• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.666-670
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• 2004

VLSI 소자에서 design rule(D/R)이 작아져 각 단위 Pattern의 size가 작아짐에 따라 aspect ratio가 커지게 되었다. 산화막 contact etch를 하는데 있어 산화막 측벽을 보호하는데, 이러한 보호막은 주로 fluoro-carbon 계열의 polymer precursor들이 사용된다. Aspect ratio(A/R)가 5 이하일 때에는 측벽의 보호막에 의한 바닥 변형이 문제가 되지 않으나, 10 이상의 A/R를 가진 contact에서는 크기가 줄고, 모양이 불균형하게 변하는 바닥 변형을 쉴게 관찰할 수 있다. 이러한 바닥 변형이 커지면 contact 저항이 높아지는 것은 물론이고, 심하게는 하부 pattern과 overlap 불량을 유발할 수 있다. 본 논문에서는 바닥변형을 일으키는 원인을 분석하고 fluoro-carbon 계열의 polymer precursor의 종류$(C_4_F6\;vs.\;C_3F_8)$에 따른 polymer증착 상태 확인 및 pattern비대칭에 따른 바닥 변형의 고찰과 plasma etching 시 H/W 변형을 통해 바닥 변형이 거의 없는 조건을 찾아낼 수 있었다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05b
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• pp.261-264
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• 2000

The purpose of this study is to research and develop solid polymer electrolyte(SPE) for Li polymer battery. This paper describes temperature dependence of conductivity, impedance spectroscopy, electrochemical properties of PAN/PVDF electrolytes as a function of a mixed ratio. PAN/PVDF based polymer electrolyte films were prepared by thermal gellification method of preweighed PAN/PVDF, plasticizer and Li salt. By adding PVDF and as a function of plasticizer mixed ratio to PAN-LiClO4 electrolyte, its conductivity was higher than that of PAN-$LiClO4_4$ electrolyte. The conductivity of PAN/PVDF electrolytes was $10^{-3}S/cm$. $10PAN10PVDFLiClO_4PC_5EC_5$ electrolyte shows the better conductivity of the others. Steady state current method and ac impedance used for the determination of transference numbers in PAN/PVDF electrolyte film. The transference number of $10PAN10PVDFLiClO_4PC_5EC_5$ electrolyte is 0.45.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.8
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• pp.645-649
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• 2009

We investigated the effects of a high density $O_2$ plasma treatment on the structural and electrical properties of Ga-, B- codoped ZnO (GZOB) films. The GZOB films were deposited on polymer substrate without substrate heating by DC magnetron sputtering. Prior to the GZOB film growth, we treated a polymer substrate with highly dense inductively coupled oxygen plasma. The optical transmittance of the GZOB film, about 80 %, was maintained regardless of the plasma pre-treatment. The resistivity of the GZOB film on PC substrate decreased from 9.08 ${\times}$ $10^{-3}$ ${\Omega}-cm$ without an $O_2$ plasma pre-treatment to 2.12 ${\times}$ $10^{-3}$ ${\Omega}-cm$ with an $O_2$ plasma pre-treatment. And PES substrate decreased from 1.14 ${\times}$ $10^{-2}$ ${\Omega}-cm$ without an $O_2$ plasma pre-treatment to 6.13 ${\times}$ $10^{-3}$ ${\Omega}-cm$ with an $O_2$ plasma pre-treatment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.295-295
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• 2008

Water tree experiments were done for several types of cross-linked polyethylenes. Test method is followed by ASTM D6097. Polyethylene is divided for four subgroup. First One is chemically cross-linked general XLPE, and second one is chemically cross-linked tree-retardant XLPE, and the third one is silane cross-linked polyethylene made by monosil process, and the last one is silane cross-linked polythylene made by copolymer. Tree retardant XLPE shows the shortest water tree length. Cahemcally cross-linked general XLPE shows the longest water tree length. Silane cross-linked polyethylene by copolymer is similar to tree retardant XLPE and similar breakdown strength. So silane cross-linked XLPE by copolymer could be used for the the medium voltage cable which should have tree retardant characteristics.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.2
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• pp.179-185
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• 2000

The purpose of this study was to develop an osteogenic, biodegradable material using polymer and BMP. It was designed to have structural function and be moldable, for the reconstruction of load bearing areas and deformities of various configurations. Bone apatite was added to Poly(L-lactide)(PLLA) and made porous for osteoconductability and ease of BMP loading. The materials, with or without BMP purified from porcine bone matrix, were evaluated in cranial bone defect models in rats for biocompatibility and bone regeneration capability. The following results were obtained: The PLLA-BMP material with BMP added to the polymer showed 30% healing of cranial bone defects in rats during the 2 weeks to 3 months period of observation. The moldable PLLA agent without BMP also showed 25% bone healing capacity. Although new bone formation was incomplete in the critical size defect of rat cranium, it can be concluded that the unique moldability of those agents makes them useful for the reconstruction of various bone defects and maxillofacial deformities.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.10
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• pp.1132-1141
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• 2004

The waveforms of the leakage currents for the surface discharge according to the degree of salt contamination and the variation of environmental condition on the EPDM polymer insulators, were shown in this paper. The variation phenomena of fundamental wave, 3rd and 5th harmonic waveforms were also shown from the beginning of the applied voltage and to the flashover voltage. To develop the technique of percentage contamination degree of EPDM polymer insulator according to the variation of environmental condition, the distortion degree of 3rd and 5th harmonic wave to the fundamental wave was utilized through the spectrum analysis for the waveforms of leakage current in the simulation of salt and fog test. The fact that distortion degree % of 3rd and 5th harmonics for fundamental wave is a necessary indicator for the assessment of contamination degree for the polymer insulators, was known.

• Tribology and Lubricants
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• v.21 no.4
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• pp.171-176
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• 2005

O-ring seal is an essential component in various mechanical apparatuses for a sealing of oil container and pressure vessels. This paper presents the sealing pressure and compressive contact behaviors of hi-polymer O-rings, which is made by an outer shell of FFKM material and an inner solid ring of FKM one. The contact normal pressure and its ratios are measured by experimental method with an automatic control system of the working temperature and analyzed numerically by using the non-linear Marc FEM program. The results show reasonably good agreements between the computed FEM results and measured ones when the operating temperature is kom normal temperature of $18^{\circ}C$ and a high temperature of $300^{\circ}C$ But the compared values between the computed and tested results show a little difference because of the increased temperature, which is related to the non-linear parameter of the O-ring material. Bi-polymer 0-ring shows a good contact normal stress and compression behavior for a given operation temperature and compression ratio.

• Journal of the Korean Wood Science and Technology
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• v.29 no.3
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• pp.59-67
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• 2001

Rice husk flours were analyzed by chemical composition and thermogravimetric methods in nitrogen atmosphere to discuss its feasibility as a raw material for manufacturing agricultural lignocellulosic fiber-thermoplastic polymer composite. It was revealed in the chemical composition analysis that rice husk flour was composed of moisture, 5.0%; lignin, 21.6%; holocellulose, 60.8%; ash, 12.6%. In the thermogravimetric analysis (TGA), thermal decomposition behavior of rice husk flour from room temperature to $350^{\circ}C$ was similar to that of wood flour, but rice husk flour was more thermally stable from 350 to $800^{\circ}C$ than wood flour because of higher silica content in the rice husk flour and smaller particle size of rice husk flour. The activation energy of thermal decomposition was evaluated using Flynn & Wall expression. As the thermal decomposition proceeded in rice husk flour, the activation energy of thermal decomposition appeared almost constant up to ${\alpha}=0.25$, but thereafter increased. Activation energy of thermal decomposition in wood flour, however, decreased steeply up to ${\alpha}=0.3$, but thereafter remained almost constant. From the results, rice husk flour was thought be a substitute for wood flour in manufacturing agricultural lignocellulosic fiber-thermoplastic polymer composite in the aspect of thermal decomposition.

• Transactions on Electrical and Electronic Materials
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• v.7 no.6
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• pp.283-292
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• 2006

So that high-strength and electrical properties apply by excellent high voltage insulator electricity material, ATH content and platinum-based flame retardant that influence in flame retardant and tracking characteristic among composite of silicone rubber studied mechanical strength and influence getting to electrical properties. Composition of ${\alpha}$, ${\omega}-vinyl$ poly (dimethyl-methylphenyl) siloxane(VPMPS) of a polymer quantity made doing mole of D4, $D3^{Me,Ph}$ and VMS by 1000:15:0.2 mole ratio and uses basic catalyst tetramethylammonium silanolate(TMAS) and do opening equilibrium polymerization to be used to main polymer for high voltage insulation insulator. Control ATH content and content of platinum-based flame retardant and made high voltage insulation silicone rubber. Measured mechanical strength of making silicone rubber using UTM, and tracking characteristic according to standard of IEC 60587, flame retardant test studied effect that flame retardant characteristic gets in tracking characteristic, measuring according to UL94V method of test.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.5
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• pp.436-442
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• 2009

This paper describes a study on the design of compact polymer bushing with inner control shield. In the bushing, a high electric stress occurred between field shaper and central conductor by the closely space. Also coaxial cylindrical shield has a great height along the axis to control an electric field. Consequently, all the potentials are raised axially along the field shaper and electric stress is concentrated on a part of the surface of the FRP tube near the upper end of the field shaper. In accordance, the field control can be achieved by means of the designs of such inner control shields. The floating and ring shield designs was decreased electric field concentration at critical parts of the bushing. The shield gaps is formed between field shaper and ring shield. Accordance equipotential lines extend through gaps. As a result, the resulting electrical stress are thus reduced in the range $17{\sim}23%$ in the bushing with floating and ring shield designs. Maxwell 2D simulator based on the boundary element method was also introduced in order to verify the reliability of the polymer bushing. The optimized design uses internal elements for electric stress grading at critical parts of the bushing.