• 제목/요약/키워드: Properties of materials

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Effects of E-beam treatment on the interfacial and mechanical properties of henequen/polypropylene composites

  • Cho, Dong-Hwan;Lee, Hyun-Seok;Han, Seong-Ok;Drzal, Lawrence T.
    • Advanced Composite Materials
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    • v.16 no.4
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    • pp.315-334
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    • 2007
  • In the present study, chopped henequen natural fibers without and with surface modification by electron beam (E-beam) treatment were incorporated into a polypropylene matrix. Prior to composite fabrication, a bundle of raw henequen fibers were treated at various E-beam intensities from 10 kGy to 500 kGy. The effect of E-beam intensity on the interfacial, mechanical and thermal properties of randomly oriented henequen/polypropylene composites with the fiber contents of 40 vol% was investigated focusing on the interfacial shear strength, flexural and tensile properties, dynamic mechanical properties, thermal stability, and fracture behavior. Each characteristic of the material strongly depended on the E-beam intensity irradiated, showing an increasing or decreasing effect. The present study demonstrates that henequen fiber surfaces can be modified successfully with an appropriate dosage of electron beam and use of a low E-beam intensity of 10 kGy results in the improvement of the interfacial properties, flexural properties, tensile properties, dynamic mechanical properties and thermal stability of henequen/polypropylene composites.

Polyvalent Nanoparticle-oligonudleotide conjugates: Synthesis, Properties, and Biodiagnostic/Therapeutic Applications

  • Lee, Jae-Seung
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2009.05a
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    • pp.7.2-7.2
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    • 2009
  • Polyvalent nanoparticle-DNA conjugates exhibit a variety of unique features such as programmable assembly and disassembly, sharp melting transitons, intense optical properties, high stability, enhanced binding properties, and easy fabrication of the surface nature by chemical and physical modification. The unique properties of nanoparticle-DNA conjugates enable one to build up a number of versatile assay schemes for the detection of various targets. In addition, nanoparticle-RNA conjugates also demonstrate great promise of therapeutic applications in the context of RNA interference when combined with polymeric materials. In this presentation, representative examples of each aspect of nanoparticle-oligonucleotide conjugates will be discussed.

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Fabrication and Mechanical Properties of A356/SiCp Manufactured by Gas-Particle Co-injection Method (가스-입자 동시주입법에 의한 A356/SiCp 복합재료의 제조 및 기계적 특성)

  • Lee, Jung-Mu;Kang, Suk-Bong;Eum, Chil-Yong;Lim, Cha-Yong
    • Journal of Korea Foundry Society
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    • v.21 no.1
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    • pp.33-40
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    • 2001
  • Among the many techniques available to synthesis metal matrix composites, liquid phase processing, especially, conventional casting process such as stir-casting process is particularly attractive for their simplicity, economy and flexibility, In the present study, A356/20%SiCp composites were fabricated by gas-particle co-injection method. The gas-particle co-injection method is a modified stir-casting method and the corporation of particle could be improved by acceleration of particles due to rotation of impeller and gas purging. The microstructures and mechanical properties such as tensile properties and resistance to wear of fabricated materials were examined. Further, the particle injection mechanism in gas-particle co-injection method was discussed.

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Mechanical Properties of Al-Si Composite Powders produced by Gas Atomization Process

  • Kim Jin-Chun;Wang Li-Fe;Chung In-Sang;Kim Yong-Jin
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2004.11a
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    • pp.46-47
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    • 2004
  • The microstructure and mechanical properties of the hypereutectic prealloyed Al-Si powders prepared by the gas atomization process were described in this paper. With increasing the gas pressure of the atomization, the average powder size was decreased from about $145{\mu}m\;to\;80{\mu}m$. The primary eutectic Si particles were uniformly distributed in the Al matrix and their size varied in the range of $8-10{\mu}m$. The high densified specimens with above 96% of the theoretical density were fabricated the hot pressing process. The UTS mechanical properties of VN1 specimens were much higher than that of conventional hypoeutectic Al-Si alloys.

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Microstructure and magnetic properties of nanocomposite permanent magnetic materials

  • Cheng, Zhao-hua
    • Proceedings of the Korean Magnestics Society Conference
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    • 2002.12a
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    • pp.22-22
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    • 2002
  • It is well known that nanoscale magnetic materials can exhibit significantly different magnetic properties than the corresponding bulk materials. In present work, we summarized the preparation, microstructure, Mossbauer study and magnetic properties of nanocomposites. It was found that both grain size and the amount of magnetically soft phase ${\alpha}$-Fe play a very important role in determining the magnetic properties. (omitted)

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Effect of Reinforcing Materials on Properties of Molten Carbonate Fuel Cell Matrices

  • Moon, Young-Joon;Lee, Dokyol
    • The Korean Journal of Ceramics
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    • v.2 no.3
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    • pp.142-146
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    • 1996
  • The molten carbonate fuel cell matrices, which are usually made of high surface, fine particle size ${\gamma}-LiAlO_2$ are reinforced with coarse particles of the same material and alumina fibers. An the effects of reinforcing materials on pore characteristics, sintering properties and mechanical properties of the matrices are examined.Among the matrices examined, the highest mechanical reinforcement has been achieved in the one containing 10 wt.% coarse particles and 20 wt.% alumina fibers.

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Evaluation of Interfacial and Mechanical Properties of GF/p-DCPD Composites with Different Sizing Agents (사이징제에 따른 유리섬유/폴리디사이클로펜타디엔 복합재료의 계면물성 및 기계적 물성 평가)

  • Kim, Jong-Hyun;Kwon, Dong-Jun;Shin, Pyeong-Su;Park, Ha-Seung;Baek, Yeong-Min;Park, Joung-Man
    • Composites Research
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    • v.31 no.2
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    • pp.57-62
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    • 2018
  • Interfacial and mechanical properties of neat and two sizing agents coated glass fiber (GF)/polydicyclopentadiene (p-DCPD) composites were evaluated at room and low temperatures, $25^{\circ}C$ and $-20^{\circ}C$. Sizing agents of GFs were extracted using acetone and compared via FT-IR. Surface energy and work of adhesion between GFs and p-DCPD were calculated by dynamic contact angle measurement. Mechanical properties of different GFs were determined using single fiber tensile test and interfacial properties of single GF reinforced DCPD strip were determined using cyclic loading tensile test. Mechanical properties of GFs/p-DCPD composites at room and low temperatures were determined using tensile, compressive, and Izod impact tests. Interfacial and mechanical properties were different with sizing agents of GFs and the optimized condition of sizing agent was found.

Improvement on Interfacial, Thermal, and Water Resistance Properties of Wood Sandwich Composites for Stone Bed using CNT-Animal Glue Adhesive (탄소나노튜브/아교 접착제를 이용한 돌침대용 목재 샌드위치 복합재의 계면, 열적 및 방수특성 증가)

  • Kim, Jong-Hyun;Kwon, Dong-Jun;Shin, Pyeong-Su;Baek, Yeong-Min;Park, Ha-Seung;Moon, Sun-Ok;Park, Joung-Man
    • Composites Research
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    • v.30 no.4
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    • pp.235-240
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    • 2017
  • Animal glue, a water-soluble adhesive, has been used historically for high-performance traditional furniture despite the disadvantage of weakness against moisture. Many scientists studied the ways to improve water resistance of animal glue. Improvements on the interfacial, thermal, and water resistance properties of wood sandwich composites (WSC) was studied with carbon nanotube (CNT) wt% in animal glue. Real-time temperature of WSC was measured after WSC was heated with increasing CNT wt%. Lap shear test was performed to determine the interfacial properties of wood and animal glue with CNTs. Water resistance properties of animal glue were determined by lap shear test using specimens dipped in water and the results were compared with the dry case. Hydrophobicity of animal glue by static contact angle was correlated with the variation of lap shear test. Interfacial, thermal, and water resistance properties for animal glue were improved with properly added CNTs.