• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.133-134
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• 2008

이 논문에서는 $SiN_x$의 band gap 차이를 이용하여 MIS 구조의 메모리 소자를 제작하고 이를 분석하였다. $SiN_x$ 박막은 증착 가스비에 따라 다양한 band gap을 가지게 된다. 본 실험에서는 n-type 단결정 실리콘 기판위에 $SiH_4/NH_3$ 가스를 혼합하여 $SiN_x$ 박막을 증착하고, UV-Vis Spectrophotometer 장비를 이용하여 band gap을 구하였다. 큰 band gap을 갖는$SiN_x$ 박막을 블로킹 층에, 작은 band gap을 작는 $SiN_x$ 박막을 전하 저장 층에 사용하였다. 제작된 NNO 구조일 소자는 7.6 V의 hysteresis roof 폭과 1000초 후에 88.6 %의 retention 값을 갖는 우수한 메모리 특성을 보였다.

• Korean Journal Plant Pathology
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• v.12 no.2
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• pp.191-196
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• 1996

위축, 황화, 총생 증상 등 전형적인 병징을 나타내는 phytoplasma에 감염된 식물에서 phytoplasma만을 특이적으로 검출하기 위하여 polymerase chain reaction(PCR) 방법을 이용하였다. Phytoplasma의 16S rRNA gence의 DNA 단편을 증폭하기 위하여 1.4 kb primers (forward, 5` -GTTGATCCTGGCTCAGGATT-3` 와 reverse, 5` -AACCCCGAGAACGTATTCACC -3`)를 사용하여 증폭한 결과, phytoplasma에 이병된 오동나무, 라일락 및 미역취에서는 약 1.4 kbp의 위치에서 특이 band가 검출되었으나 control로 사용한 건전주에서는 어떠한 band 검출되지 않았다. 위의 결과를 재확인 하기 위하여 약 0.5 kb의 primers(forward, 5` -ACGAAAGCGTGGGGAGCAAA-3` 와 reverse, 5` -GAAGTCGAGTTGCAGACTTC-3`)를 사용하여 증폭한 결과, 0.5 kb의 위치에서 특이 band가 검출되었으나 control로 사용한 건전주에서는 어떠한 band도 검출되지 않았다. Phytoplasma에 이병된 식물의 PCR 반응산물을 제한효소인 AluI으로 처리하 sruf과, 오동나무와 라일락에서는 동일한 band pattern을 나타내어 서로 유연관계가 가까운 phytoplasma인 것으로 생각되며, 미역취에서는 이들과는 다른 band pattern을 나타내어 오동나무와 라일락의 phytoplasma와는 유연관계가 먼 것으로 추측된다.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.8
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• pp.368-374
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• 2002

In this paper, we introduce a procedure to obtain a equivalent circuit of comb-line band pass filter. By employing equivalent circuits of each asymmetrical coupled line. we composed the full equivalent circuit of comb-line bandpass filter and derived simple design equations for extracting each line's impedance. To show the validity of design equations, we simulated and fabricated a planar type comb-line bandpass filter, which has center frequency 1.8㎓, band-width 50㎒ and four resonators. The resulting filter is very compact, have broad stop band with the second pass band centered at four times the center frequency of the first pass band. The experimental results show exact performances of design specification.

• Korean Journal of Remote Sensing
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• v.29 no.6
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• pp.631-644
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• 2013

Significant Wave Height (SWH) data measured by satellite altimeters (Topex/Poseidon, Jason-1, Envisat, and Jason-2) were validated in the seas around Korea by comparison with wave height measurements from marine meteorological buoy stations of Korea Meteorological Administration (KMA). A total of 1,070 collocation matchups between Ku-band satellite altimeter data and buoy data were obtained for the periods of the four satellites from 1992 to the present. In the case of C-band and S-band observations, 1,086 matchups were obtained and used to assess the accuracy of satellite SWH. Root-Mean-Square (RMS) errors of satellite SWH measured with Ku-band were evaluated to roughly 0.2_2.1 m. Comparisons of the RMS errors and bias errors between different frequency bands revealed that SWH observed with Ku-band was much more accurate than other frequencies, such as C-band or S-band. The differences between satellite SWH and buoy wave height, satellite minus buoy, revealed some dependence on the magnitude of the wave height. Satellite SWH tended to be overestimated at a range of low wave height of less than 1 m, and underestimated for high wave height of greater than 2 m. Such regional characteristics imply that satellite SWH should be carefully used when employed for diverse purposes such as validating wave model results or data assimilation procedures. Thus, this study confirmed that satellite SWH products should be continuously validated for regional applications.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.1
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• pp.73-77
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• 2012

In this article, we designed a wide bandpass filter in order to apply microwave reflectometry for KSTAR. The proposed wide bandpass filter consists of a metamaterial structure which is to get a wide band, a lower insertion loss, and a high skirt. This is applied to VCO's output to enhance the linearity. A pass band is 18-28 GHz and the out of pass band is stopped over 20 dB. To confirm of the metamaterial, we suggest a dispersion diagram. The proposed filter in lower band and upper band of pass band is respectively a left handed and right handed characteristics. A group delay is below 0.5 ns.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.5
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• pp.461-466
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• 2012

This paper describes the development and test result of X-band Transmitter flight model(FM) of STSAT-3 by satellite research center(SaTReC), KAIST. The communication sub-system of STSAT-3 is consist of two different frequency band channels. S-band frequency is used for Telemetry & Command, and X-band frequency is used for mission data. Payload observations data in Mass Memory Unit (MMU) is modulated by QPSK modulator in X-band Transmitter, and then QPSK modulation signal is transmitted to antenna through transfer switch. In this Paper, we described the results of modulation, low-pass filter design, power amp development, and switch test. The FM XTU is delivered Spacecraft Assembly, Integration and Test(AIT) level through the completion of functional Test and environmental(vibration, thermal vacuum) Test successfully.

• Korean Journal of Environmental Biology
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• v.17 no.2
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• pp.209-215
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• 1999

Changes of malate dehydrogenase isozyme in oyster exposed to different temperature, pH and salinity were investigated by polyacrylamide gel electrophoresis. MDH isozyme in control group was separated into two bands on the positive side. In case of temperature and pH stress, MDH isozyme was separated into only one band after 12 hours exposure but two bands after 24, 48 hours exposure on the positive side. In case of salinity stress, after 12 hours exposure, MDH isozyme bands were separated into two bands in 5 ppt, 30 ppt and three bands in 10 ppt, 40 ppt concentration on the positive side. After 24 hours and 48 hours exposure case in salinity stress, MDH isozyme bands was separated into two bands on the positive side in all concentration. Activities of isozyme bands show their characteristics according to the condition of experiment. In conclusion, changes of MDH isozyme was a biochemical defense mechanism in oyster and result from effect of environmental stress to oyster.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.461.1-461.1
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• 2014

본 연구진에서는 기존에 Ag2S 양자점을 흡광층으로 활용하여 양자점 감응형 태양전지(QDSC)를 제작, 그 성능과 특징을 분석하여 발표한 바 있다. 기존 연구에서 제작된 Ag2S QDSC는 11 mA/cm2의 비교적 높은 광전류와 260 mV의 비교적 낮은 전압으로 인해 1.2%의 광전환효율 성능을 나타내는 것으로 보고되었다. 추후 연구로 진행된 본 결과에서는, 기존에 Single absorber로 사용된 Ag2S의 한계를 보완하기 위해 CdS를 도입하여 co-sensitization을 활용하였다. CdS는 약 2.3 eV의 밴드갭 에너지를 갖는 물질로, 1.1 eV의 밴드갭을 갖는 Ag2S에 비해 흡광 영역은 좁지만 그만큼 전자-정공 재결합을 억제할 수 있는 장점을 가지고 있다. 또한, 전도층으로 사용한 n-type 물질인 ZnO 나노선과의 밴드구조가 매우 적합하게 조화되어, ZnO/CdS/Ag2S 순서로 이종구조를 접합시켰을 때 세 물질의 Conduction band level과 Valence band level이 순차적으로 연결되는 cascade-shaped 밴드구조를 이루게 된다. 빛을 받아 Ag2S와 CdS에서 생성된 전자는 이 cascade 모양의 conduction band를 따라 순차적으로 ZnO로 잘 전달되게 되어, 효율 향상에 큰 도움을 주었다. 이런 장점들로 인해, CdS-Ag2S co-sensitized QDSC는 Ag2S QDSC에 비해 2배나 향상된 효율인 2.4%를 기록하였으며, 이는 IPCE spectrum 측정 등으로 근거가 뒷받침되었다.

• Bulletin of the Korean Space Science Society
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• 2004.10b
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• pp.312-315
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• 2004

In order to optimize the configurations of Ka-band transponder subsystem, the tradeoff design has been performed iterately with emphasis on the improving performances of the payload system as well as effectiveness of Satellite Communication (SATCOM) system operation. It is necessary to allocate performance to the transponder equipments and to keep providing the main services. It begins with analyzing the requirements and allocating performance parameters by establishing budgets for electrical and mechanical characteristics. In this paper, introduction of SATCOM system and finally optimized Ka-band transponder configuration that is to be used for preliminary design will be mainly presented.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.341-341
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• 2010

Electronic structure of Calix adsorbed on epitaxial graphene (EG) was investigated using high resolution photoemission spectroscopy (HRPES). Increasing the deposition of calix molecule, we found that EG becomes n-type doping using secondary edge measurement (work function change). As we observe bonding nature of O 1s peak, we found that single O 1s peak can be clearly distinguished in the spectra indicating equivalent adsorption state. Finally, we were able to control the band gap of EG using valence band spectra as we change the amount of calix molecule. In this study, we will propose the possibility of band gap modulation of EG using calix molecule.