• Journal of IKEEE
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• v.14 no.3
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• pp.199-204
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• 2010

In this paper, we proposed trench field ring for breakdown voltage of power devices. The proposed trench field ring was improved 10% efficiency comparing with conventional field ring. we analyzed five parameters of trench field ring for design of trench field ring and carried out 2-D devices simulation and process simulations. That is, we analyzed number of field ring, juction depth, distance of field rings, trench width, doping profield. The proposed trench field ring was better to more 1000V.

• Journal of Korean Vacuum Science & Technology
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• v.3 no.1
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• pp.10-15
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• 1999

Using micro-wells on the Mo substrate, we could obtain various tubular-volcano-types of free-standing diamond field emitters by depositing a diamond film detaching the film and turning the film upside down. The field emission characteristics of these structures were investigated as a function of size, shape and the number density of the tubular-volcano-type diamond field emitters. The field emission characteristics, especially the current density, were greatly enhanced with increasing the number density of the tubular-volcano-type diamond field emitters on the Mo substrate. Based on these results, we suggest that the reduction of the well size can give better field emission characteristics by the increase in the number density of the tubular-volcano-type diamond field emitters. Finally, we suggest the feasibility of fabricating a large-area field emission display using our patterned tubular-volcano-type free-standing diamond field emitters.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.1
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• pp.1-5
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• 2010

In this paper, we proposed trench field ring for breakdown voltage of power devices. The proposed trench field ring was improved 10% efficiency comparing with conventional field ring. we analyzed five parameters of trench field ring for design of trench field ring and carried out 2-D devices simulation and process simulations. That is, we analyzed number of field ring, juction depth, distance of field rings, trench width, doping profield. The proposed trench field ring was better to more 1000 V.

• Journal of the Korean Geophysical Society
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• v.7 no.1
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• pp.11-21
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• 2004

The variation of geomagnetic field and absolute magnetic field at the geomagnetic observatory of King Sejong Station has been measured with 3-component ring core fluxgate magnetometer, proton magnetometer and D-I magnetometer. With data obtained from King Sejong Station during 2003, thediurnal and annual variations of geomagnetic field were researched and compared with those at other observatories. The deviation of daily variation of magnetic field in antarctica decreased gradually during winter season due to sun effect. The rates of componental annual variation of magnetic field at King Sejong Station were calculated using the least-square method under the assumption that the annual variation of magnetic field is linear. The rates are -55.93 nT/year in horizontal intensity, -0.87 min./year in declination, 58.30 nT/year in vertical intensity, and -69.85 nT/year in total intensity of magnetic field. A remarkable variation was caused by the magnetic storms occurred on 29~30 October, which were so powerful that the variation was observed in mid latitudes as well as high latitudes. The values of variation are generally 1500 2000 nT in Antarctica including King Sejong Station, 350 500 nT in East Asia. The measurement of absolute magnetic field shows that ring core fluxgate magnetometer has relatively large error range under cold temperature.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.5
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• pp.852-857
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• 2006

This paper presents a precision method to calculate the electric field density of mountain area using digital terrain elevation data(DTED). Generally we calculate the electric field density of a point adding a direct field density and horizontal reflection field density between two points. In this paper, we consider a vertical reflection field density from vertical surface near the wave propagation line between transmitter and receiver. The vertical reflection electric field have different propagation path and polarization from a horizontal reflection field. And the total electric field density adding horizontal field density and vertical reflection value is more accurate than a direct path electrical field density or direct field density adding a horizontal reflection field density.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.2
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• pp.49.2-49.2
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• 2010

In order to understand the configuration of magnetic field producing a solar penumbral microjet that was recently discovered by Hinode, we performed a magnetohydrodynamic simulation reproducing a dynamic process of how that configuration is formed in a modeled solar penumbral region. A horizontal magnetic flux tube representing a penumbral filament is placed in a stratified atmosphere containing the background magnetic field that is directed in a relatively vertical direction. Between the flux tube and the background field there forms the intermediate region in which the magnetic field has a transitional configuration, and the simulation shows that in the intermediate region magnetic reconnection occurs to produce a clear jet- like structure as suggested by observations. The result that a continuous distribution of magnetic field in three-dimensional space gives birth to the intermediate region producing a jet presents a new view about the mechanism of a penumbral microjet, compared to a simplistic view that two field lines, one of which represents a penumbral filament and the other the background field, interact together to produce a jet. We also discuss the role of the intermediate region in protecting the structure of a penumbral filament subject to microjets.

• Journal of the Korean Vacuum Society
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• v.8 no.2
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• pp.172-179
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• 1999

The axial distributions of plasma density in a helical resonator plasma with the external magnetic field have been measured using Langmuir probes. Net RF power is set to 200W and chamber pressure is varied from 0.4 mTorr to 100mTorr there are three kinds of eternal magnetic field structure applied on the helical resonator plasma. One is a uniform magnetic field, the second is a positive gradient magnetic field and the third is a negative gradient magnetic field. In the three magnetic field structures, the negative gradient magnetic field is found to show the highest increase in plasma density on the substrate compared with other magnetic structures. Plasma density profile in helical resonator is well consistent with electromagnetic field pattern obtained by computer simulation. It is also found that axial magnetic fields do not affect plasma density distribution in the plasma reactor region, but induce the increase of plasma density in the process chamber region. In order to avoid the nonuniformity of radial density profile, weak magnetic fields under 100G are applied.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2000.11b
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• pp.254-261
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• 2000

Soil chemical properties, relief of field surface, SPAD values and grain yield were investigated in a 0.5ha paddy field in 1999 to obtain basic field information for precision agriculture. Descriptive statistics of field information showed that the coefficient of variation ranged from 1.63% to 38.7%. Field information showed a high spatial dependence for within paddy field. The ranges of spatial dependence were from 15m to 60m, respectively. Kriged maps enable the visualization and comparison the spatial variability of field information. The causes of spatial variability of the field information could be explained rationally by a field management map. Grain yield was negatively correlated with pH, relief values, whereas, was positively correlated with total C, total N, C/N ratio, mineralizable N, available P and exchangeable K, Ca at the significant level of 1 %.

• The Journal of the Korea Contents Association
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• v.9 no.9
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• pp.226-234
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• 2009

This study aims to research the influencing factors of field education outcome. This study is to help the social welfare subject find out the field education orientation. Following is the result brought out from the research. First, it was found that the evaluation of field manager, field agency and field education outcome working in social welfare agencies had no meaningful statistical difference. Second, the results of regression analysis showed that the evaluation of field manager and field agency had influenced on field education outcome. Along with major of the study, implications for expanding opportunities of continuing educations for managers in non-profit organization are discussed.

• Journal of the Korea Institute of Military Science and Technology
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• v.25 no.4
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• pp.339-346
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• 2022

The importance of stealth technology is increasing in modern warfare, and Radar Cross Section(RCS) is widely used as an indicator of stealth technology. It is useful to measure RCS using an image-based near-field to far-field transformation algorithm in short-range monostatic conditions. However, the near-field measurement system requires a longer measurement time compared to other methods. In this work, it is proposed to reduce the measured data using an interpolation method in azimuth angular domain. The calculated far-field RCS values according to the sampling rate is shown, and the performance of the algorithm applied with interpolation in the angular domain is presented. It is shown that measurement samples can be reduced several times by using the redundancy in the angular domain while producing results similar to the conventional method.