• Carbon letters
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• v.13 no.1
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• pp.51-55
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• 2012

In this work, expanded graphite (EG)-reinforced poly(ethylene terephthalate) (PET) nanocomposites were prepared by the melt mixing method and the content of the EG was fixed as 2 wt%. The effect of multi-walled carbon nanotubes (MWCNTs) as a co-carbon filler on the electrical and mechanical properties of the EG/PET was investigated. The results showed that the electrical and mechanical properties of the EG/PET were significantly increased with the addition of MWCNTs, showing an improvement over those of PET prepared with EG alone. This was most likely caused by the interconnections in the MWCNTs between the EG layers in the PET matrix. It was found that the addition of the MWCNTs into EG/PET led to dense conductive networks for easy electron transfers, indicating a bridge effect of the MWCNTs.

• Korean Journal of Materials Research
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• v.18 no.2
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• pp.65-68
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• 2008

The present work was performed to investigate the effect of coiling temperature on the annealed texture in Cu/Nb-added ultra-low-carbon steels. The ultra-low-carbon steels were coiled at 650 and $720^{\circ}C$, respectively. The result showed that the Cu-added ultra-low-carbon steel at a low coiling temperature produced a desirable annealed texture related to good formability. On the other hand, Nb-added ultra-low-carbon steel at a high coiling temperature also produced a desirable texture. This is attributed to the effect of Nb, which retards recrystallization during the coiling process.

• The Journal of Korean Physical Therapy
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• v.18 no.6
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• pp.13-21
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• 2006

Purpose: To provide the basic method for physical therapy to contribute to early stage treatment of a burned patients. We investigated whether or not carbon arc lamp treatment and low level laser one among various laser treatments have the effect of reducing Cytokine, and to elucidate the effect of carbon arc lamp treatment and laser one. Methods: The 6-week old BALB/c types of 92 mice were used for the experimental test, and they were burned with $100^{\circ}C$ water, they were divided into 4 groups in accordance with the method of treatment respectively. And the blood and the tissue from the subject of each group were extracted and analyzed each time after they were cured for 3, 6, 9 days. For the analysis of the results, SPSS statistical program was used in this study. Results: The quantity of $TNF-{\alpha}$ and $IL-1{\beta}$ within the blood of a burned mouse increased more than that of a normal mouse(p<0.01). In only a burned mouse, carbon arc lamp treatment gave the effect on the decrease of $TNF-{\alpha}$ thickness the 6th day to the 9th day(p<0.01). $IL-1{\beta}$ quantity was more decreased than that of control group around the 6th day. In comparison with only a control group, low level laser treatment has more significant effect in decreasing the quantity of $TNF-{\alpha}$ a and $IL-1{\beta}$ than the two different methods(p<0.01). In case that the two treatment methods, carbon arc lamp treatment and low level laser, were executed together, there was the effect of decreasing $TNF-{\alpha}$ until the 6th day(p<0.01). Conclusion: Both low level laser treatment and carbon arc lamp one would be able to have an effect on the inflammation inhibition of burned patients and tissues reproduction. However, it must be also considered for the two treatments to be done at the same time.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.12
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• pp.113-118
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• 2010

For a present study, woven type carbon fibers were surface-modified by oxygen plasma to improve adhesive strength between carbon fibers and epoxy. The change of hydrophilic properties by the plasma modification was investigated through the contact angle measurement and the calculation of surface energy of carbon fiber due to the oxygen plasma modification. FESEM and XPS analyses were performed to study the chemical and physical changes on the surface of carbon fibers due to the oxygen plasma modification. Pin-on-disk wear tests were conducted under dry condition using unmodified and plasma-modified carbon/epoxy composites to investigate the effect of plasma modification on the wear behavior of woven type carbon/epoxy composites. The results showed that the friction coefficient and the wear rate of plasma-modified carbon/epoxy composites were lower than those of unmodified carbon/epoxy composites, respectively. XPS analysis showed that new functional group of a carbonyl type was created on the carbon fibers by the $O_2$ plasma treatment, which enhanced adhesive strength between carbon fibers and epoxy, leading to improve wear properties

• Korean Journal of Materials Research
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• v.19 no.12
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• pp.644-648
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• 2009

Temperature dependency of resistivity of the carbon black-polyethylene composites below and above percolation threshold is studied based on the electrical conduction mechanism. Temperature coefficient of resistance of the composites below percolation threshold changed from minus to plus, increasing volume fraction of carbon black; this trend decreased with increasing volume fraction of carbon black. The temperature dependence of resistivity of the composites below percolation threshold can be explained with a tunneling conduction model by incorporating the effect of thermal expansion of the composites into a tunneling gap. Temperature coefficient of resistance of the composites above percolation threshold was positive and its absolute value increased with increasing volume fraction of carbon black. By assuming that the electrical conduction through percolating paths is a thermally activated process and by incorporating the effect of thermal expansion into the volume fraction of carbon black, the temperature dependency of the resistivity above percolation threshold has been well explained without violating the universal law of conductivity. The apparent activation energy is estimated to be 0.14 eV.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.6_3
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• pp.1165-1171
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• 2022

In this paper, the results of an experimental study were presented by measuring and comparing the flexural strength and deformation on the carbon fiber sheet strength reinforced concrete beam considering end anchorage effect. For this purpose, total six specimens of 100×100×600mm size were prepared and tested according to the KDS 14 20 20. The specimens were categorized in three cases as reference beams without strengthening, beams carbon fiber strengthened but not anchored and beams carbon fiber strengthened also anchored. Experimental results showed that the end anchorage contributed to increase the flexural strength about 42% greater than that of carbon fiber sheets alone, and the number and width of cracks were relatively increased. The results support a considerable effects of end anchorage for carbon fiber strengthened reinforced concrete beams in enhancing the flexural performance. Further studies are needed in durability and long term behavior of carbon fiber sheet strengthened reinforced concrete beams.

• Journal of Korea Foundry Society
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• v.3 no.3
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• pp.159-166
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• 1983

In order to develope domestic carburizers, the experiment was carried out by applying crystallization heat treatment to domestic anthracites and also to foreign products to compare with domestic anthracites.The present work was mainly concerned with the effect of their degree of crystallization of carbon-bearing materials on carbon pick-up in molten iron.Those effects were evaluated by the measurement of density, chemical composition, specific electric resistivity, and X-ray intensity of carbon-bearing materials. Experimental results thus obtained were summurized as follows. 1. The degree of crystallization of domestic anthracites and foreign products was increased with increasing heat treatment temperature. 2. The more degree of crystallization, the shorter the dissolving time of domestic anthracites in molten iron was obtained, while that of foreign products was remained constant. 3. As the degree of crystallization of domestic anthracites and foreign products was increased, the carbon content as well as carbon recovery in molten iron was increased.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.133.1-133.1
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• 2010

In this work, carbon black(CBs)-embed multi-walled carbon nanotubes (MWNTs) as conductive fillers for activated carbon(ACs)-based electrodes for supercapacitor were prepared by chemical reduction of oxidized MWNTs and CBs. The effect of CBs-MWNT composites on electrochemical performances of ACs-based electrodes were investigated as a function of CB-MWNT ratio. It was found that CBs-MWNTs composites were formed by the reduction reaction of the functional groups of oxidized MWNTs and CBs. It was resulted in the conjugation of CBs onto the MWNT having high surface area and aspect ratio, leading to the enhanced electrical properties of MWNTs. The electrochemical performances, such as current density, charge-discharge, and specific capacitance of the ACs/CBs-MWNT electrodes were higher than that of ACs/MWNTs and conventional ACs/CB electrodes, which was attributed to the synergistic effect of CBs-MWNTs as a conductive filler.

• Journal of Korean Society of Water and Wastewater
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• v.21 no.3
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• pp.323-329
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• 2007

There is no certain definition about advanced drinking water treatment but it is generally known as activated carbon process, membrane process or ozone process which can remove non-conventional pollutants such as taste and odor compounds, and micro-pollutants. There are more than 20 processes related to activated carbon as adsorber or biological activated carbon in Korea. The saturated carbon by pollutants can be reused by reactivation. However, the effect of reactivation on activated carbon is not well-understood in terms of changing physical properties of carbon to adsorption capacity of natural organic matter (NOM). In this study, the effects of reactivation on physical properties of activated carbon were investigated by isotherm and breakthrough of NOM. Ash content was increased from 8% to 13.3%. Iodine number is commonly used as an indicator for performance of reactivation. The iodine number was decreased about 20% after reactivating twice. The degree of reactivation can be evaluated by not only iodine number but also apparent density.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.95.1-95.1
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• 2011

In this work, graphene was prepared by modified Hummers method and prepared graphene was applied to electrode materials for supercapacitor. In addition, to enhance the electrochemical performance of graphene, carbon black was deposited onto graphene via chemical reduction. The effect of the carbon black content incorporated on the electrochemical properties of the graphene-based electrodes was investigated. It was found that nano-scaled carbon black aggregates were deposited and dispersed onto the graphene by the chemical reduction of acid treated carbon black and graphite oxide. From the cyclic voltammograms, carbon black-deposited graphene (CB-GR) showed improved electrochemical performance, i.e., current density, quicker response, and better specific capacitance than that of pristine graphene. This indicates that the carbon black deposited onto graphene served as an conductive materials between graphene layers, leading to reducing the contact resistance of graphene and resulted in the increase of the charge transfer between graphene layers by bridge effect.