• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.480-480
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• 2011

양극산화(anodization)는 금속을 전기화학적으로 산화시켜 금속산화물로 만드는 기술로서 최근 다양한 크기의 나노 구조를 제조하는 기술로 각광받고 있으며, 이러한 기술에 의하여 얻어지는 anodic aluminum oxide(AAO)는 magnetic data storage, optoelectronic device, sensor에 적용될 수 있는 nano device 뿐만 아니라 nanostructure를 제조하기 위한 template 및 mask로써 최근 광범위 하게 연구되고 있다. 또한, AAO는 Al2O3의 단단한 구조를 가진 무기재료이므로 solid mask로써 다른 porous materials 보다 뛰어난 특성을 갖고 있다. 또한 electron-beam lithography 및 block co-polymer 에 의한 patterning 과 비교하여 매우 경제적이며, 재현성이 우수할 뿐만 아니라 대면적에서 나노 구조의 크기 및 형상제어가 비교적 쉽기 때문에 널리 사용되고 있다. 그러나, AAO 형성 시 생기게 되는 반구형 모양의 barrier layer는 물질(substance)과 기판과의 direct physical and electrical contact을 방해하기 때문에 해결해야 할 가장 큰 문제점 중 하나로 알려져 있다. 따라서 본 연구에서는 실리콘 기판위의 형성된 AAO의 barrier layer를 Cl/BCl3 gas mixture에서 Neutral Beam Etching (NBE)과 Ion Beam Etching (IBE) 로 각각 식각한 후 그 결과와 비교하였다. NBE와 IBE 모두 Cl2/BCl3 gas mixture에서 BCl3 gas의 첨가량이 60% 일 경우 etch rate이 가장 높게 나타났고, optical emission spectroscopy (OES)로 Cl2/BCl3 플라즈마 내의 Cl radical density와 X-ray photoelectron spectroscopy (XPS)로 AAO 표면 위를 관찰한 결과 휘발성 BOxCly의 형성이 AAO 식각에 크게 관여함을 확인 할 수 있었다. 또한, NBE와 IBE 실험한 다양한 Cl2/BCl3 gas mixture ratio 에서 AAO가 식각이 되지만, 이온빔의 경우 나노사이즈의 AAO pore의 charging에 의해 pore 아래쪽의 위치한 barrier layer를 어떤 식각조건에서도 제거하지 못하였다. 하지만, NBE에서는 BCl3-rich Cl2/BCl3 gas mixture인 식각조건에서 AAO pore에 휘발성 BOxCly를 형성하면서 barrier layer를 제거할 수 있었다.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.19 no.2
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• pp.267-270
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• 2021

Long-term experiments have been conducted on two important safety issues: long-term durability of a concrete barrier with the steel reinforcements and gas generation from low-and intermediate-level wastes in an underground research tunnel of a radioactive waste disposal facility. The gas generation and microbial communities were monitored from waste packages (200 L and 320 L) containing simulated dry active wastes. In the concrete experiment, corrosion sensors were installed on the steel reinforcements which were embedded 10 cm below the surface of concrete in a concrete mock-up, and groundwater was fed into the mock-up at a pressure of 2.1 bars to accelerate groundwater infiltration. No clear evidence was observed with respect to corrosion initiation of the steel reinforcement for 4 years of operation. This is attributed to the high integrity and low hydraulic conductivity of the concrete. In the gas generation experiment, significant levels of gas generation were not measured for 4 years. These experiments are expected to be conducted for a period of more than 10 years.

• Journal of Korean Vacuum Science & Technology
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• v.1 no.1
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• pp.30-37
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• 1997

Interactions of Cu films with Si substrates separated by thin layers of molybdenum and molybdenum nitride were investigated in the viewpoint of diffusion barrier to copper. the diffusion barrier behavior of the layers was studied as functions of deposition and annealing conditions by cross-sectional transmission electron microscopy and Nomarski microscopy. the layers deposited at $N_2$ gas ratios of 0.4 and 0.5 exhibited good diffusion barrier behaviors up to $700^{\circ}C$, mainly due to the phase transformation of molybdenum to $\gamma$-Mo$_2$N phase. The increase in the N gas ratio in deposition elevates the lower limit of barrier failure temperature. Futhermore, amorphous molybdenum nitride films deposited at 20$0^{\circ}C$ and 30$0^{\circ}C$ did not fail, while the crystalline $\gamma$-Mo$_2$N films deposited at 40$0^{\circ}C$ and 50$0^{\circ}C$ showed signs of interlayer interactions between Cu and Si after annealing at 75$0^{\circ}C$ for 30 minutes. Therefore, the amorphous nature of the molybdenum nitride layer enhanced its ability to reduce Cu diffusion and its stability as a diffusion barrier at elevated temperatures.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1897-1899
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• 2003

본 논문에서는 Barrier coupler type UHF 센서의 현장적용 및 감도개선을 위해 외부잡음의 차폐방법과 광대역 안테나를 Barrier coupler type UHF센서에 적용시켜 센서의 성능을 개선시켰다. GIS 내부에서 발생하는 부분방전 신호를 검출하기 위하여 UHF대역(0.3${\sim}$3GHz)의 전자파 신호의 검출이 가능한 광대역 Rectangular 패치 안테나를 barrier coupler type UHF 센서에 적응 설계하였으며, Rectangular patch antenna를 배열(array) 했을 때의 특성들을 비교하였다. 이론 위해 상용화된 EM Simulator를 이용하여 센서의 방향성과 감도 특성을 검토하여 설계 및 제작하였다. 개발된 센서의 실제 특성을 분석하기 위해서 network analyzer로 센서의 특성을 분석하였고, 실규모의 GIS 챔버를 사용하여 다양한 결함에 대한 센서의 감도와 특성을 평가하였다. 본 연구의 결과로서 제작된 barrier coupler type UHF센서가 가스절연기기(GIS)의 부 부방전 신호를 검출할수 있음을 입증하였고, 광대역 외장형센서의 경우 patch antenna의 구조에 크게 상관하지 않음을 알 수 있었다. 향후에는 GIS 내장형 센서와 비교 연구론 통해 barrier coupler type 센서의 성능을 개선하고자 한다.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.1
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• pp.15-20
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• 2014

Thermal barrier coating (TBC) is used to protect the substrate and extend the operating life of the gas turbine for a power plant and an aircraft. The major cause of failure of such a coating is the spallation of coating, and it results from the thermal stress between top coating and bond coating. To improve the durability of TBC system, the dense vertical cracked (DVC) coating method to insert vertical cracks is applied to a gas turbine blade. In this study, a criterion for the design of vertical crack in the DVC coating was presented using the finite element analysis.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.465-465
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• 2012

In this study, we developed an Al2O3 nanolaminated single gas barrier layer using a Neutral Beam Assisted Sputtering (NBAS) process. The NBAS process can continuously change crystalline structures from an amorphous phase to a nanocrystal phase with various grain sizes and lead to the formation of a nanolaminated structure in the single inorganic thin film. As a result, the water vapor transmission rates (WVTR) of the nanolaminated Al2O3 thin films by NBAS process have improved more than 40% compared with that of conventional Al2O3 layers by the RF magnetron sputtering process under the same sputtering conditions.

• Polymer(Korea)
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• v.37 no.6
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• pp.770-776
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• 2013

The ENR 50 having the lowest gas permeability was blended with Nylon 6 which exhibits superior gas permeability, excellent wear resistance by using a twin-screw extruder. The blended materials showed the increased gas barrier property and physical properties, but did not yield a great synergistic effect due to low dispersion of Nylon 6 to ENR 50. To improve dispersion of Nylon 6 in the rubber matrix, maleic anhydride (MAH) was grafted to ENR 50. The grafting reaction between MAH and ENR 50 was evidenced using IR spectroscopy. The grafted and blended materials, ENR 50- g-MAH/Nylon 6 compounds, resulted in an enhanced gas barrier property and physical properties compared with compounds without MAH. The compound at 5 phr of MAH showed the highest crosslinking density and the best performances.

• Journal of Environmental Science International
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• v.27 no.8
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• pp.621-629
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• 2018

Many chemically active species such as ${\cdot}H$, ${\cdot}OH$, $O_3$, $H_2O_2$, hydrated $e^-$, as well as ultraviolet rays, are produced by Dielectric Barrier Discharge (DBD) plasma in water and are widely use to remove non-biodegradable materials and deactivate microorganisms. As the plasma gas containing chemically active species that is generated from the plasma reaction has a short lifetime and low solubility in water, increasing the dissolution rate of this gas is an important challenge. To this end, the plasma gas and water within reactor were mixed using the air-automizing nozzle, and then, water-gas mixture was injected into water. The dissolving effect of plasma gas was indirectly confirmed by measuring the RNO (N-Dimethyl-4-nitrosoaniline, indicator of the formation of OH radical) solution. The plasma system consisted of an oxygen generator, a high-voltage power supply, a plasma generator and a liquid-gas mixing reactor. Experiments were conducted to examine the effects of location of air-automizing nozzle, flow rate of plasma gas, water circulation rate, and high-voltage on RNO degradation. The experimental results showed that the RNO removal efficiency of the air-automizing nozzle is 29.8% higher than the conventional diffuser. The nozzle position from water surface was not considered to be a major factor in the design and operation of the plasma reactor. The plasma gas flow rate and water circulation rate with the highest RNO removal rate were 3.5 L/min and 1.5 L/min, respectively. The ratio of the plasma gas flow rate to the water circulation rate for obtaining an RNO removal rate of over 95% was 1.67 ~ 4.00.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.163-166
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• 1998

The mechanism of methane sensing by Pd-SiC diode was investigated over the temperature range of 400~$600^{\circ}C$. The effects or methane gas reaction on the parameters such as barrier height, initial rate of methane gas reaction are investigated. The methane gas reaction kinetics on the device are also discussed. The physical and chemical mechanism responsible for methane detection are proposed. Analysis of steady-state reaction kinetics using I-V method confirmed that methane gas reaction processes are responsible for the barrier height change in the diode.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.633-636
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• 2006

GE has developed a plastic substrate technology comprised of a superior high-heat polycarbonate substrate film and a unique transparent coating package that provides the ultrahigh barrier to moisture and oxygen, and chemical resistance to solvents used in device fabrication. This contribution will update recent progresses made at GEFlexible Ultra-high Gas Barrier Substrate for Organic Electronics on ultra-high barrier coated plastic substrate, both in batch mode and in roll-to-roll mode