• Title/Summary/Keyword: over-coating

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Mechanical and Electrical Reliability of Silver Nanowire Film on Flexible Substrate (유연기판 위에 제작된 Silver Nanowire 필름의 기계 및 전기적 신뢰성 연구)

  • Lee, Yo Seb;Lee, Won Jae;Park, Jin Yeong;Choa, Sung-Hoon
    • Journal of the Microelectronics and Packaging Society
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    • v.23 no.4
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    • pp.93-99
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    • 2016
  • In this paper, we investigated the mechanical and electrical reliability of silver nanowire (AgNW) films. In particular, the durability and reliability of AgNW films were studied when the AgNW film was subjected to the bending deformation under current flow. The electrical durability of AgNW was evaluated by observing changes in heat generation and current density occurring in AgNW through voltage and current tests. The AgNW film showed a constant resistance change up to a bending radius of 2 mm and 200,000 cycles in the bending fatigue tests. The over-coating layer has an effect of improving the durability of the AgNW film. In the case of AgNW with the over-coating layer, heat was uniformly dissipated on the surface of AgNW film, whereas in the case of AgNW film without the over-coating layer, heat was generated locally. In the bending test under the current flow, the current density of the AgNW film was continuously decreased up to 52.4%. During bending, the AgNW was deformed due to mechanical deformation such as tensile, bending and sliding of the AgNW, consequently contact resistance of the AgNW was increased, leading to a electrical breakdown of AgNW by Joule heating. It was found that the application of the over-coating layer can improve the electrical and mechanical reliability of the AgNW film.

Heating & Drying Characteristics of Coating Layer by Induction Heating and Short-wave Infrared Heating (유도가열 및 근적외선 가열방법에 의한 표면처리 강판 도포층의 가열 및 건조 특성)

  • Kim T. S.;Yang J. W.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2004.08a
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    • pp.249-257
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    • 2004
  • Drying and curing characteristics of PCM resins using the induction heater and short-wave infrared emitter module was studied to develop a compact oven system for the high speed CCL and post-treatment equipment. Drying of the polyester resins using the induction heater and infrared heater showed that the blistering tendency of polyester resin coating increased regardless of additives and colors of resins as the heating rate and/or dry film thickness increased. The blistering of polyester resin coating layer occurred when the heating speed was over than $25^{\circ}C/sec$ for the dry film thickness of $19\~20um$, which is the typical thickness of finish coating in CCL. So did it when the heating speed was over than $40^{\circ}C/sec$ for the dry film thickness over than 10 um. The heating efficiency of paint coated steels by the infrared heating was strongly dependent on the colors of paint coating and generally increased for the dark surface and/or coating. But the faster drying of the PCM resin coatings increased the blistering tendency of coating layer. The blistering limit for the typical finish coating by the infrared heating was estimated as the heating rate slower than $20^{\circ}C/sec$ regardless of colors of PCM resins.

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Characterization of vanadium carbide coating deposited by borax salt bath process

  • Aghaie-Khafri, M.;Daemi, N.
    • Advances in materials Research
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    • v.1 no.3
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    • pp.233-243
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    • 2012
  • Thermal reactive diffusion coating of vanadium carbide on DIN 2714 steel substrate was performed in a molten borax bath at $950-1050^{\circ}C$. The coating formed on the surface of the substrate had uniform thickness ($1-12{\mu}m$) all over the surface and the coating layer was hard (2430-2700 HV), dense, smooth and compact. The influence of the kinetics parameters, temperature and time, has been investigated. Vanadium carbide coating was characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDX) and X-ray diffraction analysis (XRD). The corrosion resistance of the coating was evaluated by potentiodynamic polarization in 3.5% NaCl solution. The results obtained showed that decrease of coating microhardness following increasing time and temperature is owing to the coarsening of carbides and coating grain size.

A Study on the Optical Properties of Eye-glasses (안경렌즈의 광학적 성능에 관한 연구)

  • Lim, Hyeon Seen;Ji, Taek Sang;Kim, Bong Hwan
    • Journal of Korean Ophthalmic Optics Society
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    • v.2 no.1
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    • pp.31-43
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    • 1997
  • In this paper, the rate of transmittance regarding the home -and foreign-made lens that have been treated with multi coating and no coating has been studied in the range of the visible ray. The lens that were treated with No Coating turned out to be about 93% of the rate of transmittance, but those treated with Coating turned out to be over 98%. Especially, the rate of transmittance of product made by a company in a foreign country turned out to be homogeneous in the whole range.

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Gelatin Coating on Quality Attributes of Sausage during Refrigerated Storage

  • Shon, Jin-Han;Eo, Ji-Hyun;Choi, Yong-Hwa
    • Food Science of Animal Resources
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    • v.31 no.6
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    • pp.834-842
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    • 2011
  • Gelatin-based edible coating was used to reduce the oxidative degradation of low-fat sausages (LFSs) stored at $4^{\circ}C$ for 8 wk under vacuum packaging. The gelatin coating reduced thiobarbituric acid-reactive substances and peroxide value by 21.5 and 26.5%, respectively, compared with the controls. The moisture barrier effect was significantly better for the gelatin coating compared to the control. The gelatin coating reduced moisture loss in sausages by 32.6% over the control. However, the gelatin coating of sausages did not inhibit the growth of either the total plate counts or L. monocytogenes. Data show that gelatin can effectively be used as a natural antioxidative and moisture barrier coating to extend the quality and shelf life of sausages.

Slot-die Coating Method for Manufacturing Large-area Perovskite Solar Cell (대면적 페로브스카이트 태양전지 제작을 위한 슬롯-다이코팅 방법)

  • Oh, Ju-young;Ha, Jae-jun;Lee, Dong-geun
    • The Journal of the Korea Contents Association
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    • v.21 no.12
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    • pp.918-925
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    • 2021
  • The perovskite solar cell is a next-generation solar cell that replaces the existing silicon solar cell. It is a solar cell device using an organic-inorganic hybrid material having a perovskite structure as a photoactive layer. It has advantages for the process and has shown rapid efficiency improvement over the past decade. In the process of commercialization of such perovskite solar cells, research and development for a large-area coating method should be carried out. As one of the large-area perovskite solar cell large-area coating methods, the slot-die coating method was studied. By using a meniscus to pass over the substrate and coating the solution, the 3D printer was equipped with a meniscus so that it could be coated. Variables that act during coating include bed temperature, coating speed, N2 blowing interval, N2 blowing height, N2 blowing intensity, etc. By controlling these, the perovskite absorption layer was manufactured and the coating conditions for manufacturing large-area devices were optimized.

Breathable Waterproof Finish of PET Fabrics via Microporous UV Coating of Polyurethane Diacrylate (폴리우레탄 디아크릴레이트의 미세다공성 UV코팅에 의한 PET 직물의 투습방수가공)

  • Koo, Gwang-Hoe;Jang, Jin-Ho
    • Textile Coloration and Finishing
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    • v.22 no.3
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    • pp.239-245
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    • 2010
  • Breathable waterproof PET fabrics were prepared by the UV coating of UV-curable polyurethaneacrylate(PUA) formulation mixed with polyethyleneglycol(PEG) as a water soluble pore former. The dispersed PEG in the UV-cured coating was extracted by warm water, which can generate individual circular pores uniformly distributed all over the coating instead of pore channels. Accordingly the moisture permeability of the microporously coated fabrics increased substantially with increasing PEG addition without significant reduction of hydrostatic pressure. Also the silicone diacrylate addition in the formulation was beneficial in increasing the hydrostatic pressure. The UV-based microporous coating can be an alternative to conventional thermal curing of solventborne polyurethane coating owing to the enhanced environment friendliness and energy saving.

Tribological and Optical Characteristics of Silica Coating for Anti-reflection Coating of Solar Cell (태양전지의 반사방지막을 위한 Silica 코팅의 트라이볼로지 및 광학적 특성 평가)

  • Kim, Hae-Jin;Kim, Dae-Eun
    • Transactions of the Society of Information Storage Systems
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    • v.6 no.2
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    • pp.68-73
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    • 2010
  • The interest in acquiring high efficiency solar cells has been steadily increasing due to various advantages such as low-cost installation, pollution free and everlasting energy generation. In order to raise the cell efficiency, there has been a lot of effort to develop effective anti-reflection coatings. In this work, the main objective was to investigate the effects of particle size and annealing temperature of silica anti-reflection coatings to maximize the cell efficiency as well as reliability. It was shown that the light transmittance could be increased by a few percent over a certain range of wavelength using the silica coating. Also, the tribological properties of the coating could be improved through the annealing process, which led to better reliability of the coating.

Preparation and Dissolution Characteristics of A Gastro-Retentive Tablet System Containing Gabapentin (가바펜틴을 함유한 위체류성 정제의 제조 및 용출 평가)

  • You, Kwang-Hee;Lee, Pung-Sok;Oh, Eui-Chaul
    • Journal of Pharmaceutical Investigation
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    • v.39 no.4
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    • pp.269-273
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    • 2009
  • The objective of this investigation was to develop a gastro-retentive(GR) dosage form of gabapentin and was to evaluate of its dissolution characteristics. GR tablet consists of expandable core tablet matrix and semi-permeable membrane coating. Poloxamer 407 and sodium bicarbonate were used to prepare the core matrix. Polyvinly acetate dispersion (Kollicoat $SR30D^{(R)}$) and polyvinyl alcohol-polyethylene glycol copolymer ((Kollicoat $IR^{(R)}$)) were employed to form the semi-permeable membrane. The GR tablets significantly expanded up to fivefold in simulated gastrointestinal fluids with no apparent damage of the coating membrane over 12 hours. Also, the swelling rate was controllable with the amount of sodium bicarbonate. The drug release was observed to be substantially sustained based on coating level. The release rate of gabapentin from the GR tablet was gradually slowed down as the coasting amount was increased. The gabapentin GR tablet with 8% coating level showed a pseudo-zero order release kinetics over 12 hours. These results suggest that this swellable GR tablet system having semi-permeable membrane coating can be applicable for hydrophilic drug substances like gabapentin.

Estimation of Hardening Layer Depths in Laser Surface Hardening Processes Using Neural Networks (레이져 표면 경화 공정에서 신경회로망을 이용한 경화층 깊이 예측)

  • Woo, Hyun Gu;Cho, Hyung Suck;Han, You Hie
    • Journal of the Korean Society for Precision Engineering
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    • v.12 no.11
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    • pp.52-62
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    • 1995
  • In the laser surface hardening process the geometrical parameters, especially the depth, of the hardened layer are utilized to assess the integrity of the hardening layer quality. Monitoring of this geometrical parameter ofr on-line process control as well as for on-line quality evaluation, however, is an extremely difficult problem because the hardening layer is formed beneath a material surface. Moreover, the uncertainties in monitoring the depth can be raised by the inevitable use of a surface coating to enhance the processing efficiency and the insufficient knowledge on the effects of coating materials and its thicknesses. The paper describes the extimation results using neural network to estimate the hardening layer depth from measured surface temperanture and process variables (laser beam power and feeding velocity) under various situations. To evaluate the effec- tiveness of the measured temperature in estimating the harding layer depth, estimation was performed with or without temperature informations. Also to investigate the effects of coating thickness variations in the real industry situations, in which the coating thickness cannot be controlled uniform with good precision, estimation was done over only uniformly coated specimen or various thickness-coated specimens. A series of hardening experiments were performed to find the relationships between the hardening layer depth, temperature and process variables. The estimation results show the temperature informations greatly improve the estimation accuracy over various thickness-coated specimens.

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