• Title/Summary/Keyword: Wall adhesion

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Numerical Simulation of NIL Process Based on Continuum Hypothesis (연속체 가정을 통한 NIL 공정의 전산모사)

  • Kim, Seung-Mo;Lee, Woo-Il
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.532-537
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    • 2007
  • Nano imprint lithography(NIL) is a cost-efficient, high-throughput processing technique to transfer nano-scale patterns onto thin polymer films. Polymers used as the resist include UV cured resins as well as thermoplastics such as polymethyl-methacrylate(PMMA). In this study, an analytic investigation was performed for the NIL process of transferring nano scale patterns onto polymeric films. Process optimization calls for a thorough understanding of resist flow during the process. We carried out 2D and 3D numerical analyses of resist flow during NIL process. The simulation incorporated continuum-hypothesis and the effects of surface tension were taken into account. For a more effective prediction of free surface, fixed grid scheme with the volume of fluid (VOF) method were used. The simulation results were verified with experimental results qualitatively. And the parametric study was performed for various process conditions.

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Transparent carbon nanotube field emission devices for field emission display and lamp

  • Cho, You-Suk;Lee, Se-Min;Park, Hee-Yong;Lee, Sun-Hee;An, Myung-Chan;Jeong, Se-Young;Kim, Do-Jin
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.1233-1234
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    • 2006
  • A simple new method to fabricate transparent carbon nanotube field emission devices was developed. The highly graphitized single wall carbon nanotubes were attached on Sn/ITO glass by arc discharge method. Post heat treatments below the deformation temperature of soda-lime glass guaranteed a good mechanical adhesion and electrical contact of the nanotubes. The Sn layer was oxidized below $400^{\circ}C$ and became transparent. As increasing the oxidation temperatures, the emission properties became stable and life time of emitter has been increased.

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CFD analysis on the behavior of liquid water in flow channel of PEM fuel cell (PEM 연료전지 유로에서 물의 거동에 대한 CFD 해석)

  • Kim, Hyun-Il;Nam, Jin-Hyun;Shin, Dong-Hoon;Chung, Tae-Yong;Kim, Young-Gyu
    • 한국신재생에너지학회:학술대회논문집
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    • 2007.11a
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    • pp.23-26
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    • 2007
  • Liquid water in flow channel is an important factor that limits the steady and transient performance of PEM fuel cells. A computational fluid dynamics study based on the volume-of-fluid (VOF) multi-phase model is conducted to understand the transport behavior of liquid water in flow channel. The liquid water transport in $180^{\circ}$ bends is investigated and the effect of chamfering is discussed. The effect of wall adhesion is also considered by varying the contact angle of channel surfaces. The result of this study is believed to provide a useful guideline for design optimization of flow patterns or channel configurations of PEM fuel cells.

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Fabrication and Characterization of Window Metallization Pattern for Optical Module Package (광모듈 패키지용 Window 의 Metallization Pattern 제작 및 특성 평가)

  • Jo Hyeon Min;Dan Seong Baek;Ryu Heon Wi;Gang Nam Gi
    • Proceedings of the International Microelectronics And Packaging Society Conference
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    • 2003.11a
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    • pp.239-242
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    • 2003
  • Optical module package is a hermetic metal-ceramic package for carrying optical IC. In case of LD(laser diode) module, window is used for both the path of optical signal and hermetic sealing of package. So, window has the metallization pattern on the surface for brazing process with package wall. In this study, several method were investigated for metallization. Thin film, thick film and mixed method were used for fabrication of metallization pattern. After brazing process, hermeticity and adhesion strength were tested for characterization of metallization pattern.

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Analysis for the Pulse-Jet Cleaning Flow of a Hot Gas Ceramic-Filter Element (고온고압 세라믹 여과재 탈진 과정의 유동 해석)

  • Park I. W.;Ryu J. H.;Choi D. H.
    • 한국전산유체공학회:학술대회논문집
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    • 1998.05a
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    • pp.110-115
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    • 1998
  • An axisymmetric Navier-Stokes procedure has been developed to analyze the pulse jet flow in a ceramic filter unit for the dust dislodging process. Using Baldwin-Lomax turbulence model as a closure relationship, the SIAF(Scalar Implicit Approximate Factorization) algorithm together with the ${\delta}^k-Correction$ iterative time marching scheme is adopted to solve the unsteady compressible Navier-Stokes equations. After some validation tests, the code has been applied to solve the pulse jet flow and examine the effects of geometry and reservoir pressure condition on the pressure level inside the filter unit. To avoid dealing with the uncertainty of such factors as the cohesion of the collected dust and the adhesion of the dust to the medium and also to simplify the analysis, the filter wall is assumed to be impermeable. The results for various test cases are presented.

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Inhibition of Atherosclerotic Lesion by KR-31378 in LDL Receptor Null Mice

  • Kim, Jiyun;Nam, Ki-Hoan;Choi, Jae-Hoon;Kim, Hyoung-Chin;Yang, Sung-Don;Kang, Joo-Hyung;Ryu, Young-Han;Kim, Eun-Young;Kim, Sun-Ok;Yoo, Sung-Eun;Oh, Goo-Taeg
    • Proceedings of the Korean Society of Toxicology Conference
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    • 2003.10b
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    • pp.195-195
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    • 2003
  • The recruitment and infiltration of monocytes into the artery wall is a crucial early step in atherogenesis. KR-31378 has been shown to be a neuroprotective agent in rat brain via its potent antioxidant and antiapoptotic actions. Here, we report the effects of this compound on atherogenesis, and some possible mechanisms of action.(omitted)

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A Study on the Electromagnetic Pulse Shielding Effect of Concrete Wall Sprayed with Cu-based Metal (Cu계 금속을 용사한 콘크리트 벽체의 전자파 차폐 성능에 관한 연구)

  • Jang, Jong-Min;Lee, Han-Seung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2020.11a
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    • pp.18-19
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    • 2020
  • The ElectroMagnetic Pulse (EMP) destroys social infrastructure at once and causes social chaos. However, currently major infrastructures are constructed of concrete that does not have electromagnetic shielding performance. In this study, using the arc metal spraying method is used to evaluate the shielding performance and construction performance of concrete. The electro-magnetic shielding effect is measured by fabricating a shielding room with reference to MIL-STD-188-125, and the construction performance is evaluated by measuring the adhesion strength of thin metal sprayed film-concrete. As a result of the study, when the metal spraying method is applied, the shielding effect is higher than that of the special electro-magnetic shielding concrete, and it is considered to be more economical than the existing metal plate (3~5 mm).

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A look at rooftop waterproofing methods that combine a circular adhesive insulated composite duplex exposure repellent with a airvent (원형 접착 절연형의 복합 복층형 노출 방수제와 탈기관을 결합한 옥상 방수 공법에 관한 고찰)

  • KIM, Yeong-Seok;JEON, Sang-Hoon
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2021.11a
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    • pp.236-237
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    • 2021
  • In the waterproofing of the rooftop of reinforced concrete buildings, it is difficult to solve perfectly according to the proficiency of waterproofing materials, methods, and mechanics. Therefore, this study applies a Tricot Fabric Mesh to the behavior of the bottom concrete. In addition, it responds to the behavior of the concrete cracking, and the waterproofing and protective layer has developed a method to provide convenience for rooftop floor use by adhesion between the base and the waterproof layer with the use of high viscosity urethane to effectively move the surface deformation and surface vapor and install a airvent device on the wall.

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Study about cracking reducing of the concrete by utilizing fiber-reinforced admixture (무근콘크리트 균열저감을 위한 배합설계 및 시공프로세스 수립에 대한 연구)

  • Kim, Dae-Geon;Choi, Sang-Hwan;Moon, Gyeong-Sik;Jo, Man-Ki;Han, Min-Cheol;Han, Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2014.05a
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    • pp.140-141
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    • 2014
  • Nowadays, as to increased the workability of the press concrete and decrease the cracking, the fiber-reinforced admixture has been widely used. As the low adhesion force between the paste and fiber-reinforced admixture, it was considered as could not be used in the structure. Even more, as the loss of flowability and the exposure of the fiber, further study is needed. In this study, as the different environment and position of the building, the dosages of the fiber-reinforced admixture has also been changed. The fundamental properties and cracking of fiber-reinforced concrete have been tested.

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The Effects of Enamel Matrix Derivative and Calcium Sulfate Paste on the Healing of 1-Wall Intrabony Defects in Beagle Dogs (성견 1면 치조골 결손부에서 $Emdogain^{(R)}$$Emdogain^{(R)}$ 및 특수 제조된 Calcium Sulfate Paste 혼합물이 치주조직 치유에 미치는 영향)

  • Choi, Seong-Ho;Kim, Chang-Sung;Suh, Jong-Jin;Kim, Hyun-Young;Kim, Jeong-Hye;Cho, Kyoo-Sung;Kim, Chong-Kwan
    • Journal of Periodontal and Implant Science
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    • v.30 no.3
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    • pp.539-555
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    • 2000
  • Recently, it was reported that enamel matrix derivative may be beneficial in periodontal regeneration procedures in expectation of promoting new bone and cementum formation. The aim of present study was to evaluate the effect of enamel matrix derivative($Emdogain^?$)and Caso4 sulfate paste in 1-wall intrabony defects in beagle dogs. Surgically created 1-wall intrabony defects were randomly assigned to receive root debridement alone or $Emdogain^{(R)}$ or $Emdogain^{(R)}$ and Caso4. Clinical defect size was 4 X 4mm. The control group was treated with root debridement alone,and Experimental group I was treated with enamel matrix derivative application, and Experimental group II was treated with enamel matrix derivative and Caso4 sulfate paste application,. The healing processes were histologically and histometrically observed after 8 weeks and the results were as follows: 1. The length of junctional epithelium was $0.41{\pm}0.01mm$ in the control group, $0.42{\pm}0.08mm$in the experimental group I and $0.50{\pm}0.13mm$in the experimental group II. 2. The connective tissue adhesion was $0.28{\pm}0.02mm$ in the control group, $0.13{\pm}0.08mm$ in the experimental group I and $0.19{\pm}0.02mm$ in the experimental group II. 3. The new cementum formation was $3.80{\pm}0.06mm$ in the control group, $4.12{\pm}0.43mm$ in the experimental group I and $4.34{\pm}0.71mm$ in the experimental group II. 4. The new bone formation was $1.43{\pm}0.03mm$ in the control group, $1.53{\pm}0.47mm$ in the experimental group I and $2.25{\pm}1.35mm$ in the experimental group II. Although there was limitation to present study, the use of enamel matrix derivative in the treatment of periodontal 1-wall intrabony defect enhanced new cementum and bone formation. Caso4 sulfate paste will be the candidate for carriers to deliver enamel matrix derivative, and so enhance the regenerative potency of enamel matrix derivative.

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