• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.966-969
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• 1999

Using modal transmission-line theory (MTLT), we evaluate the power coupling of optical directional coupler composed by two parallel guiding slabs. The numerical results reveal that maximum power transfer occurs at a novel wavelength λ$_{opt}$, in which the excitation ratio of supermodes at input boundary is equal to each other, and it is generally different from minimum gap λ$_{min}$.in/.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.10a
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• pp.65-74
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• 1998

In seismic design procedure of precast concrete structure, it is important to assign ductility requirement on the connection element for a favorable failure mechanism. The purpose of this paper is to propose a simplified procedure to determine the required ductility of coupling beam in coupled precast shear wall for a lateral displacement ductility at the top of a structure. This study shows that an equation for ductility of cloupling beam is introduced on the basis of several basic assumption.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.12
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• pp.1073-1077
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• 2009

The iron core, which comprises the superconducting fault current limiter (SFCL) using magnetic coupling of coils, can be operated in the saturation region, especially at the initial fault period. This operation of the iron core in the saturation region deteriorates the fault current limiting operation of the SFCL. To solve the saturation problem of the SFCL using magnetic coupling of coils, the iron core with two magnetic paths, which has an air-gap in one of them, was adopted. In this paper, the hysteresis characteristics of SFCL using magnetic coupling of coils, which were wound in the iron core with two magnetic paths, were analyzed. Through comparative analysis on the hysteresis characteristics of the iron core comprising SFCL, the hysteresis characteristics of the iron core with two magnetic paths were confirmed to be kept in the non-saturation region during the fault period and thus, the effective fault current limiting operation of the SFCL using the magnetic coupling of coils could be performed.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.2
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• pp.56-65
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• 1989

In this paper, a new model is presented which characterizs the coupling of the radiating edges between two rectangular microstrip patch antennas. This model, namely Radiating Edges-Coupling (REC) model, is derived from the equivalent circuit of the slitted parallel-plate waveguide filled with homogeneous dielectric. Applying the REC model to two coupled rectangular microstrip patch antennas, we obtain numerical S-parameter values of |$S_{11}$| and |$S_{12}$|for the various coupling separations, $S_e$=0.5, 1.0, 1.5, and 2.0mm. Theoretical results are in fairly good agreement with experimental results.

• Journal of the Korean Society for Precision Engineering
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• v.11 no.4
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• pp.99-105
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• 1994

In this study, the transverse and the torsional vibration analyses of a precision dynamic drive system with the magnetic coupling are accomplished. The force of the magnetic coupling is regarded as an equivalent transverse stiffness, which has a nonlinearity as a function of the gap and the eccentricity between a driver and a follower. Such an equivalent stiffness is calculated by and determined by the physical law and the calculated equivalent stiffness is modelled as the truss element. The form of the torque function transmitted through the magnetic coupling is a sinusoidal and such an equivalent angular stiffness, which represents the torque between a driver and a follower, is modelled as a nonlinear spring. The main spindle connected to a follower is assumed to a rigid body. And then finally we have the nonlinear partial differential equation with respect to the angular displacements. Through the procedure mentioned above, we accomplish the results of the torsional vibration analysis in a spindle system with the magnetic coupling.

• Journal of IKEEE
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• v.23 no.2
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• pp.747-750
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• 2019

Wearable devices have become practically indispensable to daily life and helped people track and manage fitness, health, and medical functions etc. As these wearable devices become smaller and more comfortable for the user, the demand for longer run time and charging ways presents new challenges for the power management engineer. Wireless power transfer (WPT) is the technology that forces the power to transmit electromagnetic field to an electrical load through an air gap without interconnecting wires. This technology is widely used for the applications from low power smart phone to high power electric railroad and main electrical grid. There are two kinds of WPT methods: Inductive coupling and magnetic resonant coupling. The model using magnetic resonant coupling method is designed for a resonant frequency of 13.45 MHz. In this study, the hardware implementations of these two coupling methods are carried out, and the efficiencies are compared.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.3
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• pp.301-310
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• 2004

In this paper, a compact dual-mode filter structure without coupling gaps is proposed. The novel design is achieved by embedding a pair of equal crossed slots and spur-lines. Without coupling gaps between feed lines and patch resonator, the new filter can provide low insertion loss. It is found that this design has wide coupling range for dual-mode operation. It means that these characteristics of the proposed filter can reduce uncertainty in fabrication. By using two PIN diodes mounted inside a pair of spur-lines, the proposed structure works as a switchable filter. Also, it has a size reduction of about 34.7 %, compared with conventional dual-mode filters.

• Journal of Magnetics
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• v.21 no.4
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• pp.516-523
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• 2016

In this paper, coupling factors are calculated based on numerical analysis in order to assess various non-uniform low-frequency magnetic field exposure situations. Two types of non-uniform magnetic field sources are considered; circular coil and parallel wires with balanced currents. For each magnetic field source, source current values are determined so that reference magnetic field magnitude can be measured at the specified point on the human model. Various exposure situations are investigated by changing parameters such as the distance between source and human model, radius of circular coil, and the gap between parallel wires. For equivalent human models, prolate spheroid model and simplified human model from IEC 62311 standard are used. The calculated coupling factor values are compared with those obtained by 2D uniform disk human model, and the dependence of coupling factor on the choice of equivalent human model is analyzed.

• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.2
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• pp.78-83
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• 2019

In this study, we analyze the structure of the transceiver coil in the inductive power transfer (IPT) system. In the IPT system, the transceiver coil design needs to have the highest magnetic coupling possible because of the relatively low magnetic coupling due to the large gap of distance without the core. The transmitting coil may be formed as a multi-layer type according to the distance between the transmitting and receiving coils if the receiving coil is configured as a multi-layer type on the inner structure of the receiving apparatus, thereby improving the magnetic coupling and system efficiency. We compare and analyze the coil magnetic coupling, and system efficiency according to the layer structure of the transmitting and receiving coils and verify the analysis by JMAG simulation. Experimental results show that the layer structure of the transceiver should be considered according to the inner space of the receiving device and the spacing distance.

• Applied Chemistry for Engineering
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• v.20 no.3
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• pp.273-278
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• 2009

A series of poly[2-(2,6-dimethylpyran-4-ylidene)malononitrile-alt-1,4-bis(dodecyloxy)-2,5-divinylbenzene] (PM-PPV), poly[2-{2,6-Bis-[2-(5-bromothiophen-2-yl)-vinyl]-pyran-4-ylidene}-malononitrile-alt-1,4-bis(dodecyloxy)-2,5-divinylbenzene] (PMT-PPV) and poly[2-[2,6-Bis-(2-{4-[(4-bromophenyl)-phenylamino]-phenyl}-vinyl)-pyran-4-ylidene]-malononitrile-alt-1,4-bis(dodecyloxy)-2,5-divinylbenzene] (PMTPA-PPV) were synthesized by the Heck coupling reaction. The band gap of PM-PPV, PMT-PPV and PMTPA-PPV were 2.18 eV, 1.90 eV and 2.07 eV, respectively. The LUMO energy levels of PM-PPV, PMT-PPV and PMTPA-PPV were 3.65 eV, 3.54 eV and 3.62 eV, respectively and the HOMO energy levels of those were 5.83 eV, 5.61 eV and 5.52 eV, respectively. The photovoltaic devices based on the polymers was fabricated. The efficiency of the solar cells based on PM-PPV, PMT-PPV and PMTPA-PPV were 0.028%, 0.031% and 0.11%, respectively and the open circuit voltage (Voc) was 0.59 V~0.69 V under AM 1.5 G and 1 sun condition ($100mA/cm^2$).