백서 두개골 결손부에서 Biphasic Calcium Phosphate 제작방법에 따른 골 형성 효과 비교

Dept. of Dental Science/석사The purpose of this study is to compare and evaluate the bone regeneration effect and histological result of BCP(biphasic calcium phosphate) with varying methods of material preparation in rabbit calvarial defect. Ten adult male New Zealand rabbits were used in the experiment. Four defects with diameter of 8mm each were formed at the rabbit calvaria and BCPs manufactured with each different material preparation methods were applied in three defects.A BCP used in the first coating group was prepared by coating beta-tricalcium phosphate on HA scaffold surface manufactured with Replica method. The second BCP used in the sacrificial group was prepared by manufacturing biphasic scaffold with sacrificial template method and the third BCP in the foaming group by manufacturing biphasic scaffold with direct foaming method.Four defects were classified as the followings. Group 1(control): bone grafts not applied, Group2 (Coating group): BCP preparation method was replica method and the ratio of hydroxyapatite/beta-tricalcium phosphate (HA/β-TCP) was 7:3. Group3 (Sacrificial group): BCP preparation method was Sacrificial template method and the ratio of HA/β-TCP was 3:7. Group4 (Foaming group): BCP preparation method was direct foaming method and the ratio of HA/β-TCP was 2:8. The animals used in the experiment were sacrificed at 2 week(N=5) and 8 week(N=5).In the histological and histometric measurement results, BCPs used in the three groups showed high space maintenance ability and stability of particles. Compared to the coating group, the sacrificial group and foaming group showed significantly high bone graft resorption rate and especially in the foaming group the largest bone graft resorption rate was shown at 2 and 8 week period and bone regeneration was very even. However, no significant statistical difference in resorption rate and bone regeneration between sacrificial and foaming groups was shown.ope

토류구조물 설계시 지반 물성치 산정에 관한 연구

학위논문(석사)--서울大學校 大學院 :土木工學科,1995.Maste

End Bearing Behavior of Drilled Shafts in Rock

The end bearing behavior of piles socketed in weathered/soft rock is generally dependent upon the mass conditions of rock with fractures rather than the strength of intact rock. However, there are available data and little guidance in the prediction of the end bearing capacity of drilled shafts socketed in weathered/soft rock, considering rock mass weathering. Therefore, a database of 13 load tests was constructed first, and new empirical relationships between the base reaction modulus of piles in rock and rock mass properties were developed. No correlation was found between the compressive strengths of intact rock and the base reaction modulus of weathered/soft rock. The ground investigation data regarding the rock mass conditions(e,g, Em Eur, RMR, RQD) was found to be highly correlated with the base reaction modulus, showing the coefficients of correlation greather than 0.7 in most cases. Additinally, the applicability of existing methods for the end bearing capacity of pile in rock was verified by comparison with the field test data

Analysis of the Role of ESS for Expanding the Renewable Energy Supply : From Energy and Environmental Perspectives

기후변화대응 및 미세먼지 등의 환경문제 해결을 위하여 재생에너지 보급 비중 확대가 필요하다는 공감대가형성되고 있으나, 태양광과 풍력의 높은 출력 변동성으로 인한 전력시스템 안정성 저하에 대한 우려 역시 증대되고 있다. 이에 따라 변동성 대응을 위한 기술적 수단으로서 ESS(Energy Storage System)가 주목받고 있으나, ESS 도입에 따른 구체적인 효과에 대한 정량적인 분석은 부족하다. 따라서 본 분석은 대표적 상향식 분석모형인 TIMES 모형을 이용하여 재생에너지 보급 시나리오 별 ESS의 에너지· 환경 측면 파급효과를 정량적으로 분석하였다. 그 결과 ESS는 재생에너지 보급 확대 뿐만 아니라 전력시스템의 효율향상에 크게 기여할 수 있는 기술로서, ESS 도입을 통하여 높은 수준의 재생에너지 비중에서 발생할 수 있는 초과전력 생산(출력 제한량)을효과적으로 억제할 수 있을 것으로 분석되었다. 또한 ESS는 석탄화력 발전소의 가동율에 대한 적절한 규제가동반되는 경우 온실가스 감축에도 크게 기여할 수 있을 것으로 분석되었다.22Nkc