• Journal of the Korean Electrochemical Society
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• v.4 no.3
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• pp.104-108
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• 2001

Naphthalene derived mesophase pitch WP) was spun into short fibers by using melt-blown technology. The pitch fibers oxidative stabilization were carried out heating rates of $2^{\circ}C/min,\;5^{\circ}C/min\;and\; 10^{\circ}/min$. The heating rate was a key factor to maximate the capacity of the Li-ion secondary battery through controlling the morphology of the graphitized fiber. The diameters of the melt-blown fibers prepared were in the range of $4{\mu}m\~16{\mu}m$ with functions of air jet speed, air temperature and the temperature of the nozzle. The graphitized fibers of $10{\mu}m$ diameters showed various morphological structure with heating rate of the stabilization. Radial, radial-random and skin-core cross-sectional structure of the fibers were observed at the respective heating rate of $2^{\circ}C/min\;5^{\circ}C/min\;and\;10^{\circ}C/min$. Most crystalline structure of graphite was obtained from the fiber stabilized at heating rate of $10^{\circ}C/min$ exhibiting the best anode performance with 400 mAh/g of capacitance and $96.8\%$ of charge/discharge efficiency.

• Journal of the Korean Vacuum Society
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• v.19 no.5
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• pp.377-384
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• 2010

Many routes have been developed for the synthesis of signle-walled carbon nanotubes (SWCNTs). We spun fibers of SWCNTs directly from vertical furnace using a liquid source of carbon and an iron-contained molecule. The solution was prepared by ethanol as a carbon source, in which ferrocene as a catalyst, thiophene were dissolved. It was then injected from the top of the furnace into hot zone with hydrogen as a carrier gas. We successfully synthesized high-quality SWCNTs by adjusting the various experimental conditions, such as concentration of ferrocene, solution injection rate, concentration of thiophene, and hydrogen flow rate. Measurement of Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy were carried out to find the optimized conditions. The synthesized SWCNTs (1.16~1.64 nm) appeared a bundle structure and well-aligned parallel to the direction of furnace. These results also provide an simple way for high-quality SWCNTs mass production and fabricating direct spining SWCNTs fiber. It will allow one-step production of SWCNTs fiber with potentially excellent properties and wide-range applications.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.9
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• pp.1268-1273
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• 2011

The present study was conducted to determine a feasible method of protein concentrate extraction from rice bran (RBPC) and its effect as a substitution for skim milk in early weaning pig diets. An investigation to extract protein concentrate from full fat rice bran was undertaken to determine the best ratio of water and rice bran, the amount of NaOH and a HCl solvent to use in a simple paddle-type mixer with modified spinning to produce RBPC. The results stated that the best ratio for water mixing in the RBPC extraction process was 1:5 with 20 g NaOH and 30 min in a paddle-type mixer at 300 rpm. A mix of 250 ml 0.2 N HCl was optimum for neutralization and protein precipitation. After the fluid was spun out with a washing machine, the sediment was left for 12-14 hours to complete the filtration. One kilogram of rice bran could produce an average of 324.5 gram RBPC and it contained 3.40% ash, 496.48 kcal of GE/100 gram, 1.94% crude fiber, 28.20% ether extract, 7.64% moisture and 16.66% crude protein, respectively. A total of 45 crossbred piglets, weaned at 3 weeks of age were allotted into control diet (A) and dietary treatments formulated with a four different rates of RBPC substitution for skim milk at a percentage of 25 (B), 50 (C), 77 (D) and 100 (E) respectively, in a randomized complete block (RCB) design. All piglets had free access to feed and water until 8 week of age when the experiment ended. Feed intake, average daily gain, growth rate and feed efficiency were not affected by dietary treatments. Blood test parameters after completion of the growth trial indicated normal health. Even though the mean of cell hemoglobin concentration was significantly different between treatments (p<0.05) it was still within the normal range. The cost difference for BW gain of 100% RBPC substituted for skim milk in the weaning diet was approximately 35% lower than that of the control and the relative cost of production was 96.67, 92.85, 70.75 and 64.48% lower for the replacement of 25, 50, 75 and 100% of skim milk respectively. These results implied that this technology is feasible for use by small scale farmers to improve their self-reliance.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.89-89
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• 2012

선행 연구에서는 m-Aramid와 p-Aramid의 Ring 방적사/Core 방적사 조건에 따른 방적사 물성에 대해서 연구하였는데, Ring 방적사의 혼용율, 스핀들 속도에 따른 물성 변화, Core 방적사의 공정특성에 따른 방적성, 피복성에 대해 연구를 하였다. 그 결과 Ring 방적사의 경우 m-Aramid의 혼용율이 증가할수록 사 강도는 증가하는 경향을 확인할 수 있었고, 스핀들 속도가 증가함에 따라서 불균제도 및 사결점이 다소 증가하였다. Core 방적사의 경우 Core에 p-Aramid를 사용했을 때 방적성과 피복성은 양호 하였지만, 강한 p-Aramid에 의해 톱 롤러코트의 마모가 되는 경향을 볼 수 있었다. 본 연구에서는 Ring 방적사/Core 방적사에 대해 좀더 구체적인 제조공정조건에 의한 물성 변화를 알아보았고, 좀더 다양한 섬유소재를 적용해서 제조하였다. Ring 방적사의 경우 p-Aramid 혼용율에 따른 실험을 하였는데, m-Aramid에 대한 p-Aramid의 혼용율을 0%, 5%, 10%, 20% 로 하여 Ne30을 제조하였으며, Core 방적사는 Core를 p-Aramid 200D로 하고 Sheath를 Cotton으로 하여 Core 공급속도비 (1.06, 1.10, 1.14), 연계수(T/M, 3.8, 4.0, 4.2), Sheath/Core 혼섬율(70/30, 60/40, 50/50)에 따라 제조하였다. 추가로 Core 방적사는 Sheath에 Cotton 대신 FR-Rayon과 선염 Cotton을 사용하여 각각 Sheath/Core 혼섬율 70/30의 비율로 방적사를 제조하여 다양한 소재에 따른 방적사의 물성을 측정하였다. 제조된 시험 원사들의 측정 물성은 번수(Ne), 균제도(U%), 사결점(IPI), 강력(cN), 신도(%), 비강도(cN/Tex) 등이며, 편직을 통해 편성물의 외관을 확인하였다. Ring 방적사의 경우 p-Aramid의 혼용율이 증가할수록 강도는 완만하게 증가한 반면, 신도는 급격하게 감소하였다. Cotton Core 방적사의 경우는 공급속도비가 높아질수록 균제도가 높아지는 것을 볼수 있었고, Core 공급속도비가 높아질수록 외관상 피복도는 높아진 것을 볼 수 있었다. 이렇게 연구된 Aramid 소재를 이용한 방적사 제조 공정조건변화에 따른 물성 및 피복도 결과는 기존 방적업체에서 Aramid를 이용한 방적사 제조시에 공정조건을 확보하는데 도움이 될 것이라 생각되며, 방적사 시제품 생산시에 발생할 수 있는 시행착오를 줄임으로써 시제품 제조를 위한 생산비용의 Loss를 절감할 수 있을 것으로 예상된다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.30 no.6
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• pp.226-231
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• 2020

Polyvinyl pyrrolidone nanofibers including nickel, zinc, and iron precursors were fabricated via the electrospinning method. To convert as-spun nanofibers to Ni0.5Zn0.5Fe2O4 oxide nanof ibers which is capable of shielding an electromagnetic wave, heat treatment conditions were optimized. To obtain the heat treatment condition that can exclude amorphous carbon black and secondary crystal phase, samples were taken at each temperature while the calcination process and analyzed. According to the X-ray diffraction (XRD) analysis, the Ni0.5Zn0.5Fe2O4 crystal phase started to appear from 300℃, but it was confirmed through energy dispersive spectroscopy (EDS) analysis that heat treatment of 500℃ or more was required to remove most of the carbon black. When the calcination temperature exceeds 650℃, crystal nuclei starts to grow and the fiber surface condition becomes rough, so it was confirmed that the heat treatment conditions should be selectively determined according to the application field.