• Journal of Advanced Marine Engineering and Technology
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• 제39권8호
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• pp.828-832
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• 2015

This study is conducted for the evaluation of corrosion and lifetime prediction of fire extinguishing pipelines in residential buildings. The fire extinguishing pipeline is made of carbon steel. Twenty-four samples were selected among all the fire extinguishing pipelines in a building; the selection was based on specimenspositions, pipeline diameters, and pipeline thickness. Analysis was conducted by using the results of visual inspection, electrochemical potentiodynamic anodic polarization test, pitting depth measurements, and extreme value statistics with the Gumbel distribution. The maximum pitting depth and remaining life were statistically predicted using extreme value statistics. During visual inspection, pitting corrosion was observed in several samples. In addition, extreme value statistics demonstrated that there were several pipelines that were very sensitive to pitting corrosion. However, the pitting corrosion was not critical in all the pipelines; thus, it was necessary to change only those pipelines that were severely corroded.

• 한국수자원학회논문집
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• 제33권S1호
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• pp.20-27
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• 2000

The grid-based KIneMatic wave STOrm Runoff Model(Kim, 1998; Kim, et al., 1998) which predicts temporal variation and spatial distribution of saturated overland flow, subsurface flow and stream flow was evaluated at two watersheds. this model adopts the single overland flowpath algorithm and simulates surface and/or subsurface water depth at each cell by using water balance of hydrologic components. the model programmed by C-language uses ASCII-formatted map data supported by the irregular gridded map of the GRASS (Geographic Resources Analysis Support System) GIS and generates the spatial distribution maps of discharge, flow depth and soil moisture of the watershed.

• 물과 미래
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• 제5권2호
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• pp.30-43
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• 1972

The paper describes on the hydrologic analysis of point rainfall data of the three major areas, such as in Seoul, Pusan and Taegu. Scheme of the paper is analyzed five research cases. Contents of the analysis are carried out five kinds of transformed variables for determination of rainfall distribution types and two kinds of reliability tests on unusual(extraordinary) values each rainfall durations:short durations, long durations, long durations, monthly and yearly. Rainfall depth probability had been computed methods of hydrologic amounts analysis namely logarithmic transformations or Gumbel-Chow method and so on, but in this paper it is calculated log xi, n-square root transformations by using normal distribution function and normalization of rainfall distributions is examined graphical tests and $X^2-test$(chi-square test). Furthermore, rainfall depth probability is calculated taking into account the safty factors of project life of hydraulic structures. We think it is advanced contents that considering priceless experiences, the life of structures, conditions and more problems of planning engineers and designers, proposed rainfall amounts(proposed values) are presented charts or figures.

• 소성∙가공
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• 제11권5호
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• pp.423-429
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• 2002

The limiting drawing ratio (LDR) under uniform heating of blanks was measured at the various temperature ranges between 25 and 25$0^{\circ}C$ by using two different blank shapes, square and circular blanks, and six different blank sizes with the drawing ratios(DR) of 2.4 to 2.9. The galvannealed steel sheet (SCP3CM 60/60) of 0.7mm thickness were used. The LDR at warm forming condition reached 1.2 times of that at room temperature, and the maximum drawing depth reached 1.9 times. The higher temperature was adopted, the more stable and uniform thickness strain distribution was observed. Some cases of the experimental results were compared with the analitical results using the commercial finite element method (FEM) code.

• 소성∙가공
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• 제8권3호
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• pp.221-221
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• 1999

Warm deep drawability in a square cup drawing was investigated using a newly developed high-strength steel sheet with retained austenite that was transformed into martensite during formation. For this investigation, six different temperatures between room temperature and 250℃, and five different drawing ratios ranging from 2.2 to 2.6 were considered. The results showed that the maximum drawing force and the drawing depth were affected by the change in temperature, and a more stable thickness strain distribution was observed at elevated temperatures. However, blue shortness occurred at over 200℃. FEM analysis using the LS-DYNA code was used to compare the experimental results with the numerical results for the thickness strain distribution.

• 한국해양학회지
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• 제22권3호
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• pp.119-129
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• 1987

KONOD-1 지역의 코아퇴적물은 자생기원의 스멕타이트와 크로높틸로라이트, 육지기원의 일라이트, 크로라이크 및 카오린나이트로 이루어져 있다. 스멕타이트와 크리높틸노라이트의 양은 코아깊이에 따라 증가하며, 특히 크리높틸로라이트는 생성되는 속성기간이 길어서 스멕타이트보다 더 깊은 깊이에서 나타난다. 표층으로 갈수록 육지기원 광물의 함량이 증가하여데, 이는 올리고세 말의 강한 바람의 영향 이거나 해수와 접하는 퇴적물의 용해때문인 것으로 보인다.

• Water Engineering Research
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• 제1권4호
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• pp.321-330
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• 2000

The grid-based KIneMatic wave STOrm Runoff Model(Kim, 1998; Kim, et al., 1998) which predicts temporal variation and spatial distribution of overland flow, subsurface flow and stream flow was evaluated at two watersheds. This model adopts the single overland flowpath algorithm and simulates surface and/or subsurface water depth at each cell by using water balance of hydrologic components. The model programmed by C-language uses ASCII-formatted map data supported by the irregular gridded map of the GRASS(Geographic Resources Analysis Support System) GIS and generates the spatial distribution maps of discharge, flow depth and soil moisture of the watershed.

• 소성∙가공
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• 제9권2호
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• pp.186-192
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• 2000

Some deep drawing characteristics to the elevated temperatures were investigated for the SCPI steel sheets by using the Cr-coated die. For this investigations, six steps of temperature ranges, from room temperature to 25$0^{\circ}C$, and six kinds of drawing ratio, from 2.4 to 2.9 were adopted. As a result, the limiting drawing ratio, maximum drawing force, and the maximum drawing depth were sensitively affected by the elevated temperatures, and the more stable thickness strain distribution was observed to the elevated temperatures. Some experimental results were compared with analytical results using the DYNA-3D code.

• 한국전기전자재료학회논문지
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• 제23권2호
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• pp.103-117
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• 2010

In this study, the heart rate variability(HRV) signal of operating patient was acquired according to anesthesia progress and identified to evaluation possibility of depth of anesthesia in each anesthesia stage. The HRV signal was analyzed time-frequency domain applied to Wigner-Ville distribution method, the characteristic parameters were extracted for evaluation of depth of anesthesia in each anesthesia stage. The progress of general anesthesia was divided into the states of pre-operation, induction of anesthesia, operation, awaking and post-operation.

• 한국재난정보학회 논문집
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• 제6권1호
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• pp.78-90
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• 2010

Exposure to the outside, the concrete is differential moisture distribution depending on the depth. Such a differential moisture distribution causes the differential drying shrinkage in concrete structures. This thesis is researched to compare the shrinkage of lightweight concrete depending on depth to normal concrete. It is used artificial lightweight aggregate which has 20% of pre-absorb value by lightweight concrete. When water-binder ratio is 30%, average shrinkage of lightweight concrete section decreased than normal concrete, but differential shrinkage of lightweight concrete section increased. However water-binder ratio is 40% and 50% average shrinkage and differential shrinkage of lightweight concrete section decreased than normal concrete.