• 한국해양학회지
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• v.20 no.1
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• pp.74-82
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• 1985

Exposed on the sea, the oils are affected by the combined effects of evaporation, solution, chemical oxidation, and biological decomposition. Therefore the samples were taken after artificial weathering, and they were analyzed by gas chromatography for sulfur and hydrocarbons. The measurement results of gas chromatography have shown characteristic patterns. The peaks of the lower hydrocarbons in pollutant oil decreased with time. But the chromatograms for sulfur compound analysed by FPD showed little changes with lapse of time. The hydrocarbon and sulfur compound analysis by gas chromatography can be effectively used for analyzing oils for comparative identification.

• Earthquakes and Structures
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• v.10 no.4
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• pp.811-828
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• 2016

This study aims to present nonlinear time history analysis results of double leaf cavity wall (DLCW) reinforced concrete structure exposed to shake table tests. Simulation of the model was done by a Finite Element (FE) program. Shake table experiment was performed at the National Civil Engineering Laboratory in Lisbon, Portugal. The results of the experiment were compared with numeric DLCW model and numeric model of reinforced concrete structure with unreinforced masonry wall (URM). Both DLCW and URM models have two bays and two stories. Dimensions of the tested structure and finite element models are 1:1.5 scaled according to Cauchy Froude similitude law. The URM model has no experimental results but the purpose is to compare their performance level with the DLCW model. Results of the analysis were compared with experimental response and were evaluated according to ASCE/SEI 41-06 code.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.449-451
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• 2006

With the increasing danger of personal information being exposed, a technique to protect personal information by identifying a non-user in case it is exposed. A study to construct a neural network recognizer for developing a economical and effective user protecting system. For this, time variables regarding user typing patterns from a pattern extraction device. With the variations in the standard deviation for the collected time variables, non-user patterns were generated. The recognition performance increased with the increase in the standard deviation and a higher recognition was achieved at 2.5. Also, five types of training data were generated and the recognition performance was examined as a function of the number of non-user patterns. With the increase in non-suer patterns, the recognition error quantified in the root mean square error (RMSE) was reduced. The smallest RMSE was obtained at the type 5 and 90 non-user patterns. In overall, the type 3 model yielded the highest recognition accuracy Particularly, a perfect recognition of 100% was achieved at 45 non-user patterns.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.635-638
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• 2003

This paper deals with structural behavior of reinforced concrete beams with high strength under fire and fire damaged condition. The main purpose of this study is to evaluate the residual strength of flexural members by exposure time to fire. For this purpose, six beam specimens are fabricated and experimented. Among the specimens, four specimens are exposed to the fire for 60 and 90 minutes and two specimens are control beam that is not exposed to fire. After being cooled in room temperature, the specimens are loaded to the failure. The research result shows that the main variables of the test, concrete cover and exposure time to fire are much influenced on the structural behavior and the residual strength.

• Journal of Power System Engineering
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• v.5 no.2
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• pp.57-62
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• 2001

Gas turbine performance is highly dependent on the engine performance which is closely related to the engine materials since they are exposed to severe working environments, i.e, high temperature and high stresses. For this reason, advanced materials with improved properties are required for the engine. The purpose of this research is to develop key materials technologies for aircraft industry and to tester domestic production of related parts. In this paper, the real-time prediction of high temperature creep strength and creep life for nickel-based superalloy Udimet 720(high-temperature and high-pressure the gas turbine engine materials) was performed on round-bar type specimens under pure load at the temperatures of 538, 649 and $704^{\circ}C$.

• Toxicological Research
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• v.20 no.1
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• pp.31-36
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• 2004

Against environmental stress, ceruloplasmin which is a plasma protein, are believed to play central roles in antioxidant- or peroxidase-activity in blood stream to remove free radicals, which may be caused by exposing of $\gamma$-irradiation. In human U-937 cells exposed to $\gamma$-irradiation, the levels of mRNA in ceruloplasmin gene were measured on 0, 4, 12, 24 hr after exposing by using comparative RT-PCR (Reverse transcriptase-polymerase chain reaction) which was achieved to compare with house keeping genes such as $\beta$-actin and hprt. After $\gamma$-irradiation of 100 rads or 200 rads, the total quantities of RNA were increased as dose and time dependent manner. On the contrary, the variation of mRNA expression in ceruloplasmin was not found until 4 hr after irradiation. After 12 hr and 24 hr of irradiation, the levels of mRNA in ceruloplasmin were significantly increased as dose and time dependent manner than un-exposed cells.

• Journal of Applied Reliability
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• v.16 no.1
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• pp.41-47
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• 2016

Purpose: The purpose of this study was to evaluate electrical and structural degradation of flexible CIGS sollar cell exposed to high temperature and humid atmosphere. Method: Accelerated degradation was performed for various time under $85^{\circ}C/85%RH$ and then electrical and structural properties were analyzed by 4-point probe method, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). Results: Sheet resistance of the top ITO layer increased with exposure time to the high temperature and humid atmosphere. Blunting of the protrusion morphology of ITO layer was observed for the degraded specimen, while no phase change was detected by XRD. Oxygen was detected at the edge area after 300 hours of exposure. Conclusion: Increase in electrical resistance of the degraded CIGS solar cell under high temperature and humid environment was attribute to the oxygen or water absorption.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.33-36
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• 2006

The purpose of this paper is to investigate the structural behavior of fire damaged high-strength SRC columns with polypropylene fiber. When high-strength concrete is exposed to high temperature, spalling is occurred then it leads to decrease the capacity of members. Polypropylene fiber is used to reduce the spalling of the specimens and the distinction in the behavior after fire is observed. High-strength concrete specimens were exposed to high temperatures by the ISO 834 curve. Main experimental parameters were the ratio of the contained polypropylene fiver, heating time and type of loading. Reduction rate in residual strength and stiffness is observed for the mixing of PP fiber, the heating time and eccentricity of loading.

• Journal of the Korea Concrete Institute
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• v.18 no.2 s.92
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• pp.233-238
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• 2006

In lifetime estimation, the FEM analysis method is proposed for predicting corrosion failure time of concrete structures exposed to sea-water. This study shows that the corrosion rate of rebar in artificial pore solution can be transferred to the corrosion rate of rebar in concrete using the relationship between pore volume and concrete volume by Jennings' model. And this study considered the pitting corrosion effects of reinforcement bar on corrosion failure analysis, rebar size to cover depth and nonlinear crack analysis. These analysis results have good accordance with the experimental results of Williamson's work. This methodology can be applied to lifetime prediction procedure of reinforced concrete structures and also gives more reasonable results of concrete cover failure time estimation of reinforced concrete structures exposed to sea-water.

• Journal of fish pathology
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• v.30 no.1
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• pp.51-61
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• 2017

The effect of electromagnetic field on aquatic organisms has received little attention. In the current study, the effect of 50Hz electromagnetic field on muscle histopathology of Caspian Sea Cyprinus carpio, a species of economic importance, was investigated. A total of 120 healthy fish were used in this study. They were classified randomly in one of two groups as follows: Control or unexposed EMF group and experimental group with 5 different magnetic field intensities (0.1, 1, 3, 5 and 7mT) at 2 different exposure times including 30 and 60 minutes. Fish in the experimental group were exposed only once. Two weeks after exposure, dorsal muscles sectioned transversely, stained and were examined using a light microscope. Histopathologic assessments showed significant difference between control and EMF exposed groups at both 30 min. (p<0.01) and 60 min. (p<0.001) exposure times. We report for the first time that electromagnetic field in interaction with muscular tissue of Cyprinus carpio exhibits a dual effect which depends on the field intensity, and exposure time. At short exposure time (30 min.), EMF stimulates muscle growth process. At longer exposure time (60 min.), EMF can damage muscle tissue and result in muscle necrosis. More research is required to elucidate precise mechanisms involved in muscle hypertrophy and pathologic changes.