• Applied Chemistry for Engineering
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• v.18 no.5
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• pp.522-526
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• 2007

Structural features and electrochemical performances of cokes pyrolized from oxidized cokes were examined, and compared with KOH-activated coke. Needle cokes ($d_{002}=3.5{\AA} $), having a graphene layer structure, were changed to a single phase of graphite oxide after oxidation treatment with an acidic solution having an $NaCLO_3$/needle coke composition ratio of above 7.5, and the inter-layer distance of the oxidized coke was expanded to $6.9{\AA} $ with increasing oxygen content. After heating at $200^{\circ}C$, the oxidized coke was pyrolized to the graphene layer structure with inter-layer distance of $3.6{\AA} $. However, the change of the inter-layer distance of the needle coke was not observed in the KOH activation process. On the other hand, an intercalation of electrolyte ions into the pyrolized coke, observed at first charge, occurred at 1.0 V, in which the value was lower than that of KOH-activation coke. The cell capacitor using pyrolized coke exhibited a lower internal resistance of $0.57{\Omega}$ in 1 kHz, and a larger capacitance per weight and volume of 30.3 F/g and 26.9 F/ml at the two-electrode system in the potential range 0~2.5 V than those of the cell capacitor using KOH-activation of coke. This better electrochemical performance may be associated with structure defects in the graphene layer derived from the process of the inter-layer expansion and shrinkage.

• Applied Chemistry for Engineering
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• v.7 no.6
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• pp.1132-1141
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• 1996

Heterogeneous cation exchange membrane(HCEM) was prepared with LLDPE(Linear Low Density Poly-ethylene) as binder, powdered cation exchange resins($diameter{\leq}149{\mu}m$) as ion-exchange material and glycerol as additive for electrodialysis and electrodeionization system. The weight ratio of (binder/ion exchange)/glycerol was (60%/40%)/5%, (55%/45%)/5%, (50%/50%)/5% and (40%/60%)/5%. The characterization of prepared HCEM was evaluated on mechanical, electrochemical, morphology and ion permeable properties. It was compared with commercial membrane. Electrochemical properties of HCEM of (50%/50% )/5% were very similar to value of IONPURE(commercial membrane), in which ion exchange capacity, ion transfer number and membrane resistance were to be 1.733meq/g, 0.96 and $16.08{\Omega}/cm^2$, respectively. Ion permeability of the membrane was better than that of IONPURE membrane. Compared with IONPURE membrane, the HCEM had a higher tensile strength and lower elongation and modulus, in which HCEM had tensile strength of $62.33kg/cm^2$, elongation of 87.42% and modulus of $658.53kg/cm^2$. The HCEM of (50%/50% )15% was optimum combination.

• Membrane Journal
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• v.17 no.4
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• pp.302-310
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• 2007

The effects of various system parameter on the absorption of sulfur dioxide into the absorbent liquid were investigated in a circulatory porous polymer membrane contactor. A feed gas and an absorbent used in the study were the gas mixture of air and $SO_2$ and the $Na_2SO_3$ aqueous solution, respectively. The separation of sulfur dioxide was measured in terms of the concentration of $Na_2SO_3$ absorbent, the concentration of sulfur dioxide, the feed flow rate, the absorbent velocity and the different membrane material. As the concentration of absorbent increased from 0.05 to 0.2 M, the removal efficiency increased from 74 to 100%. By increasing the concentration of sulfur dioxide from 700 to 2,500 ppm, the removal efficiency decreased from 100 to 75%. Also as the absorbent velocity increased from 2.5 to 15 mL/min, the removal efficiency increased from 85 to 100%. As the porosity of the membrane increased, the removal efficiency increased.

• Membrane Journal
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• v.17 no.4
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• pp.352-358
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• 2007

A nonporous hollow fiber membrane contactor was used to control the concentration of oxygen dissolved in an aqueous solution, which was predicted along the hollow fiber membrane using a computer simulation. The governing ordinary differential equations were derived for the occurrent flows of the feed aqueous solution and the feed gas mixture in a membrane contactor and they were numerically solved using the 5th Runge-Kutta-Verner method with a personal computer, where the program was coded utilizing a software of the Compaq Visual Fortran 6.6. It is found that the concentration of oxygen dissolved in water increases from 30 to 64 ppm as the length of the hollow fiber increases from 0.4 to 1.2 m when the membrane of fibers are equal to be 16,000; the flow rate of the feed gas is kept to be 0.536 mol/sec; its pressure is maintained to be 486 kPa; the flow rate of the water is 16.69 mol/sec. As the flow rate of the water increases from 9.26 to 26.85 mol/sec, the concentration of oxygen decreases from 40 to 20 ppm with the constant fiber length of 0.4 m. Finally, it is observed that the concentration of oxygen increases from 33 to 69 ppm as the pressure of the feed gas increases from 298 to 847 kPa.

• Clinical and Experimental Reproductive Medicine
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• v.30 no.4
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• pp.293-298
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• 2003

목 적: 인간의 배아줄기세포는 전분화능과 영속성을 가지고 있어 발생 및 분화에 관련된 기초 연구 뿐 만 아니라 재생의학, 약물검색 등에서도 매우 유용한 재료로 이용될 수 있다.본 연구에서는 유전체의 변형이 배아줄기세포주의 확립 효율에 미치는 영향을 살펴보고자 비정상적인 포배기 배아에서 내세포괴를 분리하여 배양하였다. 연구 방법: 인간의 체외수정 및 배아이식술에서 공여 받은1개 또는3개의 전핵이 관찰되는 비정상 수정란 (n=20)과 착상전 유전진단에서 이수성이 확인된 배아 (n=27)를 대상으로 하였다. 일반적인 immunosurgery 방법으로 영양배엽세포들을 제거하고 내세포괴를 분리한 후 PMEF 혹은 STO feeder 세포위에서 배양하였다. 배아줄기세포의 배양시스템을 검증하기 위해서 이미 확립된 Miz-hES1 cell line을 동시에 같은 조건 하에서 계대배양하였다. 결 과: 비정상 수정란에서 발생된 포배기 배아에서 분리한 1개의 내세포괴가 배아줄기세포와 유사한 colony를 형성하였으나, 계대배양에는 실패하였다. 이수성 배아에서 발생된 포배기 배아의 내세포괴 배양에서는 두개의 colony가 계대배양 중에 영양배엽세포의 형태로 분화되어 미분화 상태를 유지하지 못하였다. 동일한 시기와 조건 하에서 계대배양된 Miz-hES1 cell line이 미분화상태로 유지됨을 karyotyping (46, XY)과 immunophenotyping (positive in SSEA-3 and -4)으로 확인하였다. 결 론: 본 연구의 결과에서 비정상 수정란과 이수성 배아에서 발생된 포배기 배아에서 유래한 내세포괴는 배아줄기세포주 확립 및 미분화 상태 유지 능력이 매우 저조한 것으로 여겨진다. 따라서, 인간의 배아줄기세포주를 확립하는데 있어 배아의 정상여부가 중요한 요소로 작용할 것으로 생각된다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.190-196
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• 2020

FRACAS(Failure Reporting, Analysis and Corrective Action System) has been applied in various industries to improve the reliability of the systems. FRACAS is effective in improving reliability by repeating failure analysis, proper corrective action, and result verification for identified failures. However, FRACAS has many limitations in terms of process, data collection and management to be integrated into the existing development environment. In the domestic defense industry, studies on the development of FRACAS system and process improvement have been conducted to solve the difficulties of applying FRACAS, but most of them are concentrated in the operation/maintenance phase. Since FRACAS should be conducted in consideration of TLCSM(Total Life Cycle System Management), it is necessary to study the reference architecture so that FRACAS can be applied from the early design phase. In this paper, we studied the TLCSM-based integrated architecture considering the system life cycle phases, FRACAS closed-loop process, and FRACAS essentials in order to effectively apply FRACAS throughout the life cycle of defense systems. The proposed architecture was used as a reference model for FRACAS in a shipboard combat system.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.8
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• pp.547-565
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• 2009

Simulation is the imitation of some real thing, state of affairs, or process. The act of simulating something generally entails identifying certain key characteristics or behaviors of a selected physical or abstract system. And a simulator is the software or hardware tool that performs simulation tasks. When developing a simulator, the non-functional requirements such as modifiability, interoperability, and extendability should be required. However, existing studies about the simulator development focus not on such non-functional requirements but on the methodologies to build the simulation model. In this paper, we suggest the new architectural pattern for the software based simulator in consideration of such non-functional requirements. In order to define the architectural pattern, we identify the essential elements of the simulators, define relationships between them, and design the architectural structure with the elements to accommodate such non-functional requirements. According to the proposed pattern we can solve the simulation problems to combine the various simulation model components. The pattern guarantees modifiability by reconstructing the simulation model, also guarantees interoperability and extendability by adding various interfaces to the simulation model and by keeping the consistent interfacing mechanism between the simulation model components. The suggested architectural pattern can be used as the reference architecture of the simulator systems that will be developed in future.

• Korean Journal of Ichthyology
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• v.30 no.4
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• pp.232-237
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• 2018

The feeding habits of Beringraja pulchra were studied using 203 specimens collected from February 2017 to March 2018 in the coastal waters of Incheon, Korea. The size of B. pulchra ranged from 31.1 to 77.7 cm in disc width (DW) and the stomachs of 16 specimens were empty. B. pulchra was a carnivore that mainly consumed fishes and shrimps, but also ate various benthic crustaceans and other invertebrates with small amounts. The main prey items in the diets of shrimps and fishes were Crangon hakodatei and Ammodytes personatus, respectively. The proportion of fishes in prey items increased with size-related while that of shrimps decreased. With increasing disc width of B. pulchra, the mean number of preys per stomach (mN/ST) and the mean weight of preys per stomach (mW/ST) were increased.

• Journal of Service Research and Studies
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• v.8 no.3
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• pp.81-95
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• 2018

This study proposes a service model that can effectively provide users with knowledge and wisdom contents from the experience of overcoming the crisis to sustain human growth. In order to serve as a wisdom content, the necessity of the service nature is suggested and the present knowledge contents services are analyzed from the viewpoint of service nature. As a result, it is analyzed that current knowledge contents service is unidirectional, inconsistent and can not provide various related information together. In this study, we propose a wisdom contents service model that is consistent with the current service era. We propose a new wisdom contents service model that reflects the essence of service as a way to become more useful wisdom contents service. The proposed wisdom contents service model is able to provide a story and various related information out of the existing fragmentary knowledge services. This makes it easy for users to acquire and use wisdom. This study is a basic study for the development of wisdom contents service, and further research is needed on detailed discussion of wisdom contents service, analysis of service system, and suggestion of customized service through user demand survey.

• Journal of the Korean GEO-environmental Society
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• v.12 no.7
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• pp.23-29
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• 2011

The oxidation slag has been widely used in civil engineering project, whereas the reduced slag from electric furnace has yet to be applied. Consequently in order to find out the recycling method in civil engineering field, the mineral compositions of the reduced slag were analyzed and some tests on water quality were performed to estimate the potential release of toxic compounds. Slag-soil mixtures of 0, 10, 20 and 30%(dry weight) soil were prepared in lysimeter columns and the effluents were collected with the period of one, two and four week options in closed system, respectively. The result from qualitative and quantitative analysis using X-ray Diffraction(XRD) and X-ray Fluorescence(XRF) indicates that the main mineral of the reduced slag is $Ca_2(SiO_4)$, a kind of calcium silicate. Also, the leaching medium analyzed by Inductively Coupled Plasma Optical Emission Spectroscopy(ICP-OES) showed that main heavy metals such as Al, Fe and Mn are included in the reduced slag due to the effect of steel production process. It can be seen that the leachate does not violate the regulation guide line of waste material of heavy metal. Also the pH levels were increased from pH 6.9 for 0% soil to pH 10 for 30% soil. However the influence on leachate circulation period of one through four weeks was negligible.