• Title/Summary/Keyword: electrode geometry

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Determination of energetically preferable Au-S contact atomic structure in stretched single-molecule junctions

  • Ko, Kwan Ho
    • Proceeding of EDISON Challenge
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    • 2014.03a
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    • pp.409-411
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    • 2014
  • Based on the first-principles computations, the nature of the microscopic geometry of the molecule-electrode contacts was addressed. The single-molecule junction was prepared by connecting hexanediothiolate (HDT) to Au(111) electrodes via one, two, and three Au adatoms having coordination number of one (CN1), two (CN2), and, three (CN3), respectively. The contact atomic structure and energy of the stretched Au-HDT-Au junction was observed. The analysis revealed that the contact geometry with lowest coordination number (CN1) is energetically more stable than CN2 and CN3.

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A Model of a Simplified Mammography Geometry for Breast Cancer Imaging with EIT (전기임피던스 단층촬영법을 위한 단순화된 매모그래피 구조의 모델)

  • Choi, Myoung-Hwan
    • Journal of Industrial Technology
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    • v.26 no.B
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    • pp.221-226
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    • 2006
  • Electrical impedance tomography (EIT) is a technique for determining the electrical conductivity and permittivity distribution within the interior of a body from measurements made on its surface. One recent application area of the EIT is the detection of breast cancer by imaging the conductivity and permittivity distribution inside the breast. The present "gold standard" for breast cancer detection is X-ray mammography, and it is desirable that EIT and X-ray mammography use the same geometry. This paper presents a forward model of a simplified mammography geometry for EIT imaging. The mammography geometry is modeled as a rectangular box with electrode arrays on the top and bottom planes. A forward model for the electrical impedance imaging problem is derived for a homogeneous conductivity distribution and Validated by experiment using a phantom tank.

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Iron(II) Tris(3-bromo-1,10-phenanthroline) Complex: Synthesis, Crystal Structure and Electropolymerization

  • Lee, Kyeong-Jong;Yoon, Il;Lee, Shim-Sung;Lee, Bu-Yong
    • Bulletin of the Korean Chemical Society
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    • v.23 no.3
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    • pp.399-403
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    • 2002
  • The complex of iron(II) tris(3-Br-phen) (3-Br-phen; 3-bromo-1,10-phenanthroline) was prepared as a precursor of electropolymerization and the crystal structure of [Fe(3-Br-phen)3]($PF_6$)2${\cdot}$CH3CN with a distorted octahedral geometry has been investigated. The reductive electropolymerization of $>[Fe(3-Br-phen)3]^{2+}$ complex onto the surface of a glassy carbon electrode and indium tin oxide (ITO) optically transparent electrode were performed in acetonitrile at room temperature. Thin film of poly-$>[Fe(3-Br-phen)3]^{2+}$ formed was adherent, electroactive and stably deposited on a glassy carbon disk electrode. The thin metallopolymeric film formed was also confirmed by absorption spectroscopy.

광폭 전기집진기의 집전특성에 관한 연구 - I. 집진판 간격과 방전극의 영향 -

  • 김용진;하병길;정상현;홍원석;여석준;유주식
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.13 no.10
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    • pp.939-946
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    • 2001
  • This study investigates the electrical and collection characteristics of a wide plate spacing electrostatic precipitator (ESP), using a pilot-scale one. Electrical operating characteristics and collection efficiency were measured for various shapes of discharge electrodes. The collection plate spacing ranged from 300 to 550 mm. Results of electrical characteristic and collection efficiency tests as a function of collection plate spacing, discharge electrode type, applied voltage, and particle diameter were obtained. Increasing the collection plate pitch and altering the corona electrode geometry was found to increase the collection efficiencies without increasing input power requirement. The best efficiency is achieved for the discharge electrode of twisted pin type.

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A Dual In-Plane Electrode Structure for Better Brightness in a Helix-Deformed FLCD

  • You, Doo-Hwan;Lee, Sin-Doo;Lee, Ju-Hyun;Na, Do-Jun
    • Journal of Information Display
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    • v.2 no.1
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    • pp.1-4
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    • 2001
  • We propose a dual in-plane parallel electrode structure of a vertical configuration of a helix-deformed ferroelectric liquid crystal (HDFLC) mode for better brightness than a single in-plain electrode case. This structure provides high brightness in addition to the analog gray scale capability, fast response, and wide-viewing characteristics. In contrast to a conventional HDFLC in a planar geometry, smectic layers arrange themselves parallel to the substrates and thus extremely uniform alignment of molecules in a large area is naturally achieved in our new configuration.

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Survival of the Insulator under the electrical stress condition at cryogenic temperature

  • Baek, Seung-Myeong;Kim, Sang-Hyun
    • Progress in Superconductivity and Cryogenics
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    • v.15 no.4
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    • pp.10-14
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    • 2013
  • We have clearly investigated with respect to the survival of the insulator at cryogenic temperature under the electrical stress. The breakdown and voltage-time characteristics of turn-to-turn models for point contact geometry and surface contact geometry using copper multi wrapped with polyimide film for an HTS transformer were investigated under AC and impulse voltage at 77 K. Polyimide film (Kapton) 0.025 mm thick is used for multi wrapping of the electrode. As expected, the breakdown voltages for the surface contact geometry are lower than that of the point contact geometry, because the contact area of the surface contact geometry is lager than that of the point contact geometry. The time to breakdown t50 decreases as the applied voltage is increased, and the lifetime indices increase slightly as the number of layers is increased. The electric field amplitude at the position where breakdown occurs is about 80 % of the maximum electric field value. The relationship between survival probability and the electrical stress at cryogenic temperature was evident.

Characterization of a LSCF/GDC Cathode Composite in Solid Oxide Fuel Cells Using Impedance Spectroscopy

  • Hwang, Jin-Ha;Lee, Byung-Kook
    • Journal of the Korean Ceramic Society
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    • v.42 no.12 s.283
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    • pp.793-799
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    • 2005
  • A composite cathode of LSCF$(La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_3)\;and\;GDC\; (Gd_2O_3-doped\;CeO_2:Ce_{0.9}Gd_{0.1}O_{1.95_})$ was characterized in terms of an electrode response, using a point contact in an Yttria-Stabilized Zirconia (YSZ) electrolyte incorporated into AC two-point impedance spectroscopy. The point-contacted configuration amplifies the responses occurring near the YSZ/cathode interface through the aligned point contact on the planar LSCF/GDC electrode. The point contact interface increases the bulk resistance allowing the estimation of the point contact geometry and resolving the electrode-related responses. The resultant impedance spectra are analyzed through an equivalent circuit model constructed by resistors and constant phase elements. The bulk responses can be resolved from the electrode-related portions in terms of spreading resistance. The electrode-related polarizations are measured in terms of temperature and oxygen partial pressure. The modified impedance spectroscopy is discussed in terms of methodology and analytical aspects, toward resolving the electrode-polarization issues in solid oxide fuel cells.

Influence of electrode geometry on electrical resistivity survey: Numerical study (전극의 기하학적 형상이 전기비저항 탐사에 미치는 영향: 수치 해석 연구)

  • Tae-Young Kim;Seung-Hun Lee;Hee-Hwan Ryu;Song-Hun Chong
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.25 no.2
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    • pp.101-120
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    • 2023
  • Electrical resistivity survey have been widely conducted at diverse scales, from a few centimeters for laboratory tests to kilometers for field tests. It measures electrical resistance through relationship of electric potential difference and current between two electrodes penetrated on the surface of medium, and eventually quantifies electrical resistivity known as inherent properties of the medium. In field or full-scale test, it assumes the electrodes as equivalent half-sphere electrodes that have a same surface area with different electrodes for ease of calculation because the contact area between electrode and medium is small and sufficient distance between two electrodes. However, small-scale laboratory test is significantly affected by the electrode geometries (penetrated depth, height, radius of electrode and distance between electrodes), which change the equipotential surface and electric current flow. Indeed, the electrode geometries may eventually cause a difference of electrical resistivity value. This study reviews the theoretical electrical resistance derived with various electrode geometries (half-sphere, cylinder, cylindrical with half-spherical tip, cylindrical with conical tip) and verifies the developed numerical module by comparing results with the theoretical electrical resistance. The distributions of electrical resistance around electrodes and among electrodes are analyzed. In addition, it is discussed how the electrical characteristic of cylindrical electrode with conical tip widely used in field test has effect on the electric current flow.