• Journal of Electrical Engineering and Technology
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• 제10권4호
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• pp.1759-1764
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• 2015

Glow corona is a kind of streamer-free corona that can suppress upward leaders in transmission lines. Thus, it has good application potential in lightning protection. This paper investigates its corona characteristics. The suppression characteristic of glow corona on streamer is studied in air gap under negative DC voltage by wrapping thin wires on the electrode. The effect of thin wire winding patterns on the gap breakdown voltage is analyzed. Results are considered to be attributed to the inception condition of glow corona. Thus an inception test of glow corona is also conducted, and the inception voltage is obtained. Results show that the inception voltage decreases with short winding pitch. Thus an investigation on the inception of glow corona influenced by thin wire is conducted, and an influential factor is proposed to evaluate the influence. The inception regular of thin wire glow corona presented in this paper has certain reference value for the application of glow corona in transmission lines.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 I
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• pp.341-348
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• 2001

In this study, nonlinear vibration analysis of the cylindrical orthotropic porous thin plate under V-shaped tension distribution with wire impact damping is considered. We make dynamic model of the plate under the tension using commercial FEM code and reduce the number of its degrees of freedom using dynamic condensation. The dynamic model of wire is obtained as lumped mass model from string equation. And then we analyze the nonlinear vibration of the plate including the impact phenomenon between the plate and the wire using the reduced mass and stiffness matrices of the plate and lumped model of the wire. The contact phenomenon between them can be described by impact contact elements composed of contact stiffness coefficients from Hertzian contact theory and contact damping coefficients from restitution coefficient between them. And we discussed the results of nonlinear vibration analysis for variations of their design parameters.

• Transactions on Electrical and Electronic Materials
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• 제14권1호
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• pp.20-23
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• 2013

When applying superconducting wire to power machines, an investigation needs to be carried out on the characteristics of wire phase changes in connection with the insulating layer. This study examined trends in the increase of the wire's resistance and the characteristics of its recovery from quenching by a current-applied cycle at temperatures of 90 K, 180 K, and 250 K. The procedure was conducted based on the thickness and presence (or absence) of the insulating wire layers. To achieve this, YBCO thin-film wires with the same critical temperatures were prepared with copper and stainless steel stabilizing layers. At levels (-one, three, and five-), with superior performance, polyimide pressure-sensitive adhesive tape was attached to the wires at a very low temperature. The eight prepared test samples were wound around the linear frames. The wire's voltage and current created from the phase change characteristics were measured at the wire's prescribed temperature, using the four-point probe method. The wire's resistance and recovery characteristics were examined for each cycle at temperatures of 90 K, 180 K, and 250 K.

• 한국재료학회지
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• 제25권7호
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• pp.358-363
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• 2015

We present an excellent detection for nitrogen monoxide (NO) gas using polycrystalline ZnO wire-like films synthesized via a simple method combined with sputtering of Zn metallic films and subsequent thermal oxidation of the sputtered Zn nanowire films in dry air. Structural and morphological characterization revealed that it would be possible to synthesize polycrystalline hexagonal wurtzite ZnO films of a wire-like nanostructure with widths of 100-150 nm and lengths of several microns by controlling the sputtering conditions. It was found from the gas sensing measurements that the ZnO wire-like thin film gas sensor showed a significantly high response, with a maximum value of 29.2 for 2 ppm NO at $200^{\circ}C$, as well as a reversible fast response to NO with a very low detection limit of 50 ppb. In addition, the ZnO wire-like thin film gas sensor also displayed an NO-selective sensing response for NO, $O_2$, $H_2$, $NH_3$, and CO gases. Our results illustrate that polycrystalline ZnO wire-like thin films are potential sensing materials for the fabrication of NO-sensitive high-performance gas sensors.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.172-175
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• 2009

n-type crystalline silicon wafers were passivated with intrinsic a-Si:H thin films on both sides using HWCVD. Minority carrier lifetime measurement was used to verify interface passivation properties between a-Si:H thin film and crystalline Si wafer. Thin film interface characteristics were investigated depending on $H_2/SiH_4$ ratio and hot wire deposition temperature. Vacuum annealing were processed after deposition a-Si:H thin films on both sides to investigate thermal effects from post process steps. We noticed the effect of interface passivation properties according to $H_2/SiH_4$ ratio and hot wire deposition temperature, and we had maximum point of minority carrier lifetime at H2/SiH4 10 ratio and $1600^{\circ}C$ wire temperature.

• 자원리싸이클링
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• 제29권4호
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• pp.67-72
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• 2020

폐구리전선의 재활용 공정은 여러 단계의 절단공정으로 피복재로부터 구리선을 분리 후 비중선별공정으로 구리선을 회수하는 방법이 사용되고 있다. 구리세선은 이후의 재활용 공정에서 손실 등의 우려가 있어 추가적인 처리가 필요하다. 이 연구에서는 볼밀처리를 통해 구리세선의 응집체를 구성하여 손실을 방지하고자 하였다. 구리선의 응집은 구리선이 휘어져 서로 얽히는 과정에서 발생하므로 본 연구에서는 볼밀처리 후 구리전선의 굴곡도를 측정하였다. 0.5 cm와 3 cm의 구리세선을 사용하였을 때 볼의 투입과 상관없이 0.5 cm 구리세선은 휘지 않았고, 3 cm의 구리세선은 모두 응집되었다. 1 cm와 2 cm의 구리선을 사용하였을 때는 볼을 투입하였을 때 구리선의 휨 현상이 현저하였다. 2 cm의 구리세선을 사용한 실험에서 20 mm 알루미나 볼의 투입량을 증가시킴에 따라 구리선의 응집율은 점차적으로 증가하였고 30 mm 알루미나 볼을 사용하였을 때 200 ml 투입한 경우 응집율이 89.29 %로 증가한 후 볼 투입량을 증가시키면 응집율이 감소하였다. 이와 같이 구리세선을 볼밀 처리하면 구리세선의 응집체 형성이 가능하여 구리세선의 손실이 감소될 것으로 기대된다.

• 한국전자파학회논문지
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• 제22권9호
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• pp.919-925
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• 2011

본 논문에서는 thin wire와 SRR(Split Ring Resonator)을 이용하여 유전율과 투자율을 동시에 제어할 수 있는 3D 등방성 단일 셀을 설계하고 분석해 살펴보았다. 등방성을 갖는 3D bulk 구조를 설계하기 위해서는 모든 면에서 바라본 bulk의 구조 특성이 매우 유사해야 한다. 이러한 구조를 구현하기 위하여 본 논문에서는 thin wire와 상하좌우가 모두 대칭인 SRR 구조를 설계하였으며, 이를 3D bulk 구조에 적용한 결과 8.72 GHz에서 모든 방향(x, y, z방향)에 대하여 유효 상대 유전율이 약 -0.6, 유효 상대 투자율이 약 -1.5, 그리고 굴절율이 -0.95인 3D 등방성 bulk가 설계되었다. 계산된 Brillouin 분산 다이어그램도 제안된 구조가 등방성에 유사하다는 것을 보여주었다.

• 한국소음진동공학회논문집
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• 제12권8호
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• pp.639-647
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• 2002

The nonlinear vibration of the thin perforated plate is analyzed in consideration of the V-shaped tension distribution and the effect of wire impact damping. The reduced order FEM model of the tension plate is obtained from dynamic condensation for the mass and stiffness matrices. Tension wire is modeled using the lumped parameter method to effectively describe its contact interactions with the plate. The nonlinear contact-impact model is composed of spring and damper elements, of which parameters are determined from the Hertzian contact theory and the restitution coefficient, respectively. From the evaluation of the computational accuracy and computation time for the deduced impact stiffness and damping coefficient, we determined proper values for the simulation works, accounting for the computational accuracy as well as the computational efficiency. Finally we discussed the results of nonlinear nitration analysis for variations of their design parameters.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.190-190
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• 2010

The resistance and recovery properties of the YBCO thin-film wire according to the existence and thickness of an insulting layer, and the kinds of stabilization layers, were analyzed at 90 K, 180 K and 250 K. In this study, YBCO thin-film wires with different stabilizing layers and with insulating layers were examined in terms of their various characteristics, such as quenching occurrence, spread, and distribution, based on their resistance increase trends and their recovery from quenching, and the results were qualitatively explained. The results of this study on the characteristics of YBCO thin-film wires' superconducting and normal-conducting phase changes are expected to be useful in designing superconducting power machines and in improving their performance.

• Current Photovoltaic Research
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• 제1권1호
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• pp.27-32
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• 2013

We investigated the growth mechanism of amorphous-phase Si thin films in order to improve the film characteristics and circumvent photo-degradation effects by implementation of hot-wire chemical vapor deposition. Amorphous silicon thin films grown in a silane/hydrogen mixture can be decomposed by a resistive heat filament. The structural properties were observed by Raman spectroscopy, FTIR, SEM, and TEM. The electrical properties of the films were measured by photo-conductivity, dark-conductivity, and photo-sensitivity. The contents of Si-H and $Si-H_n$ bonds were measured to be 19.79 and 9.96% respectively, at a hydrogen flow rate of 5.5 sccm, respectively. The thin film has photo-sensitivity of $2.2{\times}10^5$ without a crystalline volume fraction. The catalyst behavior of the hot-wire to decompose the chemical precursors by an electron tunneling effect depends strongly on the hydrogen mixture rate and an amorphous Si thin film is formed from atomic relaxation.