• Proceedings of the Korea Concrete Institute Conference
• /
• 2005.11a
• /
• pp.739-742
• /
• 2005

In this study, we predicted the service life against the freezing and thawing. as a result, we found that in the case of using the low quality crushed sand with high water-cement ratio, there is the possibility of deterioration. but in any other case, we concluded that there is no chance to deteriorate if we have the required air contents by using AE agent. we are going to improve the method to evaluate more exactly the durability of the concrete with crushed sand by acquiring data from the specimen which are exposed to field for long time.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2004.11a
• /
• pp.197-200
• /
• 2004

The increase of the use of recycled aggregate is necessary for the decrease of building waste, but it is not possible to use concrete because of the various range of quality. Therefore, the quality grade and application method of recycled aggregate should be prescribed before the site application so in that this study we investigated the effect of the quality of recycled aggregate on the compressive strength, resistance freezing and thawing. As results of this study, the compressive strength of recycled aggregate concrete used recycled aggregate, as if it had high quality recycled aggregate is similar or higher to that of crushed stone. Also, this high quality recycled aggregate affect the increase of resistance freezing and thawing.

• Food Science and Preservation
• /
• v.19 no.2
• /
• pp.201-208
• /
• 2012

The sensory properties of $Kalopanax$ $pictus$ and $Cedrela$ $sinensis$ shoots were analyzed according to their blanching conditions and the thawing methods used. For the Hunter colors, the $K.$ $pictus$ that was blanched without adding salt for 6 min had the highest L value, and the $C.$ $sinensis$ that was blanched with 1% salt for 6 min had the highest L value. The chlorophyll content of $K.$ $pictus$ was 141.1 mg% when it was blanched for 3 min with 2% salt, and the chlorophyll content of $C.$ $sinensis$ that was blanched without adding salt for 6 min was highest (124.8 mg%). When $K.$ $pictus$ and $C.$ $sinensis$ were blanched without salt addition for 3 min, their texture showed a higher value than that of the other samples. The sensory test result showed the highest overall preference for the sample that was blanched without adding salt for 3 min, among all the samples. The L value of the $K.$ $pictus$ that was thawed in a microwave oven was significantly higher than that of the other samples, but the L value of the $C.$ $sinensis$ that was thawed at $4^{\circ}C$ was higher than that of the other samples. As for the overall preference for the samples according to the thawing method used, $K.$ $pictus$ and $C.$ $sinensis$ scored highest in the case of thawing in a microwave oven.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2001.11a
• /
• pp.22-27
• /
• 2001

The purpose of this study is development of dry floor tile method that practically used for improving wet method's defect, with resin mat design. PE resin used mat which satisfied with bonding test, waterproof test, resistance to chemical attack test, resistance to impact test and freezing and thawing test is confirmed the basic property.

• Journal of Microbiology
• /
• v.45 no.6
• /
• pp.593-596
• /
• 2007

In this study, we describe the development of a simple and efficient method for cell lysis via the insertion of a bacteriophage lambda lysis gene cluster into the pET22b expression vector in the following order; the T7 promoter, a gene for a target protein intended for production, Sam7 and R. This insertion of R and Sam7 into pET22b exerted no detrimental effects on cellular growth or the production of a target protein. The induction of the T7 promoter did not in itself result in the autolysis of cells in culture but the harvested cells were readily broken by freezing and thawing. We compared the efficiency of the cell lysis technique by freezing and thawing to that observed with sonication, and determined that both methods completely disintegrated the cells and released proteins into the solution. With our modification of pET22b, the lysis of cells became quite simple, efficient, and reliable. This strategy may prove useful for a broad variety of applications, particularly in experiments requiring extensive cell breakage, including library screening and culture condition exploration, in addition to protein purification.

• Journal of Embryo Transfer
• /
• v.7 no.1
• /
• pp.13-19
• /
• 1992

This study were carried out to investigate the effective concentration of cryoprotective agents and sucrose by one-step straw method, and to determine the optimum thawing temperature and equilibration time of frozen porcine embryos. The porcine embryos foflowing dehydration by cryoprotective agents and a various concentration of sucrose were directly plunged into liquid nitrogen and thawed in 3$0^{\circ}C$ water. Survival rate was defined by FDA test. The results are sunnnarized as follows : 1. The survival rates of porcine embryos after ultrarapid frozen4hawing in the freezing medium with a various concentration of glycerol, DMSO and propanediol added 0.25M sucrose were higher survival rate than those of sucrose concentration of 0.50M. 2. The survival rates of porcine embryos after ultrarapid ftozen4hawing in the freezing medium added 0.25M and 0.SOM sucrose were higher survival rate than those of sucrose concentration of 0.75M and 1.00M. 3. The temperature thawed at 2$0^{\circ}C$ and 3$0^{\circ}C$ resulted in a significantly higher embryos survival rate after 72 hrs in culture than did at 35$^{\circ}C$. 4. The equilibration time on the survival rate of porcine embryos was attained after short period of time(2.5~5 min.) in the freezing medium higher than long period of time(10~20 min.).

• Journal of Korean Society of Environmental Engineers
• /
• v.28 no.2
• /
• pp.183-190
• /
• 2006

An experimental study was conducted to evaluate the effect of freezing-thawing and air pollutants on the weathering of $TiO_2$ loaded granite. And the granite was coated with $TiO_2$ catalyst and tested. After freezing-thawing and air pollutants experiments the mineral compositions of the granite surface were lower then that of the fresh granite. Density of the weathered granite was steadily decreased from $2.60g/cm^3\;to\;2.55{\sim}2.56g/cm^3$, but absorption ratio and porosity were slightly increased. From these results, it was expected that granite could be weathered by freezing-thawing md air pollutants. In the case of $TiO_2$ was coated to the granite, the compressive strength and absorption ratio were slightly enhanced compared to the $TiO_2$ non-coated granite. Therefore, the $TiO_2$ coating method tested in this study considered to be a viable method to assist in the conservation of granite from environmental contaminants.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1998.10b
• /
• pp.791-796
• /
• 1998

Air voids existed in hardened concrete have an important influence on concrete deterioration such as carbonation, freezing and thawing, and corrosion of embedded steel in concrete. Therefore it is very significant to investigate the pore structure of system(size, number and continuity of air voids) to solve the reason caused concrete deterioration. The purpose of this study is to develop the standard method of measuring air voids which affect properties in hardened concrete using image analyzing system. This paper presents the settlement of rapid and exact experimental method which extracts fine bubbles, calculates the number of air voids, and determines air-void distribution using image analyzing system with computer.

• Clinical and Experimental Reproductive Medicine
• /
• v.29 no.2
• /
• pp.149-157
• /
• 2002

Objectives: To assess the scavenging effect of carnitine derivatives on oxidative damage to sperm during sperm processing, cryopreservation and thawing. Materials and Methods: Fresh semen samples from 20 normal healthy volunteers were collected by masturbation after at least 48 hours abstinence. After liquefaction of semen samples at room temperature, the specimens were diluted with sperm wash media (Ham's F-10, Life technologics) to a uniform density of $20{\times}10^6/ml$. L-carnitine or acetylcarnitine were added with various concentration of $0{\mu}M$, $10{\mu}M$, $30{\mu}M$ in semen sample or cryoprotectant. All specimens were cryopreservated at $-196^{circ}C$ $LN_2$ for 3 days. Sperm motility, vitality, fertilizing capacity, reactive oxygen species formation and the level of lipid peroxidation were analyzed by computer assisted semen analyzer, eosin-nigrosin stain, hypoosmotic swelling test, chemiluminescence and thiobarbituric acid method, respectively, during sperm processing, cryopreservation and thawing. Results: The sperm motility was only increased in proportion to the concentration of acetylcarnitine with no statistical significance (p>0.05). The sperm vitality was also significantly improved in proportion to the concentration of acetylcarnitine with statistical significance (p<0.05). The sperm fertilizing capacity was significantly increased in proportion to the concentration of L-carnitine and acetylcarnitine and reactive oxygen species generation and lipid peroxidation were significantly decreased with same fashion (p<0.05). On comparison of effects between L-carnitine and acetylcarnitine, acetylcarnitine was superior to L-carnitine on the improvement of sperm motility and vitality as well as the suppression of reactive oxygen species generation and lipid peroxidation. Conclusions: These results suggest that carnitine derivatives have a scavenging effect against oxidative damages during sperm processing, cryopreservation and thawing. Therefore, carnitine derivatives may be useful as an oral antioxidant in patients with male infertility due to increased ROS generation.

• Journal of Embryo Transfer
• /
• v.16 no.2
• /
• pp.133-138
• /
• 2001

The aim of this study was to identify the method on extended canine semen exposed to freezing as assessed by motility, survival and acrosomal changes following different freezing ramp rates. Five ejaculates collected by digital manipulation twice weekly from three dogs (Shih-Tzu) were added Tris-Egg Yolk (TE) buffer and divided into 4 aliquots according to formulation of our laboratory. After cooling to 4$^{\circ}C$ by ramp rate of 0.6$^{\circ}C$/min, the samples frozen by ramp rates of 1.6$^{\circ}C$/min to -$25^{\circ}C$, 3$^{\circ}C$/min to -35$^{\circ}C$, 8.9$^{\circ}C$/min to -7$0^{\circ}C$ and 19$^{\circ}C$/min to -11$0^{\circ}C$, respectively, and then stored in L$N_2$for 2days. Each sample was evaluated on their motility, survivability and acrosome integrity at different thawing temperature. The ramp rate of 3$^{\circ}C$/min to -35$^{\circ}C$/h for freezing and thawing temperature of 37$^{\circ}C$ obtained the highest results to improve survivability, motile spermatozoa and intact acrosome appearance than other onditions. In conclusion, we may suggest freezing semen for canine artificial insemination is more efficient with freezing at a ramp rate of -3$^{\circ}C$/min to -35$^{\circ}C$ and thawing with a water bath adjusted to 37$^{\circ}C$.