http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
김원태,이호인,오규환 대한금속재료학회(대한금속학회) 1992 대한금속·재료학회지 Vol.30 No.11
The effects of melt flow rate and alloy composition on the microstructure of spray formed Al-Fe billets have been studied by using a combination of optical and transmission electron microscopy. Three transient regions in void distribution and solidification microstructure appear throughout the billet thickness : initial transient region dominated by chill effect by cold substrate ; quasi-steady state of microstructure beyond the initial transient region ; and final transient region due to decrease in melt flow rate. Large inter-connected void and fine microstructure developed first near the substrate and changes into different types of void and coarsened microstructure depending on thermal condition on the deposit top surface. In the deposit of Al-Fe alloy, monoclinic Al_(13)Fe₄precipitate is often observed with occasional observation of metastable orthorhombic Al_6Fe precipitate formed during flight.
급속응고된 Al-10wt% Ti 합금의 미세조직과 열안정성에 대한 연구
김원태,오규환,금동화,김혜성,이희춘 대한금속재료학회(대한금속학회) 1992 대한금속·재료학회지 Vol.30 No.10
Al-10wt% Ti alloy was rapidly solidified by N₂gas atomization process, and the resulting alloy powders were consolidated by hot extrusion with an extrusion ratio of 17 : 1. The characteristics of the powders and the microstructures of the powders and extrudates have been examined by using a combination of particle size analyser, X-ray diffractometer, and optical, scanning electron and transmission electron microscopes. At-10wt% Ti powders show a spherical shape with mean particle size of 50㎛, and a microstructure of equiaxed α-Al grain of 2-3㎛ with Al₃Ti particles. Powders smaller than 44㎛ consist of α-Al, Ll₂metastable Al₃Ti and DO_(22) equilibrium Al₃Ti. With increasing th powder size, metastable Al₃Ti particles disappears and equilibrium Al₃Ti particles with a petal like shape become dominant. The metastable and equilibrium Al³,Ti particles show following orientation relationships with the surrounding α-Al matrix :[100]_(Al)//[001]DO_(22)-Al₃Ti and[010]Ll₂-Al₃Ti;[100]_(A1)//[100]Ll₂-Al₃Ti and[010]_(Al)//[010]Ll₂-Al₃Ti Extrudates show a uniform show a uniform distribution of equilibrium Al₃Ti particles in α-Al matrix with grain size of 2㎛
홍성호,김우식,김형식,방인완,오규환 한국산업안전학회 1998 한국안전학회지 Vol.13 No.2
This study was initiated to examine the stress and deformation characteristics of the pipelines which were subjected to various environmental conditions in order to confirm their integrity. As the part of them, this paper presents the analysis results for the effect of ground subsidence combined with main loads on buried natural gas pipelines. The ground subsidence which can occur for buried gas pipeline has been classified to the three cases. Finite element method was used to analyze the effect of ground subsidences on pipeline of 26 inch(0.660 m) and 30 inch(0.762 m) diameter used as high pressure (70㎏_f/㎠(6.86 ㎫)) main pipelines of KOGAS. This paper shows the result of stress analysis for the pipelines subjected to those three case ground subsidence. Comparing these results with safety criterion of KOGAS(0.9 σ_y), maximum allowable settlement and loads have been calculated.