• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.1
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• pp.52-59
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• 2007

A field mill capable of measuring the magnitude and polarity of electric fields at the ground level was studied to apply to a lightning warning system as a sensor. We designed and fabricated a planar-shutter type field mill with a rotating-vanes. A calibration of the field mill was performed in a vertically symmetrical arrangement which consists of two equal size parallel round plates to form a homogeneous electrical fields. The sensitivity of the field mill was adjusted at 0.5[V/kV/m], and this covers a ranges from 200[V/m] to 20[kV/m]. After the calibration experiment, the field mill was installed on the roof of a building to measure the changes of electric field intensity caused by thunderclouds. During the period from July 1. 2006 to July 15. 2006, the electric field intensity was recorded a ranges of $+2[kV/m]{\sim}-6[kV/m]$ depending on generation, extinction and movement of thunderclouds. From the actual test on the ground it is confirmed that the field mill has a good performance necessary for the measurement of DC electric fields.

• Journal of the Korean Geophysical Society
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• v.2 no.1
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• pp.27-38
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• 1999

The errors between track segments or at the cross-over points of shipborne gravity were successfully reduced by applying a cross-over error adjustment technique using satellite gravity. The integration of shipborne and satellite altimeter-implied free-air gravity anomalies after the cross-over error adjustment resulted in a high resolution gravity map which contains both short and long wavelength components. The successful adjustment of the cross-over errors in the shipborne gravity using the satellite gravity suggests that the shipborne gravity can be combined with the satellite anomalies characterized by a stable and long wavelength component. The resulting free-air anomaly map is evenly harmonized with both short and long wavelength anomalies. Thus the corrected anomaly map can be better used for the geological interpretation. Free-air anomalies with more than 140 mGal in total variations generally correspond to the seafloor topographic changes in their regional patterns. A series of gravity highs are aligned from the Korea Plateau to the Oki Island, which are interpreted to be caused by seamounts or volcanic topographies. The gravity minima along the western and southern shelf edge are associated not only with the local basement morphology and thick sediment fill at the continental margin, but also possibly with the crustal edge effect known for passive continental margins. Series of NE-trending linear anomalies are possibly caused by a swarm of volcanic intrusions followed the initial opening of the Ulleung Basin. The linear high anomalies in the Ulleung Plateau are terminated by the straightly NNW-trending anomalies with a sharp gradient in its western boundary which indicates a fault-line scarp. The opposite side adjoined with the fault-line scarp shows no correlation with the fault-line scarp in geometry indicating that the block might be horizontally slided from the north. A gravity high in contrast to the deepening in seafloor toward the northeastern central Ulleung Basin is probably responsible for the thin crust and shallow seated mantle. The gravity minima along the western and southern shelf edge are associated not only with the local basement morphology and thick sediment fill at the continental margin, but also possibly with the crustal edge effect known for passive continental margins. Series of NE-trending linear anomalies are possibly caused by a swarm of volcanic intrusions followed the initial opening of the Ulleung Basin. The linear high anomalies in the Ulleung Plateau are terminated by the straightly NNW-trending anomalies with a sharp gradient in its western boundary which indicates a fault-line scarp. The opposite side adjoined with the fault-line scarp shows no correlation with the fault-line scarp in geometry indicating that the block might be horizontally slided from the north. A gravity high in contrast to the deepening in seafloor toward the northeastern central Ulleung Basin is probably suggestive of a thin crust and shallow seated mantle.

• Bulletin of the Korean Space Science Society
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• 2011.04a
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• pp.22.3-22.3
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• 2011

최근 일본 동북부 지역에서 리히터 규모 9.0의 대지진이 발생하였으며, 이로 인하여 일본 본토 및 주변지역의 지각 이동이 관측되고 있다. 한반도의 경우 일본에 비해 지진에 비교적 안정적이라고 알려져 있으나 활성단층대가 존재하고 리히터 규모 3.5이하의 지진이 년간 30~40여 차례 발생하고 있다. 이 논문에서는 위성항법기반 재난/재해 감지 연구의 일환으로써 일본 대지진이 한반도 지각 이동에 미치는 영향을 분석하였다. 현재 국내에는 100여개의 GPS 상시관측소가 운영되고 있으며, 다양한 선행 연구를 통해 동남쪽 방향으로 2~3cm/yr 속도로 이동하고 있는 것으로 알려져 있다. 이 논문에서는 이러한 선행 연구 결과를 바탕으로 일본 지진 발생 전후의 국내 GPS 상시관측소 좌표 변동량을 분석하였다. GPS 자료 처리를 위하여 GIPSY-OASIS 5.0을 이용하였으며, 안테나 위상중심변동량(phase center variation), 해수조석하중(Ocean tidal loading)에 의한 지각변동량을 보정하였다.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1990.10a
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• pp.174-178
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• 1990

• Proceedings of the Korean Nuclear Society Conference
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• 2001.05a
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• pp.447.1-447
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• 2001

• Proceedings of the Korean Institute of Landscape Architecture Conference
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• 2011.10a
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• pp.72-76
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• 2011

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2011.06a
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• pp.193-193
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• 2011

• Electric Engineers Magazine
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• v.207 no.11
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• pp.30-35
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• 1999

본고에서는 최근, 신형 피뢰침 설비로 많이 설치되고 있는 선행 스트리머 방사형 피뢰침 설비의 접지에 대하여 기술한다. ESE 피뢰침 설비의 접지도 수뢰된 뇌격전류를 대지로 방류하는 시스템이므로 기본적으로 일반 피뢰침의 접지와 동일하다.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 1998.06a
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• pp.292.2-293
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• 1998

• Journal of Bio-Environment Control
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• v.17 no.1
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• pp.26-31
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• 2008

This experiment were conducted to investigate the response of growth and yield of potato after transplanting of plug seedlings 'Superior' and 'Dejima' produced at different plug cell size (105, 162, and 288) and photoperiod (8/16, 12/12, and 16/8, day/night) for 20 days in controlled plant growth system. Growth and relative growth rate of plug seedling 'Superior' was affected by plug cell size and photoperiod at 7weeks after transplanting. Tuber weight of 'Superior' was increased as cell size and photoperiod increased. That of 'Dejima' was highest in 105 cell and different with photoperiod. At 90 days after transplanting, tuber weight ($258.9{\sim}471.9\;g/plant) of 'Superior' was high in 105 and 162 cell size and 16/8 hr photoperiod. That ($278.2{\sim}428.0\;g/plant$) of 'Dejima' was high in 105 cell size, but was not different with photoperiod. The number of tuber per plant was $2.6{\sim}6.9$ of 'Superior' and $2.2{\sim}3.6$ 'Dejima'. Tuber number per plant was not significantly different with cell size and photoperiod. The large tuber over 80 g was $32.0{\sim}50.9%$ of 'Superior' and $41.0{\sim}56.7%$ of 'Dejima'. The large tuber in 'Superior' and 'Dejima' lowered as the cell size decreased. The large tuber of 'Superior' increased as photoperiod increased, but that of 'Dejima' was not differed. As the results, the optimal plug cell size and photoperiod of potato seedling is considered to be below 162 cell and over 12 hr of photoperiod.