• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.197-197
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• 2012

염료감응형 태양전지 (DSSC)는 다양한 태양전지 중, 가장 환경친화적이고, 생산단가도 낮을 뿐만 아니라 다양한 색상과 투광성을 확보할 수 있어 많은 연구가 진행되어왔다. 하지만 액체 전해질을 사용하는 기존 염료감응형 태양전지는 높은 휘발성과 열 팽창 수축에 따른 전해질 누액의 문제점으로 인하여 최근에는 고체전해질을 이용한 염료감응형 태양전지의 개발이 활발히 이루어지고 있다. 본 연구에서는 스크린 프린팅법을 이용하여 TiO2 광전극을 코팅하고 Mg(OH)2를 솔-젤법을 이용하여 스핀 코팅 하였다. 이후에 $500^{\circ}C$에서 1시간동안 열처리를 통해 MgO 나노 코팅막을 형성하여 고체 박막 태양전지(solid state dye sensitized solar cells)을 제작하였다. MgO 나노 코팅막의 특성은 솔라시뮬레이터를 이용하여 I-V 곡선, transient Voc, dark current를 측정하였고, UV0vis spectroscopy를 이용하여 염료흡착량을 분석하여 코팅막과 효율간의 상관관계를 평가하였다.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.36T no.3
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• pp.72-78
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• 1999

The frequency characteristics of surface corona discharge from the electrodes on the ceramic substrate ozonator were investigated. The frequency characteristics of dark current were compared with that of corona discharge. Switching frequency which was the fraction of resonant frequency was found to be effective for corona discharge. This is regarded to distort the electric field distribution on the discharge plate which is essential for corona discharge. The measurement showed the efficiency of 28mg/W ozone generation when the switching frequency was 1/5 of the resonant frequency.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.50.4-51
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• 2015

Current and planned deep multicolor wide-area cosmological surveys will map in detail the spatial distribution of galaxies and quasars over unprecedented volumes, and provide a number of objects with photometric redshifts more than an order of magnitude bigger than that of spectroscopic redshifts. Photometric information is statistically more significant for studying cosmological evolution, dark energy, and the expansion history of the universe at a fraction of the cost of a full spectroscopic survey, but intrinsically carries a bias due to noise in the distance estimates. We provide convolution- and deconvolution-based algorithms capable of removing this bias -- thus able to exploit the full cosmological information -- in order to reconstruct intrinsic distributions and correlations between distance-dependent quantities. We then show some direct applications of our techniques to the VIMOS Public Extragalactic Redshift Survey (VIPERS) and the Sloan Digital Sky Survey (SDSS) datasets. Our methods impact a broader range of studies, when at least one distance-dependent quantity is involved; hence, they will be useful for upcoming large-volume surveys, some of which will only have photometric information.

• Bulletin of the Korean Space Science Society
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• 2011.04a
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• pp.28.1-28.1
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• 2011

Radiation-induced displacement damage which has caused the increase of the dark current in the focal plane adopted in the Ozone Monitoring Instrument (OMI) was studied in regards of the primary protons and the secondaries generated by the protons in the orbit. By using the Monte Carlo N-Particle Transport Code System (MCNPX) version 2.4.0 along with the Stopping and Range of Ions in Matter version 2010 (SRIM2010), effects of the primary protons as well as secondary particles including neutron, electron, and photon were investigated. After their doses and fluxes that reached onto the charge-coupled device (CCD) were examined, displacement damage induced by major sources was presented.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.11a
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• pp.57-58
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• 2009

최근 MPEG에서 HD(High Definition) 해상도 이상의 초고해상도 비디오를 위한 HVC(High-performance Video Coding) 표준화에 대하여 논의가 되고 있다. 이런 흐름 속에서 ETRI에서 보유중인 베리어 방식의 CCD를 사용하여 NHK에서 제작된 RG1G2B 4K 영상은 dark current error, bias error, flat error 등에 의한 영상 자체의 열화가 많아 HVC 연구를 위한 영상으로 사용되기에는 무리가 많다. 가장 이상적인 해결방안은 NHK에서 제작한 카메라 자체에 열화제거를 위한 장치들을 설치하여 규칙적인 열화를 제거한 영상을 확보하는 것이지만, 특수 제작된 카메라여서 이 방법은 불가능하다. 본 논문은 이 NHK의 영상을 wavelet 기반의 denoise filter를 응용하여 영상의 열화를 일정부분 제거하면서 영상의 디테일이 최대한 유지되도록 하여, 기존의 영상보다 깔끔한 8K UHD 영상을 획득하는 방안을 제시한다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07b
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• pp.1022-1025
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• 2002

This paper presents the reliability of planar InP/InGaAs avalanche photodiodes (APD's) with recess etching, which is very crucial for the commercial 10-Gb/s optical receiver application. A versatile design for the planar InP/InGaAs APD's and bias-temperature tests to evaluate long-term reliability at temperature from 200 to $250^{\circ}C$. The reliability is examined by accelerated life tests by monitoring dark current and breakdown voltage. The lifetime of the APD's is estimated by a degradation activation energy. Based on the test results, it is concluded that the planar InP/InGaAs APD's with recess etching shows the sufficient reliability for practical 10-Gb/s optical receivers.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.444-447
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• 2004

SNR(Signal to Noise Ratio) is one of the most important performance for the electro-optical camera system. This paper shows not only the SNR analyses for the MSC system, which is the payload in the KOMPSAT2 satellite, but also the trials for its improvement in the electronics circuit design. The MSC deals with one panchromatic band and four multi-spectral bands. The SNR analyses are performed based on the MSC design for the each band and assuming that the defined radiance reached directly to the sensor entrance pupil. In the SNR calculation, shot noise, dark current noise, analog electronics noise and ADC quantization noise are considered as noise sources. In these noise sources, especially, the electronics noise depends on the camera electronics design. This paper shows the camera electronics design to increase SNR and its test results as well as the SNR analyses.

• Proceedings of the KSRS Conference
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• 2006.03a
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• pp.315-318
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• 2006

Pushbroom 방식의 CCD 영상에서 발생하는 pixel들 사이의 Non-uniformity 원인은 CCD pixel 면적의 차이, Dark current 영향, Output amplifier 차이, input radiance의 차이 등과 같은 CCD의 특성에 의해 발생하게 되며, CCD의 특성에 의해 발생되는 pixel사이의 상대복사량 차이인 Non-uniformity errors은 위성영상에서 줄무늬의 일차적 원인이 된다. 이러한 CCD의 상대복사보정을 위해서는 일차적으로 CCD의 특성을 잘 파악할 수 있는 지상에서 보정 값이 계산되어져야 하며 위성발사 후 보정 값이 다시 update 되어야 한다. 본 연구에서는 다목적실용위성2호의 상대복사보정을 위한 준비로서, 지상에서 만들어진 MSC CCD PAN1 영상과 Pushbroom 방식의 다목적실용위성1호 영상을 시험자료로 이용하여 pixel 사이의 줄무늬를 제거하기 위한 상대복사보정을 수행하였다.

• Proceedings of the KSRS Conference
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• v.1
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• pp.60-63
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• 2006

Geostationary Ocean Color Imager (GOCI) is under development to provide a monitoring of oceancolor around the Korean Peninsula from geostationary platforms. It is planned to be loaded on Communication, Ocean, and Meteorological Satellite (COMS) of Korea. In this paper radiometric calibration concept of the GOCI is introduced. The GOCI radiometric response is modeled as a nonlinear system in order to reflect a nonlinear characteristic of detector. In this paper estimation approaches for radiometric parameters of GOCI model are discussed. For the GOCI, the offset signal depends on each spectral channel because dark current offset signal is a function of integration time which is different from channel to channel. The offset parameter can be estimated by using offset signal measurements for two integration time setting is described.

• 한국태양에너지학회:학술대회논문집
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• 2008.04a
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• pp.247-251
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• 2008

In this paper. we analyze electrical characteristics of photovoltaic module according to mechanical load test. Using the equipment for giving load on the surface of module, dark current-voltage is measured. By varying load from 0kg to 206kg, slight different I-V curve is detected. From this, reduced shunt resistance is roughly calculated and micro crack is assumed to be happened. system Through this experiment, periodic external force on PV module might give an negative effect. The detailed analysis is described in the following paper.