• Annals of Clinical Neurophysiology
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• v.13 no.1
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• pp.26-30
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• 2011

Although the pathophysiologic mechanism is unknown, there has been long-running debate on whether periodic discharges such as periodic lateralized epileptiform discharges (PLEDs) and generalized periodic epileptiform discharges are an ictal or interictal EEG pattern. The goal of this review is to give evidence that such periodic discharges on EEG are not ictal phenomenon and just represent underlying acute brain damage. This review includes coma with epileptiform EEG pattern and its prognostic and therapeutic implications. Based on previous reports, rather than taking the view PLEDs represent either an underlying ictal process or an electrographic correlate of neuronal injury, it would be more reasonable that PLEDs are considered as a dynamic pathophysiological state in which unstable neurobiological processes create an ictal-interictal continuum.

• Annals of Clinical Neurophysiology
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• v.13 no.1
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• pp.21-25
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• 2011

Periodic lateralized epileptiform discharges (PLEDs) had been debated whether it is ictal or non-ictal phenomenon. As most of PLEDs occur in patients with acute structural lesions, some epileptologists prefer PLEDS as a non-ictal phenomenon, rather an obscure epiphenomenon of etiological diseases. But, almost half of the patients with PLEDs do not have acute structural lesions in the brain and metabolic disorders or old CNS lesions may cause PLEDs and even more, no brain lesion was identified in some patients. There are many data supporting PLEDs as ictal phenomena. Occurrence of PLEDs usually accompanied by decreased mentality and is improved as PLEDs disappeared. Current SPECT study showed marked hyperperfusion in the lesion side of PLEDs, that is striking evidence of PLEDs as ictal phenomena. Also careful review of EEG with PLEDs revealed it is a dynamic process rather than a static state. Despite of these evidences, as PLEDs are an end-stage of animal status epilepticus models, it may be a transition of ictal to interictal state.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.130-130
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• 2015

플라즈마를 이용한 cleaning, etching, sputtering 공정에서 발생하는 마이크로아크방전이나 turn-off후의 잔류정전기는 공정대상물의 절연파괴나 전자소자에 전기적 손상을 유발함으로서 공정의 불량률을 증가시키는 중요한 요인이 된다. 본 연구에서는 잔류정전기를 관찰하기위하여 실린더형 챔버구조의 평행평판 전극구조를 지닌 용량결합형 플라즈마에서 powered electrode에 부착된 유전체 기판 표면의 잔류 정전기의 변화 양상을 planar type probe로 측정해보았다. 300mtorr 압력에서 아르곤가스로 발생시킨 플라즈마가 존재할 때 낮은 음전위 평균값을 가지던 기판표면 전위가 전력인가가 중지되었을때 20V 가량의 양전위를 가질 수 있음을 측정 하였고, 이것을 COMSOL MULTIPHYSICS TOOL을 활용한 시뮬레이션과 비교하였다. 이 현상이 파워인가 전극이 플라즈마 영역에 노출되느냐에 따라 발생할 수 있음을 알게 되었고, 그 크기와 지속시간은 입력전력 및 블로킹 커패시터와 유전체 기판의 정전용량에 의존함을 확인 하였다.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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• 2002.02a
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• pp.114-118
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• 2002

This paper were investigated discharge characteristics in the Liquid Nitrogen($LN_{2}$) noticed as a cooling medium of high temperature superconductor, and the characteristics of surface discharge and tracking phenomena on the solid insulators of cryocable. In order to investigate the bubbles which have much influence on electric surface discharge in Liquid Nitrogen, knife type electrode and plane electrode was formed oppositely with mode A and B, C configuration. It is considered that these result are fundamental data for electric insulation design of superconductivity and cryogenic application machinery which will be studied and developed in the future.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.10a
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• pp.30.2-30.2
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• 2011

나노 채널 구조는 반응 물질의 빠른 확산 경로를 제공하고, 넓은 반응 활성화 면적을 가지므로, 센서, 촉매, 전지 등의 다양한 기능성 전기 화학 소자용 고효율 전극 구조로서 관심을 받고 있다. 최근 양극 산화법을 이용하여, 자가 배열된 나노 채널 구조의 주석 산화물을 형성시키는 연구가 진행되고 있다. 그러나, 기재위에 도금된 주석 박막이 양극 산화에 의해 산화물로 변화하는 과정에서 내부 균열 및 표면 기공의 막힘 현상이 관찰되고, 기재 위 주석의 산화가 완료되는 시점에서는 기재의 산화 및 산소 발생에 의한 기계적 충격 등으로 인해 산화물이 기재로부터 탈리되는 문제가 발생하여, 그 응용 연구가 크게 제한되어 있는 실정이다. 본 연구에서는 다공성 주석 산화물 합성 시의 구조적 결함이 나타나는 이유에 대해 체계적으로 분석하고, 이를 바탕으로 결함이 없는 나노 채널 주석 산화물을 제조하는 방법을 제시하였다. 또한, 주석 산화물 박막을 기능성 전기화학 소자용 전극 활물질, 특히 리튬 전지용 음극재료로 사용하기 위한 효과적인 전극 제조 방법에 대해 논의하고, 그에 따라 제조된 전극의 충방전 용량, 사이클링 안정성 등을 제시하였다.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2320-2322
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• 1999

This paper was studied on the surface discharge characteristics and tracking phenomena on the solid insulator in liquid nitrogen ($LN_2$) at atmospheric pressure. In order to investigate the bubbles which have much influence on electric surface discharge in liquid nitrogen, Knife type electrode and plane electrode were arranged in different modes(Mode A, Mode B, and Mode C) and investigated for surface discharge and tracking phenomena. In Mode A, by the movement of bubbles tracking damage was formed under the electrodes. The tracking pattern in Mode B was formed along the electrode axis.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.05a
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• pp.279-282
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• 2005

Morden electronic equipments are becoming very important in information oriented society, but they are vulnerable to lightning surges. Soil resistivity in the vicinity of grounding electrodes my be affected by the current flowing from the grounding electrodes into the surrounding soil. Electrical conduction in soils depends on the grain size, compactness, and variability of the grain sizes. When a high current is injected into the soil, and the breakdown phenomenon occur. In the present work, Electrical behaviors related to discharge in soils were investigated. The breakdown voltages in soil were lower than that sparkover voltage in air. The breakdown voltage in the gravel layer is relatively low, and the breakdown was caused by the flashover through the surface of gravels

• Journal of Korean Society for Atmospheric Environment
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• v.17 no.2
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• pp.223-231
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• 2001

In order to provide some insights into the influence of electric field, gas composition, and gas temperature on electron energy distribution and electron transport characteristics, the Boltzmann equation was solved by using cross section data for electron collisions, Critical electric fields for the corona development in dry air and flue gas are 150 and 80 Td, respectively. It was seen that the decrease of critical electric field in flue gas is mainly caused by the $H_2O$ addition through the comparison of ionization and attachment coefficients of gas components. Increase of $O_2$, $H_2O$, and $CO_2$ contents in gas affected discharge characteristics according to their reciprocal characteristics between lowering the ionization threshold and increasing the electro-negativity. As electric field increases, electrons with higher energies in the electron energy distribution also increase. The mean and characteristic electron energies also linearly increase with electric field. The variation of flue gas temperature did rarely affect on the electron energy distribution function and electron transport characteristics, because the gas temperature is several hundreds or thousands times lower than the electron temperature.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.2
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• pp.65-71
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• 2001

This paper describes partial discharge phenomenon with SF6gas pressures in insulation consisting of insulation paper and SF6 gas. We made the specimens with SF6 gas gaps which exist between aramid papers and electrodes and calculated the electric field intensity in the these gaps. We measured the partial discharge inception voltages and the AC breakdown voltages with the test method of IEC 60060-2 and did the partial discharge degradation experiments with a constant voltage. According to gas pressures, the breakdown voltages in SF6gas gaps were calculated by Paschen's law. And these results showed the ability applying partial discharge inception voltages evaluation to Paschen's law and the relationship between the PD quantities occurring insulation breakdown and PD occurring area.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.1489-1491
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• 2004

PD in air is accompanied by light, sound and electromagnetic wave. Light and sound can be prevented from blocking between PD sources and sensor but electromagnetic wave can be transferred to long distance without any interference an captured by antenna. This paper investigated the wideband antenna is appropriate for sensing Partial discharge in air. PD was generated from simulated PD source which consist of needle and flat electrode with small gap. Signals obtained from wideband antenna were diminished in both time and frequence region with the distance between PD source and antenna.