http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
- 검색키워드
- 저자 : 전재목 (검색결과 4 건)
-
-
SnO2/WO3를 기반으로 한 Acetaldehyde 검출용 Gas sensor
This study investigated sensitivity of the gas sensor to acetaldehyde with the various operating temperatures and catalysts. The nano-sized WO₃ powder mixed with metal oxide(SnO2) were doped with transition metals(Pt, Ru, Pd and In). WO₃ and SnO₂ nano-sized powder were prepared by sol-gel and chemical precipitation method. The physical and chemical properties of these films were investigated by SEM/EDS, XRD and BET analyses. The metal-WO₃ thick films were prepared by screen-printing method onto Al2O3 substrates with platinum electrode. The sensing characteristics were investigated by measuring the electrical resistance of each sensor in a test box as a function of detection gas concentration. This was then used to detect acetaldehyde and various VOCs gases within a concentration range of 20∼100 ppm. The measured sensitivity to VOCs gas is defined as the ratio (Ra/Rg) of the resistance(Rair) of WO₃ film in air to the resistance(Rgas) of WO₃ film in a VOCs test gas. The sensitivity and selectivity of these films were tested to the various VOCs such as acetaldehyde, formaldehyde, methylalcohol and BTEX(Benzene, Toluene, Ethyl benzene and Xylene). The WO₃ thick film with 1wt.% Ru, 5wt.% SnO₂ showed the best sensitivity and selectivity for acetaldehyde gas at the operating temperature of 300℃. 본 연구에서는 주물질인 WO₃에 금속산화물과 촉매의 첨가에 따른 아세트알데히드 가스를 검출하기 위한 가스센서에 대해 연구하였다. 전기적 안정성을 위해 금속산화물(SnO₂)을 첨가한 WO₃ 나노분말에 선택성 및 감도향상을 위해 함침법으로 다양한 금속촉매(Pt, Ru, Pd and In)를 첨가하였다. WO₃와 SnO₂ 나노 분말은 각각 졸겔법과 수산화물 침전법을 이용하여 제조하였고 SEM/EDS, XRD, BET analyzer를 이용하여 제조된 분말의 물리, 화학적 특성을 조사하였다. SnO₂/WO₃ 후막필름은 Pt전극이 형성되어 있는 알루미나 지지체 위에 스크린프린팅법을 이용하여 도포하였다. 가스센서의 감도 특성은 검출가스농도의 함수로서 챔버 내 각 센서물질별 전기적 저항 변화를 측정하였고, 20∼100 ppm의 농도범위에서 아세트알데히드와 다양한 VOCs 가스에 대해서 감도 특성을 조사하였다. 센서의 감도는 공기 중에서의 전기저항값(Ra)에 대한 감지가스주입 후 전기저항값(Rg)의 비로 정의하였다. 센서의 감도, 선택성, 반응회복특성 연구는 acetaldehyde, formaldehyde, methyl alcohol and BTEX(Benzene, Toluene, Ethyl benzene, Xylene)과 같은 다양한 VOCs gas에 대해서 조사하였다. Acetaldehyde gas를 검지하기 위한 센서물질의 최적 상태는 소성온도 500℃, 작동온도 300℃, 후막두께 20㎛, 바인더로서 ethylene glycol, 구성으로는 WO₃에 5wt.% SnO₂와 1wt.% Ru를 첨가하였을 경우 가장 최적의 감도, 선택성 그리고 반응회복 특성을 보였다.
-
A Study on the Cutting Mechanism of the Glasses for Flat Panel Display Jea-Mok Jeon Department of Mechanical Engineering, Graduate School Kum-oh National Institute of Technology Abstract Modern IT industry ignites lots of researches in high technology oriented displays such as CRT, LCD, PDP, ELD, VPD and LED. The trend, therefore, requires researches on the techniques of cutting the flat panels from various manufacturing processes effectively. In this study the method of diamond wheel scribing was selected for cutting the panels, and the vibrations were applied on the cutting tool head. The quality of the cut surfaces was inspected with the variations of cutting conditions such as additional scribing pressure, frequency, applied electric charge and the application methods of vibrations. Fracture behavior of the cut surface was studied with the vibration applications. The effect of the vibrations on the crack propagation was investigated by applying the cutting mechanism without the breaking process, and also the factors for the best cutting condition were analyzed. The result shows that the increase in wheel force causes the same trend in depth of scribe and the vertical crack length, and that the force bigger than 2.5kgf secures the full-cutting in almost all circumstances.
-
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
