, Pb and Cr aqueous solution. As the result, a decrease in the cooling wall temperature bring a higher growth rate of ice front and the more solute was involved in frozen layer. The method to inject directly air-bubble into ice-liquid interface through ring shape nozzle gave high purity of ice compared to indirect method. Ice lining in 5mm thickness resulted in frozen layer with higher purity than 1mm thickness.

• Proceedings of the Korean Society of Crop Science Conference
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• 1996.05a
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• pp.76-77
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• 1996