In Situ Monitoring of Generation and Precipitation of Ferric Hydroxide Sol with a Piezoelectric Quartz Crystal Impedance Analyzer

Electrochemical quartz crystal microbalance study on growth and property of the polymer deposit at gold electrodes during oxidation of dopamine in aqueous solutions

“…A conventional oscillation-circuit/frequency-counter routine was first employed for EQCM construction due mainly to its simplicity and cost effectiveness [8], however, generally the piezoelectric information only on the oscillating frequency can be acquired. Later, the more sophisticated impedance-/network-analysis method has also been proposed for EQCM construction, which yields multidimensional piezoelectric information and thus characterizes the PQC resonance more completely, generally via impedance analysis of a Butterworth-van Dyke (BVD) equivalent electrical circuit [8][9][10][11][12][13][14][15][16]. The BVD circuit consists of a motional arm in parallel with a static capacitance (C 0 ).…”

“…The BVD circuit consists of a motional arm in parallel with a static capacitance (C 0 ). The motional arm contains three equivalent circuit elements in series, i.e., the motional resistance (R 1 ), the motional inductance (L 1 ) and the motional capacitance (C 1 ) [8][9][10][11][12][13][14][15][16]. Therefore, the impedance-analysisbased EQCM is advantageous for its providing multiple piezoelectric information, including the resonant frequency f 0 ¼ 1= 2k ffiffiffiffiffiffiffiffiffiffi L 1 C 1 p À Á À Á and various equivalent circuit parameters, which is especially helpful to discern and/or distinguish simultaneous mass and viscodensity effects in a practical system, as quantitatively explained by the following equations.…”

Assay and Analysis for Anti- and Pro-Oxidative Effects of Ascorbic Acid on DNA with the Bulk Acoustic Wave Impedance Technique

“…Thus, either a change in double-layer capacity or a perturbation of the interfacial structure would cause changes in the static capacitance. So the small increases in C 0 may be caused by the slight influence of the addition of FeCl 3 solution upon the dielectric property between the two PQC electrodes, i.e., the FeCl 3 solution caused an increase in the charge density at the electrified interface and thus a rise in the double-layer capacitance (14,25). However, it is interesting to note that the same concentration of FeCl 3 solution resulted in a slight difference in ⌬C 0 between curve 1 (background solution) and curve 2 (DNA solution).…”

Verbesserte Kontrolle der nasschemischen Präparation anorganischer Materialien mit Hilfe der In‐situ‐Ultraschallspektroskopie

“…Zwar sind weitere, zumeist optische Methoden wie Photonenkorrelationsspektroskopie bzw. dynamische Lichtstreuung [1], Impedanzmessungen [2] und Fluoreszenz-Spektroskopie [3] zur Ermittlung der Teilchengröße in Fluiden verfügbar; sie sind jedoch nur für verdünnte Lö-sungen geeignet. Titrationsmethoden wiederum beeinflussen zwangsläufig die chemische Zusammensetzung des Systems.…”