• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.39-45
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• 2017

In this study, permeable repair materials mainly composed of silicate - based inorganic materials(SIM), which are easily available domestically, were prepared as a basic study for the development of permeable repair materials using SIM. SIM were compared and examined for their performance as repair materials by selecting a product group which has many cases of use in foreign countries. The SIM used were mainly composed of sodium, potassium and lithium silicate. Performance evaluation of SIM was performed by absorption and penetration, compression and adhesion, rapid chloride ion penetration, rapid freezing and thawing, and chemical resistance test. According to the test results, SIM showed effective performance in all areas, mainly because SIM permeates into the interior of the capillary and has a dense internal microstructure. Therefore, it can be used variously to improve the durability of concrete based on the results of this experiment.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.4C
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• pp.139-147
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• 2012

In this study, various laboratory tests using bottom ash, which has similar engineering properties with sand, were conducted in order to solve the problem of clogging in granular compaction pile and to address sand supply and demand. In particular, testing was performed to help reduce clogging and minimize voids in a crushed stone compaction pile constructed in soft ground. Based on compaction tests and large diameter direct shear tests, an optimum mixing ratio was determined to be 80:20 (crushed stone to bottom ash) because an 80:20 mixing ratio showed the highest shear strength. Test results showed that as the bottom ash content increased above 20%, internal friction angle decreased. Another test method showed freezing and thawing had little effect when the replacement ratio was over 40%. Therefore, bottom ash mixed compaction piles in soft ground are most economical at a 40% replacement ratio.

• International Journal of Highway Engineering
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• v.12 no.4
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• pp.87-92
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• 2010

This study evaluates the laboratory properties of asphalt binder and mixture modified with R-EPDM(Recycling Ethylene Propylene Dien Monometer), which consists of R-EPDM as a main ingredient that is an industrial by-product made by manufacturing waste EPDM below 50 mesh as an additive. Superpave system was used to determine the PG(Performane Grade) and evaluate the property of R-EPDM modified binder. OACs(Optimum Asphalt Contents) of R-EPDM modified asphalt mixtures were determined by Superpave mix design using gyratory compactor and wheel tracking test and moisture susceptibility test were carried out with R-EPDM modified asphalt mixtures at OACs. The results from these tests, rutting-resistance and freezing and thawing resistance by moisture susceptibility of R-EPDM modified asphalt mixtures were superior to one of general asphalt mixtures(AP-5).

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.633-636
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• 2008

Concrete structures are occur many various deteriorations in the course of time and many efforts have progressed to improve on performance of concrete. The purpose of this study is to evaluate the durability of latex modified mortar in order to repair concrete structure which are happened deterioration. In this study, we tested plastic shrinkage, drying shirnkage, repeated freezing and thawing, permeability and resistance of chemical solution. Latex modified mortar and two kinds of sprayed polymer mortar used on durability test. As a result of test, latex modified repair mortar was exhibited durablilty improvement compared to the conventional sprayed polymer mortars. It is judged the fact that latex modified mortar have no problem in site application but additionally many research will be necessary.

• Journal of Embryo Transfer
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• v.32 no.3
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• pp.235-241
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• 2017

To preserve genetic materials, cryopreservation of the semen from live animals is the main technique to establish cryo-banking system which could be used for artificial insemination and embryo transfer. However, the population of Korean black goat (KBG) becomes to dwindle in number and is now faced genetic erosion by crossbreeding with non-native breeds in small KBG farms. In this study, simple freezing method was used to preserve frozen semen from KBG using spermatozoa of cauda epididymis (CE) and electro-stimulated semen (ES). The negative effects of seminal plasma on fresh sperm was confirmed using precipitation test of Triladyl egg yolk diluent and sperm viability after thawing was compared between CE and ES spermatozoa. When seminal plasma of fresh ES semen was washed with semen washing media (SWM), the rates of live sperm shown no significant difference between CE and ES spermatozoa before freezing. However, the survival rate of frozen/thawed CE sperm was higher than ES ($74.6{\pm}10.6%$ vs $53.8{\pm}5.2%$) with significant difference (p < 0.05). The results of longevity test on frozen/thawed sperm from CE showed healthier sperm than ES. Therefore, spermatozoa from CE could be used for cryo-banking system in KBG lines. The more studies are needed to increase survival rate of ES semen.

• Korean Journal of Animal Reproduction
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• v.25 no.4
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• pp.409-419
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• 2001

This study was to examine whether the in vitro friability, motility and intact acrosome of frozen-thawed bovine and human sperm can be improved by adding Pentoxifylline (PF) or Fertilization Promoting Peptide (FPP). Human semen was frozen ultra-rapidly using Test yolk-buffer (TYB) freezing medium. Additive (PF, FPP) effects in frozen-thawed bovine and human sperm were analyzed by microscopic count for sperm motility and coomassie brilliant blue staining method f3r sperm acrosome intact. The in vitro motility of frozen-thawed bovine sperm with 5 mM PF treatment group (50.0%) was significantly higher than that of control (34.0%) (P＜0.05). In the frozen-thawed bovine sperm was examined, the intact acrosome rate of 50 nM FPP treatment (49.0%) was significantly higher than those of control (30.0%) and 25 nM FPP (38.0%) treatment groups (P＜0.01). In human semen, when in vitro motility of sperm with PF addition prior to freezing was examined, the result of 5 mM treatment group (51.0%) was significantly higher than those of control and 2.5 mM treatment group (39.0, 40.0%) (P＜0.01). In addition, 50 nM (75.5%) FPP adding in all treatment procedures for human semen freezing (before freezing, freezing and after thawing) was significant effect on maintenance of the sperm intact acrosome percentage (control: 45.0; 25 nM: 53.0; 100 nM: 68.0%) (P＜0.01). Also, the intact acrosome rate of human sperm with FPP (65.0%) was significantly higher than that with PF (43.0%) (P＜0.05), although sperm motility was slightly higher in PF treatment group. These results suggest that improved sperm motility and intact acrosome of frozen thawed bovine and human sperm can be obtained by addition of PF or FPP, and that the enhanced in vitro viability, motility and intact acrosome can be obtained by addition of FPP in all semen freezing procedures.

• Korean Journal of Animal Reproduction
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• v.23 no.2
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• pp.141-148
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• 1999

This study was to test whether the viability of bovine hatched blastocysts (HBs) can be maintained after vitrification and thawing. The HBs were produced in vitro at Day 9 and Day 10 after IVF, and they were classified to small (S-HBs; ø$\leq$300 ${\mu}{\textrm}{m}$) and large(L-HBs; ø＞300 ${\mu}{\textrm}{m}$) on the basis of embryo diameter using eyepiece micrometer. As freezing solution, we used EFS35 which consisted of 35% ethylene glycol (EG), 18% ficoll, 0.3 M sucrose and 10% FBS added in mDPBS. Vitrification was taken by two-step method, the HBs were equilibrated in 10% EG for 5 minutes and then shortly exposed in EFS35 and plunged into L$N_2$for 30~45 sec. After thawing, the survival rates were assessed by the re-expansion of the blastocoel during 2 h and 16 h of culture. The results obtained in these experiments were summarized as follows; 1) When the blastocysts(40.8%) recovered at Day 8 after IVF were further cultured for 24 h(Day 9 after IVF) and 48 h(Day 10 after IVF), the rates of HBs were 20.5% and 6.7%, respectively. Also, the total cell number of HBs on Day 9 was significantly higher than that of HBs on Day 10 (p＜0.01). 2) When the effects of freezing solution to the survival of Day 9 L-HBs were examined, the rate of vitrified group (75.7%) was significantly lower than 100% of control and exposed group(p＜0.05). 3) When the survival rates of vitrified HBs according to size and developmental age were examined, the data of L-HBs (75.5%) and S-HBs(63.6%) on Day 9 were slightly higher than those of L-HBs(64.3%) and S-HBs(60.7%) on Day 10. 4) Also, when the in vitro survival of Day 9 HBs was evaluated under different culture condition after thawing, the result in culture medium only (79.3%) was significantly higher than 43.2% in co-culture group (p＜0.05). These results demonstrated that bovine HBs can be successfully cryopreserved by two-step vitrification method using EFS35.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.5
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• pp.128-135
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• 2010

Polymer-modified cement mortar(PCM) has been widely used for strengthening of the concrete structures due to its excellent physical properties such as high strength and durability. Adhesive strength or behavior, on the other hands, between PCM and concrete is very important in strengthening the concrete member using PCM. Therefore the adhesive failure mechanism between PCM and concrete should be fully verified and understood. This study was performed to evaluate adhesive strength of PCM to the concrete by the direct pull-out test. In the direct pull-out tests, the adhesive strength under the various pre-treatment conditions such as immersion, thunder shower, freezing and thawing are evaluated. Also, the field direct pull-out test are performed to investigate the adhesive strength of mock-up test specimens. In the results of the test, the adhesive strength value by field test are lower than those of the standard curing condition. From these comparison and investigation, field test result was similar with the thunder shower test result. The results of the test was used to evaluate the korean industrial standard of polymer modified cement mortars for maintenance in concrete.

• Clinical and Experimental Reproductive Medicine
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• v.19 no.2
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• pp.153-162
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• 1992

To solve the logistical problems of the sperm penetration assay (SPA) to provide just a sufficient number of hamster ova exactly when they are needed, a new method to cryopreserve the ova has been devised (1-step dehydration and 2-step thawing). After freezing & thawing of zona-intact (ZI) and zona-free (ZF) hamster ova according to this new method, the frozen-thawed ova were compared with fresh, control ova (FO) in terms of the degree of sperm penetration in SPA using semen samples from fertile donors, subfertile, and infertile male. Each sperm sample was capacitated for 42 hours inTEST-Yolk Buffer before insemination in SPA. In fertile doner, both the penetration rate and penetration index were lower in SPA using frozen ova (ZI; 92.4%, 6.2, ZF; 63.7%, 3.9) than those of SPA using fresh ova (99.3%, 8.4). There was a significant correlation between the penetration index of SPA using FO and ZI (p<0.001), and between those of SPA using FO and ZF and ova (p<0.001). In subfertile patient, both the penetration rate and penetration index were lowered in frozen ova (ZI; 62.3%, 1.3, ZF; 21.8%, 0.4) than those of fresh ova (74.8%, 1.8). There were significant correlation between the penetration rate and penetration index in ZI ova (p<0.05 and p<0.001, respectively). In infertile patient, both the penetration rate and penetration index were ZI; 3.1%, 0.0, ZF;0.0%, 0.0, respectively. There were significant correlation between the penetration rate and penetration index in ZI ova (p<0.05).

• Korean Journal of Animal Reproduction
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• v.13 no.2
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• pp.113-120
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• 1989

In order to determine the sex of preimplantation embryos prior to transfer in cattle, a series of experiments were carried out using 45 Holstein donor cows to examine the ovarian response on the gonadotropin and PGF2${\alpha}$, and the morphology of fresh embryos or frozen/thawed embryos after deep freezing at -196$^{\circ}C$. The sexing of embryos treated with the medium containing H-Y antiserum(10%, v/v) and FITC anti-mouse IgG(10%, v/v) were analysed by chromosomal analysis, and the sex of the embryos which survived were ascertain after delivering the pups. The results obtained were summarized as follows ; 1. The average number of developed follicle and corpus luteum per cow were 13.5 and 8.1, and the ovalation rate was 60.1%. 2. Of 220-ova recovered, 75(34.1%) were morula and 91(41.4%) were blastocyst, and the morphological normal and abnormal rate of ova recovered were 75.5% and 24.5%, respectively. 3. Of 39 frozen/thawed embryos, the scores of normal morula and blastocyst, after thawing were 79.2%(19/24) and 73.3%(11/15). The average rate of frozen/thawed embryos which appeared morphologically normal post thawing was 76.9%(30/39). 4. The sex ratio was measured using the embryos treated with immunofluorescence assay to examine the relationship between embryo developmental stage, sex ratio of morula stage embryo was 42.2%(19/45) fluorescing and 57.8%(26/45) non-fluorescing, on the other hand, the ratio switched to 46.8%(29/62) fluorescing and 53.2%(33/62) non-fluorescing embryo in blastocyst stage. The sex ratio was also measured between fresh and frozen/thawed embryos, fresh and frozen/thawed treated embryos were indicated 45.8%(38/83) fluorescing, 54.2%(45/83) non-fluorescing and 41.7%(10/24) fluorescing, 58.3%(14/24) non-fluorescing. This trend indicated the approximal sex ratio was 1 : 1. 5. The result of karyotype test showed the successful rate of sexing embryo is fluorescing and non-fluorescing was 21.2%(7/33) and 29.6%(8/27). The female to male ratio within 33 fluorescing was 28.6 : 71.4, and the ratio of 27 non-fluorescing embryos was 87.7 : 12.5. 6. Of the embryo transferred after assignment of H-Y phenotype, five of the fluorescing embryos survived to term, all was males. Whereas six non-fluorescing embryos also survived to term and the sexes of the calves were 1 male 5 female.