• Title/Summary/Keyword: Electrostatics

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The Effect of Interface Activation Substances in Reduction Phenomena of Streaming electrification (유동대전 감소현상에 미치는 계면활성제의 효과)

  • Kim, Y.W.;Lee, S.H.;Han, J.S.;Lee, E.H.;Lee, D.C.
    • Proceedings of the KIEE Conference
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    • 1999.07e
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    • pp.2146-2148
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    • 1999
  • The purpose of this study is to find the way to reduce the electrostatics by interface activation substances added in the insulating oil with concentration[ppm]. As results. The streaming current, surface tension and viscosity of the samples added nonionic and hermaphrodic substances are decreased but the conductivity is increased at higher point than the 1[ppm] (c.m.c.), the other side the same phenomena of the samples added cationic and anionic substances are discovered at the 10[ppm].

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A INSULATING DESIGN OF $SF_6$ GAS SEALING END OF CONDENSER CONE TYPE USED FOR 345KV OF CABLE (콘덴서 콘 방식의 345KV OF 케이블용 $SF_6$ 가스중 종단접속함의 절연 설계)

  • Kim, H.J.;Lee, S.C.;Oh, O.J.;Lee, H.S.
    • Proceedings of the KIEE Conference
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    • 1994.07b
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    • pp.1553-1555
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    • 1994
  • In this paper, we describes the research in condenser cone of $SF_6$ gas sealing end for 345KV oil-filled cable. The designed of condenser cone based on the results electric field analysis by electrostatics theory ana FEM. As a results. we have been designed the condenser cone and the inner insulation part of $SF_6$ seating end, the width and length, the number of condenser, the length of stress relief slope, the total length of condenser cone.

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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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    • 2000.07d
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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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A hybrid CSS and PSO algorithm for optimal design of structures

  • Kaveh, A.;Talatahari, S.
    • Structural Engineering and Mechanics
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    • v.42 no.6
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    • pp.783-797
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    • 2012
  • A new hybrid meta-heuristic optimization algorithm is presented for design of structures. The algorithm is based on the concepts of the charged system search (CSS) and the particle swarm optimization (PSO) algorithms. The CSS is inspired by the Coulomb and Gauss's laws of electrostatics in physics, the governing laws of motion from the Newtonian mechanics, and the PSO is based on the swarm intelligence and utilizes the information of the best fitness historically achieved by the particles (local best) and by the best among all the particles (global best). In the new hybrid algorithm, each agent is affected by local and global best positions stored in the charged memory considering the governing laws of electrical physics. Three different types of structures are optimized as the numerical examples with the new algorithm. Comparison of the results of the hybrid algorithm with those of other meta-heuristic algorithms proves the robustness of the new algorithm.

Electret-based microgenerators under sinusoidal excitations: an analytical modeling

  • Nguyen, Cuong C.;Ranasinghe, Damith C.;Al-Sarawi, Said F.
    • Smart Structures and Systems
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    • v.21 no.3
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    • pp.335-347
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    • 2018
  • The fast-growing number of mobile and wearable applications has driven several innovations in small-scale electret-based energy harvesting due to the compatibility with standard microfabrication processes and the ability to generate electrical energy from ambient vibrations. However, the current modeling methods used to design these small scale transducers or microgenerators are applicable only for constant-speed rotations and small sinusoidal translations, while in practice, large amplitude sinusoidal vibrations can happen. Therefore, in this paper, we formulate an analytical model for electret-based microgenerators under general sinusoidal excitations. The proposed model is validated using finite element modeling combined with numerical simulation approaches presented in the literature. The new model demonstrates a good agreement in estimating both the output voltage and power of the microgenerator. This new model provides useful insights into the microgenerator operating mechanism and design trade-offs, and therefore, can be utilized in the design and performance optimization of these small structures.

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

  • Park, Junsung
    • Proceeding of EDISON Challenge
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    • 2016.03a
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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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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 s.71
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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 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.

A STUDY ON THE DESIGN, JOINTING, CHARACTERISTIC OF CONDENSER CONE OF SEALING-END FOR 154KV OF CABLE (154KV OF 종단 접속함용 CONDENSER CONE의 설계.접속.특성에 관한 연구)

  • Lee, H.S.;Oh, E.J.;Lee, K.B.
    • Proceedings of the KIEE Conference
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    • 1993.07b
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    • pp.621-623
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    • 1993
  • This paper describes the research in condenser cone of sealing-end for 154kV oil-filled underground cable. We conducted the design based on the results of electric field analysis by electrostatics theory and FEM. In case that condenser cone type EB-A was compared with bell mouth type EB-A, the results of the AC and lightening impulse voltage test showed improvment of 10 percents.

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Thermoelectric Seebeck and Peltier effects of single walled carbon nanotube quantum dot nanodevice

  • El-Demsisy, H.A.;Asham, M.D.;Louis, D.S.;Phillips, A.H.
    • Carbon letters
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    • v.21
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    • pp.8-15
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    • 2017
  • The thermoelectric Seebeck and Peltier effects of a single walled carbon nanotube (SWCNT) quantum dot nanodevice are investigated, taking into consideration a certain value of applied tensile strain and induced ac-field with frequency in the terahertz (THz) range. This device is modeled as a SWCNT quantum dot connected to metallic leads. These two metallic leads operate as a source and a drain. In this three-terminal device, the conducting substance is the gate electrode. Another metallic gate is used to govern the electrostatics and the switching of the carbon nanotube channel. The substances at the carbon nanotube quantum dot/metal contact are controlled by the back gate. Results show that both the Seebeck and Peltier coefficients have random oscillation as a function of gate voltage in the Coulomb blockade regime for all types of SWCNT quantum dots. Also, the values of both the Seebeck and Peltier coefficients are enhanced, mainly due to the induced tensile strain. Results show that the three types of SWCNT quantum dot are good thermoelectric nanodevices for energy harvesting (Seebeck effect) and good coolers for nanoelectronic devices (Peltier effect).