• Membrane Journal
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• v.25 no.2
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• pp.123-131
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• 2015

The PTMSP/PDMS graft copolymer were synthesized from the PTMSP[poly(1-trimethylsilyl-1-propyne)] and the PDMS[poly(dimethylsiloxane)] and then the PTMSP/PDMS-borosilicate composite membranes were prepared by adding the porous borosilicates to the PTMSP/PDMS graft copolymer. The number-average molecular weight (${\bar{M}}_n$) and the weight-average molecular weight (${\bar{M}}_w$) of PTMSP/PDMS graft copolymer were 460,000 and 570,000 respectively, and glass transition temperature ($T_g$) of PTMSP/PDMS graft copolymer appeared at $33.53^{\circ}C$ according to DSC analysis. According to the TGA measurements, the addition of borosilicate to the PTMSP/PDMS graft copolymer leaded the decreased weight loss and the completed weight loss temperature went down. SEM observation showed that borosilicate was dispersed in the PTMSP/PDMS-borosilicate composite membranes with the size of $1{\sim}5{\mu}m$. Gas permeation experiment indicated that the addition of borosilicate to PTMSP/PDMS graft copolymer resulted in the increase in free volume, cavity and porosity resulting in the gradual shift of the mechanism of the gas permeation from solution diffusion to molecular sieving surface diffusion, and Knudsen diffusion. Consequently, the permeability of $H_2$ and $N_2$ increased and selectivity ($H_2/N_2$) decreased as the contents of borosilicate increased.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.194-197
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• 1997

The LB technique is one of the most powerful fabricating methods of organic ultra-thin film, which deposits a monolayer films in molecular level on the surface of the substrate. We have investigated the electrical characteristics of Myristic acid, Stearic acid and Arachidic acid LB films for horizontal direction to develop for the gas sensor. The optimum conditions for a film deposition were obtained by measurement of $\pi$-A isotherm. The status of the deposited film was confirmed by measurement of UV absorbance. We could distingished the difference of I-V characteristics for the fatty acid for the horizontal direction. The conductivity of fatty acid LB films for horizontal direction was 10$^{-7}$ ~ 10$^{-9}$ [S/cm] that mean like semiconductor.

• Electrical & Electronic Materials
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• v.5 no.4
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• pp.411-420
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• 1992

C$_{2+}$-Quinolium(TCNQ) 유기 초박막을 Langmuir-Blodgett 방법을 이용하여 유리기판 위에 누적하였다. 이의 최적 누적조건을 알아보기 위하여 .pi.-A isotherm특성을 온도, pH, 압축 속도, 분산량 등을 변화시키면서 조사하였다. 누적 과정은 전이비를 통하여 고체 기판에 누적되는 정도를 살펴볼 수 있었으며 누적된 박막은 다음과 같은 방법으로 확인하였다. 광학적인 방법으로 광흡수도, 전기적인 방법으로 전기 용량, 그리고 기계적인 방법으로 두께를 직접 측정하여 누적된 박막의 상태를 관찰하였다. 상온에서 이방성 전기 전도도를 측정하였는데 수평 방향으로 ~1 x $10^{-7}$S/cm, 수직 방향으로 ~1 x $10^{-14}$S/cm의 값을 얻었다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.11a
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• pp.393-396
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• 1996

The electrical characteristics of stearic acid LB films far the horizontal direction were investigated to develop the gab sensor using LB films. $\pi$ -A isotherm was measured to transfer stearic acid on slide glass substrate and surface pressure for optimal deposition was 25[dyne/cm]. The deposition status of stearic acid LB films was verified by the measurement of capacitance which was increased with the number of layers. The thickness of electrode was estimated about 1000 by the I-V characteristics far the horizontal direction. The Conductivity of stearic acid LB films for horizontal direction was 10$^{-8}$ [S/cm] that mean like semiconductor.

• Proceedings of the Korean Information Science Society Conference
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• 2004.10a
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• pp.496-498
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• 2004

무선 ad-hoc 네트워크는 이동 노드만으로 구성된 자율적이고 수평적인 네트워크이다. 무선 ad-hoc 네트워크에서의 라우팅 프로토콜은 table driven 방식과 on-demand 방식으로 나뉘는데, 이 중 라우팅 메시지의 오버헤드가 비교적 적은 on-demand 방식이 주로 사용되고 있다. 이 프로토콜은 경로를 찾기 위해서 경로 요청 메시지를 브로드캐스팅 하는데, 경로 요청 메시지는 네트워크 전체로 확산되기 때문에 이를 이용한 공격이 가능하다 공격자는 연속적으로 경로 요청 메시지를 보냄으로써 패킷 충돌과 네트워크 큐오버플로우 등의 장애를 일으켜 정상적인 메시지나 데이터의 전송을 방해할 수 있다. 본 논문에서는 기존의 라우팅 프로토콜에 별도의 인증 절차 없이 경로 요청 패킷의 확산을 이용한 공격을 막는 방법을 제안하고자 한다. 각각의 노드는 경로 요청 메시지의 시작 주소와 수신 시간을 경로 요청 테이블을 이용해 관리함으로써 정상적인 경로 요청 패킷과 공격자의 경로 요청 패킷을 구분한다. 수신된 경로 요청 패킷이 공격자의 패킷이라고 판단된 경우, 공격자의 패킷을 이웃 노드에 전달하지 않음으로써 전체 네트워크에 가해지는 공격을 막을 수 있다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.449-450
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• 2005

Alignment characteristic of liquid crystal (LC) on in-cell retarder which is composed of reactive mesogens has been tested. The in-cell retarder which is polymerized on top of the homogeneous alignment layer (AL) has an optic axis along the rubbing direction of the homeogenous AL and does show good alignment effect of the LC without showing any defects, which possibly allows a skip of another AL on the in-cell retarder that was required conventionally to control alignment of the LC. However, the measured pretilt angle is only 0.04 degree so that disclination lines are generated for a cell that uses the in-cell retarder as an AL when the LC is tilted upward by a vertical electric field.

• Journal of the Korean Magnetics Society
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• v.4 no.3
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• pp.239-243
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• 1994

$NiFe/TbCo/Si_3N_4$ thin films were fabricated, which can be employed as dualOongitudinal and transverse) biased magnetoresistive elements utilizing surface magnetic exchange at the interface of NiFe/TbCo films. When Tb area percent was 36 % and substrate bias was not applied, magnetic exchange fields of 100~180 Oe were obtained. The thicknesses of NiFe, TbCo and $Si_3N_4$(Protective layer) were $470\;{\AA},\;2400\;{\AA}\;and\;600\;{\AA}$, respectively. Magnetoresistance ratio of 1.45 % was obtained using NiFe films fabricated with 1000 W power and 2.5 mTorr of Ar pressure. The MR ratio of microstructured elements was reduced to 1.31 % and the MR response curves were shown not to saturate due to demagnetizing fields of the elements. When elements were fabricated with $36^{\circ}$ of misalignment with respect to the exchange field direction using films having 150 Oe exchange field, MR response curve was shifted by 85 Oe, and the operating point of the device shifted to the linear region of the response. Also, the Barkhausen noise was eiminated due to longitudinal bias field originating from the exchange field.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2008.11a
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• pp.18-18
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• 2008

3차원 패키징 System In Package (SIP)구조에서 Chip to Chip 단위 Interconnection 역할을 하는 Through Silicon Via(TSV)를 형성하기 위하여 Pulsating RF bias가 장착된 Inductively Coupled Plasma Etcher 장비를 이용하였다. 이 Pulsating 플라즈마 공정 방법은 주기적인 펄스($50{\sim}500Hz$)와 듀티($20{\sim}99%$) cycle 조절이 가능하며, 플라즈마 에칭특성에 영향을 주는 플라즈마즈마 발생 On/Off타임을 조절할 수 있다. 예를 들면, 플라즈마 발생 Off일 경우에는 이온(SFx+, O+)과 래디컬(SF*, F*, O*)의 농도 및 활성도를 급격하게 줄이는 효과를 얻을 수가 있는데, 이러한 효과는 식각 에칭시, 이온폭격의 손상을 급격하게 줄일 수 있으며, 실리콘 표면과 래디컬의 화학적 반응을 조절하여 에칭 측벽 식각 보호막 (SiOxFy : Silicon- Oxy- Fluoride)을 형성하는데 영향을 미친다. 그리고, TSV 형성에 있어서 큰 문제점으로 지적되고 있는 언더컷과 수평에칭 (Horizontal etching)을 개선하기 위한 방법으로, Black-Siphenomenon을 이번 실험에 적용하였다. 이 Black-Si phenomenon은 Bare Si샘플을 이용하여, 언더컷(Undercut) 및 수평 에칭 (Horizontal etching)이 최소화 되는 공정 조건을 간편하게 평가 할 수 있는 방법으로써, 에칭 조건 및 비율을 최적화하는 데 효율적이었다. 결과적으로, Pulsating RF bias가 장착된 Inductively Coupled Plasma Etcher 장비를 이용한 에칭실험은 펄스 주파수($50{\sim}500Hz$)와 듀티($20{\sim}99%$) cycle 조절이 가능하여, 이온(SFx+, O+)과 래디컬(SF*, F*, O*)의 농도와 활성화를 조절 하는데 효과적이었으며, Through Silicon Via (TSV)를 형성 하는데 있어서 Black-Si phenomenon 적용은 기존의 Continuous 플라즈마 식각 결과보다 향상된 에칭 조건 및 에칭 프로파일 결과를 얻는데 효과적이었다.

• Applied Chemistry for Engineering
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• v.10 no.2
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• pp.225-230
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• 1999

Low pressure metal organic chemical vapor deposition (LPMOCVD) of $Li_2O$ solid thin films from Li(DPM) in nitrogen-oxygen or argon-oxygen atmosphere was experimentally investigated by using a small hot wall tubular type reactor. XRD and ESCA analysis revealed that $Li_2CO_3$ film grew in nitrogen-oxygen atmosphere and $Li_2O$ grew in argon-oxygen atmosphere. The grown lithium oxide or carbonate reacted with silicon or silica base materials to produce silicates. The CVD model analysis by means of the well-known micro trench method and Monte Carlo simulation was not fully successful, but a set of data on gas phase reaction rate constant and surface reaction constant was obtained.

• Journal of IKEEE
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• v.23 no.3
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• pp.904-909
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• 2019

Using the ion-beam irradiated indium zinc oxide (IZO) films which was cured at $100^{\circ}C$, uniform LC and homogeneous alignment of liquid crystal (LC) molecules was achieved. The IZO film was deposited on the glass substrate at the curing temperature of $100^{\circ}C$ and irradiated by the ion-beam which is an LC alignment method. To verify the LC alignment characteristics, polarizing optical microscope and the crystal rotation method were used. Additionally, it was confirmed that the LC cell with the IZO films had an enough thermal budget for high-quality LC applications. Field emission scanning electron microscope was conducted as a surface analysis to evaluate the effect of the ion-beam irradiation on the IZO films. Through this, it was revealed that the ion-beam irradiation induced rough surface with anisotropic characteristics. Finally, electro-optical (EO) performances of the twisted-nematic cells with the IZO films were collected and it was confirmed that this cell had better EO performances than the conventional rubbed polyimide. Furthermore, the polar anchoring energy was measured and a suitable value for stable LC device operation was achieved.