• Title/Summary/Keyword: Fiber Formation

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Necking Formation in Drawing Processes of Fibers (섬유의 연신 공정에서의 네킹 형성)

  • 윤형섭;정관수;윤재륜
    • Proceedings of the Korean Fiber Society Conference
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    • 2001.10a
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    • pp.131-134
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    • 2001
  • 합성섬유의 방사공정 중 하나인 연신 공정은 섬유의 성질을 향상시키기 위해 고화된 상태의 섬유를 신장하는 공정이다. 연신할 때 변형이 국부적으로 일어나는 네킹이 일반적으로 관찰되는데, 이 현상은 방사 공정 후에 일어나는, 합성섬유의 역학적 성질과 미세구조에 큰 영향을 미친다[1]. 본 논문에서는 네킹을 분자 구조의 변화에 대한고려 없이 거시적인 관점에서 해석하였다. (중략)

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Properties of Silicon Carbide-Carbon Fiber Composites Prepared by Infiltrating Porous Carbon Fiber Composites with Liquid Silicon

  • Lee, Jae-Chun;Park, Min-Jin;Shin, Kyung-Sook;Lee, Jun-Seok;Kim, Byung-Gyun
    • The Korean Journal of Ceramics
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    • v.3 no.4
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    • pp.229-234
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    • 1997
  • Silicon carbide-carbon fiber composites have been prepared by partially Infiltrating porous carbon fiber composites with liquid silicon at a reaction temperature of $1670^{\circ}C$. Reaction between molten silicon and the fiber preform yielded silicon carbide-carbon fiber composites composed of aggregates of loosely bonded SiC crystallites of about 10$\mu\textrm{m}$ in size and preserved the appearance of a fiber. In addition, the SiC/C fiber composites had carbon fibers coated with a dense layer consisted of SiC particles of sizes smaller than 1$\mu\textrm{m}$. The physical and mechanical properties of SiC/C fiber composites were discussed in terms of infiltrated pore volume fraction of carbon preform occupied by liquid silicon at the beginning of reaction. Lower bending strength of the SiC/C fiber composites which had a heterogeneous structure in nature, was attributed to the disruption of geometric configuration of the original carbon fiber preform and the formation of the fibrous aggregates of the loosely bonded coarse SiC particles produced by solution-precipitation mechanism.

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Fabrication and Characteristics of Chitosan Non-woven Fabric developed using only water as plasticizer

  • Lee, Shin-Hee;Hsieh, You-Lo
    • Fashion & Textile Research Journal
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    • v.16 no.2
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    • pp.319-325
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    • 2014
  • This article describes a method for producing chitosan non-woven fabrics by just hot pressing without the use of a binder. A study has been made of the wet spinning of chitosan fiber. The fibers were rinsed thoroughly in running water and chopped wet into staples of with a length of approximately 5-10 mm. The chopped chitosan staples were dispersed uniformly in water and fabricated using a non-woven making machine. This study examined the formation and the characteristics of chitosan non-woven fabrics manufactured by hot pressing without the use of a binder. The effects of the non-woven fabrication conditions on the thermal, morphological, structural, and physical properties of chitosan non-woven fabric with and without water as a plasticizer were studied. The temperature of the exothermic peak, decomposition of chitosan fibers increased with increasing heating rate. Water in the chitosan fiber effectively plasticized the chitosan fiber. The thermal bonded structure of the wet chitosan fiber with water as a plasticizer was clearly found in many parts of the non-woven fabric at a fabrication temperature of $200^{\circ}C$. The intensity and profile of the (100) plane($2{\theta}=10.2^{\circ}$) and (040) plane($2{\theta}=20.9^{\circ}$) in the chitosan non-woven fabric decreases and became smooth in the non-woven fabric formation by melting.

Development of fiber reinforced self-compacting concrete (FRSCC): Towards an efficient utilization of quaternary composite binders and fibers

  • Fediuk, Roman;Mosaberpanah, Mohammad A.;Lesovik, Valery
    • Advances in concrete construction
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    • v.9 no.4
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    • pp.387-395
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    • 2020
  • This study has been carried out in two-phases to develop Fiber Reinforced Self-Compacting Concrete (FRSCC) performance. In the first phase, the composition of the quaternary composite binder compromised CEM I 42.5N (58-70%), Rice Husk Ash (25-37%), quartz sand (2.5-7.5%) and limestone crushing waste (2.5-7.5%) were optimized. And in the second phase, the effect of two fiber types (steel brass-plated and basalt) was investigated on the SCC optimized with the optimum CB as disperse reinforcement at 6 different ratios of 1, 1.2, 1.4, 1.6, 1.8, and 2.0% by weight of mix for each type. In this study, the theoretical principles of the synthesis of self-compacting dispersion-reinforced concrete have been developed which consists of optimizing structure-formation processes through the use of a mineral modifier, together with ground crushed cement in a vario-planetary mill to a specific surface area of 550 m2 / kg. The amorphous silica in the modifier composition intensifies the binding of calcium hydroxide formed during the hydration of C3S, helps reduce the basicity of the cement-composite, while reducing the growth of portlandite crystals. Limestone particles contribute to the formation of calcium hydrocarbonate and, together with fine ground quartz sand; act as microfiller, clogging the pores of the cement. Furthermore, the results revealed that the effect of fiber addition improves the mechanical properties of FRSCC. It was found that the steel fiber performed better than basalt fiber on tensile strength and modulus of elasticity; however, both fibers have the same performance on the first crack strength and sample destruction of FRSCC. It also illustrates that there will be an optimum percentage of fiber addition.

Effect of Humidity on the Electrospinning of Chitosan Solution (키토산 용액의 전기방사에 있어 습도의 영향)

  • Lee, Jin-Ah;Joo, Chang-Whan
    • Proceedings of the Korean Fiber Society Conference
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    • 2003.10b
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    • pp.273-274
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    • 2003
  • Chitin and chitosan have a wide range of application on the environmental and biomedical engineering by their biocompatibility, biodegradability, non-toxicity and adsorption property, etc. The efforts of manufacturing chitosan fibers are continuously maintained until now$\^$l.2)/. Electrospinning is new method to produce the nano-sized fibers for medical uses. Recently, formation of chitosan fiber using electrospinning is studied by many textile researchers. (omitted)

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Surface Modification of Glass Fiber by Fluorination and Formation of Glass/PTFE Composites (Fluorination에 의한 유리섬유의 표면개질과 Glass/PTFE 복합재료의 형성)

  • 이승구;천성국;유근실;김동철;주창환
    • Proceedings of the Korean Fiber Society Conference
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    • 2001.10a
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    • pp.413-416
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    • 2001
  • 여러 가지 기능성 섬유나 섬유복합재료에서는 가공성이나 계면접착성 향상 및 응용성을 높이기 위하여 섬유 표면을 개질하여 사용하는 경우가 많다. 지금까지 연구된 섬유의 표면개질 방법으로는 화학적 처리방법, 광화학적 방법, 플라즈마 처리법 등이 개발되어 있다. 화학적 방법은 장비가 간단한 장점이 있지만 사용 약품이 대부분 강한 독성을 지니고 있어서 작업 및 환경오염에 큰 문제점이 있고, 광화학적 방법은 radiation 에너지가 커야 하고 광에너지의 차폐 문제가 있다. (중략)

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발육기 하악골에 있어 골기질의 조직화학적 관찰

  • Park, Doo-Hwan
    • The Journal of the Korean dental association
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    • v.12 no.5
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    • pp.347-349
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    • 1974
  • The demonstrations of collagenous fiber in mandibul ar bone formation were analized histochemically, using Carson's Mallary-Heidenhein stain, McManus' PAS reaction and H-E stain The stain ablity of osteoid increased with formation of bone tissue. In the surrounding areas of osteoblast and osteocyte were showed slight activity.

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