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2013년 강우 및 홍수사상 분석: 영산강·섬진강 유역
성장현,이준호,원유승,김양수 한국방재학회 2014 한국방재학회 학술발표대회논문집 Vol.2014 No.-
본 연구에서는 2013년 영산강과 섬진강 유역에 발생한 강우 및 홍수사상을 평년 및 예년과 비교하여 분석하였다. 분석결과, 6월, 8월∼9월은 평년대비 50% 수준에 그쳤으나, 7월은 장마전선의 영향으로 4일부터 7일까지 유역평균 250mm 강우를 기록하였다. 8월은 작년과 달리 태풍의 직접적인 영향이 없었으나, 23일과 24일에는 유역평균 140mm의 호우가 집중되었다. 강우에 따른 수위 변화를 알아보면 연중 최고수위가 7월 5일에 발생하였고, 이 때에 선암(황룡강), 나주(영산강), 구례2와 송정지점(섬진강)에 홍수주의보가 발령되기도 하였다. 농업용 저수지(광주, 담양, 장성과 나주) 및 다목적 댐(섬진강, 주암, 탐진)의 11월말 수위를 보면 전반적으로 전년에 비하여 낮은 편이었고, 그 중 광주댐은 전년대비 4.60m, 섬진강댐은 9.15m으로 낮은 편이었다.
저항복비를 갖는 건축구조용 내화강의 강도 특성에 미치는 N 첨가의 영향
성장현,배동수,강창룡,추봉식,주동원,김익수 대한금속재료학회(대한금속학회) 2001 대한금속·재료학회지 Vol.39 No.11
The present study investigated the effect of N addition on the strength characteristics of 0.1%C-1%Mn-0.5%Mo-0.02%Ti fire-resistant steel for construction with low yield ratio. 0.1%C-1%Mn-0.5%Mo-0.02%Ti(A) and 0.1%C-1%Mn-0.5%Mo-0.02%Ti-0.015%N(B) specimens showed bainite phase in matrix of ferrite and pearlite phase, the addition of N suppressed the transformation of pearlite and accelerated transformation to bainite. Yield strength(Y.S) ratio, yield and tensile strength of B specimen was higher value than those of A specimen, but yield ratio(Y.R) value was lower. In the two specimens treated by air cooling or quenching and tempering after rolling, yield strength and Y.S ratio decreased slowly with increasing test temperature, and rapidly decreased at over 600℃. But Y.S ratio at 600℃ was higher than 70%. In case of specimen tempered after quenching, yield and tensile strength were higher than that of air cooling specimen but Y.S ratio was lower. With increasing finish rolling temperature, volume fraction of ferrite and pearlite phase was decreased, and volume fraction of bainite and Y.S ratio was rapidly increased, while Y.R value was unchanged. In two specimens, Y.S ratio was strongly controlled by volume fraction of second phase, but Y.R value and yield strength were affected by other factors than the volume fraction of second phase.
複合 組織鋼의 引張性質에 미치는 組織學的 因子에 관하여
成章鉉,韓元澤 동아대학교 공과대학 부설 한국자원개발연구소 1984 硏究報告 Vol.8 No.1
Morphological factors affecting tensile properties were investigated by metallography, tensile test and particle analysis after manufacturing Austenite Dual Phase steel (ADP steel) and Intercritical Dual Phase steel(IDP steel) by heat treatment of Fe-Mn and Fe-Mn-Cr systems. 1) The formation of austenite was largely affected by initial structures before intercritical annealing, and austenite grew from the pearlite colony in Fe-Mn system but grew discontinuously along the plate of cementite in Fe-Mn-Cr system. 2) As for the effects of Cr on the tensile properties, tensile strength and elongation are low for step quenching, but tensile strength increased and elongation decreased slightly for intercritical annealing. 3) In Fe-Mn-Cr system tensile strength and elongation of IDP steel were excellent than those of ADP steel due to the discontinuous dispersion of fine martensite particles at the same volume fraction.
성장현,류영,성기원 대한토목학회 2022 KSCE Journal of Civil Engineering Vol.26 No.4
This study evaluates the effects of climatic conditions and drought phase on occurrence frequency (OF) of forest fire in South Korea, and suggested a deep learning-based estimator for the occurrence frequency of fire. There was a high correlation between frequency and relative humidity (RH, R = -0.663) and wind speed (WS, R = 0.532). Using these correlations, we proposed a deep learning model that can estimate the OF. Among the three deep learning models (RH-WS-AMOF, RH-AMOF, and WS-AMOF) by combining RH and WS with average monthly OF (AMOF) during 1997 − 2019, the RH-WS-AMOF model showed the best performance. R2 and NSE were 0.838 and 0.828, respectively. The higher temperatures and drought lead to increase the potential for forest fire. Standardized precipitation evapotranspiration index was introduced for exploring the link between meteorological drought and forest fire. We confirmed that SPEI can improve the performance of the DBN based on OF estimator in spring. The framework of this study can provide a predictive model for forest fire OF combined with a weather forecast model.
복합조직강의 열처리경로가 조직학적인자 및 기계적성질에 미치는 영향
성장현 東亞大學校 海洋資源硏究所 1988 硏究論文集 Vol.1 No.1
The effect of changes in heat treatment paths and the addition of alloying elements on the formation of ferrite and austenite in dual phase steel heat treated in the two phase field of both ferrite and austenite were investigated. For this investigation Fe-C-Mn-Cr and Fe-C-Mn-Mo alloys were prepared throughout the experiment. The results obtained from this study are summarized as follows. The growth rate of ferrite obtained during isothermal heat treatment in the range of ferrite plus austenite directly from austenite single phase region decreased with the addition substitutional alloying elements such as Mn, Cr and Mo. This phenomena were remarkable with increasing temperatures of isothermal heat treatment. The carbide particles exsisted in the matrix of ferrite became a source of carbon supply at the austenites which were in the vicinity of grain boundary of ferrite. The easist diffusion path of carbon atom from ferrite matrix to austenite was the dislocations formed near to the ferrite due to the continuous growth of austenite. The volume fraction of martensite for the specimens isothermally heat treated after austenitization was shown to be remarkably different compared to that for the specimens obtained by using intercritical annealing, depending on the addition of Cr and Mo. The substitutional alloying elements involved were considered to become more effective to inhibit the formation of ferrite than to accerate the austenite formation. During intercritical annealing of the steel which has the initial structure of ferrite and carbide, tensile strength increased and yield strength became lowered with the formation of austenite at the grain boundaries of ferrite and simultaneously dissolution of carbide. Yield strength and elongation became minimum and maximum respectively after remarkable dissolution of pearlite and carbides.