• Textile Coloration and Finishing
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• v.15 no.2
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• pp.93-101
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• 2003

To acquire dyeing ability on aramid(Nomex) spun yarn in supercritical fluid dyeing, supercritical fluid dying(SFD) machine of 3L scale was designed. C. I. Disperse Red 60 and Red 360 were used in this work. It was possible to increase dyeing ability and to get level dyeing of fiber by attaching assistance devices(controlling device of supercritical fluid, nozzle, cover of carrier, etc.) to SFD machine. Physical properties(tensile strength, elongation, shrinkage) of Nomex spun yam treated by SFD were not changed. K/S values of dyed Nomex spun yam with Red 360 were higher than that with Red 60 and color fastness of dyed Nomex spun yam by SFD was similar to that by conventional dyeing method.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.95-98
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• 2003

In woven or knitted preforms for composites, the yams are often twisted for avoiding damage due to the contact with the textile machine elements. When the preforms of twisted yams are used in carbon/carbon composites, the thermal conductivity of the composites varies depending upon the degree of the yarn twist. This paper presents a thermal conductivity model of spun yarn composites. The thermal-electrical analogy and the averaging technique have been adopted in this analysis. The model prediction has been correlated with experimental results in order to confirm the model predictability. Parametric study has also been conducted to examine the effect of the yam twist on the thermal conductivity of spun yarn composites.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.90-93
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• 2005

A thermal model of carbon spun yarn and its composite is presented. Based on voxelization method, the unit cells of spun carbon yam and its composite are divided into a number of volume elements and the local material properties have been given to each element. By using Finite Difference Method, temperature distribution in the unit cell can be obtained. Effective thermal conductivity of unit cell is calculated using the temperature distribution and thermal conductivities of local elements.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.186-189
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• 2004

A thermal model of carbon spun yam is presented. The unit cell of spun carbon yam is divided into a number of volume elements and the local material properties have been given to each element. By using Finite Difference Method (FDM), temperature distribution in the unit cell can be obtained. Effective thermal conductivity of the spun carbon yam unit cell is calculated using the temperature distribution and thermal conductivities of local elements.

• Macromolecular Research
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• v.10 no.6
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• pp.318-324
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• 2002

In this paper we have extensively studied what and how processing parameters for quasi-carbonization influence the breaking strength and modulus of resulting quasi-carbon fabrics that are prepared from stabilized PAN fabrics with a spun yarn texture. Seven processing parameters have been considered as follows: applied tension, final heat-treatment temperature, heating rate, heating step, holding time, cooling rate, and purging gas purity. The results indicate that optimal uses of applied tension, final heat-treatment temperature, heating rate, and heating step during quasi-carbonization process are primarily important to increase the tensile properties of quasi-carbon fabrics and holding time, cooling rate, and purging gas purity are less importantly contributed.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.639-639
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• 2013

In this research we report the significant contribution of the as-spun multi-walled carbon nanotube (MWCNT) on the x-ray images formation using a low tube voltage x-ray source. The MWCNT, which was used for the fabrication of the spun CNT, was grown using a microwave plasma-enhanced chemical vapor deposition machine. Electrical-optics simulation software was utilized to determine the electron field emission trajectory of the triode-structure-as-spun CNT-based x-ray source. It was shown that a significant amount of converging electrons hit the target anode producing a clear x-ray image. These x-ray images where produced at a small amount of anode current of 0.67 mA at a tube voltage of 5 kV with the gate voltage of 0 V. Also, comparisons of the radiographs at various exposure times of the sample where analyzed with and without an x-ray dose filter. Results showed that spatially-resolved images were formed using the as-spun CNT at a low tube voltage with a $54-{\mu}m$ Al x-ray filter. This study can be used for low-voltage medical applications.