• 한국농림기상학회지
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• 제11권4호
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• pp.213-220
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• 2009

복숭아 나무 '장호원황도' 품종의 결과지에 대한 월동기간 중 생리적 내한성을 가리키는 지표로서 일별 기온에 의해 계산되는 휴면심도를 설정하였다. 휴면심도 추정모형의 최적모수(기준온도, 저온요구도)를 도출하기 위해 2008-2009 겨울 동안 총 12회에 걸친 실험을 수행한 결과, 내생휴면해제에 필요한 '장호원황도'의 기준온도 $5.7^{\circ}C$와 저온요구도 -108을 얻었다. 1992-2008년 기간 중 수원기상대 일 최고 및 최저기온자료를 이용하여 이 모형에 의해 '장호원황도'의 만개기를 예측하고 기존의 DVS모형과 회귀모형에 의한 예상 만개기와 비교한 결과 이 모형의 예측능력이 우수하였다. 이 모형에 의해 추정된 휴면심도를 선행연구에서 얻은 동해유발온도와 결합하여 동해위험확률을 계산할 수 있는 경험식을 도출하였다. 날짜와 최저기온이 주어지면 이 식에 의해 '장호원황도'의 갈변이나 발아장해 등 동해증상이 나타날 수 있는 확률, 즉 동해위험 지수를 미리 알 수 있으므로 복숭아 재배농가의 동해 경감에 기여할 것으로 기대된다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.78-89
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• 2008

In this study the frost penetration depth along national roads in Korea were measured and analyzed over several years. The frost penetration depth was analyzed with respect to the Provinces of Korea and sunny/shaded areas. Additionally, the measurement results were compared to the formular of the US Army Corps of Engineers and Terada in Japan.

• 한국수정란이식학회지
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• 제28권3호
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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.

• 한국도로학회논문집
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• 제12권1호
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• pp.47-54
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• 2010

본 연구에서는 콘크리트 포장의 균열, 스폴링 등의 파손문제를 해결하기 위해 국내 시공사례가 없는 이층 포설 공법의 도입 및 기술 경제적 타당성을 검토하고자 하였다. 본 포장공법중 하나인 강섬유 보강 콘크리트(SFRC, Steel Fiber Reinforced Concrete)의 포장 배합 적용성이 검토되었다. 강섬유 함량과 포장 높이가 산정되었으며, 강섬유 보강 콘크리트의 물성 평가를 위해 압축강도, 휨강도, 휨인성 지수, 인장강도, 피로강도를 측정하였다. 슬럼프와 공기량은 대부분이 시방 기준을 만족하였으며, 28일 강도도 교통개방을 할 수준 정도로 발현되었다. 휨강도 실험 결과, 강섬유 보강 콘크리트가 무보강 콘크리트에 비해 휨인성은 증가하였지만 휨강도는 증가하지 않았다. 에너지 흡수능력, 피로 저항성 및 동결 융해저항성은 강섬유 보강 콘크리트가 무보강 콘크리트에 비해 향상되었다. 향후, 시험시공을 통해 강섬유 보강 콘크리트의 현장 적용성 및 공용성을 평가할 것이다.

• 대한토목학회논문집
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• 제8권2호
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• pp.147-154
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• 1988

우리나라의 지반(地盤)은 겨울에는 동결(凍結)하고 온난한 계절에는 융해(融解)하는 계절적(季節的) 동결지반(凍結地盤)이다. 이러한 계절적(季節的) 동결지반(凍結地盤)에서는 동결(凍結)과 융해(融解) 상태의 순환과정을 반복하게 되므로 토목건축구조물(土木建築構造物)을 축조(築造)할 때는 동결(凍結)의 영향을 받는 깊이를 알아 두어야만 한다. 본 논문(論文)에서는 우리나라 전국(全國)의 최대동결심도(最大凍結深度) 분포도(分布圖)가 작성 제시(提示)되며 최대동결심도(最大凍結深度)를 추정할 수 있는 새로운 방법이 모색된다. 본(本) 연구(硏究)의 결과(結果), 최대동결심도(最大凍結深度)는 동결지수(凍結指數)의 평방근과 선형(線形) 관계에 있지 않음이 밝혀졌다. 이러한 동결심도(凍結深度)와 동결지수(凍結指數)의 평방근 상이의 비선형성(非線型性)을 보완하고 보다 현실에 근접한 동결심도(凍結深度) 산정(算定)을 위하여 새로운 경험식(經驗式)이 제안(提案)된다. 이 식에는 동결지수(凍結指數) 이외에 흙의 건조단위중량 및 함수비가 고려되어진다. 또한 이 식은 지금까지 사용되어 오고 있는 기존식(旣存式)과 비교(比較) 검토된다.

• 한국지반환경공학회 논문집
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• 제15권1호
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• pp.35-41
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• 2014

계절적 동토 지역에 건설되는 도로, 철도 등의 구조물은 동결 융해의 반복으로 인한 기후조건으로 인해 동상 피해가 발생한다. 구조물 건설 시 동결깊이는 계절적 동토 지역에 건설되는 도로, 철도의 구조물 설계에 매우 중요한 요소이다. 본 연구에서는 현장시험시공을 통한 고속철도 콘크리트 궤도의 동결깊이 및 동상량 계측을 수행하였다. 강원도, 경기도, 충청북도 철도노선 인근에 모형 콘크리트 궤도를 설치한 후 메틸렌블루를 이용한 동결깊이와 동상량을 측정하였다. 본 연구를 통해 계측된 최대 동결깊이 및 동상량은 국내 한랭지 철도노반설계를 위한 기초자료로 활용될 수 있을 것으로 판단된다.

• Clinical and Experimental Reproductive Medicine
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• 제51권3호
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• pp.213-224
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• 2024

Objective: Some age-related testicular changes, such as Sertoli cell vacuolization and blood-testis barrier breakdown, reduce total sperm production and male fertility. Therefore, this study investigated the effect of vitamin E on restoring testicular function in aged mice. Sperm cryo-resistance was also assessed. Methods: Twenty-eight 48-week-old male Naval Medical Research Institute mice were divided into four groups for a daily gavage of vitamin E: the control group received distilled water, while the three treatment groups were administered 100, 200, and 400 mg/kg, respectively, for 4 weeks. Subsequently, semen analyses, DNA fragmentation index (DFI), and protamine deficiency tests were conducted. Testicular histology, tissue antioxidant enzyme activity, and gene expression levels were also assessed. Results: The two higher dosages of vitamin E were associated with a higher sperm count, greater progressive motility, and improved sperm morphology (p<0.05). These benefits were also evident after sperm freezing (p<0.05). Although chromatin abnormalities increased following vitrification, the treatment groups showed better outcomes (p<0.05). The tubular diameter, epithelium height, and luminal diameters remained unchanged with age. The tissue antioxidant capacity was greater in the groups receiving the high doses of vitamin E. Additionally, significant increases in inhibitor of DNA binding protein-4 (Id4) and GDNF family receptor alpha-1 (Gfra1) expression were observed in the higher vitamin E dosage groups, and promyelocytic leukemia zinc finger protein (Plzf) expression was notably present in the 400 mg/kg treatment group compared to the control group (p<0.05). Conclusion: Antioxidant supplementation might enhance reproductive outcomes in aging males. The observed effects included improved sperm cryo-resistance, which is advantageous for future applications such as sperm freezing or fertility preservation.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2008년도 춘계 학술논문 발표대회
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• pp.57-60
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• 2008

This study investigated the results of insulation heat curing method using double layer bubble sheet in slab concrete and mass concrete in cold weather environment. First of all, when double bubble sheets are applied, it was shown that slab concrete was protected from early freezing by remaining between 6 and 15℃ even in case outside temperature drops -9℃ below zero until the 2nd day from piling, and in the case of mass concrete, with the maximum temperature difference between the center and surface less than 4℃, crack occurrence index was close to 2 and no hydration heat crack occurred by internal constraint. The insulation heat preservation curing method using the double bubble sheet applied in this field prevented early freezing owing to stable curing temperature management, deterring concrete strength development delay at low temperature, and obtained the needed strength. Also, it was proven that the method is highly effective and economic for cold weather concrete quality maintenance through curing cost reduction like construction period shortening and labor cost reduction, etc by reducing the process of temporary equipment installation and disassembling.

• Geomechanics and Engineering
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• 제38권2호
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• pp.205-214
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• 2024

Permafrost refers to the condition where the ground is frozen. It is crucial to review and evaluate the ground's characteristics before construction. In this study, electrical resistivity surveying is chosen as the investigative technique to apply and illustrate the results on the state of permafrost ground and to summarize its applicability. Field experiments are conducted in the Yeoncheon area of South Korea, which has a freezing index of 522.6°C·days. The target area is categorized into two ground conditions: the first where the original ground freezes, and the second involves excavating the original ground up to a depth of 3 meters, backfilling it, and then artificially injecting fluid. Thus, frozen ground conditions are simulated under both natural and artificial circumstances. Electrical resistivity surveys are performed under both above-freezing and sub-zero temperature conditions, with the experiments conducted at sub-zero temperatures revealing relatively more high-resistivity zones due to the temperature conditions. In this area, the distribution of soil moisture content is also investigated using the Time Domain Reflectometry (TDR) technique. It is observed that the ground into which water is artificially injected had a relatively higher moisture content, although the difference is minor. Finally, a 3D map of the target ground is constructed based on the measured electrical resistivity values, and through this, the distribution of porosity, a crucial design parameter, is also depicted. This research demonstrates that the electrical resistivity technique can effectively evaluate the state of frozen and unfrozen ground and further suggests that it can detailed extract the characteristics of the target ground.

• 한국가축번식학회지
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• 제10권1호
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• pp.19-26
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• 1986

This experiment was carried out to investigate the effect of bovine serum ablumin (BSA), sugars, glycerol equilibration time, straw size and thawing method on the survival index and the morphology of frozen boar spermatozoa. The results obtained were summarized as follow: 1. When the semen frozen in BF5 dilutor as pellet form was thawed in BTS at 37$^{\circ}$and 50$^{\circ}C$, BF5 dilutor with fructose showed higher sperm survival index than that with dextrose, however, when the semen was thawed on dry test tube at 37$^{\circ}C$, BF5 dilutor with sucrose showed higher sperm survival index than with other sugars. 2 When the semen forzen in BF5 dilutor with straw and thawed at 37$^{\circ}C$, BF5 dilutor with dextrose showed higher sperm survival index than those with other sugars, and there was no difference in sperm survival index between 0.5 and 1.0 ml straws. 3. The sperm survival index of frozen sperm was significantly (P<0.05) improved due to addition of BSA (0.05%) to BF5 dilutor. 4. When the extended semen with BF5 dilutor contatining 0.01 to 0.05% of BSA was frozen in the straw, the semen without glycerol equilibration showed significantly (P<0.05) higher sperm survival index than those with 2, 4 and 6 hrs glycerol equilibration time. 5. The sperm frozen in BF5 dilutor with dextrose or fructose, sucrose and raffinose showed 77 to 88% in normal acrosome rate and no difference among sugars. 6. The frozen semen showed lower normal acrosome rate than the first and second diluted semen, whereas the frozen semen showed higher swollen, damaged and missing acrosome rate than the first and second diluted semen. 7. Damaged and missing acrosome rate of sperm head due to freezing was somewhat inhibited by addition of BSA (0.01 to 0.05) to the BF5 dilutor.