• 한국세라믹학회지
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• 제59권
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• pp.338-349
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• 2020

Large scale with high-purity hexagonal aluminum nitride nanoparticles (AlN NPs) was synthesized using DC thermal plasma arc discharge method (TPAD). Argon gas was used as the plasma forming gas, while ammonia (NH₃) gas was used as the reactive gas, which was fed into the reactor at a constant flow rate of 5 LPM. In order to optimize the process for high yield, the experiments were carried out at various plasma input powers, such as 1.5, 3.0, and 4.5 kW. Following the optimization, to examine the influence of using pure nitrogen gas, an experiment was also carried out in the nitrogen ambience. The phase identification and structural determination of the synthesized NPs were carried out using XRD and Raman spectroscopic analyses. While the morphology, particle size, and elemental compositions of the synthesized NPs were observed from SEM, HRTEM, XPS, and EDX analyses. The photoluminescence response was confirmed from the PL spectrum. The PL emission peaks observed around 440 nm (2.8 eV) and 601 nm (2.07 eV), respectively, which correspond to the UV blue and red band emissions of both AlN and Al/AlN NPs. The results show that the synthesized nano-AlN NPs exhibit excellent crystallinity with a high yield of approximately 210 g/h. The current plasma technology can be regarded as a perfect potential process for developing nano-AlN powders with improved efficiency.

• 한국전기전자재료학회논문지
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• 제15권2호
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• pp.184-189
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• 2002

Carbon nitride films were grown on Si (100) substrate by a laser-electric discharge method with/without a magnetic field assistance. The magnetic field leads to vapor plume plasma expending upon the ambient arc discharge plasma area. Influence of the magnetic field has resulted in increased of a crystallite size int he films due to bombardment (heating) of Si substrates by energetic carbon and nitrogen species generated during cyclotron motion of electrons in the discharge zone. The surface morphology of the films with a deposition time of 2 hours was studied using a scanning electron microscopy (SEM). In order to determine the structural crystalline parameters, X-ray diffraction (XRD) was used to analysis the grown films.

• 동력기계공학회지
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• 제17권1호
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• pp.110-115
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• 2013

The electrochemical performance and microstructure of Al-Si, Al-Si/C was investigated as anode for lithium ion battery. The Al-Si nano composite with 5 : 1 at% ratio was prepared by arc-discharge nano powder process. However, some of problem is occurred, when Al nano composite was synthesized by this manufacturing. The oxidation film is generated around Al-Si particles for passivating processing in the manufacture. The oxidation film interrupts electrical chemistry reaction during lithium ion insertion/extraction for charge and discharge. Because of the existence the oxidation film, Al-Si first cycle capacity is very lower than other examples. Therefore, carbon synthsized by glucose ($C_6H_{12}O_6$) was conducted to remove the oxidation film covered on the composite. The results showed that the first discharge cycle capacity of Al-Si/C is improved to 113mAh/g comparing with Al-Si (18.6mAh/g). Furthermore, XRD data and TEM images indicate that $Al_4C_3$ crystalline exist in Al-Si/C composite. In addition the Si-Al anode material, in which silicon is more contained was tested by same method as above, it was investigated to check the anode capacity and morphology properties in accordance with changing content of silicon, Si-Al anode has much higher initial discharge capacity(about 500mAh/g) than anode materials based on Aluminum as well as the morphology properties is also very different with the anode based Aluminum.

• 대한공간정보학회지
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• 제17권2호
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• pp.71-79
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• 2009

본 연구에서는 격자강우량과 격자기반의 GIS수문 매개변수와 연계하여 홍수기 유출량의 시공간적 분포를 파악할 수 있도록 물리적인 운동파 이론에 근거한 분포형 강우-유출모형인 K-DRUM을 자체 개발하였다. 이 모형은 홍수 기동안의 지표흐름과 지표하 흐름의 시간적 변화와 공간적 분포를 모의할 수 있으며, 전처리과정으로서 ArcView 를 이용하여 모형에 필요한 ASCII형태의 입력 매개변수 자료들을 가공하였다. 또한 후처리과정으로서 모형의 수행결과인 유역내의 유출량 분포 등을 GIS상에서 나타낼 수 있도록 ASCII형태로 출력하도록 구성하였으며 TecPlot 을 이용하여 유출량을 에니메이션으로 표현하였다. 또한, 유출량에 가장 큰 영향을 미치는 초기토양함수 상태에 대한 자동보정기법을 추가 개발하였으며, 남강댐유역을 대상으로 기저유출해석을 수행하여 개발된 자동보정기법의 활용가능성을 검토하였다. K-DRUM모형의 초기토양함수조건을 설정하는데 있어서 자동보정기법을 적용함으로써 기존의 시행착오법으로 인해 소요되는 시간과 부정확한 설정으로 발생될 수 있는 문제점을 해결할 수 있었다.

• 반도체디스플레이기술학회지
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• 제2권1호
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• pp.1-5
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• 2003

Plasma generator based on non-self-sustained low-pressure arc discharge has been examined as a tool for deposition of highly-adhesive hydrogenated amorphous diamond-like carbon(DLC) films. Since the discharge is stable in wide range of gas pressures and currents, this plasma source makes possible to realize both plasma-immersion ion implantation(PIII) and plasma-immersion ion deposition(PIID) in a unified vacuum cycle. The plasma parameters were measured as functions of discharge current. Discharge and substrate bias voltage parameters have been determined for the PIII and PIID modes. For PIID it has been demonstrated that hard and well-adherent DLC coating are produced at 200-500 eV energies per deposited carbon atom. The growth rates of DLC films in this case are about 200-300 nm/h. It was also shown that short(∼60$\mu\textrm{s}$) high-voltage(> 1kV) substrate bias pulses are the most favorable for achieving high hardness and good adhesion of DLC, as well as for reducing of residual intrinsic stress are.

• 전기의세계
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• 제22권2호
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• pp.57-69
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• 1973

The aim of this study was to investigate the behaviors of plasma jet under coaxial magnetic field in paralled with it for controlling optical characteristics and input power of plasma jet without impurity and instability of arc plasma column. Because the discharge characteristics of plasma jet were so distinctively different according to the existence or non-existence of magnetic field, the input power, luminous intensity of plasma jet and thermal efficiency were comparatively studied in respect of such variables as arc current, gap of electrode, quantity of argon flow, magnetic flux density, diameter and length of nozzle, with the use of several materials which were different in diameter and length of nozzel. The results were as follows; 1) The voltage tends to show a drooping characteristic at law current and then rises gradually. The luminous intensity of plasma jet increases exponentially with arc current. 2) Arc voltage increases and luminous intensity tends to decrease gradually as gap of electrode increases. 3) Arc voltage and luminous intensity tends to decrease gradually as gap of electrode increases. 3) Arc voltage and luminous intensity increase in accordance with the quantity of argon flow. 4) At first step, arc voltage increases to maximum value with the growth of flux density and then tends to show a gradual decrease. Luminous intensity decreases with the growth flux density. 5) Arc voltage decreases as the constriction length of nozzle increases, maximum decrease is shown at the constriction length of 20(mm) and it increases beyond that value. The luminous intensity decreases as the constriction length grows. 6) Arc voltage and luminous in tensity increase with the growth of diameters of nozzle. 7) Thermal efficiency has values between 50% and 75%, being influenced by arc current, the quantity of argon flow, flux density, the length of electrode gap and the constriction length of nozzle.

• 스마트미디어저널
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• 제9권1호
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• pp.38-44
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• 2020

전기에너지에 대한 높은 의존도 때문에 국내에서 발생하는 화재 중 전기화재가 상당한 비중을 차지한다. 국내에서 발생하는 전기화재 4건 중 3건이 전선의 단락이나 접촉 불량에 의한 전기 아크에 의해 발생했다. 전기 아크란 절연체 사이에서 발생하는 전기적 전류의 방전 현상으로 순간적으로 상당한 열을 내뿜는다. 아크에 의한 전기 화재를 줄이기 위해서 본 연구에서는 전기 아크 위험성 예측을 목표로 한다. 아크 감지기에서 아크 데이터를 수집하고 시간순대로의 아크 데이터를 기반으로 그래프로 변환하였다. 머신 러닝의 데이터 학습에 서로 다른 시계열 데이터의 수로 변환한 그래프들을 사용하였다. 생성된 학습 모델의 성능을 측정하기 위해서 테스트 데이터를 기반으로 평가를 진행하였다. 결과에서 예측 시 사용하는 시계열 아크 데이터의 수가 20개일 때 예측률이 86%로 우수함을 확인하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.74-77
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• 2000

Today there is an ever increasing effort to control high-pressure discharge lamps with electronic ballast. HID lamps can be ignited by high-voltage pulses and need an ignitor to start them. An ignitor gives high-voltage pulses to HID lamps which have the type of the arc discharge. Three kinds of ignitor circuits have been analyzed by the P-spice program and we have shown experimental results in this paper. The result of this study seems to be able to help to develope various ignitors.

• 산업기술연구
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• 제18권
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• pp.157-163
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• 1998

Today there is an ever increasing effort to control high-pressure discharge lamps with electronic ballasts. HID lamps can be ignited by high-voltage pulses and need an ignitor to start them. An ignitor gives high-voltage pulses to HID lamps, which have the type of the arc discharge. Two kinds of ignitor circuits have been analyzed by the P-spice program and we have shown experimental results in this paper. The result of this study seems to be able to help to develope various ignitors.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.814-816
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• 2002

Because there is a strong interaction between the arc discharge and their surroundings, it is not easy to predict the characteristics of industrial arc plasma systems such as gas circuit breakers. The design procedure of these systems is still largely based on trial and error, although the situation is rapidly improving because of the available computational power at a cost in which is still coming down. The desire to predict the behavior of arc plasma systems, thus optimizing and reducing the develpment cost, has been the motivation of these arc researches. In this paper. we have simulated the switching operation of a gas circuit breaker during high current area using a computational fluid dynamics considered the electric field analysis, the radiation model and the effeects of turbulence.