• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.383-386
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• 1999

The importance of rechargeable lithium cells has been emphasized. So a large variety of materials has been discovered and evaluated for use as reversible cathodes and electroyltes. This paper examines the charge/discharge properties and the charge/discharge cycling life of Li$_2$O-P$_2$O-V$_2$O$_{5}$Li cells. In audition, DTA tests were carried out on Li$_2$O-P$_2$O-V$_2$O$_{5}$ glass. As a result the best performance was achieved when 0.3Li$_2$O-0.1P$_2$O$_{5}$-0.6V$_2$O$_{5}$Li cells was mixed with SP270. that is discharge capacity of 240mAh/g have been achieved. In addition this battery exhibited good cycling performance. Considering these results we expected utilization of the Li$_2$O-P$_2$O-V$_2$O$_{5}$ glass as a cathode material in a secondary battery.y battery.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2003년도 정기총회 및 학술대회
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• pp.133-138
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• 2003

가변길이 부호는 정보원(source)의 통계적인 특성을 이용하여 부호화 효율을 높이지만. 잡음이 심한 전송환경에선 비트에 대한 오류가 발생하면 심각하게 손상되는 단점을 가진다. 이러한 가변길이 부호의 문제를 해결하기 위해 양방향 가변길이 부호가 제안되었다. 양방향 가변길이 부호는 순방향과 역방향으로 복호가 가능하여 전송 오류로 인해 손상된 비디오 비트열에서 데이터를 복구할 수 있다. 부호의 자유거리(free distance)는 부호자체가 전송 오류에 얼마나 강인한지를 보여주는 척도로 사용된다. 양방향 가변길이 부호의 자유거리(free distance)의 최소 값은 1이므로 비디오 비트열 손상 자체를 방지할 수는 없다 본 논문에서는 자유거리(free distancs)의 최소 값을 증가시켜 전송오류에 더욱 강인한 새로운 양방향 가변길이 부호의 선계 기법을 제안한다. 제안된 알고리즘은 주어진 Huffman 부호와 평균부호길이 함수의 특성을 이용하여 자유거리의 조건을 만족하면서 동시에 부호화 효율을 높여 기존의 알고리즘보다 향상된 성능을 보여준다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.118-119
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• 2005

PRAM (Phase Change Random Access Memory) is well known to use reversible phase transition between amorphous (high resistance) and crystalline (low resistance) states of chalcogenide thin film by electrical Joule heating. In this paper, we introduce a stack-type PRAM device with a novel GST/TiAlN structures (GST and a heating layer of TiAlN), and report its electrical switching properties. XRD analysis result of GST thin film indicates that the crystallization of the GST film start at about $200^{\circ}C$. Electrical property results such as I-V & R-V show that the phase change switching operation between set and reset states is observed, as various input electrical sources are applied.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.943-946
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• 2004

We have investigated to observe the photoisomerization using the mixture solutions in chloroform and LB monolayers mixed with DPPA and BASH containing azobenzene group which has reversible to cis-trans by light irradiation.. Spreading solutions for the LB films were Prepared in chloroform($5.0{\times}10^{-5}mol/L$). We investigated the photoisomerization and property of the organic ultra thin film of fatty acid containing azobenzene was Prepared on the glass plate by LB method. As a result, the absorption spectra of 8A5H and DPPA mixture of LB films was induced to photoisomerization by alternating irradiation of ultraviolet and visible light, because the condensation of pure azobenzene monolayers was loosened by the introduction of phospholipid into the monolayers, and the molecular high aggregation in pure azobenzene monolayers is also weakened by the introduction of phospholipid. We found that it was reversibly induced to cis-trans photoisomerization in a various mixture molar ratio.

• Macromolecular Research
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• 제16권3호
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• pp.200-203
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• 2008

A conducting polymer layer was introduced into the pore surface of mesoporous carbon via vapor infiltration of a monomer and subsequent chemical oxidative polymerization. The polypyrrole, conducting polymer has attracted considerable attention due to the high electrical conductivity and stability under ambient conditions. The mesoporous carbon-polypyrrole nanocomposite exhibited the retained porous structure, such as mesoporous carbon with a three-dimensionally connected pore system after intercalation of the polypyrrole layer. In addition, the controllable addition of pyrrole monomer can provide the mesoporous carbon-polypyrrole nanocomposites with a tunable amount of polypyrrole and texture property. The polypyrrole layer improved the electrode performance in the electrochemical double layer capacitor. This improved electrochemical performance was attributed to the high surface area, open pore system with three-dimensionally interconnected mesopores, and reversible redox behavior of the conducting polypyrrole. Furthermore, the correlation between the amount of polypyrrole and capacitance was investigated to check the effect of the polypyrrole layer on the electrochemical performance.

• 접착 및 계면
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• 제22권2호
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• pp.47-56
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• 2021

자기치유 소재를 이용하여 강판을 코팅하는 경우, 코팅 소재에 상처가 날 경우 스스로 상처를 치유하여 강판이 부식되는 것을 방지할 수 있다. 하지만 자기치유 과정에는 시간이 소요되며, 따라서 자기치유가 되기 전에 강판의 상처가 부식 될 수 있다. 본 연구에서는 가역적인 hindered urea bond(HUB)를 통하여 가교 결합을 형성하면서 동시에 부식 방지제로써 작용하는 DTBEDA를 이용하여 듀얼자기치유 메커니즘을 가지는 코팅 소재를 제조하였다. 또한 제조된 소재를 강판에 코팅하여 의료용 메스와 나노/마이크로 압입시험기를 통하여 스크래치에 대한 자기치유 성능을 확인하였으며, DTBEDA의 내부식성 효과를 전기화학 임피던스 분광법(EIS)을 통하여 분석하였다.

• 보존과학회지
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• 제27권1호
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• pp.115-121
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• 2011

석조 문화재의 복원을 위하여 우레탄 복원제를 제조하였다. 제조된 우레탄 복원제는 그간 석조 문화재 복원용 재료로 주로 사용해 왔던 에폭시계 복원제 정도의 강한 접착 강도와 인장 강도를 나타내고 있으며, 충진성, 수축성, 도색성 등의 물성 역시 에폭시계 복원제와 유사하게 제조되었다. 특히, 이 우레탄 복원제는 그간 가장 큰 문제점으로 대두되었던 에폭시계 복원제의 황변 현상과 비가역성 문제를 해결함으로서, 석조문화재의 복원의 항구성과 지속적인 안정성을 부여할 수 있을 것으로 보인다. 또 본 복원제를 메움제와 접착제로 직접 적용하여 사용하였으며, 이를 재 용해하여 복원에 사용된 우레탄을 제거할 수 있어 본 복원제의 가역성을 나타내었다. 이 복원제는 작업 환경에 따라 복원자가 가사 시간을 조정할 수 있도록 제조되어 사용의 편리성 또한 증진시켰다. 또 이 복원제는 강한 접착력과 인장 강도를 가지고 있어 석조문화재 이외의 도자기나 금속 문화재 등의 다양한 문화재의 메움제나 접착제로 사용이 가능할 것으로도 사료된다.

• 한국수소및신에너지학회논문집
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• 제20권6호
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• pp.505-511
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• 2009

The hydriding and electrochemical characteristics of Zr-based $AB_2$ alloy produced by gas atomization have been extensively examined. For the particle morphology of the as-cast and gas-atomized powders, it can be seen that the mechanically crushed powders are irregular, while the atomized powder particles are spherical. The increase of jet pressure of gas atomization process results in the decrease of hydrogen storage capacity and the slope of plateau pressure significantly increases. TEM and EDS studies showed the increase of jet pressure in the atomization process accelerated the phase separation within grain of the gas-atomized alloy, which brought about a poor hydrogenation property. However, the gas-atomized $AB_2$ alloy powders produced by jet pressure of 50 bar kept up the reversible $H_2$ storage capacity and discharge capacity similar to the mechanically crushed particles. In addition, the electrode of gas-atomized Zr-based $AB_2$ alloy of 50 bar showed improved cyclic stability over that of the cast and crushed particulate, which is attributed to the restriction of crack propagation by grain boundary and dislocation with ch/discharging cycling.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권5호
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• pp.201-205
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• 2003

We synthesized dendrimers containing light switchable units, azobenzene group. And the dendrimer containing 48 pyridinepropanol functional end group, which could form a complex structure with metal ions was synthesized. To apply to the molecular level devices or data storage system using Langmuir-Blodgett(LB) film, we firstly investigated the monolayer behavior using the surface pressure-area($\pi$-A) isotherms at air-water interface. And then the surface pressure shift of monolayer by light irradiation was also measured to the dendrimer with azobezene group. As a result, the monolayer of dendrimer with azobenzene group showed the reversible photo-switching behavior by the isomerization of azobenzene group in their periphery. The samples for electrical measurement were fabricated to two types which were pure dendrimer with pyridinepropanol group and its complexes with $Pt^4+$ ions by LB method. We have studied the electrical properties of the ultra thin dendrimer LB films investigated by the current-voltage(I-V) characteristics of Metal/Dendrimer LB films/Metal(MIM) structure. And we have investigated different results in the surface activity at the air-water interface as well as the electrical properties for the monolayers of pure dendrimer with pyridinevopanol group and its complex with $Pt^4+$ ions. In conclusion, it is demonstrated that the metal ion around dendrimer with pyri야nepropanol group can contribute to make formation of network structure among dendrimers and it result from the change of electrical properties. This results suggest that the dendrimers with azobenzene group and pvridinedropanol group can be applied to high efficient nano-device of molecular level.

• 대한전기학회논문지:시스템및제어부문D
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• 제52권5호
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• pp.201-201
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• 2003

We synthesized dendrimers containing light switchable units, azobenzene group. And the dendrimer containing 48 pyridinepropanol functional end group, which could form a complex structure with metal ions was synthesized. To apply to the molecular level devices or data storage system using Langmuir-Blodgett(LB) film, we firstly investigated the monolayer behavior using the surface pressure-area($\pi$-A) isotherms at air-water interface. And then the surface pressure shift of monolayer by light irradiation was also measured to the dendrimer with azobezene group. As a result, the monolayer of dendrimer with azobenzene group showed the reversible photo-switching behavior by the isomerization of azobenzene group in their periphery. The samples for electrical measurement were fabricated to two types which were pure dendrimer with pyridinepropanol group and its complexes with $Pt^4+$ ions by LB method. We have studied the electrical properties of the ultra thin dendrimer LB films investigated by the current-voltage(I-V) characteristics of Metal/Dendrimer LB films/Metal(MIM) structure. And we have investigated different results in the surface activity at the air-water interface as well as the electrical properties for the monolayers of pure dendrimer with pyridinevopanol group and its complex with $Pt^4+$ ions. In conclusion, it is demonstrated that the metal ion around dendrimer with pyri야nepropanol group can contribute to make formation of network structure among dendrimers and it result from the change of electrical properties. This results suggest that the dendrimers with azobenzene group and pvridinedropanol group can be applied to high efficient nano-device of molecular level.