• Title/Summary/Keyword: Oder Sensor

Search Result 14, Processing Time 0.017 seconds

Fabrication and Characteristics of ZnO-based thin film sensors with high selectivity for TMA gas (TMA 가스 선택성 향상을 위한 ZnO계 박막센서의 제작 및 특성)

  • Park, Sung-Hyun;Choi, Woo-Chang;Kim, Sung-Woo;Ryu, Jee-Youl;Choi, Hyek-Hwan;Lee, Myong-Kyo;Kwon, Tae-Ha
    • Journal of Sensor Science and Technology
    • /
    • v.9 no.1
    • /
    • pp.36-43
    • /
    • 2000
  • In oder to enhance the selectivity of TMA(trimethylamine) gas, the ZnO-based films which were doped with $Al_2O_3$, $TiO_2, $In_2O_3$ and $V_2O_5$ catalysts with various weight percents were deposited in oxygen by RF magnetron sputtering method. To improve electrical stability of sensors, the ZnO-based films were annealed in oxygen at $700^{\circ}C$ for 1 hour. The TMA selectivity of sensors was defined by the magnitude($S_{TMA}/S_{DMA}$ and $S_{TMA}/S_{NH3}$) of TMA sensitivity relative to DMA and sensitivity ammonia($NH_3$) sensitivity, respectively. The $ZnO+Al_2O_3(4\;wt.%)+TiO_2(1\;wt.%)+In_2O_3(1\;wt.%)$ sensor showed high $S_{TMA}/S_{DMA}$ of 5.9 and $S_{TMA}/S_{NH3}$ of 26 to 160 ppm at the working temperature of $300^{\circ}C$ respectively.

  • PDF

Analysis on the Noise Factors of Static Induction Photo-Transistor (SIPT) (1) - The SIPT's Equivalent Circuits for the Analysis on the Noise Factors - (정전유도(靜電誘導) 포토 트랜지스터의 잡음(雜音) 원인(原因) 분석(分析) (1) - 잡음(雜音) 원인(原因) 분석(分析)을 위한 SIPT 등가회로(等價回路) -)

  • Kim, Jong-Hwa
    • Journal of Sensor Science and Technology
    • /
    • v.4 no.4
    • /
    • pp.29-40
    • /
    • 1995
  • In this paper, the noise equivalent cicuits that is necessary to the formulation of D.C. and noise characteristics, residual component and input capacitance so as to analyze on the noise factors of the SIT is proposed. The simplest noise equivalent circuit is the model representing the mechanism of the SIT and the measured values in this model were found as small as the values of the shot-noise. In the source resistance inserted equivalent circuit is conformed that the shot-noise will be reduced by the negative-feedback effect of the source resistance. In oder to analyze the correct noise reduction factor, I proposed the equivalent circuit which the formulas of the source and drain resistance was induced. In the experiment which affirm the equivalent circuits, the influence of the signal source resistance and output load resistance on the residual component is small and the residual component can be expressed by the equivalent input noise resistance. Moreover, the input capacitance is 13.6 pF when the load resistance is $0{\Omega}$ and the capacitance which does not concern with the SIT operation directly, that is, gate wire etc, is 10pF or so.

  • PDF

Development of Anti-disaster System for Natural Gas Governor Station Using Wire and/or Wireless Communication ($\cdot$무선 데이터 통신을 이용한 천연가스 정압소의 안전방재 시스템 개발)

  • Yoo Hui Ryong;Park Dae Jin;Koo Sung Ja;Park Seoung Soo;Rho Yong Woo
    • Journal of the Korean Institute of Gas
    • /
    • v.3 no.2 s.7
    • /
    • pp.17-23
    • /
    • 1999
  • The wire and/or wireless data communication system for anti-disaster system of natural gas governor station was developed. In oder to prevent accidents of governor station, the operator was replaced by RTU(Remote Terminal Unit) which gather and transmit safety situation of governor station. The database and MMI(Man Machine Interface) were also developed to analyze the situation of governor station. The data communication between server and RTU was designed to switch automatically from wire to wireless communication and vice versa when one of them failed communication. We also have developed the patrol car management system which was applied GPS(Global Position System)/GIS(Geometric Information System), and the earthquake detection/transmission system which was adopted three dimension acceleration sensor. When a earthquake may occur, the earthquake detection/transmission system monitors data such as PGA(Peak Ground Acceleration), Sl(Spectrum Intensity) and orders the emergency shutoff valve close immediately.

  • PDF

Measuring the Environment of Pig Houses (돈사의 환경계측에 관한 연구)

  • 최규홍;손재룡;이강진;최동수;최용삼;남상일
    • Journal of Animal Environmental Science
    • /
    • v.7 no.3
    • /
    • pp.155-164
    • /
    • 2001
  • Environmental factors such as $NH_3,\;H_2S,\;CO_2$, dust, temperature, and humidity in the animal house are a potential health hazard to humans and animals. Until now, most of measurement methods can only provide periodic results with low accuracy. A data acquisition system which can measure continuously and simultaneously $NH_3,\;H_2S,\;CO_2$, temperature, and humidity was developed and installed in two pig houses. Daily changes of environment for the pig-houses were investigated by the data acquisition system. In order to evaluate NH$_3$sensor, gas samples were obtained and NH$_3$concentrations were measured at nine positions; combinations of three positions(inlet, middle, and outlet) and three heights(0 cm, 40 cm, 150 cm). Ammonia concentration of 14.0 ~37.1 ppm for slurry pig-house is higher than that of 8.4~29.7 ppm for scraper pig-house, and there were no statistical differences among the positions. However, the concentration of $NH_3$at 150 cm was higher than thats of 0 cm and 40 cm.

  • PDF