• Journal of the Mineralogical Society of Korea
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• v.15 no.4
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• pp.259-272
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• 2002

This study was tried to interpret the important major factors controlling some physicochemical properties by comparing mineralogical and physicochemical characteristics such as pH, cation exchange capacity, Methylene Blue adsorption amount, swelling, viscosity, strength (compressional and tensile), and surface area etc. Investigated bentonite samples are five Korean samples from Dusan, Naa, Oksan, Dongyang, and Yeonil deposits and two Japanese bentonites from Tsukinuno and Tomioka deposits which were formed under a similar geological environment of the Tertiary basin. Tsukinuno bentonite is only natural Na-type bentonite and the others are all Ca-type bentonites. Most of the properties are not explained by the montmorillonite content only though the most important factor controlling the physicochemical properties is the montmorillonite content. The layer charge of montmorillonite will strongly control cation exchange capacity and Methylene Blue adsorption. Zeolite bearing bentonites show the strong alkaline character and causes the increase of cation exchange capacity, however decrease swelling, viscosity and strengths. Pyrite bearing bentonites decrease green compressional strength and wet tensile strength. The exchangeable interlayer cations control some physicochemical properties. Na-type bentonite than Ca-type shows more strong alkaline character and much more advanced swelling and viscosity. Also the size and thickness of montmorillonite flakes seem to control some physicochemical properties. Bentonite mainly composed of montmorillonite of very thin and large flakes is characterized by the very high surface area, cation exchange capacity, viscosity, swelling, Methylene Blue adsorption, green compressional strength and wet tensile strength. Domestic Dusan bentonite shows the most excellent physicochemical properties, which is due to the high content(84%) and very well crystallinity of montmorillonite.

• Journal of Korean Medical classics
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• v.3
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• pp.444-500
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• 1989

I have felt seriously a desire to study and analyse the medicine of the period of the Three Kingdoms when I thought and studied the ancient medical history. Therefore in Chapter II I inquired into the background of Politico-social and the currency of thought. In the Chapter III inquired into the system of Medical politics in the period of the Three Kingdoms. In the Chapter IV inquired into the general view of the period of the Three Kingdoms. In the Chapter V inquired into the writings of Medicine and Doctors. From this study, I reached at following-conclusions. 1. The Three Kingdoms are politically opposed to each other, but socialo culturaly cooperated, connected each other to import the technique and thought which developed in China, so generally their system and life pattern are alike. 2. On the system of medical politcics Goguryeo(高句麗) had the system of court phisician, Baek jeo(百濟) had medical doctor and collector in the Ministry of Drug which took charge of teaching and medical treatment and specially had spellchanting doctor who treat epidermic and psychological diease untreated with herb and acupuncture, Shilla(新羅) had the system of Yak chun which was charge of teaching and treatment, and had the Chimbang(針房) which assist doctor in the system of Yagchun(藥典制度). 3. The medical interchange with China made the Three Kingdoms to import the medical books. So the theory of medicine was systematized and the art of treatment developed. In the aspect of Herb the Three Kingdoms and China actively exchange their own district product. 4. The medicine of Three Kingdoms accommodated Yin Yang Ohang theory(陰陽五行說), the theory of body compose with four element(四大 : 地水火風) and the theory of life cultivation and breathing(導引養生說) with Therefore in many aspect of oriental medicine basic theory and treatment would improved. 5. The epidermic diease occurred in period of Three Kingdoms, is represented Yeok(疫), that is after all Ohn Diease(溫病), and epidermic diease, is relfected by earthquake, heavy rain, terrible droughty and eclipse of sun. The treatment of this diease did not developed in that time, we presume that there are many persons killed. 6. As the record of five starr(五星), comet(彗星) and eclipse of sun was showed, the astronomy of oriental medicine in the Three Kingdoms was high level and it became the mothers womb of Korean astronomy. 7. The medicine of the Three Kingdoms, concreted with Chinese medicine and their own ancient one, was reflect on Japanese medicine to improve the medical theory and treatment. 8. The Three Kingdoms peculiarly published Korea Nosabang(高麗老師方) Baekjyeo Shinjipbang(百濟新集方), so this independent medicine reflected on the development of natural hurb(鄕約) of the period of Korea(高麗).

• Analytical Science and Technology
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• v.24 no.4
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• pp.275-281
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• 2011

$AlPO_4$-type material was synthesized by a reaction of $Al(OH)_3$ and H3PO4 with organic templates from wastewater of detergent manufacturer. The surface of material was coated with carboxylate groups by the reaction of succinic anhydride with surface amino groups which were formed by treatment of the material with APTMS. Powder XRD patterns showed the characteristic patterns of $AlPO_4$. Morphology of the material was examined using a SEM and the functional groups were investigated by FT-IR analysis. The surface charge of a aqueous suspension was analyzed: $AlPO_4-NH_2$ has positively charged surface while $AlPO_4$-COOH has negatively charged one. They were used for the removal of toxic metals from aqueous solution. The lead ions were adsorbed on the surface by the formation of complexes with carboxylate of surface and $K_d$ was 91.1 mL/g. In conclusion, the $AlPO_4$-COOH might be applicable in the removal of toxic metal ions from aqueous system.

• The Journal of the Korea Contents Association
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• v.14 no.9
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• pp.437-449
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• 2014

In order to suggest alternative directions for the regional development of Chungcheongbukdo through social network analysis (SNA) methods, this study highlights networking features of Chungcheongbukdo-based top 300 enterprises. In particular, it has paid attention to network relationships among participating enterprises and their basic structure, all of which play pivotal roles in provincial development. Major networking features among Chungcheongbukdo-based top 300 enterprises are dichotomized between structural and positional dimensions. Firstly, in terms of structural approach, this research confirms that both relational density indices and average connectivity levels among key enterprises have been extremely low. Therefore, the exchange networks seem relatively limited. That is, two enterprises could be interconnected after 1.1 stages in average, implying that the most popular types come from direct relationship among participating enterprises. In addition, this research finds that 7 major networks hinged upon 'distributed centralization types' present active information exchange, taking in charge of brokerage roles, all of which have contributed to broader network formation. Nonetheless, as the weight of minor network outweighs that of major network, more active supporting measures should be designed.

• Archives of design research
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• v.17 no.3
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• pp.167-178
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• 2004

The purpose of this treatise is to show merits and method of establishing Lotte department store design division Online Documents Communication System through illustration of examples of intranet in which internet environment convenient to use for its openness is applied for establishing Design Online Documents Communication System for fundamentals of organization. In this connection merits and effect attainable from establishing Design Outline Documents Communication System of the enterprise as found were as follows: Firstly, it brought about reduction in workload of staffs through sharing various existing resources. It reduced redundant works and enables speedy handling of works. Secondly, it was possible to exchange viewpoints and share information by pertinent parties. Thirdly, by expediting information exchange and communication among persons in charge it was possible to improve work efficiency. Fourthly, it was possible to build and operate such system at relatively low cost on the basis of web browser. Without using any other significant instrument or equipment but by linking it to business network and using existing computer system operation was possible. Fifthly, by common sharing of work exclusive to design room through on-line it was possible to improve professionalism and convenience in data preservation. Through this treatise and survey and study on process for establishing intranet it was possible to find that there were sharing work, improving work efficiency, reducing workload, saving cost and expediting communication to a significant degree.

• Korean Journal of Comparative Education
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• v.26 no.4
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• pp.153-172
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• 2016

This study aims at comparing and analyzing early childhood education systems in both South and North Koreas and suggesting educational alternatives for integrating in various aspects based on it, in order to build directions of early childhood education system in the preparation of Unification. A comparative study on the early childhood education system in South and North Korea was done in terms of early childhood education, public education of early childhood. As a result, there were differences rather than similarities in many areas due to the differences of political ideology between the South and the North. First, early childhood is not compulsory, but becomes public in South, while it is partially compulsory and has an overall public system in North in terms of its compulsory education and Pulic education. Second, as a result of comparing operating systems depending on early childhood education institutions in the South and North, there were differences in various areas such as subjects of foundation, classification of age, operating types, etc. Third, looking at its administrative support system, two Koreas has a similarity of a overall dual system, but showed a specific difference. Fourth, its public support had a similarity that early childhood education is done free of charge in two Koreas. In light of the results of comparing the early childhood education system in South and North Korea, this study suggests the following implications. First, as part of an effort to restore similarities of the early childhood education system between two Koreas, a challenge that must be addressed with priority is to integrate early childhood education-nursery in the early childhood education for age 3-5. Second, we'll take an effort to include the early childhood education for age 3-5 in the basic disciplines with 'Making early childhood education public' being currently focused. In addition, we should an attitude to recover a similarity through mutual exchange and to have advantages of the early childhood education in two Koreas as a challenge of taking an effort to integrate the early childhood education in the South and the North various studies and debates, discussions will be made for the meaning of the early childhood education and the integration.

• KEPCO Journal on Electric Power and Energy
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• v.8 no.2
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• pp.159-179
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• 2022

Often a network becomes complex, and multiple entities would get in charge of managing part of the whole network. An example is a utility grid. While the entire grid would go under a single utility company's responsibility, the network is often split into multiple subsections. Subsequently, each subsection would be given as the responsibility area to the corresponding sub-organization in the utility company. The issue of how to make subsystems of adequate size and minimum number of interconnections between subsystems becomes more critical, especially in real-time simulations. Because the computation capability limit of a single computation unit, regardless of whether it is a high-speed conventional CPU core or an FPGA computational engine, it comes with a maximum limit that can be completed within a given amount of execution time. The issue becomes worsened in real time simulation, in which the computation needs to be in precise synchronization with the real-world clock. When the subject of the computation allows for a longer execution time, i.e., a larger time step size, a larger portion of the network can be put on a computation unit. This translates into a larger margin of the difference between the worst and the best. In other words, even though the worst (or the largest) computational burden is orders of magnitude larger than the best (or the smallest) computational burden, all the necessary computation can still be completed within the given amount of time. However, the requirement of real-time makes the margin much smaller. In other words, the difference between the worst and the best should be as small as possible in order to ensure the even distribution of the computational load. Besides, data exchange/communication is essential in parallel computation, affecting the overall performance. However, the exchange of data takes time. Therefore, the corresponding consideration needs to be with the computational load distribution among multiple calculation units. If it turns out in a satisfactory way, such distribution will raise the possibility of completing the necessary computation in a given amount of time, which might come down in the level of microsecond order. This paper presents an effective way to split a given electrical network, according to multiple criteria, for the purpose of distributing the entire computational load into a set of even (or close to even) sized computational loads. Based on the proposed system splitting method, heavy computation burdens of large-scale electrical networks can be distributed to multiple calculation units, such as an RTDS real time simulator, achieving either more efficient usage of the calculation units, a reduction of the necessary size of the simulation time step, or both.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.48 no.3
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• pp.36-45
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• 2011

An agent in collaborative e-learning has independent function for learners in any circumstance, status and task by the reasonable and general means for social learning. In order to perform it well, communication among agents requires standardized and regular information technology method. This study suggests data model as a communication tool for various agents. Therefore this study shows various agents types for collaborative learning, designation of rule for data model that enable to communicate among agents and data element of agent communication data model. A multi-agent e-learning system using like this standardized data model should able to exchange the message that is needed for communication among agents who can take charge of their independent tasks. This study should contribute to perform collaborative e-learning successfully by the application of communication data model among agents for social learning.

• Journal of Electrical Engineering and Technology
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• v.12 no.2
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• pp.594-600
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• 2017

HVDC transmission systems can be configured in many ways to take into account cost, flexibility and operational requirements. [1] For long-distance transmission, HVDC systems may be less expensive and suffer lower electrical losses. For underwater power cables, HVDC avoids the heavy currents required to charge and discharge the cable capacitance of each cycle. For shorter distances, the higher cost of DC conversion equipment compared to an AC system may still be warranted, due to other benefits of direct current links. HVDC allows power transmission between unsynchronized AC transmission systems. Since the power flow through an HVDC link can be controlled independently of the phase angle between the source and the load, it can stabilize a network against disturbances due to rapid changes in power. HVDC also allows the transfer of power between grid systems running at different frequencies, such as 50 Hz and 60 Hz. This improves the stability and economy of each grid, by allowing the exchange of power between incompatible networks. This paper proposed to establish Korean HVDC technology through a cooperative agreement between KEPCO and LSIS in 2010. During the first stage (2012), a design of the ${\pm}80kV$ 60MW HVDC bipole system was created by both KEPCO and LSIS. The HVDC system was constructed and an operation test was completed in December 2012. During the second stage, the pole#2 system was fully replaced with components that LSIS had recently developed. LSIS also successfully completed the operation test. (2014.3)

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.100.1-100.1
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• 2015

중이온가속기에서 잔류기체 분자와 가속 이온의 충돌이 발생하면 이온빔 전류의 손실을 야기하는 직접적인 효과 외에 잔류 기체분자 중에서 전리된 이온들이 반발력에 의해 용기 벽에 부딪힐 때 표면에 흡착되어 있던 기체분자들을 충격탈리(stimulated desorption)시킨다. 더 심각한 경우는 산란된 고속 이온이 용기 벽과 충돌하면서 핵반응을 일으켜 방사화 시키거나 벽에서 다량의 기체를 방출시키는 것이다. 최악의 경우에는 고속이온의 에너지에 의해 용기벽이나 부품들이 열적인 손상을 입을 수도 있다. 현재 설계 및 연구개발이 진행중인 기초과학원(IBS) RISP (Rare Isotope Science Project)의 RAON 중이온가속기는 입사기에서 실험영역까지 각 부분의 진공도 조건이 일반적으로 10-8~10-9 mbar 대에 있어서 이온빔 전류의 손실이나 전리 이온들에 의한 충격탈리는 무시할 수도 있지만 고속이온의 기체방출 수율이 ~104 정도로 높은 것을 감안할 때 고속이온의 충격탈리에 의한 압력 증가가 감내할 수준인지 검토할 필요가 있다. 압력증가는 추가적인 손실을 유발하고 이것은 다시 압력을 상승시키는 진공 불안정성(vacuum instability)을 야기할 수 있다는 축면에서 조심하는 것이 좋다고 판단된다. 고속 중이온과 잔류기체 분자와의 충돌에서 이온이 손실되는 반응에는 쿨롬(coulomb) 산란과 전하교환(charge exchange)이 있는데 전자는 후자에 비해 일반적으로 1/10000 가까이 낮아서 무시할 수 있고, 전자 포획(electron capture) 또는 전자 손실(electron loss, 이온의 전리에 해당)로 대별되는 전하교환 반응이 이온 손실을 주도하는 것으로 알려져 있다. 이 연구에서는 다양한 전하교환 반응 단면적을 아우르는 비례칙(scaling law)을 사용하여 대표적인 중이온인 U33+ 및 U79+의 손실 및 잔류 기체의 전리율을 계산하고 충격탈리에 의한 표면방출 및 압력상승을 일차적으로 고려하여 진공도 조건의 타당성을 입증하려고 한다.