• Journal of the Korean Electrochemical Society
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• v.9 no.3
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• pp.124-131
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• 2006

For commercialization of molten carbonate fuel cell (MCFC), it has some problems to be overcome such as decrease of porosity and thickness of the anode under the operating condition (at $650^{\circ}C$ and working pressure of more than 2 $kg_f/cm^2$). Recently, Ni-Al alloy anode has been proposed to replace the conventional Ni-Cr anode as an alternative material to resist a creep and inhibit the sintering. The objective of this research is to sinter the green sheet of Ni-Al alloy anode during single cell pre-treatment process, which has several advantages like cost down and simplification of manufacturing process. However, the Ni-Al alloy anode prepared with a conventional pre-treatment process showed the phase separation of Ni-Al alloy and formation of micropore(${\leqq}0.4{\mu}m$), resulting in low creep resistance and high electrolyte re-distribution. In order to prevent the Ni-Al alloy anode from phase-separating, nitrogen gas was used in the process of pre-treatment. Introducing the nitrogen, the phase separation from Ni-Al alloy into nickel and alumina was minimized and increased creep resistance. However, there was some micropore formation on the surface of Ni-Al alloy anode during the cell operation due to creation of lithium aluminate. Addition of more amount of electrolyte into a cell, especially at cathode, made the cell performance stable for 2,000 hrs. Consequently, it was possible to make the Ni-Al alloy anode with good creep resistance by the modified in-situ sintering technique.

• Journal of the Korean association of regional geographers
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• v.4 no.1
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• pp.77-98
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• 1998

In general, spatial imbalance in regional growth is a major cause of social and political conflicts within a state. In Korea, this inequality has functioned as a threat to the state's integration. With the economic development policies by regional industrialization over the past three decades, most of the industrial activities have been concentrated in Seoul and Pusan metropolitan areas, which are surrounded by Kyonggi, Kyongnam provinces respectively. Compared to these areas, Chonnam and Chonbuk provinces have lagged behind in economic development. Therefore, in order to increase the regional economic development of the southwestern region in Korea, the central government has been enforcing several policies aimed at regional industrialization since the 1980s. The purpose of this study focuses on the regional economic impacts of a newly established industrial estate-Yulchon industrial complex- which would act as a regional growth center in the Kwangyang bay area. The Kwangyang bay area consists of several industrial estates such as Kwangyang Iron and Steel Co. and its related industrial complex, Chuam rural industrial estate, Yeochon industrial complex, and so on. In addition, the Kwangyang container port was constructed in 1997. The Kwangyang bay area has been changing to a new industrial district in the southwestern part of Korea as a result of industrialization policies which were activated by central government. The Yulchon industrial complex, which is expected to be completed in 2001, would draw many manufacturing plants. For example, Hyundai Motors Co. has a plan to locate a new automobile assembly plant within the estate. As the plan has high probability to be realized, it will be interesting to study the effects a new automobile assembly plant and its related production linkages have on the region. This study is to estimate the expected structural characteristics of automobile production activities in Yulchon. The following details will be discussed: the regional economic impacts of a new automobile industry in Yulchon industrial complex, the production linkage formation via hierarchical subcontracting systems, the alternative strategies to promote the growth of regional economies, and the scheme to improve the auto-parts and components industry in Kwangju and Chonnam provinces by establishing auto-mobile production function. Automoblie industry generally gives great influences on not only regional economies but the related industries, for example, the firms producing automotive components. If a new plant producing automobiles and its related firms producing components are to be established in Yulchon, they will affect on the regional development directions and change the regional characteristics of industrial structure. In order to increase the spread effects of the new industry in Yulchon industrial complex, almost all of the automobile production processes must be organized concurrently within a limited range of distance. There is an imperative that the co-operation system should be structured between the assembly firm and many firms producing its components. In addition to those, it would be required such as the effective division of labors between the firms, much more capabilities in the technical innovations, and the reconstruction of interrelationship between the labor unions and the firms' managers.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2000.06a
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• pp.16-23
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• 2000

The increasing functional needs of top-quality printing papers and packaging paperboards, and especially the rapid developments in electronic printing processes and various computer printers during past few years, set new targets and requirements for modern paper quality. Most of these paper grades of today have relatively high filler content, are moderately or heavily calendered , and have many coating layers for the best appearance and performance. In practice, this means that many of the traditional quality assurance methods, mostly designed to measure papers made of pure. native pulp only, can not reliably (or at all) be used to analyze or rank the quality of modern papers. Hence, introduction of new measurement techniques is necessary to assure and further develop the paper quality today and in the future. Paper formation , i.e. small scale (millimeter scale) variation of basis weight, is the most important quality parameter of paper-making due to its influence on practically all the other quality properties of paper. The ideal paper would be completely uniform so that the basis weight of each small point (area) measured would be the same. In practice, of course, this is not possible because there always exists relatively large local variations in paper. However, these small scale basis weight variations are the major reason for many other quality problems, including calender blacking uneven coating result, uneven printing result, etc. The traditionally used visual inspection or optical measurement of the paper does not give us a reliable understanding of the material variations in the paper because in modern paper making process the optical behavior of paper is strongly affected by using e.g. fillers, dye or coating colors. Futhermore, the opacity (optical density) of the paper is changed at different process stages like wet pressing and calendering. The greatest advantage of using beta transmission method to measure paper formation is that it can be very reliably calibrated to measure true basis weight variation of all kinds of paper and board, independently on sample basis weight or paper grade. This gives us the possibility to measure, compare and judge papers made of different raw materials, different color, or even to measure heavily calendered, coated or printed papers. Scientific research of paper physics has shown that the orientation of the top layer (paper surface) fibers of the sheet paly the key role in paper curling and cockling , causing the typical practical problems (paper jam) with modern fax and copy machines, electronic printing , etc. On the other hand, the fiber orientation at the surface and middle layer of the sheet controls the bending stiffness of paperboard . Therefore, a reliable measurement of paper surface fiber orientation gives us a magnificent tool to investigate and predict paper curling and coclking tendency, and provides the necessary information to finetune, the manufacturing process for optimum quality. many papers, especially heavily calendered and coated grades, do resist liquid and gas penetration very much, bing beyond the measurement range of the traditional instruments or resulting invonveniently long measuring time per sample . The increased surface hardness and use of filler minerals and mechanical pulp make a reliable, nonleaking sample contact to the measurement head a challenge of its own. Paper surface coating causes, as expected, a layer which has completely different permeability characteristics compared to the other layer of the sheet. The latest developments in sensor technologies have made it possible to reliably measure gas flow in well controlled conditions, allowing us to investigate the gas penetration of open structures, such as cigarette paper, tissue or sack paper, and in the low permeability range analyze even fully greaseproof papers, silicon papers, heavily coated papers and boards or even detect defects in barrier coatings ! Even nitrogen or helium may be used as the gas, giving us completely new possibilities to rank the products or to find correlation to critical process or converting parameters. All the modern paper machines include many on-line measuring instruments which are used to give the necessary information for automatic process control systems. hence, the reliability of this information obtained from different sensors is vital for good optimizing and process stability. If any of these on-line sensors do not operate perfectly ass planned (having even small measurement error or malfunction ), the process control will set the machine to operate away from the optimum , resulting loss of profit or eventual problems in quality or runnability. To assure optimum operation of the paper machines, a novel quality assurance policy for the on-line measurements has been developed, including control procedures utilizing traceable, accredited standards for the best reliability and performance.

• Korean Journal of Heritage: History & Science
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• v.34
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• pp.20-58
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• 2001

In order to unravel the characteristics of arms used in the 'Three Kingdoms,' Kokuryo, Silla and Paikje. the classification and the developing procedures of the arms should be first discussed. At first, the basic arms of the soldiers of Three Kingdoms were iron swords, iron spearheads, and bows. During that period, swords attached a ring pommel were commonly used. But after 5A. D. a sword with a decoration pommel appeared. Infantry generally used iron spearheads. From the late 4A. D. the long spearheads were broadly used in cavalry battles. In the late 6A. D. infantry mainly used long spearheads, and this resulted in the foundation of long spearheads units. There were two kinds of bows: Short Bow whose arch is small and Long Bow whose arch is long. It is known that the Short Bow was widely used in Kokuryo and Paikje up to 5A. D. In the early era, infantry used Long Bow, yet it was vastly used after 6A. D. when a castle's strategical value was great and defending a castle was. significant. Above mentioned, as basic combat weapons, iron spearhead and bow were fundamental. In particular, the spearhead was the essential weapon to a soldier. Yet, arrow gun and hook-shape cutters were important weapons. Especially, after 6A.D., when a castle became strategically pivotal in military, the arrow gun became the important weapon. This resulted in the foundation of arrow gun units. Hook-shape cutters were used to snatch horsemen or to climb up to fall the castle. Yet, the cutter was not the Three Kingodoms' basic weapon. In addition, the three stages of arms development in the Three Kingdoms are formation stage, development stage, and settlement stage. The formation stage was the period when premitive military unit appeared in the Three Kingdoms. It ranged from 1B. C. to the mid 3A. D. At that time according to regions. there were two weapon systems operating: North area including Kokuryo and the northern part of Paikje and South area including Silla, Kaya and the southern part of Paikje. ln North area a sword with a ring attached at the end of the holder, iron spear with neck and mid-size flat holder and iron arrowhead with an extension to fix, were used. In this period, during a war calvary units were mostly used and their weapon systems seemed possibly to succeed in that of Kochosun. In the development stage, when LoLang's influence on surroundings became weak, Koguryo, Paikjae and Silla had directly contacted each other. In the late 3A.D. to the early 6A.D., Silla achieved a drastic improvement in weapon system. This was the period when Kokuryo played a leading role in arms race. Kokuryo's arms manufacturing techniques passed onto Silla, Kaya and Paikje. In combat strategy a joint operation between infantry and calvary prevailed even if their military tactics were different. In a calvary battle heavily armed horsemen played import roles at this period. The horsemen and even horses were heavily guarded with iron armors. After all, the appearance of fully armed horsemen implies the very need of powerful destructive forces in weapon system. At that time, basic weapons were a big sword with a ring attached at the end of the holder, swallow's tail-shape spear with neck, and iron spearhead with neck and an extension. The settlement stage began at the mid 6A.D., when it was the revolutionary period in the arms development history. Of course, actual proofs and picture documents were not sufficient enough to penetrate full scale of the weapon system. But, according to historical circumstances and historic records, it is very certain that this period was the peak in arms development. In this period special military units, such as infantry-calvary companies, Archery units and Long spear units, that executed particular duties with special weapons, were founded. This became the characteristics of the settlement stage.

• Korean Chemical Engineering Research
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• v.60 no.1
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• pp.86-92
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• 2022

Recently, the bio-healthcare market is enlarging worldwide due to various reasons such as the COVID-19 pandemic. Among them, biometric measurement and analysis technology are expected to bring about future technological innovation and socio-economic ripple effect. Existing systems require a large-capacity battery to drive signal processing, wireless transmission part, and an operating system in the process. However, due to the limitation of the battery capacity, it causes a spatio-temporal limitation on the use of the device. This limitation can act as a cause for the disconnection of data required for the user's health care monitoring, so it is one of the major obstacles of the health care device. In this study, we report the concept of a standalone healthcare monitoring module, which is based on both triboelectric effects and electromagnetic effects, by converting biomechanical energy into suitable electric energy. The proposed system can be operated independently without an external power source. In particular, the wireless foot pressure measurement monitoring system, which is rationally designed triboelectric sensor (TES), can recognize the user's walking habits through foot pressure measurement. By applying the triboelectric effects to the contact-separation behavior that occurs during walking, an effective foot pressure sensor was made, the performance of the sensor was verified through an electrical output signal according to the pressure, and its dynamic behavior is measured through a signal processing circuit using a capacitor. In addition, the biomechanical energy dissipated during walking is harvested as electrical energy by using the electromagnetic induction effect to be used as a power source for wireless transmission and signal processing. Therefore, the proposed system has a great potential to reduce the inconvenience of charging caused by limited battery capacity and to overcome the problem of data disconnection.

• Journal of Korea Port Economic Association
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• v.38 no.2
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• pp.81-93
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• 2022

Since 2008, China's shipping industry has been in a slump, with shipbuilding orders falling sharply, and high-growth excess capacity has become increasingly apparent, leaving many firms with sharply reduced orders at risk of bankruptcy and shutdown. To ensure the development of the shipbuilding industry and enhance the international competitiveness of the shipbuilding industry, it is necessary to analyze the present situation of the shipbuilding industry and the financial situation of the shipbuilding enterprises. And analyzing the problems faced by enterprises from the perspective of capital structure is very meaningful to the shipbuilders with high capital operation. We are trying to analyze the determinants of capital structure of China's shipbuilding listed companies. 30 listed Chinese shipbuilding and listed companies have been designated as sample companies that can obtain financial statements for 13 consecutive years. They also divided 30 sample companies into shipbuilding, shipbuilding-related manufacturing, and shipbuilding-related transportation. Dependent variable is the debt level of the year, independent variable includes the debt level of the previous year, fixed asset ratio, profitability ratio, depreciation cost ratio and asset size. The regression model of the panel used to analyze determinants is capital structure. The results of the empirical analysis are as follows. First, a fixed-effect model for the entire entity showed that the debt-to-equity ratio and the size of the asset in the previous period had a positive effect on the debt-to-equity ratio in the current period. Second, the impact of the profitability ratio on the debt level in the prior term also supports the capital procurement ranking theory rather than the static counter-conflict theory. Third, it was shown that the ratio of the depreciation of the prior term, which replaces the non-liability tax effect, affects the debt-to-equity ratio in the current period.

• Journal of the Korean Society of Earth Science Education
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• v.16 no.2
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• pp.210-223
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• 2023

This study developed elementary and middle school career education programs linked to science subjects and local natural resources, and explored learning effects and implications for developing and operating career programs. In order to achieve the research purpose, a 10-hour career education program using local natural and social resources was developed and applied to 25 elementary and middle school students in rural areas. As a result of the study, most of the elementary and middle school students who participated in this study were not well aware of the natural and social resource value of the area where they lived. Therefore, when developing and operating a regional-based career education program for elementary and middle school students in rural areas, it is necessary to operate a separate teaching/learning activity time so that students can fully know the natural and social information and resource values of the region. In addition, in order to enhance students' participation and interest in career education programs, it is necessary to organize the operation of the program in groups, not individuals, and to guide students in detail by dividing the program's performance process into several sub-steps. Finally, the core material of regional-linked career education-related programs focused more on their own content, that is, agricultural products grown by parents, and future job settings were higher in start-ups that directly operate companies such as travel agencies and manufacturing companies. Given the recent emphasis on career education in the curriculum, it is suggested that local students should pay more attention to finding materials with local resource value in the field of geoscience, which is closely related to natural resources, and developing and operating them as career education programs linked to local resources.