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포스터 전시회 : 배관 재질 손상에 미치는 액적충돌침식의 영향에 대한 연구
김경훈 ( Kyung Hoon Kim ),최덕현 ( Duk Hyun Choi ),조연수 ( Yun Su Cho ) 한국액체미립화학회 2012 한국액체미립화학회 학술강연회 논문집 Vol.2012 No.-
Wall thinning erosion in carbon steel piping classified FAC, C/E, LDIE mainly. FAC(Flow Acceleration Corrosion) was investigated by many labs. And, Effect of C/E(Cavitation Effect) is decreased due to design supplementation. LDIE(Liquid Droplet Impingement Erosion) is investigated in aviation industry mainly. On the other hand, LDIE is not studied in NPP(Nuclear Power Plant) industry. Therefore, this research focuses relation between erosion rate and air-water ratio, material. Experiment is conducted in 3 cases of air-water ratio(0.79, 1.00, 1.72) and 3 cases of material(A106B, SS400, A6061). LDIE threshold value and erosion rates are obtained through continuous experiment. NPP`s LDIE prediction theory and management technique were drawn from the obtained data
고체입자 충돌침식으로 인한 배관 재질의 손상에 관한 연구
김경훈 ( Kyung Hoon Kim ),최덕현 ( Duk Hyun Choi ),김형준 ( Hyung Joon Kim ) 한국부식방식학회(구 한국부식학회) 2014 Corrosion Science and Technology Vol.13 No.4
Wall thinning can be classified into three types: flow-accelerated corrosion, cavitation erosion and solid particle erosion. This article presents a study of solid particle erosion, which frequently causes damages to power plants`` pipe system. Unlike previous studies, this study uses a mechanism to make solid particles in a fluid flow collide with pipe materials in underwater condition. Experiment is conducted in three cases of velocity according to solid-water ratio using the three types of the materials of A I06B, SS400, and A6061. The experiments were performed for 30 days, and the surface morphology and hardness of the materials were examined for every 7 days. Based on the velocity change of the solid particles in a fluid flow, the surface changes, the change in the amount of erosion, the erosion rate and the variation in the hardness of carbon steel and aluminum family pipe materials can all be determined. In addition, factor-based erosion rates are verified and a wall-thinning relation function is suggested for the pipe materials.
급성 Vitamin A 중독으로 인한 간세포의 미세형태학적 변화에 대한 연구
최덕현,방희연,서인수,조태환 慶北大學校 醫科大學 1985 慶北醫大誌 Vol.26 No.1
Vit.A 중독의 간상해 기전을 알아보기 위해 체중 20gm 내외의 생쥐에 vit.A 5,000IU 씩을 매일 근육내에 5일간 주사한 후 간에 야기된 변화를 광학 및 전자현미경으로 검색하였던 바 다음과 같은 소견을 얻을 수 있었다. 광학현미경학적으로는 동양혈관 주변에서 Ito세포의 증식을 볼 수 있었다. 간세포는 별다른 변화를 볼 수 없었으며, Kupffer세포가 두드러져 보였다. 전자현미경적으로 간세포는 SER의 증식, RER의 층상구조의 파괴, 불규칙한 모양을 한 mitochondria의 출현 및 cristae 배열의 불규칙화, 그리고 myelin figure의 출현 등을 볼 수 있었다. Ito세포는 증식하였으며, 이들 세포는 지방적으로 충만되어 있고 어떤 세포는 세포체가 파괴된 것도 보였다. Kupper세포는 지방적을 포함하여 괴사된 Ito세포를 탐식하고 있었다. 동양혈관강 및 Disse강은 국소적으로 이들 괴사세포체, 지방적, 비후된 Kupffer세포 및 증식한 Ito세포로 폐쇄되어 있었으며, 이렇게 양강이 폐쇄된 지역에서 간세포의 변성성 변화가 더 심한 편이었였다. 이상의 성적으로 보아 과량의 vit.A에 의한 간손상은 일차적으로 동양혈관 및 Disse강의 폐쇄때문에 야기된 산소결핍 때문이며, 이들 강의 폐쇄는 증식한 Ito세포 및 이들의 파괴 때문인 것으로 사료된다. 파괴된 세포체를 탐식함으로써 비후된 Kupffer세포 역시 이들 강의 폐쇄에 일익을 담당할 것으로 사료된다. 이와 같이 간세포 손상이 산소결핍에 의한 이차적인 것이라고 해석되지만 myelin figure형성은 vit.A 자체의 직접 작용인 것도 배제할 수 없다. The authors studied the ultrastructural changes of the liver after intramuscular injections of large doses of vitamin A to investigate the mechanism of the hepatotoxicity of hypervitaminosis A. Mice were daily injected by 5,000 IU of vitamin A for 5 days. The results obtained were summarized as follow: Light microscopically, proliferation of Ito cells was noted on the perisinusoidal spaces. Liver cells were intact, but Kupffer cells were more prominent. Electron microscopically, the livers cells showed proliferation of smooth-surfaced endoplasmic reticulum, destruction of lamellar structure of rough-surfaced ER, appearance of irregular shaped mitochondria with irregularity in arrangement of cristae and appearance of myelin figures. Proliferated Ito cells showed increased number of fat droplets with destruction of the cell bodies in certain areas. Kupffer cells phagocytized necrotic Ito cells including their fat droplets. Sinusoidal lumina and Disse spaces were partially obstructed by these necrotic cell debris, fat droplets, enlarged Kupffer cells and proliferated Ito cells, in which areas degenerative changes of the liver cells were more prominent. It is suggested that primary hepatotoxicity of the large amounts of vitamin A is exerted by anoxia resulted from obliteration of the sinusoidal lumina and Disse spaces, due to proliferating Ito cells with destruction of them. Enlargement of Kupffer cells due to phagocytosis of the destructed Ito cells also participates in obliteration of sinusoidal lumina and Disse spaces. Although liver cell changes are secondary due to anoxia, myelin figure formation within the liver cells seems to be direct effects of vitamin A itself.