PURPOSES: The objectives of this study are to analyze the current status of pothole during a rainy season and to suggest a future pavement maintenance method via pothole analysis. METHODS: Potholes are caused by moisture submerged in pavement. The pore pressure caused by traffic and environmental loads causes failure between the aggregate and asphalt binder. Thus, heavy rain is a primary pothole creator, especially in aged pavement. To prevent accidents on roadways, Gyeonggi-do has initiated a fast pothole repair program. However, the number of potholes increase every year. In this study, the current status of potholes and maintenance methods are analyzed. Based on these results, a future pavement maintenance method is suggested. RESULTS AND CONCLUSIONS : Gyeonggi-do’s pothole situation is worse than Seoul’s. Problems were founded, as follows. The amount of potholes was large, and the number increased annually. Pothole management is done at a basic level, because there is no long-term plan. Potholes occur frequently at the same site because of the poor quality of emergency repair. Finally, there is no systematic and comprehensive pavement management. Thus, pothole prevention measures are ill-prepared. Therefore, to reduce potholes and to manage high quality pavement, it is necessary to make a long-term pavement management plan.

This study was performed to confirm the microtubule assemblies and methylation patterns of porcine IVF and parthenogenetic embryos. Cumulus-oocyte complexes were collected and matured in vitro for 42 hr. Oocytes were fertilized by prepared fresh sperm or activated parthenogenetically by exposure to electric stimulation and 6-dimethylaminopurine. Porcine IVF and parthenogenetic embryos were cultured in vitro for 6 days. Embryos were stained by immunofluorescence staining method to observe the dynamic of nucleus and microtubules in the first mitotic phase and the methylation patterns in different developmental stages. After then, samples were confirmed and analyzed through a laser-scanning confocal microscope. IVF embryos had a centrosome originated from sperms, which was shown a ɤ-tubulin spot. However, ɤ-tubulin spot was not observed in parthenogenetic embryos. A lower methylation level was observed in IVF embryos compared to parthenogenetic ones at the morula and blastocyst stages. In conclusion, it is considered that microtubule assemblies and genetic regulation mechanism differ between parthenogenetic and IVF embryos.

기존의 RC 교각에 대한 내진성능 연구는 실험여건상 일방향 반복하중을 받는 단주교각에 집중되어 있었다. 그러나 고속도로상의 교각은 대다수가 다주교각으로 이루어져 있으므로, 본 연구에서는 국내고속도로에서 많이 사용되고 있는 2주형 교각에 대한 이축지진하중에서의 지진응답을 실험적으로 조사하였다. 실험체는 지름 400mm, 높이 2,000mm인 2주형 원형 교각 4기를 제작하였으며, 0.1f_{ck}A_g크기의 축방향 하중작용하에서 횡방향 하중을 이축으로 교번반복 재하하였다. 실험변수는 횡구속 철근비와 주철근 겹침이음으로서 기존 단주에 대한 연구결과와 유사하게 이들 실험변수들은 교각의 내진성능에 상당한 영향을 미치고 있었다. 또한 동일하게 설계된 일축하중을 받는 단주와 이축하중을 받는 다주의 내진성능을 비교한 결과 단주의 경우 손상이 하부 소성힌지 한 곳에 집중된 반면 다주의 경우 교축직각방향 하중으로 인하여 손상이 상ㆍ하부 두 곳으로 분산되어 나타났다.