• Title/Summary/Keyword: coating properties

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Adhesion Performance and Curing Behaviors of Acid-free Acrylic PSAs Using Two Types of Curing Agents (Acid-free 아크릴계 점착제의 접착 물성 및 경화거동 연구)

  • Lee, Seung-Woo;Park, Ji-Won;Kwon, Young-Eun;Kim, Hyun-Joong
    • Journal of Adhesion and Interface
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    • v.12 no.2
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    • pp.67-72
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    • 2011
  • Acrylic pressure-sensitive adhesives are used in many different parts in the world. But acrylic acid in PSAs may occur unexpected results such as corroding adherends or producing by-products when applied within electronic devices. This study employed acrylic PSAs based on 2-ethylhexyl acrylate (2-EHA), 2-hydroxyethyl acrylate (2-HEA) and butyl acrylate (BA) with different coating thickness. There are two types of curing agents. One is methylaziridine derivative (MAZ) and the other is aluminum acetylacetonate (AlACA). This study examined the adhesion performance and curing behaviors using peel strength, probe tack and gel fraction. Also, the viscoelastic properties of acrylic PSAs were investigated from Advanced rheometric expansion system (ARES).

Effects of Plasma on the Surface of Protein Chip Plates (단백질 칩 기판의 플라즈마 효과)

  • Hyun, J.W.;Kim, N.Y.
    • Journal of the Korean Vacuum Society
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    • v.17 no.6
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    • pp.549-554
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    • 2008
  • Nickel Chloride coated protein chip plates were developed by using a spin coating method after $H_2$ plasma treatment. The adsorption ability of histidine tagged protein was investigated at various times of plasma treatment. The properties of the nickel chloride and protein on the surface of the slides were assayed using particle size analysis and the extent of the protein adsorption was determined by using a bio imaging analyzer system. The results show that the ability of protein adsorption decreased as increasing the time of $H_2$ plasma treatment. The mechanism on the ability of protein adsorption at the plate surface is discussed on results and discussions. The results also suggest that the surface stabilization of protein chip plates treated by plasma technology may be applicable in biosensor markets.

Consideration on the Electromagnetic Wave Absorption Properties of the Plasma for the Stealth Technology (은신기술을 위한 플라즈마의 전자기파 흡수 특성에 대한 고찰)

  • In, S.R.
    • Journal of the Korean Vacuum Society
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    • v.17 no.6
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    • pp.501-510
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    • 2008
  • The stealth technology to conceal an aircraft from the vision of a radar have been accomplished by coating the surface with special paints absorbing the electromagnetic wave. Nowadays, researches to utilize characteristics of the plasma-wave interaction for realizing the stealth technology are actively progressed. In this paper, to investigate the physical feasibility of the plasma stealth, calculation results for the required conditions of the plasma cloaking on the aircraft flying in the air for showing the stealth function, using a flat non-magnetized non-uniform plasma model, are reported and discussed.

Recent Development of Laboratory-made Solid-phase Microextraction Fibers on the Application of Food Safety Analysis

  • Zeng, Jingbin;Chen, Jinmei;Chen, Wenfeng;Huang, Xiaoli;Chen, Liangbi;Chen, Xi
    • Food Science and Biotechnology
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    • v.18 no.3
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    • pp.579-585
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    • 2009
  • Solid-phase microextraction (SPME) has gained widespread acceptance in sample pretreatment due to its solvent-free and easy-to-operate properties. SPME fibers are considered as a key part of SPME technique, since it primarily determines the extraction performance of the method including sensitivity, selectivity, and reproducibility. Generally speaking, target analyte with different chemical property requires fiber coating that has the best affinity towards it. Due to the lack of varieties of commercial fibers available currently, considerable efforts have been recently made to develop tailor-made fibers to fulfill increasing demands of different analysis. This paper concisely classify some SPME fiber preparation approaches such as sol-gel technology, physical deposition, molecularly imprinted technique, and their respective application in food safety analysis.

An ultrastructural study of the cuticle in the byssus of marine mussel (Mytilus coruscus) (홍합 (Mytilus coruscus) 족사 cuticle의 초미세구조 연구)

  • Kim, Sangsik;Choi, Seung Hwan;Yoon, Sung Jin;Hwang, Dong Soo
    • Journal of Marine Bioscience and Biotechnology
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    • v.6 no.2
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    • pp.41-46
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    • 2014
  • Mussel byssus is a bundle of threads used to attach mussels to wet substrates. Recently, a thin cuticle layer on the byssus has attracted public attentions due to its remarkable toughness - stiff as epoxy resin and extensible as rubber. Here, we observed ultrastructure of the cuticle layer in a far eastern mussel (Mytilus coruscus) to understand underlying mechanisms for the mechanical properties. The cuticle layer observed by TEM was composed of submicron-sized granular inclusions in a continuous matrix phase. In addition, ultrastructural study in the presence of tertiary amine (Tetraethylammonium, TEA) showed an evidence that the cuticle is stabilized by cation-${\pi}$ interaction.

HMDS Treatment of Ordered Mesoporous Silica Film for Low Dielectric Application (저유전물질로의 응용을 휘한 규칙성 메조포러스 실리카 박막에의 HMDS 처리)

  • Ha, Tae-Jung;Choi, Sun-Gyu;Yu, Byoung-Gon;Park, Hyung-Ho
    • Journal of the Korean Ceramic Society
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    • v.45 no.1
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    • pp.48-53
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    • 2008
  • In order to reduce signal delay in ULSI, an intermetal material of low dielectric constant is required. Ordered mesoporous silica film is proper to intermetal dielectric due to its low dielectric constant and superior mechanical properties. The ordered mesoporous silica film prepared by TEOS (tetraethoxysilane) / MTES (methyltriethoxysilane) mixed silica precursor and Brij-76 surfactant was surface-modified by HMDS (hexamethyldisilazane) treatment to reduce its dielectric constant. HMDS can substitute $-Si(CH_3)_3$ groups for -OH groups on the surface of silica wall. In order to modify interior silica wall, HMDS was treated by two different processes except the conventional spin coating. One process is that film is dipped and stirred in HMDS/n-hexane solution, and the other process is that film is exposed to evaporated HMDS. Through the investigation with different HMDS treatment, it was concluded that surface modification in evaporated HMDS was more effective to modify interior silica wall of nano-sized pores.

Study on the Growth of Monoclinic VO2 Phase Applicable for Thermochromic Ceramic Tile

  • Jung, DaeYong;Kim, Ungsoo;Cho, Wooseok
    • Journal of the Korean Ceramic Society
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    • v.52 no.5
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    • pp.361-365
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    • 2015
  • Vanadium dioxide ($VO_2$) of monoclinic phase exhibits Metal Insulator Phase Transition (MIPT) phenomenon involving a sharp change in electrical and optical properties at $68^{\circ}C$. Solution-based process is applied to form uniform $VO_2$ coating layer on ceramic tiles. This can selectively block the near-infrared light to possibly reduce the energy loss and prevent dew condensation caused by the temperature difference. Heat treatment conditions including temperature and dwell time were examined to obtain a monoclinic $VO_2$ single phase. Both rutile and monoclinic $VO_2$ phases were observed from in the tiles post-annealed below $700^{\circ}C$. Desired monoclinic $VO_2$ single phase was grown in the tiles heat treated at $750^{\circ}C$. Nano facets of irregular size were observed in the monoclinic $VO_2$ phase involving the phase-transition. Grain growth of monoclinic $VO_2$ phase was observed as a function of dwell time at $750^{\circ}C$.

Synthesis and Characterization of CoFe2O4/SiO2 using Cobalt Precursors from Recycling Waste Cemented Carbide (폐 초경합금에서 추출된 Co를 이용한 CoFe2O4/SiO2 합성 및 특성평가)

  • Yu, Ri;Pee, Jae-Hwan;Kim, Yoo-Jin
    • Journal of the Korean Ceramic Society
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    • v.48 no.5
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    • pp.454-457
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    • 2011
  • We report the preparation of nanocrystalline cobalt ferrite, $CoFe_2O_4$, particles using recycled $Co_3O_4$ and their surface coating with silica using micro emulsion method. Firstly, the $Co_3O_4$ powders were separated from waste cemented carbide with acid-base chemical treatment. The cobalt ferrite nanoparticles with the size 10 nm are prepared by thermal decomposition method using recycled $Co_3O_4$. $SiO_2$ was coated onto the $CoFe_2O_4$ particles by the micro-emulsion method. The $SiO_2$-coated $CoFe_2O_4$ particles were studied their physical properties and characterized by X-ray diffraction (XRD), high resolution-transmission electron microscopy (TEM) analysis and CIE Lab value.

Fabrication and Electrical Properities of Semiconducting YBa2Cu3O7-x thin Film or Application of IR Sensors (적외선 센서로의 응용을 위한 반도성 YBa2Cu3O7-x 박막의 제작 및 전기적 특성)

  • Jeong, Jae-Woon;Jo, Seo-Hyeon;Lee, Sung-Gap
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.61 no.9
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    • pp.1296-1299
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    • 2012
  • $YBa_2Cu_3O_{7-x}$ thin films were fabricated by the spin-coating method on $SiO_2$/Si substrate using an alkoxide-based sol-gel method. The structural and electrical properties were investigated for various 1st annealing temperature. Due to the formation of the polycrystalline single phase, synthesis temperature was observed at around $720^{\circ}C-800^{\circ}C$. $YBa_2Cu_3O_{7-x}$ thin films with the 1st annealing temperature of $450^{\circ}C{\sim}500^{\circ}C$ showed the single XRD patterns without the second phase, such as $YBa_2Cu_4O_8$. The thickness of films was approximately $0.23{\mu}m{\sim}0.27{\mu}m$. Aerage grain size, resistance and temperature coefficient of resistance (TCR) of $YBa_2Cu_3O_{7-x}$ thin films with the 1st annealing temperature of $500^{\circ}C$ were $0.27{\mu}m$, $59.7M{\Omega}$ and -3.7 %/K, respecvitely.

Numerical Analysis of Temperature Distribution of the Explosive Material in the Double-Layer Liners (이중층 라이너의 폭발 재료 온도 분포 수치해석)

  • Mun, Sang Ho;Kim, See Jo;Lee, Chang Hee;Lee, Seong
    • Journal of the Korea Institute of Military Science and Technology
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    • v.19 no.2
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    • pp.202-210
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    • 2016
  • The development of new concepts of liner is of great importance to effectively neutralize the enemy's attack power concealed in the protective structure or armored vehicles. A double layer liner has a combination of two different materials, one for penetration of target and the other for explosion after penetration. Therefore, it is of great importance to understand the temperature distribution before impact which should be lower than the explosive temperature of pure explosive material of the liner used. In this study, two different liner materials were obtained using cold spray coating and these material properties were characterized by DSC experiments. Numerical computations were done and the effect of temperature distribution and changes over time at each point of the explosive material depending on the layer types of the liner were discussed and analysed in the jet state.