• Title/Summary/Keyword: volume integral method

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Thermal and Electrical Behaviors of Polyethylene Oxide/Polyaniline Fibers Prepared by Electrospinning Method (전기방사법에 의해 제조된 폴리에틸렌옥사이드/폴리아닐린 섬유의 열적 및 전기적 거동)

  • Kim, Seok;Cho, Mi-Hwa;Park, Soo-Jin
    • Applied Chemistry for Engineering
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    • v.17 no.1
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    • pp.16-21
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    • 2006
  • In this study, PEO blend fibers mixed with polyaniline (PANI)/10-camphor sulfonic acid (CSA) and PANI/dodecylbenzene sulfonic acid (DBSA) were electro spun to investigate the influence of PANI content. CSA and DBSA were used as a functionalized doping acid having a bulky volume. PANI/PEO blend solution was prepared by dissolving PEO and PANI doped with CSA or DBSA. The thermal properties were measured by thermogravimetric analyzer (TGA). As a result, with increasing of the PANI content in PANI/CSA and PANI/DBSA, although initial decomposition temperature (IDT) was decreased, thermal stability was increased due to the increase of $A^*{\cdot}K^*$ and integral procedural decomposition temperature (IPDT). The electrical conductivities measured by the 4-probe method. The electric conductivity was increased with increasing of PANI content in PANI/CSA and PANI/DBSA. However, electrical conductivity did not change significantly beyond 30% content of PANI. From CV results, PANI/CSA showed the better defined peak shpae and higher peak current density compared to PANI/DBSA. This was probably related to the slightly higher electrical conductivity or better morphology for easy charge transfer in the case of PANI/CSA.

World Logistics Evolution & Marketing Strategy for Korea's Enhanced Port Competition (세계물류발전과 한국의 항만경쟁력 강화를 위한 마케팅 전략)

  • Gim, Jin-Goo
    • Journal of Korea Port Economic Association
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    • v.24 no.4
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    • pp.363-384
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    • 2008
  • This study aims at improving Korea's competitiveness in port logistics through marketing strategy with integrating the conceptual approach into the empirical one and combining both the oldest military treatise and the newest evaluating model in social science that was applied by the HFP(hierarchical fuzzy process) model enhanced by the KJ method. The empirical results of this study show Busan in the middle among subject ports. At present, Korea plays a reciprocal role in the port market in East Asia, but in the medium- and long-term, Korea's ports will vie together with most major ports in the East Asian region. A descriptive investigation shows that Korea's developing tasks in port logistics must be considered in the context of the direction for developing port policies, the necessity of expanding port facilities in the capital region, securing the sufficient traffic volume through the establishment of the hinterland linking system and its positive utilization, and reforming the direction for developing the global logistics through increased port competitiveness. In the short- and medium-term, Korea must use the opportunity factor of 'Growth and open door policy of China' as a geoeconomic advantage and to utilize Korea's ports as a gate to Chinese foreign trade. With the rise of China's economy, China also plays a significant role in both port and airport markets. Hence, the linking system between the two must be established to meet the expanding traffic volume, especially in the capital area. Moreover, it is necessary for Korea to secure port logistics through the establishment of the hinterland linking system and its positive utilization. The great accomplishment of this paper is to present strategies to increase Korea's port competitiveness in the rapidly changing environments of world logistics with the focus on both the oldest military strategic treatise and the newest empirical method in social science. In order to reinforce this study, it needs further compensative research because the evaluation structure could be subdivided with more extensive and precise criteria.

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A Study on Estimating Optimal Tonnage of Coastal Cargo Vessels in Korea (우리나라 연안화물선의 적정선복량 추정에 관한 연구)

  • 이청환;이철영
    • Journal of the Korean Institute of Navigation
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    • v.13 no.1
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    • pp.21-53
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    • 1989
  • In the past twenty years, there has been a rapid increase in the volume of traffic in Korea due to the Korean great growth of the Korean economy. Since transformation provides an infrastructure vital to economic growth, it becomes more and more an integral part of the Korea economy. The importance of coastal shipping stands out in particular, not only because of the expansion limit on the road network, but also because of saturation in the capacity of rail transportation. In spite of this increase and its importance, coastal shipping is falling behind partly because it is givenless emphasis than ocean-going shipping and other inland transportation systems and partly because of overcompetition due to excessive ship tonnage. Therefore, estimating and planning optimum ship tonnage is the first take to develop Korean coastal shipping. This paper aims to estimate the optimum coastal ship tonnage by computer simulation and finally to draw up plans for the ship tonnage balance according to supply and demand. The estimation of the optimum ship tonnage is peformed by the method of Origin -Destimation and time series analysis. The result are as follows : (1) The optimum ship tonnage in 1987 was 358, 680 DWT, which is 54% of the current ship tonnage (481 ships, 662, 664DWT) that is equal to the optimum ship tonnage in 1998. this overcapacity result is in excessive competition and financial difficulties in Korea coastal shipping. (2) The excessive ship tonnage can be broken down into ship types as follows : oil carrier 250, 926 DWT(350%), cement carrier 9, 977 DWT(119%), iron material/machinery carrier 25, 665 DWT(117%), general cargo carrier 17, 416DWT(112%). (3) the current total ship crew of 5, 079 is more than the verified optimally efficient figure of 3, 808 by 1271. (4) From the viewpoint of management strategy, it is necessary that excessive ship tonnage be reduced and uneconomic outdated vessels be broken up. And its found that the diversion into economically efficient fleets is urgently required in order to meet increasing annual rate in the amounts of cargo(23, 877DWT). (5) The plans for the ship tonnage balance according to supply and demand are as follows 1) The establishment of a legislative system for the arrangement of ship tonnage. This would involve; (a) The announcement of an optimum tonnage which guides the licensing of cargo vessels and ship tonnage supply. (b) The establishment of an organization that substantially arrangement tonnage in Korea coastal shipping. 2) The announcement of an optimum ship tonnage both per year and short-term that guides current tonnage supply plans. 3) The settlement of elastic tariffs resulting in the protect6ion of coastal shipping's share from other tonnage supply plans. 4) The settlement of elastic tariffs resulting in the protection of coastal shipping's share from other transportation systems. 4) Restriction of ocean-going vessels from participating in coastal shipping routes. 5) Business rationalization of coastal shipping company which reduces uneconomic outdated vessels and boosts the national economy. If we are to achieve these ends, the followings are prerequisites; I) Because many non-licensed vessels are actually operating and threatening the safe voyage of the others in Korea coastal routes, it is necessary that those ind of vessels be controlled and punished by the authorities. II) The supply of ship tonnage in Korean coastal routes should be predently monitored because most of the coastal vessels are to small to be diverted into ocean-going routes in case of excessive supply. III) Every ship type which is engaged in coastal shipping should be specialized according to the characteristics of its routes as soon possible.

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