• 열처리공학회지
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• 제34권3호
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• pp.107-115
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• 2021

Al-Si coated boron steel has been widely used as commercial hot stamping steel. When the steel is heated at 900~930℃ for 5 min in an electric furnace, thickness of the coating layer increases as a consequence of formation of intermetallic compounds and diffusion layer. The diffusion layer plays an important roll in blunting the propagation of crack from coating layer to base steel. Change in microstructure and coating layer of Al-Si coated boron steel after conductive heating with higher heating rate than electric furnace has been investigated in this study. Conductive-heated steel showed the martensitic structure with vickers hardness of 505~567. Both intermetallic compounds in coating layer and diffusion layer were not observed in conductive-heated steel due to rapid heating. It has been found that the conductive-heating consisting of rapid heating to 550℃ which is lower than melting point of Al-Si coating layer, slower heating to 900℃, and then 1 min holding at 900℃ is effective in forming intermetallic compound in coating layer and diffusion layer.

• Current Photovoltaic Research
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• 제4권4호
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• pp.140-144
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• 2016

In this paper, core-shell structure of nickel/gold (Ni/Au) conductive layer on poly-methyl-methacrylate (PMMA) micro-ball was fabricated and its conduction property was investigated. Firstly, PMMA micro-ball was synthesized by using dispersion polymerization method. Size of the ball was $2.8{\mu}m$ within ${\pm}7%$ deviation, and appropriate elastic deformation of the PMMA micro-ball ranging from 31 to 39% was achieved under 3 kg pressure. Also, 200 nm thick Ni/Au conductive layer was fabricated on the PMMA micro-ball by uniformly depositing with electroless-plating. Adhesion of the conductive layer was optimized with help of surface pre-treatment, and the layer adhered without peeling-off despite of thermal expansion by collision with accelerated electrons. Composite paste containing core-shell structured particles well cured at low temperature of $130^{\circ}C$ while pressing the test chip onto the substrate to make electrical contact, and electrical resistance of the conductive layer showed stable behavior of about $6.0{\Omega}$. Thus, it was known that core-shell structured particle of the Ni/Au conductive layer on PMMA micro-ball was feasible to flexible electronics.

• 한국표면공학회지
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• 제46권4호
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• pp.162-167
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• 2013

Encapsulation is required since organic materials used in OLED devices are fragile to water vapor and oxygen. Laser sealing method is currently used where IR laser is scanned along the glass-frit coated lines. Laser method is, however, not suitable to encapsulating large-sized glass substrate due to the nature of sequential scanning. In this work we propose a new method of encapsulation using Joule heating. Conductive layer is patterned along the sealing lines on which the glass frit is screen printed and sintered. Electric field is then applied to the conductive layer resulting in bonding both the panel glass and the encapsulation glass by melting glass-frit. In order to obtain uniform bonding the temperature of a conductive layer having a shape of closed loop should be uniform. In this work we conducted simulation for heat distribution according to the structure of a conductive layer used as a Joule-heat source. Uniform temperature was obtained with an error of 5% by optimizing the structure of a conductive layer. Based on the results of thermal simulations we concluded that Joule-heating induced encapsulation would be a good candidate for encapsulation method especially for large area glass substrate.

• 지구물리와물리탐사
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• 제17권1호
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• pp.28-33
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• 2014

최근 제주도 서부 중산간(해발고도 400 ~ 900 m) 지역에서 획득된 자기지전류(MT) 탐사자료와 제주도 중산간 전역에서 획득되었던 기존 MT 탐사 자료의 1차원 역산을 통하여 서귀포층과 U층으로 대표되는 퇴적층에 해당하는 저비 저항층의 분포형태를 살펴보았다. 저비저항층의 상부경계는 제주도 표고와 매우 높은 양의 상관관계를 가지고 있으며 하부경계는 표고와 음의 상관관계를 가진다. 즉, 저비저항층은 제주도 중앙부에서 두꺼운 렌즈 형태를 하고 있으며 그 하부의 기반암은 중앙부에서 오목한 형태일 가능성이 높다. 이러한 표고와의 상관성을 고려하는 크리깅을 수행하여 제주도의 지전기 구조 모델을 제시하였다. 하지만 한라산의 화도를 따라 3차원 형태의 저비저항 이상체가 존재할 가능성과 시추공 자료와의 차이를 발생시키는 원인을 규명하기 위하여 3차원 모델링과 다른 지구물리탐사나 물리검층 자료와의 복합해석이 요구된다.

• 한국재료학회지
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• 제25권3호
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• pp.132-137
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• 2015

The effects of the mixing of an active material and a conductive additive on the electrochemical performance of an electric double layer capacitor (EDLC) electrode were investigated. Coin-type EDLC cells with an organic electrolyte were fabricated using the electrode samples with different ball-milling times for the mixing of an active material and a conductive additive. The ball-milling time had a strong influence on the electrochemical performance of the EDLC electrode. The homogeneous mixing of the active material and the conductive additive by ball-milling was very important to obtain an efficient EDLC electrode. However, an EDLC electrode with an excessive ball-milling time displayed low electrical conductivity due to the characteristic change of a conductive additive, leading to poor electrochemical performance. The mixing of an active material and a conductive additive played a crucial role in determining the electrochemical performance of EDLC electrode. The optimal ball-milling time contributed to a homogeneous mixing of an active material and a conductive additive, leading to good electrochemical performance of the EDLC electrode.

• 대한금속재료학회지
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• 제48권1호
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• pp.90-100
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• 2010

Micro-conductive patterns were microfabricated on an insulating substrate ($SiO_2$) surface by a selective electroless nickel plating process in order to investigate the formation of seed layers. To fabricate micro-conductive patterns, a thin layer of metal (Cu.Cr) was deposited in the desired micropattern using laser-induced forward transfer (LIFT). and above this layer, a second layer was plated by selective electroless plating. The LIFT process. which was carried out in multi-scan mode, was used to fabricate micro-conductive patterns via electroless nickel plating. This method helps to improve the deposition process for forming seed patterns on the insulating substrate surface and the electrical conductivity of the resulting patterns. This study analyzes the effect of seed pattern formation by LIFT and key parameters in electroless nickel plating during micro-conductive pattern fabrication. The effects of the process variables on the cross-sectional shape and surface quality of the deposited patterns are examined using field emission scanning electron microscopy (FE-SEM) and an optical microscope.

• Journal of Industrial and Engineering Chemistry
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• 제68권
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• pp.387-392
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• 2018

Various technical approaches and concepts have been proposed to develop conductive super-hydrophobic (SH) surfaces. However, most of these approaches are not usable in practical applications because of insufficient adhesion and cost issues. Additionally, durability and uniformity issues are still in need of improvement. The goal of this research is to produce a large-area conductive SH surface with improved adhesion performance and uniformity. To this end, carbon nanotubes (CNT) with a high aspect ratio and elastomeric polymer were utilized as a conductive filler and matrix, respectively, to form a coating layer. Additionally, nanoscale silica particles were utilized for stable implementation of the conductive SH surface. To improve the adhesion properties between the SH coating layer and substrate, pretreatment of the substrate was conducted by utilizing both wet and dry etching processes to create specific organic functional groups on the substrate. Following pretreatment of the surface, a zirco-aluminate coupling agent was utilized to enhance adhesion properties between the substrate and the SH coating layer. Raman spectroscopy revealed that adhesion was greatly improved by the formation of a chemical bond between the substrate and the SH coating layer at an optimal coupling agent concentration. The developed conductive SH coating attained a high electromagnetic interference (EMI) shielding effectiveness, which is advantageous in self-cleaning EMI shielding applications.

• 한국소음진동공학회논문집
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• 제18권12호
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• pp.1310-1316
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• 2008

Bi-layer and tri-layer structures of electro-active paper(EAPap) using conductive polyaniline(PANI) coating were investigated to improve bending displacement of cellulose EAPap. Two different counter ions, perchlorate($CIO_4^-$) and tetrafluoroborate($BF_4^-$), are used as dopant ions in the PANI processing. The actuation performances of hi-layer and tri-layer structure are evaluated in terms of tip displacement, blocked force, strain energy density and power output density. The actuation performance of the tri-layer actuator was better than the hi-layer structure, and the maximum displacement and blocked force of tri-layer $CIO_4^-$ doped-PANI-EAPap were 13.2 mm and 0.15 mN, respectively. Also the power output of the actuator is similar to the required power of biological muscle application.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2007년도 춘계학술대회 논문집
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• pp.3-6
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• 2007

The Light brightness is to enhance the luminescence efficiency of phosphor including conductive material. In preparing the anode layer, phosphors mixed with conductive material prepared with pastes of polymer resin using by screen printing method. When the prepared anode layer bombarded by cold electron from emitter of cathode, it give rise to form the secondary electron from those of conductive materials such as ITO powder. Furthermore, we are expect to enhance the luminescence efficiency more than without conductive material.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제51권3호
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• pp.125-133
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• 2002

In order to fabricate stable conductive polymer actuators which can be operated in air, conductivity and solidity of polymer electrolyte materials have been studied. It was found that Nafion+LiCl is appropriate material to be used for conductive polymer actuator. Using the Nafion+LiCl solid polymer electrolyte, single layer PPy actuators have been fabricated and their deflection was measured. Double layer PPy actuators make up for shortcoming of single layer PPy actuator and displacement and frequency response can be improved by fabrication of double layer PPy actuator. This kind of all-solid-polymer actuator can be used for practical applications.