• Journal of Veterinary Clinics
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• v.11 no.2
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• pp.545-552
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• 1994

This experiment was carried out to investigate the renditions to maintain good post-thaw motility and viability of canine spermatozoa when the semen was frozen using methanol. The semen from two male dogs which had been proven to be fertile in the previous one year was treated with different compositions of semen diluent and was frozen at different freezing temperatures, When canine semen was frozen at-2$0^{\circ}C$, -6$0^{\circ}C$, or -8$0^{\circ}C$, the spermatozoa frozen and stored at -2$0^{\circ}C$ showed very low post-thaw motility and viability from day 2 to 7 and showed no viability since day 15 after freezing. The spermatozoa frozen and stored at -6$0^{\circ}C$ or -8$0^{\circ}C$ showed higher post-thaw motility and viability on day 2, 1, 15 and 30 after freezing than that frozen and stored at-2$0^{\circ}C$(p<0.01), with no difference between two groups. Among different composition groups of the semen diluents of control(tris + egg yolk + glycerol), egg yolk-free, 히ycerol-free, and tris-free, Prior to freezing, the egg yolk-free diluent showed significantly love. motility and viability than the other diluents(p<0.05). On each thawing day (from day 2 to 15 after freezing), control group showed considerably higher motility and viability than the other groups(p<0.01). The canine spermatozoa frozen and stored at -6$0^{\circ}C$ and -8$0^{\circ}C$ showed gradual decrease of motility from day 2 to 30 after freezing and the spermatozoa of these two groups thawed on day 30 showed considerably love. motility than those thawed on day 2 after freezing, respectively(p<0.01). These results indicate that the freezing temperature of either -6$0^{\circ}C$ or -8$0^{\circ}C$ can be applicable to the freezing method using methanol and also all of the components of the semen diluent including cryoprotectant, buffer and cold-shock buffer are very important to maintain motility and viability of canine spermatozoa in the freezing and thawing procedure.

• Journal of The Korean Society of Agricultural Engineers
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• v.52 no.1
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• pp.51-59
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• 2010

The cemented sand and gravel (CSG) method is a construction technique that adds cement and water to rock-like materials, such as rivered gravel or excavation muck which that can be obtained easily at areas adjacent to dam sites. This study was performed to evaluate the unconfined compressive strength properties and freezing and thawing resistance of CSG materials with unit cement content. The three types of CSG-80, CSG-100 and CSG-120 with cement content were designed to evaluate the optimum water content, dry density, strength, stress-strain, micro structure and durability factor. As the results, the optimum water content ratio with cement content showed almost similar tendency, and the unconfined compressive strength and dry density increased as cement content increases. The strength ratio of 7 days for 28 days were in the range of 55~61 % and the strain ratio in stress-strain curve were in the range of 0.8~1.6 % nearby maximum strength in 28 days. It is expected that this study will contribute to increasing application of CSG method as well as to increasing the utilizing of CSG materials as a environmentally friendly CSG method.

• Journal of Embryo Transfer
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• v.26 no.3
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• pp.201-207
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• 2011

The present study was performed to investigate the survival and subsequent embryonic developmental rate of immature and mature oocytes after vitrification and pronuclear stage embryos after slow-freezing and vitrification. We have also tried to examine the dependency of concentrations (7.5, 15%) and exposure time (5, 10, 20 min) of ED cryoprotectant on developmental rate of pronuclear stage embryos. The developmental rates of 2-ce1l and blastocyst embryos at mature oocytes were significantly (p<0.05) higher than immature oocytes. After slow freezing, vitrification and thawing of pronuclear stage embryo, the survival and developmental rates of blastocysts and hatched blastocysts were significantly (p<0.05) higher after vitrification than after slow-freezing. On contrary, the developmental rates of 2-cell embryos were significantly (p<0.05) higher after slow freezing than after vitrification. The cryopreservation methods of pronuclear stage embryos vitrified by exposed to 7.5% ED solution for 5 minutes was significantly (p<0.05) higher than other experimental group. The results of our study suggest 1hat the developmental rates of mature oocytes have been more successful than immature oocytes during vitrification. Vitrification was more efficient than slow freezing in case of pronuclear stage embryos. The effective cryopreservation method of pronuclear stage embryos was vitrified by exposed to 7.5% ED solution for 5 minutes.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.s02
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• pp.96-114
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• 1989

There are several meterorolgical stresses in the winter cereal crops. Among these stresses, cold injury is one of the most important stresses for wheat and barley production in Korea. The reduction in grain yield of the wheat and barley due to cold injury has occurred almost every year in Korea. The objective of the study was to get the basic information in relation to the cold injury and to detect the method minimizing the damage of cold injury. When the air temperature was the ranges of -13$^{\circ}C$ to -15$^{\circ}C$, the soil temperature at the crown part of the plant was very stable, whereas in the ranges of -2$^{\circ}C$ to -3$^{\circ}C$ the soil surface temperature was more unstable and cold than air and subterranean temperatures. The different parts of the plant in wheat and barley possess the different levels of cold hardiness. In comparison to the cold hardiness of plant parts, the leaf and crown are the less sensitive to cold injury than root and vascular transitional zone. The type and extent of stress is determined by the redistribution pattern of water during freezing. These types from freezing processes were three types: a) Equilibrium freezing pattern b) Non -equilibrium freezing pattern, c) Non-equilibrium freezing pattern typical of tender tissues. Cold hardiness in wheat plants were more harder than barley plants at vegitative stage, but inverted at the reproductive stage. Injuries by low temperature during the seasons of barley cultivation in Korea were occured mainly in four stage; in the first and third stage, frost injury occurs, the second stage, freezing injury, and the fourth stage, chilling injury.

• Journal of Embryo Transfer
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• v.22 no.4
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• pp.251-255
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• 2007

This study was carried out to examine on developmental competence of Hanwoo embryos cultured in vitro according to culture conditions and freezing methods. The in vitro developmental competence to blastocyst stage at Day 8 of culture in SOF was significantly (p<0.05) higher than that in CR1aa (30.3% vs. 18.4%). The in vitro developmental rate of morula and blastocysts cultured in group culture was significantly (p<0.05) higher than that in individual culture (41.4% and 36.0% vs. 21.1% and 10.5%, respectively). The cell number of Day 8 blastocysts in group culture was significantly (p<0.05) higher than that in the individual culture ($120.1{\pm}12.8\;vs.\;94.1{\pm}12.1$, respectively). The survival rates of frozen-thawed balstocysts that were exposed in 1.5 M ethylene glycol or 1.5 M ethylene glycol containing 0.1 M sucrose were 77.5% and 78.7%, respectively. The survival rates of blastocysts cultured for 48 h in slow freezing and vitrification was not significantly different (73.3 and 74.0%). In conclusion, in vitro developmental competence of bovine embryos was influenced on the culture medium (SOF) and culture method (Group culture). Survival rate of frozen-thawed of bovine embryos was not influenced on freezing solutions and freezing methods.

• Journal of Energy Engineering
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• v.26 no.3
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• pp.105-112
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• 2017

A lot of piping systems have been used from nuclear power systems to water supply systems. The maintenance of the piping systems is needed to ensure proper operation of the piping systems. Failure of the large pipe systems especially such as KDHC(Korea District Heating Corporation) can be a matter directly related to the enterprise productivity and profitability. It can also lead to very important issues in promoting public safety and convenience. Therefore a method of quick and safety repairs have been emerged as the most important problem. In this study, freezing seal isolation method using liquid nitrogen cryogenic refrigerant was developed for the maintenance of a pre insulated heat transport pipe of KDHC with a diameter of 300 mm. In this study, by employing computational analysis techniques we performed the flow and heat transfer analysis for the targeted pre insulated heat transfer pipe and freezing seal jacket(ice-Plug) and have selected for optimal system. The detailed design model based on the results of the computational analysis finally was produced. A laboratory-scale test apparatus were designed and the freezing seal isolation self-test carried out. Also the performance assessment tests in the test bed of KDHC were carried out for on-site application.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.2
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• pp.424-435
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• 1991

To develop the photoelastic experiment method for the orthotropic material under pure torsional moment is the main objective of this research. In the development of photoelastic experiment for orthotropic material under pure torsional moment, the important problems and their solutions are the same as following. In the model material for photoelastic experiment, it was found that C.F.E.C.(Copper Fiber Epoxy Composite) can be used as the model material of photoelastic experiment for orthotropic material. In the stress freezing cycle, it was assured that stress freezing cycle for epoxy can be used as the stress freezing cycle of the photoelastic experiment for orthotropic material. In the slicing method, it was found that the negative oblique slicing method can be effectively used as slicing method in 3-dimensional photoelastic experiment. In the measuring method of stress fringe values and physical properties in the high temperature, it was found that stress fringe values can be directly measured by experiment and physical properties can be directly or indirectly by equation between stress fringe values and physical properties developed by author. In the stress analysis method of orthotropic material under pure torsional moment by photoelastic experiment, it will be studied in the second paper.

• Clinical and Experimental Reproductive Medicine
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• v.27 no.1
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• pp.67-74
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• 2000

Objective: This study was conducted to investigate the effect of vitrification on the implantation and the pregnancy of human blastocysts. Method: The transfer of the frozen-thawed blastocysts by the slow freezing or vitrification was performed between January 1998 and July 1999. The zygotes derives from IVF were cocultured with cumulus cells in YS medium containing 20% hFF for 5days. Two or three of the best balstocysts produced on day 5 were transferred into the uterus, and then supernumerary blastocysts were randomly divided into two groups. One was frozen by slow freezing and the other was frozen by vitrification method. The slow freezing procedure was performed in two steps (5% glycerol and 9% glycerol + 0.2 M sucrose for 10 min, respectively) using programmed freezer ($-2^{\circ}C$/min to $-7^{\circ}C$, manual seeding at $-7^{\circ}C$, $-0.3^{\circ}C$/min to $-38^{\circ}C$ and plunged into $LN_{2}$). The blastocysts frozen by slow freezing were thawed at $36^{\circ}C$ then removed glycerol in 7 steps. The vitrification procedure was performed in three steps (10% glycerol for 5 min, 10% glycerol + 20% ethylene glycol for 5 min, 25% glycerol + 25% ethylene glycol and directly $LN_{2}$ within 1 min). The blastocysts frozen by vitrification were thawed at $20^{\circ}C$ water then removed cryoprotectant in 3 steps. In each group, thawed blastocysts were cocultured with cumulus cells in YS medium containing 20% hFF for 18h and transferred into the uterus. The implantation rate was evaluated per transferred blastocysts and the pregnancy rate was evaluated per transfers. Results: The survival rate of vitrified group (74.5%) was higher than slow freezing group (68.0%), but not significant. When 98 thawed blastocysts of vitrification were transferred in 40 cycles, 19 pregnancies (clinical pregnancy rate; 47.5%) were established. One miscarriage occurred in the eighth week of pregnancy (ongoing pregnancy rate; 45.0%). 7 pregnancies were ongoing, 11 pregnancies went to term, and 16 healthy infants were born. The Implantation rate was 31.6%. These results were higher than those obtained by the slow freezing (clinical pregnancy rate; 40.3%, ongoing pregnancy rate; 32.5% and implantation rate; 25.3%), but not significant. Conclusion: Vitrification is a simple, quick and economical method when compared to slow freezing. It will be chosen as a good method of human embryo freezing in IVF-ET programs.

• Korean Journal of Animal Reproduction
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• v.23 no.2
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• pp.165-174
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• 1999

Boar semen can be frozen successfully. However, there is a large variability in the extent of damage boar semen samples experiences during cryopreservation. This experiment was undertaken to find out factors that affect a post-thaw viability of boar spermatozoa. For this purpose, cryodiluents(BF5, LEY, Soejima and M-Soejima), cryoprotectants(glycerol. ethylene glycol, and propylene glycol), pre-freezing method(dryice-pellet, dryice-straw and L$N_2$vapour-st-raw) and total time required for freezing(2. 5, and 7 h) were compared as a factors. To investigate quality of semen during freezing process, motility(%), normal apical ridges(%, NAR), and proportion of living sperm(%) by flow cytometic analysis were assessed after collection, cooled, pre-frozen and post-thawing. Post-thaw motility of semen diluted with M-Soejima was 52.0%, respectively. When heparin, caffeine or heparin＋caffeine was added to 2nd cryodiluent of M-Soejima during freezing process, the highest motility after thawing was shown at the addition of caffeine (2mM), with 61.7$\pm$2.9% of motility. M-Soejima with heparin or caffeine was significantly higher than that of controI(p＜0.05). The result using glycerol(Gly), ethylene glycol(EG), propylene glycol(PG), and their mixture (Gly＋EG and Gly＋PG) as cryoprotectants, the highest motility was shown at the mixture treatment with Gly plus PG. However, the highest proportion of live spermatozoa was shown at Gly＋EG, there was no significantly difference among treatments(p＞0.05). When semen was pre-frozen with three manners(dryice-pellet, dryice-straw, and L$N_2$ vapor-straw), motility(%) of post-thaw spermatozoa was the highest in the L$N_2$ vapor-straw pre-freezing method of M-Soejima cryodiluent with 57.5% of motility, For a simple, economical and timesaving approach to freezing boar semen, total time required for freezing were 2, 5, and 7 hours, post-thaw motility were 43.8, 45.0 and 38.8%, NAR were 19.5, 22.7 and 28.5%, and viability were 20.8, 19.9 and 22.1%, respectively. This data suggests that boar semen diluted with M-Soejima cryodiluent contained caffeine, using mixture of glycerol and propylene glycol or ethylene glycol as cryoprotectants, frozen with 2 hours, can be taken better motility, NAR, and proportion of live spermatozoa.

• Korean Journal of Food Science and Technology
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• v.30 no.2
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• pp.341-347
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• 1998

To develop simple and accurate analytical method for freezing time prediction of beef and tylose under various freezing conditions, freezing time (Y) was regressed against the reciprocal $(X_3)$ of difference of initial freezing point and freezing medium temperature, reciprocal $(X_4)$ of surface heat transfer coefficient, the initial temperature $(X_1)$ and thickness $(X_2)$ of samples which should cover most situations arising in frozen food industry. As results of the multiple regression analysis, equations were obtained as follows. $Y_{tylose}=3.45X_1+7642.84X_2+4642.67X_3+2946.89X_4-431.33\;(R^2=0.9568)$ and $Y_{beef}=0.68X_1+7568.98X_2+2430.78X_3+3293.26X_4-299.00\;(R^2=0.9897)$. These equations offered better results than Plank, Nagaoka and Pham's models, shown in satisfactory agreement with models of Cleland & Earle and Hung & Thompson when were compared to previous models, and the accuracy of its was very high as average absolute difference of about 10% in the difference between the fitted and experimental results. Also, thermal diffusivities of beef and tylose were measured as $4.43{\times}10^{-4}m^2/hr$ and $4.39{\times}10^{-4}m^2/hr$ at $6{\sim}7^{\circ}C$, $2.42{\times}10^{-3}m^2/hr$ and $3.32{\times}10^{-3}m^2/hr$ at $-10{\sim}-12^{\circ}C$. Initial freezing points of beef and tylose were $-1.2^{\circ}C\;and\;-0.6^{\circ}C$, respectively. Surface heat transfer coefficients were estimated $20.57\;W/m^2^{\circ}C$ with no-packing, $16.11\;W/m^2^{\circ}C$ with wrap packing and $13.07\;W/m^2^{\circ}C$ with Al-foil packing, and the cooling rate of immersion freezing method was about 10 times faster than that of air blast freezing method.