• Electrical & Electronic Materials
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• v.10 no.10
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• pp.983-988
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• 1997

We investigated the structural and dielectric properties of PZT(20/80)/PZT(80/20) heterolayered thin films that fabricated by the alkoxide-based Sol-Gel method. PZT(20/80)/PZT(80/20) heterolayered thin films were spin-coated on the Pt/Ti/SiO$_2$/Si substrate with PZT(20/80) film of tetragonal structure and PZT(80/20) film of rhombohedral structure by turns. Each layers were dried to remove the organic materials at 30$0^{\circ}C$ for 30min and sintered at $650^{\circ}C$ for 1hr. This procedure was repeated several times to form PZT(20/80)/PZT(80/20) heterolayered films and thickness of the film obtained by one-times of drying/sintering process was approximately 80-90nm. PZt-1, 3, 5 films with top layer of PZT(20/80) film of tetragonal structure showed fine grain structure and PZT-2, 4, 6 films with top layer of PZT(80/20) film of rhombohedral structure showed the dense grain microstructure without rosette-type. Dielectric constant and dielectric loss of the PZT-6 film were approximaterly 1385 and 3.3% respectively. Increasing the number of coatings remanent polarization was increased and coercive field was decreased and the values of the PZT-6 film were 8.13$\mu$C/cm$^2$and 12.5kV/cm respectively.

• Electrical & Electronic Materials
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• v.10 no.6
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• pp.541-547
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• 1997

(Pb$_{1-x}$ La$_{x}$)Ti$_{1-x}$ $_4$O$_3$(x=0, 0.02, 0.04, 0.08) ceramic thin films were fabricated by Sol-Gel method. A stock solution of (Pb, La)TiO$_3$ with excess Pb 10 mol% was made and spin-coated on the Pt/Ti/SiO$_2$/Si substrate at 400rpm for 30 seconds. Coated specimens were dried on the hot-plate at 35$0^{\circ}C$ for 10 min and sintered at 500~75$0^{\circ}C$ for 1 hour. The dielectric constant, remanent polarization and coercive field of the PLT(6at.%) thin films sintered at $650^{\circ}C$ were 884, 13.95$\mu$C/$\textrm{cm}^2$ and 8.7kV/cm, respectively. Pyroelectric coefficient, figure of merit of pyroelectric current, voltage responsivity and detectivity of PLT(6at.%) thin films were 3.2$\times$10$^{-8}$ C/$\textrm{cm}^2$K, 1.02$\times$10$^{-8}$ C.cm/J, 2.9 $\times$10$^{-11}$ C.cm/J, 0.29$\times$10$^{-8}$ C.cm/J, respectively.ely.

• Electrical & Electronic Materials
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• v.9 no.7
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• pp.668-673
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• 1996

In this paper, (P $b_{1-x}$ L $a_{x}$)(Z $r_{0.52}$ $Ti_{0.48}$) $O_{3}$ (X=0-13[at%]) thin film were prepared by the Sol-Gel method, Multiple PLZT thin films were spin-coated on the Pt/Ti/ $SiO_{2}$Si substrate. The electrical properties of the films were investigated for varying the annealing temperature. In the PLZT(11/52/48) specimens, the dielectric ocnstant of 1236 and the polarization reversal time of 460[nm] were obtained and the breakdown of the film did not occur up to 1*10$^{10}$ cycles at the voltage of 7[V] by the bipolar acceleration. The remanent polarization and coercive field decreased with increasing the content of La in the range of 0-13[at%] and thin film of the PLZT(11/52/48) showed the value of 2.56[.mu.C/c $m^{2}$] and 21.1[kV/cm], respectively.ly.y.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.204-205
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• 2007

Self-seed 층을 이용한 PLZT(9/65/35), 강유전체 박막을 Sol-Gel 법을 이용해 Pt/Ti/$SiO_2$/Si 기판 위에 증착한 후, Self-seed 층에 의한 PLZT(9/65/35) 박막의 구조적, 전기적 특성을 고찰하였다. Seed 층을 도입하지 않은 PLZT 박막의 경우 다결정 상으로 형성되는 것을 알 수 있었으며, seed 층을 도입한 PLZT 박막은 (110) 방향으로 우선 배향됨을 알 수 있었다. 증착된 PLZT(9/65/35) 박막의 유전율 및 유전손살은 10kHz에서 유전율 205, 유전손살 0.029 이었으며, Self-seed layer를 도입한 PLZT 박막의 경우 seed layer를 도입하지 않은 PLZT 박막보다 낮은 온도에서 결정화 되는 것을 관찰 할 수 있었다. Self-seed layer가 도입된 PLZT(9/65/35) 박막의 경우 잔류분극 ($P_r$) 값은 $9.1{\mu}C/cm^2$, 항전계($E_c$)는 47 kV/cm을 나타내었다.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.177-177
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• 2011

Complementary metal-insulator-metal capacitor에서 $SiO_2$는 절연체로 널리 사용되고 있었으나, 반도체 소자의 고직접화로 인한 선폭의 감소로 터널링 효과에 의해 누설전류가 증가하여, 대체 물질에 대한 연구가 활발히 진행되고 있다. 그 중 $ZrO_2$는 고유전율, wide bandgap, 열안정성의 특징을 가지고 있어 대체 물질로 주목 받고 있다. $ZrO_2$ 박막 제작에는 sputter, atomic layer deposition 등의 진공증착을 이용한 방법과 용액을 이용한 sol-gel 법이 있다. 화학용액을 이용한 sol-gel 법은 소자의 패턴을 프린트 할 수 있는 장점과 상대적으로 값싼 공정으로 인해 최근 주목 받고 있지만, 진공증착법에 비해서 연구가 전무한 실정이다. 본 연구에서는 sol-gel 법에 의해 프린트된 $ZrO_2$ 박막의 광특성을 분광타원편광분석법으로 연구하였다. Si 기판위에 0.1 M의 $ZrO_2$ sol을 입힌 뒤에 $300{\sim}700^{\circ}C$의 온도에서 열처리 하였다. 분광타원 편광분석기로 1.12~6.52 eV 에너지 영역에서 측정하였고, $ZrO_2$ 박막의 광특성 분석을 위해서 Tauc-Lorentz 모델을 이용하였다. 그 결과 고온에서의 열처리로 인해 효율이 높아서 소자로 이용할 수 있는 tetragonal 구조를 가진 $ZrO_2$ 박막이 형성됨을 분석할 수 있었다. 본 연구는 sol-gel법으로 제작된 $ZrO_2$ 박막의 고직접, 고속 소자응용성과 비파괴적인 광특성 분석법을 제시하고 있다.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.4
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• pp.273-281
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• 1987

In this work the antioxidant effects of browning reaction products prepared by xylose-tryrtophan reaction system were discussed. The antioxygenic brown pigments were separated by solvent extraction, and column chromatography and isolated by gel filteration. The functional groups of the brown pigments which had antioxidant activity were examined. The brown pigments extracted with methanol showed antioxidant effect and were fractionated in 5portions on DEAE-cellulose column. The elutes with methanol: acetic acid(10:30 v/v sol n(A), methanol: chloroform(95:5 v/v) sol n(C), and chloroform: acetic acid(10:30 v/v) sol n(E) only showed antioxidant activity and their compositions were 22.43, 21.51 and $34.43\%$ respectively. When each fraction on DEAE-cellulose column was reseparated on Sephadex LH-20 column, 2 fractions were obtained from portion A and C respectively. Molecular weights of A, C and E fraction of brown pigments were from 2,600 to 3,700. By elucidation of IR spectra, the pigment fractions which showed a strong antioxidant activity were tearing the indole group. It is suggested that the antioxidant function of the brown pigment is due to hydroxy and amino group. A higher activity of the brown pigment fraction E might be attributed to carboxylic acid or carboxylic ester compounds.

• Elastomers and Composites
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• v.34 no.3
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• pp.199-211
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• 1999

In this work, the effects of the addition of epoxy on the properties of PVC-sol sealants were investigated. PVC-sol was plasticized with dioctyl phthalates(DOP). Two kinds of epoxy resins having different epoxy equivalent weight (E.E.W.) were used. It was found that the properties of the PVC-sol sealants were significantly affected by the contents and types of the added epoxy resins. The viscosity behaviors of the epoxy-modified sealants, in the case of epoxy A addition, the viscosity was decreased with increasing the epoxy contents, but In the case of $CaCO_3$ addition, the viscosity was increased with increasing the $CaCO_3$ contents. The viscosity of epoxy modified sealants aged at $45^{\circ}C$ waterbath was decreased with increasing epoxy contents, since the epoxy acted on the sealants as a stabilizer. The thermal stability of the PVC-sol sealants was slightly improved by adding epoxy. The tensile strength and elongation of sealants modified with epoxy A(two functionalities of epoxy) were increased with increasing the epoxy contents up to a certain epoxy contents but was decreased with further increasing the epoxy contents. In the case of $CaCO_3$ addition, the tensile strength of sealants were decreased with increasing the $CaCO_3$ contents. In view of the electrical properties, such as tan ${\delta}$($0.1{\pm}0.04$) and ${\epsilon}_r$($0.5{\pm}0.04$), it was found that the epoxy modified sealants were as good as insulators.

• Journal of Yeungnam Medical Science
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• v.5 no.2
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• pp.79-86
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• 1988

In the present study the effect of exercise on the conversion rate of ingested glucose to glycogen in the different types of hindlimb skeletal muscles in Sprague-Dawley male rats was studied. The amounts of synthetized glycogen from ingested glucose of fast-twitch white(WV), fast-twitch red(RV), mixed type of fast-twitch white and red(EDL), and slow-twitch(SOL) muscles were determined at 30 and 90 min. after ingestion of 25% glucose solution which contained $^{14}C$-glucose($2m{\ell}(1uCi)$/100gm B. W.)in control and exercise loaded rats. The result was summarized as follows : The about 55% at 30 min. and 70% at 90 min. after glucose ingestion were absorbed from gastrointestinal tract. This result shows no effects of exercise on absorption rate from gastrointestinal tract. The amount of synthetized glycogen of SOL from ingested glucose at 30 and 90 min. after glucose ingestion were highest, whether WV were lowest in hindlimb skeletal muscles in control and exercise loaded rats. In the exercise loaded rats, the amounts of synthetized glycogen of SOL, RV, and EDL at 90 min. after glucose ingestion was much higher than control rats, but not different in WV between exercise-loaded and control rats. At 30 min. after glucose ingestion, only SOL of exercise loaded rats was higher than control rats. In the control rat, the synthesis of glycogen was almost completed during initial 30 minutes. On the other hand, in the exercise loaded rat, except WV was opposite result of control rats, i. e., amounts of synthetized glycogen were major during late period. The amount of synthetized glycogen of liver at 30 and 90 min. after glucose ingestion in exercise loaded rats was higher than control rats. The rate of glycogen synthesis in control and exercise loaded rats were higher between 30-90 minute than initial 30 minute.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07b
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• pp.965-968
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• 2004

Effective transverse Piezoelectric Coefficients $(e_{31,f})$ of thick PZT $(Pb(Zr_{0.52}Ti{0.48}Ti_{0.48})O_3)$ films on $SiN_x/Si$ substrates were measured with PZT thicknesses and top electrode dimensions. $e_{31,f}$ is one of important Parameters characterizing Piezoelectricity of PZT films. Thick PZT films have been used as various sensors and actuators because of their high driving force and high breakdown voltage. Thick PZT films were fabricated on Pt/Ta/$SiN_x$/Si substrates using sol-gel method. Thicknesses of PZT films were $1{\mu}m$ and $1.8{\mu}m$. $|e_{31,f}|$ values of $1.8{\mu}m$-thick-PZT films were higher than those of $1{\mu}$-thick-PZT films. Maximum $|e_{31,f}|$ of $1.8{\mu}$-thick-PZT films was about $50^{\circ}C/m^2$.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.1
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• pp.176-181
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• 2009

In this work, a new type of DSCs based on nanoporous FTO structure is being developed for research aimed at low-cost high-efficiency solar cell application. The nanoporous FTO materials have been prepared through the sol-gel combustion method followed by thermal treatment at $450{\sim}850[^{\circ}C]$. The properties of the nanoporous FTO materials were investigated by IR spectra, BET and TEM analyses, and the photovoltaic performance of the prepared DSCs were examined. It can be seen from the result that the nanoporous FTO exhibited good transparent conductive properties, well suited for DSCs application.