• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2002.10a
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• pp.281-284
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• 2002

Geographic Information System (GIS) has advantage of analyzing spatial distributed data and handling spatial data for hydrologic analysis. Hydrologic Engineering Center's Hydrologic Modeling System(HEC-HMS) with HEC-GeoHMS was used to analyze flood runoff at agricultural small watershed. HEC-GeoHMS, which is an ArcView GIS extension designed to process geospatial data for HEC-HMS, is a useful tool for storing, managing, analyzing, and displaying spatially distributed data. Hydroligical component including peak discharge, time to peak, direct runoff, baseflow for Balhan study watershed, which is located in Whasung city, Kyunggi province, having an area of $29.79km^2$, were calculated using the HEC-HMS model with HEC-GeoHMS.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1560-1563
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• 1987

This paper is concerned with time delay modeling of ED MOS gates which takes into account the slope of input waveform as well as the load condition. Defining the delay time as the time required to charge/discharge the load to the physical reference level, the rise/fall delay times arc derived in an explicit formula in terms of the sum of optimally weighted current unbalances at two end points of voltage transition. The proposed model is computationally effective and the error is typically within 10% of the SPICE results.

• Proceedings of the Korea Crystallographic Association Conference
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• 2000.11a
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• pp.21-21
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• 2000

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1233-1234
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• 2006

A simple new method to fabricate transparent carbon nanotube field emission devices was developed. The highly graphitized single wall carbon nanotubes were attached on Sn/ITO glass by arc discharge method. Post heat treatments below the deformation temperature of soda-lime glass guaranteed a good mechanical adhesion and electrical contact of the nanotubes. The Sn layer was oxidized below $400^{\circ}C$ and became transparent. As increasing the oxidation temperatures, the emission properties became stable and life time of emitter has been increased.

• Nuclear Engineering and Technology
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• v.44 no.1
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• pp.9-20
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• 2012

A brief review on the thermal plasma synthesis of nano-sized powders is presented according to the application materials, such as, metals, ceramics, glasses, carbonaceous materials and other functional composites, such as, supported metal catalyst and core-shell structured nano materials. As widely adopted plasma sources available for thermal plasma synthesis of nanosized powders, three kinds of plasma torches, such as transferred and non-transferred DC and RF plasma torches, are introduced with the main features of each torch system. In the basis of the described torch features and the properties of suggested materials, application results including synthesis mechanism are reviewed in this paper.

• Journal of the Korean Society for Heat Treatment
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• v.13 no.5
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• pp.318-323
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• 2000

The planarization of rough polycrystalline diamond films synthesized by DC arc discharge plasma jet CVD (chemical vapor deposition) was attempted using KrF excimer laser pulses. The effects of laser incidence angle and reaction gases (ozone and oxygen) on etching rate of diamond were studied. The temperature change of diamond and graphite with different laser fluences was calculated by computer simulation to explain the etching behavior of diamond films. The threshold energy density from the experiment for etching of pure crystalline diamond was about $1.7J/cm^2$ and fairly matched the simulation value. Preferential etching of a particular crystallographic plane was observed through scanning electron microscopy. The etching rate of diamond with ozone was lower than that with oxygen. When the angle of incidence was $80^{\circ}$ to the diamond surface normal, the peak-to-valley surface roughness was Significantly reduced from $20{\mu}m$ to $0.5{\mu}m$.

• Carbon letters
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• v.14 no.3
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• pp.131-144
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• 2013

The carbon nanotube (CNT) represents one of the most unique inventions in the field of nanotechnology. CNTs have been studied closely over the last two decades by many researchers around the world due to their great potential in different fields. CNTs are rolled graphene with $SP^2$ hybridization. The important aspects of CNTs are their light weight, small size with a high aspect ratio, good tensile strength, and good conducting characteristics, which make them useful as fillers in different materials such as polymers, metallic surfaces and ceramics. CNTs also have potential applications in the field of nanotechnology, nanomedicine, transistors, actuators, sensors, membranes, and capacitors. There are various techniques which can be used for the synthesis of CNTs. These include the arc-discharge method, chemical vaporize deposition (CVD), the laser ablation method, and the sol gel method. CNTs can be single-walled, double-walled and multi-walled. CNTs have unique mechanical, electrical and optical properties, all of which have been extensively studied. The present review is focused on the synthesis, functionalization, properties and applications of CNTs. The toxic effect of CNTs is also presented in a summarized form.

• Proceedings of the Korea Contents Association Conference
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• 2017.05a
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• pp.253-254
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• 2017

미연탄소의 함유량이 많은 플라이애시를 사용한 시멘트의 경우 공기량이 저하되며, 슬럼프의 확보를 위해 AE제와 같은 혼화제의 사용을 요구한다. 이러한 미연탄소를 제거하기 위해 저온 플라즈마를 이용한 표면 개질에 관한 연구가 진행되었으나, $O_2$를 사용하는 플라즈마의 경우 $O_3$를 생성하는 문제가 발생한다. 따라서 본 연구에서는 플라즈마를 대신에 아크방전을 이용하여 플라이애시 내의 미연탄소를 제거해 표면을 개질하는 기술에 관한 기초적 연구를 진행하였다. 그 결과, 아크방전을 통해 플라이애시의 표면을 개질할 시 플라이애시의 물리적 특성이 개선되며, 이를 이용한 시멘트경화체의 강도도 향상되는 것을 알 수 있었다.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.201-201
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• 2012

Using materials with high thermal conductivity is a matter of great concern in the field of thermal management. In this study, we present our experimental results on an important physical property of carbon nanotube (CNT) films, two-dimensional thermal conductivity obtained by using an optical method based on Raman spectroscopy. We prepared four kinds of CNT films to investigate the effect of CNT type on heat spreading performance of films. This first comparative study using the optical method shows that the arc-discharge single-walled carbon nanotubes yield the best heat spreading film. And we observed thermal conductivity values of CNT films with various transmittances and found that the Raman method works as long as the sample is a transparent film. This study provides useful information on characterization of thermal conduction in transparent CNT films and could be an important step toward high-performance carbon-based heat spreading films.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.490-490
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• 2012

Ballast capacitor에 저장된 에너지로 방전 에너지를 조절할 수 있는 방전장치를 개발하였다. 본 연구에서는 ballast capacitor의 용량을 조절하여 micro-size의 아크 플라즈마를 발생시켰으며, 용량변화에 따른 플라즈마의 온도를 측정하였다. 또한 ICCD camera를 이용하여 ballast capacitor의 용량변화에 따른 cathode의 변화를 관찰하였다. Optical Emission Spectroscopy를 통하여 플라즈마의 광학적 특성을 분석하였다. 마이크로 아크 방전의 주파수를 높이기 위하여 switching device를 병렬로 연결하여 아크 플라즈마를 구동시켰으며, 발생된 마이크로 아크 플라즈마는 정밀방전 가공에 응용되었다. 본 연구는 2011년도 지식경제부의 재원으로 한국에너지 기술평가원(KETEP)의 지원을 받아 수행한 연구 과제입니다(No. 20104010100670).