• 한국산학기술학회논문지
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• 제8권3호
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• pp.472-476
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• 2007

본 연구에서는 p-형 ZnO 박막 증착법 및 특성의 안정화 방안에 대하여 조사하였다. p-형 ZnO는 AlAs와 ZnO target을 사용하여 RF magnetron sputtering 기법으로 co-deposition하여 제작하였으며 특성 변화를 조사하기 위해 $250^{\circ}C$에서 144시간까지 스트레스 인가 시간을 변화하며 Photoluminescence 및 Hall 측정을 수행하였다. 연구 결과 co-deposition 은 p-형 박막을 제작하기 위해 유효한 방법인 것으로 밝혀졌으며, 특히 고온에서 이루어지는 과정을 수행하기 전 30% H2O2용액에 1분간 처리하는 것이 이후의 열처리 과정 중 발생하는 특성 변화를 크게 억제하는 것으로 관찰되었다.

• 한국산학기술학회논문지
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• 제8권5호
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• pp.1057-1061
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• 2007

본 연구에서는 AlAs와 ZnO target을 사용하여 RF magnetron sputtering 시스템에서 layer-by-layer 방법으로 증착한 ZnO 박막의 특성에 대하여 조사하였다. 또한 열처리 전에 $H_2O_2$용액을 사용한 처리가 박막 특성에 미치는 영향도 조사하였다. 연구 결과 열처리 조건에 따라 n-형 또는 p-형 박막이 형성되는 것으로 관찰되었다. 이러한 결과는 박막의 전도 형태를 임의로 수정할 수 있음을 의미하는 동시에 박막 특성의 열적 불안정성을 암시하는 것이기도 하다. 144시간까지 스트레스를 인가한 후 측정한 박막 특성 결과 열처리 과정 중 발생하는 이러한 박막 특성 변화는 열처리 전 박막을 30% $H_2O_2$용액에 1분간 처리함으로써 억제할 수 있는 것으로 관찰되었다.

• Membrane and Water Treatment
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• 제14권3호
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• pp.129-140
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• 2023

The appropriate injection of H₂O₂ is essential to produce hydroxyl radicals (OH·) by mixing H₂O₂ quickly and exposing the resulting H₂O₂ solution to UV irradiation. This study focused on evaluating mixing device of H₂O₂ as a design factor of UV/H₂O₂ AOP pilot plant using a surface water. The experimental investigation involved both experimental and model-based analyses to evaluate the mixing effect of different devices available for the H₂O₂ injection of a tubular hollow pipe, elliptical type of inline mixer, and nozzle-type injection mixer. Computational fluid dynamics analysis was employed to model and simulate the mixing devices. The results showed that the elliptical type of inline mixer showed the highest uniformity of 95%, followed by the nozzle mixer with 83%, and the hollow pipe with only 18%, after passing through each mixing device. These results indicated that the elliptical type of inline mixer was the most effective in mixing H₂O₂ in a bulk. Regarding the pressure drops between the inlet and outlet of pipe, the elliptical-type inline mixer exhibited the highest pressure drop of 15.8 kPa, which was unfavorable for operation. On the other hand, the nozzle mixer and hollow pipe showed similar pressure drops of 0.4 kPa and 0.3 kPa, respectively. Experimental study showed that the elliptical type of inline and nozzle-type injection mixers worked well for low concentration (less than 5mg/L) of H₂O₂ injection within 10% of the input value, indicating that both mixers were appropriate for required H₂O₂ concentration and mixing intensity of UV/ H₂O₂ AOP process. Additionally, the elliptical-type inline mixer proved to be more stable than the nozzle-type injection mixer when dealing with highly concentrated pollutants entering the UV/H₂O₂ AOP process. It is recommended to use a suitable mixing device to meet the desired range of H₂O₂ concentration in AOP process.

• 반도체디스플레이기술학회지
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• 제16권2호
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• pp.9-14
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• 2017

$ISnO_2$ thin films were prepared on p-type and n-type Si substrates to research the interface characteristics between $SnO_2$ and substrate. After the annealing processes, the amorphous structure was formed at the interface to make a Schottky contact. The O 1s spectra showed the bond of 530.4 eV as an amorphous structure, and the Schottky contact. The analysis by the deconvoluted spectra was observed the drastic variation of oxygen vacancies at the amorphous structure because of the depletion layer is directly related to the oxygen vacancy. $SnO_2$ thin film changed the electrical properties depending on the characteristics of substrates. It was confirmed that it is useful to observe the Schottky contact's properties by complementary using the XPS analysis and I-V measurement.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.343-343
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• 2011

ZnO has been introduced as one of the good candidates for next generation opto-electronics. Recently, ZnO is known to be suitable for the transparent electrode in organic solar cells and light emitting devices. The contact with n-type organic material has been studied due to the n-type properties of ZnO. However, the surface of ZnO has shown different electronic property with respect to its surface orientation. Therefore, it is presumed that there are differences in the interfacial electronic structures between organic materials and ZnO with different orientation. Therefore, it is required to classify the interfacial electronic structures according to the surface orientation of ZnO. In this study, we measured the interfacial electronic structures between the ZnO substrate having various orientations and a typical n-type organic material, tris-(8-hydroxyquinoline) aluminum (Alq3). In-situ x-ray and ultraviolet photoelectron spectroscopy measurements revealed the interfacial electronic structures. We found the changes in the electronic structures with respect to the orientation of ZnO substrate and it could be used to improve the contact between ZnO and Alq3.

• 한국대기환경학회지
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• 제26권1호
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• pp.1-9
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• 2010

In this study, the selective catalytic reduction of $NO_x$ with ammonia was carried out in a filter bag support reactor. The experiments were performed by powder type $MnO_x$ and $V_2O_5$/$TiO_2$ catalyst at low temperature between 130 and $250^{\circ}C$. Also, the effect of $SO_2$ and $H_2O$ on the NO conversion was investigated under our test conditions. The powder type catalysts were analyzed by X-ray photoelectron spectrum (XPS), X-ray diffraction(XRD), scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA). It was observed that NO removal efficiency of the powder type $V_2O_5$/$TiO_2$ catalyst was 85% at low temperature($200^{\circ}C$) under presence of oxygen and that of $MnO_x$ was 50% at the same condition. The powder type $V_2O_5$/$TiO_2$ catalyst, in conclusion, was found to be available for SCR reaction in a filter bag support system.

• Transactions on Electrical and Electronic Materials
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• 제12권4호
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• pp.169-173
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• 2011

In this study, Al-N codoped p-type zinc oxide (ZnO) thin films were deposited on Si and homo-buffer layer templates in a mixture of $N_2$ and $O_2$ gas with ceramic ZnO:(2 wt% $Al_2O_3$) as a sputtering target using DC- magnetron sputtering. X-ray diffraction spectra of two-theta diffraction showed that all films have a predominant (002) peak of ZnO Wurtzite structure. As the $N_2$ fraction in the mixed $N_2$ and $O_2$ gases increased, field emission secondary electron microscopy revealed that the surface appearance of codoped films on Si varied from smooth to textured structure. The p-type ZnO thin films showed carrier concentration in the range of $1.5{\times}10^{15}-2.93{\times}10^{17}\;cm^{-3}$, resistivity in the range of 131.2-2.864 ${\Omega}cm$, and mobility in the range of $3.99-31.6\;cm^2V^{-1}s^{-1}$ respectively.

• East Asian mathematical journal
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• 제24권3호
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• pp.233-249
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• 2008

We present new fixed point theorems for inward and weakly inward Urysohn type maps. Also we discuss $M{\ddot{o}}nch$ Kakutani and contractive type maps.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제33회 춘계학술대회 개최
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• pp.313-318
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• 2001

The sliding wear behavior of Plasma-Sprayed Al$_2$O$_3$-TiO$_2$ Coating against Cemented Carbide were Investigated using a pin on disk type tester. The experiment was conducted using Al$_2$O$_3$-TiO$_2$ Coaling as pin material and Cemented Carbide as disk material and different operating conditions, at room temperature under a dry conditions. The results showed that the type B(250kw power) appeared average wear rate Is lowed than type A(80kw power). The specific wear rate of Specimen A1 Increased with normal load. But The specific wear rate of Specimen B1 decreased with normal load. Average wear rate of specimen A3, B3 are lowed than other but the sliding wear mechanism of edge were rough.

• 한국응용과학기술학회지
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• 제24권4호
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• pp.377-382
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• 2007

We designed capacitance sensor in order to examine characteristics of W/O type emulsified fuel, so it concluded the following conclusions. The capacitance value of emulsified fuel, using with capacitance sensor, increases as water content increases due to the coalescence. When surfactant increases, the capacitance value decreases, the condition of W/O type emulsified fuel was maintained stably. There was revealed the capacitance value difference of W/O type emulsified fuel in in according to water content. We checked the phase separation of emulsified fuel with the capacitance value difference. The surfactant(HLB=5.4) had better stable condition than surfactant(HLB=4.3). Also, we confirmed that two mixture surfactants were better than one surfactant.