• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.1
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• pp.43-48
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• 2009

The fatigue crack growth behavior of high strength X80 pipeline steel was investigated with compact tension specimens that crack growth directions were aligned either parallel or normal to the rolling direction of the pipeline. Also, the fatigue crack growth rates for welded joint of X80 pipeline steel were investigated with compact tension specimens that crack growth directions were aligned either parallel or normal to the welding line. The experimental results indicated the fatigue crack growth behavior was markedly different in three zones, weld metal, heat affected zone and base metal of welded joints. There was a trend toward increment in the fatigue life of weld metal and heat affected zone as compared with the X80 pipeline steel.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.2
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• pp.120-130
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• 2016

In general, a series of ship steering motions is composed of a combination of translational motions and rotational motions of the ship. In particular, a series of rotational motions frequently occurs in narrow areas such as ports and canal zones. In this paper, a method was suggested for composing an integrated control algorithm based on the jog dial as a command instrument for rotational motion control. In order to realize the rotational motions, several algorithms were suggested for generating rotational commands, for selecting motion variables, for choosing reference input values for the motion variables, for computing required accelerations and thrusts, and for allocating thrusts to actuators. A simulation program was compiled to execute simulations for three rotational motions. Finally, the effectiveness of the suggested method was verified by analyzing the simulation results.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.3
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• pp.792-796
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• 2005

Disk assays on the compounds (10 and 12) showed both to have antifungal activity against the dermatophytic fungus Trichophyton mentagrophytes ATCC 28185, (1 and 3 mm inhibition zones at $60\;{\mu}g/disc$), but not against the Gram-positive bacterium B. subtilis or the Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa or fungi Cladosporium resinae and Candida albicans. However, the compound (13) did not show against antifungal activity. The geranyloxy compounds (10, 12, and 13) were cytotoxic to P388 murine leukaemia cells ATCC CCL 46 P388D1, ($IC_50$ >6,250 ng/mL at $7.5\;{\mu}g/disc$). These results suggest that The geranyloxy compounds possesses antimicrobial and antitumor activities.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.3
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• pp.160-165
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• 2007

Exhaust manifold is generally subjected to thermal cycle loadings ; at hot condition, large compressive plastic deformations are generated, and at cold condition, tensile stresses are remained in highly deformed critical zones. These phenomena originate from that thermal expansions of the runners are restricted by inlet flange connected to the cylinder head, because the former is less stiff than the latter and, the temperature of the inlet flange is lower than that of the runners. Therefore, due to the repetitions of thermal deformation, leakage problems could be occur between inlet flange and cylinder head. In this study, we obtained pressure distributions along gasket bead lines from the finite element analysis and compared to the test results. It shows a good agreement between numerical and experimental results.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.11a
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• pp.283-287
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• 2004

Arc welding is sometimes used to repair damaged cast iron parts in diesel engine for driving a ship. In this case cola arc welding. is good for. saving the time and results in good repairing. But if some difference in hardness on welding zones made with AWS E Ni-CI and NiFe-CI. happen, repaired parts would be cracked in a short. In order to overcome this default, the study is performed on varying preheating temperature of welding parts, selecting welding rod and welding work way. The result will be used on ship's repair working shop.

• Journal of Hydrogen and New Energy
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• v.22 no.6
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• pp.895-904
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• 2011

Stratified charge has been thought as one of the ways to avoid a sharp pressure rise on HCCI combustion. The purpose of this study is to evaluate the potential of stratified charge for reducing PRR on HCCI combustion. The pre-mixture with thermal, mixing and EGR stratifications is charged in Rapid Compression Machine. After that, the pre-mixture is compressed and in that process, in-cylinder gas pressure and temperature are analyzed. Additionally numerical calculation with multi-zones modeling is run to know the potential of stratified charge for reducing PRR.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.6
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• pp.810-812
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• 2014

In this paper, a hagwon-bus boarding danger warning system based on computer vision is proposed to protect children from an accident causing injuries or death. Three zones are defined and different algorithms are applied to detect moving objects. In zone 1, a block-based entropy value is calculated using the absolute difference image generated by the absolute differential estimation between background image and incoming video frame. In zone 2, an effective and robust motion object tracking algorithm is performed based on the particle filter. Experimental results demonstrate the efficient and effectively of the algorithm for moving object inspection in each zone.

• International Journal of Naval Architecture and Ocean Engineering
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• v.9 no.1
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• pp.66-76
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• 2017

This paper is concerned with investigating the plastic material properties of steel plate formed by line heating method, and is aimed at implementing more rational design considering the accidental limit states such as collision or grounding. For the present study, line heating test for marine grade steel plate has been carried out with varying plate thickness and heating speed, and then microscopic examination and tensile test have been carried out. From the microscopic, it is found that the grain refined zones like ferrite and pearlite are formed all around the heat affected zone. From the tensile test results, it is seen that yield strength, tensile strength, fracture strain, hardening exponent and strength coefficient vary with plate thickness and heat input quantity. The formulae relating the material properties and heat input parameter should be, therefore, derived for the design purpose considering the accidental impact loading. This paper ends with describing the extension of the present study.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.1
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• pp.128-134
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• 2012

This paper gives an overview of the requirements for electrical equipment in potentially explosive atmospheres and describes how these are applied to electrical machines and drives in hazardous areas. The method by which equipment can be shown to be safe in a whole range of gases, by testing in a single test gas, is covered. It is shown how the more recently introduced methods of protection for hazardous areas, increased safety and nonsparking, are ideally suited to AC machines and drives. A novel method of measuring the fullload temperature rise of electrical machines for hazardous, and other areas, without the need to connect a mechanical load to the machine's drive shaft is explained.

• Journal of Electrical Engineering and Technology
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• v.9 no.4
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• pp.1290-1295
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• 2014

In this paper, various configurations of octagonal wound transformer core topology, which has previously proved advantages on conventional wound cores, are studied. Each configuration has different joint types and different placement of joint zones on the core. Magnetic flux distributions and power losses of each configuration are analyzed and compared. Comparisons are based on both 2D&3D finite element simulations and experimental studies. The results show that, joint types and their placements on the core cause local flux accumulations and dramatically affect power loss of the core.