• 제목/요약/키워드: polymer materials

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화학기상응축법으로 제조된 철 나노분말의 산화저항에 관한 연구 (A Study on Oxidation-Resistance of Iron Nanoparticles Synthesized by Chemical Vapor Condensation Process)

  • 이동원;유지훈;배정현;장태석;김병기
    • 한국분말재료학회지
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    • 제12권3호
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    • pp.225-230
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    • 2005
  • In order to prevent the oxide formation on the surface of nano-size iron particles and thereby to improve the oxidation resistance, iron nanoparticles synthesized by a chemical vapor condensation method were directly soaked in hexadecanethiol solution to coat them with a polymer layer. Oxygen content in the polymer-coated iron nanoparticles was significantly lower than that in air-passivated particles possessing iron-core/oxide-shell structure. Accordingly, oxidation resistance of the polymer-coated particles at an elevated temperature below $130^{\circ}C$ in air was $10\~40$ times higher than that of the air- passivated particles.

브레이드 복합재료를 이용한 피뢰기 모듈 제조에 관한 연구 (Manufacture of arrester module using braided composite materials)

  • 한동희;조한구;한세원;박기호
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2002년도 하계학술대회 논문집 C
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    • pp.1467-1469
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    • 2002
  • This paper aims to investigate the characteristics of braided thermoplastic and thermosetting composite and pressure relief for polymer arrester. In general, braided composite has potential for improved impact and delamination resistance. Manufacturing processes of the braided composite could also be automated and could potentially lead to lower costs. Therefore, in consideration of characteristics of pressure relief for polymer arrester, the fabric pattern of braided composite was studied. And polymer arrester module was manufactured with braid.

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Recent Progress in Passive Radiative Cooling for Sustainable Energy Source

  • Park, Choyeon;Park, Chanil;Choi, Jae-Hak;Yoo, Youngjae
    • Elastomers and Composites
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    • 제57권2호
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    • pp.62-72
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    • 2022
  • Passive daytime radiative cooling (PDRC) is attracting increasing attention as an eco-friendly technology that can save cooling energy by not requiring an external power supply. An ideal PDRC structure should improve solar reflectance and emissivity within the atmospheric spectral window. Early designs of photonic crystal materials demonstrated the benefits of PDRC. Since then, functional arrangements of polymer-based radiative cooling materials have played an important role and are rapidly expanding. This review summarizes the known inorganic, organic, and hybrid materials for PDRC. The review also provides a complete understanding of PDRC and highlights its practical applications.

PLGA 다공성 지지체에 함침시킨 DBP젤의 연골재생 효과: In Vivo 실험 (Effect of Demineralized Bone Particle Gel Penetrated into Poly(lactic-co-glycolic acid) Scaffold on the Regeneration of Chondrocyte: In Vivo Experiment)

  • 이윤미;심초록;이유정;김하늘;조선아;송정은;이동원;강길선
    • 폴리머
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    • 제36권6호
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    • pp.789-794
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    • 2012
  • 생체적합성 및 생분해성의 장점을 지닌 PLGA는 우수한 기계적 성질과 분해속도를 조절할 수 있는 장점을 가지고 있지만 소수성으로 인해 세포의 초기부착률이 낮고, 지지체 내부에 영양액의 공급이 원활하지 않다. 본 연구에서는 이러한 단점을 보완하고자 탈미네랄화된 골분(DBP, demineralized bone particle) 젤을 PLGA 지지체에 함침시켰다. 다양한 형태의 지지체 압축강도를 측정한 결과 PLGA/DBP 지지체가 연골과 비슷한 강도를 가지고 있었으며, 이를 바탕으로 DBP젤을 함침시킨 PLGA/DBP젤 지지체를 제작하였다. 연골세포를 파종하여 in vivo 실험을 진행하였고 조직화 정도를 확인하기 위해 H&E, Safranin-O, Alcian blue, Collagen type I 및 Collagen type II 염색을 실시하였다. 그 결과 DBP를 함침시킨 PLGA 지지체에서 GAG, Collagen type I 및 Collagen type II의 높은 발현과 조직화를 보여 연골조직으로 대체할 수 있는 가능성을 확인하였다.

Fabrication of Colloidal Clusters of Polymer Microspheres and Nonspherical Hollow Micro-particles from Pickering Emulsions

  • Cho, Young-Sang;Kim, Tae-Yeol;Yi, Gi-Ra;Kim, Young-Kuk;Choi, Chul-Jin
    • Bulletin of the Korean Chemical Society
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    • 제33권1호
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    • pp.159-166
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    • 2012
  • We have introduced the Pickering emulsion systems to generate novel confining geometries for the selforganization of monodisperse polymer microspheres using nanoparticle-stabilized emulsion droplets encapsulating the building block particles. Then, through the slow evaporation of emulsion phases by heating, these microspheres were packed into regular polyhedral colloidal clusters covered with nanoparticle-stabilizers made of silica. Furthermore, polymer composite colloidal clusters were burnt out leaving nonspherical hollow micro-particles, in which the configurations of the cluster structure were preserved during calcination. The selfassembled porous architectures in this study will be potentially useful in various applications such as novel building block particles or supporting materials for catalysis or gas adsorption.