• Carbon letters
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• v.28
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• pp.72-80
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• 2018

In this study, an empirical relationship between the energy band gap of multi-walled carbon nanotubes (MWCNTs) and synthesis parameters in a chemical vapor deposition (CVD) reactor using factorial design of experiment was established. A bimetallic (Fe-Ni) catalyst supported on $CaCO_3$ was synthesized via wet impregnation technique and used for MWCNT growth. The effects of synthesis parameters such as temperature, time, acetylene flow rate, and argon carrier gas flow rate on the MWCNTs energy gap, yield, and aspect ratio were investigated. The as-prepared supported bimetallic catalyst and the MWCNTs were characterized for their morphologies, microstructures, elemental composition, thermal profiles and surface areas by high-resolution scanning electron microscope, high resolution transmission electron microscope, energy dispersive X-ray spectroscopy, thermal gravimetry analysis and Brunauer-Emmett-Teller. A regression model was developed to establish the relationship between band gap energy, MWCNTs yield and aspect ratio. The results revealed that the optimum conditions to obtain high yield and quality MWCNTs of 159.9% were: temperature ($700^{\circ}C$), time (55 min), argon flow rate ($230.37mL\;min^{-1}$) and acetylene flow rate ($150mL\;min^{-1}$) respectively. The developed regression models demonstrated that the estimated values for the three response variables; energy gap, yield and aspect ratio, were 0.246 eV, 557.64 and 0.82. The regression models showed that the energy band gap, yield, and aspect ratio of the MWCNTs were largely influenced by the synthesis parameters and can be controlled in a CVD reactor.

• Journal of Electrochemical Science and Technology
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• v.11 no.1
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• pp.33-40
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• 2020

We present a new and facile design of a high-performance Li-S cell by integrating a Li₂S-impregnated glass fiber separator together with a common sulfur cathode. We find that a considerable amount of Li₂S is consumed amidst the first charge, and most of Li₂S disappears at the end of the second charge. During the charge process, additional sulfur material is formed and contributes to a significant enhancement of the discharge capacity (~1400 mAh/g), compared with a control cell (~1260 mAh/g) without Li₂S. Moreover, the Li₂S containing cell exhibits much higher cycling stability (a 31% increase from ~840 to ~1100 mAh/g in the 100th cycle) and rate capability (a 30% increase from ~580 to ~750 mAh/g at 2 C) than the control cell. Our results indicate that adopting Li₂S-containing separator is highly effective to improving the electrochemical performances of Li-S cells.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.116-116
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• 2005

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3888-3890
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• 2013

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.210-211
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• 2005

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2006.05a
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• pp.244-249
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• 2006

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1993.11a
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• pp.78-81
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• 1993

AN EXTENSIVE RESEARCH AND DEVELOPMENT WORK WILL BE CARRIED OUT FOR THE COMMERCIALIZATION OF THE CHEMICAL HEAT PUMP SYSTEM WHICH BASED ON THE ELF AQUITAINE FRANCE PATENTED AND KIME LICENSED SOLID/GAS CHEMICAL REACTION TECHNOLOGY. TOWARD ON THAT GOAL, THE BASIC AND ENGINEERING DETAILS SUCH AS IMPEX BLOCK MATERIAL, PHYSICO-CHEMICAL AND THERMO-CHEMICAL CHARACTERISTICS OF REACTION MECHANISMS IN THE SOLID/GAS CHEMICAL REACTION HEAT PUMP SYSTEMS. THREE KIND OF APPLICATION SYSTEM ARE NOW INVESTIGATED; AIR CONDITIONING, REFRIGERATOR AND INDUSTRIAL PROCESS HEATING AND COOLING SYSTEM.

• Journal of the Korean Ceramic Society
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• v.54 no.1
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• pp.9-22
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• 2017

Many new functional materials have been studied for efficient production and storage of energy. Many new materials such as sodium-based and sulfide-based materials have been proposed for energy storage, but research on Li batteries is still dominant. Due to the influence of environmental concerns regarding nuclear energy, interest in and research on fusion power are steadily increasing. For the commercialization of nuclear fusion, a design standard based on a considerable level of physical analysis and modeling is proposed. Nevertheless, limitations of existing materials in nuclear fusion environments limit practical applications. Tritium propagation material for continuous fusion reaction is one of the core materials, and therefore research on this material is being carried out intermittently. The key material for Li-based energy storage and tritium generation is the functional material Li-M-O. In this review, a structural description of functional Li-M-O system materials and technical trends for its applications are introduced.

• Elastomers and Composites
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• v.51 no.2
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• pp.93-98
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• 2016

The composites of EVA/EPDM including aluminum trioxide (ATH) as a fire retardant were manufactured for the purpose of improving low temperature property and flame resistance in the rubbery materials. The ratio of EVA to EPDM didn't affect the flame resistance of the rubber composites. The addition of ATH resulted in increase of the flame resistance. In the evaluation of the cold resistance, the increasing EPDM content showed enhancement of cold resistance in the composites due to increasing low Tg EPDM. It was found out that tensile strengths of the composites showed a maximum value at 100 phr of ATH by reinforcing effect, but a minimum value at 200 phr of ATH owing to slippage between the flame retardant by the external stress. In the measurement of solvent resistance in tetrahydrofuran, the increasing ATH content yielded enhancement of solvent resistance by reducing swelling of the composite, and increasing EPDM content also resulted from increase of the solvent resistance by reduction of polarizability as well as increase of crosslink in the composites.

• Journal of Electrochemical Science and Technology
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• v.8 no.1
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• pp.53-60
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• 2017

Fluoroethylene carbonate (FEC) was studied as an additive for the electrolyte in lithium ion batteries with the $LiNi_{0.5}Mn_{1.5}O_4$ (LNMO) spinel cathode operating at a high potential beyond 4.7 V (vs. $Li/Li^+$). It was found that the FEC additive was electrochemically active for the $1^{st}$ charge cycle on the LNMO cathode. The presence of a large amount of FEC (more than 40 vol%) in the electrolyte caused severe side reactions with abnormally long voltage plateaus. In contrast, when the electrolyte contained less than 30 vol% FEC, the surface of the LNMO cathode was stabilized by the formation of the solid-electrolyte interphase (SEI), leading to improved cyclability. However, the resistance from the SEI limited the rate capability because of sluggish lithium transportation through the SEI and electronic insulation between the particles in the electrode.