• Title/Summary/Keyword: interface treatment

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The Evaluation of Crack Propagation in Functionally Graded Materials with Coatings (코팅 경사기능 재료의 균열전파에 관한 평가)

  • Kwon, Oh-Heon
    • Journal of the Korean Society of Safety
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    • v.23 no.4
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    • pp.25-29
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    • 2008
  • Recently, new functionally graded material(FGM) that has a spatial variation in composition and properties is developed because of its good quality. This material yields the demands for resistance to corrosion and high temperature in turbine blade, wear resistance as in gears and high strength machine parts. Especially coating treatment in FGM surface brings forth a mechanical weak at the interface due to discontinuous stress resulting from a steep material change. It often, leads cracks or spallation in a coating area around an interface. The behavior of propagation cracks in FGMs was here investigated. The interface stresses were reduced because of graded material properties. Also graded material parameter with exponential equation was founded to influence the stress intensity factor. And the resistance curve with FGM coating was slightly increased.

Interfacial phenomena of XLPE/EPDM laminates (XLPE/EPDM laminates의 계면현상)

  • 남진호;서광석;김지환;고광철
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1998.11a
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    • pp.211-214
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    • 1998
  • DC breakdown characteristics and formation of space charge at the interfaces of crosslinked polyethylene (XLPE) /ethylene propylene diene terpolymer (EPDM) laminates were studied. Effects of silicone grease and some chemicals such as crosslinking coagent on the interfacial charge were also studied. Interfacial charge develops at the interface of XLPE/EPDM laminates, which changes depending on heat treatment conditions and types of chemicals coated at the interface. Some chemicals such as maleic anhydride reduce the accumulation of interfacial charge in the XLPE/EPDM laminates. Breakdown strength of EPDM/XLPE laminate through the interface was highest when silicone oil was pasted in the interfaces. Interfacial breakdown strength decreased with the increase of MAH content.

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Interface formation between tris-(8-hydroxyquinoline) aluminum and room temperature stable electride: C12A7:$e^-$

  • Kim, Ki-Beom;Kikuchi, Maiko;Miyakawa, Masashi;Yanagi, Hiroshi;Kamiya, Toshio;Hirano, Masahiro;Hosono, Hideo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.235-238
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    • 2006
  • Interface formation between $12CaO{\cdot}7Al_2O_3(C12A7:e^-)$ and Alq3 was investigated using in-situ ultra-violet photoelectron spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS). The work function and vacuum level shift of $C12A7:e^-$ were change by different surface treatment from 2.6eV to 4.2eV. Also vacuum level shift $(\Delta)$ at the interface were from +0.3eV to -0.3eV.

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Accurate and Efficient Re-evaulation of Cell-interface Convective Fluxes (다차원 압축성 유동의 격자 경계면 대류 플럭스 계산을 위한 새로운 수치기법 연구)

  • Yoon S. H.;Kim S. S.;Kim K. H.;Kim C.
    • 한국전산유체공학회:학술대회논문집
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    • 2004.10a
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    • pp.3-6
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    • 2004
  • In order to reduce the excessive numerical dissipation which is induced when a grid system is not aligned with a discontinuity, a new spatial treatment of cell-interface fluxes is introduced. The M-AUSMPW+ in this paper has the formula that has an additional procedure of re-defining transferred properties at a cell-interface, based on AUSMPW+. The newly defined transferred property could eliminate numerical dissipation effectively in non-flow aligned grid system of multi-dimensional flows.

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A Study on the Strength of Geotextile and the Influence of Settlement in a Waste Landfill (폐기물 매립지 인공합성 차수재 강도와 침하영향에 관한 연구)

  • 장연수;임학수;권강오
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2000.11a
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    • pp.241-245
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    • 2000
  • In this paper, the results of the direct shear interface friction test is introduced to understand interface friction between geosynthetic materials that are required for analyzing slope stability of the liner system of waste landfills. Tensile stresses that occur in a liner system due to differential settlement with waste load are estimated using FLAC. It was shown that HDPE/geocomposite inteface friction angle is 11.9$^{\circ}$, HDPE/wastes is 12.0$^{\circ}$ and geotextile/wastes is 28.0$^{\circ}$. Tensile stress due to settlement in a foundation of landfill is well within the limits of tensile strength regulated by waste treatment law.

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Reliability study of Sn-Zn lead-free solder for SMT application (표면실장 적용을 위한 Sn-Zn 무연 솔더의 신뢰성 연구)

  • Yun, Jeong-Won;Jeong, Seung-Bu
    • Proceedings of the KWS Conference
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    • 2005.11a
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    • pp.219-221
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    • 2005
  • Sn-9Zn solder balls were bonded to Cu, ENIG (Electroless Nickel/Immersion Gold) and electrolytic Au/Ni pads, and the effect of aging on their joint reliability was investigated. The interfacial products were different from the general reaction layer formed in a Sn-base solder. The intermetallic compounds formed in the solder/Cu joint were $Cu_{5}Zn_{8}$ and $Cu_{6}Sn_{5}$. After aging treatment, voids formed irregularly at the bottom side of the solder because of Sn diffusion into the $Cu_{5}Zn_{8}$ IMC. In the case of the solder/ENIG joint, $AuZn_{3}$ IMCs were formed at the interface. In the case of the Au/Ni/Cu substrate, an $AuZn_{3}$ IMC layer formed at the interface due to the fast reaction between Au and Zn. In addition, the $AuZn_{3}$ IMC layer became detached from the interface after reflow. When the aging time was extended to 100 h, $Ni_{5}Zn_{21}$ IMC was observed on the Ni substrate.

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Posttraumatic Stiffness (외상 후 동결견)

  • Choi, Chang-Hyeok
    • Clinics in Shoulder and Elbow
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    • v.9 no.1
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    • pp.14-19
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    • 2006
  • The patient with a posttraumatic stiffness frequently has a history of prolonged immobilization after a traumatic event. Adhesions in the extraarticular humeroscapular motion interface may be present independently or in combination with intraarticular capsular contractures. A through history and physical examination usually reveal the cause and anatomic location of stiffness. Passive stretching exercise program is effective as a first line treatment, but manipulation under anesthesia is usually not effective because of potential complication such as fracture, tendon rupture and neurologic injury. The humeroscapular motion interface adhesion can be released either open or arthroscopically. The combined technique coupled with an aggressive rehabilitation program can provide more effective motion restoration and pain relief.

Changes in Adhesion Interface between Rubber and Steel Cord with Aging Treatment (열화처리에 따른 고무와 강선코드간 접착계면의 변화)

  • Seo, Gon;Sohn, Bongyoung
    • Applied Chemistry for Engineering
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    • v.5 no.4
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    • pp.630-636
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    • 1994
  • The changes in adhesion interface between rubber compound and brass plated steel cord after various aging treatments were studied by using an Auger electron spectrometer and a scanning electron microscope. After thermal aging, partial oxidation and additional growth of adhesion layer were observed. The adhesion layer and brass were partially removed after humid aging. With dynamic aging the adhesion layer was destroyed and the corrosion of steel core was proceeded. The changes in adhesion interface were discussed in terms of the adhesion properties determined from the stress-strain experiments.

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Structural Performance of Flexural Members Enlarged with Epoxy Mortar System at Soffit (변형에폭시계 재료를 사용한 하부증대 보의 구조적 성능)

  • 홍건호;조하나;신영수;정혜교
    • Proceedings of the Korea Concrete Institute Conference
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    • 1998.10b
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    • pp.833-838
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    • 1998
  • This paper is aimed to investigate structural performance of flexural members enlarged with epoxy mortar at soffit. Main test variables are steel ratio and interface treatment method and six test beams are tested to investigate the effect of each test variables on maximum load capacity, load-deflection and moment-curvature relationship, interface behavior and failure mode. Test results show that section enlarged beams can carry almost same load of the monolithic beams with same size and the flexural stiffness and cracking moments are increased about 2.5 times and 50 to 70%of failure moment in comparison with same sized control beam, respectively. However, deflections and curvatures are decreased at the same load and interface fractures are not discovered at the ultimate load.

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Effect of VC Addition on the Microstructural Evolution of Fe-TiC Cermet (VC의 첨가에 따른 Fe-TiC계의 미세조직변화)

  • 채기웅
    • Journal of the Korean Ceramic Society
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    • v.36 no.4
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    • pp.366-371
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    • 1999
  • The effect of VC addition on the microstructural evolution of Fe-TiC cermet has been investigated. The microstructures of the Fe-TiC varied with the amount of VC addition. The addition of 1wt% VC enhanced the instability of liquid-solid interface ; the dissolving interface showed round shape instead of facetted one which was ascribed to the increase of lattice mismatch between TiC and solid-solution carbide. in the speci-men with 10wt% VC the new set of solid-solution carbide grains of uniform and small size was formed in-side coarse TiC particles by diffusion induced recrystallizatin (DIR). With increasing the heat-treatment time fine recrystallized grains were dispersed homogeneously in the matrix and resulted in the increase in fracture strength.

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