• 분석과학
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• 제7권2호
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• pp.155-164
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• 1994

전형적인 Grimm형 방전관을 제작하고 고주파 방전에 의한 금속 및 세라믹시료 분석에 적용하였다. 금속 알루미늄과 알루미나에 대해 방출 스펙트럼을 관찰하였고 방전에 미치는 고주파의 전력과 알곤 기체의 압력에 대한 영향을 관찰하였으며, 시료와 접촉된 전극에 나타나는 DC-bias voltage를 확인하였다. 또한 SEM 사진을 관찰함으로써 rf-sputtering에 의한 알루미나 표면의 미세구조를 확인하였다. 저합금강(BAS 404-405) 중의 망간성분과 황동시료(NIST 1108-1117) 중의 아연성분에 대해 검량곡선을 작성한 결과 양호한 직선성을 보여 주었다.

• Journal of Radiation Protection and Research
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• 제45권1호
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• pp.35-44
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• 2020

Background: Cadmium zinc telluride (CZT) is a promising material because of a high detection efficiency, good energy resolution, and operability at room temperature. However, the cost of CZT dramatically increases as its size increases. In this study, to achieve a large effective volume with relatively low cost, an array structure comprised of individual virtual Frisch-grid CZT detectors was proposed. Materials and Methods: The prototype consisted of 2 × 2 CZTs, a holder, anode and cathode printed circuit boards (PCBs), and an application-specific integrated circuit (ASIC). CZTs were used and the non-contacting shielding electrode method was applied for virtual Frisch-grid effect. An ASIC was used, and the holder and the PCBs were fabricated. In the current system, because the CZTs formed a common cathode, a total of 5 channels were assigned for data processing. Results and Discussion: An experiment using ¹³⁷Cs at room temperature was conducted for 10 minutes. Energy and timing information was acquired and the depth of interaction was calculated by the timing difference between the signals of both electrodes. Based on obtained three-dimensional position information, the energy correction was carried out, and as a result the energy spectra showed the improvements. In addition, a Compton image was reconstructed using the iterative method. Conclusion: The virtual Frisch-grid CZT detector based on the array structure was developed and the energy spectra and the Compton image were successfully acquired.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.59-60
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• 2008

GaN-based light-emitting diodes (LEDs) with ZnO nanorod arrays on a planar indium tin oxide (ITO) transparent electrode were demonstrated. ZnO nanorods were grown into aqueous solution at low temperature of $90^{\circ}C$. Under 20 mA current injection, the light output efficiency of the LED with ZnO nanorod arrays on ITO was remarkably increased by about 40 % of magnitude compared to the conventional LED with only planar ITO. The enhancement of light output by the ZnO nanorod arrays is due to the formation of side walls and a rough surface resulting in multiple photon scattering at the LED surface.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 춘계학술대회 논문집
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• pp.820-823
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• 2000

The characteristics of wire deflection, surface roughness and roundness were observed on changing discharge time for electrical discharge machining(EDM) of tungsten carbide in various conditions of thickness. The wire deflection was decreased as increasing discharge time and wire tension, the gap of deflection was decreased after thickness 60mm and discharge time of 6$\mu\textrm{s}$ due to the changing from fundamental mode to vibration mode. The deflection is the smallest at the water specific resistivity of 7.5 kΩ ㆍcm. The deflection is found to be decreased as increasing dwell time, and the result is due to the vibration of the pressure and the amount of the dielectric. The component of copper(Cu) and zinc(Zn), which is the main material of wire electrode, was observed for rough wire-cutting EDM of STD-11. This phenomena is found to be decreased as the number of EDM is increased. But it will be improved by changing the material and the shape of wire. The roundness of middle is found to be worse than that of upper and it is increased as the thickness of material is increased.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1262-1263
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• 2008

Recently film-typed dye sensitized solar cell(DSC) attracts much attention with increasing applications for its flexibility and transparency. The ZnO:Al thin film, which serves mainly as transparent conducting electrode, Aluminium-doped zinc oxide(ZnO:Al) thin film has emerged as one of the most promising transparent conducting films since it is inexpensive, mechanically stable, and highly resistant to deoxidation. In this paper ZnO:Al thin film was deposited on the polyethylene terephthalate(PET) substrate by the capacitively coupled r. f. magnetron sputtering method. The effects of gas pressure and r. f. discharge power on the morphological, electrical and optical properties of ZnO:Al thin film were studied. Especially the variation in substrate thickness after sputtering and surface morphology of the substrate were investigated and clarified. The results showed that the film deposited on the PET substrate at r. f. discharge power of 180 W showed the minimum resistivity of about $1.5{\times}10^{-3}{\Omega}-cm$ and a transmittance of about 93%.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.537-542
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• 2000

Wire deflection, surface roughness and roundness were observed on changing discharge time for electrical discharge machining(EDM) of STD-11 in various conditions of thickness. The wire deflection was decreased as increasing discharge time and wire tension. The deflection is the smallest at the speed of wire of 10.6m/min and the water specific resistivity of 5k$\Omega$.cm. The deflection is found to be decreased as increasing dwell time. But if the water pressure is high, it is found not to be changed after the vibration of 4sec. The component of copper(Cu) and zinc(Zn), which is the main material of wire electrode, is observed for rough wire-cutting EDM of STD-11. This phenomena is found to be similar in spite of the change of EDM energy level. But it will be improved by changing the material and the shape of wire. The roundness of middle is found to be worse than that of upper and it is increased as the thickness of material is increased.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1482-1484
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• 2002

Transparent conductive oxides (TCO) are necessary as front electrode for most thin film solar cell. In our paper, transparent conducting aluminum-doped Zinc oxide films (ZnO:Al) were prepared by rf magnetron sputtering on glass (Corning 1737) substrate as a variation of the deposition condition. After deposition, the smooth ZnO:Al films were etched in diluted HCI (0.5%) to examine the electrical and surface morphology properties as a variation of the time. The most important deposition condition of surface-textured ZnO films by chemical etching is the processing pressure and the substrate temperature. In low pressures (0.9mTorr) and high substrate temperatures $({\leq}300^{\circ}C)$, the surface morphology of films exhibits a more dense and compact film structure with effective light-trapping to apply the silicon thin film solar cells.

• Bulletin of the Korean Chemical Society
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• 제32권3호
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• pp.847-851
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• 2011

This study examined In-Zn-Sn-O (IZTO) films deposited on glass substrates by pulsed DC magnetron sputtering with various substrate temperatures. The structural, electrical, optical properties were analyzed. Xray diffraction showed that the IZTO films prepared at temperatures > $150^{\circ}C$ were crystalline which adversely affected the electrical properties. Amorphous IZTO films prepared at $100^{\circ}C$ showed the best properties, such as a low resistivity, high transmittance, figure of merit, and high work function of $4.07{\times}10^{-4}\;{\Omega}$, 85%, $10.57{\times}10^{-3}\;{\Omega}^{-1}$, and 5.37 eV, respectively. This suggests that amorphous IZTO films deposited at relatively low substrate temperatures ($100^{\circ}C$) are suitable for electrode applications, such as OLEDs as a substitute for conventional crystallized ITO films.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.417-418
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• 2008

Transparent conductive oxide (TCO) are necessary as front electrode or anti-reflecting coating for increasing efficiency of LED and Photodiode. In this paper, aluminum-doped Zinc oxide films(AZO) were prepared by DC magnetron sputtering on glass(corning 1737) and Si substrate at temperature of $100^{\circ}C$ and then annealed at temperature of $400^{\circ}C$ for 1hr in Ar and vaccum. The AZO films were etched in diluted HCL (0.5 %) to examine the surface morphology properties. After annealing, Structural and electrical property were investigated. The c-axis orientation along (002) plane was enhanced and the electrical resistivity of the AZO film decreased from $1.1\times10^{-1}$ to $1.6\times10^{-2}{\Omega}cm$. We observed textured structure of AZO thin film etched for 2s.

• Korean Chemical Engineering Research
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• 제46권5호
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• pp.1013-1016
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• 2008

본 연구에서는 폐수 내 존재하는 질산성 질소를 제거하기 위해 캐소드물질로 철(Fe), 구리(Cu), 니켈(Ni), 아연(Zn)을 선택하여 전기화학적 환원반응 특성을 조사하였다. $NO_3^-$로부터 $NH_3$로의 변환반응에 있어서 Zn이 가장 우수한 촉매 특성을 가지고있으며, pH 8.5에서 가장 높은 질산성 질소 제거 효율을 나타내었다. 전극표면에서 질산성 질소는 아질산성 질소로 환원된 후, 암모니아성 질소로 전환되는 것을 확인하였으며 암모니아성 질소는 HOCl과의 화학반응을 통하여 질소 형태로 완전히 제거할 수 있었다.