• Title/Summary/Keyword: APD

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Development of Retina Photographing System and 16 Channels Image Acquisition System (망막 촬영 장치 및 16 채널 영상 획득 장치 개발)

  • 양근호
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.8 no.1
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    • pp.96-101
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    • 2004
  • In order to measure the retina thickness, there are to need the 3-D retina photographing and the high speed signal processing system. In this paper, we introduced the retina photographing system and the 16-channel high speed image data acquisition system. There are able to measure the retina thickness with sensing image the returned laser signal to APD sensor after there were projected the HeNe laser on retina. We developed the laser projection system to sense a reflected image of the retina using APD sensor, the 16-channel high speed A/D converter and PCI master interface card for image transmission into computer.

Design of Optical Peramplifier with InGaAs APD/GaAs MESFET (InGaAs APD/GaAs MESFET를 이용한 광 수신 전치증폭기의 설계)

  • 이영철;신철재
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.16 no.11
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    • pp.1071-1083
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    • 1991
  • In this paper, we describe the design and realization of optical preamplifier with InGaAs APD and GaAs MESFET. Optical preamplifier which is three stage trans-impedance circuit is analyzed in detail and realized in microstrip circuits. With the kmowledge of the InGaAs, GaAs MESFET and BJT, the performance of the optical is predicted by computer simulation and the theoretical predictions are compared with the experimental results. The designed hybrid MIC optical preamplifier exhibits a bandwith of 380MHz and a receiver sensitivity of -40. 6dBm at $1.55{\mu}m$ wavelength when operating at 565Mb/s with BER of $10^{-9}$.

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Measurements and Statistical Modeling of Electromagnetic Noise from Electric Train (도시전철에서 발생한 전자파잡음의 측정 및 통계적 모형)

  • 심환우;윤현보;백락준;우종우
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.6 no.7
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    • pp.37-47
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    • 1995
  • In this paper, we have measured eletromagnetic noises from eletcric trains and the measurment data are treated statisticlly for monig. In order to measure the noise of electric tran, we set up an automatic measuring system andd measured the magnetic field over 9 kHz ~ 30 MHz range and electric field over 30 MHz - 1, 000 MHz range. The computer controlled measurint system yields efficiently experimental APD (Amplitude Probability distribution) data each of national rail road and subway train. The measured APD curves are analysed in terms of sensitivity study of Middleton's model through 6-parameter variation. Optimal parameters are obtained from measured data using Composite Approximation Algorithm.

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Support Effect of Arc Plasma Deposited Pt Nanoparticles/TiO2 Substrate on Catalytic Activity of CO Oxidation

  • Qadir, Kamran;Kim, Sang Hoon;Kim, Sun Mi;Ha, Heonphil;Park, Jeong Young
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.02a
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    • pp.261-261
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    • 2013
  • The smart design of nanocatalysts can improve the catalytic activity of transition metals on reducible oxide supports, such as titania, via strong metal-support interactions. In this work, we investigatedtwo-dimensional Pt nanoparticle/titania catalytic systems under the CO oxidation reaction. Arc plasma deposition (APD) and metal impregnation techniques were employed to achieve Pt nanoparticle deposition on titania supports, which were prepared by multitarget sputtering and sol-gel techniques. APD Pt nanoparticles with an average size of 2.7 nm were deposited on sputtered and sol-gel-prepared titania films to assess the role of the titania support on the catalytic activity of Pt under CO oxidation. In order to study the nature of the dispersed metallic phase and its effect on the activity of the catalytic CO oxidation reaction, Pt nanoparticles were deposited in varying surface coverages on sputtered titania films using arc plasma deposition. Our results show an enhanced activity of Pt nanoparticles when the nanoparticle/titania interfaces are exposed. APD Pt shows superior catalytic activity under CO oxidation, as compared to impregnated Pt nanoparticles, due to the catalytically active nature of the mild surface oxidation and the active Pt metal, suggesting that APD can be used for large-scale synthesis of active metal nanocatalysts.

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Measurements and Statistical Modeling of Ignition Noise from Vehicle (자동차 점화계통에서 발생된 전자파 잡음의 측정 및 통계적 모형)

  • 김종호;윤현보;백락준;우종우
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.8 no.4
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    • pp.390-402
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    • 1997
  • The ignition noises from the vehicle are measured and the measurement data are statistically treated for modeling. The low-noise amplifier and band-pass filter are added between the receiver and the three axes antenna for low noise level measurement and the APD and PSD are measured in 800 MHz frequency range. The measured APD curves can be expressed in terms of sensitivity study of each model through 3(class A) or 6(Class B) parameters variation, and these optimal parameter can easily be calculated by using the Composite Approximation Algorithm. The selected APD parameter can be used for making the Data Base EM-environments and also applied to determine the output and sensitivity margin for the transmitter and receiver. 'Digital microwave transmission systems are equipped with equalizer against fading during multipath fading. In this paper, we proposed variable reference tap position equalizer that varies the reference tap according to fading type to archive better performance. We got the perf?mance improvement about 4~5 dB in MP condition and 2~3 dB in NMP condition from simulation results.

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Image Detecting System for Pinhole with Photoelectric Sensors (광전(光電)센서를 활용한 핀홀의 영상검출시스템)

  • Kang, Min-Goo;Zo, Moon-Shin;Jeon, Jong-Suh
    • Journal of Internet Computing and Services
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    • v.13 no.3
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    • pp.17-22
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    • 2012
  • In this paper, a photoelectric image detection system is proposed using an APD(Avalanche Photodiode) sensor, a LED illuminator, and fiberoptic waveguides. This proposed pinhole detection system can detect the pinholes of 100 micron with the speed rate of 1,000mpm(meter per minute). And detecting performance of image system is improved by the SQL based DB analysis of classifying pinhole's detected location and size using image detection algorithms.

Super-High-Speed Lightwave Demodulation using the Nonlinearities of an Avalanche Photodiode

  • Park, Young-Kyu
    • KIEE International Transactions on Electrophysics and Applications
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    • v.2C no.5
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    • pp.273-278
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    • 2002
  • Even though the modulating signal frequency of the light is too high to detect directly, the signal can be extracted by frequency conversion at the same time as the detection by means of the non-linearity of the APD. An analysis is presented for super-high-speed optical demodulation by an APD with electronic mixing. A normalized gain is defined to evaluate the performance of the frequency conversion demodulation. The nonlinear effect of the internal capacitance was included in the small signal circuit analysis. We showed theoretically and experimentally that the normalized gain is dependent on the down converted difference frequency component. In the experiment, the down converted different frequency outputs became larger than the directly detected original signal for the applied local signal of 20㏈m.

$K^{+}$ channel openers가 기니픽 심근의 수축력, 막전위 및 세포내 $Na^{+}$ 이온 활성도에 미치는 영향

  • 채수완
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 1992.05a
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    • pp.36-36
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    • 1992
  • 기니픽심장에서 유두근을 적출하여 valve 쪽은 silver wire에 연결하여 수축력을 측정하고 mural end는 sylgard floor에 pin으로 고정하여 1Hz로 자극하였다. 이때 사용된 영양액은 Tyrode Ringer로 bath내 은도는 36$^{\circ}C$이고 97% 0$_2$, 3% $CO_2$로 포화시켜 사용하였다. 수축력이 일정해진 후 막전위는 conventional electrode를 이용해서 기록하고, 세포내 $Na^{+}$ 이온 활성도( $a_{Na}$ $^{i}$ )는 $Na^{+}$ 선택적 전극을 이용해서 기록하였다. 적출 기니픽 심근에서 pinacidil, cromakalim, RP49356 둥의 $K^{+}$ channel opener는 활동전위 기간(APD)과 수축력 감소을 일으켰고, pinacidil과 cromakalim에 의한 APD 감소는 glibenclamide (10 $\mu$M)에 의해 거의 억제되었다. Pinacidil, RP49356 및 cromakalim에 의한 수축력 감소시 세포내 $Na^{+}$ 이온농도( $a_{Na}$ $^{i}$ )의 감소가 나타났으며 glibenclamide(10 $\mu$M)에 의한 APD의 감소는 거의 차단되었으나 $a_{Na}$ $^{i}$ 감소는 일부 나타났으며 이때 수축력의 감소도 나타났다.

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Development of a Program for Constructing Electromagnetic Noise Database (전파 잡음 데이터베이스 구축을 위한 프로그램 개발)

  • Yuk Jai-Lim;Hur Moon-Man;Yoon Hyun-Bo
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.15 no.9
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    • pp.856-862
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    • 2004
  • This paper introduces a program by which we can extract the optimal parameters from the statistical model, the amplitude probability distribution(APD), of the electromagnetic noise using genetic algorithm. The genetic algorithm used in this program has the advantages of the reduction of calculation time, the automation of extraction process, and the operation of global optimization.

Nanocatalyst Materials Prepared by Arc Plasma Deposition (아크플라즈마 증착을 이용한 나노촉매 재료 제작)

  • Kim, Sang Hoon
    • Applied Chemistry for Engineering
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    • v.25 no.4
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    • pp.341-345
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    • 2014
  • Catalyst nanoparticles are prepared by arc plasma deposition (APD). First, overview of the APD technique is reviewed and second, some applications of the technique for nanocatalyst preparation are reviewed. Nanoparticles prepared by APD are typically 1~5 nm in size and their catalytic activity is generally better than that of conventional wet-chemically prepared nanocatalysts.