• Clinical and Experimental Reproductive Medicine
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• 제28권3호
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• pp.191-198
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• 2001

Objective : This study was conducted to examine the effect of vitrification on the survival and in vitro development of mice 1-cell zygotes. Method: Effects of exposure to vitrification solution and vitrification, with different concentrations of the cryoprotectant solution, were examined. The 1-cell zygotes were also subjected to a slow freezing-thawing method to compare with vitrification method. Solution composed of ethylene glycol (6.0 M, 5.0 M, 4.0 M) and sucrose (1.0 M) were used as cryopropectant. The experiments employed the method loading the embryos on electron microscope grids. Results: I. The effects of exposure in vitrification solution. 1-cell zygotes were non-toxic at all concentrations of the vitrification solution showing the survival rate between 88.1% and 97.5%. Development into 2-cell was more successful in the higher concentrations of the vitrification solution. Therefore, higher concentrations of the vitirification solution do not seem to cause any problems in vitrification procedure. II. The effects of vitrification method. 1-cell zygotes showed the survival rate between 78.8% and 92.4%. The lowest and the highest survival rate was observed in the 6.0 M and 4.0 M vitrification solution, respectively. 2-cell development rates varied from 77.6% to 91.3%. Blastocyst development rate was shown highest in 5.0 M and the lowest in 4.0 M solution. Therefore, the highest 2-cell and blastocyst development rate was observed in 5.0 M solution. III. Comparison of vitrification and slow freezing-thawing method on 1-cell zygotes. This experiment showed that 1-cell zygotes had the highest survival and development rates in 5.0 M vitrification solution. Vitrified group of 1-cell zygotes, in the 5.0 M vitrification solution, were compared with the group processed in slow freezing-thawing method. The development rate into 2-cell and blastocyst as well as the survival rate were higher in the vitrified group than in the slowly freezed group. Conclusion: 1. The results demonstrate that the best cryoprotectant is a 5.0 M vitrification solution for 1-cell zygotes. 2. Vitrification method significantly increases the survival rate of the 1-cell zygote and its development into 2-cell and blastocyst. Equilibration and exposure time during the vitrification was remarkerbly short in this experiment. Total time, from the exposure to vitirification solution to storage in the liquid nitrogen, was taken only 90 seconds. In contrast, the slow freezing-thawing method have taken more than four hours. Taken together, we presume that the overall time used for the procedure contributes to the results as an important parameter. 3. The loading of 1-cell zygotes on the EM grid is technically more simple and takes less time than the straw or cryo vial method.

• Journal of Advanced Marine Engineering and Technology
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• 제21권5호
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• pp.527-534
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• 1997

Freezing of an aqueous sodium cWoride solution (Nacl- H20) saturating a packed bed with ini¬tial salt concentrations of 5, 10, 15(k by weight is investigated experimentally in a rectangular cav¬ity. The system was cooled from the top, bottom and a vertical side wall. For the freezing experi¬ments from below, there was little effect of the initial salt concentration throughout the freezing process, and the global freezing rate was not affected by the initial salt concentration. For the freezing from above, the size of the mush region decreased and the mushlliquid interface became flatter as the initial liquid concentration is decreased. For the freezing from vertical side wall, reheating of the mixture was intensified with an increase in the initial salt concentration. For Ci= 5%, supercooling was observed only at the early times of freezing process, but for Ci= 15% small supercooling was observed throughout the freezing process.

• 한국식품영양과학회지
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• 제21권2호
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• pp.207-212
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• 1992

식품의 동결장치 설계 및 최적조작조건의 설정을 위해 필요한 식품중의 온도분포, 동결시간, 동결계면의 이동속도의 측정을 위하여 기존의 모델과 3단계동결 모델(3단계 수치계산모델)을 식품에 적용한 결과는 대략 다음과 같다. 1. Neumann왜와 체적변화를 고려한 Neumann해는 물의 경우 거의 일치하여 동결에 따른 체적팽창은 큰 영향이 없으며, 중간상을 고려한 Weiner때가 Neumann해보다 빠른 냉각속도를 나타내었다. 2. 체적팽창을 고려한 Neumann해를 물, 2% 한천겔, 20% 젤라틴 겔, 돈육에 적용시킨 결과, 결합수의 영향을 무시할 수 있는 물과 2% 한천겔에 잘 적용되었다. 또한, 잠열분산형 모델인 Weiner 해에는 결합수가 각각 16%, 23%로 그 값이 상대적으로 높은 젤라틴 20%겔과 돈육에 잘 적용되었으며, 돈육의 경우 중간상은 $0^{\circ}C$~-7$^{\circ}C$로 고려 할 때 실측치와 잘 일치하였다. 3. 3단계동결모델을 이용한 수치 해석해를 물과 20% 제라틴겔에 적용시킨 결과, Neumann해가 Weiner해보다 양호한 적용성을 보였다. 4. 이상과 같은 3단계동결모델에 의한 수치해는 수분의 존재상태 및 과냉각현상등의 문제를 포함한 식품의 동결현상을 기술하기에 그 범용성과 정도가 높은 모델임이 판명되어 금후에 상기 연구를 바탕으로 초기온도와 동결매체온도의 변화에 따른 빙결정의 크기 및 동결시간과 최대빙결정생성대 통과시간의 상관관계를 추정할 수 있다면 식품의 동결중 동결장치의 설계 및 최적조작조건의 설정이 가능하리라 사료된다.

• 한국건축시공학회지
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• 제2권2호
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• pp.151-156
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• 2002

When fresh concrete is exposed to low temperature, the concrete may suffer frost damage due to freezing at early ages and strength development may be delayed. One of the solution methods for resolve these problems is to reduce freezing temperature of concrete by the use of chemical admixture called Accelerators for freezing resistance. In this study, we investigate the effect on strength development of cement mortar using accelerators for freezing resistance with the variance curing condition. As the result of this study, the mortar using accelerators for freezing resistance show that continuously strength development in curing condition of -5$^{\circ}C$. And compressive strength under the variance temperature condition was higher than constant temperature condition in same maturity.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2006년도 전기학술대회논문집
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• pp.51-52
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• 2006

This study was progressed on the freezing behavior of waste water in relation to freeze concentration method useful to waste water treatment system of small and middle size and which can re-use purified water. The object of this experiment is comparing a pollutant contain of the frozen layer and of an aqueous solution by cooling wall temperature, a flow field effect and a initial thickness of frozen layer.

• 한국컴퓨터그래픽스학회논문지
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• 제26권5호
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• pp.1-13
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• 2020

본 논문에서는 흐르는 물에 의해 빙결 시뮬레이션 되어 방향성이 있는 얼음 형태를 안정적으로 모델링 할 수 있는 새로운 방법을 제시한다. 제안하는 얼음 모델링 프레임워크는 빙결 시뮬레이션에서 중요한 얼음의 성장 방향에 점성이 있는 유체의 흐름을 고려한다. 물 시뮬레이션 해법은 암시적 비압축성 유체 시뮬레이션에 새로운 점성 기법을 적용한 방법을 이용하고, 얼음의 방향과 글레이즈(Glaze) 효과는 제안하는 비등방성한 빙결 해법을 이용한다. 물 입자가 얼음 입자로 상태변화하는 조건은 습도와 물의 흐름에 따른 새로운 에너지 함수에 따라 계산된다. 습도는 오브젝트 표면의 가상 수막(Virtual water film)으로 근사되며, 유체의 흐름은 얼음의 성장 방향을 가이드하기 위해 우리의 비등방성한 빙결 해법에 통합된다. 결과적으로 점성이 있는 물의 흐름 방향에 따라 글레이즈와 방향성 있는 빙결 시뮬레이션 결과를 안정적으로 보여준다.

• 한국식품저장유통학회지
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• 제7권1호
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• pp.57-62
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• 2000

Ginseng was stored at a temperature lower than the freezing point after a treatment of freezing point depressing agents to extend its freshness. Respiration rate at freezing point of ginseng, -1.7${\pm}$0.1$^{\circ}C$, was inhibited 92% and 97% compared with those stored at 5$^{\circ}C$or 20$^{\circ}C$ , respectively. Sorbitol solution chosen as a freezing point depressing agent lowered the freezing point of ginseng to about -3.0$^{\circ}C$. Ginsengs treated with the sorbitol solution and packaged with 0.06mm LDPE was stored at -2$^{\circ}C$ , and the quality change was then compared with ginsengs stored at 0$^{\circ}C$ and 5$^{\circ}C$. Weight loss of ginsengs stored at -2$^{\circ}C$ for 100days was 1.5%, which is about 2.6times less than those stored at 5$^{\circ}C$. However, there were no significant difference between the ginsengs stored at -2$^{\circ}C$ and at 0$^{\circ}C$(1.9%). Spoilage rate of the ginsengs was 100% after 50 days of storage at 5$^{\circ}C$ and 25% after 100days at 0$^{\circ}C$respectively. but that of ginsengs stored at -2$^{\circ}C$ was 13%, which was half than that of ginsengs stored at 0$^{\circ}C$. Firmness and amount of monoscaccharides in ginsengs were decreased during storage at 5 or 0$^{\circ}C$ but ginsengs stored at -2$^{\circ}C$ showed better firmness and an increase in monosaccharides such as fructose and glucose. From above, when ginseng treated with freezing pont depressing agents were stored at -2$^{\circ}C$, the shelf life was extended to 2 or 3 times longer than those that were stored at 5 or 0$^{\circ}C$, respectively.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.533-536
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• 2001

When fresh concrete is exposed to low temperature, the concrete may suffer frost damage due to freezing at early ages and strength development may be delayed. One of the solution methods for resolving these problems is to reduce freezing temperature of concrete by the use of chemical admixture called Accelerators for freezing resistance. In this study, we investigate the effect on strength development of cement mortar using accelerators for freezing resistance with the variance curing condition. As the result of this study, the mortar using accelerators for freezing resistance show that continuously strength development in curing condition of -5$^{\circ}C$. And compressive strength under the variance temperature condition was higher than fixed temperature condition in same maturity.

• 대한설비공학회지:설비저널
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• 제17권4호
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• pp.377-381
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• 1988

Effects of thermal resistance of mold during freezing processes have been investigated. Saturated liquid is chosen to present one-dimensional quasi-steady solution and this solution is compared with numerical solutions. Front tracking finite element method has been applied for the numerical solutions. Results show that mold should be considered as well as phase change material except the cases when the very thin mold with relatively high thermal conductivity is used.

• Journal of Advanced Marine Engineering and Technology
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• 제31권6호
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• pp.694-698
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• 2007

This present study has dealt with the effect of surfactant on the freezing of aqueous solution Sodium chloride aqueous solution was used to measure the effect of surfactant and the main parameters of this experiment were temperature of bath, revolution of stirrer. and the radial velocity of NaCl solution. The acquired main conclusions are as follows; 1) the lower super-cooling temperature make hardly to attach the ice on beaker, 2) the size of ice become smaller to add the surfactant, 3) the ice packing factor increase with increasing of stirrer revolution.