• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.3
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• pp.71-76
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• 2023

In this paper, TE(transverse electric) scattering problems by a resistive strip grating between a grounded double dielectric layer are analyzed by applying the FGMM(fourier galerkin moment method) known as a numerical method of electromagnetic fileld. The boundary conditions are applied to obtain the unknown field coefficients, the scattered electromagnetic fields are expanded in a series of Floquet mode functions, and the resistive boundary condition is applied to analysis of the resistive strip. Overall, as the resistivity decreased, the magnitude of the current density induced in the resistive strip increased, and the reflected power also increased. In case of uniform resistivity, the reflected power decreased as the relative permittivity of the dielectric layers increased or the thickness of the dielectric layer increased. The numerical results for the presented structure in this paper are shown in good agreement compared to those of the existing papers.

• The Journal of the Convergence on Culture Technology
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• v.9 no.3
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• pp.619-624
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• 2023

In this paper, TE(transverse electric) scattering problems by a resistive strip grating between a double dielectric layer are analyzed by using the FGMM(fourier galerkin moment method) known as a numerical method of electromagnetic fileld. The boundary conditions are applied to obtain the unknown field coefficients, the scattered electromagnetic fields are expanded in a series of Floquet mode functions, and the resistive boundary condition is applied to analysis of the resistive strip. In order to deal with the problem of the double dielectric layer, numerical calculation was performed only when the thickness and relative permittivity of the dielectric layers had the same value. Overall, as the resistivity of the uniform resistivity increased, the current density induced in the resistive strip decreased, the reflected power decreased, and the transmitted power relatively increased. The numerical results of the structure proposed in this paper are shown in good agreement compared to the results of PMM, a numerical analysis method of the existing paper.

• Journal of Sensor Science and Technology
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• v.14 no.1
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• pp.56-61
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• 2005

This paper present characteristics of chromium oxide thin-film as piezoresistive sensors, which were deposited on Si substrates by DC reactive magnetron sputtering in an argon-Oxide atmosphere for high temperature applications. The chemical composition, physical and electrical properties and thermal stability ranges of the $CrO_{x}$ sensing elements have studied. $CrO_{x}$ thin films with a linear gauge factor(GF${\fallingdotseq}$15), high electrical resistivity (${\rho}$ = $340{\mu}{\Omega}cm$) and TCR<-55 ppm/$^{\circ}C$ have been obtained. These $CrO_{x}$ thin films may allow high temperature pressure sensor miniaturization to be achieved.

• Economic and Environmental Geology
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• v.30 no.5
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• pp.451-458
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• 1997

The horizontal magnetic dipole as well as electrical dipole was adopted as a source to compute one-dimensional electromagnetic field behavior in controlled source magnetotellurics. he Cagniard impedances due to horizontal magnetic dipole source, especially phases, showed better frequency characteristics than those due to electric one. The magnetic dipole is inferior to the electric dipole in the point of relatively weak transmitting power at low frequency. But considering high resistivity charateristics of Korean geology, the magnetic dipole source is recommended for the survey up to depth of 500 m. A vector CSMT was introduced to get more reliable data in the area of two- or three-dimensional structures. A software and interpretation technique using polarization ellipses were developed. The technique was tested by synthetic data, which provided theoretical basis of the methodology. Although CSMT has inevitable limitation of investigation depth due to practically possible source-receiver separation, we proposed to use the technique developed in this paper where MT is not available, for example, in extremely noisy area or for shallow target.

• 한국초전도학회:학술대회논문집
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• v.9
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• pp.271-274
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• 1999

We are investigating epitaxially grown YBa$_2Cu_3O_x$(123) on MgO single crystal by partial melting process for high power application. After fabricating of BaCuO$_2$(011), Y$_2BaCuO_5$(211) powder, we made YBa$_2Cu_3O_x$(123) Paste with just mixing of (211), (011) and CuO(001) powders. Screen printing method was used to coat YBa$_2Cu_3O_x$(123) paste on MgO single crystal. To reduce the reaction in low temperature, rapid heating was conducted at partial melting temperature. The film was analysed with the difference of cooling-rate, thickness, reaction temperature by XRD, SEM, in-plane alignment, out-of-plane alignment, temperature-resistivity characteristics.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.10
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• pp.1079-1084
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• 2004

This work describes the effect of electrode binder on the characteristics of electric double layer capacitor. Among carboxymethylcellulose (CMC), Polyvinylpyrrolidone (PVP), Polyvinyl Alcohol (PVA), and Polyvinylidene Fluoride (PVDF), the unit cell using CMC showed good rate capability at current densities between 2.5 mA/$\textrm{cm}^2$～100 mA/$\textrm{cm}^2$. However, CMC as a binder is incongruent, because the electrode bound with CMC is rigid and easy to crack during a press and winding process for fabrication of capacitor. The unit cell capacitor using the electrode bound with binary binder composed of CMC and Polytetrafluoroethylene (PTFE), especially in composition CMC : PTFE =60 : 40 wt.%, has exhibited the better mechanical properties than those of the unit cell with CMC. On the other hand, the mechanical properties of CMC+PTFE electrode, coated on underlayer composed of CMC and carbon black, were much improved.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.9
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• pp.1374-1379
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• 2012

Urban rail transit tends to global grounding system in order to control ground potential rise and potential differences between electric equipments. In addition, global grounding system can discharge the large capacity surge current to the ground safely. Since some railway electric equipments are installed all section of line, the global grounding system connected with the connecting grounding wire is more effectively. However, if the fault occurred in the connecting grounding wire area, some dangerous voltage is generated. So, the installation of additional grounding rod will be required. In this study, the global grounding system is simulated using CDEGS program to analyze the divergence spacing of additional ground rod depending on dangerous electric potential characteristics. Grounding net of the each station is modelled in depending on the size of the platform, and the spacing of the connecting grounding rod are compared 50m, 100m, 250m and 400m. Simulation results considering of earth resistivity and underground condition of the connecting grounding wire, spacing of the connecting grounding rod is that less than 250m to spacing of the ground rod was appropriately confirmed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.545-545
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• 2007

Recently, innovative process has been investigated in order to replace the conventional high-cost micro patterning processes on the electronic products. To produce desirable profit margins from this low cost products, printed circuit board(PCB), will require dramatic changes in the current manufacturing philosophies and processes. Innovative process using metal nano particles replaces the current industry standard of subtractive etched of copper as a highly efficient way to produce robust circuitry on low cost substrates. An advantage of using metal nano particles process in patterned conductive line manufacturing is that the process is additive. Material is only deposited in desired locations, thereby reducing the amount of chemical and material waste. Simply, it just draws on the substrate as glass epoxy or polyimide with metal nano particles. Particles, when their size becomes nano-meter scale, show some specific characteristics such as enhanced reactivity of surface atoms, decrease in melting point, high electric conductivity compared with the bulk. Melting temperature of metal gets low, the metal nano particles could be formated onto polymer substrates and sintered under $300^{\circ}C$, which would be applied in PCB. It can be getting the metal line of excellent electric conductivity.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.541-542
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• 2006

This work describes the effect of the number of roll pressing and the composition of carbon black on the electric and mechanical properties of carbon-PTFE electrode, in which composition is MSP 20 : carbon black : PTFE = 95-X : X : 5 wt.%. It was found that the best electric and mechanical properties were obtained for sheet electrode roll pressed about 15 times and for sheet electrode, in which composition is MSP 20 : carbon black : PTFE = 80 : 15 : 5 wt.%. These behaviors could be explained by the network structure of PTFE fibrils and conducting paths linked with carbon blacks, respectively. On the other hand, cell capacitor using the sheet electrode with 15 wt.% of carbon black attached on aluminum current collector with the electric conductive adhesive, in composition is carbon black : CMC = 70 : 30 wt.%, has exhibited the best rate capability between $0.5mA/cm^2{\sim}100mA/cm^2$ current density and the lowest ESR.

• Polymer(Korea)
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• v.32 no.4
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• pp.353-358
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• 2008

Maleated ethylene-propylene-diene terpolymer (MEPDM) was prepared from solution polymerization of EPDM and maleic anhydride. MEPDM-grafted-poly (dimethylsiloxane) (PDMS) copolymer (MEPDM-g-PDMS) was prepared from copolymerization of MEPDM with $\alpha$,$\omega$-hydroxyl group terminated PDMS. The MEPDM-g-PDMS was compounded with HDPE and 4-ethoxybenzoic acid modified MWCNT at $180^{\circ}C$ and positive temperature coefficient (PCT) behavior of the MWCNT composite was investigated. Surface modification of MWCNT enabled it to be more uniformly dispersed in polymer matrix and decreased aggregation of particles. Electrical resistivity of the composite was abruptly increased at melting temperature and PTC intensity of 2.3 was obtained at 15% loading of surface modified CNT.