Open Circuit (open + circuit)

Distribution by Scientific Domains

Terms modified by Open Circuit

  • open circuit potential
  • open circuit voltage

  • Selected Abstracts

    Calixarene/Nafion-Modified Bismuth-Film Electrodes for Adsorptive Stripping Voltammetric Determination of Lead

    ELECTROANALYSIS, Issue 17-18 2009
    Ferenc Torma
    Abstract This paper presents an enhanced adsorptive stripping voltammetric procedure (AdSV) for the determination of Pb2+, which relies on the accumulation of the metals at a calixarene-based chemically modified bismuth-film electrode on glassy carbon substrate. Following the accumulation of the target metals at open circuit and a medium exchange, both the square wave anodic stripping detection of the metal ions and the in situ bismuth-film formation was performed simultaneously in a Bi3+ containing supporting electrolyte. The analysis of Pb2+ under optimized conditions resulted in stripping responses with good linearity (in the range 0.05,0.6,,M) and precision (RSD=1.12% at 0.2,,M Pb2+; n=10) and low detection limit (0.02,,g/L at 10,min preconcentration). The determination of Pb2+ (0.4,,M) at 100-fold excess of interfering ions (Cd2+, Cu2+ and Zn2+) yielded well resolved lead signal. The analytical utility of the method elaborated was tested in the analysis of trace Pb2+ in environmental water samples. [source]

    Preparation, Characterization and Analytical Applications of a New and Novel Electrically Conducting Polymer

    ELECTROANALYSIS, Issue 15 2006
    F. D'Eramo
    Abstract In this study, a glassy carbon electrode (GC) was modified with an electropolymerized film of 1-naphthylamine (1-NAP) with a subsequent overoxidation treatment in 0.2,M sodium hydroxide solution. This polymer p-1-NAPox film coated GC electrode was used for the selective determination of dopamine (DA) in the presence of a triple concentration of ascorbic acid (AA). These studies were performed using cyclic voltammetry and square-wave voltammetry at physiological pH. p-1-NAPox shows an attractive permselectivity, a marked enhancement of the current response and antifouling properties when compared to a bare GC electrode activated in basic media. With a preconcentration time of 3,minutes at open circuit, linear calibration plots were obtained for DA in buffer solution (pH,7.4) over the concentration range from 110,6,110,4 M with a detection limit of 1.5910,7 M. [source]

    Application of a Carbon Paste Electrode Modified with a Schiff Base Ligand to Mercury Speciation in Water

    ELECTROANALYSIS, Issue 11 2005
    Montserrat Colilla
    Abstract A carbon paste electrode, modified with benzylbisthiosemicarbazone is used for mercury speciation in water samples. Mercury ion is selectively accumulated on the electrode surface at open circuit and its analysis was performed by cyclic voltammetry or square-wave voltammetry (SWV). A detection limit of 8,,g L,1 (3,) was found for 15,min of accumulation using SWV as measurement technique. The effect of several metallic ions and organic substances on voltammetric signal is examined. For speciation purposes, a ligand competition methodology between ligands in solution and electrode is used. Model mercury complexes are characterized as a function of their dissociation kinetics. The method was applied to mercury speciation in water samples from the Jarama River in Madrid. [source]

    Adsorptive Stripping Voltammetric Detection of Single-Stranded DNA at Electrochemically Modified Glassy Carbon Electrode

    ELECTROANALYSIS, Issue 23 2002
    Huai-Sheng Wang
    Abstract Electrochemically modified glassy carbon electrode (GCE) was used to study the electrochemical oxidation and detection of denatured single-stranded (ss) DNA by means of adsorptive stripping voltammetry. The modification of GCE, by electrochemical oxidation at +1.75,V (vs.SCE) for 10,min and cyclic sweep between +0.3,V and ,1.3,V for 20,cycles in pH,5.0 phosphate buffer, results in 100-fold improvement in sensitivity for ssDNA detection. We speculated that the modified GCE has a high affinity to single-stranded DNA through hydrogen bond (specific static adsorption). Single-stranded DNA can accumulate at the GCE surface at open circuit and produce a well-defined oxidation peak corresponding to the guanine residues at about +0.80,V in pH,5.0 phosphate buffer, while the native DNA gives no signal under the same condition. The peak currents are proportional to the ssDNA concentration in the range of 0,18.0,,g,mL,1. The detection limit of denatured ssDNA is ca. 0.2,,g mL,1 when the accumulation time is 8,min at open circuit. The accumulation mechanism of ssDNA on the modified GCE was discussed. [source]

    Optimization of output matching network for class F power amplifier according to envelope in the envelope elimination and restoration transmitter

    Chongmin Lee
    Abstract This article presents the design and optimization of output matching network according to envelope for class F power amplifier (PA), which is to apply to envelope elimination and restoration (EER) transmitter. In this article, to increase the PAE of class F PA, which applies to EER transmitter, the varactor diode has been used on output matching network. As envelope changes, it optimizes constitution of harmonic trap that is short circuit in second-harmonic and is open circuit in third-harmonic. When drain voltage changes from 25 V to 30 V, some percentage is improved in the PAE. 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1890,1893, 2010; Published online in Wiley InterScience ( DOI 10.1002/mop.25335 [source]

    Classification of semiconductor defects using a small number of training data and qualitative knowledge

    Shohei Shimomura
    Abstract In semiconductor wafer manufacturing processes, defect candidates are usually extracted by an inspection system. The defect candidates are composed of true defects such as open circuits, contaminants, and bridges, as well as nondefect patterns, called nuisances, which predominate over true defects. The goal of this study is to classify the defect candidates as the various true defects and nuisances by using a small number of training data obtained by SEM inspection. It is shown that the accuracy of clustering is considerably improved by use of qualitative knowledge about the defects, given a priori by inspectors, in the clustering processes. 2009 Wiley Periodicals, Inc. Electron Comm Jpn, 91(11): 46,54, 2008; Published online in Wiley InterScience ( DOI 10.1002/ecj.10183 [source]