In this study, the differences of holding power according to the shape and weight distribution of concrete weight used in shellfish shell fishery were investigated through the experiments. To investigate the differences in shape, five bar-shaped concrete weights with the same length and different cross-sectional shapes were produced. The sectional shape of each weight was square, triangle, circle, small cross, and large cross (SQ, TR, CI, CR-S, CR-L). Ten rectangular parallelepiped weights with different bottom area and cross-sectional area were produced. To investigate the differences by the weight distribution, the holding power on the square model (SQ) with six 50 g weights at different positions was investigated. All the holding power was obtained by measuring the tensile force generated when the concrete weight was pulled at a constant speed on the sand. As a result, there were no differences in holding power between the ten rectangular weights. However, the experiment on weights with different cross-sectional shapes showed differences in holding power. The holding power was higher in the order of CR-L > CR-S > CI > TR > SQ. In the weight distribution test, the holding power was higher as the front side of the weight was heavier. Generally, the frictional force is the same even if the shape is different, when two objects have the same value in the weight and the roughness. On the other hand, it seems to have a large impact when the shape of the bottom is deformed in the course of pulling the object. Particularly, the larger the degree of protrusion like cruciform weights, the more the holding power increased while deeply digging the bottom. It is also likely that the holding power increases as the front weight increases.

벼의 내한성에 관여하는 생태 및 형태적인 특성을 찾기 위하여 수도과 능도 각 5품종씩을 가지고 파종상자에서 벼를 재배하고 건조처리한 후 다시 관수하여 위주상태에서 생육이 회복되는 정도를 비교하였으며 관련되는 식물체부위의 특성과의 관계를 구한 결과 다음과 같이 요약할 수 있였다. 1. 건조처리후 재생력은 수도가 육도보다 강하였고 수도에서는 인도형품종이 일본형 품종보다 강하였다. 2. 생육단암별 재생력은 생육초기에 가장 높았고 생육이 진전되면서 점점 낮아졌는데 어느 시기에서나 수도가 육종보다 높은 재생력을 나타내었다. 3. 초장과 엽면적의 차이는 건조처리후 재생력에 영향을 미치지 않았다. 4. 뿌리 발달의 특성에 주근의 두께와 뿌리의 총건물중은 수도보다 육도에서 높았으며 이것은 밭재배에서의 수량과 높은 정의 상관이 있었다.