• Title, Summary, Keyword: Electrostatics

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Three Dimensional Medical Image Rendering Using Laplace's Equation (라플라스 방정식의 해를 이용한 삼차원 의학 영상 랜더링)

  • Kim, S.M.;Ahn, C.B.
    • Proceedings of the KIEE Conference
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    • pp.2918-2920
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    • 2000
  • A new multi-planar interpolation technique for three dimensional medical image rendering is proposed. In medical imaging. resolution in the slice direction is usually much lower than those in the transverse planes. The proposed method is based on the solution of the Laplace's equation used in the electrostatics. In this approach. two contours in the source and destination planes for a given object is assumed to have equi-potentials. Some preprocessing and post-processing including scaling. displacement. rotation from the centers of mass are involved in the algorithm. The interpolation solution assumes mostly smoothing changes in between the source and destination planes. Simultaneous multiple interpolation planes are inherently obtained in the proposed method. Some experimental and simulation results are shown.

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Spray and Depositional Characteristics of Electrostatics Nozzle for Spraying Agricultural Chemicals (정전대전 농약살포용 노즐의 분무 및 부착특성)

  • 강태경;이동현;이채식;김충길;노수영
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • pp.156-161
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    • 2003
  • 농약과 방제기가 개발되면서 적은 노력과 비용으로 넓은 면적의 작물을 병과 해충으로부터 보호할 수 있게 되어 수확량이 대폭 늘어나고 농사도 안정적으로 지을 수 있게 되었다. 이렇게 방제작업이 손쉽게 되었으나 농약을 필요량보다 적게 뿌릴 경우 병해충을 충분히 방제할 수 없고, 많이 뿌릴 경우 비용과 환경오염을 증가시키는 또 다른 문제점에 부닥치게 되었다. 현재 사용되고 있는 방제기로 농약을 살포할 경우 노출된 작물의 잎에서는 농약이 흘러내리는 반면 수관내부에 감추어진 잎이나 병해충이 주로 발생되는 잎 뒷면은 농약 부착이 미흡하다. (중략)

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Meshfree Local Radial Basis Function Collocation Method with Image Nodes

  • Baek, Seung Ki;Kim, Minjae
    • Journal of the Korean Physical Society
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    • v.71 no.1
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    • pp.1-7
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    • 2017
  • We numerically solve two-dimensional heat diffusion problems by using a simple variant of the meshfree local radial-basis function (RBF) collocation method. The main idea is to include an additional set of sample nodes outside the problem domain, similarly to the method of images in electrostatics, to perform collocation on the domain boundaries. We can thereby take into account the temperature profile as well as its gradients specified by boundary conditions at the same time, which holds true even for a node where two or more boundaries meet with different boundary conditions. We argue that the image method is computationally efficient when combined with the local RBF collocation method, whereas the addition of image nodes becomes very costly in case of the global collocation. We apply our modified method to a benchmark test of a boundary value problem, and find that this simple modification reduces the maximum error from the analytic solution significantly. The reduction is small for an initial value problem with simpler boundary conditions. We observe increased numerical instability, which has to be compensated for by a sufficient number of sample nodes and/or more careful parameter choices for time integration.

Improvement of a Coulomb's Law Apparatus for Student Use

  • Kim, Chung-Sik
    • New Physics: Sae Mulli
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    • v.67 no.8
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    • pp.1016-1022
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    • 2017
  • The improvement of a Coulomb's law apparatus for student use is described. The conventional apparatus, which measures the displacement of a suspended charged ball repelled by a fixed charged ball, has long been used in physics education, but has a disadvantage in that setting the separation between the balls is difficult. The improvement is achieved by adding an inclined device to make the suspended ball return to the equilibrium position. This allows both the repulsive force to be derived from the tangent of the inclination and the separation between the two balls to be set easily. The setup is installed in an enclosure with a transparent cover and a desiccant inside in order to minimize the effect of humidity. Results obtained from the improved apparatus show that the force follows an inverse square law with an exponent $n=-1.99{\pm}0.01$ and is proportional to the product of charges, in agreement with Coulomb's law.

Analysis of Transport Characteristics for FinFET Using Three Dimension Poisson's Equation

  • Jung, Hak-Kee;Han, Ji-Hyeong
    • Journal of information and communication convergence engineering
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    • v.7 no.3
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    • pp.361-365
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    • 2009
  • This paper has been presented the transport characteristics of FinFET using the analytical potential model based on the Poisson's equation in subthreshold and threshold region. The threshold voltage is the most important factor of device design since threshold voltage decides ON/OFF of transistor. We have investigated the variations of threshold voltage and drain induced barrier lowing according to the variation of geometry such as the length, width and thickness of channel. The analytical potential model derived from the three dimensional Poisson's equation has been used since the channel electrostatics under threshold and subthreshold region is governed by the Poisson's equation. The appropriate boundary conditions for source/drain and gates has been also used to solve analytically the three dimensional Poisson's equation. Since the model is validated by comparing with the three dimensional numerical simulation, the subthreshold current is derived from this potential model. The threshold voltage is obtained from calculating the front gate bias when the drain current is $10^{-6}A$.

Comparison study of the future logic device candidates for under 7nm era

  • Park, Junsung
    • Proceeding of EDISON Challenge
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    • pp.295-298
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    • 2016
  • Future logic device over the FinFET generation requires a complete electrostatics and transport characteristic for low-power and high-speed operation as extremely scaled devices. Silicon, Germanium and III-V based nanowire-based MOSFET devices and few-layer TMDC (Transition metal dichalcogenide monolayers) based multi-gate devices have been brought attention from device engineers due to those excellent electrostatic and novel device characteristic. In this study, we simulated ultrascaled Si/Ge/InAs gate-all-around nanowire MOSFET and MoS2 TMDC based DG MOSFET and TFET device by tight-binding NEGF method. As a result, we can find promising candidates of the future logic device of each channel material and device structures.

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Theoretical and Experimental Analysis of Back-Gated SOI MOSFETs and Back-Floating NVRAMs

  • Avci, Uygar;Kumar, Arvind;Tiwari, Sandip
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.4 no.1
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    • pp.18-26
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    • 2004
  • Back-gated silicon-on-insulator MOSFET -a threshold-voltage adjustable device-employs a constant back-gate potential to terminate source-drain electric fields and to provide carrier confinement in the channel. This suppresses shortchannel effects of nano-scale and of high drain biases, while allowing a means to threshold voltage control. We report here a theoretical analysis of this geometry to identify its natural length scales, and correlate the theoretical results with experimental device measurements. We also analyze experimental electrical characteristics for misaligned back-gate geometries to evaluate the influence on transport behavior from the device electrostatics due to the structure and position of the back-gate. The backgate structure also operates as a floating-gate nonvolatile memory (NVRAM) when the back-gate is floating. We summarize experimental and theoretical results that show the nano-scale scaling advantages of this structure over the traditional front floating-gate NVRAM.

Analysis of Characteristics on the Static Electricity by Streaming Electrification (유동대전에 의한 정전기 특성 분석)

  • Kim, Gil-Tae;Lee, Jae-Keun
    • Journal of the Korean Society of Safety
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    • v.20 no.3
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    • pp.42-46
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    • 2005
  • The static electricity by thinner flow and discharge energy is investigated experimentally for the purpose of preventing the electrostatic discharge and damage. Test system for evaluating streaming electrification consists of a teflon pipe, a reservoir tank a pump, flowmeters and an electrometer. When dielectric liquid flows through a pipe from one vessel to another, the potential difference generated in the collecting vessel is due to the accumulation of charges. These charges result from the convection of a part of the electrical double layer existing in the tube at the contact between the liquid and the inner wall. When the fluid velocity increases, the electric current increases proportionally. The charging current and accumulated charges by streaming electrification at the thinner velocity of 40cm/s are measured a range of 5 nA and $0.27{\mu}C$ respectively. This amount of static discharge energy generated by streaming electrification is enough to ignite flammable solvent. Therefore surface electric potential should decrease by using electrostatic shielding and ground.

A Study for Development and Characteristics of Electrostatic Eliminator for Charged Particles (대전된 분체의 정전기제거장치 개발 및 특성에 관한 연구)

  • Jung, Yong-Chul;Kim, Joon-Sam;Lee, Dong-Hoon
    • Journal of the Korean Society of Safety
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    • v.21 no.3
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    • pp.22-30
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    • 2006
  • On this study, we developed the electrostatic eliminator for charged particles in manufacturing process. The characteristics of the electrostatic eliminator were investigated, which is two kinds. The first one is Electrical Corona Discharged Type Ionizer. The second one is Photo Ionizer in using soft X-ray. From the experiment, we have obtained the following results. In case of Electrical Corona Discharged Ionizer, neutralization efficiency of charged particles were approximately saturated to 98% over 6.0kV, but as it is non-explosion proof, can not be used in flammable particle treatment process. While in case of photo Ionizer in using soft X-Ray, neutralization efficiency of charged particles were approximately 95%, and more its structure is explosion proof, could be used in flammable particle treatment process.

A Study on the Oxygen Saturation Level Changes in the Blood Exposed to the Static Magnetic Field (자속에 노출된 인체의 혈중 산소 포화농도의 변화에 관한 연구)

  • Jung, Yong-Chul;Lee, Dong-Hoon
    • Journal of the Korean Society of Safety
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    • v.22 no.6
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    • pp.87-90
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    • 2007
  • The effects of static magnetic field on the human biological system are becoming increasingly more important with the adaption of static magnet in the medical community. It is the goal of this paper to review the effects of static magnetic fields on oxygen saturation level in blood. The results of this paper show that the oxygen saturation level increased in the blood in index finger when the static magnetic dipole was fitted on index finger.