• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.480-480
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• 2007

A large diameter plasma filled backward wave oscillator is investigated experimentally. The parameters of slow wave structure are chosen so that the oscillation frequency is high beam energy. Plasma is produced by the beam and it has favorable effects on beam propagation and Cerenkov oscillation.

• 대한전자공학회논문지
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• 제5권3호
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• pp.31-39
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• 1968

외부자계가 가해진 냉프라즈마에서의 마이크로파 전파 특성을 측정하였다. 직류방전프라즈마는 두 전극판을 구형도파관에 삽입한것과, 또한 유리시설관을 구형도파관에 삽입한 것에서 이루어졌다. 마이크로파 전파방향, 방전관축, 외부자계는 각각 수직이고, 자속밀도, 방전유기, 기체압등이 증가할때 프라즈마를 전파하는 마이크로파의 감쇠 및 흡수는 증가함을 보았다.

• 한국광학회:학술대회논문집
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• 한국광학회 2002년도 하계학술발표회
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• pp.240-241
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• 2002

Propagation of an intense laser pulse through fully ionized plasma has been an interesting topic in many fields. It includes laser-driven electron accelerators,(1) generation of high harmonics,(2) soft x-ray laser development(3) and so on. Specifically, in the application of laser-driven electron accelerators a large laser-plasma interaction length is required to get sufficient acceleration energy of electron. (omitted)

• 화약ㆍ발파
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• 제17권2호
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• pp.19-35
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• 1999

Rock fragmentation with plasma blasting technique has advantageous properties in contrast to the conventional blasting method controlling of flying rocks and ground vibrations, when residents are complaining or surrounding structures stay in protection from blasting operations. The experiences show in urban construction works that the plasma blasting is the most possible method to prevent damages and minimize adverse environmental impacts. The fragmentation energy level is evaluated by numerical simulation using PFC for various drill hole patterns and tested accordingly to get the feasibility. The energy output of plasma blasting system has been improved to a level of 1 MJ, which can break a 2-3 ㎥ granite boulder or 1.5m height bench face. Measurements are carried out to get the ground vibration level and propagation equation, so that control of the blasting operations can be performed more precisely and safely.

• 터널과지하공간
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• 제7권4호
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• pp.267-273
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• 1997

Rock fragmentation with plasma blasting technique has advantageous properties in contrast to the conventional blasting method in controlling of flying rocks and ground vibrations, when residents are complaining or surrounding structures stay in protection from blasting operations. The experiences show in urban construction works that the plasma blasting is the most possible method to prevent damages and minimize adverse environmnetal impacts. The fragmentation energy level is evaluated by numerical simulation using PFC-2D for various drill hole pattern and tested accordingly to get the feasibility. The energy output of plasma blasting system has been improved to a level of 1 MJ, which can break a 2~3 ㎥ granite boulder or 1.5 m height bench face. Measurements are carried out to get the ground vibration level and propagation equation, so that the control of the blasting operations can be performed more precisely and safely.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.59-63
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• 2003

Modal properties of guided waves along circular dispersive double negative (DNG) index metamaterial rod waveguides are numerically investigated. Identical forms of dispersive dielectric and magnetic material constants are used for simplicity. For degenerated azimuthally symmetric mode, a multimode region, a single mode region, a band gap region and a forbidden region are found which cannot be observed in the case of the conventional dielectric rod waveguide. As the normalized frequency goes down, discrete guided modes are continuously generated, which is a reverse property of conventional dielectric rod waveguide. Also, there are high-frequency cutoffs, which have been generally examined in dispersive circular geometries such as a plasma column or a plasma Goubau line. In the single mode region, both the low- and high-frequency cutoffs are existed where the propagation constants are continued between the guided oscillating and surface modes.

• 화약ㆍ발파
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• 제17권1호
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• pp.19-26
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• 1999

Rock fragmentation with plasma blasting technique has advantageous properties in contrast to the conventional blasting method in controlling of flying rocks and ground vibrations when residents are complaining or surrounding structures stay in protection from blasting operations. The experiences show in urban construction works that the plasma blasting is the most possible method to prevent damages and minimize adverse environmental impacts. The fragmentation energy level is evaluated by numerical simulation using PFC for various drill hole pattern and tested accordingly to get the feasibility. The energy output of plasma blasting system has been improved to a level of 1 MJ, which can break a $2-3m^3$ granite boulder or 1.5m height bench face. Measurements are carried out to get the ground vibration level and propagation equation. So that the control of the blasting operations can be performed more precisely and safely.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권7호
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• pp.424-432
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• 2000

The plasma surface treatment, using hydrogen gas, of the silicon wafer was investigated as a pretreatment for the application to silicon-on-insulator (SOI) wafers using the silicon direct bonding technique. The chemical reactions of hydrogen plasma with surfaces were used for both the surface activation and the removal of surface contaminants. As a result of exposure of silicon wafer to the plasma, an active oxide layer was formed on the surface, which was rendered hydrophilic. The surface roughness and morphology were estimated as functions of plasma exposing time as well as of power. The surface became smoother with decreased incident hydrogen ion flux by reducing plasma exposing time and power. This process was very effective to reduce the carbon contaminants on the silicon surface, which was responsible for a high initial surface energy. The initial surface energy measured by the crack propagation method was 506 mJ/m2, which was up to about three times higher than that of a conventional RCA cleaning method.

• Journal of Astronomy and Space Sciences
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• 제34권4호
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• pp.343-352
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• 2017

A space plasma facility has been operated with a back-diffusion-type plasma source installed in a mid-sized vacuum chamber with a diameter of ~1.5 m located in Satellite Technology Research Center (SaTReC), Korea Advanced Institute of Science and Technology (KAIST). To generate plasma with a temperature and density similar to the ionospheric plasma, nickel wires coated with carbonate solution were used as filaments that emit thermal electrons, and the accelerated thermal electrons emitted from the heated wires collide with the neutral gas to form plasma inside the chamber. By using a disk-type Langmuir probe installed inside the vacuum chamber, the generation of plasma similar to the space environment was validated. The characteristics of the plasma according to the grid and plate anode voltages were investigated. The grid voltage of the plasma source is realized as a suitable parameter for manipulating the electron density, while the plate voltage is suitable for adjusting the electron temperature. A simple physical model based on the collision cross-section of electron impact on nitrogen molecule was established to explain the plasma generation mechanism.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2001년도 춘계학술강연 및 발표대회
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• pp.35-35
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• 2001