• Title/Summary/Keyword: Nano fiber

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High Temperature Gas Leak Behavior of Glass-Ceramic Fiber Composite Seals for SOFC Applications (SOFC용 유리-세라믹섬유 복합기밀재의 고온 기체누설 거동)

  • Lee, Jae-Chun;Kwon, Hyuk-Chon;Kwon, Young-Pil;Park, Sung;Jang, Jin-Sik;Lee, Jongho;Kim, Joosun;Lee, Hae-Won
    • Journal of the Korean Ceramic Society
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    • v.42 no.12 s.283
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    • pp.842-845
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    • 2005
  • Glass composites containing ceramic fiber have been developed for Solid Oxide Fuel Cell (SOFC) seals. Effect of glass type, loading pressure and thermal cycle the leak rates of composite seals was investigated. Seal performance of two commercial glasses was compared with that of $SiO_2BaO-B_2O_3$ glass synthesized in this work. The leak rate for seals made of pyrex(R) increases from $\~0.0005\;to\;\~0.004sccm/cm$ as the gas pressure increases from 10 to 50 kPa. The soda lime silicate glass seal shows the leak rate two times higher than the one made of pyrex(R) or $SiO_2BaO-B_2O_3$ glass. The viscosity of glass at the seal test temperature is presumed to affect the leak rate of the glass seal. As the applied loading pressure increases from 0.4 to 0.8 MPa at $750^{\circ}C$, the leak rate decreases from 0.038 to 0.024 sccm/cm for composite seals. It has been found that during 50 thermal cycles between $450^{\circ}C\;to\;700^{\circ}C$ leak rates remained almost constant, ranging from 0.025 to 0.03sccm/cm. The results showed an excellent thermal cycle stability as well as sealability of the glass matrix ceramic fiber composite seals.

Preparation of highly hydrophobic PVDF hollow fiber composite membrane with lotus leaf-like surface and its desalination properties

  • Li, Hongbin;Zi, Xingchen;Shi, Wenying;Qin, Longwei;Zhang, Haixia;Qin, Xiaohong
    • Membrane and Water Treatment
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    • v.10 no.4
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    • pp.287-298
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    • 2019
  • Lotus leaf has a special dual micro and nano surface structure which gives its highly hydrophobic surface characteristics and so-called self cleaning effect. In order to endow PVDF hollow fiber membrane with this special structure and improve the hydrophobicity of membrane surface, PVDF hollow fiber composite membranes was obtained through the immersion coating of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) dilute solution on the outside surface of PVDF support membrane. The prepared PVDF composite membranes were used in the vacuum membrane distillation (VMD) for the desalination. The effects of PVDF-HFP dilute solution concentration in the dope solution and coating time on VMD separation performance was studied. Membranes were characterized by SEM, WCA measurement, porosity, and liquid entry pressure of water. VMD test was carried out using $35g{\cdot}L^{-1}$ NaCl aqueous solution as the feed solution at feed temperature of $30^{\circ}C$ and the permeate pressure of 31.3 kPa. The vapour flux reached a maximum when PVDF-HFP concentration in the dilute solution was 5 wt% and the coating time was kept in the range of 10-60 s. This was attributed to the well configuration of micro-nano rods which was similar with the dual micro-nano structure on the lotus leaf. Compared with the original PVDF membrane, the salt rejection can be well maintained which was greater than 99.99 % meanwhile permeation water conductivity was kept at a low value of $7-9{\mu}S{\cdot}cm^{-1}$ during the continuous testing for 360 h.

Gas Permeation Properties of Hydrocarbon/$N_2$ Mixture through PEI-PDMS Hollow Fiber Composite Membranes (Hydrocarbon/$N_2$ 혼합물의 분리를 위한 PEI-PDMS 중공사 복합막의 기체 투과 특성)

  • Lee, Chung Seop;Cho, Eun Hye;Ha, Seong Yong;Rhim, Ji Won
    • Membrane Journal
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    • v.22 no.4
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    • pp.251-257
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    • 2012
  • For the separation and recovery of n-pentane from nitrogen environment, the poly (dimethyl siloxane) (PDMS) composite membranes supported by polyetherimide (PEI) hollow fiber membranes were prepared. To characterize the gas separation properties of the resulting membranes, the permeance of n-pentane and nitrogen, concentrations of permeate and retentate, and recovery ratio were measured for n-pentane and nitrogen mixtures. The permeance of n-pentane and nitrogen, 2485.3 and 9.9 GPU, were observed respectively. As the stage cut decreases and the feed concentration increases, the n-pentane concentration in permeate tends to increase. In the meanwhile, the recovery efficiency tends to increase as the stage cut increases and the feed concentration decreases.

Improvement of Mechanical and Interfacial Properties of Carbon Fiber/Epoxy Composites by Adding Nano SiC Fillers (나노 SiC 입자의 형상에 따른 탄소섬유 강화 에폭시 복합재료의 기계적 및 계면 물성 변화 관찰)

  • Kwon, Dong-Jun;Wang, Zuo-Jia;Kim, Je-Jun;Jang, Key-Wook;Park, Joung-Man
    • Journal of Adhesion and Interface
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    • v.14 no.2
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    • pp.75-81
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    • 2013
  • Epoxy matrix based composites were fabricated by adding SiC nano fillers. The interfacial properties of composites were varied with different shapes of SiC nano fillers. To investigate the shape effects on the interfacial properties, beta and whisker type SiC nano fillers were used for this evaluation. The dispersion states of nano SiC-epoxy nanocomposites were evaluated by capacitance measurements. FE-SEM was used to observe the fracture surface of different structures of SiC-epoxy nanocomposites and to investigate for reinforcement effect. Interfacial properties between carbon fiber and SiC-epoxy nanocomposites were also evaluated by ILSS (interlaminar shear strength) and IFSS (interfacial shear strength) tests. The interfacial adhesion of beta type nanocomposites was better than whisker type.

An on-line process information system for nano-fiber webs (나노 파이버웹의 온.인 공정 정보 시스템)

  • 김주용;임대영;변성원
    • Proceedings of the Korean Fiber Society Conference
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    • 2003.04a
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    • pp.143-145
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    • 2003
  • 전기방사에 의해 제조되는 나노 파이버웹은 섬유가 매우 가늘고, 기공이 미세하며 비표면적이 매우 커서 필터 및 전극재료에 적합한 산업용 소재이다. 나노 웹의 구조는 방사 용액의 농도, 방사 온도, 압력, 전압등 여러 변수들에 의해 영향을 받으며, 이 변수들의 구조에 미치는 영향들이 이론적, 실험적으로 많이 연구, 보고되어 있다 [1]. 그러나, 공정의 분석 및 제어에 대한 연구는 매우 드물며, 특히 대량 생산하에서의 품질 관리 시스템에 대한 연구는 전무한 실정이다. (중략)

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