• Proceedings of the Optical Society of Korea Conference
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• 1990.02a
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• pp.64-68
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• 1990

Boundary element method using linear basis function is applied to obtain fields scattered from a 3-D dielectric sphere. Electric field integral equation is used on the surfaces of the dielectric material where its surface is discretized into trilateral cells. For plane wave incidence, scattered fields by a dielectric sphere is calculated and compared with its analytic solution. The total electric fields are calculated on the great circle of the sphere boundary as well as the outside of the sphere in the plane of the wave vector and the polarization vector of the incident electric field.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.391-393
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• 1997

Two kinds of the calculation technique are Investigated with 3D triangular SCM for the arrangement of the dielectric sphere with different resistivity under a uniform electric field. The calculation error of Method I is small outside the sphere, but considerably high Inside. On the other hand, the accuracy is much Improved even Inside the solid dielectric by Method II, which uses double layers of triangular charges on the dielectric boundary.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.730-732
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• 1992

In this study, piezoceramics/polymer composites with 3-3 connectivity were made by BURPS(Burnout Plastic Sphere) technique with PZT ceramics and PMMA sphere(50 - 80${\mu}m$). And the dielectric and piezoelectric properties dependent on the PZT vol.% were investigated. The dielectric constant($K_{33}$) of 3-3 composites is increased almost linearly with increasing the PZT vol.%, while piezoelectric coefficient($d_{33}$) is slightly increased.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.3
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• pp.280-285
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• 2023

A breakdown voltage and breakdown electric field of the transformer insulating oil of liquid dielectric were studied in uniform electric field and non-uniform electric field and the transformer insulating oil was observed by the process reached breakdown. Insulation performance evaluation of the liquid dielectric was evaluated at the electrode spacing of 2.5 mm under the conditions of domestic and international standards (KS C IEC 60156), so a comparative review was conducted at the electrode spacing of 2.5 mm. When the electrode spacing is 2.5 mm, the average breakdown voltage is 38.5 kV for sphere-sphere electrodes, 26.6 kV for plate-plate electrodes, 22.9 kV for needle-needle electrodes, and 24.3 kV for sphere-needle electrodes. 23.7 kV for the sphere-plate electrode, and 20.7 kV for the needle-plate electrode. From these results, it can be seen that the average value of the breakdown voltage at the electrode spacing of 2.5 mm, in ascending order, is sphere-sphere, plate-plate, sphere-needle, sphere-plate, needle-needle and needle-plate. It was found that the breakdown voltage of the unequal field was lower than that of the equal field.

• Journal of electromagnetic engineering and science
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• v.14 no.1
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• pp.9-14
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• 2014

This paper discusses the resonant characteristics, such as the resonant frequencies and Q factors, as well as tuning methods of the resonant frequency of the triple-mode dielectric resonators, for their possible application to compact bandpass filters for mobile communication systems. The resonators include spheres and cylindrical rods that can be applied to compact bandpass filters. These high Q ceramic resonators can replace the conventional coaxial type resonators, which are large sized and also have relatively low Q values. Both simulated and measured results show that the Q values of the sphere and rod reach 27,000 and 24,000, respectively. Decoupling of degenerate modes is also briefly discussed.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.7
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• pp.26-31
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• 1993

We have analyzed shielding characteristics of the spherical multilayered dielectric, with the assumption that the inner part of the model is filled with the perfect conductor whose radius is varied from 0.2.lambda. to 1.0.lambda. and the outer part of the conducting sphere is covered by a lossy multilayered dielectric. Variation of shielding effects have been examined as the function of parameter of the dielectric layer and the radius of the conducting sphere.

• Journal of Powder Materials
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• v.12 no.4 s.51
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• pp.291-295
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• 2005

CdSe hollow sphere with average size of about 30-50 nm was synthesized from the mixed solution of cadmium chloride $(CdCl_2)$, sodium selenosulfate $(Na_2SeSO_3)$ and ethylenediamine(EDA, $H_2NCH_2CH_2NH_2$) at room temperature. The molar ratio of EDA to $Cd^{2+}$ showed the most significant effect on the morphology of CdSe hollow sphere. This paper will present and discuss the possible formation mechanism of CdSe hollow sphere based on the observation of morphological changes.

• Progress in Superconductivity and Cryogenics
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• v.17 no.3
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• pp.33-36
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• 2015

A liquid nitrogen ($LN_2$) is usually used to be a coolant and insulant for a HTS coil system. HTS wires for a superconducting apparatus may be surrounded by gaseous nitrogen ($GN_2$) due to film boiling generated by a quench or voids occurred by electrical breakdown. The increased maximum electric field intensity at $GN_2$ may result in the degradation of dielectric strength of a HTS coil system. In this paper, a study on the dielectric characteristics of a composite insulation system composed of $LN_2$ and $GN_2$ is performed. A sphere-to-plane electrode system made with stainless steel is used to perform the experiments under AC and lightning impulse voltage condition. A sphere electrode is surrounded by $GN_2$ and a plane electrode is immersed into $LN_2$ to conduct dielectric experiments with a composite insulation system. The dielectric experiments are performed according to the level of $LN_2$ from the plane electrode to a sphere electrode. It is found that the dielectric characteristics of a composite insulation system are dependent on the level of $LN_2$ and the field utilization factor of an electrode system.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.263-266
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• 2007

In this paper approves (AC and DC) high voltage by experimental GIS(Gas Insulated Switchgear) chamber and (AC and DC) power source to study breakdown characteristics by pressure(P) change and change of electrode distance(d) at (AC and DC) high voltage of Imitation I-Air, $N_2$ : $O_2$ = 79(%) : 21[%]) to alternate $SF_6$ and achieved research. Gave P change of I-Air to study I-Air's Dielectric Strength using uniform and non-uniform fields(sphere-sphere and Needle-Plane electrode) and studied relations dielectric strength($V_D$) by each P different d.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.4
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• pp.515-523
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• 2012

In this paper, the resonance characteristics and radiation characteristics of a spherical patch on a dielectric sphere are analyzed. Resonance characteristics can be obtained from the resonant frequency and the quality factor. Radiation characteristics can be also analyzed from the E-field in the far region. In order to calculate these parameters, spectral domain analysis method is applied. Algebraic equation can be obtained in spectral domain through Vector Legendre transform pair and Galerkin's method. So, efficient calculation is possible numerically. It is investigated that radius, curvature of a spherical patch, and dielectric constant of a dielectric sphere have an effect on characteristics of a spherical patch.