• Title, Summary, Keyword: Adhesion

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Adhesion Reliability Enhancement of Silicon/Epoxy/Polyimide Interfaces for Flexible Electronics

  • Kim, Sanwi;Kim, Taek-Soo
    • Journal of the Microelectronics and Packaging Society
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    • v.19 no.3
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    • pp.63-69
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    • 2012
  • Adhesion and mechanical reliability of silicon/epoxy/polyimide interfaces are critical issues for flexible electronics. Bonds between these interfaces are mainly hydrogen bonds, so their adhesion is weaker than cohesive fracture toughness and vulnerable to moisture. In order to enhance adhesion and suppress moisture-assisted debonding, UV/Ozone treatment and innovative sol-gel derived hybrid layers were applied to silicon/epoxy/polyimide interfaces. The fracture energy and subcritical crack growth rate were measured by using a double cantilever beam (DCB) fracture mechanics test. Results showed that UV/Ozone treatment increased the adhesion, but was not effective for improving reliability against humidity. However, by applying sol-gel derived hybrid layers, adhesion increase as well as suppresion of moisture-assisted cracking were achieved.

Wheel/Rail Adhesion for Improvement of Braking Performance (철도차량의 제동성능 향상을 위한 점착현상에 관한 연구)

  • 전규찬;황동환;김대은
    • Tribology and Lubricants
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    • v.13 no.2
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    • pp.68-73
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    • 1997
  • The adhesion between wheel and rail plays an important role in the braking performance of trains. Though there have been numerous studies on the characteristics of adhesion phenomenon, a general understanding from the physical point of view is still lacking. In this work, the adhesion mechanism between wheel and rail was investigated by studying the mechanisms of pure rolling and sliding experiments. Tests were performed under various conditions to determine the physical phenomenon responsible for adhesion between wheel and rail. The results of this study is expected to aid in improving the braking performance of trains.

Re-adhesion Control for Wheeled Robot Using Fuzzy Logic (퍼지 제어기를 이용한 이동 로봇의 재점착 제어)

  • Kwon, Sun-Ku;Huh, Uk-Youl;Kim, Hak-Il
    • Proceedings of the KIEE Conference
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    • pp.2423-2425
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    • 2004
  • Mobility of an indoor wheeled robot is affected by adhesion force that is related to various floor conditions. When the adhesion force between driving wheels and the floor decreases suddenly, the robot has slip state. First of all, this paper models adhesion characteristics and slip in wheeled robot. Secondly, the paper proposes estimation method of adhesion force coefficient(AFC) according to slip velocity. In order to overcome this slip problem, optimal slip velocity must be decided for stable movement of wheeled robot. The paper proposes an anti-slip control system based on an ordinary disturbance observer, that is, the re-adhesion control is achieved by reducing the driving torque enough to give maximum adhesion force coefficient. fuzzy logic controller(FLC) is petty useful with slip through that compare fuzzy with PI control for the controller performance. These procedure is implemented using a Pioneer 2-DXE parameter.

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Anti-Slip Control for Wheeled Robot Based on Disturbance Observer (외란 관측기를 이용한 이동 로봇의 슬립 제어)

  • Kwon, Sun-Ku;Huh, Uk-Youl;Kim, Jin-Whan;Kim, Hak-Il
    • Proceedings of the KIEE Conference
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    • pp.50-52
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    • 2004
  • Mobility of an indoor wheeled robot is affected by adhesion force that is related to various floor conditions. When the adhesion force between driving wheels and the floor decreases suddenly, the robot has slip state. First of all, this paper models adhesion characteristics and slip in wheeled robot. Secondly, the paper proposes estimation method of adhesion force coefficient according to slip velocity. In oder to overcome this slip problem, optimal slip velocity must be decided for stable movement of wheeled robot. The paper proposes an anti-slip control system based on an ordinary disturbance observer, that is, the anti-slip control is achieved by reducing the driving torque enough to give maximum adhesion force coefficient. These procedure is implemented using a Pioneer 2-DXE parameter.

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Involvement of Extracellular Matrix and Integrin-like Proteins on Conidial Adhesion and Appressorium Differentiation in Magnaporthe oryzae

  • Bae, Cheol-Yong;Kim, Soon-Ok;Choi, Woo-Bong;Lee, Yong-Hwan
    • Journal of Microbiology and Biotechnology
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    • v.17 no.7
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    • pp.1198-1203
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    • 2007
  • Conidial adhesion and appressorium formation of Magnaporthe oryzae on the rice surface are important early events in the infection process. As an initiative step to understand the mechanisms underlying these cellular processes at a biochemical level, the effect of a human fibronectin antibody (HFA) and RGD peptides on conidial adhesion and appressorium formation was evaluated. HFA inhibited conidial adhesion and appressorium formation in a dosage-dependent manner. RGD peptides also inhibited these cellular events. Conidial adhesion and appressorium formation inhibited by RGD peptides were restored by chemicals involved in the cyclic AMP-dependent signaling pathway. These results suggest that extracellular matrix proteins might be involved in conidial adhesion and appressorium formation through integrin-like receptor mediation and modulation of cAMP-dependent signaling in the cells.

Laser Welding Parameter Variations and its Application for Plastic Adhesion

  • Park, Sung-Jin;Park, Sung-Joon;Park, Hae-Young;Park, Jae-Wook;Sim, Ji-Young;Choi, Jin-Young;Kim, Hee-Je
    • Journal of Electrical Engineering and Technology
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    • v.2 no.1
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    • pp.112-117
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    • 2007
  • a parametric investigation was conducted to evaluate the effect of the laser beam for plastic adhesion. To determine the best condition for plastic adhesion, the $CO_2$(wavelength $10.6{\mu}m$) and nd:yag(wavelength $10.6{\mu}m$) laser were experimented with. From the experiment results obtained, the nd:yag laser was revealed to be the most suitable for plastic adhesion. In this study, three adhesion parameters such as input power level, working time of laser beam and pps(pulse per second) were systematically adjusted for suitable adhesion. From these experiments, it was observed that the target plastic melted and was evaporated by the nd:yag laser. Furthermore, the relationships between adhesive surface by laser beam and above three parameters were discovered.

Four Point Bending Test for Adhesion Testing of Packaging Strictures: A Review

  • Mahan, Kenny;Han, Bongtae
    • Journal of the Microelectronics and Packaging Society
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    • v.21 no.4
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    • pp.33-39
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    • 2014
  • To establish the reliability of a packaging structures, adhesion testing of key interfaces is a critical task. Due to the material mismatch, the interface may be prone to delamination failure due to conditions during the manufacturing of the product or just from the day-to-day use. To assess the reliability of the interface adhesion strength testing can be performed during the design phase of the product. One test method of interest is the four-point bending (4PB) adhesion strength test method. This test method has been implemented in a variety of situations to evaluate the adhesion strength of interfaces in bimaterial structures to the interfaces within thin film multilayer stacks. This article presents a review of the 4PB adhesion strength testing method and key implementations of the technique in regards to semiconductor packaging.

Development of Polymeric Layer for Enhancing The Adhesion of Nano-devices Fabricated by The Nanotransfer Molding Method

  • Lee, Gi-Seok;Seong, Myeong-Mo
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.634-634
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    • 2013
  • Transfer molding methods have a problem that weak adhesion between nanostructures and substrates. It is important to make various nano scale applications, also the stability of nanostructure on substrate is related with device performance. We studied an effect of poly 4-vinylphenol (PVP) as the polymeric adhesion layer between organic nanowires and a Si substrate when the nanowires are transferred by liquid-bridge-mediated nanotransfer molding method (LB-nTM). Their structural stability was examined by optical microscopy, scanning electron microscopy as multiple transfer molding and washing process. Field-effect transistors were fabricated with organic semiconductor nanowires on a polymeric adhesion layer and their electrical properties showed no significant difference as the one without the adhesion layer. As a result, adhesion layer can be used in the washing process and making multi-layer nano-scale patterns.

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Allicin Reduces Adhesion Molecules and NO Production Induced by γ-irradiation in Human Endothelial Cells

  • Son, Eun-Wha;Cho, Chul-Koo;Pyo, Suhkneung
    • IMMUNE NETWORK
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    • v.2 no.1
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    • pp.6-11
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    • 2002
  • Background: Inflammation is a frequent reaction following therapeutic irradiation. Since the upregulation of adhesion molecules on endothelial cell surface is known to be associated with inflammation, the expression of adhesion molecules is an important therapeutic target. Methods: Treatment of human umbilical endothelial cells (HUVECs) with ${\gamma}$-irradiation (${\gamma}IR$) induces the expression of adhesion proteins such as intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin. Changes in the expression of these proteins on ${\gamma}$-irradiated HUVECs which had been treated previously with allicin were measured by ELISA. Results: In the present study, we demonstrate that allicin inhibits the ${\gamma}IR$ induced expression of ICAM-1, VCAM-1, and E-selectin on HUVEC in a dose-dependent manner. Allicin was also found to inhibit the ${\gamma}IR$ induced production of nitric oxide (NO). Conclusion: These data suggest that allicin has a therapeutic potential for the treatment of various inflammatory disorders associated with increase numbers of endothelial leukocyte adhesion molecules.