ORCID Profile
0000-0003-1294-6138
Current Organisation
Hong Kong University of Science and Technology
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: IOP Publishing
Date: 09-2020
Abstract: The corrosion rate in a modified Hanks’ solution (containing no Ca 2+ ions) was higher than in Hanks’ solution. The increase was by a factor of ∼12 for HP Mg and AZ91, and a factor of ∼6 for WE43. This quantitatively highlights the critical role of Ca 2+ ions for Mg corrosion in synthetic body fluids. The Ca 2+ ion containing solutions produced a dense corrosion-product layer of hydroxyapatite, Ca 3 (PO 4 ) 2 ) · Ca(OH) 2 , a greater fraction of which stayed on the corroding surface (∼0.2–0.3) compared with the Ca 2+ ion free solutions which produced magnesium phosphate, Mg 3 (PO 4 ) 2 .
Publisher: Elsevier BV
Date: 2023
Publisher: Elsevier BV
Date: 2023
Publisher: AMNS
Date: 2019
DOI: 10.13182/T30853
Publisher: The Electrochemical Society
Date: 03-2023
Abstract: Electrochemical impedance spectroscopy (EIS) is used widely in electrochemistry. Obtaining EIS data is simple with modern electrochemical workstations. Yet, analyzing EIS spectra is still a considerable quandary. The distribution of relaxation times (DRT) has emerged as a solution to this challenge. However, DRT deconvolution underlies an ill-posed optimization problem, often solved by ridge regression, whose accuracy strongly depends on the regularization level λ . This article studies the selection of λ using several cross-validation (CV) methods and the L-curve approach. A hierarchical Bayesian DRT (hyper- λ ) deconvolution method is also analyzed, whereby λ 0 , a parameter analogous to λ , is obtained through CV. The analysis of a synthetic dataset suggests that the values of λ selected by generalized and modified generalized CV are the most accurate among those studied. Furthermore, the analysis of synthetic EIS spectra indicates that the hyper- λ approach outperforms optimal ridge regression. Due to its broad scope, this research will foster additional research on the vital topics of hyperparameter selection for DRT deconvolution. This article also provides, through pyDRTtools, an implementation, which will serve as a starting point for future research.
Publisher: Elsevier BV
Date: 10-2022
Publisher: Elsevier BV
Date: 05-2022
Publisher: American Chemical Society (ACS)
Date: 06-07-2022
DOI: 10.26434/CHEMRXIV-2022-RS2M8
Abstract: Electrochemical impedance spectroscopy (EIS) is a widespread characterization technique used to study electrochemical systems. However, several shortcomings still limit the application of this technique. First, EIS data is intrinsically noisy, hindering spectra regression and prediction at unknown frequencies. Second, many physicochemical properties, such as the polarization resistance, are determined through non-unique equivalent circuits. Third, probed frequencies are usually log-spaced with a fixed number of points per decade, which is not necessarily optimal. This article illustrates how Gaussian processes (GPs) can overcome these three issues by showing that GPs can successfully filter EIS data and be used to determine the polarization resistance as a stochastic variable. Lastly, a GP-based, active-learning framework is developed to select EIS frequencies optimally for quick and accurate measurements.
Publisher: Wiley
Date: 22-10-2023
Location: Korea, Republic of
No related grants have been discovered for Baptiste Py.