• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.3
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• pp.169-175
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• 2008

A fine carbon fibers dispersion model is implemented to calculate the scattering range and ground level concentration of carbon fibers emitted at certain altitudes of atmospheric boundary layer. This carbon fibers dispersion model was composed by coupling a commonly used atmospheric dispersion model and an atmospheric boundary layer model. The atmospheric boundary layer model, applying the Monin-Obukov Similarity Rule obtained from measurement input data at ground level, was used to create the atmospheric boundary layer structure. In the atmospheric dispersion model, the Lagrangian Particle Model and the Markov Process were applied to calculate the trajectory of scattered carbon fibers relative to gravity and aerodynamic force, as well as carbon fibers specification.

• Textile Coloration and Finishing
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• v.22 no.1
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• pp.43-50
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• 2010

The thermal treatment for carbon nanotube was applied to remove the water, metal catalyst and other impurities in carbon nanotube. The surface of carbon nanotube was changed into open structure with acid treatment by mixed solution of $HNO_3$ and $H_2SO_4$. The dispersion property of the functionalized and modified carbon nanotube was assessed with naked eyes by dispersing it in DMF. Carbon nanotube mixd polyurethane film was made to estimate the dispersion property by reflectance of the film with UV-Vis spectrometer. Also the internal structure of carbon nanotube was observed with SEM and TEM and thermal pyrolysis property of the carbon nanotube was measured by TGA and DSC. The surface modification of carbon nanotube by thermal and acid treatments improved the dispersion property of carbon nanotube/polyurethane mixed materials.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.55-58
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• 2003

This paper presents a study on the permittivities of the carbon nano fiber/epoxy composite at microwave frequency. The permittivities of composite materials depend on the concentrations and the dispersion methods of the carbon nano fibers. The experimental values of complex permittivities were obtained for the specimen made by dispersion method using ethyl alcohol as dispersion media and compared with the results by simple mechanical mixing method.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.151-154
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• 2004

Despite of the excellent properties of carbon nanofiber, The properties of carbon nanofiber filled polymer composites were not increased largely. The reason is that it is still difficult to ensure the uniform dispersion of carbon nanofiber in a polymer matrix. In this study, For improvement properties of carbon nanofiber filled epoxy composites, the effect of dispersion was investigated. The compounds were prepared by two methods, solution blending and mechanical mixing. Mixing of solution blending method was used using ultrasonic. Dispersion of carbon nanofiber was observed by optical microscope and scanning electron microscope (SEM). UV adsorption and turbidity measured by UV spectrometer was used for the comparison of dispersion of carbon nanofiber.

• Journal of the Korean Society of Propulsion Engineers
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• v.13 no.3
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• pp.34-40
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• 2009

For the preparation of carbon-slurry fuel, the effects of process parameters on the carbon dispersion stability in the liquid fuel have been investigated. The dispersion stability of carbon-slurry fuels could be monitored by measurements of particle size and carbon contents in the different positions, and observation of dispersion states after centrifuging. Through the application of various additives, it was found that NB463S84 based on polyolefin succinimde showed the best dispersion and longest stability life of carbon-slurry fuel. Also, PIBSI (polyisobutenyl succimide) with the similar functional groups to NB463S84 was effectively synthesized and same dispersion stability was verified by application to carbon-slurry fuel. Finally, the possibility of practical use of carbon-slurry fuels was confirmed by application of the mixing conditions obtained from g scale to kg scale preparation.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.529-529
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• 2012

Dispersion of carbon nanotubes in biocompatible media are of particular interest for diverse biomedical and nanomedicine applications. Various biomolecules and biopolymers such as DNA, proteins, poly L-lysine, starch, gelatin, steroid biosurfactants, and chitosan have shown capability for the effective dispersion of carbon nanotubes in water. Chitosan has demonstrated capacity for effective dispersion of single-walled carbon nanotubes (SWCNTs) in acidic medium and it also showed tendency to preferentially disperse smaller diameter nanotubes. Chemical functionalizations of chitosan enable its solubility in neutral pH water by reducing the intra and inter molecular hydrogen bonding. Herein, we present a neutral pH water soluble chitosan derivative, chitosan-hydroxyphenyl acetamide (CHPA), obtained by functionalizing the amino groups of chitosan with 4-hydroxyphenyl acetic acid, as an efficient biocompatible dispersant for debundling and solubilization of SWNTs in neutral aqueous solutions. Various process conditions for individual dispersion of SWCNTs are analyzed based on optical absorption and Raman spectroscopy.

• Applied Chemistry for Engineering
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• v.18 no.1
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• pp.64-70
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• 2007

Preparation and characterization of carbon-slurry fuel with high dispersion have been carried out. Carbon-slurry fuel was obtained by mixing Jet A-1 liquid fuel with appropriate carbon powders and additives. Dispersion of carbon in Jet A-1 was affected by various factors such as mixing temperature, characteristics of carbon powders, and type and amount of additives. Among these factors, the stability of the slurry fuel was most dependent on the type of additive. A variety of additives such as anionic, cationic, and nonionic additives was tested for the dispersion of carbon in Jet A-1. It was found that anionic additives based on sodium salts showed the highest dispersion of carbon-slurry fuels. The degree of dispersion could be monitored by measuring the luminosity.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08a
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• pp.778-781
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• 2007

The dispersion of carbon nanotubes in composite and their field emission superiority have been discussed. Four synthesis methods have been studied. The CNT-composite, synthesized by the combination of the chemical and mechanical dispersion routes shows superior dispersion as well as field emission characteristics as compared to other syntheses methods.

• Carbon letters
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• v.14 no.4
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• pp.218-227
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• 2013

A supercritical carbon dioxide (SCC) process of dispersion of multi-walled carbon nanotubes (MWCNTs) into epoxy resin has been developed to achieve MWCNT/epoxy composites (CECs) with improved mechanical, thermal, and electrical properties. The synthesis of CECs has been executed at a MWCNT (phr) concentration ranging from 0.1 to 0.3 into epoxy resin (0.1 mol) at 1800 psi, $90^{\circ}C$, and 1500 rpm over 1 h followed by curing of the MWCNT/epoxy formulations with triethylene tetramine (15 phr). The effect of SCC treatment on the qualitative dispersion of MWCNTs at various concentrations into the epoxy has been investigated through spectra analyses and microscopy. The developed SCC assisted process provides a good dispersion of MWCNTs into the epoxy up to a MWCNT concentration of 0.2. The effects of SCC assisted dispersion at various concentrations of MWCNTs on modification of mechanical, thermal, dynamic mechanical thermal, and tribological properties and the electrical conductivity of CECs have been investigated.

• Journal of the Korea Concrete Institute
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• v.29 no.3
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• pp.283-290
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• 2017

Various types of fibers are utilized in cementitious materials in order to improve their performances. Here, the extent of fiber dispersion is of key importance regardless of the purpose of using fiber. In this study, activated carbon fiber dispersion in mortar samples was evaluated using electrical resistivity method. In particular, the extent of fiber dispersion was compared per mixing methods and surface treatments. The results suggest that the surface resistivity method is capable of evaluating dispersion of activated carbon fiber and that ultrasound dispersion method is superior to mortar mixer and hand mixer method. The use of superplasticizer improved dispersion but acid treatment was not effective.