• Title, Summary, Keyword: Electric field

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Analysis on Electric Field Based on Three Dimensional Atmospheric Electric Field Apparatus

  • Xing, Hong-yan;He, Gui-xian;Ji, Xin-yuan
    • Journal of Electrical Engineering and Technology
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    • v.13 no.4
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    • pp.1697-1704
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    • 2018
  • As a key component of lighting location system (LLS) for lightning warning, the atmospheric electric field measuring is required to have high accuracy. The Conventional methods of the existent electric field measurement meter can only detect the vertical component of the atmospheric electric field, which cannot acquire the realistic electric field in the thunderstorm. This paper proposed a three dimensional (3D) electric field system for atmospheric electric field measurement, which is capable of three orthogonal directions in X, Y, Z, measuring. By analyzing the relationship between the electric field and the relative permittivity of ground surface, the permittivity is calculated, and an efficiency 3D measurement model is derived. On this basis, a three-dimensional electric field sensor and a permittivity sensor are adopted to detect the spatial electric field. Moreover, the elevation and azimuth of the detected target are calculated, which reveal the location information of the target. Experimental results show that the proposed 3D electric field meter has satisfactory sensitivity to the three components of electric field. Additionally, several observation results in the fair and thunderstorm weather have been presented.

Development of a Method for Improving the Electric Field Distribution in Patients Undergoing Tumor-Treating Fields Therapy

  • Sung, Jiwon;Seo, Jaehyeon;Jo, Yunhui;Yoon, Myonggeun;Hwang, Sang-Gu;Kim, Eun Ho
    • Journal of the Korean Physical Society
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    • v.73 no.10
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    • pp.1577-1583
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    • 2018
  • Tumor-treating fields therapy involves placing pads onto the patient's skin to create a low- intensity (1 - 3 V/cm), intermediate frequency (100 - 300 kHz), alternating electric field to treat cancerous tumors. This new treatment modality has been approved by the Food and Drug Administration in the USA to treat patients with both newly diagnosed and recurrent glioblastoma. To deliver the prescribed electric field intensity to the tumor while minimizing exposure of organs at risk, we developed an optimization method for the electric field distribution in the body and compared the electric field distribution in the body before and after application of this optimization algorithm. To determine the electric field distribution in the body before optimization, we applied the same electric potential to all pairs of electric pads located on opposite sides of models. We subsequently adjusted the intensity of the electric field to each pair of pads to optimize the electric field distribution in the body, resulting in the prescribed electric field intensity to the tumor while minimizing electric fields at organs at risk. A comparison of the electric field distribution within the body before and after optimization showed that application of the optimization algorithm delivered a therapeutically effective electric field to the tumor while minimizing the average and the maximum field strength applied to organs at risk. Use of this optimization algorithm when planning tumor-treating fields therapy should maintain or increase the intensity of the electric field applied to the tumor while minimizing the intensity of the electric field applied to organs at risk. This would enhance the effectiveness of tumor-treating fields therapy while reducing dangerous side effects.

A study on conduction current and D.C. breakdown characteristics in dielectric liquids (절연유의 도전전류와 직류절연파괴특성에 관한 연구)

  • 서국철
    • 전기의세계
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    • v.30 no.4
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    • pp.231-236
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    • 1981
  • It has been known that D.C. breakdown Voltage is lower than A.C. breakdown Voltage in insulatingoil, but there are still many unvivid points at electric conduction in breakdown or under of high electric field. This study measured the electric current-electric field characteristics (I-E characteristics) and the breakdown Voltage under of D.C. electric field of insulating oil using the system of electrodes that are near the Uniform electric field with a result. I can study, electric conduction in area of high electric field depends upon the Schottky effect. The liquidity of breakdown electric field takes place by the local concentration of electric field. The longer gap is and the more electric current is the more breakdown Voltage decreased. There are not almost the change of electric current-electric field characteristics by materials of electrode.

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An Experimental Study on the Effect of Electric Field the Ornithine Decarboxylase Activity Change of Myeloid Cells According to Ionizing Radiation Exposure (이온화방사선 피폭에 의한 골수세포의 Ornithine Decarboxylase 활성도의 변화에 대한 전계장의 영향에 관한 실험적 연구)

  • 정문호
    • Journal of Environmental Health Sciences
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    • v.21 no.1
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    • pp.78-85
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    • 1995
  • Ornithine decarboxylase(ODC) is an indicate enzyme in carcinogenesis. We divided Sprague Dawley rats into six groups: control, electric field exposure, X-ray only irradiation, X-ray irradiation with electric field exposure group, Sr-90 injected group and Sr-90 and electric field complex exposure group. The ODC activity was measured in rat's bone marrow cell every week. The results were summarized as follows: The ODC activitied was increased in X-ray irradiated, Sr-90 injected and Sr-90 and electric field complex exposed group as compared with that of control(p<0.05). The ODC activity was increased comparing that of control neither in X-ray and electric field complex exposed group nor electric field only exposed group. This result suggests that the electric field doesn't have myeloid carcinogenicity and myeloid cancer incidence caused by ionized radiation is suppressed by electric field exposure.

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Measurement and Analysis of the Atmospheric Electric Field using Balloon-Carried E-Field Sensor (비양기구로 운반되는 전계센서를 이용한 대기전계의 측정과 분석)

  • Kim, Seung-Min;Lee, Bok-Hee
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.30 no.2
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    • pp.78-84
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    • 2016
  • This paper is focused on the measurement and analysis of an atmospheric electric field which is caused by thunderclouds. The electric field due to thunderclouds changes very slowly. For this reason, the extremely low frequency E-field sensor needs to be used for measuring the atmospheric electric field strength. The balloon-carried E-field sensor system with the time constant of 1sec was designed and fabricated. The electric field sensor consists of $100mm{\times}100mm$ copper plate, active integrator, high pass and low pass filters and batteries. The measurements of atmospheric electric fields were made by the balloon-carried E-field sensor and radiosonde, which sends the data back to ground in real time. From the calibration experiments, the response sensitivity of the E-field sensor was 0.154mV/kV/m in the frequency range of less than 1kHz. As a result from the actual experiment of the atmospheric electric field, the electric field signals were observed from the altitude of about 2.5km. Also, as the altitude was increased, the detected electric field wave oscillated with the fluctuation of sensing plate. The proposed method seems suitable for measurements of atmospheric electric fields, because it is inexpensive, simple to use and launch.

Effect of PMMA Content on the Crystallization of PEO/PMMA Blends Under an External Electric Field (PMMA 함량이 외부전장 하에서 결정화되는 PEO/PMMA 블렌드물의 결정화에 미치는 영향)

  • 김영호;홍성돈;김갑진
    • Textile Science and Engineering
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    • v.40 no.5
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    • pp.408-415
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    • 2003
  • The effects of an external electric field and poly(methyl methacrylate) (PMMA) content on the crystallization of poly(ethylene oxide)(PEO)/PMMA blends were investigated using a polarizing microscope equipped with a hot stage and an external electric field supplier. The crystallization of PEO was strongly affected by the external electric field; i.e., the induction period increased and the crystallization rate decreased with the strength of the electric field. Since the magnitude of electric field effect was enormous, it was difficult to estimate the exact extent of the influence of the electric field on the crystallization of PEO, especially when the applied voltage was over 40 kV/cm. Blending PMMA with PEO decreased the crystallization rate of PEO and the influence of the electric field. Thus, it was possible to investigate the influence of the electric field over a wide range. The total crystallization rate of PEO in PEO/PMMA blends decreased as the strength of the external electric field increased. Because of the electro-inactivity of PMMA, the influence became progressively smaller as PMMA content increased. At higher PMMA contents, stronger electric field was needed to affect crystallization rates significantly.

The Effect of External DC Electric Field on the Atmospheric Corrosion Behaviour of Zinc under a Thin Electrolyte Layer

  • Liang, Qinqin;YanYang, YanYang;Zhang, Junxi;Yuan, Xujie;Chen, Qimeng
    • Corrosion Science and Technology
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    • v.17 no.2
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    • pp.54-59
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    • 2018
  • The effect of external DC electric field on atmospheric corrosion behavior of zinc under a thin electrolyte layer (TEL) was investigated by measuring open circuit potential (OCP), cathodic polarization curve, and electrochemical impedance spectroscopy (EIS). Results of OCP vs. time curves indicated that the application of external DC electric field resulted in a negative shift of OCP of zinc. Results of cathodic polarization curves measurement and EIS measurement showed that the reduction current of oxygen increased while charge transfer resistance ($R_{ct}$) decreased under the external DC electric field. Variation of OCP negative shift, reduction current of oxygen, and $R_{ct}$ increase with increasing of external DC electric field strength as well as the effect of external DC electric field on double-layer structure in the electrode/electrolyte interface and ions distribution in thin electrolyte layer were analyzed. All results showed that the external DC electric field could accelerate the corrosion of zinc under a thin electrolyte layer.

A Study on the Disinfection of Coliform Group in the Effluent of Sewage Plant by High Voltage Electric Field Treatment (고전압 전기장을 이용한 하수처리장 방류수 중의 대장균군 소독에 관한 연구)

  • Lee, Min-Gyu;Chung, Geun-Sik;Kam, Sang-Kyu
    • Journal of Environmental Science International
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    • v.17 no.7
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    • pp.817-826
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    • 2008
  • Using high voltage electric fields induced by high voltage AC (10-12 kV/cm, 20 kHz) and pulsed (20-30 kV/cm, 40 Hz) electric field generator as a semipermanent and environment-friendly disinfecting apparatus, the disinfection effect of coliform group in the effluent of sewage plant was investigated. The effects of electric field strength, treatment time, discharge area of a discharge tube, water quality factors (electric conductivity, pH and SS) on its death rate were examined. The death rate of coliform group was increased with increasing electric field strength and treatment time. For AC and pulsed electric field generator, the critical electric field strength was 6 kV/cm and 2 kV/cm, respectively, and the critical treatment time was 5 min and 2 min, respectively, regardless of electric field strength. Comparing the death rate of coliform group by AC and pulsed electric fields used in this study, its death rate was higher for the latter than the former, but did not increase linearly with increasing electric field strength. The results obtained for the effects of discharge area, electric conductivity, pH and SS on the death rate of coliform group using AC electric field (12 kV/cm, 20 kHz) were as follows: its death rate showed the trend to increase linearly with increasing discharge area; for the effect of electric conductivity, its death rate was increased with increasing electric conductivity, regardless of ionic species, increased with increasing cationic valency, but was similar between the same cationic valency; the pH $5{\sim}9$ used in this study did not affect its death rate; its death rate was decreased with increasing SS concentration.

Computer simulation of electric field distribution in FALC process (FALC 공정에서의 전계 분포 전산모사)

  • 정찬엽;최덕균;정용재
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.13 no.2
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    • pp.93-97
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    • 2003
  • The crystallization behavior of amorphous silicon is affected by direction and intensity of electric field in FALC(Field-Aided Lateral Crystallization). Electric field was calculated in a simplified model using conductivity data of Mo, a-Si, $SiO_2$and boundary conditions for electric potential at the electrodes. The magnitude of electric field intensity in each corner of cathode was much larger than that in the center of patterns, and the electric field direction was 50~60 degree outside to cathode. And electric field intensity at a relatively small pattern was larger than that of a large pattern.

Analysis of Electric Field Distribution according to Surface Roughness of Aramid Insulating Paper Using Boundary Element Method (경계요소법을 이용한 표면 거침도에 따른 아라미드 절연지의 전계분포 해석)

  • Kim, Tag-Yong;Ahn, Byung-Chul;Cho, Kyung-Soon;Park, Hyung-Jun;Hong, Jin-Woong
    • Journal of the Korean Society of Safety
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    • v.21 no.5
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    • pp.34-39
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    • 2006
  • In this paper, we investigated the electric field distribution according to the roughness in aramid insulating paper for electric machine. Aramid insulating paper has been used to electric insulating of the traction motor and generators for large capacity. We studied the electric field distribution using boundary element method for Aramid insulating paper. As a result of simulation, the electric field increased according to the surface roughness existence. Electric field decreased due to radius of surface roughness reduction, and Electric field concentration appeared at electrode boundary and rough surface.