• 전기학회논문지
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• 제57권2호
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• pp.314-319
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• 2008

In this paper, the electric field distribution induced inside the brain during Transcranial Magnetic Stimulation(TMS) has been thoroughly investigated in terms of tissue heterogeneity and anisotropy as well as different head models. To achieve this, first, an elaborate head model consisting of seven major parts of the head has been built based on the Magnetic Resonance(MR) image data. Then the Finite Element Method(FEM) has been used to evaluate the electric field distribution under different head models or three different conductivity conditions when the head model has been exposed to a time varying magnetic field achieved by utilizing the Figure-Of-Eight(FOE) stimulation coil. The results show that the magnitude as well as the distribution of the induced field is significantly affected by the degree of geometrical asymmetry of head models and conductivity conditions with respect to the center of the FOE coil.

• 전기학회논문지
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• 제56권2호
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• pp.282-288
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• 2007

Magnetization loss of high temperature superconductoring BSCCO tape and YBCO coated conductor(YBCOCC) is most important issue in the development of superconducting power devices. In this paper, the measured results of magnetization losses under various angles of external magnetic field in BSCCO tape stacked conductors and YBCO CC stacked conductors are presented and compared with each other. Also, we present the compared results of magnetization losses measured at arbitrary reaction magnetic fields and analyzed with perpendicular magnetic field components of those. The results show that magnetization losses of YBCO CC single and stacked conductors agree well with the analyzed value by it's perpendicular magnetic field component, but BSCCO single and stacked conductors are not.

• 전기학회논문지
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• 제56권12호
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• pp.2091-2097
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• 2007

This paper described the verification of modeling technique of underground distribution from comparison between field test and simulation. It needs more exact transient phenomenon analysis model to establish lightning protection of underground distribution line. Although, there were a lot of transient phenomenon researches, nobody could has verified the confidence of modeling from field tests in interior until now. So, simulation model verified field test is needed to analyse transient phenomenon of underground distribution system. The examination must be accomplished in many different condition before suggesting these verified analysis model. In this paper, the conditions were examined and the various data results on the different line composition was compared with the EMTP simulation, when the lightning impulse test was accomplished at underground distribution line. Also the value between field test and simulation was very closed and the method of modeling has demonstrated confidence, when the method is used to analyse domestic transient phenomenon of underground distribution.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권6호
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• pp.309-315
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• 1999

Coupling loss is generated by the time-varying external magnetic field in the normal matrix of the multi-filamentary HTS tape. This paper calculates the coupling loss in the HTS tape. Analytic calculation of the coupling loss cannot consider the effect of the different shapes and the arrangement of the filaments. Numerical calculation by using finite element method and analytic calculation of the coupling loss have been done in this paper and results of two calculations have been compared. Transverse magnetic field and longitudinal magnetic field were considered as the external field.

• 한국전기전자재료학회논문지
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• 제17권5호
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• pp.530-535
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• 2004

We have studied 90$^{\circ}$ twisted nematic mode switching by fringe electric field(F-TN mode) using a liquid crystal (LC) with negative dielectric anisotropy. In the device, two polarizers are parallel each other, electrodes exist only on bottom substrate, and one of rubbing direction is coincident with polarizer axis. Therefore, the cell shows a black state before a voltage is applied. With a bias voltage generating fringe-electric field, the LC twists perpendicular to fringe electric field such that the LCs are almost homogeneously aligned except near the bottom surface since the negative type of the LC is used. Consequently, the new device exhibits much wider viewing angle than that of the conventional TN mode due to in-plane switching and relatively high transmittance since the LC director above whole electrode area aligns parallel to the polarizer axis.

• 한국자동차공학회논문집
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• 제5권1호
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• pp.120-128
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• 1997

The variations of the temperature field in a passenger compartment were measured by using a HSI true color image processing system and TLC(Thermochromic Liquid Crystal) solution. This temperature measurement technique was proved to be useful for analyzing the ventilation flow. The flow field in the passenger compartment was visualized using a particle streak method with pulsed laser light sheet. The temperature field and flow field in the passenger copartment were affected significantly by the ventilation mode. The panel-vent mode heating had shorter elapse time to reach a uniform temperature than the foot-vent mode under the same ventilation condition and nonuniformity inside the passenger compartment could be minimized effectively by using the bilevel heating mode. The temperature increase rate in the rear passenger compartment was iower than the front compartment, especially in the vicinity of the rear seat occupants' knee level.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권10호
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• pp.471-476
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• 2005

We proposed an optical modulator of reflective type to compose the electric field sensor, and theoretically analyzed the performance and characteristics. For the high sensitivity of the sensor, a method to improve the modulation index of the modulator was presented. The electric field sensor using Ti:LiNbO$_{3}$ waveguide was fabricated and qualitatively investigated the characteristics by measuring the low frequency electric field. Even though the sensor showed relatively low modulation index, the electric filed strength of 10$^{-2}$V/m was measured. The experimental results revealed the utilities of this type electric field sensor.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권10호
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• pp.501-506
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• 2003

A Superconducting Rotary Machine (SRM) is characterized by an air-cored machine with its rotor iron and stator iron teeth removed. For this reason, the SRM is featured by 3D magnetic flux distribution, which decreases in the direction of axis. Therefore, 3D magnetic field analysis method is required to know about characteristic of magnetic field distribution of SRM. In this paper, 3D flux distribution of SRM is calculated by analytical method. The magnetic field distribution of the field coils is calculated by Biot-Savart equation. The magnetic core is represented by magnetic surface polarities. This paper describes the combined use of above methods for the total field computation, and compares results of analytical method and 3D FEM(Finite Element Method).

• 한국농공학회지
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• 제44권4호
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• pp.51-61
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• 2002

The objective of this study is to develop GLEANS-PADDY model to predict nutrients loading from paddy-field areas. This model is developed by modifying the GLEANS model which is used for uplands, and composed of hydrology and nutrient submodels. The optimal field size for CLEANS-PADDY model application is about up to 50 ha with mild slope, relatively homogeneous Soils and spatially rainfall, and a single crop farming. The CLEAMS model is modified to handle ponded soil surface condition and saturated soil profile in paddy field. In the hydrology submodel of the CLEAMS-PADDY model. the ponded depth routing method is used to handle the ponded water condition of paddy field. To compute potential evapotranspiration the FAO-24 Corrected Blaney-Criddle method is used for paddy field instead of Penman-Monteith method in the CLEAMS model. In the nutrients submodel of the CLEAMS-PADDY model, the soil was assumed saturated and soil profile in the root zone was divided into oxidized and reduced zones.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.489-490
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• 2008

This paper describes the analysis of electric field distribution of high voltage polymeric bushing with structure. The high voltage bushing consists of FRP tube and housing made of LSR. The field control can be achieved by means of the design of such internal field shaper and top corona ring as grading electrodes. In accordance, the optimized design uses both internal and external elements for electric stress grading at critical parts of the bushing. Maxwell 2D simulator based on the boundary element method was also introduced in order to verify the reliability of the polymeric bushing.