• Title/Summary/Keyword: Chemical Detection

Search Result 1,715, Processing Time 0.026 seconds

Application of Joint Electro-Chemical Detection for Gas Insulated Switchgear Fault Diagnosis

  • Li, Liping;Tang, Ju;Liu, Yilu
    • Journal of Electrical Engineering and Technology
    • /
    • v.10 no.4
    • /
    • pp.1765-1772
    • /
    • 2015
  • The integrity of the gas insulated switchgear (GIS) is vital to the safety of an entire power grid. However, there are some limitations on the techniques of detecting and diagnosing partial discharge (PD) induced by insulation defects in GIS. This paper proposes a joint electro-chemical detection method to resolve the problems of incomplete PD data source and also investigates a new unique fault diagnosis method to enhance the reliability of data processing. By employing ultra-high frequency method for online monitoring and the chemical method for detecting SF6 decomposition offline, the acquired data can form a more complete interpretation of PD signals. By utilizing DS evidence theory, the diagnostic results with tests on the four typical defects show the validity of the new fault diagnosis system. With higher accuracy and lower computation cost, the present research provides a promising way to make a more accurate decision in practical application.

A New Chemosensing Ensemble for Colorimetric Detection of Oxalate in Water

  • Tang, Li-Jun;Liu, Ming-Hui
    • Bulletin of the Korean Chemical Society
    • /
    • v.31 no.11
    • /
    • pp.3159-3162
    • /
    • 2010
  • To realize highly selective recognition of oxalate in water, a new chemosensing ensemble that behaves highly selective colorimetric recognition of oxalate in water at pH 7.4 has been developed. The ensemble was constructed by a pyrrole containing mononuclear copper complex and chromeazurol S. The ensemble shows a highly selective recognition of oxalate through an obvious color change from blue to yellow upon the addition of oxalate, whereas, other dicarboxylates such as malonate, succinate, fumarate, maleate, glutarate, adipate, phthalate, isophthalate and terephthalate do not induce any noticeable color changes. The oxalate recognition process is not significantly affected by other coexisting dicarboxylate.

Detection of Chemical Preservatives by the Use of Fluorescence (형광(螢光)을 이용한 식품(食品) 방부제의 검사(檢査))

  • Lee, Mie-Soon
    • Korean Journal of Food Science and Technology
    • /
    • v.11 no.3
    • /
    • pp.166-170
    • /
    • 1979
  • A rapid and simple method for detecting chemical preservatives was attempted on the basis of emitted fluorescence at the illumination of UVSL-25 mineral light. Absorption and fluorescence spectra of powdered samples dispersed in liquid paraffin revealed characteristic patterns depending on chemical preservatives. Detection of chemical preservatives was more readily accomplished by simultaneous comparison of spectral characteristics at long and short wave ranges of the exciting light.

  • PDF

Detection of Bio-chemical by Boron-doped Diamond Electrode (붕소가 도핑된 다이아몬드 전극을 이용한 생체화학물질의 검출)

  • Lee, Eun-Ju;Fujishima, A.;Park, Soo-Gil
    • Proceedings of the KIEE Conference
    • /
    • 2002.11a
    • /
    • pp.167-169
    • /
    • 2002
  • Selective, highly stable determination of serotonin was achieved in cyclic voltammetric measurement carried out at electrochemically treated conductive boron-doped diamond electrode. Boron-doped diamond electrodes were prepared on single crystal Si wafers by microwave plasma chemical vapor deposition and $B_2O_3$ was dissolved in acetone/methanol(9:1) mixture solution so that the B/C weight ratio ca. $10^4ppm$. Serotonin is a kind of indoleamines, which secreted from adrenal marrow cells. The serious problem to detection of serotonin is the interference phenomena of electroactive constituent, including AA. In this study, electrochemical treatment of HDD was carried out to discriminate between serotonin and AA responses. Experimental results showed that the peak potential of AA oxidation shift to the positive direction and the oxidation peak of serotonin was unchanged.

  • PDF

Surface-enhanced infrared detection of benzene in air using a porous metal-organic-frameworks film

  • Kim, Raekyung;Jee, Seohyeon;Ryu, Unjin;Lee, Hyeon Shin;Kim, Se Yun;Choi, Kyung Min
    • Korean Journal of Chemical Engineering
    • /
    • v.36 no.6
    • /
    • pp.975-980
    • /
    • 2019
  • Infrared (IR) spectroscopy is a powerful technique for observing organic molecules, as it combines sensitive vibrational excitations with a non-destructive probe. However, gaseous volatile compounds in the air are challenging to detect, as they are not easy to immobilize in a sensing device and give enough signal by themselves. In this study, we fabricated a thin nanocrystalline metal-organic framework (nMOF) film on a surface plasmon resonance (SPR) substrate to enhance the IR vibration signal of the gaseous volatile compounds captured within the nMOF pores. Specifically, we synthesized nanocrystalline HKUST-1 (nHKUST-1) particles of ca. 80 nm diameter and used a colloidal dispersion of these particles to fabricate nHKUST-1 films by a spin-coating process. After finding that benzene was readily adsorbed onto nHKUST-1, an nHKUST-1 film deposited on a plasmonic Au substrate was successfully applied to the IR detection of gaseous benzene in air using surface-enhanced IR spectroscopy.