• Advances in materials Research
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• v.13 no.3
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• pp.211-220
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• 2024

Polylactic acid or polylactide (PLA) is a biodegradable thermoplastic that can be produced from renewable material to create various components for industrial purposes. In 3D printing technology, PLA is used due to its good mechanical, electrical, printing properties, environmentally friendly and non-toxic properties. However, the physical properties and excellent electrical insulation properties of PLA have limited its application. In this study, with the carbon black (CB) as filler added into PLA, the lattice spacing and morphology were investigated by using X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. The physical properties of PLA-carbon composite were evaluated by using tensile test, shore D hardness test and density and voids measurement. Impedance test was conducted to investigate the electrical properties of PLA-Carbon composites. The results demonstrate that the inclusion of carbon black as filler enhances the physical properties of the PLA-carbon composites, including tensile properties, hardness, and density. The addition of carbon black also leads to improved electrical conductivity of the composites. Better enhancement toward the electrical properties of PLA-carbon composites is observed with 1wt% of carbon black in N774 grade. The N550 grade with 2wt% of carbon black shows better improvement in the physical properties of PLA-carbon composites, achieving 10.686 MPa in tensile testing, 43.330 in shore D hardness test, and a density of 1.200 g/cm3 in density measurement. The findings suggest that PLA-carbon composites have the potential for enhanced performance in various industrial applications, particularly in sectors requiring improved physical and electrical properties.

• Journal of Fisheries and Marine Sciences Education
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• v.4 no.2
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• pp.101-108
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• 1992

This study is some parts, the contents on "Course of Power Machinery and of Automated-Ship Operation", of the results of the sixth curriculum, revision study for the fisheries high schools and merchant marine high schools. In this study, it was suggested that the existing name "the Course of Marine Engine" is revised to "the Course of Power Machinery" and "the Course of Automated-Ship Operation" is newly established. The purpose of the revision of the name to "the Course of Power Machinery" is to give the course a more flexible curriculum which enables the course to bring up not only sea duty marine engineers but also shore duty power engineers. Also, the purpose of the new establishment of "the Course of Automated-Ship Operation" is to bring up automated-ship operators. The necessities for automated-ship operator is derived from the process of ship automation to reduce the number of crew to cut down the expenses. The revised parts of the organization of the professional subjects exclusively related to "the Course of Power Machinery" and "the Course of Automated-Ship Operation" are summarised as follows; (l) The Automated-Ship are newly added. (2) The Sea Training, the Fisheries Law are Disused. (3) The Introduction to Ship, the Introduction to Marine Engine and the Introduction to Marine Communication are merged into the Introduction to Ship. (4) The name of the Marine Engine, the Shipping Business are revised to the Heat Engine, the Introduction to Shipping respectively. (5) M compulsory professional subjects, the Introduction to Fisheries is suggested for the fisheries high schools and the Introduction to Shipping is suggested for the merchant marine high schools.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.3
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• pp.225-231
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• 2004

The power and scale of 950 hPa typhoon "Maemi" which struck the shore of Gosung in Kyungnam Province was same as that of 951 hPa typhoon "Saraho" in 1959. For the purpose of getting the safety of training ship "KAYA", we anchored at Jinhae Bay with riding at two anchors paid out 8 shackles of cable respectively. By the way when wind force being over 30m/s, we could not keep the safety of the ship "KAYA" by means of the holding power of an anchor only. Just by using the main engine moderately, we were able to maintain the security of the ship. The holding the main engine moderately, we were able to maintain the security of the ship. The holding power of an anchor according to the way of anchoring, the quality of sea bottom, the direction and speed of wind and current, and the length of an anchor cable were analyzed. The obtained results are summarized as follows : 1. When riding at two anchors rather than lying at single anchor we could get a good holding power. 2. There was a big difference in holding power according to the quality of the bottom. 3. It would be best anchoring in a soft mud area than in any other place as possible. 4. It would also be desirable to set anchor shackles much more than equipment number prescribed in regulation in order to get safety of a ship providing against typhoon.

• Proceedings of the KIEE Conference
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• 2008.09a
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• pp.305-307
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• 2008

Inundation of substation and ground power equipment breaks out every summer season in low-lying downtown and low-tying shore by heavy rain, typhoon and tidal wave. In case inundation excluding the exchanging cost of equipment, it occurs a great economic and social loss owing to recovery time and events of electric shock occur by inundation electrical equipment (Pad-mounted Transformer and Switch). So we research the flooding prevention countermeasures of electrical facility and Transformer Vault on Foreign. We conform the site facility and related regulation for flooding prevention on Foreign.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.423-426
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• 2007

Pohang Wind Energy Research Center (PoWER-C) is developing a 3 MW Radial Flux Permanent Magnet (RFPM) Synchronous Generator for offshore Wind Energy Converter (WEC). The rotor rpm is 15.7 and the gear ratio is set to be 92.93. The nominal generator rpm at the rated load is about 1459. To reduce the switching loss in the power electronics, the maximum frequency is limited to 100 Hz. This requirement limits the number of pole to six or eight. Permanent magnet excitation is assumed for higher energy yield and higher efficiency. In this report, the requirements and the first efforts for the physics design are described.

• Journal of Wind Energy
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• v.3 no.2
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• pp.11-17
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• 2012

An offshore(submarine) cable has been used for more than a century, however it has been used mainly for communication or power supply to near-shore island. Therefore, offshore cable has not been got more attention than other types of cable and the related standards have also not been established well. However wind farms have been shifting from land to offshore because of better wind condition. Consequently, it has been pushing up demand for offshore cable. Hence, this paper introduces the trend of offshore cable industry and related standards or recommendations only focusing on offshore wind farm. In details, the installed offshore cables in offshore wind farms, the main offshore cable makers and up to date technologies are covered. In addition, the related standards or recommendations are also analyzed and compared each other.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.4
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• pp.78-84
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• 2008

Inundation of substation and ground power equipment broke out every summer season in low-lying downtown and low-lying shore by localized heavy rain, typhoon and tidal wave. In case inundation excluding the exchanging cost of equipment, it occurs a great economic and social loss owing to recovery time and events of electric shock occur by inundation electrical facility. So we researched the installation situation of substation and power equipment and inundation loss at Flood Danger Area. And we analyzed refutation or law relating to the flood protection counterplan of US, England Australia. We present flood protection countermeasures by survey and analyzing the internal standard and his paper will be used to resent a reform proposal of electrical feinted law about flood protection.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.281-284
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• 2008

Inundation of substation and ground power equipment breaks out every summer season in low-lying downtown and low-lying shore by localized heavy rain, typhoon and tidal wave. In case inundation excluding the exchanging cost of equipment, it occurs a great economic and social loss owing to recovery time and events of electric shock occur by inundation electrical equipment(Pad-mounted Transformer and Switch). In case of installing the power equipment at flood danger territory, we are necessary to the product development, the product is that water does not come in the inside the power equipment. Product of pressure maintaining are established on the basic frame and sensor operates at the flooding occurrence and is maintained a shutting tightly structure and it is a method. The product which is produced the reliability of the product it confirmed a flooding yes or no from the condition which puts in the water tank and it verified. We estimate that loss cost which is caused by with flooding and the power failure will be diminished if it is addition to advances the reliability evaluation and a security of the flood protection product.

• Journal of Environmental Policy
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• v.10 no.3
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• pp.3-20
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• 2011

Through case studies of photovoltaic complex and wind farm construction and management, the causes of environmental and social conflicts were analyzed. Policies and measures to minimize conflicts and complement the institution were identified by analyzing successful construction and management case studies from both domestic and abroad. The causes of problems were haphazard damages to the regional environment, direct damages from power production facilities, lack of regional benefits from power production businesses, and loose environmental restrictions and management. The countermeasures to mitigate the problems at hand are to improve and strengthen the guidelines for power production businesses, secure residents' acceptability, strengthen regulations for business explanation, increase stakeholder's participation, find alternative sites, and ensure the speedy implementation of on-shore wind farms. Through these countermeasures, specific goals included in the New Renewable Energy Master Plan, such as target goals for photovoltaic and wind energy, preservation and protection of environment, and improvement of residents' acceptability, can be achieved.

• ALGAE
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• v.23 no.2
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• pp.151-162
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• 2008

Marine algal flora and community structure were seasonally examined at three sites in the vicinity of the Wolseong nuclear power plant in Korea from February to November 2006. A total of 126 seaweeds including 25 green, 31 brown, 70 red algae, and 1 marine plant were identified. The greatest number of species occurred at Jeonchonri (101 species) followed by intake (88 species) and discharge (29 species) during the study period. Of 126 seaweeds, 76 annuals and 13 warm tolerance species were recorded. Dominant species based on important value (IV > 10) were Ulva pertusa and Enteromorpha linza at intake, U. pertusa and Padina arborescens at discharge, and Sargassum horneri and Corallina pilulifera at Jeonchonri shore. Annual average biomass exhibited a wide range of variations, from 40.67g m-2 in dry weight at discharge to 133.69g m-2 at Jeonchonri. Among six functional groups, dominant group was coarsely-branched form at intake and Jeonchonri, but it was different at discharge site as filamentous form. Seaweed community structures of discharge site were distinguishable in decreasing species richness, biomass, species diversity index (H’), richness index (R), and evenness index (J’). Also, the ratios of green algae, warm tolerance species, annual algae, filamentous form and dominance index (DI) remarkably increased. Such phenomenons of discharge site are usually found under environmentally stressful conditions such as high disturbance. Thus, I can conclude that the heated effluents of nuclear power plant act as environmental stress influencing seaweed community structures and it can be detected with various community indices.