This study investigates the behavior of bentonite, used as a buffer material in deep geological disposal systems, in the context of pore morphology under the influence of field-collected groundwater conditions. The bentonite was processed into block form using cold isostatic press (CIP) and subsequently analyzed for its pore morphology in situ using synchrotron X-ray computed tomography (CT) within the field-collected groundwater environment. Bentonite buffers play a critical role in deep geological disposal systems by preventing contact between disposal containers and groundwater. Bentonite typically exhibits swelling upon contact with water, forming few layers of water molecules between its structural layers. However, the presence of ions such as K+ and Cl- can lead to a sharp reduction in swelling pressure. Loss of swelling pressure could negatively impact the integrity of future deep geological disposal systems, making its assessment crucial. This study involves processing various types of bentonite, including natural Na-type bentonite, into block forms and subjecting them to exposure in both deionized water and field-collected groundwater conditions. Internal pore morphology changes were measured using Xray CT technology.

Hydride reorientation is one of the major concerns for cladding integrity during dry storage. In this study, mechanical property of post-reorientation cladding was investigated according to the morphology and amount of the hydrides. Cladding peak temperature limit 400°C was suggested by U.S. NRC in concern of cladding creep and hydride reorientation. In line with this regulatory limit, hydride reorientation was conducted during cool-down process from the maximum temperature of 400°C, using constant internal pressurization method. The specimens were charged for hydrogen from 100 to 1,000 wppm, and various pressures range of 7.5-18.5 MPa were applied. The morphology was examined by optical microscopy. Radial hydride fraction (RHF) and radial hydride continuous path (RHCP) were calculated using image analysis software PROPHET. Finally, strain energy density (SED) was investigated via ring compress tests and the hydrogen concentration was analyzed. The result shows that when RHF is higher than 5%, SED exponentially decreases with RHF. For RHF less than 5%, SED was primarily affected by the total amount of hydrogen. Shortened length of radial hydrides with the presence of circumferential hydrides may block the radial propagation of crack. The result implies that lower burnup spent fuel with lower hydrogen concentration may be more vulnerable in terms of radial hydride compared to higher burnup fuel.

Particle morphology change and different experimental condition analysis during composite fabrication process by traditional ball milling with discrete element method (DEM) simulation were investigated. A simulation of the three dimensional motion of balls in a traditional ball mill for research on the grinding mechanism was carried out by DEM simulation. We studied the motion of the balls, the ball behavior energy and velocity; the forces acting on the balls were calculated using traditional ball milling as simulated by DEM. The effect of the operational variables such as the rotational speed, ball material and size on the flow velocity, collision force and total impact energy were analyzed. The results showed that increased rotation speed with interaction impact energy between balls and balls, balls and pots and walls and balls. The rotation speed increases with an increase of the impact energy. Experiments were conducted to quantify the grinding performance under the same conditions. Furthermore, the results showed that ball motion affects the particle morphology, which changed from irregular type to plate type with increasing rotation speed. The evolution was also found to depend on the impact energy increase of the grinding media. These findings are useful to understand and optimize the particle motion and grinding behavior of traditional ball mills.

이 연구는 진안군의 산림과 마을숲 주변 경관의 서식지 변화 과정을 경관지수와 서식지 형태 분석으로 밝히고, 생물다양성 보전을 위한 경관생태학적 함의를 제시하고자 수행되었다. FRAGSTATS과 GUIDOS 서식지 분석 프로그램에서 1989년과 2006년의 토지피복도를 활용하여 진안군 산림과 34개 대표적인 마을숲 주변 경관의 서식지 구성과 짜임을 분석하였다. 진안군 핵심과 통로 서식지의 면적, 서식지 연결성은 1989년보다 2006년에 낮았다. 또한, 마을숲 주변 서식지의 파편화 정도와 서식지의 구조적, 기능적 연결성은 1989년보다 2006년에 낮았다. 서식지 파편화를 감소시키고 연결성을 향상시키기 위해 기존에 존재하는 마을숲과 주변 생태통로를 보전하면서 새로운 생태통로를 조성해주는 전략이 필요하다. 본 연구의 경관지수와 서식지 형태 분석은 급격하게 변하는 경관에서 서식지 기능과 짜임을 분석하는 데 효과적인 기법으로 활용될 수 있다.

본 연구에서는 경안천 유역을 대상으로 과거의 경년 항공사진과 지형도를 이용하여 하천형태의 변화를 분석하고, 하천주위의 토지이용변화를 비교해 보고자 하였다. 이를 위해 경안천 유역의 지방 1, 2급 하천에 해당하는 1966년, 1981년, 2000년 항공사진에 내, 외부표정을 실시하여 정사영상을 생성하였으며 또한 1914 - 1915년 지형도를 이용하여 1966년, 1981년, 2000년의 하천과 비교하였다. 이 영상을 이용하여 경년 하천형태와 하천부지의

Genetic diversity of 47 East-Asian vegetable soybean was characterized by means of agro-morphological traits and RAPD markers. A field trial was conducted to evaluate 14 agro-morphological traits. To study RAPD-based DNA analysis, a total of sixty 10-mer random primers were screened. Of these, 23 polymorphic markers in 16 varieties used for screening. Among 207 markers amplified, 48 were polymorphic for at least one pairwise comparison within the 47 varieties. A higher differentiation level between varieties was observed by using RAPD markers compared to morphological markers. Correspondence analysis using both types of marker showed that RAPD data could fully discriminate between all varieties, whereas morphological markers could not achieve a complete discrimination. Genetic distances between the varieties were estimated from simple matching coefficients, ranged from 0.0 to 0.640 with an average of 0.295~pm 0.131 for morphological traits and 0.042 to 0.625 with an average of 0.336~pm 0.099 for RAPD data, respectively. Cluster analysis based on genetic dissimilarity of these varieties gave rise to 4 distinct groups. The clustering results based on RAPDs did not match with those based on morphological traits. Geographical distribution of most varieties in each of the groups were not well defined. The results suggested that the level of genetic diversity within this group of East-Asian vegetable soybean varieties was sufficient for a breeding program and can be used to establish genetic relationships among them with unknown or unrelated pedigrees.