Search results for "Volta"
showing 10 items of 2055 documents
Channel flow at an immobilised liquid|liquid interface
2000
A novel rectangular channel flow electrochemical cell for the study of liquid | liquid interfaces is presented. The organic phase is immobilised by the use of a gelling agent, while the aqueous phase flows past the interface. This creates an asymmetric setup that allows us to establish diagnostic criteria to determine, for example, the direction of the ion transfer. The effects of varying flow rate and sweep rate have been considered both theoretically and experimentally. By comparison with two-dimensional simulations, it is demonstrated that a simple one-dimensional theory can be used to describe the cyclic voltammetry response of the channel flow cell.
Ion-exchange voltammetry at a surfactant-doped electrode: model of mass transfer kinetics to an anionic surface-charged electrode and its application…
2000
cited By 10; International audience; A theoretical model of mass transfer kinetics was developed for investigating the accumulation of cationic compounds at an anionic surfactant-doped screen-printed electrode. It was extended to an enzyme-generated cationic product for the indirect determination of alkaline phosphatase (AP). The model takes into account the analyte depletion, the kinetics of the ion-exchange reaction-diffusion and the kinetics of the enzymatic reaction. The relationship between the ion-exchange voltammetric anodic peak current and the enzyme incubation/accumulation time for a given concentration of AP was established and the validity of the theoretical model was verified e…
Electrochemistry-based chemotaxonomy in plants using the voltammetry of microparticles methodology
2015
A methodology for characterizing vegetal taxonomic groups using microextraction-assisted voltammetry of microparticles is described. It is based on recording the voltammetric response of microparticulate films of polyphenolic compounds of leaf extracts using different organic solvents. As a result, characteristic voltammetric profiles, tentatively defining an electrochemolomic response, are obtained. Bivariant and multivariant chemometric evaluation of the voltammetric responses of such films allows characterizing vegetal families. Analysis of voltammetric responses for a set of species of the Rosales order suggests that electrochemical data can be correlated with phylogenetic trees.
Reduction of ferricytochrome c catalyzed by optically active chromium(III) complexes
2009
The reduction rates of horse heart ferricytochrome c by amalgamated zinc or by electrolysis at fixed potential on a mercury pool as the cathode have been measured in a buffered solution at pH 7.5 by absorption spectrophotometry. In both cases, the reaction was strongly accelerated by the presence of the optically active complexes Lambda-[Cr(III)((S,S)-promp)H(2)O](+) (H(2)promp = N,N'-[(pyridine-2,6-diyl)bis(methylene)]-bis[(S)-proline]), Delta-[Cr(III)((R,R)-alamp)H(2)O](+) (H(2)alamp = N,N'-[(pyridine-2,6-diyl)bis(methylene)]-bis[(R)-alanine]) and Lambda-[Cr(III)((S,S)-alamp)(H(2)O)(2)](+). These were shown to undergo reversible one-electron reduction to the corresponding labile chromium(…
Spectroscopic and electrochemical study of interactions between DNA and different salts of 1,4-dihydropyridine AV-153
2020
1,4-dihydropyridines (1,4-DHP) possess important biochemical and pharmacological properties, including antimutagenic and DNA-binding activity. The latter activity was first described for water-soluble 1,4-DHP with carboxylic group in position 4, the sodium salt of the 1,4-DHP derivative AV-153 among others. Some data show the modification of physicochemical properties and biological activities of organic compounds by metal ions that form the salts. We demonstrated the different affinity to DNA and DNA-protecting capacity of AV-153 salts, depending on the salt-forming ion (Na, K, Li, Rb, Ca, Mg). This study aimed to use different approaches to collate data on the DNA-binding mode of AV-153-N…
Thalamic Network Oscillations Synchronize Ontogenetic Columns in the Newborn Rat Barrel Cortex
2013
Neocortical areas are organized in columns, which form the basic structural and functional modules of intracortical information processing. Using voltage-sensitive dye imaging and simultaneous multi-channel extracellular recordings in the barrel cortex of newborn rats in vivo, we found that spontaneously occurring and whisker stimulation-induced gamma bursts followed by longer lasting spindle bursts were topographically organized in functional cortical columns already at the day of birth. Gamma bursts synchronized a cortical network of 300-400 µm in diameter and were coherent with gamma activity recorded simultaneously in the thalamic ventral posterior medial (VPM) nucleus. Cortical gamma b…
Synthesis, photochemistry, and electrochemistry of (P)Ge(R)2 and (P)Ge(R)X (P = TPP or OEP, R = CH3, CH2C6H5, or C6H5, and X = Cl-, OH-, or ClO4-)
1987
Chaque complexe est caracterise par spectroscopie RMN de H1, UV-visible, IR et aussi par l'etude electrochimique
DAQs-based wattmeters for high accuracy measurements. Comparison with the Italian power primary standard
2013
Abstract This paper is focused on the use of data acquisition boards (DAQs) for the development of high accuracy PC-based instruments for the measurements of electrical power. The proposed systems are simple, portable and low cost because they are based on commercial data acquisition boards (DAQs) connected to a common personal computer. Data processing is carried out by a commercial software based on an interpolating windowed FFT. In the paper it is shown how the voltage can be sensed directly, thanks to the DAQ input range, thus avoiding expensive voltage dividers. The set up of the DAQs-based solutions is described and the evaluation of their metrological features is made by means of a c…
High Frequency Model of PV Systems for the Evaluation of Ground Currents
2012
A high frequency model of a photovoltaic (PV) plant is developed and analysed to investigate the common mode (CM) currents circulating through the ground connections of the plant. The modelling method is based on the measurement of the impedance frequency response of photovoltaic module and on a high frequency representation of the power conversion unit. An overall lumped parameters circuit model is obtained and then implemented in PSpice. The CM leakage currents are evaluated by simulation.
Evaluation of ground currents in a PV system with high frequency modeling
2018
In this work a high frequency model of a photovoltaic (PV) plant is identified and implemented aiming to investigate the common mode (CM) currents circulating through the ground connections of the plant. From the identification of the impedance obtained by frequency response of photovoltaic module and by a suitable of the power conversion unit, an equivalent high frequency circuit representation has been developed. The lumped parameters circuit model is implemented in PSpice environment to obtain the CM leakage currents. Harmonics at frequencies multiple of the switching frequency and a strong resonance at about 12 MHz are detected.