• Title/Summary/Keyword: 가스감도

Search Result 163, Processing Time 0.027 seconds

Effect of Ultra-thin Catalyst Deposited upon $In_2O_3$ Thin Film on CO Sensitivity ($In_2O_3$ 박막위에 증착된 초박막 촉매가 CO의 검출 감도에 미치는 영향)

  • Lee, Hye-Jung;Song, Jae-Hoon;Kwon, Soon-Nam;Kim, Tae-Song;Kim, Kwang-Ju;Jung, Hyung-Jin;Choi, Won-Kook
    • Journal of Sensor Science and Technology
    • /
    • v.9 no.6
    • /
    • pp.430-439
    • /
    • 2000
  • $In_2O_3$-based thin film sensor with 500-600 nm thick was fabricated for the detection of CO gas by rf magnetron sputtering. In order to improve both sensitivity to CO gas and selectivity to hydrogen gas containing -CH, ultra-thin transition metal Co catalyst was sputtered over $In_2O_3$ thin film and annealed at $500^{\circ}C$. Sensitivity to CO was maximum at the thickness of Co 2.1 nm and $300^{\circ}C$, and that to $C_3H_8$ was at the thickness of Co 1.4 nm and $350-400^{\circ}C$. From the x-ray photoelectron spectroscopy (XPS) result, ultra-thin Co was existed into CoO covered with $Co_2O_3$ on $In_2O_3$ particles, and thus p-n junction of $In_2O_3(n-type)$-CoO(p-type) was thought to be formed. In this p-n junction type sensors, sensing mechanism with reducing gases can be explained by the variation of depletion layer thickness formed in the interface.

  • PDF

Estimation of Local Stress Change of Wall-Thinned Pipes due to Fluid Flow (유체유동에 의한 감육배관의 국부응력변화 평가)

  • Kim Young-Jin;Song Ki-Hun;Lee Sang-Min;Chang Yoon-Suk;Choi Jae-Boong
    • Journal of the Korean Institute of Gas
    • /
    • v.10 no.3 s.32
    • /
    • pp.7-12
    • /
    • 2006
  • In this paper, a new evaluation scheme is suggested to estimate load-carrying capacities of wall thinned pipes. At first, computational fluid dynamics analyses employing steady-state and incompressible flow are carried out to determine pressure distributions in accordance with conveying fluid. Then, the variational pressures are applied as input condition of structural finite element analyses to calculate local stresses at the deepest point. The efficiency of proposed scheme was proven from comparison to conventional analyses results and it is recommended to consider the fluid structure interaction effect for exact integrity evaluation.

  • PDF

Fabrication and NOx Sensing Characteristics of $WO_{3}$ Based Thick Film Devices Doped with $TiO_{2}$ and Noble Metals ($TiO_{2}$와 귀금속을 첨가한 $WO_{3}$ 후막 센서의 제조 및 NOx 감응 특성)

  • Lee, Dae-Sik;Han, Sang-Do;Son, Young-Mok;Lee, Duk-Dong
    • Journal of Sensor Science and Technology
    • /
    • v.6 no.4
    • /
    • pp.274-279
    • /
    • 1997
  • NOx sensors using tungsten oxide films as a base material were prepared and their electrical and sensing characteristics have been investigated. The $WO_{3}$ thick films doped with $SnO_{2}$ or $TiO_{2}$ showed higher sensitivity and better sorption characteristics to NOx gas than the pure $WO_{3}$ films material in air at operating temperature of $400^{\circ}C$. By addition of noble catalysts, such as Ru or Au, to the $TiO_{2}-WO_{3}$ thick films, their sensitivity, recovery and selectivity to NOx gas were found to be more enhanced.

  • PDF

Gas sensing properties of $LaFeO_3$ thin films fabricated by RF magnetron sputtering method (RF Magnetron Sputtering 법으로 제조된 $LaFeO_3$ 박막의 가스감지 특성)

  • Jang, Jae-Young;Ma, Dae-Young;Park, Ki-Cheol;Kim, Jeong-Gyoo
    • Journal of Sensor Science and Technology
    • /
    • v.9 no.5
    • /
    • pp.357-364
    • /
    • 2000
  • The structural, electrical and gas sensing characteristics of $LaFeO_3$ thin films fabricated by r.f. magnetron sputtering method on $Al_2O_3$ substrates were investigated. (121) domonant crystalline plane was observed for the films heat-treated at above $600^{\circ}C$ and gas sensing properties showed p-type semiconductor behaviors. Gas sensing characteristics of the $LaFeO_3$ thin films was studied as a function of film thicknesses and heat treatment temperatures. While the variation of the film thickness showed a little effect on the sensitivity, the heat treatment temperature was critical to the sensitivity. The thin films with thickness of 400 nm heat-treated at $800^{\circ}C$ showed the sensitivity of 400% for 5000ppm CO and 60% for 350ppm $NH_3$ at the working temperature of $300^{\circ}C$.

  • PDF

The Improvement of Sensitivity Characteristics of Pd doped $SnO_2$ Nanowire Gas Sensor (Pd 도핑에 따른 $SnO_2$ 나노선 가스센서의 감도 특성 개선)

  • Kim, Yeon-Woo;Kwon, Sun-Il;Park, Seung-Beom;Lee, Seok-Jin;Jung, Tae-Hwan;Yang, Kea-Joon;Lim, Dong-Gun;Park, Jae-Hwan;Kim, Hong-Oh
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2008.06a
    • /
    • pp.160-161
    • /
    • 2008
  • $SnO_2$는 n형 반도체로써 3.6 eV의 큰 밴드갭을 가지는 물질로 CO와 NOx 가스에 좋은 감도를 나타내는 것으로 보고되고 있다. 문헌에 따른 일반적인 $SnO_2$ 가스센서는 후막이나 벌크형태로 제작되었다. 근래에는 가스감응체가 $SnO_2$ 나노선 형태인 가스센서가 활발한 연구 중에 있다. 본 논문에서는 기판 위에 서로 분리된 전극 패턴에 Au를 촉매로 하여 네트워크 구조로 된 $SnO_2$ 나노선이 합성되었다. 제작된 가스센서에 Pd 도핑에 따른 영향을 알아보기 위하여 1.8 mM의 Pd 용액 ($PdCl_2{\cdot}xH_2O$ 3 mg + $H_2O$ 10 ml)을 이용하여 센서에 도핑하였다. 측정 시스템에서 $NO_2$ 가스에 대한 센서의 특성을 분석한 결과 도핑하지 않은 $SnO_2$ 센서보다 20%정도의 감도가 개선되었다.

  • PDF

Fabrication and Characteristics of ZnO/In Micro-sensor for detecting $NH_3$ gas ($NH_3$ 가스 감지용 ZnO/In 마이크로센서의 제작 및 특성)

  • Kim, Gwon-Tae;Lee, Yong-Sung;Kim, Dae-Hyun;Park, Hyo-Derk;Jeon, Choon-Bae;Ma, Tae-Young;Park, Ki-Cheol
    • Proceedings of the KIEE Conference
    • /
    • 2000.07c
    • /
    • pp.2251-2253
    • /
    • 2000
  • MEMS기술을 이용하여 단층 실리콘 나이트라이드($Si_{3}N_4$) 다이아프램을 제조하고, 이 다이아프램상에 저항성 가열 진공증착법과 고주파 마그네트론 스퍼터링법을 이용하여 차례로 In막과 ZnO막을 증착하고, In의 도핑을 위해 열처리하여 $NH_3$ 가스 감지용 마이크로센서를 제작하였다. 감지막의 열처리온도에 따른 구조적 및 전기적 특성은 XRD, SEM, AFM, 4-point probe 및 Electrometer를 통하여 각각 조사하였다. 제작된 센서의 열처리온도와 인가전력에 따라 $NH_3$ 가스에 대한 감도, 선택성 및 시간응답 특성을 조사하였다. 감지막 두께 3000 ${\AA}$, 열처리온도 400$^{\circ}C$로 제조된 마이크로 센서가 히터 인가전력 366 mW에서 100 ppm의 $NH_3$ 가스농도에서 대하여 16 %, 350 ppm의 가스농도에서 대하여 23 %의 가장 우수한 감도를 나타내었다. 그러나 CO 가스 및 $NO_x$ 가스에 대한 감지특성은 관찰되지 않았다.

  • PDF

The Hall Measurement and TMA Gas Detection of ZnO-based Thin Film Sensors (ZnO 박막 센서의 TMA 가스 및 Hall 효과 측정)

  • Ryu, Jee-Youl;Park, Sung-Hyun;Choi, Hyek-Hwan;Lee, Myong-Kyo;Kwon, Tae-Ha
    • Journal of Sensor Science and Technology
    • /
    • v.6 no.4
    • /
    • pp.265-273
    • /
    • 1997
  • The TMA gas sensors are fabricated with the ZnO-based thin films grown by a RF magnetron sputtering method. We investigate the surface carrier concentration, Hall electron mobility, electrical resistivity and sensitivity according to temperature variation and TMA gas concentration. The ZnO-based thin film sensors prepared by sputtering in oxygen showed higher surface carrier concentration, higher Hall mobility, higher sensitivity, and lower electrical resistivity than sensors prepared by sputtering in argon. The doping ZnO-based thin film sensors showed the same electrical properties in comparison with nondoping sensors. In case of sputtering on the oxygen gaseous atmosphere, the ZnO-based thin film sensors doped with 4.0 wt.% $Al_{2}O_{3}$, 1.0 wt.% $TiO_{2}$, and 0.2 wt.% $V_{2}O_{3}$ showed the highest surface carrier concentration of $5.95{\times}10^{20}cm^{-3}$, Hall electron mobility of $177\;cm^{2}/V{\cdot}s$, lowest electrical resistivity of $0.59{\times}10^{-4}{\Omega}{\cdot}cm$ and highest sensitivity of 12.1(working temperature, $300^{\circ}C$, TMA gas, 8 ppm).

  • PDF

Gas sensing characteristics of $TiO_{2}/WO_{3}$ thick film for hydrocarbon gas (후막형 $TiO_{2}/WO_{3}$ 소자의 탄화수소계가스에 대한 감도 특성)

  • Chang, Dong-Hyuck;Choi, Dong-Han
    • Journal of Sensor Science and Technology
    • /
    • v.5 no.2
    • /
    • pp.21-27
    • /
    • 1996
  • Thick film $TiO_{2}/WO_{3}$ butane gas sensors were fabricated by the screen printing method and their gas sensing characteristics were investigated. The sensitivity of $TiO_{2}/WO_{3}$ thick film was higher than that of pure $WO_{3}$ film to butane. The $WO_{3}$ film with 2wt.% $TiO_{2}$ showed the highest sensitivity to butane. And the optimum heat treatment temperature was $650^{\circ}C$. That film showed the highest sensitivity to butane at the operating temperature of $350^{\circ}C$. The sensitivity of the film to 20000ppm butane in air was 80% at the operating temperature of $350^{\circ}C$.

  • PDF

A Study on Micro Gas Sensor Utilizing WO$_3$ Thin Films Fabricated by Sputtering Method (스퍼터링법으로 제작한 WO$_3$ 박막을 이용한 NO$_2$ 마이크로 가스센서에 관한 연구)

  • 김창교;이영환;노일호;유홍진;유광수;기창진
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.4 no.3
    • /
    • pp.139-144
    • /
    • 2003
  • A flat type micro gas sensor was fabricated on the p-type silicon wafer with low stress Si$_3$N$_4$, whose thickness is 2 ${\mu}{\textrm}{m}$, using MEMS technology. WO$_3$ thin film as a sensing material for detection of NO$_2$ gas was deposited using a tungsten target by sputtering method, followed by thermal oxidation at several temperatures (40$0^{\circ}C$-$600^{\circ}C$) for one hour. NO$_2$ sensitivities were investigated for the WO$_3$ thin films with different annealing temperatures. The highest sensitivity was obtained for the samples annealed at $600^{\circ}C$ when it was operated at 20$0^{\circ}C$. The results of XRD analysis showed the annealed samples had polycrystalline phase mixed with triclinic and orthorhombic structures. The sample exhibits higher sensitivity when the system has less triclinic structure. The sensitivities, $R_{gas}/R_{air},$ operating at 20$0^{\circ}C$ to 5 ppm NO$_2$ of the sample annealed at $600^{\circ}C$ were approximately 90.

  • PDF

At the crossroads: An uncertain future facing the electricity-generation sector in South Korea (월드 리포트 - 대한민국 발전산업의 불확실한 미래)

  • Hong, Sanghyun;Brook, Barry W.
    • Nuclear industry
    • /
    • v.38 no.6
    • /
    • pp.21-32
    • /
    • 2018
  • 원자력 발전은 지난 수십 년 동안 대한민국에서 가장 중요하고 청정한 전기 에너지 공급원 역할을 감당해왔다. 그렇지만 한국 정부는 원자력 발전의 점유율을 줄이고 재생에너지의 비중을 높이는 것을 목표로 하는 에너지 전환 정책 로드맵을 발표하였다. 그러나 한국의 높은 인구밀도를 놓고 볼 때, 전력 생산의 최대 에너지원을 재생에너지로 전환하겠다는 구상은 무리일 수밖에 없다. 그 이유는 재생에너지 발전량만으로는 다 감당할 수 없는 원자력 발전량의 감축 부분을 어떻게 보충하겠다는 언급이 한국 정부의 로드맵에는 없기 때문이다. 암묵적으로 받아들여지고 있는 대안은 결국 화석연료인 것 같은데, 한국정부가 어떤 화석연료를 선택하느냐 하는 문제는 온실가스 배출량 감축이라는 문제와 직결되므로 그것이 최종 결정의 핵심적 요소가 될 것이다. 우리는 시나리오 분석 방법을 통해 한 가지 재생에너지를 선택한다는 가정과 함께 두 종류의 화석연료를 주로 사용하게 되는 경우를 분석해 보았다. 아울러 우리는 다른 나라들의 세 가지 에너지계획과 비교 분석한 사항을 바탕으로 원자력 에너지 외에 한국 정부가 선택할만한 에너지원의 타당성과 각 에너지 별 선택에 따른 제약사항을 밝히면서 최악의 결과를 방지하기 위한 기술-경제상의 필수적인 조건들을 제안하려 한다.

  • PDF