• Journal of Embryo Transfer
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• v.28 no.3
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• pp.297-302
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• 2013

Cryopreservation of epididymal spermatozoa offers a potential tool for rescuing genetic material from males of genetically elite populations. Castration, catastrophic injury, sudden death or any other event that makes semen collection or mating impossible may prematurely terminate a stallion reproduction. Stallion epididymal spermatozoa vary widely in the loss of progressive motility, acrosomal integrity, and viability during freezing and thawing. The objective of this work was to investigate the effect of (1) freezing package types on cryopreservation efficiency, (2) thawing temperatures (37, 56 or $70^{\circ}C$) on Computer Assisted Sperm Analysis (CASA) parameters and (3) post-thawing incubation time (0, 1, 2 or 4h) on castrated stallion epididymis. Post-thawed sperm motility ranged between 59.69% and 64.28% ($56^{\circ}C$ and $37^{\circ}C$) in various thawing temperatures. When stallion epididymis sperm was frozen, straw was better than freezing tube on VCL (Velocity of Curvilinear Line) and VAP (Velocity of Average Path) parameter. Higher percentage of motility was observed at $37^{\circ}C$ thawing temperature even though no significant difference was observed among various temperatures. The motility, VCL, ALH (Amplitude of Lateral Head displacement), VAP, BCF (Beat-Cross Frequency) and STR (Straightness index) parameter of post-thawed sperm were significantly decreased by increasing the incubation time for all thawing temperatures. The present study showed that type of freezing package (Straw vs. Freezing tube) was not significantly different on cryopreservation efficiency. Furthermore, stallion epididymal spermatozoa frozen-thawed at $37^{\circ}C$ for 1 min resulted the highest proportion of motility and velocity movement. In addition, motility and viability of frozen-thawed stallion epididymal spermatozoa were also decreased by incubation.

• Food Science and Preservation
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• v.6 no.4
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• pp.398-401
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• 1999

This study was conducted to investigate the changes in qualities of soft persimmon by freezing and defrosting. Testing varieties were Sangjudungsi and Chunsdobansi that were cultivated on Sangju and Chungdo regions, chief cultivation of astringent persimmon in Kyongbuk province. Dropping time to 40 degrees below zero of the flesh was 10∼20 minutes longer in Chungdobansi than that in Sangiudungsi. Freezing temperature of astringent persimmon was 2∼3 degrees below zero. Occurence rates of cracked fruit during freezing storage were 24.5% in Sangjudungsi and 15.5% in Chungdobansi. Defrosting of Sangjudungsi and Chungdobansi took 150 minutes and 120 minutes at 5$^{\circ}C$, respectively. L values of chromaticity were some lower after defrosting than that of frozen soft persimmon, and a and b values decreased during defrosting rapidly. Soluble solid contents of frozen soft persimmon almost didn't change during freezing, that is, harvesting, softening, frosting and defrosting steps. Defrosting completion time to core part took 4 hours and 30 minutes in Sangjudungsi and 4 hours and 20 minutes in Chungdobansi at ordinary temperature (10.9∼14.8$^{\circ}C$).

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.6
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• pp.957-972
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• 2018

Tunnels constructed in cold regions can cause serious defects such as cracks and leaks due to external temperature changes in the portals and vents. In order to prevent the freezing damage of the tunnel, appropriate measures should be applied to the section where the freeze damage is concerned. However, the specific criteria and contents for judging whether or not the anti-freeze measures are applied are not presented. In this study, the laboratory freezing tests on the temperature changes of the concrete specimens under freezing conditions were carried out. And the freeze-thaw repetition cycle (F), which can judge the possibility of freezing damage, were presented based on the heat transfer quantity (W) by experimental results of case studies. Also, we propose a classification of cold regions considering the climatic characteristics of Korea for using it to efficient design and maintenance.

• Journal of the Korea Concrete Institute
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• v.14 no.6
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• pp.942-948
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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 the strength development may be delayed. One of the solution methods to resolve these problems is to reduce freezing temperature of concrete by the use of chemical admixture called Accelerator for freeze protection. In this study we Investigate the effect on the strength development of cement mortar using accelerator for freeze protection with the variable curing condition. As the result of this study, the mortar using accelerator for freeze protection show continuously the strength development in curing condition of -5$^{\circ}C$. And the compressive strength under variable temperature condition was higher than constant temperature condition in same maturity.

• Journal of Bio-Environment Control
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• v.16 no.3
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• pp.269-273
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• 2007

Freezing hardiness of winter bud and branch according to dormancy level and low temperature, in persimmon (Diospyros kaki) cultivars, was investigated by electrolyte leaching rate, triphenyltetrazolium chloride (TTC) test, and sprouting. Electrolyte leaching rate was lowest in branch of 20th January and was highest in the 20th March. The electrolyte leaching rate of 'Fuyu' and 'Cheongdobansi' was high in the 20th January and was low in the 20th February, but 'Uenishiwase' and 'Nishimurawase' was opposed to that. 'Hachiva' was the middle level in the cultivars. Absence rate by TTC test was highest in the 20th January and was low in the others. The 20th March had a great decrease in $-10^{\circ}C$ treatment. The absence rate of 'Fuyu' and 'Uenishiwase' was low in the 20th January and March and was high in the 20th February. 'Nishimurawase' and 'Hachiya' had a high level irrespective of dormancy level. Sprouting was highest in the 20th February and was lowest in 20th March. Most cultivars were not sprout in $-20^{\circ}C$ treatment and 'Fuyu', 'Nishimurawase' and 'Cheongdobansi' was a little high level irrespective of dormancy level. 'Hachiya' was only high in the 20th January. Thus, freezing hardiness of persimmon was very weak low temperature after dormancy breaking and was not different between astringent and non-astringent persimmon.

• Current Research on Agriculture and Life Sciences
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• v.6
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• pp.163-169
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• 1988

This study was conducted to predict the density changes according to concentration and temperature changes under freezing point. This information is needed for the design of freezing equipment and for the efficient utilization of refrigerating system. Orange juice, Apple juice, Grape juice and Sucrose solution were used for the measurement of density in this study at the temperature range from $-5^{\circ}C$ to $-40^{\circ}C$ and at the concentration range from 10 to 40%. The unfrozen water fraction of samples was determined by Heldman's method. The density values were determined by measuring the weight of a frozen solution at each temperature with a known volume. Solutions were placed in the thick-walled aluminum tubes. When the solution was frozen the excess ice was removed with a razor until the surface of the ice was flush with the top of the aluminum tube. The tube and ice were weighted immediately. Knowing the volume, tare weight, and final weight, the density could be determined. With this procedure, the data of density and unfrozen water fraction for fruit juices and sucrose solution were collected. The density prediction models of fruit juices and sucrose solution under freezing point were established by the optimization computer program with measured experimental data.

• Journal of the Korean Data and Information Science Society
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• v.27 no.1
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• pp.67-74
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• 2016

Due to the character of the climate of Korea, the pavement of a road is Influenced by freezing in winter season and thawing in thawing season. In the last few years, several articles have been devoted to the study to minimize the damage of freezing and thawing action. The purpose of this paper is to identify appropriacy of factors that influence road pavement thickness. We conduct the decision tree analysis on the field data of road pavement. The target variable is 'Frost penetration'. This value was calculated from the temperature data. The input variables are 'Region', 'Type of road pavement', 'Anti-frost layer', 'Month' and 'Air temperature'. The region was divided into 9 regions by freezing index $350{\sim}450^{\circ}C{\cdot}day$, $450{\sim}550^{\circ}C{\cdot}day$, $550{\sim}650^{\circ}C{\cdot}day$. The type of road pavement has three-section such as area of cutting, boundary area of cutting and bankin, lower area of banking. As the result, the variables that influence 'Frost penetration' are Month, followed by anti-frost layer, air temperature and region.

• Korean Journal of Animal Reproduction
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• v.14 no.1
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• pp.9-16
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• 1990

This study was carried out in order to investigate effects of cryoprotectant concentration and equilibration time on survival of ultrarapidly frozen 2-cell mouse embryos. Mouse 2-cell embryos, following dehydration by exposure to DMSO and sucrose, were directly immersed into liquid nitrogen and thawed in 37$^{\circ}C$ water. Viability was defined by development rate to the blastocyst stage after in vitro culture for 72 hours. The results are summarized as follows ; 1. When 0.25M of sucrose was added into the freezing medium at various concentrations of DMSO and dilution medium, higher development rate of embryo was obtained in 3.0M DMSO concentrations (82.6%). However, when sucrose concentraitons of 0.25 and 0.5 M were added to the freezing medium with 3.0 M DMSO and dilution medium, development rate of embryos were 81.7% and 24.1%, respectively. 2. In the equilibration time at room temperature, higher development rate was attained after short period of time (2.5min) in 3.0 M DMSO＋0.25 M sucrose (85.9%). 3. The development rate of embryos at in vitro 2-cell, in vitro 2-cell, solution control and untreated control was 84.6%, 90.9%, 89.9%,, and 89.7%, respectively.

• Korean Journal of Animal Reproduction
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• v.13 no.1
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• pp.18-25
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• 1989

This study was carried out to investigate the general semen characteristics of the Korean native goat and the effect of temperature, incubation time, dilution rate, freezing rate and glycerol concentration on motility and NAR (normal apical ridge) acrosome of fresh and frozen Korean native goat spermatozoa. 1. Average semen volume per ejaculate, motility, concentration and pH of fresh Korean native goat spermatozoa were 0.19${\pm}$0.09 ml, 94.5${\pm}$0.47%, 26.17${\times}$108${\pm}$1.68/ml and 6.63${\pm}$0.18, respectively. 2. Motility and NAR acrosome of fresh spermatozoa during incubation were higher at 22$^{\circ}C$ than at 5$^{\circ}C$ or 37$^{\circ}C$(P<.01). 3. Motility and NAR acrosome of spermatozoa diluted 1:4 during incubation were higher at 22$^{\circ}C$ than at 5$^{\circ}C$ or 37$^{\circ}C$(P<.01). 4. Motility and NAR acrosome of spermatozoa during incubation were higher for samples diluted 1:1, 1:2, or 1:4 than for samples diluted 1:6(P<.01). 5. Motility and NAR acrosome of post-thaw spermatozoa were higher at freezing rate of 12$^{\circ}C$/min than at freezing rate of 1$^{\circ}C$/min or 24$^{\circ}C$/min when glycerol concentration was 9%(P<.01).

• Journal of Veterinary Clinics
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• v.4 no.2
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• pp.449-455
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• 1987

Quick freezing of bovine embryos was attempted after they were predehydrated at room temperature. Combined solutions of 2M glycerol or 2M ethylene glycol in the presence of either 0.5 or 1.0M sucrose in phosphated buffered saline+20% calf serum were compared. The quick freezing method in which embryos were directly transferred in liquid nitrogen vapor for 2 minutes at - l70$^{\circ}C$ before being plunged into liquid nitrogen was used. Post-thaw survival rates in 2M glycerol and 2M ethylene glycol were high with 0.5 M (55.6% and 53.3%) versus 1.0M(38.1% and 31.6%) sucrose(P < 0.05). But survival rates with 2M glycerol and 2M ethylene glycol were not significantly different. Transfer thawed embryos frozen with 2M glycerol and 2M ethylene glycol by 0.5M sucrose resulted in birthrates of 40.9% and 40.0%, respectively compared to 26.3% and 27.2%, respectively, for 1.0 M sucrose(p<0.05). This was 56.0% for fresh control.