• 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.

• 한국항행학회논문지
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• 제23권2호
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• pp.172-178
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• 2019

본 논문에서는 LTCC 다층기판으로 구현할 수동 소자를 수축공정과 무수축공정으로 구분하여 설계, 제작하고 분석하였다. 유전율 7 또는40의 두 종류 세라믹 소재를 사용하여 기본 형태의 수동소자를 다양하게 두 가지 공정으로 제작하여 특성을 비교하였다. 유전율40 기판을 사용할 때 수축공정은 X, Y 방향에서 17%, Z 방향에서 36%의 수축율을 보이는 것과 비교하여, 무수축공정은 X,Y 방향에서 변화하지 않고 Z 방향으로만 43% 수축하여 평면상에서 높은 치수 정밀도와 표면 평탄도를 얻을 수 있다. 측정 값으로 부터 매개 변수를 이용한 경험적 해석 식을 이용하여 제작한 LTCC 소자의 인덕턴스 및 커패시턴스를 추정하였으며 설계 라이브러리 형태로 구현하였다. 유전율과 제작 공정에 따라 인덕터의 권선수와 단위 면적에 따른 커패시턴스를 측정하여 권선수 및 단위면적에 따른 소자값을 예측할 수 있는 다항식을 제시하였다.

• 대한금속재료학회지
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• 제50권8호
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• pp.613-618
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• 2012

We report on electrical and mechanical properties of silicon nitride ($SiN_x$) films deposited by a plasma enhanced chemical vapor deposition (PECVD) method at $200^{\circ}C$ from $SiH_4$ highly diluted in $N_2$. The films were also prepared from $SiH_4$ diluted in He for comparison. The $N_2$ dilution was also effective in improving adhesion of the $SiN_x$ films, fascilitating construction of thin film transistors (TFTs). Metal-insulator-semiconductor (MIS) and Metal-insulator-Metal (MIM) structures were used for capacitance-voltage (C-V) and current-voltage (I-V) measurements, respectively. The resistivity and breakdown field strength of the $SiN_x$ films from $N_2$-diluted $SiH_4$ were estimated to be $1{\times}10^{13}{\Omega}{\cdot}cm$, 7.4 MV/cm, respectively. The MIS device showed a hysteresis window and a flat band voltage shift of 3 V and 0.5 V, respectively. The TFTs fabricated by using these films showed a field-effect mobility of $0.16cm^2/Vs$, a threshold voltage of 3 V, a subthreshold slope of 1.2 V/dec, and an on/off ratio of > $10^6$.

• 대한방사선치료학회지
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• 제24권2호
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• pp.85-93
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• 2012

목 적: 호흡에 의한 장기의 움직임이 큰 흉부와 상복부에 위치한 종양의 토모테라피 치료 시 움직임을 최소화하기 위해 노력으로 호흡 조절 시스템을 적용하지만 여러 제약이 따라 이용이 제한적이었다. 이에 본 연구에서는 토모테라피 치료 시 효율적인 호흡 조절을 위한 ABCHES system의 적용 가능성 및 유용성을 평가해 보고자 하였다. 대상 및 방법: 본원에서 흉부와 상복부에 위치한 폐와 간, 쓸개, 췌장에 토모테라피 치료를 받은 5명의 환자를 대상으로 하였다. 모든 환자에게 ABCHES를 사용하여 자유 호흡법과 얕은 호흡법을 각각 교육한 후 치료 계획용 4D-CT를 실시하여 총 10개의 4차원 단층촬영영상을 획득 하였다. 한명의 전공의는 각 영상의 최대 흡기, 최대 호기, 호흡의 중간 위상, Average CT이미지에서 육안적으로 보이는 종양과 주변 정상장기를 그렸으며 MIM에서 선량체적 히스토그램과 종양의 움직임에 대한 정량적 분석을 실시하였다. 자유 호흡과 얕은 호흡 상태에서 장기의 움직임은 총 여섯 방향에서 평가하였고 주변 장기에 조사된 방사선량을 비교하였다. 결 과: 5명의 환자 중 호흡 조절 장치인 ABCHES를 이용하여 자유 호흡과 얕은 호흡 상태에서 장기의 움직임이 5 mm 이상 움직인 호흡은 자유 호흡이 12번인 반면 얕은 호흡에서는 2번으로 감소되었다. 선량 체적 히스토그램을 통한 비교 분석 결과 두 호흡간 치료 체적과 종양조직 주변 정상 장기 2개의 평균 선량 값과 정상조직에 방사선이 조사되는 용적에서 ABCHES를 이용한 얕은 호흡이 자유 호흡에 비해 모두 낮은 치료 결과 값을 확인 할 수 있었다. 결 론: ABCHES를 사용하여 규칙적이고 정확한 얕은 호흡을 함으로써 토모테리피 치료 시 유용성과 호흡에 따른 종양의 움직임을 최소화 할 수 있음을 확인 하였고, 주변 정상조직에 불필요하게 조사되는 방사선을 감소시킬 수 있었다.

• 한국재료학회지
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• 제22권2호
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• pp.61-65
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• 2012

A $Li_2O-2SiO_2$ ($LS_2$) glass was investigated as a lithium-ion conducting oxide glass, which is applicable to a fast ionic conductor even at low temperature due to its high mechanical strength and chemical stability. The $Li_2O-2SiO_2$ glass is likely to be broken into small pieces when quenched; thus, it is difficult to fabricate a specifically sized sample. The production of properly sized glass samples is necessary for device applications. In this study, we applied spark plasma sintering (SPS) to fabricate $LS_2$ glass samples which have a particular size as well as high transparency. The sintered samples, $15mm\phi{\times}2mmT$ in size, ($LS_2$-s) were produced by SPS between $480^{\circ}C$ and $500^{\circ}C$ at 45MPa for 3~5mim, after which the thermal and dielectric properties of the $LS_2$-s samples were compared with those of quenched glass ($LS_2$-q) samples. Thermal behavior, crystalline structure, and electrical conductivity of both samples were analyzed by differential scanning calorimetry (DSC), X-ray diffraction (XRD) and an impedance/gain-phase analyzer, respectively. The results showed that the $LS_2$-s had an amorphous structure, like the $LS_2$-q sample, and that both samples took on the lithium disilicate structure after the heat treatment at $800^{\circ}C$. We observed similar dielectric peaks in both of the samples between room temperature and $700^{\circ}C$. The DC activation energies of the $LS_2$-q and $LS_2$-s samples were $0.48{\pm}0.05eV$ and $0.66{\pm}0.04eV$, while the AC activation energies were $0.48{\pm}0.05eV$ and $0.68{\pm}0.04eV$, respectively.