• IEIE Transactions on Smart Processing and Computing
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• v.5 no.6
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• pp.440-444
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• 2016

In this paper, an equivalent circuit model for near-field noise emission is proposed to implement a multimedia operation-monitoring system for mobile devices. The proposed model includes a magnetic field probe that captures noise emissions from multimedia components, and a transfer function for near-field noise coupling from a transmission line source to a magnetic field probe. The proposed model was empirically verified with transfer function measurements of near-field noise emissions from 10 kHz to 500 MHz. With the proposed model, a magnetic field probe was optimally designed for noise measurement on a camera module and an audio codec in a mobile device. It was demonstrated that the probe successfully captured the near-field noise emissions, depending on the operating conditions of the multimedia components, with enhanced sensitivity from a conventional reference probe.

• Journal of the Korean Physical Society
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• v.73 no.11
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• pp.1698-1702
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• 2018

We simulate the light transmission through an extremely small nanoscale aperture having a 10 nm diameter punctured in a metal film positioned at the center of a plasmonic bull's eye grating. A considerable directive emission of transmitted light with a divergence angle of 5.7 degrees was observed at $10{\mu}m$ from the nanohole opening at the frequency of surface plasmon polariton excitation, an confirmed by measuring the distance dependent transmission amplitude. Observations of the electric field in cross-sectional, near-field, and far-field views near-field enhancement associated with the surface plasmon excitation, and the interference of the electric field light through the nanohole in the near-field region is responsible for such a considerable directive emission.

• Journal of the Korean Ceramic Society
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• v.39 no.1
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• pp.92-98
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• 2002

To investigate the electrode structural effect on the ferroelectric electron emission, the electric field distribution in a 2-dimensional structure was calculated as a function of upper electrode diameter, and the switching charge density and emission charge were measured simultaneously. The simulation of the electric field distribution showed that an asymmetric electrode structure could cause a stray field on the bare surface of the ferroelectric cathode near the edge of upper electrode. The distance of stray field from the electrode edge increased with increasing ferroelectric thickness, but it did not depend on the upper electrode diameter. The switching charge density increased more on the cathode with smaller upper electrode diameter. This was attributed to the stray field on the bare ferroelectric surface near the electrode edge, because the stray field for the asymmetric ferroelectric cathode enhanced polarization switching near the electrode edge. From the switching charge density, the distance of stray field from the electrode edge was calculated as about 11-14${\mu}{\textrm}{m}$. The threshold voltage of electron emission was 61-68 kV/cm, which was almost 3 times lager than the coercive voltage. The threshold voltage was not determined just by coercive voltage, but by strength and distance of the stray-field, which largely depended on the geometrical structure of ferroelectric cathode.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.1
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• pp.59-63
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• 2000

For the Mo-tip field emitter array, the method by which the geometrical structure of the gate insulator wall could be modified in order to improve field emission properties(turn-on voltage and gate leakage current). The device having a gate insulator of complex shape, which means the combined geometrical structure with round shape made by wet etching and vertical shape made by dry etching processes, was fabricated and the field emission properties of the three kinds of devices were compared. As a result, the electric field applied to tip apex could be increased and gate leakage current could be decreased by employing the gate insulator having geometrical wall structure of mixed shape. Finally, the obtained empirical results were analyzed by simulation of electric field distribution at/near the tip apex and gate insulator using SNU-FEAT simulator.

• Korean Journal of Materials Research
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• v.9 no.10
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• pp.1032-1036
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• 1999

The electron emission and degradation of the ferroelectric Pb($\textrm{Zr}_{0.5}\textrm{Ti}_{0.5}$)$\textrm{O}_3$ ceramics by the pulse electric field have been investigated as a function of the upper electrode diameter. Polarization increased with the decrease of the upper electrode diameter due to the increase of the volume fraction participated in the polarization reversal near the electrode edge. Simulation using ANSYS 5.3 for the electric field distribution showed that the electric field increased near the upper electrode edge of the asymmetric electrode structure. The ferroelectric volume near the upper electrode edge which contributed to the increase of the polarization and the emission charge per electrode diameter were independent on the upper electrode diameter. Polarization and dielectric constant were decreased due to the erosion of the upper electrode with repeating the emission cycles, but they were recovered by the electrode regeneration. The degradation of the ferroelectric surface resulted in the increase of the coercive field and dielectric loss.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.568-570
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• 2004

A shielding effectiveness of mesh screen filter of plasma display panel (PDP) has been calculated in this paper. Since the screen filter is located near the radiation source, the near field wave impedance of the radiation source, i.e., the PDP electrodes, has been considered to calculate the shielding effectiveness. The near field shielding effectiveness of screen filter at 30${\sim}$300 MHz has been estimated to be more than 65${\sim}$80 dB. The measured shielding effectiveness of screen filter is 10${\sim}$50 dB at 30${\sim}$300 MHz[1]. The resulting discrepancy indicates that there are other EMI emission sources such as emission from PCB and cable besides the PDP electrodes.

• Proceedings of the Optical Society of Korea Conference
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• 2001.08a
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• pp.10-11
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• 2001

• Journal of the Optical Society of Korea
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• v.6 no.1
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• pp.1-4
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• 2002

We studied experimentally the angular spectrum of the light emitted from dye Molecules near a plane boundary. It is confirmed that the molecules near the boundary can emit light into the evanescent wave mode, and the light emission with the angle greater than the critical angle is detected with good accuracy. The angular spectrum of the spontaneous radiation is measured, and the spectrum shows contributions from the molecules both near and far away from the boundary. The polarization dependence and the pumping angle dependence are also measured. The experimental results are in good agreement with quantum theory.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.859-862
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• 2003

Well-aligned multiwall carbon nanotubes (MWCNTs) were prepared at low temperature of 400 $^{\circ}C$ by utilizing a radio frequency plasma-enhanced chemical vapor deposition (rf-PECVD) system. The MWCNTs were treated by an external rf plasma source and an ultra-violet laser in order to modify structural defect of carbon nanotube and to ablate possible contamination on carbon nanotube surface. Structural properties of carbon nanotubes were investigated by using a scanning electron microscopy (SEM), Raman spectroscopy, Fourier transformer Infrared spectroscopy (FTIR) and transmission electron microscope (TEM). In addition, the emission properties of the MWNTs were measured for the application of field emission display (FED) in near future. Various post treatments were found to improve the field emission property of carbon nanotubes.

• Journal of the Korean Society of Combustion
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• v.17 no.4
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• pp.60-65
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• 2012

The MILD combustion and pollutant emission characteristics were investigated computationally. The temperature of supplying air-stream and mixing rate (${\Omega}$) of exhaust gas in the air-stream were adjusted to investigate the effects of those parameters on the MILD combustion in jet flow field. The emission indices for NO (EINO) and CO (EICO) were introduced to quantify the amount of those species emitted from the combustion. The high-temperature region disappeared gradually as the mixing rate increased for fixed air-stream temperature. The EINO increased as the air-stream temperature became higher for fixed mixing rate, and the EINO decreased dramatically with increasing the mixing rate for each air-stream temperature condition. The EICO also decreased with increasing the mixing rate and it was nearly independent of air-stream temperature except for near ${\Omega}$ = 0.7. It was found that the CO supplied in the air-stream can be destroyed in the MILD combustion over the certain mixing rate.