An evaluation of the stability of concrete by Nyquist criterion

Mei-lun, Shi; Chen, Zhiyuan; Sun, Jian

doi:10.1016/s0008-8846(99)00141-6

Cited by 6 publications

(2 citation statements)

References 4 publications

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“…An equivalent circuit was utilized to model the impedance data, thus enabling the extraction of electrical parameters, such as resistance, from the impedance spectra [40,41]. Figure 4 shows the AC impedance spectra of the CPE (a), Au-CPE (b), Mb-CPE (c), and Mb-Au-CPE (d), respectively, obtained in 0.1 M pH 7.0 PBS.…”

Section: Impedance Characterization Of Mb-au-cpementioning

confidence: 99%

Electrocatalysis via Direct Electrochemistry of Myoglobin Immobilized on Colloidal Gold Nanoparticles

Liu

2003

Electroanalysis

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The direct electron transfer between immobilized myoglobin (Mb) and colloidal gold modified carbon paste electrode was studied. The Mb immobilized on the colloidal gold nanoparticles displayed a pair of redox peaks in 0.1 M pH 7.0 PBS with a formal potential of ±(0.108 AE 0.002) V (vs. NHE). The response showed a surface-controlled electrode process with an electron transfer rate constant of (26.7 AE 3.7) s À1 at scan rates from 10 to 100 mV s À1 and a diffusioncontrolled process involving the diffusion of proton at scan rates more than 100 mV s À1 . The immobilized Mb maintained its activity and could electrocatalyze the reduction of both hydrogen peroxide and nitrite. Thus, the novel renewable reagentless sensors for hydrogen peroxide and nitrite were developed, respectively. The activity of Mb with respect to the pseudo peroxidase with a K M app value of 0.65 mM could respond linearly to hydrogen peroxide concentration from 4.6 to 28 mM. The sensor exhibited a fast amperometric response to NO 2 À reduction and reached 93% of steady-state current within 5 s. The linear range for NO 2 À determination was from 8.0 to 112 mM with a detection limit of 0.7 mM at 3s.

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Section: Impedance Characterization Of Mb-au-cpementioning

confidence: 99%

Electrocatalysis via Direct Electrochemistry of Myoglobin Immobilized on Colloidal Gold Nanoparticles

Liu

2003

Electroanalysis

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“…To make a better thorough inquiry into the transformation of cement-based materials' microstructure under electrochemical conditions, cementitious materials can be divided into three phases: solid phase, liquid phase, and solid-liquid interface, and the ion contents and its double-layer structures may be altered with the changes of ion and water molecules vibrating under the premise of alternating current's influence, which may lead to changes in impedance [22,23]. Since the microstructure, as the platform, can reflect the degree of carbonation in cement-based materials, there is a difference in the molar mass of reactants and products [24].…”

Section: Introductionmentioning

confidence: 99%

Evolution of Electrochemical Impedance Spectra Characteristics of Cementitious Materials after Capturing Carbon Dioxide

et al. 2023

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The electrochemical parameters of cement-based materials with different water–cement ratios in carbon curing and water curing were measured with electrochemical impedance spectroscopy (EIS). The optimized circuit model and corresponding electrical parameters were obtained to illustrate the variation of the microstructure of cementitious materials after carbon capturing. The results show that, to a large extent, the semicircle diameter in the high frequency area gradually increased along with carbon curing and water curing. However, carbon curing showed a difference that the semicircle diameter in the high frequency appeared at the minimal value at 3 days, which was higher than that at 1 day and 7 days. This should be the result of the joint influence of water content and porosity in the cement matrix. It was also found that the mass increase rates of carbonation with water–cement ratios of 0.4, 0.5, and 0.6 were basically stable at 3.4%, 5.0%, and 5.5%, respectively. The electrochemical parameters ρct2 of cement mortar corresponding to carbon curing were around three times that of water curing specimens, mainly due to the reduction of soluble materials and refinement of connecting pores in the microstructure of cementitious materials. A quadratic function correlation between the mass increase rate and ρct2 in the carbonation process of cement mortar was built, which proved that EIS analysis could be applied to monitor the carbon capturing of cement-based materials, either for newly mixed concrete or for recycled concrete aggregates.

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A nonlinear model predictive tracking control strategy for modular high-temperature gas-cooled reactors

Wang

Zeng

et al. 2018

Annals of Nuclear Energy

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An evaluation of the stability of concrete by Nyquist criterion

Cited by 6 publications

References 4 publications

Electrocatalysis via Direct Electrochemistry of Myoglobin Immobilized on Colloidal Gold Nanoparticles

Electrocatalysis via Direct Electrochemistry of Myoglobin Immobilized on Colloidal Gold Nanoparticles

Evolution of Electrochemical Impedance Spectra Characteristics of Cementitious Materials after Capturing Carbon Dioxide

A nonlinear model predictive tracking control strategy for modular high-temperature gas-cooled reactors

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