• Journal of the Korean Mathematical Society
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• v.35 no.1
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• pp.225-234
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• 1998

We compute genus distributions for bouquets of dipoles by using the method concerning the cycle structure of permutations in the symmetric group. From this, we can deduce that every bouquet of dipoles is upper embeddable. We find a foumula for computing the embedding polynomials for bouquets of dipoles.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.19 no.5
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• pp.237-241
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• 2009

Dislocation dipoles were formed in the early stage of deformation of Y-CSZ single crystal at high temperatures. And the dipoles were pinched off to break into dipoles loops by dislocation climb. Dislocation loop annealing was peformed in Y-CSZ single crystal to evaluate the diffusivity of cation which was the rate-controlling ion.

• Journal of electromagnetic engineering and science
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• v.13 no.4
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• pp.224-232
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• 2013

This paper describes composite cavity-backed crossed scythe-shaped dipoles with wide-beam circularly polarized (CP) radiation for use in Global Navigation Satellite Systems. Each branch of the dipole arm contains a meander line, with the end shaped like a scythe to achieve a significant reduction in the size of the radiator. For dual-band operation, each dipole arm is divided into two branches of different lengths. The dipoles are crossed through a $90^{\circ}$ phase delay line of a vacant-quarter printed ring to achieve CP radiation. The crossed dipoles are incorporated with a cavity-backed reflector to make the CP radiation unidirectional and to improve the CP radiation beamwidth. The proposed antennas have broad impedance matching and 3-dB axial ratio bandwidths, as well as right-hand CP radiation with a wide-beamwidth and high front-to-back ratio.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.177-180
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• 2001

A decoupled, wide-band, perfectly magnetically conductor(PMC)-backed air waveguide antenna is designed and constructed for the use of the continuous electromagnetic wave ground penetrating radar in the frequency range from 200MHz to 600MHz. Two planar dipoles are located inside air slab covered by PMC on the top side and separated by an air gap from the bottom ground interface. The coupling between the transmitting and the receiving dipoles is calculated by less than -60dB over the frequency from 200MHz to 600MHz.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1617-1619
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• 2000

In this study the nonlinear dielectric properties of amorphous copolymers were analyzed by the related nonlinear dielectric theory. The theory is related to the cooperated dipoles and the number of the dipoles. The relation between the polarization coefficient $R_p$ and the nonlinear coefficient $R_s$ was deduced under the assumption of isotropic media.

• Kyungpook Mathematical Journal
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• v.33 no.1
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• pp.115-125
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• 1993

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.3
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• pp.584-590
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• 1994

A theoretical model has been developed to analyze the jet-edge interaction and the sound radiation. The edge responding to the sinuous impinging jet is regarded as an array of dipoles and their strength is determined by the boundary condition on the edge surface. The surface pressure distribution and the edgeforce are estimated using these dipoles. Then the pressure amplitude and directivity of the sound field is obtained by summing the radiating sounds from the dipole sources. It is found that the effective source is located a little distance downstream from the edge tip. And the directivity of the sound radiation is cardioid pattern near the edge but dipole pattern far from the edge. The theoretical model is confirmed by comparing the theoretical prediction of the edgeforce and sound pressure level with available experimental data.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.6
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• pp.491-496
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• 2010

The relaxation behavior of aligned electric dipoles in a mixed polymer of P2ANS with P(VDF-TrFE) is studied with optical second harmonic generation (SHG). In this work, a macroscopic noncentrosymmetry of the spin coated film was achieved by an electrical poling. The relaxation of induced polar order of nonlinear optic(NLO) chromophores after poling leads to an insufficient long-term stability of NLO properties. In this work, we develop a new technique to suppress such kind of dipole relaxation in a poled polymer. We found that the poled dipoles in a NLO polymer were effectively immobilized by the internal electric field created by a thermally annealed ferroelectric polymer. The long-term stability in a mixed system of NLO polymer/ferroelectric polymer was successively accomplished by a series of thermal treatments applied to the mixed polymer system at a temperature of $140^{\circ}C$ for at least 1hour after poling.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.60 no.2
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• pp.53-55
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• 2011

The printed wide band monopole antenna having characteristics of dipole by modified coplanar wave guide(CPW) ground plane is presented. We are called a slot-arm printed monopole antenna and investigated the effect of the surface currents of the radiator on ground plane. The proposed antenna is treated as two asymmetric dipoles with the included angle of $90^{\circ}$ degrees which lie along Z-direction symmetrically. It is observed that the effect of the surface currents on the radiation patterns is similar to that of the corresponding dipole. The length and width of the ground plane correspond the radius and length of the dipole respectively. This approach is also valid to general printed monopole antennas. The simulation impedance bandwidth of the proposed antenna the range of 2.4 to 4.6 [GHz] for a voltage stand wave ratio (VSWR)${\leq}$2 and got pick gain of 6 [dBi]. So the proposed antenna is satisfied the requirement of the industry science medical (ISM) band operation.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.7
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• pp.279-286
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• 2002

Linear and nonlinear complex permittivities were measured for copolymers of vinylidene cyanide(VDCN) with vinyl acetate(VAc), vinyl propionate(VPr), vinyl bezoate(VBz), styrene(St) and methyl methacrylate(MMA). Experimental results are well fitted by the function (equation omitted) except at low frequency where dc conduction dominates. The analysis of dielectric relaxation mechanism by combined knowledge about linear and nonlinear dielectric permittivities and dipoles give us informations about electrical and thermal motions in these copolymers. According to the analysis it could be found that the variation for temperature of the dielectric relaxation strength in these copolymers is related to the interaction between dipoles and the nonlinear dielectric effect factor R$_{s}$ is proportional to square of the dipolar correlation factor R$_{p}$././.