• 전자공학회논문지
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• 제53권1호
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• pp.29-35
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• 2016

집적광학 $Ti:LiNbO_3\;1{\times}2$ Y-fed Balanced-Bridge 마하젠더 간섭기(YBB-MZI) 구조에 다이폴 패치 아테나를 적용해서 $1.3{\mu}m$ 파장대역에서 동작하는 전계센서를 구현하였다. BPM 전산모사를 통해서 소자 설계 및 동작성능을 검증하였고, $1.3{\mu}m$ 파장대역에서 ~16.6 V 스위칭전압과 이에 대응해서 소멸비는 ~14.7 dB로 측정되었다. 10 MHz, 50 MHz 각각의 주파수에서 감지 가능한 최소 전계는 1.12 V/m, 3.3 V/m로 측정 되었으며, 이에 대응되는 각 주파수에서 ~22 dB, ~18 dB의 다이나믹 범위가 측정되었다. 제작된 센서는 0.29~29.8 V/m 범위의 전계세기에 대해서 선형응답 특성을 나타내었다.

• The Plant Pathology Journal
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• 제35권3호
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• pp.234-242
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• 2019

Thirty-four strains of bacteria were isolated from Phellodendron amurense. Using Nectria haematococca as an indicator strain, the best strain, B18, was obtained by the growth rate method. The morphological, physiological and biochemical characteristics of strain B18 and its 16S DNA gene sequence were identified, and the biocontrol effect of strain B18 was assessed in pot and field tests, as well as in a field-control test. Drilling methods were used to determine the antibacterial activity of metabolites from strain B18 and their effects on the growth of pathogen mycelia and spores. The best bacteriostatic rate was 85.4%. B18 can hydrolyse starch and oxidize glucose but does not produce gas; a positive result was obtained in a gelatine liquefaction test. According to 16S DNA gene sequencing, strain B18 is Bacillus methylotrophicus (GenBank accession number: MG457759). The results of pot and field-control trials showed 98% disease control when inoculating $10^8cfu/ml$ of the strain. The disease control effect of the B18 culture liquid (concentrations of $10^8$, $2{\times}10^6$, $10^6$, $5{\times}10^5$ and $2.5{\times}10^5cfu/ml$) in the field-control test was higher than 80%, and the cure rate of the original delivery solution was 96%. Therefore, in the practical forestry production, a $2.5{\times}10^5cfu/ml$ culture liquidshould be applied in advance to achieve good control effects.

• 한국초전도ㆍ저온공학회논문지
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• 제5권1호
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• pp.97-101
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• 2003

When HTS tapes are used in power application, they are used by winding form, such as, a pancake and a solenoid. When AC current is applied to the coil, Ac magnetic field is generated in winding. This AC magnetic field acts as an external magnetic field and makes loss. In this paper the radial magnetic field component ($B_r$) and the axial magnetic field component ($B_z$) in a pancake and a solenoid were calculated by numerical analysis method and compare with measured value. AC losses of a short sample were calculated by Norris equation and n numerical analysis based on Brandt equation. AC losses of the pancake coil and the solenoid coil were also calculated.

• 한국통신학회논문지
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• 제36권2B호
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• pp.141-147
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• 2011

본 연구에서는 국내 FM 방송 가용주파수 확보 가능성을 확인하기 위하여 600kHz 채널이격 간격에 대한 동일 송신소 이격실험을 실시하였다. 통일 송신소에서 주파수를 600kHz로 이격할 경우, 수신기를 통한 주관적 음질평가, 전계강도 등의 특성이 비교적 양호한 것으로 평가되어 사전 시뮬레이션 및 충분한 Field Test 등의 사전 분석을 통해 사용할 수 있음을 확인하였다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제48권6호
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• pp.309-315
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• 1999

Coupling loss is generated by the time-varying external magnetic field in the normal matrix of the multi-filamentary HTS tape. This paper calculates the coupling loss in the HTS tape. Analytic calculation of the coupling loss cannot consider the effect of the different shapes and the arrangement of the filaments. Numerical calculation by using finite element method and analytic calculation of the coupling loss have been done in this paper and results of two calculations have been compared. Transverse magnetic field and longitudinal magnetic field were considered as the external field.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권10호
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• pp.501-506
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• 2003

A Superconducting Rotary Machine (SRM) is characterized by an air-cored machine with its rotor iron and stator iron teeth removed. For this reason, the SRM is featured by 3D magnetic flux distribution, which decreases in the direction of axis. Therefore, 3D magnetic field analysis method is required to know about characteristic of magnetic field distribution of SRM. In this paper, 3D flux distribution of SRM is calculated by analytical method. The magnetic field distribution of the field coils is calculated by Biot-Savart equation. The magnetic core is represented by magnetic surface polarities. This paper describes the combined use of above methods for the total field computation, and compares results of analytical method and 3D FEM(Finite Element Method).

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1658-1660
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• 1994

This paper describes the measurement system of the magnetic field waveforms generated by lightning return strokes. The frequency bandwidth of magnetic field measurement system is from 270[Hz] to about 2.3 [MHz]. As the application experiment, the magnetic field generated by simple impulse and oscillating impulse currents, which are measured by a current transformer (Tek. AM503), is observed by the trial magnetic field measurement system. The obtained results are agreement with each other. A typical magnetic field waveform associated with lightning return strokes was recorded and presented.

• 한국통신학회논문지
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• 제39B권1호
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• pp.44-52
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• 2014

본 연구에서는 마이크로스립 패치 안테나의 접지 면으로 버섯 형태 EBG(Electromagnetic Band Gap)를 사용할 경우의 근거리 장(near field) 원거리 장(far field) 방사 지향성(radiation directivity)의 영향을 연구하였다. 버섯 모양 EBG의 분산 곡선 특성을 이용하여 주어진 버섯모양 EBG의 금지대역(band gap) 2.36-2.85[GHz]를 계산하고, 금지대역 영역에 속하는 주파수로 동작하는 2-층의 버섯 형태 EBG 마이크로스트립 안테나(2.45GHz)를 설계하였다. EBG를 접지 면으로 사용한 마이크로스트립 안테나의 성능향상을 확인하기위하여 PEC(Perfect Elecric Conductor)를 접지 면으로 사용한 동일한 안테나 경우와 성능차이를 비교하였다. EBG를 사용할 경우 유전체와 도체의 경계면에서 발생하는 표면파(Surface Wave)를 효과적으로 억제하여 지향성이 약 2.74dB 정도 향상된 것을 알 수 있었다.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 1999년도 High Temperature Superconductivity Vol.IX
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• pp.178-184
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• 1999

We have measured I-V characteristics of Bi$_2Sr_2CaCu_2O_{8+{\delta}}$ mesa containing a small number of intrinsic stacked Josephson junctions in a magnetic field. We fabricated mesa with an area of 40${\times}$40 ${\mu}$m$^2$ containing 3${\sim}$20 intrinsic junctions. We applied magnetic field perpendicular to He CuO$_2$ planes up to 5T. We observed flux-flow branches and flux-flow steps in the I-V characteristics which might be due to collective motion of Josephson vortices in the long junction limit. In a parallel field, critical current I$_c$ varies as I$_c$(B) ${\sim}$ exp(-B/B$_0$), where B$_0$ is about 2T, which is consistent with the theoretical model. DC and AC intrinsic Josephson effects are also discussed.

• 한국전기전자재료학회논문지
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• 제14권3호
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• pp.207-214
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• 2001

The conductive polymers, polyaniline (PANI) emeralidin base and 3,4-polyethylene dioxythiophene(PEDOT) were synthesized and coated on the PET film dealt with acryl type primer to study the electromagnetic shielding effectiveness. When both PANI and PEDOT were coated on the PET film dealt with acryl type priemer, their surface properties such as he adhesive increased. For PANI, when blended with the binder such as PMMA, it adhesive and surface hardness increased, too. The visible light transmittance decreased, while the electromagnetic shielding effectiveness increased, when coated thickness of PANI and PEDOT increased. For PANI, the electromagnetic shielding effectiveness increased as its surface resistance decreased. For PANI, when the surface resistance was 140 Ω/$\square$, the shielding effectiveness was found to be 11 dB in the far field, and 13 dB in the near field at 1 GHz. For PEDOT, when the surface resistance was 200 Ω/$\square$, the shielding effectiveness was found to be 3 dB in the far field, and 7dB in the near field.