• 한국구조물진단유지관리공학회 논문집
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• 제23권4호
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• pp.23-30
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• 2019

섬유보강 시멘트계 복합재료 (이하 FRCC)는 균열 폭의 제어 등의 역학적인 효과뿐 아니라 철근방식에도 효과가 있는 것이 기존의 문헌으로부터 확인되고 있다. 본 연구에서는 아연섬유를 포함한 각종 금속섬유를 이용하여 철근의 방식효과를 부식 촉진 실험에 의해 검토했다. 더욱이 방식효과에 큰 영향을 미치는 염분침투, 희생양극 효과, 전기회로 형성에 주목하여, 각각의 요인에 있어서 검토를 실시했다. 그 결과, 금속섬유를 혼입한 FRCC의 방식효과를 확인할 수 있었으며, 특히 희생 양극효과가 높은 아연섬유의 경우, 염분침투 억제 효과가 뛰어나 내부식 성능이 향상되는 것을 확인할 수 있었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.908-912
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• 1996

FRMLs consist of thin sheets of high strength metal, which are laminated using a structural adhesive and high strength fibers. ARALL(Aramid-fiber Reinforced Aluminum alloy Laminates) of FRMLs is a new class of hybrid material. HERALL(Heracron Reinforced Aluminum Laminate) i.e. domestic ARALL is made of homemade aramid fibers, adhesives and adhesive technique. Domestic aramid fiber is Heracron manufactured by KOLON and domestic adhesive is epoxy resin manufactured by Han Kuk Fiber. In this study, Fatigue crack propagation behavior was examined in a 2024-T3 aluminum alloy/aramid-fiber epoxy 3/2 laminated composites, HERALL and ARAL $L^{ⓡ}$-2 LAMINATE comparing with 2024-T3 aluminum alloy. The extrinsic toughening mechanisms in HERALL and ARALL were examined, the crack bridging behavior of fibers was analyzed by new algorithm, which measures crack bridging stress, and the crack bridging zone length was measured.

• 센서학회지
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• 제20권2호
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• pp.82-89
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• 2011

Ruthenium(Ru)-doped $TiO_2$ nanofibers were prepared using electrospun Ru-$TiO_2$/poly(vinyl acetate) (PVAc) fibers and subsequent annealing for 1 h at temperatures in the range of $500^{\circ}C$ to $1000^{\circ}C$ in air. The properties of the Ru-$TiO_2$ fibers were characterized as a function of the Ru content and calcination temperature using X-ray diffraction, thermal gravimetry with differential scanning calorimetry, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and viscometer, pycnometer and dynamic tensiometer measurements. Although the diameter of the fiber decreased slightly with increasing calcination temperature, no dramatic changes were observed with respect to the ruthenium content. The XRD and FT-IR results revealed that anatase phase and ruthenium metal began to be formed after calcination at temperatures above $500^{\circ}C$. Anatase and rutile phases and ruthenium metal coexisted in the fibers calcined above $600^{\circ}C$. No anatase phase was detected in the fibers containing ruthenium when they were calcined at $1000^{\circ}C$. The morphology of the fibers changed from smooth and uniform to porous with increasing temperature. The experimental results suggest that the calcination temperature and Ru content were influential in determining the morphology and structure of the fibers.

• 한국염색가공학회지
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• 제8권6호
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• pp.40-46
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• 1996

In order to investigate a practical application of fibrous absorbents to transition metals such as copper, nickel, cobalt, chrome, and iron, amidoximated fiber as a particular class of solid chelate agents were prepared from acrylic fibers treatment with hydroxylamine. The adsorption mechanisms of metal ions onto amidoximated acrylic fibers and their complexes were studied. Amidoximation of acrylic fiber with hydroxylamine is found to be first-order reaction, followed by the disappearance of infrared adsorption peaks due to nitrile groups of acrylic fibers. The uptake of metal ions onto amidoximated acrylic fiber is increased with temperature raising and the adsorption is also depended on pH of the soiutions. About 70% of metal ions can be recovered from aqueous solutions of Ni(II), Co(II), Cr(III), and Fe(II) on the concentration below 5x 10$^$^{-4}$ in the range of pH 2.1~10.0. Transition metals are adsorbed to form complex with amidoxime group by the ligand sites such as C=N, NH, NO, NHOH.OH.

• Carbon letters
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• 제2권1호
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• pp.15-21
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• 2001

In this work, activated carbon fibers (ACFs) were plated with copper metal using electroless plating method and the effects of surface properties and pore structures on chromium adsorption properties were investigated. Surface properties of ACFs have been characterized using pH and acid/base values. BET data with $N_2$ adsorption were used to obtain the structural parameters of ACFs. The electroless copper plating did significantly lead to a decrease in the surface acidity or to an increase in the surface basicity of ACFs. However, all of the samples possessed a well-developed micropore. The adsorption capacity of Cr(III) for the electroless Cu-plated ACFs was higher than that of the as-received, whereas the adsorption capacity of Cr(VI) for the former was lower than that of the latter. The adsorption rate constants ($K_1$, $K_2$, and $K_3$) were also evaluated from chromium adsorption isotherms. It was found that $K_1$ constant for Cr(III) adsorption depended largely on surface basicity. The increase of Cr(III) adsorption and the decrease of Cr(VI) adsorption were attributed to the formation of metal oxides on ACFs, resulting in increasing the surface basicity.

• 한국의류학회지
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• 제13권2호
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• pp.128-136
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• 1989

In order to investigate a practical application of fibrous adsorbents to heavy metal ions, amidoxime fibers, as a particular class of solid chelate agents, were prepared by hydroxylamine treatment for acrylic fibers in a recipe of neutralization. Among the important problems from plant effluents are toxic concentrations of heavy metals such as copper. Accordingly, the properties of Cu (II) adsorption and its chelates were studied. The results obtained are as follows; The fibrous adsorbents have the property of increasing the swelling volumes by amidoximation. The adsorption of Cu (II) ion is characterized by an endothermic reaction, which is estimated as the plus values in the enthalpy change ($\delta$H=1.30 Kcal/mol. and 3.14 Kcal/mol.). The Cu (II) ions are adsorbed in the range of pH $3\~8$ and the maximum adsorptions are occurred about pH 8. Owing to the anions $(NO_3^-,\;Cl^-)$ of copper salts, amidoxime fibers form 1:1 and 2:1 (ligand: metal) chelating complexes with Cu (II). The nitrate anion chelates to amide I (NH) of amidoxime groups and the chlorine anion does to nitrosyl (NO). These effects relate to the crystallization of the complex and the thermal property.

• 폴리머
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• 제27권3호
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• pp.235-241
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• 2003

항균 활성이 없는 폴리아크릴로나이트릴계 활성 탄소 섬유에 항균 활성을 부여하기 위해 반응성이 큰 전이금속인 구리를 전해도금 방식으로 도입시켜, 활성 탄소 섬유의 항균 활성 및 기공 특성에 미치는 영향을 고찰해 보았다. 항균 활성 시험은 병원성 제균으로서 그람 양성균인 황색 포도상 구균 (Staphylococcus aureus)과 비병원성의 그람 음성균인 대장균 (Klebsiella pnemoniae)을 대상으로 그 효과를 측정하였으며, 활성 탄소 섬유의 기공 특성은 BET식, Boer의 t-plot, 그리고 H-K식을 이용하여 확인하였다. 도입되는 구리의 양이 많아질수록 활성 탄소 섬유의 비표면적, 총 기공 부피, 미세기공 부피 등이 감소되는 것이 관찰되었으며, 반면 항균 활성은 S. aureus 및 K. pnemoniae에서 증가되었다.

• 대한기계학회논문집
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• 제19권7호
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• pp.1619-1629
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• 1995

The Al/Al$_{2}$O$_{3}$ SiC and Al/Al$_{2}$O$_{3}$/C hybrid metal matrix composites (MMCs) were fabricated by squeeze infiltration method. Uniform distribution of reinforcements were found in the microstructure of metal matrix composites. Mechanical tests were carried out under various test conditions to clearly identify mechanical behavior of MMCs, and the wear mechanism of Al/Al$_{2}$O$_{3}$/(SiC or C) hybrid metal matrix composites were investigated. The tensile strength and hardness of hybrid composites was resulted in increasing compared with those of the unreinforced matrix alloy. Wear resistance was strongly dependent upon kinds of fiber, volume fraction and sliding speed. The wear resistance of metal matrix composites was remarkably improved by the addition of reinforcements. Especially, the wear resistance of the hybrid composites of carbon fibers was more effective than in the composites reinforced with alumina and SiC whiskers of reinforcements. This was due to the effect of carbon fiber on the solid lubrication. Wear mechanisms of hybrid composites were suggested from wear surface analyses. The major wear mechanism of hybrid composites was the abrasive wear at low to intermediate sliding speed, and the melting wear at intermediate to high sliding speed.

• 한국안전학회지
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• 제19권3호
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• pp.57-64
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• 2004

This is the study for the removal of a toxic heavy metal ions and the recycling of expanded polystyrene wastes. Thus expanded polystyrene wastes collected from the packing materials of TV or chemicals and dissolved by $80wt.\%$ solvent(N, N-Dimethylacrylamide), electrospun in DC 20kV by power supply. Generally, the electrospinning is a process of manufacture to the fibers of nanosize from polymer solution. Manufactured nanofiber mats by electrospinning were sulfonated by cone.-sulphuric acid with $Ag_2S_O_4$ catalysts for the exchange capacity of heavy metal ions and the properties of structure with sulfonated time investigated by FESEM(Feild Emission Scaning Electron Microscope). The ion exchange capacity of light metal$(Na^+)$, Cd(II) and Ni(II), and by a nanofiber mats were 1.94[mmo1/g-dry-mat), 1.72(mmol/g-dry-mat), 1.24(mmol/g-dry-mat), respectively., and water uptake content showed a similar trend with IEC. and The selectivity coefficients $K^M_H$ of Cd(II), Ni((II) ions showed 0.324, 0.228. respectively.

• 멤브레인
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• 제29권3호
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• pp.123-129
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• 2019

가속화되는 산업화로 인해 중금속 이온의 침출이 환경문제로 떠오르고 있다. 수질 정화를 위한 몇 가지 방법 중 기능성 고분자 섬유를 이용한 흡착은 효율적이며 경제적이라는 장점이 있다. 특히, 폴리아크릴로나이트릴(polyacrylonitrile, PAN)은 금속 이온을 흡착할 수 있는 작용기가 많아 관심을 끌고 있다. PAN은 쉽게 전기방사를 통해 고분자 나노 섬유화될 수 있으며 높은 표면적을 가질 수 있다. 본 총설에서 다룰 복합 PAN 섬유는 폐수 처리를 위한 또 다른 유형의 고분자이다.