• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 춘계학술대회 논문집
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• pp.61-62
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• 2009

Electro-optical properties of liquid crystal display (LCD) using fringe-field switching (FFS) devices depend on many parameters such as cell retardation, electrode structure, magnitude and sign of dielectric anisotropy, rubbing angle and cell gap. In this paper, the light efficiency of FFS device depending on magnitude of positive dielectric anisotropy with other cell parameters such as rubbing angle and angle and cell gap have been explored compared with FFS device using LC with negative dielectric anisotropy.

• 한국정보전자통신기술학회논문지
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• 제16권1호
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• pp.8-17
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• 2023

기존 liquid crystal display(LCD) 공정에서 Indium Tin Oxide(ITO) 투명전극과 폴리이미드 배향막의 러빙 공정은 액정을 정렬하고 전계를 인가하기 위하여 필수적인 공정이다. 하지만 ITO의 증착은 높은 진공을 요구하며, 러빙 공정은 정전기에 의해 소자가 손상될 수 있는 단점이 존재한다. 본 논문에서는 기존 ITO 투명전극을 대체하기 위하여 PEDOT:PSS와 Multi-wall carbon nanotube(MWNT)를 혼합하여 PEDOT:PSS 나노복합체를 제조하고, 러빙 공정을 대체하기 위하여 나노 주름 구조 몰드를 통한 나노임프린팅을 통하여 박막을 형성함으로써 기존 액정 디스플레이의 투명전극과 배향막 두 가지 박막을 PEDOT:PSS/MWNT 나노복합체 박막 하나만으로 기능하게 하여 공정을 단순화 하였다. 전사된 나노 주름을 따라 액정이 잘 배향됨을 확인하였으며, 이를 기반으로 만들어진 액정 셀에서 박막 내 MWNT의 함량이 높아질수록 박막의 전기전도도가 증가하여 낮은 구동 전압과 빠른 응답 속도를 갖는다는 것을 확인하였다. 본 연구를 통해 공정 단순화와 용액공정에 의한 공정 단가 절감, 기존 러빙 공정의 단점을 해결하는데 기여 할 수 있을 것으로 기대된다.

• 한국전기전자재료학회논문지
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• 제16권6호
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• pp.510-514
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• 2003

We have studied the alignment of liquid crystals (LCs) on homeotropic polymeric surface that is scanned using an atomic force microscope (AFM) tip by optical polarizing microscopy and computer simulation. The scanned areas on one substrate are 5 $\mu\textrm{m}$ ${\times}$ 5 $\mu\textrm{m}$, 10 $\mu\textrm{m}$ ${\times}$ 10 $\mu\textrm{m}$, and 20 $\mu\textrm{m}$ ${\times}$ 20 $\mu\textrm{m}$ and this substrate is assembled to another substrate coated. with homeotropic polymer. The fabricated micro-LC cell using two substrates does not show any hysteresis and disclination lines inside the nano-rubbing areas, while changing voltage up and down. This indicates that the pretilt angle exists in the areas, thereby forming a hybrid LC configuration. From the experimental and computer simulation results, we can understand that the AFM rubbing clearly changes surface status of homeotropic alignment layer and causes the pretilt angle to an initial scanning direction.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 춘계학술대회 논문집
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• pp.21-24
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• 2008

Properties of carbon nano fiber (CNF) as field emitters were described. Carbon nano fiber (CNF) of herringbone was prepared by thermal chemical vapor deposition(CVD). Field emitters mixed with organic binders, conductive materials and were prepared by screen-printing process. In order to increase field emissions, the surface treatment of rubbing & peel-off was applied to the printed CNF emitters on cathode electrode. The measurements of field emission properties were carried out by using a diode structure inline vacuum chamber. CNF of herringbone type showed good emission properties that a turn on field was as low as 2.1 $V/{\mu}m$ and current density was as large as 0.15 $mA/cm^2$ of 4.2 $V/{\mu}m$ with electric field. Through the results. we propose that CNFs are suitable for application of electron emitters in Field Emission Devices.

• Elastomers and Composites
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• 제50권4호
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• pp.251-257
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• 2015

The rubber seal is a part inserted into servo cylinder to keep the air pressure constant. In order for efficient movements of the servo cylinder, the frictional coefficient of the rubber seal needs to be minimized while the sealing is maintained. In this work the friction characteristics of rubber seal specimen are tested on metal plate at various conditions. The experimental conditions include roughness level, applied pressure, lubrication, and rubbing speed. The design of experiment approach is taken to assess the effect of each parameter. The nonlinear frictional response of the rubber is applied to the FEM model simulating the servo cylinder movement. The result demonstrates that precise optimization of the servo cylinder movement must be preceded by preliminary experiments coupled with the theory and FEM model.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.76-79
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• 2003

The characteristic of single wall carbon nanotube (SW-CNT) and herringbone nano fiber (HB-CNF) emitters was described. SW-CNT synthesized by arc discharge and HB-CNF prepared by thermal CVD were mixed with binders and conductive materials, and then were formed by screen-printing process. In order to obtain efficient field emissions, the surface treatment of rubbing & peel-off was applied to the printed CNT and CNF emitters. The basic structure of FED was of a diode type through fully vacuum packaging. Also, we proposed a new triode type of field emitter using a mesh gate plate having tapered holes and could achieve the ideal triode properties with no gate leakage currents.

• 한국염색가공학회지
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• 제22권1호
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• pp.14-20
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• 2010

Squid ink was purified to melanin powder by repeated treatments with aqueous sodium hydroxide and acetic acid solutions. The exhaustion dyeing conditions of melanin to wool fabrics were investigated in relation with pH, melanin concentration, dyeing temperature and time. The melanin was dyeable to cotton and wool fabrics but higher dyeability of the wool was observed. A K/S of 7 was obtained on the optimally dyed wool fabrics with 5 % owf melanin under pH 4 at $100^{\circ}C$ for 60 minutes. Color fastness to both washing and rubbing was excellent and color fastness to light was also very good probably due to the polymeric nature of the extracted sepia melanin.

• 한국염색가공학회지
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• 제22권2호
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• pp.88-93
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• 2010

Using extracted sepia melanin powder by repeated treatments with aqueous sodium hydroxide and acetic acid solutions, vat dyeing of wool and cotton fabrics was carried out under various dyeing conditions including concentration of melanin, alkali, reducing agent and salt, as well as dyeing time and temperature. A K/S of 25.3 for wool fabrics was obtained at the optimal dyeing condition with 9% owf melanin, 0.5g/L NaOH and 56g/L $Na_2S_2O_4$ without salt at $80^{\circ}C$ for 90minutes. The vat dyeing of sepia melanin was applicable to both cotton and wool fabrics but the wool showed higher dyeability. The color fastness properties of the dyed wool and cotton fabrics were excellent to washing, rubbing and light irradiation.

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2009년도 제41차 학술발표회
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• pp.79-80
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• 2009

Aramid fabrics were photooxidized by UV/$O_3$ irradiation. The UV irradiation caused the oxygen content of the aramid fabric surface to increase and reduced the surface zeta potential, coupled with improved water wettability. The modified aramid fabrics showed higher affinity to cationic dyes which may be resultd from the newly introduced electrostatic interaction between cationic dyes and anionic dyeing sites on the photooxidized surface layers. Although color fastness to both staining and rubbing were good to excellent, color fastness to shade change was moderate.

• 패션비즈니스
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• 제16권2호
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• pp.138-150
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• 2012

Nano Inkjet DTP technology, a new technology introduced recently, can be applied to various types of fabric, and pre-treatment process can be omitted, which makes the whole printing process compact. Some important factors for DTP are color difference between the color selected by the designer on PC and the color on the final product and durability of the final fabrics. In this study, the twenty-three trend colors of 2012-2013 F/W suggested by PeclersParis have been picked to be printed on cotton, silk and polyester fabrics, then K/S and ${\Delta}E$ value and color fastness were measured. The results show that dyeability of fabric is varied for each color group, and that also tone of color affect to dyeability when measured for colors in the same group. In general, for all fabric, light fastness, washing fastness and color fastness to sublimation are outstanding. However, because of poor rubbing fastness, additional treatment to fix colorant on fabric is required.