• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2009년도 학술발표대회
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• pp.118-119
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• 2009

As the rapid development of the electronics, the demand for portable electronics and wireless sensors is growing faster, also with the increased needs of one material which can power it automatically, and then power the electrical devices. The piezoelectric effect of the PVDF material can be used for this. So in this paper, PVDF multilayer films were made for this aim. Make the PVDF / DMAc solution in the 10% concentration; use the spin coater technique to make films with the optimum process parameters: the spin rate is 1260rpm; the spin time is 70s; the dry temperature is 100$^{\circ}C$; the dry time is 30mins. And also, for obtaining the higher $\beta$-phase crystallinity, put the Ca(NH3)2.4H2O into the PVDF / DMAc solution system.

• 한국진공학회지
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• 제6권3호
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• pp.242-248
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• 1997

기존의 다공질 실리콘 제작 방법인 chemical etching 방법을 병행하면서 새로운 제 작 방법으로서 dry etching 기술을 적용하여 다공질 실리콘을 제작하였다. 또한, 비교를 위 해 E-beam lithography 기술로 실리콘 구조물을 제작하였는데 이 경우 기술상 문제로 약 0.3$\mu\textrm{m}$의 직경을 가진 구조물이 최소의 크기였다. 따라서 새로운 방법으로 4인치 wafer위에 mask 역할을 해주는 다이아몬드 분말을 spin coater로 입힌 후 Reactive Ion Etching(RIE) 방법으로 미세구조의 다공질 실리콘을 제작하였다. 다양한 조건으로 제작된 sample들의 morphology를 SEM과 AFM 등을 이용하여 분석하였고 이 morphology에 대응하는 PL스펙 트럼을 측정하였다. 그 결과, 다이아몬드 분말을 이용한 dry etching방법으로 제작된 다공질 실리콘의 PL peak의 위치가 chemical etching 방법의 다공질 실리콘의 PL peak 위치인 760nm에 비해 높은 에너지인 590nm로 나타났다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제37회 하계학술대회 초록집
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• pp.400-400
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• 2009

• 한국재료학회지
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• 제26권2호
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• pp.84-89
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• 2016

We present the rectifying and nitrogen monoxide (NO) gas sensing properties of an oxide semiconductor heterostructure composed of n-type zinc oxide (ZnO) and p-type copper oxide thin layers. A CuO thin layer was first formed on an indium-tin-oxide-coated glass substrate by sol-gel spin coating method using copper acetate monohydrate and diethanolamine as precursors; then, to form a p-n oxide heterostructure, a ZnO thin layer was spin-coated on the CuO layer using copper zinc dihydrate and diethanolamine. The crystalline structures and microstructures of the heterojunction materials were examined using X-ray diffraction and scanning electron microscopy. The observed current-voltage characteristics of the p-n oxide heterostructure showed a non-linear diode-like rectifying behavior at various temperatures ranging from room temperature to $200^{\circ}C$. When the spin-coated ZnO/CuO heterojunction was exposed to the acceptor gas NO in dry air, a significant increase in the forward diode current of the p-n junction was observed. It was found that the NO gas response of the ZnO/CuO heterostructure exhibited a maximum value at an operating temperature as low as $100^{\circ}C$ and increased gradually with increasing of the NO gas concentration up to 30 ppm. The experimental results indicate that the spin-coated ZnO/CuO heterojunction structure has significant potential applications for gas sensors and other oxide electronics.

• 한국재료학회지
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• 제25권4호
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• pp.171-176
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• 2015

We present the detection characteristics of nitrogen monoxide(NO) gas using p-type copper oxide(CuO) thin film gas sensors. The CuO thin films were fabricated on glass substrates by a sol-gel spin coating method using copper acetate hydrate and diethanolamine as precursors. Structural characterizations revealed that we prepared the pure CuO thin films having a monoclinic crystalline structure without any obvious formation of secondary phase. It was found from the NO gas sensing measurements that the p-type CuO thin film gas sensors exhibited a maximum sensitivity to NO gas in dry air at an operating temperature as low as $100^{\circ}C$. Additionally, these CuO thin film gas sensors were found to show reversible and reliable electrical response to NO gas in a range of operating temperatures from $60^{\circ}C$ to $200^{\circ}C$. It is supposed from these results that the p-type oxide semiconductor CuO thin film could have significant potential for use in future gas sensors and other oxide electronics applications using oxide p-n heterojunction structures.

• Bulletin of the Korean Chemical Society
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• 제29권6호
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• pp.1233-1242
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• 2008

The hydration effect on the intrinsic magnetism of natural salmon double-strand DNA was explored using electron magnetic resonance (EMR) spectroscopy and superconducting quantum interference device (SQUID) magnetic measurements. We learned from this study that the magnetic properties of DNA are roughly classified into two distinct groups depending on their water content: One group is of higher water content in the range of 2.6-24 water molecules per nucleotide (wpn), where all the EMR parameters and SQUID susceptibilities are dominated by spin species experiencing quasi one-dimensional diffusive motion and are independent of the water content. The other group is of lower water content in the range of 1.4-0.5 wpn. In this group, the magnetic properties are most probably dominated by cyclotron motion of spin species along the helical π -way, which is possible when the momentum scattering time (${\tau}_k$) is long enough not only to satisfy the cyclotron resonance condition (${\omega}_c{\tau}_k$ > 1) but also to induce a constructive interference between the neighboring double helices. The same effect is reflected in the S-shaped magnetization-magnetic field strength (M-H) curves superimposed with the linear background obtained by SQUID measurements, which leads to larger susceptibilities at 1000 G when compared with the values at 10,000 G. In particular, we propose that the spin-orbital coupling and Faraday's mutual inductive effect can be utilized to interpret the dimensional crossover of spin motions from quasi 1D in the hydrate state to 3D in the dry state of dsDNA.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2007년도 춘계학술발표대회 및 제12회 신소재 심포지엄
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• pp.26.2-26.2
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• 2007

• Journal of Information Display
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• 제6권2호
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• pp.19-24
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• 2005

The density controlled carbon nanotubes (CNTs) are grown on the iron acetate nanoparticles by using the freeze-dry method. The iron-acetate [Fe(II)$(CH_3COO)_2$] solution is used to prepare the catalytic iron nanoparticles. The density of CNTs is controlled in order to enhance the field emission process. Furthermore, the patterning of the iron nanoparticle catalyst-layer for the fabrication of electronic devices is simply achieved by using alkaline solution, TMAH (tetramethylammonium hydroxide). We applied this patterning process of catalyst layer to form the electron emitter with under-gate type triode structure.

• 한국환경과학회지
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• 제25권3호
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• pp.373-383
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• 2016

The aim of this study is to determine the exposure concentration of tetrabromobisphenol A(TBBPA) in southwestern coast and their photodecomposition rate. Also, it is to identify the radical species of the photodecomposition of TBBPA and their reactive byproducts using the electron spin resonance(ESR) method. TBBPA was not detected in any of the sea water samples from Mokpo, Gunsan, or Goheung. The sediment samples from Mokpo contained not detection(N.D)~50.0 ng/g dry wt., while those from Gunsan contained N.D~28.5 ng/g dry wt. and those from Goheung contained N.D~7.3 ng/g dry wt. The photodecomposition rates were $2.56{\times}10^{-6}/hr$ by visible light(400 nm), $7.98{\times}10^{-6}/hr$ by ultraviolet light(300 nm <), and $6.78{\times}10^{-6}/hr$ by sunlight. Also, we confirmed that singlet oxygen and hydroxyl radicals are the key reactive oxygen species at wavelengths greater than 400 and 300 nm, respectively. This study shows that the main byproducts formed during irradiation at wavelengths above 300 nm are 2,6-dibromobenzosemiquinone radical(2,6-$DBSQ{\cdot}^-$) and g-value 2.0048 doublet spectrum.

• 한국세라믹학회지
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• 제40권2호
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• pp.153-158
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• 2003

Photosensitive sol solution을 이용한 self pattern된 박막은 photoresist/dry etching process에 비해 박막의 제조과정이 간단하다는 장점을 가지고 있다. 이 연구에서는 강유전성 메모리소자의 산화물 전극재료로 사용되고 있는 La$_{0.5}$Sr$_{0.5}$CoO$_3$(LSCO)극 photosensitive sol solution을 이용하여 spin coating법으로 제조하였으며 출발원료는 La-2methoxyethoxide, Sr-ethoxide, Co-2methoxyethoxide를 사용하였다. LSCO gel 박막에 UV 노광시간을 증가시킴에 따라 M(metal)-O-M 결합이 생성되면서 metal $\beta$-diketonate의 UV 흡수 피크 강도는 감소되었고 LSCO gel 박막에 UV조사에 따른 용해도 차이가 생기면서 fine patterning 을 얻을 수 있었다. 68$0^{\circ}C$ 이상의 온도로 대기 중에서 열처리된 LSCO 박막은 perovskite 상을 나타내었고 74$0^{\circ}C$에서 가장 낮은 비저항값(4$\times$10￣$^3$Ωcm)을 얻을 수 있었다.