• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1313-1316
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• 2005

In the present paper, it was investigated that adhesion layer on gate insulator could affect the electrical characteristics for the organic thin film transistors (OTFTs). The polyimide (PI) as organic adhesion layer was fabricated by using the vapor deposition polymerization (VDP) processing . It was found that electrical characteristics improved comparing OTFTs using adhesion layer to another. We researched adhesion layer as a function of thickness. For inverted-staggered top contact structure, field effect mobility, threshold voltage, and on-off current ratio of OTFTs using adhesion layer of PI 15 nm thickness on the gate insulator with a thickness of 0.2 ${\mu}m$ were about 0.5 $cm^2/Vs$, -0.8 V, and $10^6$, respectively.

• Journal of Electrical Engineering and Technology
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• 제7권1호
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• pp.91-96
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• 2012

We introduce an understanding of silver (Ag) inkjet overlap-printing characteristics from the viewpoints of cohesion between ink droplets and adhesion between an ink droplet and a surface. The printing characteristics were closely monitored by changing the surface energy to elucidate the effect of adhesion and cohesion on printing instability, such as droplet merging and line bulging. The surface energy of the substrate was changed through the hydrophilization of a hydrophobic fluorocarbon-coated surface. The surface energy and ink wettability of the prepared surfaces were characterized using sessile drop contact angle analysis, and printing instability was observed using an optical microscope after drop-on-demand inkjet printing with a 50% overlap in diameter of deposited singlet patterns. We found that the surface energy is not an appropriate indicator based on the experimental results of Ag ink printing on a hydrofluoric-treated silicon surface. The analytical approach using adhesion and cohesion was helpful in understanding the instability of the inkjet overlap-printing, as adhesion and cohesion represent the direct interfacial relationship between the Ag inks used and the substrate.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.958-961
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• 2007

The electrical characteristics of organic thin-filmtransistor (OTFTs) can be improved by inserting adhesion layer on gate dielectrics. Adhesion layer was used as polymeric adhesion layer deposited on inorganic gate insulators such as silicon dioxide $(SiO_2)$ and it was formed by vapor deposition polymerization (VDP) instead of spin-coating process. The OTFTs obtained the on/off ratio $of{\sim}10^4$, threshold voltage of 1.8V, subthreshold slop of 2.9 V/decade and field effect mobility about $0.01\;cm^2/Vs$.

• 한국전기전자재료학회논문지
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• 제19권4호
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• pp.357-361
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• 2006

The electrical performances of organic thin-film transistors (OTFTs) have been improved for the last decade. In this paper, it was demonstrated that the electrical characteristics of the organic thin film transistors (OTFTs) were improved by using polymeric material as adhesion layer on gate insulator. We have investigated OTFTs with polyimide adhesion layer which was fabricated by vapor deposition polymerization (VDP) processing and formed by co-deposition of 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride and 4,4'-oxydianiline. It was found that the OTFTs with adhesion layer showed better electrical characteristics than with bare layer because of good matching between semiconductor and gate insulator. Our devices of performance are field effect mobility of $0.4cm^2/Vs$, threshold voltage of -0.8 V and on-off current ratio of $10^6$. In addition, to improve the electrical characteristics of OTFT, we have reduced the thickness of adhesion layer up to a few nanometrs.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.70-71
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• 2005

The electrical performances of organic thin-film transistors (OTFTs) have been improved for the last decade. In this paper, it was demonstrated that the electrical characteristics of the organic thin film transistors (OTFTs) were improved by using polymeric material as adhesion layer on gate insulator. We have investigated OTFTs with polyimide adhesion layer which was fabricated by vapor deposition polymerization (VDP) processing and formed by co-deposition of 6FDA and ODA. It was found that the OTFTs with adhesion layer showed better electrical characteristics than with bare layer because of good matching between semiconductor and gate insulator. Our devices of performance are field effect mobility of $0.4cm^2$/Vs, threshold voltage of -0.8 V and on-of current ratio of $10^6$. In addition, to improve the electrical characteristics of OTFT, we have reduced the thickness of adhesion layer up to a few nanometrs.

• 대한기계학회논문집B
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• 제35권5호
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• pp.445-450
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• 2011

본 연구에서는 상압 플라즈마를 발생시켜 고분자 재료의 표면 자유에너지와 접착력의 변화를 조사하였다. 고분자 재질은 PC, PET, EVA 를 사용하였으며 표면자유에너지 변화를 관찰하기 위해 Di water 와 diiodomethane을 사용하여 접촉각을 측정하였다. 플라즈마 처리에 따른 접착력의 변화를 관찰하기 위해 PET 필름에 고분자 필름을 부착시켜 $180^{\circ}$ peel test 를 수행하였다. 그 결과 PET 필름의 표면자유에너지 및 접착력이 가장 큰 것을 확인할 수 있었으며, 상압 플라즈마 표면처리 공정은 필름 계면의 접착력을 크게 증가시켜 주는 것을 확인하였다.

• 한국산학기술학회논문지
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• 제7권2호
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• pp.150-156
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• 2006

전기철도차량의 성능특성을 향상시키기 위한 효과적인 방법중의 하나는 바퀴와 레일사이의 점착성능을 향상시키는 것이다. 점착특성을 연구하기 위해서 실제 차량을 등가 모델링한 점착시스템을 제작하였다. 이 시스템은 다양한 점착 파라미터를 변화시켜 바퀴와 레일사이의 점착력을 바꿀 수 있도록 제작되었다. 이 논문은 공전속도를 제어하는 기능을 추가하여 점착성능을 향상시키는 연구이다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.1455-1460
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• 2004

In electric motor coaches, when the adhesion force coefficient between rail and driving wheel decreases suddenly, the electric motor coach has slip phenomena. The characteristics of adhesion force coefficient is strongly affected by the conditions between rails and driving wheels, such as moisture, dust, and oil on the rails and so on. This paper proposes the vector control structure for the improved re-adhesion control with paralleled control of induction motors under the sudden variation of the adhesion force coefficient.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 D
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• pp.1879-1880
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• 2006

In electric motor coaches, when the adhesion force between rail and driving wheel decreases suddenly, the electric motor coach has slip phenomena. The characteristics of adhesion force coefficient is strongly affected by the conditions between rails and driving wheels, such as moisture, dust, and oil on the rails and so on. This paper proposes the simulation system for slip & slide test using virtual train. We can easily research the adhesion characteristics and adhesion control method with this equipment under the sudden variation of the adhesion force coefficient.

• 한국정밀공학회지
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• 제20권1호
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• pp.240-247
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• 2003

The tribological characteristics of FDTS (1H, 1H, 2H, 2H-Perflurodecyltrichlorosilane) SAM (self-assembled monolayer) and OTS (octadecyltrichlorosilane) SAM treated by high temperature annealing have been investigated from the viewpoint of stiction, adhesion and friction in micro/nano scale. From the experimental results, it was found that OTS SAM gets destroyed at 20$0^{\circ}C$ and stiction, adhesion and friction coefficient increased, but FDTS SAM was stable up to 40$0^{\circ}C$. Also, it was found that the friction coefficient of normal OTS SAM below 20$0^{\circ}C$ is lower than that of FDTS SAM in micro/nano scale, but stiction and adhesion is vice versa. This work shows the importance of surface group of self-assembled monolayer in dictating the tribological characteristics and thermal stability.