• Title/Summary/Keyword: Optoelectronic

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Chromogenic and Fluorogenic Polymer Systems for Optical Sensing and Patterning

  • Lee, Taek-Seung;Kim, Tae-Hyeon;Kim, Tae-Hoon;Choi, Moon-Soo;Kim, Hyung-Jun;Kwak, Chan-Gyu;Lee, Jung-Hyo;Lee, Chi-Han
    • Proceedings of the Polymer Society of Korea Conference
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    • 2006.10a
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    • pp.175-175
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    • 2006
  • Considering the number of chemosensors that have been developed for the sensing of metal ions, only a few chemosensors for fluoride anion have been described in the literature that are based on fluorescent or chromogenic responses. We performed colorimetric anion sensing based on the binding of anion analytes with hydrogen donor group in polymer backbone resulting in naked-eye color change and fluorescent quenching. Our challenges using hydrogen donor moiety was designed effectively are continuing in order for high selectivity and sensitivity for ultimate applications such as fluid solution sensing in biomolecules and gas vapor sensing.

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Self-Consistent Subband Calculations of AlGaN/GaN Single Heterojunctions

  • Lee, Kyu-Seok;Yoon, Doo-Hyeb;Bae, Sung-Bum;Park, Mi-Ran;Kim, Gil-Ho
    • ETRI Journal
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    • v.24 no.4
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    • pp.270-279
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    • 2002
  • We present a self-consistent numerical method for calculating the conduction-band profile and subband structure of AlGaN/GaN single heterojunctions. The subband calculations take into account the piezoelectric and spontaneous polarization effect and the Hartree and exchange-correlation interaction. We calculate the dependence of electron sheet concentration and subband energies on various structural parameters, such as the width and Al mole fraction of AlGaN, the density of donor impurities in AlGaN, and the density of acceptor impurities in GaN, as well as the electron temperature. The electron sheet concentration was sensitively dependent on the Al mole fraction and width of the AlGaN layer and the doping density of donor impurities in the AlGaN. The calculated results of electron sheet concentration as a function of the Al mole fraction are in excellent agreement with some experimental data available in the literature.

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UV molding of Microlens Array on the Simulated Optoelectronic Device (모사 광전자 소자 상에 적용한 마이크로렌즈 어레이의 UV 성형)

  • 구승완;김석민;강신일;손현주
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2003.10a
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    • pp.377-380
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    • 2003
  • Recently, demand of digital products with optoelectronic device is increasing rapidly. A microlens array is applied to improve optical efficiency on optoelectronic device, and it is usually fabricated by photolithography and reflow process after planarization layer coating process. UV molding process is more suitable for mass production of high quality microlens array than photolithography and reflow process. In the present study, microlens array was fabricated on the simulated optoelectronic device with planarization layer by aligned UV molding process. The shape of replicated microlens was measured, and the section image of molded part was examined.

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Visible Light Identification System Using Optoelectronic Feedback of A Lighting LED (조명용 LED의 광전궤환을 이용한 가시광 무선인식장치)

  • Lee, Seong-Ho
    • Journal of Sensor Science and Technology
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    • v.20 no.3
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    • pp.193-198
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    • 2011
  • In this paper, we used optoelectronic feedback to generate the carrier frequency for the ASK modulation of a lighting LED. A solar cell was used for photo-detector in the feedback circuit, and the LED light was ASK modulated by controlling the ON/OFF state of the switch that is installed in the feedback loop. The oscillation frequency of the optoelectronic feedback loop was about 50 kHz and the data rate of the ASK modulation was 9.6 kbps. In experiments, the optoelectronic feedback circuit was used for the ASK modulation of a lighting LED in the transponder of a visible light identification system, and data exchange between the transponder and the reader was successfully carried out.

Enhanced Giant Magnetoelectric Effect in Laminate Composites of FeCuNbSiB/FeNi/PZT

  • Wen, Yumei;Wang, Dong;Li, Ping
    • Journal of Magnetics
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    • v.16 no.4
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    • pp.398-402
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    • 2011
  • A novel laminate composite of FeCuNbSiB/FeNi /PZT is proposed, where FeCuNbSiB has a permeability of around 100000, which is much larger than that of FeNi. The high-permeability FeCuNbSiB was laminated with piezomagnetic FeNi rather than attached to its ends. It is expected that the effect produced by the high permeability will act on the whole of the piezomagnetic layer. While a FeNi layer was laminated with a FeCuNbSiB layer, the strong demagnetization produced by the latter was expected to be imposed on the FeNi layer as well as the applied fields. The distribution of applied fields was altered by the high-permeability material (both bias and ac field) and the field variation positively contributed to the ME effect in piezomagnetic/piezoelectric composites. Thus the ME voltage coefficient along with the field sensitivity were improved.