• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2000년도 하계학술대회 논문집 B
• /
• pp.828-830
• /
• 2000

This paper describes BIEM(Boundary Integral Equation Method) for computation of three dimensional electric field distribution and numerical method that an equivalent charge density is unknown variable. After computing numerically the surface charge distribution. the distribution of both potential and electric field are obtained. Finally, this numerical method is applied to the concentric sphere and the coaxial cylindrical model and numerical result is compared to the analytic solution.

• Journal of Electrical Engineering and Technology
• /
• 제9권2호
• /
• pp.655-661
• /
• 2014

In this paper, a new two dimensional (2D) analytical modeling and simulation for a surrounding gate tunnel field effect transistor (TFET) is proposed. The Parabolic approximation technique is used to solve the 2-D Poisson equation with suitable boundary conditions and analytical expressions for surface potential and electric field are derived. This electric field distribution is further used to calculate the tunneling generation rate and thus we numerically extract the tunneling current. The results show a significant improvement in on-current characteristics while short channel effects are greatly reduced. Effectiveness of the proposed model has been confirmed by comparing the analytical results with the TCAD simulation results.

• Interaction and multiscale mechanics
• /
• 제3권2호
• /
• pp.157-171
• /
• 2010

In this paper, a theoretical method has been developed for the electric double layer interaction under condition of the variable dielectric permittivity of water. Using Poisson-Boltzmann equation (PBE), for one plate and two plates having similar or dissimilar constant charge or constant potential, we have investigated the electric double layer potential, its gradient and the disjoining pressure as well as the effect of variation of dielectric permittivity on these parameters. It has been assumed that plates are separated by a specific distance and contain a liquid solution in between. It is shown that reduction of the dielectric permittivity near the interfaces results in compression of electric double layers and affects the potential and its gradient which leads to a decreased electrostatic repulsion. In addition, it is shown that variation of dielectric permittivity in the case of higher electrolyte concentration, leads to a greater change in potential distribution between two plates.

• Smart Structures and Systems
• /
• 제9권2호
• /
• pp.127-143
• /
• 2012

The present paper deals with the nonlinear analysis of the functionally graded piezoelectric (FGP) annular plate with two smart layers as sensor and actuator. The normal pressure is applied on the plate. The geometric nonlinearity is considered in the strain-displacement equations based on Von-Karman assumption. The problem is symmetric due to symmetric loading, boundary conditions and material properties. The radial and transverse displacements are supposed as two dominant components of displacement. The constitutive equations are derived for two sections of the plate, individually. Total energy of the system is evaluated for elastic solid and piezoelectric sections in terms of two components of displacement and electric potential. The response of the system can be obtained using minimization of the energy of system with respect to amplitude of displacements and electric potential. The distribution of all material properties is considered as power function along the thickness direction. Displacement-load and electric potential-load curves verify the nonlinearity nature of the problem. The response of the linear analysis is investigated and compared with those results obtained using the nonlinear analysis. This comparison justifies the necessity of a nonlinear analysis. The distribution of the displacements and electric potential in terms of non homogenous index indicates that these curves converge for small value of piezoelectric thickness with respect to elastic solid thickness.

• 전기학회논문지
• /
• 제58권11호
• /
• pp.2229-2235
• /
• 2009

In this paper, each specimen blended at weight proportions of 80% HDPE to 20% EVA, 70% HDPE to 30% EVA, 60% HDPE to 40% EVA, and 50% HDPE to 50% EVA was manufactured respectively. The insulation performances of the proposed insulator were compared with conventional XLPE, main insulating material of CV cable on the basis of the investigation results of DC insulation performances. From the space charge density, electric field and potential profiles with raising DC voltage and time variation in HE82, distortion of electric field distribution was improved. As EVA mixed into the bulks acts as nucleation in crystallization process of HDPE, the size of spherulites became decreased and finally formed continuous network structure. Ultimately, it resulted from extinction of space charge in the interfacial region of spherulites.

• 대한전자공학회논문지SD
• /
• 제39권4호
• /
• pp.10-18
• /
• 2002

본 논문에서는 IPS모드의 액정 셀에서 전압에 따른 액정 거동을 수치 해석적으로 계산하는 방법을 보고한다. 액정 거동을 해석하기 위해 복잡한 구조에 적용이 용이한 3차원 유한 요소법을 사용하여 액정 셀 내부의 전압 분포와 전계 분포를 계산하였다. 전기 에너지와 액정 분자의 탄성 에너지로 이루어지는 액정 셀 내부의 자유에너지 밀도를 고려하였으며, 에릭슨-레슬리(Ericksen-Leslie) 방정식과 라플라스(Laplace) 방정식을 해석함으로서 액정 셀의 스위칭 특성을 계산하였다. 24㎛×12㎛×4.5㎛ 사이즈의 IPS 모드 액정 셀에 대하여 1,859개의 노드와 8,640개의 사면체 요소를 생성하여 16ms까지 과도 해석하였다. 그 결과, 전극 위 부분을 제외한 영역에서 횡방향의 전계가 형성되었고, 전극 위 영역에서 전경선(disclination)이 발생하는 것을 확인하였다.

• Journal of the Korean Physical Society
• /
• 제73권10호
• /
• pp.1577-1583
• /
• 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.

• 조명전기설비학회논문지
• /
• 제21권6호
• /
• pp.71-76
• /
• 2007

본 논문에서는 상용전원이 침수되었을 경우, 이에 의한 인체 감전의 위험성을 실증실험을 통해 검토하였다. 실험을 위해 한쪽 벽면에 노출된 충전부가 설치된 모의수조를 구축하고 내부에 도전성 수용액을 채운 후, 전원으로부터의 거리, 방향, 도전성 수용액의 전도율 및 수위에 따른 전위를 측정하였다. 실험 결과 수중에 설치된 전원장치로 인한 전위분포는 거리에 따라 달라지지만, 침수 수용액의 도전율, 노출된 충전부로부터의 각도 및 측정높이는 전기적으로 미치는 영향이 거의 없음이 확인되었다.

• 한국산학기술학회논문지
• /
• 제12권11호
• /
• pp.5123-5127
• /
• 2011

증가 추세인 지중 전력설비의 사고 예방과 유지 보수를 위한 기술 연구 개발 요구가 증가하고 있다. 지중선로의 경우 누전 불량의 점유율이 높고 보수도 어려워 정확한 누전점 위치의 탐지가 중요하다. 교류 송신파를 누전점을 가지는 지중선로에 인가하여 발생시킨 교류 대지전위를 측정하여 누전점의 위치를 찾는 방법은 송신파 특정 극성반주기에 교류 대지전위를 동기화하여 비교 판단하여야 한다. 송신파의 특정 극성의 반주기와 동기화하는 기존 방법을 설명하고, 송신파 반주기 변조된 대지 전위 측정 방식을 제안하고 소개하였다. 실험을 통하여 제안한 방식이 구현 가능함을 확인하였다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 하계학술대회 논문집 A
• /
• pp.79-82
• /
• 1999

So far, The methods for identifying the parameters of some region or material have been developed. This paper describes a new method for electric resistivity reconstruction using multi-resolution property of wavelet. The outputs of the potential electrodes are computed using two dimensional FEM in the wave number space by Fourier transforming the governing equation. The resistance distribution in the region of interests, which makes the computed potential distribution coincide with the measured potential, is found by minimizing the objective function using an optimization method. Multi-resolution analysis introduced in this paper will be proved to be the proper method in the viewpoint of effectivity and time-consuming by the numerical results.