• Journal of the Korean Vacuum Society
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• v.9 no.4
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• pp.394-399
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• 2000

The effects of the type and thickness of underlayer on the crystallographic texture and the sheet resistance of aluminum thin film were studied. Ti and Ti/TiN were examined as the underlayer of aluminum. Ti and TiN were prepared by ionized physical vapor deposition (I-PVD) metalorganic chemical vapor deposition (MOCVD), respectively. The texture and the sheet resistance of metal thin film stacks were investigated at various thicknesses of Ti or TiN, and the sheet resistance was measured after annealing at $400^{\circ}C$ in an nitrogen ambient. For I-PVD Ti underlayer, the excellent texture of aluminum <111> was obtained even at top of 5 nm of Ti. However, the sheet resistance of the metal stack was greatly increased after annealing due to the interdiffusion and reaction of Al and Ti. MOCVD TiN between Ti and Al could suppress the Al-Ti reaction without severe degradation of aluminum <111> texture. Excellent texture of aluminum was obtained for the MOCVD TiN thinner than 4 nm.

• Journal of the Korean Ceramic Society
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• v.39 no.5
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• pp.517-522
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• 2002

In this study, the effect of the processing parameters in PVD process on the size and the distribution of deposited Si quantum dots was quantitatively investigated by computational simulation utilizing Monte Carlo method. The processing parameters, substrate temperature, deposition time, gas pressure and target-substrate distance were selected as variables since those parameters are often selected as variables in PVD experiments. It is predicted that the density of $1{\times}10^{12}cm^{-2}$ Si quantum dots can be deposited on the substrate when the deposition rate is 0.05 nm/sec at the substrate temperature of 490${\circ}$, deposition time of 7 sec, gas pressure of 3 mTorr and target-substrate distance of 8 cm.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.193.2-193.2
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• 2014

열차폐 코팅(Thermal Barrier Coating)은 주로 항공기 엔진이나 화력발전용 터빈 등의 $1300^{\circ}C$ 이상의 고온에서 사용되는 부품에 적용되어 모재(내열합금)의 손상 방지 및 에너지 효율 향상을 위해 사용되고 있다. 열차폐 코팅의 경우 Plasma Spray 공법과 EB-PVD(전자빔 물리 증착법) 공법이 가장 많이 사용되고 있다. Plasma Spray에 의한 열차폐 코팅 공정은 생산 비용이 저렴하고 수평형 적층 구조를 통한 높은 열전도율을 가지는 장점이 있으며, EB-PVD 공정은 수직형 구조의 열차폐막을 통해 내열 충격성과 내열 사이클성이 양호하다는 장점이 있다. 본 연구에서는 열 사이클의 내구성이 뛰어난EB-PVD를 이용하여 열차폐 코팅 공정연구를 진행하였다. 본 연구소에서 사용하고 있는 EB-PVD 는 종래의 장치와는 달리 70 kW급 전자총 5기가 장착 되어 있으며, 각각 시편 가열용 전자총 2기 및 피코팅용 가열 전자총 3기로 구성되어 있다. 이런 구성을 통해 다양한 종류의 열차폐 박막과 높은 결정성과 치밀도를 가지는 박막 형성할 수 있을 것이다. 본 발표에서는 EB-PVD 공정 연구결과 및 향후 실용화를 위한 개발 연구 방향에 대해서 기술하였다.

• Journal of Broadcast Engineering
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• v.22 no.3
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• pp.350-365
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• 2017

Steganography is a technique for secret data communication, which is not perceived by third person between a receiver and a transmitter. It has been developed for thousands of years for the transmission of military, diplomatic or business information. The development of digital media and communication has led to the development of steganography techniques in modern times. Technic of image steganography include the LSB, which fixes the number of embedded bits into a pixel, and PVD, which exploits the difference value in the neighboring pixel pairs. In the case of PVD image steganography, a large amount of information is embedded fluidly by difference value in neighboring pixel pairs and the designed range table. However, since the secret information in order is embedded, if an error of the number of embedded bits occurs in a certain pixel pair, all subsequent information will be destroyed. In this paper, we proposes the method, which improve the vulnerability of PVD property about external attack or various noise and extract secret information. Experimental process is comparison analysis about stego-image, which embedded various noise. PVD shows that it is not possible to preserve secret information at all about noise, but it was possible to robustly extract secret information for partial noise of stego-image in case of the proposed PVD image steganography with locally-fixed number of embedding bits.

• Journal of the Korean Vacuum Society
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• v.4 no.S1
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• pp.21-27
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• 1995

AI planarization 공정을 위한 barrier로서 CVD 및 PVD 방법에 의해 증착된 TiN 박막의 특성에 대하여 연구하였다. CVD TiN은 TDMAT source를 사용한 MOCVD방법으로 증착하였으며, PVD TiN은 1:1 aspect ratio(A/R)를 갖는 collimator를 사용한 reactive wputtering법으로 증착하였다. AES, SEM을 이용하여 CVD TiN과 PVD TiN의 조성을 분석하고 barrier 특성을 평가하였다. CVD TiN, PVD TiN 모두 400$\AA$의 두께와 RTA 처리에 의해서 AI planarization에 대한 양호한 barrier 특성을 확보할 수 있었다.

• Proceedings of the Safety Management and Science Conference
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• 2001.11a
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• pp.157-160
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• 2001

The electrodes were fabricated by compounding the commercial activated carbons and additives of conducting polymer with PVdF mono binder and PVdF-PVP mixed binders. The best performance of the electrodes fabricated with activated carbon(BP-20) and PVdF-PVP mixed binders showed in 88wt. ％ BP-20. 7wt. ％ conducting polymer and 5wt.％ PVdF-PVP mixed binder. The electrode exhibited excellent electrochemical characteristics having 8.16 W.h/kg of energy density, 34.77 F/g of specific capacitance, $0.67\Omega$of ESR.

• Journal of the Korean Ceramic Society
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• v.42 no.2 s.273
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• pp.117-122
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• 2005

Electron Beam Physical Vapor Deposition (EB-PVD) is a typical technology for thermal barrier coating with Yttria Stabilized Zirconia (YSZ) on aero gas turbine engine. In this study EB-PVD method was used to fabricate dense YSZ film on NiO-YSZ as a electrolyte of Solid Oxide Fuel Cell (SOFC). Dense YSZ films of -10 $\mu$m thickness showed nano surface structure depending on deposition temperature. Electrical conductivities of YSZ film and electric power density of the single cell were evaluated after screen- printing $LaSrCoO_3$ as a cathode.

• Polymer(Korea)
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• v.24 no.3
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• pp.382-388
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• 2000

Polymer electrolyte films consisting of poly(vinylidenefluoride-hexafluoropropylene) (PVdF-HFP), LiClO$_3$ and a mixture of ethylene carbonate (EC) and ${\gamma}$-butyrolactone (GBL) were examined in order to obtain the best compromise between high ionic conductivity, homogeniety, dimensional and electrochemical stability. Measurements of ionic conductivity, differential scanning calorimetry and linear sweep voltammetry have been carried out for various compositions. The highest conductivity of 3.8$\times$10$^{-3}$ S$cm^{-1}$ / at 3$0^{\circ}C$ were obtained for a film of 30(PVdF-HFP)+7.8LiClO$_4$+62.2EC/GBL. From the DSC study, it has been found that the PVdF-HFP gels are stable up to 10$0^{\circ}C$, and the salt lowers the melting temperature of crystalline part of PVdF by interacting sensitively with polymer segments. When Lithium metal is in contact with the gel films, it tends to undergo corrosion and the reaction products accumulate resulting in the formation of a passive film on Li electrode. As the aging time progresses, the interfacial resistance increases continuously. Anodic stability is measured to extend up to about 4.5 V vs. Li.

• Membrane Journal
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• v.16 no.4
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• pp.286-293
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• 2006

Porous asymmetric membranes based on PVdF as a nascent membrane were prepared by using a phase inversion method. PVdF ion conductive composite membranes were finally made by introducing $SO_3{^-}$ from sulfuric acid after cross-linked PS with various DVB contents in the pores of PVdF. Final PVdF composite membranes were characterized by FTIR, SEM, EDS to verify $SO_3{^-}$. It was revealed that the solvent contents and ion exchange capacity (IEC) decreased with increase of the degree of cross-linking. As the degree of crosslink increases both the electric conductivity and methanol permeability decreased, which was showing the better values than Nafion 117. When DVB content was 8%, its electric conductivity ($5.58{\times}10^{-5}S/cm$) was similar to Nafion 117 ($6.03{\times}10^{-5}S/cm$). But the lower methanol permeability ($1.0{\times}10^{-6}cm^2/sec$) than that of Nafion 117 was obtained.

• Applied Chemistry for Engineering
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• v.33 no.3
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• pp.289-295
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• 2022

In this study, we intend to fabricate an all solid polymer battery with a reduced interfacial resistance between the solid electrolyte and the electrode by applying thiophene based polymers as both electrode and electrolyte materials. In order to minimize the interfacial resistance with the poly(3,4-ethylenedioxy thiophene) (PEDOT) based electrode, 3,4-ethylenedioxy thiophene (EDOT) oligomer was introduced into the solid electrolyte. Also, to improve the lithium salt dissociation ability of the EDOT oligomer [oligo(EDOT)] electrolyte, it was blended with poly(vinylidene fluoride) (PVdF). As a result, the ionic conductivity of the solid polymer electrolyte increased by introducing PVdF into the oligo (EDOT). From the result of evaluating the electrochemical properties of an all solid polymer battery, the interfacial resistance significantly decreased by introducing a thiophene based polymer to the electrode and electrolyte.