• Carbon letters
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• v.13 no.3
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• pp.157-160
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• 2012

In this work, iron oxide ($Fe_3O_4$) nanoparticles were deposited on multi-walled carbon nanotubes (MWNTs) by a simple chemical coprecipitation method and $Fe_3O_4$-decorated MWNTs (Fe-MWNTs)/polypyrrole (PPy) nanocomposites (Fe-MWNTs/PPy) were prepared by oxidation polymerization. The effect of the PPy on the electrochemical properties of the Fe-MWNTs was investigated. The structures characteristics and surface properties of MWNTs, Fe-MWNTs, and Fe-MWNTs/PPy were characterized by X-ray diffraction and X-ray photoelectron spectroscopy, respectively. The electrochemical performances of MWNTs, Fe-MWNTs, and Fe-MWNTs/PPy were determined by cyclic voltammetry and galvanostatic charge/discharge characteristics in a 1.0 M sodium sulfite electrolyte. The results showed that the Fe-MWNTs/PPy electrode had typical pseudo-capacitive behavior and a specific capacitance significantly greater than that of the Fe-MWNT electrode, indicating an enhanced electrochemical performance of the Fe-MWNTs/PPy due to their high electrical properties.

• Proceedings of the KIEE Conference
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• 1993.11a
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• pp.198-200
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• 1993

This paper represents the experimental results of electrohrdrodynamic(EHD) micropump driven by traveling- wave voltage. We fabricated 60 electrodes array with $100{\mu}m$ width and $100{\mu}m$ interval on the pyrex glass. On that glass we fabricated the micro channel which had the cross section of 3mm by 0.5mm. This pump was driven by 6 phase square traveling-wave voltage. We used the corn oil for experiments and increased the temperature of fluid by resistive heater. An optical microscope with CCD camera and monitor was used for observation. The fluid velocity was large for the large driving voltage and the high temperature. This EHD pump had the fluid velocity in specific frequency (near 1Hz) which had relation to the charge relaxation time in that oil.

• ETRI Journal
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• v.38 no.2
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• pp.252-259
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• 2016

Di(1-aminopyrene)quinone (DAQ) as a quinone-containing conducting additive is synthesized from a solution reaction of 1-aminopyrene and hydroquinone. To utilize the conductive property of DAQ and its compatibility with activated carbon, a composite electrode for a supercapacitor is also prepared by blending activated carbon and DAQ (3:1 w/w), and its supercapacitive properties are characterized based on the cyclic voltammetry and galvanostatic charge/discharge. As a result, the composite electrode adopting DAQ exhibits superior electrochemical properties, such as a higher specific capacitance of up to $160F{\cdot}g^{-1}$ at $100mV{\cdot}s^{-1}$, an excellent high-rate capability of up to $1,000mV{\cdot}s^{-1}$, and a higher cycling stability with a capacitance retention ratio of 82% for the 1,000th cycle.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10b
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• pp.318-323
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• 1992

The improvement of the production capability of multi PCB assembly line can not be simply done by improving the capacities of each assembly robot cells but must be done by controlling the production line effectively with the line host computer which controls over the whole assembly line. A real time production control, a real time model change and a real time trouble shooting compose the specific concepts of this technique. In this paper, we present and analyze the definition and application method of real time assembly concept. The meaning of real time model change, troubles and error sooting and its algorithm will be introduced. Also, the function of the host computer which is in charge of all of many different tasks mentioned above and the method are presented. The improvement of the productivity is mainly focused on the efficiency of multi-PCB production control. The importance of this aspect is gradually increasing, which we have presented the analysis and the solution.

• Carbon letters
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• v.15 no.2
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• pp.113-116
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• 2014

Due to their morphology, electrochemical stability, and function as a conducting carbon matrix, graphene nanosheets (GNS) have been studied for their potential roles in improving the performance of sulfur cathodes. In this study, a GNS/sulfur (GNS/S) composite was prepared using the infiltration method with organic solvent. The structure, morphology and crystallinity of the composites were examined using scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The electrochemical properties were also characterized using cyclic voltammetry (CV). The CV data revealed that the GNS/S composites exhibited enhanced specific-current density and ~10% higher capacity, in comparison with the S-containing, activated-carbon samples. The composite electrode also showed better cycling performance for multiple charge/discharge cycles. The improvement in the capacity and cycling stability of the GNS/S composite electrode is probably related to the fact that the graphene in the composite improves conductivity and that the graphene is well dispersed in the composites.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1685-1687
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• 1996

Recently, conducting polymer has been much attracted as novel materials because of its electronic behavior and functional application by doping process. In this paper, we electrochemically synthesized polyaniline films under potential sweep conditions, which exhibit high electric conductivity about 200 S/cm. Specific energy of 600 Wh/kg and Ah efficiency 98% were achieved during the charge/discharge cycling using liquid electrolyte system. On the other hand, consequences of the cycling were 260 Wh/kg and 95% Ah efficiency using polyethylene oxide(PEO) based solid-state electrolyte system.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1603-1605
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• 1996

We have studied the static electricity and optical retardation generated by rubbing the surfaces of polyimide (PI) and polyamide (PA) films. The static electricity increases with the rubbing strength (RS) and varies with the different PI films. We also investigated how the differences in the rubbing fabric affects the magnitude of the induced static electricity; the order of this effect is nylon > rayon > cotton. The induced static electricity is not only directly related to the values of the specific resistivity of the rubbed PI films, but also the RS and the ability of the rubbing fabric to generate and add a static electric charge. The order of the optical retardation produced by the rubbing fabraic on rubbed PI films is nylon > rayon > cotton, coinciding with the order of the generated static electricity.

• Korean Institute of Interior Design Journal
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• v.13 no.6
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• pp.150-157
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• 2004

The Furniture Industry is, which is taking Charge of the large Portion of environmental Pollution as a nun Consumer of Resources, therefore, in a Furniture Design, active Argument of the Researches and the related Constituents to the Design and Material is very absolutely required recently The Furniture Design which Ecology was applied to can minimize the environmental Burden through the Resources and Energy Consumption Reduction and cyclic Utilization within the Earth Ecosystem, and proceed to the Presentation of the Possibility to solve the recent environmental Problems. This Study was written as part of the first Step in the Development of independent Eco-Label System and environmental Criteria for Furniture and national Furniture Industries. It contains the Definition of Furniture, ecological Design and ecological Furniture (Chapter2). and Chapter 3 Presents Characteristics of ecolo91cal Furniture. Chapter 4 Provides a Summary of the specific Criteria on a Materials used for Furniture Design with the relevant environmental Issues in the Life Cycle of Furniture, and also health 8t safety related Issues and performance Issues.

• Journal of Advanced Marine Engineering and Technology
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• v.23 no.1
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• pp.25-32
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• 1999

This study was carried out to reduce NOx emissions from diesel engine and to investigate the variation of engine performance using the water injection. In this study the water was extracted from the exhaust gas and injected directly into the intake port with the inlet charge. The water condensing system operated as a closed system without any supplementary water supply. The experimental parameters such as the revolution the torque and the water injection rate are varied and the result from this experiment found the significant NOx reduction whereas the smoke emission increases as water/air ratio increases as the cases like the EGR. In spite of increasing the quantity of the water injection the engine output was slightly decreased and the specific fuel consumption was increased as was anticipated. Especially the system was founded to be effective on the reduction of the NOx emissions at the high load region relatively.

• Journal of Information Technology Services
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• v.19 no.2
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• pp.37-47
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• 2020

A significant proportion of information subjects experience information security breaches, and the number of reports and counseling cases of personal information infringements is increasing. Increased awareness of the importance of information security has raised interest in the personnel in charge of such tasks. However, hiring excellent new workers and preventing turnovers in information security remain unresolved. In this paper, by modeling the job career path of information security workforce as a Markov chain, we analyze the workforce turnover process and long-term turnover trends by information security jobs, and further analyze the number and duration of turnovers required to engage in specific jobs. The results of this study are expected to be a reference to balancing the supply and demand of information security workers for the government and to ensuring efficient management of the workforce for businesses.