• 제목/요약/키워드: Chemical Detection

검색결과 1,715건 처리시간 0.03초

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

  • Li, Liping;Tang, Ju;Liu, Yilu
    • Journal of Electrical Engineering and Technology
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    • 제10권4호
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    • pp.1765-1772
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    • 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
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    • 제31권11호
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    • pp.3159-3162
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    • 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.

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

  • 이미순
    • 한국식품과학회지
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    • 제11권3호
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    • pp.166-170
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    • 1979
  • UVSL-25 mineral light를 조사(照射)한 경우에 발생하는 식품(食品) 보존료(保存料) 자체(自體)의 형광(螢光)을 이용하여 신속하고 간편하게 보존료(保存料)를 검사(檢査)할 수 있는 방법(方法)을 시도(試圖)하였다. 유동(流動) 파라핀에 현탁(懸濁)된 분말(粉末) 시료(試料)의 흡수(吸收) 및 발광(發光) 스펙트럼은 보존료(保存料)의 종류에 따라 특징적인 패턴을 나타냈다. 장파장(長波長) 측(側) 및 단파장(短波長) 측(側) 영역(領域)의 자외선(紫外線) 조사(照射)에서 얻은 스펙트럼 특성을 대조(對照)하여 비교하므로써 보존료(保存料)의 종류가 보다 용이하게 판별되었다.

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

  • 이은주;등도소;박수길
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2002년도 추계학술대회 논문집 전기물성,응용부문
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    • pp.167-169
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    • 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.

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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
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    • 제36권6호
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    • pp.975-980
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    • 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.