• Title/Summary/Keyword: university system

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Thermal stability analysis of interferometric snapshot spectro-polarimeter (간섭기반 스냅샷 분광편광위상측정의 열 안정성 분석)

  • Choi, Inho;Dembele, Vamara;Paul, Madhan Jayakumar;Choi, Sukhyun;Kim, Junho;Baek, Byung-Joon;Kim, Daesuk
    • Journal of the Semiconductor & Display Technology
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    • v.17 no.3
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    • pp.70-74
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    • 2018

  • In typical spectroscopic ellipsometry, the optical and geometrical properties of thin film and nano pattern can be obtained by measuring the polarization state of light reflected/transmitted from the object by rotating a analyzer or a compensator. We proposed a snapshot spectroscopic ellipsometric system based on a modified Michelson interferometer to overcome the time-consuring measurement principle due to rotating part. The proposed system provides spectral ellipsometric parameters (psi, delta) in real time by using a single spectral interference signal generated in the interferometric polarization module. However, it has a long-term stability problem resulting in delta(k) drift. In this paper, it is experimentally proved that the drift problem is caused by anisotropic refractive index change of the beam intersection layer in beam splitter of interferometer.

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A Study on the Customer Voltage Characteristic of Distribution System with Large Scale PV (대용량 태양광발전이 연계된 배전계통의 수용가 전압 특성해석에 관한 연구)

  • Kim, Byung-Ki;Ryu, Kyung-Sang;Kim, Chan-Hyeok;Rho, Dae-Seok
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.1
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    • pp.29-36
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    • 2013

  • This paper deals with the analysis of the customer voltage characteristic in distribution system interconnected with large scale PV system. There would be many power quality issues which are caused by reverse power flow of PV system interconnected with distribution system. In order to analyze the effect of PV system on the customer voltage, detailed modeling method of distribution system and modified modelling method of PV system are proposed using PSCAD/EMTDC in this paper. So far, less than dozens KW of PV system can be simulated with the existing modelling method. Therefore, a new modeling method which can simulate the large scale PV system is proposed by considering the relationship equation on the phase and voltage in the current control algorithm. From the simulation result of proposed modelling method, it is confirmed that an optimal operation method in distribution system is suggested by analyzing the effect of PV system on customer voltage.

  • https://doi.org/10.5370/KIEE.2012.62.1.029 인용 PDF KSCI