In this study, corrosion fatigue crack propagation was investigated in pH buffer environment using the giga strength steel and its heat-affected zone, and the results were compared with theoretical model prediction. Also, the pure corrosion effect on fatigue crack propagation in a corrosive environment was compared with the modified Forman equation. As results, the average value of corrosion rate obtained as the ratio of the net corrosion-induced crack length to the total crack length under cyclic loading in the base metal and heat-affected zone under experimental loading conditions. These results exhibit a new theoretical method for corrosion fatigue crack propagation that predicts a purely corrosion effect on the behavior to be determined.
This study was conducted to survey the habitat environment as draft data for restoration and massive propagation method of Forsythia saxatilis were classified as rare species and disappear in Seoul. The light, soil environment in habitat was surveyed and the cutting experiment as species, cutting periods, and rooting promoter was conducted to know physiological characteristic of Forsythia saxatilis The results, light was low to forest tree and soil in the native site indicated that pH 4.78~5.05, EC 0.04~0.05 dS․m-1, OM 1.23~3.27%, Ca 4.21 mg․kg-1, K 0.41mg․kg-1, Mg 0.69 mg․kg-1. 0.01 % N, 0.44mg․kg-1 P showed low and 12.87~23.56cmol+․kg-1 CEC. It was very poor soil environment to live plant as general forest soil. In Propagation, Rooting rate showed hardwood 90% and softwood 100% in summer and softwood 90% in summer and 79% in spring. Rooting rate was showed of each species, Forsythia viridissima 100%, Forsythia ovata Nakai. 80%, tetraploid 60%, and Forsythia saxatilis 90%. There is no effect of rooting promoter treatment. We gained 120 plants by cutting propagation and renaturated to habitat. It is the reason that Forsythia saxatilis disappear at habitat by have no seed and low adaptation of environmental change. To massive propagation by cutting, it is important to control cutting periods rather than rooting promoter treatment.
디지털 TV 방송은 기존 아날로그 방송에 비해 해상도나 음질 등이 매우 뛰어나고 홈쇼핑, 홈뱅킹, 인터넷 검색, 재택근무 및 VOD(video on demand) 등의 멀티미디어 기능을 제공할 수 있는 등 많은 장전을 가지고 있다. 따라서 본 논문에서는 디지털 TV 서비스 전에 본질적인 지역적 전파환경의 분석이 필요하며, ETRI 모델을 적용하여 부산지역에 대한 전파모델을 적용하여 그 제한성을 분석하고자 한다. 따라서 본 논문에서는 디지털 TV 신호가 고품질을 유지할 수 있도록 하기 위하여 산악지역과 고층빌딩이 많은 부산지역의 전계강도를 측정하였다. 본 논문에서는 TV 전파모델을 기준으로 전반적으로 기준모델에 대한 시뮬레이션 결과보다. 낮은 결과를 갖지만 분포 패턴은 비슷하게 나타남을 알 수 있었다. 이론치와 실측치를 비교한 결과 평탄한 지형에 대해서는 비슷한 결과를 가지지만 도심 밀집지역 및 산악 지형에 대해서는 상당한 차이를 가지는 것으로 나타났다. 따라서 ETRI 전파모델 및 자유공간에 대한 전파전파의 이론적 모델링이 부산 지역에 대해서는 적합하지 않는 것으로 판단되었다.